J. Barrus, R. Waters, and D. Anderson. Locales and beacons: Efficient and precise support for multiuser virtual environments. In VRAIS, pages 204-- 212, 1996.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....Ideally network traffic should be almost constant or grow near linearly with the number of users. Usually, not all the data in the CVE environment would be relevant to a particular user at a given time. This suggests the idea of partitioning the environment into regions (or zones, locales, auras) [1,8,9] that may either be fixed or bound to moving avatars. Events and actions in remote zones need not be distributed and remote objects need not be visualized or might be visualized at a coarse grain level. Most of the traffic is isolated within zones. 3. Ownership: A multi user CVE world is subject ....

J.W. Barms, R.C. Waters, D.B. Anderson, Locales and Beacons: Efficient and Precise Support for Large Multi-User Environments, in: IEEE Virtual Reality Annual International Symposium, IEEE Computer Society Press, March 1996, pp. 204 213.

....Virtual Environment with Virtual Humans (snapshot from Virtual Life Network [27] 6. 1 Principles of Networked Collaborative Virtual Environments Networked Collaborative Virtual Environments have been a hot topic of research for several years now, and a number of working systems exist [22], 23] 24] 25] 26] 27] They differ largely in networking solutions, number of users supported, interaction capabilities and application scope, but share the same basic principle illustrated in Figure 15. Each workstation has a copy of the virtual environment. The user can move within the ....

Barrus J. W., Waters R. C., Anderson D. B., "Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments", Proceedings of IEEE VRAIS, 1996.

....a centralized database. Since all writes must go through this database, concurrent operations need not be explicitly coordinated; serialization is automatic. Universal Worlds is a proposal whose authors include the researchers at Mitsubishi Electronic Research Labs who worked on SPLINE (See e.g. [2, 3]) It has emerged as one of the leading contenders for a standard infrastructure supporting VR over the Internet. As do many of its proprietary peers, it uses a fully replicated database at each site involved in a VR session. However, writes to each object in the database are centralized only ....

J. Barrus, R. Waters, and D. Anderson. Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments. Mit17 subishi Electronic Research Laboratories, Tech Report TR--95--16, November, 1995.

....avatars, and where they can communicate. The game in neither real time nor distributed. Each participant is connected to a game server using a TCP IP connection. But it is interesting to see the commercial success of this game, where up to 150 participants connect to the same session. Spline [17][18] is a virtual distributed interactive world with 3D animation and spoken interaction. Spline has a distributed architecture which is based on the DIS standard. Most of the effort in Spline has been done on flow synchronization. But the communication architecture is not using the Internet protocol ....

J. W. Barrus, R. C. Waters and D. B. Anderson. " Locales and Beacons: Efficient and precise Support for Large Scale Multiuser Virtual Environments". IEEE Virtual reality Annual International Symposium. Santa Clara (CA). March 1996.

....example [15] But all commercial on line games available to date still use client server architectures based on TCP transmission, simply because this is the only technology fully available and stable on the Internet today. Additionally, closely related works include the following: Spline [17][18] is a virtual distributed interactive world with 3D animation and spoken interaction. Spline has a distributed architecture which is based on the DIS standard. Most of the effort in Spline has been done on local flow synchronization. But there is no distributed synchronization mechanism to deal ....

....close future. If a potential collision is detected, specific ADUs will be sent to other entities to announce the collision. Session management in subgroups of participants. Dividing a session into subgroups is necessary in order to increase the scalability and the consistency of applications [18]. Extension of MiMaze with synchronized 3D Virtual Reality Modeling Language (VRML) objects, video scenes (MPEG4) and 3D spatial audio (that need a higher clock resolution [19] will also be a necessary step to increase the complexity of the application. MiMaze is available for evaluation on the ....

J. W. Barrus, R. C. Waters and D. B. Anderson. "Locales and Beacons: Efficient and precise Support for Large Scale Multiuser Virtual Environments". IEEE Virtual Reality Annual International Symposium. Santa Clara (CA). March 1996.

....We investigate two grouping strategies: cell based grouping and entitybased grouping. Our goal is to understand the tradeoffs between grouping overhead and communication overhead and compare the cost of both strategies under various conditions. 1. Introduction In a distributed multi user game [1, 2], several players move and interact in a virtual space, exchanging information amongst themselves over a network. In these systems, entities (e.g. avatars, tanks, monsters) need to communicate information about their states (e.g. change of color, position or shape) to other entities. One ....

J. W. Barrus, R. C. Waters, and D. B. Anderson, "Locales and beacons: Efficient and precise support for large multi-user virtual environments," Tech. Rep. TR96-02a, Mitsubishi Electric Research Laboratory, Cambridge, MA, 1996. http://www.merl.com/reports/TR96-02a/index.html.

