Hierarchical routing is effective for large ad hoc networks. However, it is difficult to maintain the hierarchical structure for routing due to node movement. This paper proposes an adaptive method for maintaining the hierarchical structure. The features ...

Hierarchical routing is effective for large ad hoc networks. However, it is difficult to maintain the hierarchical structure for routing due to node movement. This paper proposes an adaptive method for maintaining the hierarchical structure. The features of the proposed method are (1) the roles of nodes for the hierarchical structure are changed depending on the status of nodes in the restricted vicinity, and (2) the cluster size is adjusted so that the number of nodes in each cluster is bounded by two constants. The adaptability of the proposed method has been evaluated by theoretical considerations and simulation experiments. The results show that node roles and clusters efficiently converges to stable states because of the features. The proposed method therefore has high adaptability to node movement.

In addition to depending on wireless links ¿ which are less reliable than wired ones ¿mobile ad hoc network (MANET) introduces a unique set of operational characteristics that affect message delivery assurance. One such characteristic is that the mobility ...

In addition to depending on wireless links ¿ which are less reliable than wired ones ¿mobile ad hoc network (MANET) introduces a unique set of operational characteristics that affect message delivery assurance. One such characteristic is that the mobility of nodes in a MANET causes the topology of the entire network to alter dynamically. In particular, as change in a single link can alter entire delivery path, we note that the persistence of a message delivery route diminishes with the growth of network size. We propose to adapt a method that was proposed by Asmuth and Blakley for data communication [1] to take advantage of this lack of path persistence to enhance message delivery assurance in MANET. Specifically, we show that this adaptation can be used to improve the level of successful first delivery attempt, and reduce the variations in the network latency for delivering successive data packets. Additionally, we show that this adaptation admits dynamic adjustments to accommodate the time varying characteristics of message delivery paths in a MANET. Finally, we show that this adaptation can also be used to provide messagesecurity protection en route.

A fundamental problem in security is to guarantee correct program behavior on an un-trusted computer regardless of a user's actions. The problem appears in Digital Rights Management, Secure Boot, e-appliances, etc. All existing approaches are either ...

A fundamental problem in security is to guarantee correct program behavior on an un-trusted computer regardless of a user's actions. The problem appears in Digital Rights Management, Secure Boot, e-appliances, etc. All existing approaches are either partial or undependable. Today, dependable security is necessary not only for e-commerce, but also to ensure that, under critical conditions of information warfare, remote clients behave predictablyand securely, and cannot compromise the infrastructure.We prove that the problem of correct program execution is unsolvable without adoption of a trusted hardware platform. Since it is impractical to consider as trusted a complex computer system, we identify the minimal hardwaresupport that enables a complete solution. We propose two simple hardware mechanisms, which require minimal change to the currently popular PC architecture: (i) the use of a trusted "sealed" computing device, the "spy", and (ii)a hardware interrupt, called "two minute warning", which has the highest priority and has a pre-defined time difference from any subsequent interrupt. Finally, we incrementally build upon this minimal hardware support larger and more complex applications with guaranteed security. We call this construction the inverse security pyramid.

When considering block cipher designs, one feature that is seemingly not related to their robustness of a design is algorithmic variability, i.e. the ability to effect changes on a design that essentially leave its structure unchanged while they modify ...

When considering block cipher designs, one feature that is seemingly not related to their robustness of a design is algorithmic variability, i.e. the ability to effect changes on a design that essentially leave its structure unchanged while they modify its functional characteristics. This feature, however, is related to robustness as there are situations where a specific algorithm is either suspected to be under cryptanalytic attack or it is not considered secure any more due to a discovered weakness. The easiest action would be to change the characteristics of the algorithm in a way that obscures the cryptanalytic attack or that eliminates the cipher's weaknesses. Our focus is on this kind of changes, using as a specific case the CAST-128 cipher. The changes we consider refer to the algorithm's substitution boxes and since the creation of good substitution boxes is a highly time consuming process, we also provide a parallel algorithm for completing this task fast.

Time-driven Key Sequencing (TKS) is a key management technique that synchronizes the session key used by a set of communicating principals based on time of day. This relatively low cost method of session key synchronization has been used in specialized ...

Time-driven Key Sequencing (TKS) is a key management technique that synchronizes the session key used by a set of communicating principals based on time of day. This relatively low cost method of session key synchronization has been used in specialized distributed systems with low-end communicating devices where sessions are sparse and each session spans a short time period comprising a small number of messages.In this paper, we describe how TKS may be useful in several scenarios involving high speed computer networks. More importantly, we present a performance model of TKS and conduct a detailed analysis to determine the impact of clock drift and network latency on the required key refresh rate. We give the exact conditions for determining the range of adequate key refresh rates, and demonstrate that the derived conditions are sufficient to ensure that data are both protected and deliverable. Interestingly, these conditions may be used to obtain a key refresh rate that can tolerate a maximum amount of clock drift after other parameters inthe system are fixed.

In this paper, we focus on the problem of secure multicast in dynamic groups. In this problem, a group of users communicate using a shared key. Due to the dynamic nature of these groups, to preserve secrecy, it is necessary to change the group key whenever ...

In this paper, we focus on the problem of secure multicast in dynamic groups. In this problem, a group of users communicate using a shared key. Due to the dynamic nature of these groups, to preserve secrecy, it is necessary to change the group key whenever the group membership changes. While the group key is being changed, the group communication needs to be interrupted until the rekeying is complete. This interruption is especially necessary if the rekeying is done because a user has left (or is removed). We split the rekeying cost into two parts: the cost of the critical path ¿ where each user receives the new group key, and the cost of the non-critical path ¿ where each user receives any other keys that it needs to obtain. We present two algorithms that show the trade off between the cost of the critical path and the cost of the non-critical path. We also compare our algorithms to previous algorithms and show that our algorithms reduce the cost of the critical path while keeping thetotal cost manageable.

In this paper, several enhanced sufficient conditions are given for minimal routing in 2-dimensional (2-D) meshes with faulty nodes contained in a set of disjoint faulty blocks. It is based on an early work of Wu's minimal routing in 2-D meshes. Fault ...

In this paper, several enhanced sufficient conditions are given for minimal routing in 2-dimensional (2-D) meshes with faulty nodes contained in a set of disjoint faulty blocks. It is based on an early work of Wu's minimal routing in 2-D meshes. Fault information is coded in a 4-tuple called extended safety level associated with each node to determine the feasibility of minimal routing. Specifically, we study the existence of minimal route at a given source nodebased on the associated extended safety level, limited distribution of faulty block information, and minimal routing. An analytical model for the number of rows and columns that receive faulty block information is also given. Extensions to Wang's minimal-connected-components (MCCs) fault model are also considered. Simulation results show substantial improvement in terms of higher percentage of minimal routing in 2-D meshes under both fault models.

As a lot of softwares are developed and distributed via the Internet, the number of accesses to the file servers, such as ftp servers or WWWservers, is increasing. To reduce the concentrated accesses to the original file server, the mirror servers which ...

As a lot of softwares are developed and distributed via the Internet, the number of accesses to the file servers, such as ftp servers or WWWservers, is increasing. To reduce the concentrated accesses to the original file server, the mirror servers which have the same directories and files as what the original server stores have been introduced. However, the inconsistency among the mirror servers and the original server is often observed because of the transferring latency, traffic congestion on the network, and management policy of the mirror servers. Hence, we develop an intermediate ftp proxy server system PFTPD (Proxy FTP Daemon) which guarantees the freshness of the files as well as the dispersal of the accesses concentrated to the original ftp server. We found out that the proposed system can dispersethe accesses to the mirror servers with a little overhead. This technology can assure files to be the latest version and adapt to the heterogeneous network environment such as the Internet.

This paper focuses on flow control in high-speed networks. Each node in the networks handles its local traffic flow only on the basis of the information it knows, but it is preferable that the decision-making of each node leads to high performance of ...

This paper focuses on flow control in high-speed networks. Each node in the networks handles its local traffic flow only on the basis of the information it knows, but it is preferable that the decision-making of each node leads to high performance of the whole network. To this end, we investigated the behavior of packet flow when a node is congested, and show an appropriate flow control model through simulation results.

The advancement of mobile telecommunication has made mobile commerce possible. It has been increasing even more that the requirement for mobile commerce to provide not only location aware but also timely services for daily life, which cannot be satisfied ...

The advancement of mobile telecommunication has made mobile commerce possible. It has been increasing even more that the requirement for mobile commerce to provide not only location aware but also timely services for daily life, which cannot be satisfied through the global information services such as e-business on the Internet. !! In the retail business under the evolving market, the users would like to utilize convenient services provided by the retailers within accessible area certainly. The retailers need to grasp the current requirements of the majority of the users in their own vicinity trade-areas in order to determine the appropriate services, which are called the Local Majority based services. This service marketing information should be temporary because the users consisting of the Local Majority and their requirement constantly change. More over the available service has a time limit and the area should become narrower with the time.Reliable communication between the retailers and the users is required for the provision of the services. Real-time property is also required for the marketing of the users' requirements and the provision of the Local Majority based services. Achieving assurance for these requirements under the evolving situation is required.Time Distance, which changes with the situation such as the congestion of the street, is introduced as the efficient measure of the distance between the users and the retailers. The Time Distance Oriented Service System has been defined to satisfy real-time property and reliable communication in the local trade area, where the users and the retailers have cooperative roles both for the provision and utilization of the services under the evolving situations. The system architecture, and the autonomous interactive communication between the users and the retailers are presented. Here, nodes have autonomy for fading unnecessary and inconvenient information through time distance based communication among them both for the marketing and provision. The nodes also autonomously reduce the information service area for achieving further effectiveness.It is shown that this architecture and technologies realize assurance for the real-time properties and reliability and achieve effectiveness in mobile commerce.

Internet auctions have got attention with the sensational diffusion of the Internet, because we are able to trade various goods for a desirable price. Many Internet auctions adopt the English auction. The English auction is the mechanism to settle a ...

Internet auctions have got attention with the sensational diffusion of the Internet, because we are able to trade various goods for a desirable price. Many Internet auctions adopt the English auction. The English auction is the mechanism to settle a successful bidder. Conventional Internet auction systems are using one logical server called an auction server that is constructed with one or several servers. So, if simultaneous bids occur, the load of the auction server increases. Besides, when congestion at circumference of the auction server occurs, the response time will increase. We propose a new Internet auction method using decentralized selection servers which will reduce superfluous information derived from bidders. The proposed method tends to hold down the increase of the response time by lightening the processing load at an auction server and cutting down congestion around the auction server. In order to evaluate the proposed method concisely, we assume a typical auction service and a network. We evaluate the proposed and the conventional methods by simulation experiments using a network simulator OPNET Modeler. Consequently, it is shown that the proposed method is more scalable and can be deployed with smaller cost.

We propose an efficient mechanism that is used to manage network with XML. It is an XML-based Dynamic network management system using Web. We describe a paradigm for the retrieval and presentation of management data using XML. It facilitates runtime ...

We propose an efficient mechanism that is used to manage network with XML. It is an XML-based Dynamic network management system using Web. We describe a paradigm for the retrieval and presentation of management data using XML. It facilitates runtime agent extension and allows the MIB to be easily browsed and seamlessly integrated with online documentation. XML also allows the interchange of data between management systems .In this paper, we propose an XML -based Dynamic network management architecture using Web. The proposed architecture is implemented using Java and its push technology for the management of IP network.

Assurance technology is a general term for technology that utilizes a system which considers the two elements of heterogeneity and adaptability. There are various needs in railway systems, so assurance properties are also being sought for train control ...

Assurance technology is a general term for technology that utilizes a system which considers the two elements of heterogeneity and adaptability. There are various needs in railway systems, so assurance properties are also being sought for train control systems. Coexistence of heterogeneous systems and adaptability for smooth system replacement are sought within daily operational changes. In this paper we model train control systems and propose an assurance evaluation method.

This paper discusses distributed checkpointing with "Time Warp techniques", a typical uncoordinated check-pointing technique that is often used in the parallel and distributed simulations. Relaxing the assumption of the previous model of Soliman et al., ...

This paper discusses distributed checkpointing with "Time Warp techniques", a typical uncoordinated check-pointing technique that is often used in the parallel and distributed simulations. Relaxing the assumption of the previous model of Soliman et al., we show a discrete time model where the number of available checkpoints each process can hold is finite. In addition, we propose an adaptive distributed checkpointing technique, that gives an effective time arrangement of checkpoints for a recovery point distribution, and we give numerical examples.

