Voice over Internet Protocol (VoIP) utilizes the Internet for voice communication. VoIP has a problem that a voice gap occasionally happens according to a delay spike. A voice gap caused by a delay spike is longer than 500 milliseconds. Voice gap compensation methods have been proposed before now, but they are all only for short term gaps. No compensation method for long term voice gaps was proposed, because it was too difficult to compensate several phonemes. Our proposed method is for long term voice gaps. When a spike delay happens and next packet does not arrive, the receiver stops replaying voice and repeats the talk-spurt from the beginning instead of replaying next packet after the voice gap. This method can transmit the meaning of a sentence clearly, because automatic speech repetition simulates speech repair which often occurs in normal conversation. Humans are accustomed to this speech repair. This method can preserve naturalness as well, because it changes voice gaps into speech repetition. And the listener has little awareness of speech repetition compensation. We implemented the IP telephony system equipped with speech repetition compensation and also evaluated this method. As the result, we could ensure the usefulness of this method.

Movies edited by amateurs are likely to be a sequence of monotonous scenes, where people record video from a single direction, and use video from a single camcorder when editing video. We developed VideoBlocks, a Web-based video editing system. In our system, video clips are collected from multi-users' camcorders via the Internet and shared among the users. The system allows users to easily use other users' video clips, each of which is spontaneously videotaped using different digital video camcorders. VideoBlocks provides the capability to extract the date and time information of the video-recording from the digital video cameras, and automatically synchronize them. Through evaluations of the system, we determined the effectiveness of the system.

In this paper, we propose the broadcasting data structure that can clip the requested scene or information in the TV program, and that can reconstitute the TV program depending on the review environment or the purpose. As a result, this mechanism enables users to use the clipped broadcasting contents for various purposes.

Visual shared workspaces will be always staying on users' screens in the near future. Users will be moving frequently between their personal workspaces for personal and asynchronous work and shared workspaces for communication and synchronous cooperation. Also the system should supports users' everyday awareness of co-workers. For supporting such situation, this paper proposes a new technique to visualize workspaces as a set of layered virtual screens in three-dimensional space. In this way, groups' shared spaces are shown as background of users' personal spaces like as looking from a top personal layer down to a bottom public layer. In conventional groupware, user's workspace is divided into some shared spaces and a personal space to show all of them simultaneously, so the size of the personal space is very restricted. This layered perspective visualization alleviates this problem and also supports users' awareness by always showing shared spaces in background.

Nowadays in many enterprises, for the purpose of efficiency improvement and the automation of the business, the workflow management system of the business process is coming into wide use. However, an individual workflow management system is introduced into each organization so the workflow system is effective as a business support inside a single organization, but it is difficult to apply this management system to coordinate business among more than two organizations. We propose Interworkflow system which coordinates each workflow system among multiple organizations. The Interworkflow system consists of three sub-systems and has a user friendly interface. We report on the fact that we have constructed an actual Interworkflow system that coordinates multiple workflow systems and confirm that it functioned effectively.

In this paper, we assume that there will be two networks, the next-generation public network and the Internet, as the future information network infrastructure, and we propose the interworking architecture that allows users to utilize services on the next-generation public network from the Internet environment. The proposed architecture is constructed on the open distributed processing environment, based on TINA. We also constructed a platform, PLUS-TINA, especially for making use of services on the TINA-based public network from any Internet environment.

Article Integration of face-to-face and video-mediated meetings: HERMES Share on Authors: Tomoo Inoue Department of Information and Computer Science, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 Japan Department of Information and Computer Science, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 JapanView Profile , Ken-ichi Okada Department of Information and Computer Science, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 Japan Department of Information and Computer Science, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 JapanView Profile , Yutaka Matsushita Department of Information and Computer Science, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 Japan Department of Information and Computer Science, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 JapanView Profile Authors Info & Claims GROUP '97: Proceedings of the international ACM SIGGROUP conference on Supporting group work: the integration challengeNovember 1997 Pages 405–414https://doi.org/10.1145/266838.267361Online:16 November 1997Publication History 10citation465DownloadsMetricsTotal Citations10Total Downloads465Last 12 Months5Last 6 weeks1 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteGet Access

Portable computers can be connected to a network by wireless communication while the user is moving. Users can enjoy this capability and use services on a computer network in any place and at any time. This new style of computer usage is called "mobile computing". In a mobile computing environment there are some problems which are caused by using wireless interfaces, such as disconnection and inability to connect to the network. Moreover, it is likely that most users operate not only with their portable computers but also with other computers in their office, home and so on. The authors discuss the agent platform which considers these features of mobile computing. This platform is designed in order to cover the shortages of wireless communication, and to provide a platform for agents that support user mobility.