....for learning virtual environments to offer educational services to the users in a sufficient way. To realize this, both a learning virtual environment architecture and a suitable protocol should be specified. 3. Architecture for learning virtual environments Many SVEs have been proposed [1], 2] 4] 7] and [15] These SVEs uses different network architectures that have been categorized at [4] Having in mind the existing networking technologies and models, their advantages and disadvantages as well as the goals and the limitations that an educational system points in the design, ....

BARRUS ,J. W., WATERS, R.C., ANDERSON, D.B., Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments, Proceedings of the IEEE VRAIS'96, IEEE Computer Society Press, Las Alamitos, CA, March 1996.

....By the definition of the Mu3D protocol in previous sections, local copies will be updated by sending the changes encapsulated in update messages. To maintain the consistency we must avoid possible conflicts that can appear when two or more users intend to modify the same region of the scene [Atti94, Awer97, Barr96, Feke95]. We define the following selection policy: 1. We allow a user to modify only selected objects. The selection of an object involves the locking of the VRML sub tree under the selected 109 node. During the period the object is selected, no other user can select such object (Figure 5.5) 2. An ....

Barrus J. W., Waters R. C., Anderson D. B. "Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments." Proceedings of the IEEE VRAIS'96 Conference, IEEE Computer Society Press, Los Alamitos, CA, March 1996.

....the network support until we had a better understanding about what the renderers look like and how they interact. We are planning on first implementing simple network support that is fully connected, but hope to add a network renderer with more sophisticated networking, for example SPLINE [1]. Support for trackers is very rudimentary and needs to be improved. We are still thinking about an intuitive method for the user to add transmitters and receivers for tracking to an environment and have them arbitrarily oriented and located. We are also planning on adding more file readers to the ....

Barrus, J.W., Waters, R.C. and Anderson, D.B., Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments, IEEE Virtual Reality Annual International Symposium, 1996, Santa Clara, California, pp. 204-213.

....and control overhead for distributed multi user games. Keywords: Distributed multi user game, multicast, cell based, entity based, grouping strategy This work is supported in part by a research grant from NSF under contract number NCR 9628379. 1 Introduction In a distributed multi user game [1, 2], several players move and interact in a virtual space, exchanging information amongst themselves over a network. In these systems, entities (e.g. avatars, tanks, monsters) need to communicate information about their states (e.g. change of color, position or shape) to other entities. One ....

J. W. Barrus, R. C. Waters, and D. B. Anderson, "Locales and beacons: Efficient and precise support for large multi-user virtual environments," Tech. Rep. TR96-02a, Mitsubishi Electric Research Laboratory, Cambridge, MA, 1996. http://www.merl.com/reports/TR96-02a/index.html.

....behaviors, as performed by tanks, planes, and missiles, but it is not clear if this technique is useful for communicating non deterministic motions, such as head, hand, or other body movements. An additional technique used to reduce message traffic, that can be found in the NPSNET [16] and SPLINE [3] systems, is through the use of different multicast destination addresses for spatial areas. A user task process only sends its new state to the multicast destination of the area it is located in, and only listens to multicast addresses representing areas close to the user, or can be seen by the ....

Barrus, J. W., Waters, R. C., and Anderson, D. B. Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments. Proc. of the IEEE VRAIS `96, Santa Clara, CA, Apr. 1996, pp. 204-213.

....the speed of light becomes a hard limit. A system like VENUS can cover a wide geographical area, but will be limited in its performance by the high latency experienced when users are physically spread out over different continents. One of the problems with many of the previous VE ideas (e.g. [1]) is that casual browsing is difficult. A user usually has to know the exact address of a particular object user to find them. This is due to the limited amount of information available to all users typically, update information is only available for objects located within a small distance of ....

Barrus, J. W., et. al. Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments. Technical Report TR95-16a, Mitsubishi Electric Research Laboratory, August 1996.

....diagnostics, virtual surgery for training) distance learning training, virtual studio set with networked media integration, virtual travel agency. Networked Virtual Environments (NVEs) have been an active area of research for several years now, and a number of working systems exist [4, 5, 6, 7, 8, 9]. They differ largely in networking solutions, number of users supported, interaction capabilities and application [10] but share the same basic principle. Although NVEs have been around as a topic of research for quite some time, in most of the existing systems the embodiments are fairly simple, ....

.... have been around as a topic of research for quite some time, in most of the existing systems the embodiments are fairly simple, ranging from primitive cube like appearances [11] non articulated human like or cartoon like avatars [12] to articulated body representations using rigid body segments [4, 5]. Ohya et al. 7] report the use of human representations with animated bodies and faces in a virtual teleconferencing application. The realism in participant representation involves two elements: believable appearance and realistic movements. Realism becomes even more important in multi user ....

Barrus JW, Waters RC, Anderson DB (1996) Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments, Proc. IEEE VRAIS, pp. 204-213.