Recently the system needs of growing systems including heterogeneous functions and operations are increased. Assurance system that achieves high reliability and high availability is very important for such systems. In order to realize high assurance ...

Recently the system needs of growing systems including heterogeneous functions and operations are increased. Assurance system that achieves high reliability and high availability is very important for such systems. In order to realize high assurance system, we researched the step-by-step construction technique with assurance technology. In this paper we mainly discuss the evaluated measure for step-by-step construction. The functional reliability and the online functional availability are the best measure in order to decide the order of the step-by-step system construction. According to the measure, the functional group construction is the best solution.

Lecture-on-Demand (LOD) multimedia presentation technologies among the network are mostoften used in many communication services. Examples of those applications include video-on-demand, interactive TV and the communication tools on a distance learning ...

Lecture-on-Demand (LOD) multimedia presentation technologies among the network are mostoften used in many communication services. Examples of those applications include video-on-demand, interactive TV and the communication tools on a distance learning system and so on. In this paper, we describe how to present different multimedia objects on aweb-based presentation system. The distributed approach is based on an extended timed Petri net model. Using characterization of extended media streaming technologies, we developed a Web-based Multimedia Presentation System. For a real-world example, supposea well-known teacher is giving a lecture/presentation to his student. Because of time constraints and other commitments, many students cannot attend the presentation. The main goal of our system is to provide a feasible method to record and represent a lecture/presentation in the air. Using the browser with the windows media services allows those students to view live video of the teacher giving his speech, along with synchronized images of his presentation slides and all the annotations/comments. In our experience, thisvery approach is sufficient to the use of distance learning environment.

In recent years, as the demand of taking lectures without the limitation of time and place by those who have jobs and require life-long education grows, there are more and more expectations on the implementation of a Distance Learning System. However, ...

In recent years, as the demand of taking lectures without the limitation of time and place by those who have jobs and require life-long education grows, there are more and more expectations on the implementation of a Distance Learning System. However, in most of the existing asynchronous distance learning systems, the images shown on screen are limited to the images of the teacher with synchronized digital documents used in lectures. Since these systems have not been able to convey interactions between a teacher and students, the educational effectiveness is lower than the traditional lecture. This paper describes a distance learning system, which supports interactions between a teacher and students in asynchronous distance learning. During synchronous distance learning, This system can record interactionsautomatically with XML. It can provide recorded interactions to students who are studying asynchronously. An important point to emphasize is not only synchronizing digital documents with recorded lecture video but also synchronizing recorded interactions with digital documents and lecture video. Moreover in order to support interactions, this system also links similar questions together and can suggest the most meaningful question.

We have developed a multimedia communication environment for children, handicapped and elderly people. This environment, named "F-Communication system," is based on self-explanatory components and multiple interfaces. It allows users to manipulate the ...

We have developed a multimedia communication environment for children, handicapped and elderly people. This environment, named "F-Communication system," is based on self-explanatory components and multiple interfaces. It allows users to manipulate the components and send multimedia messages only by operations with mouse clicks. In this paper, self-explanatory components for the communication and an overview of two interfaces of the system are presented.

Application programs on application servers issue requests to object servers in traditional database systems. On the other hand, programs named agents move around object servers whose objects are manipulated objects in a mobile agent approach. If an ...

Application programs on application servers issue requests to object servers in traditional database systems. On the other hand, programs named agents move around object servers whose objects are manipulated objects in a mobile agent approach. If an agent conflicts with other agents on an object server, the agents negotiate with each other to resolve the confliction. An agent moves to another servers. In traditional systems, application programs do not work if application servers are faulty. If the server is faulty, the agent find another server where the agent can be performed. In addition, agents are replicated if agents may be faulty. In the mobile agent approach, applications can be operational even if a computer where an agent exist is faulty. In this paper, we discuss how to perform agents with different constraints on multiple object servers in presence of servers and agent faults.

So far, we have proposed Flexible Multimedia System (FMS) that is able to guarantee end-to-end QoS according to priority of parameters and consensus policy. On interconnected computer networks we can communicate with each other using realtime media such ...

So far, we have proposed Flexible Multimedia System (FMS) that is able to guarantee end-to-end QoS according to priority of parameters and consensus policy. On interconnected computer networks we can communicate with each other using realtime media such as audio and video by distributed multimedia system that can integrate various realtime and discrete media data. The multimedia system is required to realize end-to-end quality of service (QoS) guarantee functions. When users communicate with each other on interconnected different bandwidth networks, if the system can use translator or mixer functions that are defined by RTP, it will be able to guarantee more flexible QoS considering to wide band through narrow band networks. In addition, the system is able to organize various multimedia services dynamically. The FMS is mobile agent based system, therefore the system will be able to organize translator or mixer dynamically. In this paper, we discuss about QoS guarantee functions using mobile agent and re-design our prototype system to use mobile transcoding functions for flexible multimedia communication.

With the spread of Internet, the number of users and hosts has been increased exponentially. Also, newly emerging services try to provide users with more enhanced Quality of Service (QoS). The increase of users and hosts and the enhancement of QoS have ...

With the spread of Internet, the number of users and hosts has been increased exponentially. Also, newly emerging services try to provide users with more enhanced Quality of Service (QoS). The increase of users and hosts and the enhancement of QoS have caused a radical increase of Internet traffic. As a result, it is very difficult for users to find required information and the information location. In this paper, we propose a matchmaking recruiting system over the Internet. Our system is based on agent technology. The agent carries out the matchmaking using a knowledge base the same as the human beings. By using the agent, the proposed system is able to get the best matching data and decreases the Internet load.

Data servers for multimedia applications like News-on-Demand represent a severe bottleneck, because a potentially very high number of users concurrently retrieve data with high data rates. In the Intermediate Storage Node Concept (INSTANCE) project, ...

Data servers for multimedia applications like News-on-Demand represent a severe bottleneck, because a potentially very high number of users concurrently retrieve data with high data rates. In the Intermediate Storage Node Concept (INSTANCE) project, we develop a new architecture for Media-on-Demand servers that maximizes the number of concurrent clients a single server can support. Traditional bottlenecks, like copy operations, multiple copies of the same data element in main memory, and checksum calculation in communication protocols are avoided by applying three orthogonal techniques: network level framing (NLF), zero-copy-one-copy memory architecture, and integrated error management. In this paper, we describe how to minimize the transport level protocol processing using NLF. In particular, we look at how NLF is implemented, and we present performance measurements indicating a large performance gain. The protocol execution is minimized to about 450 cycles per packet regardless of packet size, i.e., a reduction of about 87 % compared to 1 KB packets and more using larger packets. Consequently, the total server-side processing over-head is decreased by at least 50 %.

In distributed applications, a group of multiple processes are cooperating where multimedia messages are exchanged among the processes. The multimedia objects are longer than traditional messages and are structured. If messages transmitted in a network ...

In distributed applications, a group of multiple processes are cooperating where multimedia messages are exchanged among the processes. The multimedia objects are longer than traditional messages and are structured. If messages transmitted in a network are causally delivered by using traditional group protocols, computation and communication overheads areincreased due to large size of multimedia data. In this paper, we discuss new types of causally precedent relations among multimedia objects transmitted in a group of multiple processes. We discuss a protocol to causally deliver multimedia objects in a group of processes.

In recent years, information devices with network communication ability have become very popular, and many people actually own such kind of devices. Those information devices, however, do not share users' data in spite of their communication ability. ...

In recent years, information devices with network communication ability have become very popular, and many people actually own such kind of devices. Those information devices, however, do not share users' data in spite of their communication ability. This paper proposes"OCEAN: Object1 Communication Environment for Arbitrary Network", which provides liaison of objects stored in each device according to their profiles and situations. It eliminates redundant user operation on information devices, and enables novel communication scheme among users by sharing common objects in those devices. Furthermore, it is also adaptive for various network environments such as unstable wirelessconnection, low cost performance connection, or stable permanent wired connection. A prototype implementation is currently under development for commercial use.

Abstract This paper describes the functional requirement and architecture of a software system called Personal Web Space (PWS). A PWS is a system to manage the information from the Web, for either leisure or work related use. Similar to bookmarks, a ...

Abstract This paper describes the functional requirement and architecture of a software system called Personal Web Space (PWS). A PWS is a system to manage the information from the Web, for either leisure or work related use. Similar to bookmarks, a PWS stores a set of URL addresses but, in addition, it caches on a proxy server pages of high interest. PWS is developed through a evolutionary process that is outlined in the paper. First, a method is prescribed to rank a page (or an URL address) based on the degree of importance to a person as determined by search engine responses and user input. Second, the information stored in a PWS must be refreshed periodically to keep up with the new state of information available on network; therefore a technique is proposed for determining and monitoring freshness. Thirdly, a PWS evolves through enlargement to include more information domains, or refinement to concentrate on smaller sub-domains. The paper describes how enlargement and refinement operations are mapped on to the stored PWS data dictionary. Finally, keyword queries can be issued against a PWS to get interesting information quickly. In this sense, a PWS uses a combination of information caching, information retrieval and bookmarks technique to enhance significantly user performance on the Web.

Because of the growth of the Internet commerce, the individual online transactions will grow up rapidly. So in this paper we proposed an interactive negotiation agent system on the Internet to help buyers to make decision. We use multi-attribute utility ...

Because of the growth of the Internet commerce, the individual online transactions will grow up rapidly. So in this paper we proposed an interactive negotiation agent system on the Internet to help buyers to make decision. We use multi-attribute utility theory as the basic decision making strategy and the theorem is useful for the decision of multi criteria. We stated the user's goal that can be divided into several independent goals and the sub goals can be negotiated with sellers in parallel. On the other hand the user cannot handle the complex process individually, we take advantage of the agent technology as the major system developed approach.

Cooperative Search Engine (CSE) is a distributed search engine, which can update indexes in very short time for the purpose of fresh information retrieval. In CSE, the retrieval performance is dependent on cache contents because communication delay occurs ...

Cooperative Search Engine (CSE) is a distributed search engine, which can update indexes in very short time for the purpose of fresh information retrieval. In CSE, the retrieval performance is dependent on cache contents because communication delay occurs at retrieval time. In the other hand, however, cache is invalidated as soon as indexes are updated. Therefore, we need persistent cache that can hold valid data before and after updating. In this paper, we describe the principle and evaluations of persistent cache.

Due to the increasing number of registered trademarks, it is more and more difficult to design and register a new trademark without a good retrieval method. Thus, we propose a new region based shape description method, the distance-angle pair-wise histogram, ...

Due to the increasing number of registered trademarks, it is more and more difficult to design and register a new trademark without a good retrieval method. Thus, we propose a new region based shape description method, the distance-angle pair-wise histogram, as the trademark shape feature vector to retrieve similar trademarks. Experiments have been conducted on about 1000 trademark images. Some moment-based methods have also been implemented. In general, the proposed method performs better than other moment-based methods.

This paper presen ts the design and implementation of a continuous media file system, which has been implemented in the context of a distributed multimedia application development environment that has been prototyped. To make a performance analysis of ...

This paper presen ts the design and implementation of a continuous media file system, which has been implemented in the context of a distributed multimedia application development environment that has been prototyped. To make a performance analysis of file systems and distributed object services for continuous media provisioning, we validate the performance analysis of file system on media-on-demand (MOD) systems against that of a conventional file system through an experimental evaluation.

Motion estimation plays an important role in image processing, since temporal information has been regarded as a promising feature for both image segmentation and video coding. In this paper, a hybrid approach is proposed to integrate differential (gradient-based) ...

Motion estimation plays an important role in image processing, since temporal information has been regarded as a promising feature for both image segmentation and video coding. In this paper, a hybrid approach is proposed to integrate differential (gradient-based) optical flow approach and region-based matching approach to search for the accurate object motion vectors. Our method adopts the Horn-Schunck optical flow constraint, in conjunction with several proposed techniques to convert the dense optical flow field to region-based motion field, and thereby suppress noises. The region-based matching approach is a modified version of traditional block-matching algorithm, so that it can operate in region-based mode, and thereby enhance the visual effectiveness near the edges. Therefore, the proposed hybrid method has the tendency to obtain the estimation of "true" object motion inherited bygradient-based approach, and also the superior visual effectiveness inherited by block-matching approach.

In this paper, we will describe the development of our Scene Context Dependent Key Frame Selection method to reduce the amount of recording video data. We propose the use of motion analysis (MA) to adapt to scene content in our Key Frame Selection Process. ...