This paper formulates "partition type fuzzy integral" which is a fuzzy integral of functions on a partition of the set of all attributes. The identity of it is the set of intermediate fuzzy integrals between the linear form and the usual multilinear fuzzy integrals. In this fuzzy integral, any combination of attributes in the same macro-attribute yields no interactions, but any set of attributes, each member of which belongs to a distinct macro-attribute, causes an interaction. Therefore, we can extract only the essential interactions from the evaluation process by discovering the best expressive partition. An application to a concrete evaluation problem shows the effectiveness of this model.

This video shows a multiparty videoconferencing system “MAJIC” and a multiparty desktop conferencing system “DesktopMAJIC”. MAJIC is composed of 2 video cameras, 2 video projectors, a one-way transparent screen, and a tilted workstation forming a desk. Life-size video images of participants are projected without boundaries onto a large curved screen as if users in remote locations are sitting around a table attending a meeting together. MAJIC supports gaze awareness and multiple eye-contact among the participants. Moreover, a shared work space is provided at the center, enabling users to carry on a discussion in a manner comparable to face-to-face meetings.

Today, various novel telecommunication systems have been proposed. The idea of a virtual communication space shared by multiple distributed users via networks, so-called cyberspace, has received considerable communication. In cyberspace, there are tremendously many users, on-line services, and much information, and users have great opportunity to encounter all of these. We think the most serious problem in cyberspace is the great risk that a user might miss a chance to get relevant or important information. In this paper, we propose a strategy for auditory browsing to address this problem, using a spatial sound interface. We implemented VCP (Virtual Cocktail Party), an experimental system for achieving efficient and flexible telecommunication and data retrieval, which takes advantage of human auditory capability. This system can support a number of physically separated users in a single shared sound cyberspace and consists of distributed terminals with a spatial sound interface.

The service system which is built on a distributed processing environment (DPE) is becoming one of the most promising techniques for the flexible and rapid introduction of services. We propose a service networking architecture suitable for VoD services based on the TINA compliant model. The applications in this architecture are deployed as units of software managers. Each manager provides a layered view for the effective management and control of the multimedia network resources and services according to the concept of TMN and TINA. For the purpose of flexible service provision to users and effective service introduction by service providers, this architecture proposes the adoption of ad hoc service managers such as a video on demand (VoD) manager and a protocol for transactions between those. This paper also proposes a reference scenario for interworking of the TINA-like model with the WWW environment. The proposed architecture is implemented on a DPE platform that provides various transparencies.

This paper presents a novel standard baseline JPEG compatible still image compression method that allows to flexibly control the decompression quality of regions in image.Therefore, it allows both higher quality of important parts and lower bitrate as a whole, and it reflects the sense of human beings.We use fuzzy technique to determine important regions in the same manner as human beings do, allocate higher bitrate to important regions while lower to the rest parts of image.The paper introduces the important region determination, description, arbitrarily shaped region filling, importance adaptive image compression, decompression, and finally gives experimental results.

This paper addresses a novel networking architecture model on DPE for various multimedia services suitable to high speed networks and for the flexible and rapid introduction of services. In this model, applications are assembled from software "building blocks" which cope with information service and network providers. Each building block provides a layered view, enabling the effective management of multimedia network resources and services according to the concept of TMN and TINA. In this paper, we also propose the use of a directory system and its naming structure for the management of user profiles and session profiles, and a control model of effective multimedia logical device objects that uses a stream process approach. Our model is implemented on a DPE platform that provides various transparencies. For the purpose of flexible service provision to users, this architecture presents ad hoc service building blocks such as a video on demand building block and a CSCW building block.

The paper deals with nonverbal communication in asynchronous networks. It is well known that nonverbal communication plays an important role in interpersonal communication. However, nonverbal communication has not been used in traditional character based network communication until now, yet the need for conveying feelings has increased. Due to the development of multimedia networks, it is thought that nonverbal communication can be valuable for network communication. The research is based on the importance of expressing feelings through nonverbal communication, especially gestures. It has not yet been determined what kind of feelings can be conveyed by gestures so the evaluation of feelings expressed by gestures has been done using animated cartoons. From this, it has been shown that feelings expressed by gestures on display are distinguished in five ways by the Japanese. Furthermore, an evaluation of electronic mail with computer graphics animation has been done as an example of asynchronous network communication. From this, it has been seen that mail with the gestural animation reflects the feelings of its animation. Using gestural animations to convey feelings in asynchronous networks has been suggested.>