In this paper, we will describe the development of our Scene Context Dependent Key Frame Selection method to reduce the amount of recording video data. We propose the use of motion analysis (MA) to adapt to scene content in our Key Frame Selection Process. Based on the information generated by the motion analysis stage, frames in the video sequence which contain significant motion information will be selected to retain for recording. We also show that our proposed method performs better than traditional time-lapse recording method.

High-speed fixed network is not suitable to be applied to the distributed remote monitoring environment because its lack of mobility. Therefore, the wireless communication is another choice of transmission. This paper proposes a transmission service ...

High-speed fixed network is not suitable to be applied to the distributed remote monitoring environment because its lack of mobility. Therefore, the wireless communication is another choice of transmission. This paper proposes a transmission service to classify the transmitted data into three kinds of transmission events. Three priority queues are used to receive the corresponding events and transmit these data according to their priority. By this mechanism, some of the data, that are out of date and not to influence the monitoring environment, could be discarded. In this way, the cost to transmit data for monitoring is reduced. This paper also proposes mechanisms to handle the data ordering and encoding problems. To verify the advantage of this transmission service, an implemented prototype is proposed based on the GSM short message system. The proposed prototype also compared the time and data lose rate with the unique queue, three queues mechanisms. The results show that the average wait time of the transmitted data packet and the transmission cost are reduced.

We have constructed Information Communication Processing System (ICPS) and Advanced ICPS (AICPS) as a kind of gateway system using communication service network to provide PC communication service (on-line dial-up service) to users (customers). Users ...

We have constructed Information Communication Processing System (ICPS) and Advanced ICPS (AICPS) as a kind of gateway system using communication service network to provide PC communication service (on-line dial-up service) to users (customers). Users could connectICPS or AICPS using 01410/01411/01412 connection dial number, especially management of 01412 PC communication service network resource provides resource data through one Local O&M System (LOMS) per each AICPS. Nation-wide integrated network management has been provided centralized integration operating network management service through POWWOW-NMS which manages Network Elements (NEs) in PC communication network. We implemented network management system (NMS) of POWWOW-NMS in PC communication network. We also analyze SNMP polling-based network management in comparison with agent-based network management.

It is popular for application to combine virtual reality and network multimedia technique. The 3D geometry models are used in such applications. It is difficult to build mathematical models by human. The reverse-engineering is a new method to build 3D ...

It is popular for application to combine virtual reality and network multimedia technique. The 3D geometry models are used in such applications. It is difficult to build mathematical models by human. The reverse-engineering is a new method to build 3D models. Such a model is suitable for Internet transmission. It is still a bottleneck for using the Reverse-engineering to reconstruct relationship between vertices. The a-Shapes is an old method for it. In this study, we propose some methods to improve its efficiency. ompare our improved algorithm with original algorithm. Our method could generate compact model. The average storage space required by our method is about half of the one by original method. The advantage of our method is not only in the storage space but also in the reconstruction time.

A packet switched network such as the Internet provides only the best-effort service for users. Recent studies for the characterisitics of the packet arrival on the packet switched network have shown a self-similar property with a long-range dependence, ...

A packet switched network such as the Internet provides only the best-effort service for users. Recent studies for the characterisitics of the packet arrival on the packet switched network have shown a self-similar property with a long-range dependence, and also show the heavy-tailed distribution. This paper investigates the end-to-end performance of the Internet empirically. It focuses on the inter-arrival process of packets and the property of the packet loss between end-to-end hosts. We show that both the inter-arrival process and loss events have self-similar with a long-range dependence property. The inter-arrival process of packetshas the heavy-tailed distribution which sums up the difference of all queues in intermediate routers.

The objective of joint rate control is to achieve a better and more uniform picture quality by exploiting the complexity of each program. In this paper, a novel joint rate control scheme is presented for real time coding of multiple video programs. In ...

The objective of joint rate control is to achieve a better and more uniform picture quality by exploiting the complexity of each program. In this paper, a novel joint rate control scheme is presented for real time coding of multiple video programs. In our scheme, the total available channel bandwidth is firstly assigned to each program in proportion to its information content. A novel control scheme, which is adaptive to the variation of distributed bandwidth, is thenpresented in our design to determine quantization parameters and the number of skipping frames for each program. As a result, the proposed scheme can be considered as a "look current" scheme, which outperforms many existing ones in terms of coding complexity and video quality.

In video-on-demand (VOD) applications, it is desirable to provide the user with the video-cassette-recorder-like (VCR) capabilities such as fast-forwarding a video or jumping to a specific frame. We address this issue in the broadcast framework, where ...

In video-on-demand (VOD) applications, it is desirable to provide the user with the video-cassette-recorder-like (VCR) capabilities such as fast-forwarding a video or jumping to a specific frame. We address this issue in the broadcast framework, where each video is broadcast repeatedly on the network. Existing techniques rely on data prefetching as the mechanism to provide this functionality. This approach provides limited usability since the prefetching rate cannot keep up with typical fast-forward speeds. We address this practical problem in this paper by repeatedly broadcasting the interactive versions of the videos. Ourclient software leverages these "interactive" broadcasts to provide better VCR service.

We focus on how to generate well-written texts to describe an object from a database, and propose several strategies that are needed in generation stages. To build reliable generation rules, we performed corpus analysis through annotating descriptive ...

We focus on how to generate well-written texts to describe an object from a database, and propose several strategies that are needed in generation stages. To build reliable generation rules, we performed corpus analysis through annotating descriptive texts. This paper alsodescribes an implemented text generation system called XExplainer, which can dynamically produce a description of an object in Korean. XExplainer was applied to two domains ¿ a home shopping database and a business administration database ¿ to show that it can be applied to any domain as long as the information is provided in the required format. The Generated texts were evaluated by humans using several criteria, such as content completeness, structural coherence, expression conciseness, and text layout.

The management of large collections of music data in a multimedia database has received much attention in the past few years. In the most of current works, the researchers extract the features from the music data and develop indices that will help to ...

The management of large collections of music data in a multimedia database has received much attention in the past few years. In the most of current works, the researchers extract the features from the music data and develop indices that will help to retrieve the relevant music quickly. Several reports have pointed out that these features of music can be transformed andrepresented in the forms of music feature strings. However, these approaches lack of scalability while increasing the music data. In this paper, we propose an approach to transform the music data into a numeric forms and develop an index structure base on R-tree for effective retrieval. The experimental results show that our approach outperforms existing string index approaches.

In this paper, a general concept called n+k/n method is introduced. In n+k/n method, a special mapping function is defined to map an intermediate set with n+k bits into n bits information set. In the embedding process, the intermediate set is embedded ...

In this paper, a general concept called n+k/n method is introduced. In n+k/n method, a special mapping function is defined to map an intermediate set with n+k bits into n bits information set. In the embedding process, the intermediate set is embedded into cover image rather than embedding the information set. If the distance between the features of coverimage and the bits of intermediate set is less than that between the features and information bits, the better cover image quality can be gained. According to the idea of n+k/n method, a special case called n+1/n method is proposed. In this method, the mapping function is an exclusive-or operation. When an information set is given, two sets which satisfy the mapping function can be got. The one which has smaller distance from feature bits is selected as intermediate set. In the paper, it is proved that the maximun distance between the intermediate set and feature set is less than the average distance between the information set and the feature set. The reduction rate of feature modification for n+1/n method will reach 25%, and the improving quality in embedded cover image is more than 2.5db..

This paper describes implementations and test results of Elliptic Curve Cryptography (ECC) and Elliptic Curve Digital Signature Algorithm (ECDSA) algorithms based on Java card. 163-Bit ECC guarantees as secure as 1024-Bit Rivest-Shamir-Adleman (RSA) ...

This paper describes implementations and test results of Elliptic Curve Cryptography (ECC) and Elliptic Curve Digital Signature Algorithm (ECDSA) algorithms based on Java card. 163-Bit ECC guarantees as secure as 1024-Bit Rivest-Shamir-Adleman (RSA) public key algorithm, which has been frequently used until now. According to our test results, 163- bit ECC processing time is about five times fast compared with 1024-bit RSA and amount of resource usages of ECC is smaller than RSA. Therefore, ECC is more appropriate for use on secure devices such as smart cards and wireless devices with constrained computational power consumption and memory resources.

The popularity of the Internet has opened up many ways to distribute information to a desired audience. The information usually comes in the way of web sites, chat rooms, newsgroups, etc.Although the above methods of presenting information are invaluable, ...

The popularity of the Internet has opened up many ways to distribute information to a desired audience. The information usually comes in the way of web sites, chat rooms, newsgroups, etc.Although the above methods of presenting information are invaluable, technology has come to the stage in which a more robust method of presenting information can be widelydistributed. This paper presents a new method to distribute information through the use of real-time, three dimensional graphics, which can be easily created, modified and viewed in most web browsers using standard Internet protocols. In addition to viewing three dimensional presentations, the 3D environment's creator and visitors to that environment have the option of being present, in the form of avatars, inside the virtual world, similar in concept to a virtual classroom. This allows the virtual world's creator to move around the scene and point out various areas of interest, and allows visitors to move around the scene, viewing the presentation and asking questions of the creator.

In this paper, we propose a user-friendly three-dimensional CG presentation system for a typical traditional Japanese crafting industry based on agent and virtual reality functions over Japan Gigabit Network (JGN) which is a testbed highspeed backbone ...

In this paper, we propose a user-friendly three-dimensional CG presentation system for a typical traditional Japanese crafting industry based on agent and virtual reality functions over Japan Gigabit Network (JGN) which is a testbed highspeed backbone networkwith 2.4Gbps. A large number of traditional Japanese fittings in a local city are redesigned by three-dimensional computer graphics into CAD data and stored in the database servers distributed over JGN. Although each fitting data consists of more than several Mbytes size, user can interactively retrieve the desired fittings and put those into the traditional Japanese interior to design more creative and original houses, hotels and other buildings in realtime. We prototyped a presentation system using VRML and JAVA on networked CG workstations. User can walk through the desired virtual space as a Japanese interior organized by various Japanese traditional fittings and iteractively change those fittings by selecting from the database and replacing by simple operations. As a result, we could verify the usefulness of our suggested system not only for Japanese crafting but also for worldwide design industries.

Despite the advances in software technology, there are still problems that need to be solved. They are related to understanding components, modifying them and their interfaces, etc., as well as to the practical use of Component-Based Development (CBD) ...

Despite the advances in software technology, there are still problems that need to be solved. They are related to understanding components, modifying them and their interfaces, etc., as well as to the practical use of Component-Based Development (CBD) for large-scale applications.Our approach is based on developing multiple view components of multimedia types. These multiple views can be divided into a few groups to represent different features of a component: (1) computational schemes of a corresponding component algorithm, (2) variables and formulas used in the algorithm, and (3) input/output (I/O) operations of the component. Such approach simplifies the understanding and manipulation of components.This paper discusses examples of visualizing I/O specifications which include the definition of data source and the corresponding target, scanning schemes applied to structures, conditions imposed upon different operations, etc. In other words, a visual language to define external inter-component interfaces is presented.

Multimedia applications are becoming increasingly important in areas such as education (digital libraries, training, presentation, distance learning), healthcare (telemedicine, health information management, medical image systems), entertainment (video-on-demand, ...

Multimedia applications are becoming increasingly important in areas such as education (digital libraries, training, presentation, distance learning), healthcare (telemedicine, health information management, medical image systems), entertainment (video-on-demand, music databases, interactive TV), information dissemination (news-on-demand, advertising, TV broadcasting), and manufacturing (distributed manufacturing, distributed collaborative authoring)[1]. In this paper we introduce a visual software engineering tool which is part of a suite of tools called MICE used for the rapid prototyping of distributed multimedia applications.

As the Internet evolves toward the global multi-service network of the future, a key consideration is support for services with guaranteed quality of service (QoS). The current Internet has a number of barriers to QoS support for real-time data delivery ...

As the Internet evolves toward the global multi-service network of the future, a key consideration is support for services with guaranteed quality of service (QoS). The current Internet has a number of barriers to QoS support for real-time data delivery such as the lack of control architectures. The proposed differentiated services (Diffserv) framework is seen as the key technology to achieve this. This paper examines standard transport layer protocols, i.e. UDP and TCP, suited for real-time data delivery over Diffserv-capable networks where bandwidth guarantees are provided. We designed a streaming video application that buffers a portion of data on the receiver before starting the playback and operates in a streaming mode. Streaming media applications currently used in the Internet use UDP because of the general belief that TCP's reliable delivery mechanisms such as congestion control and retransmission are unsuitable for time-sensitive delivery. However, TCP showed the better simulation results than UDP when packets are lost over Diffserv networks. In our simulation, TCP can adapt its sending rate to the guaranteed bandwidth and the buffer on the receiver allows TCP to retransmit lost packets before the playback. As for TCP, the employment of SACK option that can recover lost packets efficiently contributes to the better performance.

Differentiated services (DiffServ) model is a potential solution for providing quality of services (QoS) on the Internet. In this paper, we propose a scalable architecture that fulfills the design philosophy of the DiffServ model. Different from other ...

Differentiated services (DiffServ) model is a potential solution for providing quality of services (QoS) on the Internet. In this paper, we propose a scalable architecture that fulfills the design philosophy of the DiffServ model. Different from other existing architectures, our proposed architecture puts complexity on edge routers so that core routers do not need to support any specific function for service differentiation. Further, the proposed architecture only needs few additional functions in edge routers. Thus its deployment is simpler than most existing architectures. We also address how to achieve weighted proportional fairness solely by edge routers.

Current admission controls aiming to maximize network utilization create a bias against large-bandwidth calls. This paper proposes a BNP (buffer without preemption) model which will hold a call in a buffer rather than directly reject it when the residual ...

Current admission controls aiming to maximize network utilization create a bias against large-bandwidth calls. This paper proposes a BNP (buffer without preemption) model which will hold a call in a buffer rather than directly reject it when the residual bandwidth is insufficient. No other call can be admitted until this queued call is served. Such a mechanism increases throughput because the buffer can temporarily hold a call, and reduces the bias for large-bandwidth calls because all calls will be rejected when the buffer is not empty, even the residual bandwidth is enough for small-bandwidth calls. The novel is compared with other two alternative models, NB (no buffer) and BP (buffer with preemption), and the performance of the models is analyzed by solving a two-dimensional Markov chain. The analytical results indicate that the proposed model can achieve perfect fairness. Meanwhile, some numerical results confirm that the novel approach achieves higher fairness than the two competing models.

Continuous media applications have an implied temporal dimension, i.e. they are presented at a particular rate for a particular length of time and if the required rate of presentation is not met the integrity of these media is destroyed. We present a ...

Continuous media applications have an implied temporal dimension, i.e. they are presented at a particular rate for a particular length of time and if the required rate of presentation is not met the integrity of these media is destroyed. We present a set of language constructs suitable for the definition of the required QoS and the real-time dimension of the media that participate in a multimedia application. We propose a new modeling scheme where we can represent every different presentation by a periodic task and then we describe a method that provideslow-level support to these language constructs. The emphasis of the proposed strategy is given on deterministic guarantees and can be considered as a next step for the design and the implementation of predictable continuous media applications over a network.

One of the features of wireless ad hoc network technology is that networks can be constructed without a fixed network infrastructure. Communication in a disaster is one application of a mobile ad hoc network. Data on the disaster can be collected by ...

One of the features of wireless ad hoc network technology is that networks can be constructed without a fixed network infrastructure. Communication in a disaster is one application of a mobile ad hoc network. Data on the disaster can be collected by mobile hosts. The mobile hosts can then exchange data to decide rescue priority, etc. However,connectivity in a wireless ad hoc networks is not guaranteed because hosts more and encounter obstacles. Thus, the accessibility of the data objects held in a particular host is very important. To ensure accessibility, we propose a method for distributing replicas of regional data on mobile ad-hoc networks.

In this paper, QOS Control of realtime multimedia communication system under heterogeneous environment by the wired and the wireless networks is proposed. In our suggested system, as channel coding, FEC (Forward Error Correction) method with Reed-Solomon ...

In this paper, QOS Control of realtime multimedia communication system under heterogeneous environment by the wired and the wireless networks is proposed. In our suggested system, as channel coding, FEC (Forward Error Correction) method with Reed-Solomon coding is introduced to reduce the packet error rate on the wireless network. On the other hand, as source coding, transcoding methods including transformation of various video codings such as M-JPEG, MPEG and Quicktime, controls of Q-factor within a frame, frame rate and color depth is introduced to maintain the required QOS, particularly the end-to-end throughput. The increases of the required bandwidth by redundant packet addition with FEC can be suppressed by the transcoding functions while the packet error rate is reduced to the accepted value. In order to verify the functionality and the efficiency in our suggested system, numerical simulation was held. As the result, our suggested system by combination of transcoding and FEC could correct the packet error rate with an order of 109 while maintaining the frame rate and the amount of data transform at a constant.

Performance of mobile agent in obtaining the aimed data is evaluated by a computersimulation in terms of the number of mobile agents. As a preparation for the simulation, two parameters "target existing rate" and "living time" of mobile agent are identified ...

Performance of mobile agent in obtaining the aimed data is evaluated by a computersimulation in terms of the number of mobile agents. As a preparation for the simulation, two parameters "target existing rate" and "living time" of mobile agent are identified through the experiment on the internet. This paper suggests that these parameter are essential factors for distinguishing the suitable situation of using mobile agent for obtaining the aimed data.

Wireless communication that provides voice only is not sufficient to support the necessity of user. It is an important feature of next generation wireless communication to offer this capability through mobile Internet. Mobile IP allows mobile hosts to ...

Wireless communication that provides voice only is not sufficient to support the necessity of user. It is an important feature of next generation wireless communication to offer this capability through mobile Internet. Mobile IP allows mobile hosts to change their location and reduce the losing probability of data packets in wireless communication networks. However, mobile IP still have some defects in handoff and route aspects. Therefore, cellular IP protocol is proposed for routing of IP diagrams to mobile stations and fast handoff control in a limited geographical area. It can cooperate with mobile IP to provide wide area mobility support. In this paper, a handoff method is proposed to improve Quality of Service and resource switchingmanagement to reduce data packet loss for mobile multimedia communication in cellular IP and mobile IP network.

Nokia is a globally distributed company. It has many sites in Europe, Americas and Asia. This means that in many cases also the development teams are distributed. This paper explains the problems that exist among the distributed teams concerning the ...

Nokia is a globally distributed company. It has many sites in Europe, Americas and Asia. This means that in many cases also the development teams are distributed. This paper explains the problems that exist among the distributed teams concerning the selected target case andintroduces the objectives and the requirements that Nokia had concerning the project MOTION. Also, the user story and the process for evaluating the implementation are discussed.

Peer-to-peer systems recently captured the attention of practitioners and researchers as they provide an attractive alternative to client-server architectures. Peer-to-peer enables the creation of massively distributed networks of data repositories that ...

Peer-to-peer systems recently captured the attention of practitioners and researchers as they provide an attractive alternative to client-server architectures. Peer-to-peer enables the creation of massively distributed networks of data repositories that can be setup and discarded easily according to applicative needs. Nevertheless, the current popularity of these systems is due mostly to their use for file sharing over the Internet.In this paper, we argue that the advantages of a peer-to-peer architecture reach well beyond the realm of Internet file sharing. In particular, they become key in supporting enterprise processes and especially collaborative work involving mobile users. To support ourview, in this paper we report about the design of an architecture and a core communication middleware in the EU project MOTION, where a peer-to-peer architecture is exploited to support collaboration among mobile and geographically distributed users.

One of the problems faced by large, global organizations and enterprises is to effectively enable their employees to collaborate across locations. People need collaborative work support while they are on the move and have to share business documents ...

One of the problems faced by large, global organizations and enterprises is to effectively enable their employees to collaborate across locations. People need collaborative work support while they are on the move and have to share business documents and know-how. Although much work has been done in the area of Computer Supported Collaborative Work (CSCW) to date, supporting mobility is only recently receiving attention. Hence, most of the existing approaches do not deal with emerging mobile teamwork requirements such as locating business documents and expertise through distributed searches, advanced subscription and notification, community building, and mobile information sharing and access. Furthermore, existing applications and approaches are usually difficult to customize to business-specific processes and requirements. The MObile Teamwork Infrastructure for Organizations Networking (MOTION)1 system addresses these requirements and provides a generic teamwork services Application Programming Interface (API), TWSAPI, that can be used to build organization-specific collaborative applications. In this paper, we give an overview of the MOTION TWSAPI and illustrate its usage in building an application that provides document review support.

This paper focuses on the problem of coordinating the movements of a cooperative team in an environment, and proposes an approach that takes inspiration from the laws of physics. The idea is to have the movements of team members driven by abstract force ...

This paper focuses on the problem of coordinating the movements of a cooperative team in an environment, and proposes an approach that takes inspiration from the laws of physics. The idea is to have the movements of team members driven by abstract force fields, generated by team members themselves (i.e., by carried-on devices) and propagated via some embedded infrastructure (or by team members in an ad-hoc way). A globally coordinated and self-organized behavior in team members' movements emerges due to the interrelated effects of team members following the shape of the fields and of dynamic fields re-shaping. A case study in the area of warehouse management is introduced to exemplify the proposed approach.

One of the central issues in facilitating mobile teamwork is the creation and establishment of teams from autonomous agents. It is widely accepted that team building assumes an expression of, and agreement on, common interests. This paper describes a ...

One of the central issues in facilitating mobile teamwork is the creation and establishment of teams from autonomous agents. It is widely accepted that team building assumes an expression of, and agreement on, common interests. This paper describes a new approach to the provision of mechanisms to facilitate the creation of teams and to help resolve conflict through automated negotiation. The negotiation mechanism is mplemented by a combination of a game theory approach and a co-evolutionary approach. This scheme involves a processthat iterates over the generation of a set of strategies by the co-evolutionary approach, the encoding of these strategies into a payoff matrix, and the reasoning on the matrix by the game theory approach in order to find an optimised point. The process terminates when the gametheory approach finds an optimised point that satisfies both agents. The main advantage of this system is that agents, without knowing each other's strategies, agree on an optimised solution that conforms to Nash equilibrium and Pareto efficiency.

Product development processes increasingly happen in cooperations, where cooperation partners are dislocated in time and space. This leads to the fact that teamworkers have to be more and more mobile and brings us to the presumption that the support ...

Product development processes increasingly happen in cooperations, where cooperation partners are dislocated in time and space. This leads to the fact that teamworkers have to be more and more mobile and brings us to the presumption that the support of spontaneous information exchange and mobile ad hoc interaction among team members will gain in importance. Some of the questions that have to be answered when building tools for supporting mobile teamwork as well as the requirements for such tools will be discussed in this paper.

In the last decade, bureaucratic organizational hierarchies increasingly have been replaced with flatter organizational forms, bringing together people from different disciplines to form project teams within and between organizations. Distributed project ...

In the last decade, bureaucratic organizational hierarchies increasingly have been replaced with flatter organizational forms, bringing together people from different disciplines to form project teams within and between organizations. Distributed project teams often are self-configuring networks of mobile and "fixed" people, devices, and applications. They are the natural next step in the evolution of distributed computing, after client-server, Web-based, and peer-to-peer computing. A newly emerging requirement is to facilitate not just mobility of content (i.e. to support a multitude of devices and connectivity modes) to project members, but also mobility of context (i.e. to provide traceable and continuous support of relationshipsbetween people, artifacts, and business processes). The contribution of this paper is to present the design goals, the architecture, and implementation of a system aiming at supporting mobility of context for project teams, enabling traceable and continuous support ofassociations (relationships) between people, artifacts, and business processes.

Communication is the basis of all cooperation. Messaging is an important form of communication. A universal messaging service (UMS) developed by Telenor Mobil is presented. Features and architecture for UMS are presented. Possible development directionsfor ...

Communication is the basis of all cooperation. Messaging is an important form of communication. A universal messaging service (UMS) developed by Telenor Mobil is presented. Features and architecture for UMS are presented. Possible development directionsfor UMS are discussed, including more sophisticated support for groups and group awareness.

Mobile teamwork applications are often deployed in heterogeneous environments with various devices and connections. To support a broad variety of platforms for mobile teamwork in heterogeneous environments, this paper presents a framework for development ...

Mobile teamwork applications are often deployed in heterogeneous environments with various devices and connections. To support a broad variety of platforms for mobile teamwork in heterogeneous environments, this paper presents a framework for development ofapplications adaptive to the client's computing platform. The framework supports both shared data adaptation and user interface adaptation to user's preferences and display characteristics. Both shared data and the user interface are specified in two XML documents. The user interface XML document specifies the application interface by a generic "view" graph (should also specify the valid data types). Global view graph is transformed into a device-dependant view graph for individual client devices.