Article Free Access Share on Learning from TV programs: application of TV presentation to a videoconferencing system Authors: Tomoo Inoue Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 Japan Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 JapanView Profile , Ken-ichi Okada Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 Japan Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 JapanView Profile , Yutaka Matsushita Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 Japan Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223 JapanView Profile Authors Info & Claims UIST '95: Proceedings of the 8th annual ACM symposium on User interface and software technologyDecember 1995 Pages 147–154https://doi.org/10.1145/215585.215967Published:01 December 1995Publication History 25citation450DownloadsMetricsTotal Citations25Total Downloads450Last 12 Months20Last 6 weeks0 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

Article Free Access Share on An image retrieval system considering subjective perception Authors: Haruhiko Nishiyama Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPAN Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPANView Profile , Sumi Kin Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPAN Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPANView Profile , Teruo Yokoyama Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPAN Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPANView Profile , Yutaka Matsushita Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPAN Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223, JAPANView Profile Authors Info & Claims CHI '94: Proceedings of the SIGCHI Conference on Human Factors in Computing SystemsApril 1994Pages 30–36https://doi.org/10.1145/191666.191685Published:24 April 1994Publication History 6citation446DownloadsMetricsTotal Citations6Total Downloads446Last 12 Months26Last 6 weeks7 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my AlertsNew Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF

The paper presents a networking architecture model for multimedia applications and their flexible management suitable for B-ISDN. In this architecture, the applications are separated by building blocks according to their functionality in a distributed processing environment. This architecture provides a layered view of an effective management of the multimedia network resources and services. Also, we propose a model for managing and controlling multimedia terminal resources. Finally, we discuss interoperability in order to facilitate connections between multimedia network elements.>

In an office working environment, it is very unusual that a worker is engaged in a single task until the task is completed. Generally, multitasking is the norm, so workers will belong to several project groups and work on one of the projects and then, before completing that, switch to another. Focusing on how to manage resources effectively and how to support task performance in an environment in which workers belong to multiple projects, this paper examines the provision of appropriate mechanisms to support collaborative work in the environment. We suggest a method for managing resources which uses a 3-level structure consisting of a sharing level, a working level and a personal level, and we describe the implementation of the Multi-Project Support System which is capable of supporting interrelations among workers, resources and projects.>

This paper describes the design and implementation of MAJIC, a multi-party videoconferencing system that projects life-size video images of participants onto a large curved screen as if users in various locations are attending a meeting together and sitting around a table. MAJIC also supports multiple eye contact among the participants and awareness of the direction of the participants' gaze. Hence, users can carry on a discussion in a manner comparable to face-to-face meetings. We made video-tape recordings of about twenty visitors who used the prototype of MAJIC at the Nikkei Collaboration Fair in Tokyo. Our initial observations based on this experiment are also reported in this paper.

Attention to CSCW has been increasing, resulting in greater needs for secure group communication. In order to realize secure group communication, data which is sent from a member to other members of a group should be encrypted by the cryptographic communication key of the group. We propose an identity-based non-interactive group communication key sharing scheme using smart cards based on the modified copy key (MCK) method. We assume that the smart cards contain the key generators and are secure for tampering. Each user has a smart card and a key generator. A user can generate a group communication key non-interactively with his key generator and the IDs of the other group members using his smart card.>

This paper describes and discusses the modeling of multimedia communication networking architecture suitable to high speed networks such as LAN, B-ISDN, etc. for the flexible management and rapid introduction of services. In this model, the applications are deployed in units of software building blocks called group call server, service control server, resource management server and client agent. Each building block provides a layered view for the effective management of the multimedia network resources and services. In this paper, we propose a service scenario scheme and multimedia logical devices model for the flexible generation and effective management of services, and abstracting the network resources, respectively. Finally, this paper presents an architecture evolution model toward interoperability in a distributed processing environment (DPE). This can be applied for interoperability between multimedia network resources provided by different vendors.>

The number of automobiles is explosively increasing and automobiles have important roles in communities from the viewpoint of transportation. In this situation, the increase in traffic accidents is becoming a serious social problems. Most accidents are caused by the lack of a means of getting information about situations around vehicles. Therefore, the authors propose an inter-vehicle networking method as a means of data exchange. In addition, they propose a variable range sending phase, too. It is able to decrease the number of transmitter-receivers. By using this method, each vehicle can know the positions of neighbor vehicles, the traffic information captured by some other vehicles, and the neighbor node's information such as speed, braking and so on. So this method is well-positioned for the basis of safety and comfortable driving technology. The authors propose a networking method, too. This networking method may be able to broadcast traffic information such as traffic accident information, jam information, and so on.>

The authors designed a procedure-forwarding mechanism and developed an electronic mail system named PilotMail. PilotMail provides the basis of an asynchronous communication environment suitable for group work in which a sender can guide receiver's behavior. Also realized was a communication environment in which speaking and acting are well coordinated on the basis of the integration of the procedure-forwarding mechanism, the structured-mail technologies, and the conversation management mechanism. A prototype system was developed in an Objectworks/Smalltalk environment.>

A self-organizing method of a decentralized LAN is proposed, its characteristics are evaluated by computer simulation based on a simple network model. It is found that this decentralized network self-organizing method can be adopted to established wireless LAN systems by adding a few functions. This method is extremely simple and the functions which each station must have are very few.

This paper describes “Book Window” that we implemented, a window system based on the “book” metaphor, that displays information not by scrolling but by using the animation of paging through. The BookWindow system equips some bookmarks, tabs, etc., by which we can access to an expected page through our requirements. BookWindow can support our work environment which navigates us through information space flexibly, because human beings are quite familiar with “books”.

Time dependent multimedia document (TDMD), a tool that supports human communication under distributed computing environments, is described. TDMD supports various types of communication media, including audio, video, text, graphics, and image. Multimedia presentation is formally defined, and it is shown that, TDMD can be represented uniquely as a tree structure. In the structure, hyperlink information can be included by introducing graphical interface buttons, which are treated the same way as other media. The content information included in a button is its visual appearance as a metaphor and the name of a destination node from which successive presentation begins when the button is selected. By using such link information, several browsing paths can be included in TDMD. Buttons also give viewers control over the speed of a presentation.>

As a media access control (MAC) protocol for integrated services on a high-speed LAN, the distributed priority change (DPC) protocol is proposed. DPC supports synchronous voice/video service and asynchronous data service. To support synchronous service, it is necessary to guarantee periodic access to the network with a small delay variation. This requirement is met by alternating between the synchronous mode and the asynchronous mode. In DPC, there is not central controller and there is no special bit in the token for reservation to realize fair asynchronous data transmission. Performance comparisons with other token ring protocols are presented. It is shown that DPC can achieve higher maximum throughput than other priority protocols using a central controller. DPC can transmit long size data more effectively than the timed token protocol used in FDDI.>

The authors propose a hybrid indoor data network system that uses radio as a transmission medium for the lower layer and uses conventional LAN for the upper, and its distributed dynamic channel assignment scheme in the 15th LCN and other conferences. In this paper indoor radio propagation measurements at 1.2 GHz are presented in order to develop a fading channel model. The system performance is analyzed through computer simulations based on the fading channel model led from the propagation measurements. They adopt the following parameters: the number of radio terminals, the number of channels assigned to each base station, and the volume of traffic in the lower network. The results show that one can reduce the number of channels assigned to each base station without loss of performance under the condition that 10 Mbps CSMA/CD network is used as the upper layer, and 32 Kbps CSMA packet radio network is used as the lower.>

A cryptographic scheme can be used for controlling access to information, since any user who does not have a proper key can not decipher. But for this purpose, a user would have to manage a huge number of keys when he tries to communicate with a lot of people. The practical utilization method of access control by cryptography is discussed. The authors propose a typical organizational structure called hierarchical group oriented structure and go on to propose a hierarchical group oriented key management method (HGK method) based on the multiple keys generated from the combination of pieces. They explain that this method is very desirable in terms of reducing the numbers of keys required for each user in the hierarchical group oriented structure.>

A network system having two layers is proposed. This system uses radio as a transmission medium to the lower layer and a conventional LAN to the upper one. The users of a wireless network enjoy complete freedom from frequent reconfiguration of existing terminal arrangements. However, office buildings present a harsh environment for radio transmission because of numerous reflections from walls, furniture, and even people. A dynamic channel assignment scheme with no host computers is also described. The system performance is analyzed through computer simulations. The results show that 100 remote terminals are accommodated to 25 base stations safely on the conditions that the upper layer is a 10-Mb/s carrier sense multiple access with collision detection (CSMA/CD) network and the lower is a 32-kb/s CSMA packet ratio network.>

In comparison to centralized database systems, distributed database systems have certain advantages depending on the manner in which data are redundantly distributed. These advantages are improvement in response time, better data availability, reduction in transmission cost, etc.

This paper focuses on the concurrency control problem for a distributed database system. A new control philosophy called hierarchical processing structure is proposed. Two different types of the consistency are clearly defined, and the hierarchical processing structure is derived from these consistency types. This structure provides the following features;