In mobile teamwork environments two basic problems exist: how to discover someone based on a profile (skills, reputations) and how to assess that person's "credibility" (trust). A lot of work has been done on the issues of collecting and spreading reputations ...

In mobile teamwork environments two basic problems exist: how to discover someone based on a profile (skills, reputations) and how to assess that person's "credibility" (trust). A lot of work has been done on the issues of collecting and spreading reputations and subsequent computation of trust. The application of such data for decision making, however, is still missing. In this paper we present a solution for scheduling exchanges among participants of an online community which take into account their trustworthiness.

We address the problem of dealing with the heterogeneity of access devices. The problem we are facing is that of a, possibly mobile, user that wants to download and execute an application from a remote server. The user's hosting device can be of various ...

We address the problem of dealing with the heterogeneity of access devices. The problem we are facing is that of a, possibly mobile, user that wants to download and execute an application from a remote server. The user's hosting device can be of various kinds PCs, PDAs, cellular phones, communicators, etc. with specific hardware and software capabilities. The problem is then to be able to decide whether the user's current device characteristics arecompatible with the application requirements in order to prevent execution failures. In the negative case we would like to be able to identify the reasons that determined the uncompatibility and perform an adaptation of the application so that it can match the user's device capabilities.

The first step given to separate concepts in web environments has been to take apart presentation from data. This split has been gotten due to the appearance of the ExtensibleMark-up Language (XML) and the application of style sheets. The new ideas from ...

The first step given to separate concepts in web environments has been to take apart presentation from data. This split has been gotten due to the appearance of the ExtensibleMark-up Language (XML) and the application of style sheets. The new ideas from the advanced separation of concerns community and the new abstractions like aspects make us think this original division isn't rich enough. There are important concepts of Internet applications that should be defined separately. If we look at new web design methodologies,we can realize that one of these aspects is navigation. Following the way started by XML, we propose the use of the XML Linking Language (XLink) as a first stage to obtain the separation of the navigational aspect.

Web services dramatically increase the reach of e-business. A homogeneous model that spans internal as well as external resources enables uniform solutions to complex business problems. Yet, the complexity of web-service-based systems increases exponentially ...

Web services dramatically increase the reach of e-business. A homogeneous model that spans internal as well as external resources enables uniform solutions to complex business problems. Yet, the complexity of web-service-based systems increases exponentially with theirscope. Separation of crosscutting concerns and active management of aspects are fundamental in web-service-based solutions.In this paper, we first introduce web services and the concept of business interaction concerns. We then propose a process-oriented approach to the modelling of aspects deriving from crosscutting business concerns. We focus on the dynamic nature of web-service-basedsolutions, and the need for adaptive management of aspects. In particular, we propose a technique for the dynamic distribution of aspects across multiple web-service components. The technique is based on explicit definition of process roles.The proposed approach has been used to build experimental solutions involving dynamic reconfiguration of web-service system. We present an application example in the context of supply-chain integration that was prototyped using the DySCo platform (Dynamic e-ServiceComposer).

In the development of agent applications, interactions are an important issue, which must be faced with appropriate methodologies and tools. A separation of concerns between the agents and their interaction needs is helpful in the designing and the implementation ...

In the development of agent applications, interactions are an important issue, which must be faced with appropriate methodologies and tools. A separation of concerns between the agents and their interaction needs is helpful in the designing and the implementation phasesof the life cycle. In this paper we propose XRole, a system that helps in dealing with interactions. It is based on the definition of roles, which are intended as intermediaries between the application needs and the environment needs. XRole is realized exploiting theinteresting features of the XML language. An application example shows the effectiveness of the approach.

We propose a layered architecture based on the separation of two concerns ¿ computation and coordination ¿ as a means of achieving higher levels of auto-adaptability. This separation makes it possible for adaptation to be enforced through the reconfiguration ...

We propose a layered architecture based on the separation of two concerns ¿ computation and coordination ¿ as a means of achieving higher levels of auto-adaptability. This separation makes it possible for adaptation to be enforced through the reconfiguration of the system in terms of the mechanisms that coordinate interactions, superposing connectors among components of the system without intruding on the way the computations that they perform locally are implemented.

With modern software systems, an important requirement is the ability to be auto adaptive, i.e. being able to adjust itself its changing environment. In line with this, a run time manager for dynamic feature integration of telecommunication systems, ...

With modern software systems, an important requirement is the ability to be auto adaptive, i.e. being able to adjust itself its changing environment. In line with this, a run time manager for dynamic feature integration of telecommunication systems, interaction detection andresolution is described in this paper with aspects being used to implement features. The manager manages the interaction of features/aspects by monitoring the managed program. The program is represented by a labelled transition system (LTS) model, stored in a flexible data structure, and executed by calling action subroutine represented by the label of the LTS model, forming a reflective facility for the composition and analysis of features. It is the reflective mechanism that makes dynamic feature addition, run time model checking, as well as adaptive interaction resolution possible. Runtime model checking is possible because thechecked program is stored within itself, and the interaction resolution will be done by selecting behaviour traces according to the resolution rules.

This work presents an infrastructure that simplifies the development of distributed applications that can adapt automatically to nonfunctional properties of their components and of their execution environment. This infrastructure, based on the programming ...

This work presents an infrastructure that simplifies the development of distributed applications that can adapt automatically to nonfunctional properties of their components and of their execution environment. This infrastructure, based on the programming language Lua and on CORBA, allows applications to select dynamically the components that best suit their requirements, to verify whether the system is satisfying these requirements, and to react, when appropriate, to variations in the nonfunctional properties of the services in use. We use CORBA's Trading Service to support dynamic component selection. An extensible mon-itoringfacility supports monitoring of dynamically defined requirements. We use the Lua language to specify adaptation strategies, and a smart proxy mechanism to apply these strategies.

The separation of concerns, as a conceptual tool, enables us to manage the complexity of the software systems that we develop. Such was the intent behind the OORAM [7]. When the idea is taken further to software packaging, greater reuse and maintainability ...

The separation of concerns, as a conceptual tool, enables us to manage the complexity of the software systems that we develop. Such was the intent behind the OORAM [7]. When the idea is taken further to software packaging, greater reuse and maintainability are achieved. There have been a number of approaches aimed at modularizing software around the naturalboundaries of the various concerns, including subject-oriented programming [2] aspect-oriented programming [3], and our own view-oriented programming [4]. The same applications that warrant the kind of separation supported by the above techniques tend also to be distributed where different users may be interested in different aspects of the application at different times. In this paper, we look at distribution in the context of the separation of concerns, and present an approach to distributing objects that embed different aspects.

Many middleware platforms use computational reflection to support adaptive functionality. Most approaches in-tertwine the activity of observing behavior (introspection) with the activity of changing behavior (intercession). This paper explores the use ...

Many middleware platforms use computational reflection to support adaptive functionality. Most approaches in-tertwine the activity of observing behavior (introspection) with the activity of changing behavior (intercession). This paper explores the use of language constructs to separate these parts of reflective functionality. This separation and "packaging" of reflective primitives is intended to facilitate the design of correct and consistent adaptive middleware. A prototype language, called Adaptive Java, is described in which this functionality is realized through extensions to the Java programming language. A case study is described in which "metamorphic" socket components are created from regular socket classes and used to realize adaptive behavior on wireless network connections.

Scaling applications to large networks and an increasing number of users has been since years a technical challenge. Today, technologies are well known to scale applications to local networks but scaling to large networks with high latency is still a ...

Scaling applications to large networks and an increasing number of users has been since years a technical challenge. Today, technologies are well known to scale applications to local networks but scaling to large networks with high latency is still a challenge.DLBS (Dynamic Load Balancing Service) brings new solutions regarding large scale load balancing for middleware based applications. DLBS offers a multi-criteria and easily customizable load balancing service. It consists of a scalable monitoring infrastructure, a connection manager (integrated into the middleware) and customizable load balancing strategies.Implementation of a low level service requires in order to stay efficient to avoid the necessity for high overhead. DLBS aims to be a generic load balancing service and an easy and efficient portability with a CORBA Object Request Broker has been possible thanks to Aspect Oriented Programming.

Research on aspect oriented programming and specification has highlighted the need to deal with cross-cutting concerns that involve more than one implementation level component. Distributed systems are an important application area where cross-cutting ...

Research on aspect oriented programming and specification has highlighted the need to deal with cross-cutting concerns that involve more than one implementation level component. Distributed systems are an important application area where cross-cutting concerns frequently emerge.We present a novel way of composing distributed behavior from reusable superposition steps. The steps are given in a joint action notation, which allows introducing logically related data and operations in several implementation level components simultaneously. A superposition step contains a description of the context in which it is applicable, and the additional structure to add to a specification.Aspects of collective behavior may overlap at the implementation level. To make it possible to separate aspects cleanly at the specification level, our specification method allows entities to be merged in composition to allow an implementation level entity to play multiple specification level roles.

Configuring distributed applications at deployment time requires the introduction of high-level features such as transaction and synchronization into application's code. Component models like CORBA Component Model (CCM) or Enterprise Java Beans (EJB) ...

Configuring distributed applications at deployment time requires the introduction of high-level features such as transaction and synchronization into application's code. Component models like CORBA Component Model (CCM) or Enterprise Java Beans (EJB) allow programmers to declare in deployment descriptors which services have to be plugged into components. However, these approaches do not allow a dynamic integration of new services. In this paper,we propose a reflexive approach allowing service integration into component at runtime. When a new service is added to a component, the combination with existing services is managed dynamically by the platform.

This paper summarizes an actor-based middleware in Java for the development of time-dependent distributed systems. The approach centres on the separation of concerns.Functional, synchronization, control and configuration aspects of an application can ...

This paper summarizes an actor-based middleware in Java for the development of time-dependent distributed systems. The approach centres on the separation of concerns.Functional, synchronization, control and configuration aspects of an application can separately be dealt with in a design so as to favour the fulfilment of the application requirements. Actors are encapsulation units of data and behaviour and are modelled as finite state machines. They enable ubiquitous computing. Actors have location transparent names and can migrate, possibly autonomously, from node to node of an heterogeneous computinginfrastructure like Internet, for accomplishing their computational task. Actors are based on an explicit messaging system. Crosscutting concerns in group of actors can be programmed in special actors (synchronizers) which transparently filter message exchanges and superimpose to them timing and synchronization constraints which directly affect message scheduling. The paper describes the implementation of a real-time multimedia QoS synchronizer.

Event-based communication models provide interesting properties for distributed systems such as asyn hronism and type-based selection mechanisms.The Comet middleware we develop proposes such an event-based communication model as foundation.From this ...

Event-based communication models provide interesting properties for distributed systems such as asyn hronism and type-based selection mechanisms.The Comet middleware we develop proposes such an event-based communication model as foundation.From this canonical model, we show how to build more conventional bidirectional and synchronous interactions with extended features such as impli it type-based multi ast or asynchronous perationalization. Furthermore,we demonstrate the use (and interest)of the lower-level asynchronous model to develop highly flexible distributed services.We illustrate this idea with a publish/subscribe protocol that can be dynamically reconfigured to match various requirements:type-based or content-based filtering semantics, peer-to-peer or mediator-based configurations.

This position paper addresses the issue of supporting quality of service (QoS) parameters in distributed publish-subscribe systems. It advocates that QoS parameters should be handled using the same constructs as other information regarding events, such ...

This position paper addresses the issue of supporting quality of service (QoS) parameters in distributed publish-subscribe systems. It advocates that QoS parameters should be handled using the same constructs as other information regarding events, such as their type or content. At the same time, we claim that the use of a consistent set of mechanisms should not preclude to decouple the specification of QoS properties from the specification of type, subject or content-based constraints.We also advocate that QoS parameters should not be embedded on the type or content of the events. We show that some QoS parameters can only be computed in run-time, as they depend on dynamic aspects such as the location of the participants and the system load.The paper proposes a model that supports the decoupling of QoS characterization from the event characterization while, at the same time, offers an uniform treatment of both aspects.

The publish/subscribe communication model is increasingly considered for implementing middleware infrastructures for widely distributed applications. Scalability issues and routing algorithms of such systems have recently been the focus of intensive ...

The publish/subscribe communication model is increasingly considered for implementing middleware infrastructures for widely distributed applications. Scalability issues and routing algorithms of such systems have recently been the focus of intensive research. So far little attention has been given to security and management issues.In current publish/subscribe systems, malicious publishers can very easily insert bogus notifications which may propagated to a large number of subscribers. Moreover, there is no method to control what notifications the subscribers are authorized to receive.We describe a method to specify access control policy rules using expressions similar to subscription expressions. These policies define access rules for publish and subscribe functions and screening rules for notifications.

Event notification services are used in various applications, for example, stock tickers, environmental monitoring, and facility management. Several filtering algorithms for such services have been proposed. The best performance results are achieved ...

Event notification services are used in various applications, for example, stock tickers, environmental monitoring, and facility management. Several filtering algorithms for such services have been proposed. The best performance results are achieved by tree-based algorithms. However, to our knowledge existing algorithms do not consider the influence of event and profile distribution on the filter performance. In this paper we propose a distribution-dependent improvement of the tree-algorithm. We present the test results of our prototypical implementation that show the influence of various distribution-based measures on the performance.

We define formally the data models WP and AWP especially designed for the dissemination of textual information in distributed event-based systems. We also define the problems of satisfiability, satisfaction, filtering and entailment, and point out that ...

We define formally the data models WP and AWP especially designed for the dissemination of textual information in distributed event-based systems. We also define the problems of satisfiability, satisfaction, filtering and entailment, and point out that these problems are fundamental for the deployment of models like the ones presented here in distributed event-based systems.

An important class of publish/subscribe matching algorithms work in two stages. First, predicates are matched and then matching subscriptions are derived. We observe that in practice, the domain types over which predicates are defined are often of fixed ...

An important class of publish/subscribe matching algorithms work in two stages. First, predicates are matched and then matching subscriptions are derived. We observe that in practice, the domain types over which predicates are defined are often of fixed enumerable cardinality. Based on this observation we propose a table-based look-up scheme for fast predicate evaluation that finds all matching predicates for each type with one table lookup. We compare this scheme to alternative general-purpose implementations. This observation may also suggests that matching in publish/subscribe systems could equally well be implemented with standard database technology. We propose two DBMS-based matchingalgorithms and compare the better one with a special purpose publish/subscribe matching algorithm implementation. We provide first evidence that for application scenarios that require large subscription workloads and process many events a DBMS-based solution is not a feasible alternative.

Online personalisation is of great interest to companies. Event notification systems are becoming more and more popular as a natural candidate to provide personalised services.Although event notification protocols do not immediately spring to mind as ...

Online personalisation is of great interest to companies. Event notification systems are becoming more and more popular as a natural candidate to provide personalised services.Although event notification protocols do not immediately spring to mind as the most sensible transport of real-time streams, our approach does utilise a content-based event notification protocol. In this paper we present an architecture able to correlate and filter real-time multimedia streams using an event notification protocol (Elvin) and the Real-Time Transport Protocol (RTP). We demonstrate, through simple examples, how a MPEG-2 stream can becustomised to the user in real-time based on his or her subscription. Such an architecture can serve as enabling technology to integrate, correlate and abstract different sources of information such as discrete and continuous events.

There are many challenges in devising solutions for on-line content processing of live networked multimedia sessions. These include the computational complexity of featureextraction and high-level concept recognition, the massive amount of data to be ...

There are many challenges in devising solutions for on-line content processing of live networked multimedia sessions. These include the computational complexity of featureextraction and high-level concept recognition, the massive amount of data to be analyzed under real-time requirements and the intricate correspondence between low-level features and high-level concepts. Our approach to these challenges is a distributed architecture consisting of interacting components encapsulating feature extraction and concept classifier algorithms. The purpose of the framework is to simplify the development of applications for the domain of on-line multimedia content processing.In this paper we focus on the architecture of the framework and argue that it fits well to the publish/subscribe interaction paradigm, leading to an event-based interaction model. Furthermore, we analyze different aspects of the application domain in more depth, such as requirements for scalability, reconfiguration, migration, event notification selection, filtering, and ordering. The main contribution of this paper is, that we for each aspect show how a suitableevent notification service may satisfy the corresponding requirements. We also describe parts of a framework prototype. In particular we report on how the event notification service used satisfies the identified requirements.

The increasing popularity of information services that rely on content delivery in mobile environments motivates the need for a mobile push service ¿ an efficient and flexible content dissemination service that targets mobile users. We analyze the features ...

The increasing popularity of information services that rely on content delivery in mobile environments motivates the need for a mobile push service ¿ an efficient and flexible content dissemination service that targets mobile users. We analyze the features of a mobile push service by investigating representative usage scenarios and propose an architecturefor mobile content delivery systems. The architecture is based on the publish/subscribe (P/S) paradigm which supports many-to-many interaction of loosely-coupled entities. We define the set of services that need to collaborate with the P/S infrastructure to address the dynamics of mobile environments.

Sensor networks are distributed event-based systems that differ from traditional communication networks in several ways: sensor networks have severe energy constraints, redundant low-rate data, and many-to-one flows. Data-centric mechanisms that perform ...

Sensor networks are distributed event-based systems that differ from traditional communication networks in several ways: sensor networks have severe energy constraints, redundant low-rate data, and many-to-one flows. Data-centric mechanisms that perform in-network aggregation of data are needed in this setting for energy-efficient information flow. In this paper we model data-centric routing and compare its performance with traditional end-to-endrouting schemes. We examine the impact of source-destination placement and communication network density on the energy costs and delay associated with data aggregation. We show that data-centric routing offers significant performance gains across a wide range of operational scenarios. We also examine the complexity of optimal data aggregation, showing that although it is an NP-hard problem in general, there exist useful polynomial-time special cases.

Composite events are required for many applications that require obtaining events from varioussources, correlating them, and activating appropriate actions. One of the major issues in composite event system is scalability. This paper reports on a research ...

Composite events are required for many applications that require obtaining events from varioussources, correlating them, and activating appropriate actions. One of the major issues in composite event system is scalability. This paper reports on a research that follows the situation concept of the Amit system, and proposes a parallel execution model for the event composition. The paper describes the model and its difficulties, and shows its usefulness using simulation results

In this paper, the event concept is applied to support the interaction between mobile users and distributed location-aware systems. Taking a number of examples, the components of an event specification language are derived that can be used beyond the ...

In this paper, the event concept is applied to support the interaction between mobile users and distributed location-aware systems. Taking a number of examples, the components of an event specification language are derived that can be used beyond the domain of location-aware systems.

In this work we propose an architecture for distributed multimedia applications based on an event-driven programming model. To avoid the synchronization problems inherent to multi-threaded programming, the proposed architecture is based on a single-threaded ...

In this work we propose an architecture for distributed multimedia applications based on an event-driven programming model. To avoid the synchronization problems inherent to multi-threaded programming, the proposed architecture is based on a single-threaded structure. Instead of multi-threading, we opted for the event-oriented approach allied to multiple communication channels with user-defined handling procedures to allow the application to deal concurrently with control and data streams. We discuss this programming model, present the system we have implemented based on this model, and describe the experience we have had with this system.

This paper presents a survey of existing event systems structured as a taxonomy of distributed event-based programming systems. Our taxonomy identifies a set of fundamental properties of event-based programming systems and categorizes them according ...

This paper presents a survey of existing event systems structured as a taxonomy of distributed event-based programming systems. Our taxonomy identifies a set of fundamental properties of event-based programming systems and categorizes them according to the event model and event service criteria. The event service is further classified according to its organization and interaction model, as well as other functional and non-functional features.

The coordination paradigm has been used extensively as a mechanism for softwarecomposition and integration. However, relatively little work has been done for the cases where the software components involved have real-time requirements. The paper presents ...

The coordination paradigm has been used extensively as a mechanism for softwarecomposition and integration. However, relatively little work has been done for the cases where the software components involved have real-time requirements. The paper presents an extension to a state-of-the-art control- or event-driven coordination language with real-time capabilities. It then illustrates the expressiveness of the proposed extensions by means of modeling a distributed multimedia application. Finally, it discusses how these extensions can be supported by the underlying architecture.

Tuple-based coordination models are a successful tool for harnessing the complexity of interactions in open and highly dynamic systems. Recently, coordination infrastructures such as JavaSpaces and TSpaces have been proposed for event-based systems as ...

Tuple-based coordination models are a successful tool for harnessing the complexity of interactions in open and highly dynamic systems. Recently, coordination infrastructures such as JavaSpaces and TSpaces have been proposed for event-based systems as well,promoting the mechanism of event notification at the coordination level. In this paper, we investigate how the foundation of tuple-based coordination models is affected by the idea of applying them to event-based scenarios.Since existing semantics models seem quite inadequate to this purpose, we present a new formal framework where the behaviour of the coordination medium is defined in terms of the events it produces and consumes. To stress the usefulness of our approach, we discuss how the formal framework can be used to extend the basic tuple-space model with the event notification mechanism. The application of coordination models to event-based systems alsosuggests to reconsider the traditional issue of coordination models' expressiveness. Correspondingly, we sketch a novel approach to characterise the expressiveness of a coordination medium.

Content-based publish/subscribe systems mediate between publishers of information and subscribers who sign up to receive information, by routing messages across the network from their source of publication to the point of subscription using the message ...

Content-based publish/subscribe systems mediate between publishers of information and subscribers who sign up to receive information, by routing messages across the network from their source of publication to the point of subscription using the message content. The routing information is derived from the subscriptions. One particular problem faced by content-based publish/subscribe systems is how to turn the speci£cation of complex subscriptions into routing information that can be distributed across the network.In this paper, we describe a new declarative language for specifying composite events based on the typed ë -calculus. Composite events are represented in this language by cur-riedfunctional expressions, i.e., functions that can be called with less arguments than parameters and which return as a result an updated version of the function with the remaining parameters. Events which are components of the composite event are passed as arguments to such expressions, and the resulting evaluation produces a functional expression which represents the current state of the composite event. A property of this language, derived from a property of the ë -calculus, is that results can be converted back to the expressions from which they were produced. We exploit this property to show how an expression representing a compositeevent can be converted into an expression from which routing information can be derived.

In this paper, we argue that there is a need for an event-based middleware to build large-scale distributed systems. Existing publish/subscribe systems still have limitations compared to invocation-based middlewares. We introduce Hermes, a novel event-based ...

In this paper, we argue that there is a need for an event-based middleware to build large-scale distributed systems. Existing publish/subscribe systems still have limitations compared to invocation-based middlewares. We introduce Hermes, a novel event-based distributed middleware architecture that follows a type- and attribute-based publish/subscribe model. It centres around the notion of an event type and supports features commonly known fromobject-oriented languages like type hierarchies and super-type subscriptions. A scalable routing algorithm using an overlay routing network is presented that avoids global broadcasts by creating rendezvous nodes. Fault-tolerance mechanisms that can cope with different kinds of failures in the middleware are integrated with the routing algorithm resulting in a scalable and robust system.

A key issue when designing and implementing large-scale publish/subscribe systems is how to efficiently propagate subscriptions among the brokers of the system. Brokers require this information in order to forward incoming events only to interested users, ...

A key issue when designing and implementing large-scale publish/subscribe systems is how to efficiently propagate subscriptions among the brokers of the system. Brokers require this information in order to forward incoming events only to interested users, filtering out unrelated events, which can save significant overheads (particularly network bandwidth and processing time at the brokers). In this paper we contribute the notion of subscription summaries, a mechanism appropriately compacting subscription information. We develop the associated data structures and matching algorithms. The proposed mechanism can handle event/subscription schemata that are rich in terms of their attribute types and powerful in terms of the allowed operations on them. Our major results are that the proposed mechanism (i) is scalable, with the bandwidth required to propagate subscriptions increasing only slightly, even at huge-scales, and (ii) is significantly more efficient, up to orders of magnitude, depending on the scale, with respect to the bandwidth requirements for propagating subscriptions.

This paper addresses the fundamental tradeoffs in event systems between scalability (of event filtering, routing, and delivery mechanisms), expressiveness (when describing interests in events), and event safety (ensuring encapsulation and type-safe interaction ...

This paper addresses the fundamental tradeoffs in event systems between scalability (of event filtering, routing, and delivery mechanisms), expressiveness (when describing interests in events), and event safety (ensuring encapsulation and type-safe interaction with polymorphic events). We point out some ramifications underlying these tradeoffs and we propose a pragmatic approach to handle them. We achieve scalability using a multi-stage filtering strategy that combines approximate and perfect matching techniques for the purpose of event routing and filtering. We achieve expressiveness and event safety by viewing events as objects, i.e., instances of application-defined abstract types.

A large-scale distributed supervisory system that services a large area should ideally be capable of performing automatically optimal control based on various types of data provided by the controlled equipment. However, conventional systems have generally ...

A large-scale distributed supervisory system that services a large area should ideally be capable of performing automatically optimal control based on various types of data provided by the controlled equipment. However, conventional systems have generally been configured so that pre-ordained transmission and reception processes are the input to the FEP (front end processor) unit according to various criteria of the data provided by the controlled equipment (e.g., the type and significance of the data, its priority, and its designated destination), while the host computer sends back a response to the controlled equipment based on the data transferred from the FEP according to preset optimal control algorithm. But to achieve fundamental improvements of system speed and reduce the load on the host computer, one must adopt the configuration in which the FEP can make automatic judgments regarding thecriteria of data provided by a diverse variety of controlled equipment, instead of having to devise system-wide algorithms based on predetermined criteria in the data provided by thecontrolled equipment. To configure an FEP for this sort of system, we propose a method where a plurality of programs that identify the conditions of a specific type of data are prepared separately and integrated by means of a multi-agent architecture.

With the widespread deployment and use of wireless data communications in the mobile computing domain the need for middleware that interconnects the components that comprisea mobile application in distributed and potentially heterogeneous environments ...

With the widespread deployment and use of wireless data communications in the mobile computing domain the need for middleware that interconnects the components that comprisea mobile application in distributed and potentially heterogeneous environments arises. Middleware utilizing an event-based communication model is well suited to address the requirements of the mobile computing domain, as it requires a less tightly coupled communication relationship between application components compared to the traditionalclient/server communication model. This is particularly useful with the use of wireless technology, where communication relationships amongst application components are established very dynamically during the lifetime of the components. Recent research in the area of event-based middleware for the mobile computing domain focuses on infrastructure network models for wireless data communication. In this paper, we present STEAM, an event-based middleware service that has been specifically designed for wireless local area networks utilizing the ad hoc network model. We argue that an implicit event model is best suited for the envisaged ad hoc environment and present our approach of exploiting a novel combination of three different types of event filter to address the problems related to thedynamic reconfiguration of the network topology as well as their impact on the scalability of a system and the timely delivery of events.

The middleware technology used as the foundation of Internet-enabled enterprise systems is becoming increasingly complex. In addition, the various technologies offer a number of standard architectures that can be used by designers as templates to build ...

The middleware technology used as the foundation of Internet-enabled enterprise systems is becoming increasingly complex. In addition, the various technologies offer a number of standard architectures that can be used by designers as templates to build applications. However, there is little concrete understanding in the software industry on the strengths and weaknesses of competing technologies, and the different trade-offs that various component architectures impose. The SACT Group at CSIRO has qualitatively and quantitatively evaluated a number of commercially available Message-Oriented Middleware (MOM) systems.This paper focuses on the results obtained from the performance evaluation of the IBM's MQSeries V5.2. It presents an overview of the technology, and discusses the metric used in this study for performance measurement The test results related to the sustainableperformance of the system using various test configurations are described and their implications discussed.

In this paper we describe the model used for the NewsWire collaborative content delivery system. The system builds on the robustness and scalability of Astrolabe to weave a peer-to-peer infrastructure for real-time delivery of news items. The goal of ...

In this paper we describe the model used for the NewsWire collaborative content delivery system. The system builds on the robustness and scalability of Astrolabe to weave a peer-to-peer infrastructure for real-time delivery of news items. The goal of the system is todeliver news updates to hundreds of thousands of subscribers within tens of seconds of the moment of publishing. The system significantly reduces the compute and network load at the publishers and guarantees delivery even in the face of publisher overload or denial of service attacks.

Prolonged secure communication requires trust relationships that extend throughout a connection's life cycle. Current tools to establish secure connections such as SSL/TLS and SSH authenticate PKI identities, validate credentials and authorize a trust ...

Prolonged secure communication requires trust relationships that extend throughout a connection's life cycle. Current tools to establish secure connections such as SSL/TLS and SSH authenticate PKI identities, validate credentials and authorize a trust relationship at the time a connection is established, but do not monitor the trust relationship there-after.To maintain security over the duration of a prolonged connection, we extend the semantics of SSL to support continuous monitoring of a credential's liveness and the trustrelationships that authorize it. Our implementation isolates trust management into a pluggable trust authorization module. We also present an initial design for a host-level securecommunication resource that provides secure channels for multiple connections.

The expectation of a global presence of services leads to the need for large numbers of service instances allocated in a multitude of regional data centers in order to provide sufficient service capacity close to where the demand occurs. Scale of service ...

The expectation of a global presence of services leads to the need for large numbers of service instances allocated in a multitude of regional data centers in order to provide sufficient service capacity close to where the demand occurs. Scale of service instances is anticipated growing \gg 104 raising new challenges for control and management. Pragmatically, it must become much easier to deploy service instances in data center, allocating resources, sharing them, installing and configuring data and software needed for service instances and integrating them into a singular service that appears to a consumer.Adjusting numbers and locations of service instances is seen as a basic control mechanism in order to follow regional or temporal fluctuations in demands.The paper proposes a new concept of virtualizing whole data center environments and quickly deploying massive amounts of service instances. A virtualization layer takes care of resource allocation from different data center locations and all specifics when service instances are allocated in a particular data center. Virtualized data centers provide a consistent operating environment spanning multiple physical data center locations for thewhole family of service instances. And vice versa, physical data centers host several execution environments for different services.After a brief discussion of challenges coming with the scale of service instances we anticipate, the paper overviews virtual data centers and discusses one aspect in more detail how massive amounts of service instances can be deployed using a recursive approach.

The notion of intrinsic references, i.e. references based on the hash digest of the referent, is introduced and contrasted with that of physical references, where the referent is defined relative to the state of a physical system. A retrieval mechanism ...

The notion of intrinsic references, i.e. references based on the hash digest of the referent, is introduced and contrasted with that of physical references, where the referent is defined relative to the state of a physical system. A retrieval mechanism using intrinsic references, the Elephant Store, is presented. The use of intrinsic references in hierarchical data structures is discussed, and the advantages regarding version management, consistency and distributed storage are argued.

In this paper we focus on the design of high performance peer-to-peer content sharing systems. In particular, our goal is to achieve global load balancing and short user-request response times. This is a formidable challenge, given the requirement to ...

In this paper we focus on the design of high performance peer-to-peer content sharing systems. In particular, our goal is to achieve global load balancing and short user-request response times. This is a formidable challenge, given the requirement to respect the autonomy of peers, their heterogeneity in terms of processing and storage capacities, their different content contributions, the huge system scale, and the dynamic system environment. Our approach exploits the semantic categorization of published documents and constructs clusters of peers. We provide a formal formulation for the problem of load balancing in our setting and prove that it is NP-complete. We also present a greedy polynomial time algorithm that achieves nearly optimal load balancing as shown by our experimental results.

In many Internet scale replicated system, not all replicas can be dealt with in the same way, since some will be in greater demand than others. In the case of weak consistency algorithms, we have observed that updating first replicas having most demand, ...

In many Internet scale replicated system, not all replicas can be dealt with in the same way, since some will be in greater demand than others. In the case of weak consistency algorithms, we have observed that updating first replicas having most demand, a greater number of clients would gain access to updated content in a shorter period of time.In this work we have investigated the benefits that can be obtained by prioritizing replicas with greater demand, and considerable improvements have been achieved. In zones of higher demand, the consistent state is reached up to six times quicker than with a normal weak consistency algorithm, without incurring the additional costs of the strong consistency.

This paper envisions a shared virtual reality system that could handle millions of users and objets. The SOLIPSIS system does not rely on servers and is based on a network of peers that collaborate to build up a common virtual world. Real-time interactions ...

This paper envisions a shared virtual reality system that could handle millions of users and objets. The SOLIPSIS system does not rely on servers and is based on a network of peers that collaborate to build up a common virtual world. Real-time interactions and virtual co-presence are enabled by the means of emissive and receptive fields that determine how avatar kinestesia and multimedia streams are established. We describe here the overall architecture and the main algorithms that make SOLIPSIS conceivable.

A simple method is proposed for peer-to-peer description and discovery of resource-sharing communities as well as the resources themselves. An XML Schema document describes a shared resource. By applying transformations, specified in XSL, the schema ...

A simple method is proposed for peer-to-peer description and discovery of resource-sharing communities as well as the resources themselves. An XML Schema document describes a shared resource. By applying transformations, specified in XSL, the schema is used to generate an application with the ability to publish and search for the defined object. Meta-data is indexed and searchable allowing complex objects to be discovered. We propose to solve the problem of discovery for resource-sharing communities by treating a community as a shared resource. An XML Schema description of resource-sharing communities is used to generate a P2P system for community discovery.

As the peer-ro-peer (P2P) computing paradigm receives more and more attrention, it is now necessary to provide computing platforms to offer an environment to build P2P applications. In this paper, we describe Rheeve, a computing platform that provides ...

As the peer-ro-peer (P2P) computing paradigm receives more and more attrention, it is now necessary to provide computing platforms to offer an environment to build P2P applications. In this paper, we describe Rheeve, a computing platform that provides support for the Rheeve, acomputing platform that provides support for the development of HTTP-enabled, efficient and fault-tolerant P2P applications. Rheeve has a highly modular system architecture and scalable mechanisms for efficient peer connections and service discovery and delivery. Its work distribution and execution facility enables sharing of computation resources in a language and protocol independent manner. Rheeve also provides a visual programming interface, which, togethher with the underlying JavaBeans technology, supports a plug-n-play style of application design.

This paper deals with the interaction of all ip mobile Internet devices with networked appliances in a residential home. Two novel mechanisms are described and demonstrated: pointing as an indication of user interest, and user interface loading from ...

This paper deals with the interaction of all ip mobile Internet devices with networked appliances in a residential home. Two novel mechanisms are described and demonstrated: pointing as an indication of user interest, and user interface loading from the home appliance to a mobile Internet device. The user pointing action is used as a source to both collecting the context information of the user, and triggering the execution of the user interface loading procedure. The provided mechanisms are described in the form of a use scenario, and implemented using a session initiation protocol (SIP) and an open service gateway (OSGi) platform.

Development and projections in the field of PDAs and wireless communication architectures let us consider new applications which exploit short range and direct exchanges. In a close future we may imagine mobile users equipped with wireless PDAs dynamically ...

Development and projections in the field of PDAs and wireless communication architectures let us consider new applications which exploit short range and direct exchanges. In a close future we may imagine mobile users equipped with wireless PDAs dynamically and spontaneously exchanging rich information in an ad hoc manner. In such a context, a connection between two PDAs may be broken at any time because of the short communication range and the unconstrained mobility of the users. Thus, such spontaneous data exchanges become a real challenge. To perform spontaneous and relevant transmissions compatible with these volatile connections, we propose a method that progressively downloads information according to its importance. Then, we show an implementation of such a mechanism in a Web context by extending the actual browsers capabilities.

With the expansion of mobility in communication technologies, the increasing individual audio solicitations require a definition of priorities in audio information. A new concept called superphony is identified which improves communication abilities ...

With the expansion of mobility in communication technologies, the increasing individual audio solicitations require a definition of priorities in audio information. A new concept called superphony is identified which improves communication abilities by reconstructing an audio sphere around each user and filtering audio information based on user and environment profiles. Requirements and elements for an architecture are presented. Guaranteeing real-timeaudio stream management based on profiles in mobile contexts, without compromising security, are key issues. Several potential applications are also discussed.

In the near future, there will be increasingly powerful computers in smart cards, telephones, and other information appliances. This will create a massive infrastructure composed of highly diverse interconnected mobile entities. In this paper, we present ...

In the near future, there will be increasingly powerful computers in smart cards, telephones, and other information appliances. This will create a massive infrastructure composed of highly diverse interconnected mobile entities. In this paper, we present a data-centric approach to storage and querying in such environments. At a first level, we view each entity as a miniaturedatabase; at a second level we maintain databases of metadata and services. We describe how information delivery and querying are performed in such architectures.

The growing needs to access information in remote, mobile environments have sparked interests in so-called In-Vehicle Telematics Systems (IVTS) [1]. These relatively new systems have the potential to deliver computing facilitates to road vehicles, which ...

The growing needs to access information in remote, mobile environments have sparked interests in so-called In-Vehicle Telematics Systems (IVTS) [1]. These relatively new systems have the potential to deliver computing facilitates to road vehicles, which may include in-vehicle infotainment, route-guidance and navigation and the provision of vital information resources used by fleet haulage companies and emergency services (police, fire and ambulance). This paper describes the EmergeITS 1 project, which is concerned with the use of IVTS for emergency fire service applications. In particular, the paper describes a distributed service-based architecture, based on the Jini middleware technology, which can be used to provide fault tolerant application services to remote in-vehicle computers and mobile devicessuch as Palm devices and WAP phones.

This paper describes the Smart Operation of Networked Appliances (SONA) system which realizes the autonomous and asynchronous operation of networked appliances by using mobile agents. In SONA system, the mobile agents operate networked appliances in ...

This paper describes the Smart Operation of Networked Appliances (SONA) system which realizes the autonomous and asynchronous operation of networked appliances by using mobile agents. In SONA system, the mobile agents operate networked appliances in place of user's direct manipulation. Existing appliances operation systems such as remote controllers require users to input their demands synchronously with the appliances, while SONA system only requires users to input their demands in a lump once for all. To realize autonomous and asynchronous operation system, the SONA system is equipped with appliances lookup service, operation plan composer, and mobile agent system. In this paper, we present the design, implementation, and evaluation of SONA system.

Emulation is an efficient method in mobile Ad Hoc network research, which provides a good approach to accurately evaluate the MANET routing protocol large scale. In this paper, we describe the modeling and implementation of a new low cost MANET emulator ...

Emulation is an efficient method in mobile Ad Hoc network research, which provides a good approach to accurately evaluate the MANET routing protocol large scale. In this paper, we describe the modeling and implementation of a new low cost MANET emulator called NE based on Ethernet environment. NE provides mobile multi-hop wireless emulation including incomplete connectivity, random frame loss, bandwidth limitation and communication delay. NE is suitable for middle scale MANET emulation where the number of nodes is about one hundred.

The home is an eternal, heterogeneous, distributed computing environment which must be secure and reliable. Computers and embedded processors in the home are all different shapes and sizes and ages. Hence the home poses one of the most challenging environments ...

The home is an eternal, heterogeneous, distributed computing environment which must be secure and reliable. Computers and embedded processors in the home are all different shapes and sizes and ages. Hence the home poses one of the most challenging environments for cooperative programming. We envisage that control software is introduced into the home by four different methods varying from embedded ROM code to applets generated from a combination of natural language and gesture with wands. But we argue that, in the long term, all of it must be represented in a common, formally-verifiable language and conform to acommon scripting convention. The AutoHan project at the University of Cambridge Computer Laboratory is the umbrella under which we are trying to grow these ideas [3].

In the future, micro processors will be embedded in various appliances such as home appliances, digital AV appliances, and personal appliances. These appliances will be connected to various types of networks, such as Internet, and communicate with each ...

In the future, micro processors will be embedded in various appliances such as home appliances, digital AV appliances, and personal appliances. These appliances will be connected to various types of networks, such as Internet, and communicate with each other. The communication of appliances would integrate some services provided by these appliances and make new services.The future home computing environment requires home computing middleware on which we can control home appliances easily and develop new services without a great effort. Most of recent middleware for home computing such as Jini and HAVi has no compatibility and adaptability with each other. Therefore it is not easy for these appliances to communicate with other appliances which are controlled by any other middleware. Although there are some protocol bridges such as bridge between HAVi and Jini by Philips, Sony and Sun, these are almost only bridges of one and one. We need a framework with which we can integrate any middleware in a simpler way.In this paper, we propose a framework for connecting home computing middleware. It enables any appliance under any middleware's control to communicate any other appliances.We show also a service integration framework with Internet service and home computing middleware.

The proliferation of smart gadgets, appliances, mobile devices, PDAs and sensors has enabled the construction of ubiquitous computing environments, transforming regular physical spaces into "Active Information Spaces" augmented with intelligence and ...

The proliferation of smart gadgets, appliances, mobile devices, PDAs and sensors has enabled the construction of ubiquitous computing environments, transforming regular physical spaces into "Active Information Spaces" augmented with intelligence and enhanced with services. This new exciting computing paradigm promises to revolutionize the way we interact with computers, services, and the surrounding physical spaces, yielding higher productivity and more seamless interaction between users and computing services. However, the deployment of this computing paradigm in real-life is hindered by poor security, particularly, the lack of proper authentication and access control techniques and privacy preserving protocols.We propose an authentication framework that addresses this problem through the use of different wearable and embedded devices. These devices authenticate entities with varied levels of confidence, in a transparent, convenient, and private manner, allowing the framework to blend nicely into ubiquitous computing environments.

The current Java Application Environment for mobile terminals provides a very restricted security mechanism which is known as "the sandbox model." Although 3rd Generation Partnership Project defines access control and permission framework of a Java program ...

The current Java Application Environment for mobile terminals provides a very restricted security mechanism which is known as "the sandbox model." Although 3rd Generation Partnership Project defines access control and permission framework of a Java program in the terminal as the security domain, the specification has problems such that implementation in theterminal becomes difficult because it requires content authentication for determining the domain. In order to solve the problems and increase flexibility of mobile software services, we propose an efficient and flexible access control framework for the Java program in the mobile terminal. This framework relates a security domain to a server and utilizes the server authentication in SSL in order to determine the domain which the program belong to. As a result, downloading the program and determining the domain becomes efficient. This framework is able to apply other information appliances.

In Marc Weiser's vision of ubiquitous computing, users are located in an environment withpotentially thousands of computers around them. Many capabilities of these smart devices can be used only by augmenting the users' senses with a kind of "sixth electronic ...

In Marc Weiser's vision of ubiquitous computing, users are located in an environment withpotentially thousands of computers around them. Many capabilities of these smart devices can be used only by augmenting the users' senses with a kind of "sixth electronic sense". Thus, ubiquitous computing and wearable computing complement one another. However, the architectural styles for them are quite different.This paper presents a new flexible and modular network-centered approach for the design of wearable computers. In our concept, a wearable computer is composed of a network of modules. A module can be worn by the user or be stationary in the user's environment. Each is a separate unit with its own processing, memory, I/O, power, and network connection, and provides specific functionality in the network. The modules reveal their abilities and needs to each other and dynamically assemble to form a network-based wearable multi-computer.Our concept has been used in the dwarf framework to build a first prototype system forindoor and outdoor navigation.

This paper introduces a prototype of wearable health-care support system LifeMinder', which consists of a wristwatch-shaped wearable sensor module and a personal digital assistant (PDA). The wearable sensor module, equipped with sensors of accelerometer, ...

This paper introduces a prototype of wearable health-care support system LifeMinder', which consists of a wristwatch-shaped wearable sensor module and a personal digital assistant (PDA). The wearable sensor module, equipped with sensors of accelerometer, pulse meter,thermometer, galvanic skin reflex (GSR) electrodes and Bluetooth module to communicate with the PDA, monitors the user's context: health conditions, movements and behaviors. The system uses this information to guide the user in daily self-care in real time. Diet care and exercise care are especially significant to prevent the "lifestyle-related disease". The authors developed algorithms to recognize the user's movement from wrist motion and to detect thebeginning of a meal from pulse rates and GSR values. The accuracy of both algorithms is about 90%.

This paper describes work in progress on wearable computing configurations which provide audio and visual output based on the position and orientation of the user. We introduce the eSleeve' - a wearable wrist computer with position and heading sensors ...

This paper describes work in progress on wearable computing configurations which provide audio and visual output based on the position and orientation of the user. We introduce the eSleeve' - a wearable wrist computer with position and heading sensors combined with a user interface employing speech recognition and a small display.Applications described include searching a database of locations, and implementing a minimal augmented reality system. The effectiveness of different approaches at conveyinglocation based information is discussed and we also describe our continuing research into position based audio and visual interfaces.

Caching static HTTP traffic in proxy-caches has reduced bandwidth consumption and download latency. However, web-caching performance is hard to increase further due to the growing number of non-cachable dynamic web-documents. Delta-encoding is a promising ...

Caching static HTTP traffic in proxy-caches has reduced bandwidth consumption and download latency. However, web-caching performance is hard to increase further due to the growing number of non-cachable dynamic web-documents. Delta-encoding is a promising technique that exploits temporal correlation among different snapshots of a dynamic document, and renders dynamic traffic cachable. It achieves this by combining a cachable, previous snapshot of a document, called base-file, with small difference-file, called delta, to generate the current snapshot of the document. However, it has not yet been deployed due to the significant scalability concerns related to the storage requirements for base-files on theserver-side.In this paper we introduce class-based delta-encoding, a scalable scheme to perform delta-encoding on dynamic web-traffic. The idea is to group documents into classes, and store one document per class on the server-side. Thus, the proposed scheme exploits both temporal correlation in a dynamically evolving document, and spatial correlation among different documents. Finally, we present an architecture to deploy the scheme, that is transparent to clients, proxy-caches, and web-servers. Experimental results report thatclass-based delta-encoding combined with compression reduces the bandwidth consumption by a factor of 30, and the latency perceived by most users by a factor of 10 on average, without suffering from enormous storage requirements on the server-side.

In this paper, we present Whoops!, a clustered web cache prototype based on SciFS, a Distributed Shared Memory (DSM) that benefits from the high performances and the remote addressing capabilities of memory mapped networks like Scalable Coherent Interface ...

In this paper, we present Whoops!, a clustered web cache prototype based on SciFS, a Distributed Shared Memory (DSM) that benefits from the high performances and the remote addressing capabilities of memory mapped networks like Scalable Coherent Interface (SCI). Whoops! uses the DSM for all web cache management and cache storage. Using a memory mapped network and a DSM programming model allow us to investigate new algorithm to distribute and handle requests.We present a new implementation of TCP handoff that directly maps remote TCP/IP stacks through the network. This technique reduces processor overhead and forwards TCP acknowledgements in few microseconds.We have also designed Parallel Pull-Based LRU (PPBL), an efficient request distribution algorithm for use with DSM systems. Unlike other distribution algorithms the decision is distributed over all nodes thus providing better scalability. PPBL supports multi-frontend environments letting the DSM handle data distribution.Finally, Whoops! implements on the fly compression when fetching document from the Web and on the fly decompression when sending documents to clients. We show how this technique can reduce paging activity in the DSM and improve overall cache performance.

In this paper, we introduce new analytical models for predicting the performance of World Wide Web (WWW) proxy caches that are distributed over multiple proxy machines under various management protocol assumptions. The purpose of these models is to determinewhich ...

In this paper, we introduce new analytical models for predicting the performance of World Wide Web (WWW) proxy caches that are distributed over multiple proxy machines under various management protocol assumptions. The purpose of these models is to determinewhich distributed cache management (DCM) protocols are to be used for large-scale distributed caches.The accuracy, and usefulness, of our models is assessed by comparing the performance predicted by the models with measurements from real system in operation. We run tests with different values of various parameters that define behavior of distributed cache, communication protocol, DCM protocol, and application.

Terminal's latency, connectivity, energy and memory are the main characteristics of today's mobile environments whose performance may be improved by caching. In this paper, we present an adaptive scheme for mobile Web data caching, which accounts for ...

Terminal's latency, connectivity, energy and memory are the main characteristics of today's mobile environments whose performance may be improved by caching. In this paper, we present an adaptive scheme for mobile Web data caching, which accounts for congestion of the wireless network and energy limitation of mobile terminals. Our main design objective is to minimize the energy cost of peer-to-peer communication among mobile terminals so as to allowfor unexpensive Web access when a fixed access point is not available in the communication range of the mobile terminal. We propose a collaborative cache management strategy among mobile terminals interacting via an ad-hoc network. We further provide evaluation of the proposed solution in terms of energy consumption on mobile devices.

There are many mapping schemes proposed in previous research on parallel proxy servers. The operations of these schemes are mainly URL-based, and therefore cannot fully benefit from the new persistent connection feature of HTTP/1.1. In this paper, we ...

There are many mapping schemes proposed in previous research on parallel proxy servers. The operations of these schemes are mainly URL-based, and therefore cannot fully benefit from the new persistent connection feature of HTTP/1.1. In this paper, we propose a site-based mapping scheme that forwards all requests targeting on the same web site to the same proxy server. The scheme then allows the proxy to use a single persistent connection to serve many client requests. The major advantage of the scheme is the reduction in the number of connection establishments. This reduction can save network bandwidth and reduce the user-experienced latency. Simulation results show that the proposed site-based scheme reduces 40%-70% of the connection setups and teardowns when compared to a traditional URL-based mapping scheme.