....Virtual Environments, Virtual Humans, Autonomous Behaviors, Virtual Life 1. Introduction Networked Collaborative Virtual Environments (NCVEs) the systems that allow geographically distant users to interact in a shared virtual environment, have been an active research area for several years [Barrus96, Capin97, Carlsson93, Macedonia94, Ohya95, Pandzic97, Singh95]. For many applications, ranging from games to teleshopping or education, it is useful to include autonomous virtual actors in the virtual environment. These computer controlled, seemingly autonomous creatures would inhabit the virtual worlds, make them more interesting, help users to find their ....

Barrus J. W., Waters R. C., Anderson D. B., "Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments", Proceedings of IEEE VRAIS, 1996.

....a certain level, or the owner can simply refuse any new connection requests. The uplink server does not need to be involved in this process it does not even need to know about the load on a particular object owner. 3. 5 Accessibility One of the problems with many of the proposed VE ideas (e.g. [Barr]) is that casual browsing is difficult. A user usually has to know the exact address of a particular object user to find them. This is due to the limited amount of information available to all users typically, update information is only available for objects located within a small distance of ....

J. W. Barrus, et. al., Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments, Mitsubishi Electric Research Laboratory Technical Report TR95-16a. August 1996.

....to talk or at least write to each other. Although Networked Collaborative Virtual Environments have been around as a topic of research for quite some time, in most of the existing systems the communication between participants is restricted to text messages and or to audio communication [Barrus96] Macedonia94] Singh95] The DIVE system [Carlsson93] includes a means of gestural communication by choosing some predefined gestures. The natural human communication is richer than this. Facial expressions, lip movement, body postures and gestures all play an important role in our everyday ....

Barrus J. W., Waters R. C., Anderson D. B., "Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments", Proceedings of IEEE VRAIS, 1996.

....facial parts and later combined to generate a talking head. They focused to reduce the number of samples that are needed and photo realistic movements of lips. 2.3. Shared Virtual World There have been numerous works being done on the topic of shared virtual environments. In most of these works [23][24] 25] each user is represented by a fairly simple embodiment, ranging from cube like appearances, non articulated human like or cartoon like avatars to articulated body representations using rigid body segments. In the work of Pandzic et al. 26] a fully articulated body with skin ....

Barrus J. W., Waters R. C., Anderson D. B., "Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments", Proceedings of IEEE VRAIS, 1996.

....certain level, or the owner can simply refuse any new connection requests. The uplink server does not need to be involved in this process it does not even need to know about the load on a particular object owner. 6 4. 2 Accessibility One of the problems with many of the proposed VE ideas (e.g. [Barr]) is that casual browsing is difficult. A user usually has to know the exact address of a particular object user to find them. This is due to the limited amount of information available to all users typically, update information is only available for objects located within a small distance of ....

J. W. Barrus, et. al., Locales and Beacons: Efficient and Precise Support for Large MultiUser Virtual Environments, Mitsubishi Electric Research Laboratory Technical Report TR9516a. August 1996.

....of the message passing among these components is accomplished via a communications bus using a message protocol called TScript. The overall system architecture, illustrated in Figure 7, is similar in some ways to other virtual environment architectures such as SIMNET (Calvin et al. 1993) and Spline (Barrus et al. 1996), in that it provides a common interface so that multiple applications can share access to a virtual environment over a network. One major difference is that multiple threads of interaction can take place at the same time, each using a different set of messages. For example, one set of messages is ....

Barrus, J.W., Waters, R.C., and Anderson, D.B., 1996. Locales and beacons: Efficient and precise support for large multi-user virtual environments. Proceedings of the IEEE Virtual Reality Annual International Symposium, pp. 204-213. IEEE Computer Society Press.

....provides a scalable network architecture for large scale distributed virtual worlds. We will show how it is used within our current prototype to realize a distributed multi user virtual environment. 1. Introduction Several networked virtual environments have been developed during the last years [2] [3] 8] 15] However most shared virtual environments were limited in one or several ways: either they were restricted to a certain application area, or they were restricted to particular (often high performance) networks, or they did not support a large number of users. Future VR applications ....

J. W. Barrus, R.C. Waters, D.B. Anderson, "Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments," Proceedings of the IEEE VRAIS'96, IEEE Computer Society Press, Las Alamitos, CA, March 1996.

....of networking, database and graphics capabilities. This vast range makes the rapid construction of complex CVEs difficult. Current attempts at building networking and database architectures for CVEs have resulted in ad hoc solutions that are specifically designed to solve a small range of problems[14, 2, 3, 20, 15, 23]. CAVERNsoft is a software architecture that attempts to be cognizant of the diverse human factors, networking and database issues that are involved in supporting CVR. Its main goal is to explore the problem of supporting persistent CVEs for collaborative, education, and scientific and engineering ....

....This topology distributes the database amongst multiple servers. Clients connect to the appropriate server as needed. A classic approach is to bind the servers to unique multicast addresses. Clients then subscribe to different multicast addresses to listen to broadcasts from the servers[2, 8]. 3.6 Synchronous and Asynchronous Collaboration The main focus of most CVR applications has been on synchronous collaboration. That is, all participants are working together in the environment at the same time. However in trans global collaborations the timezone differences make routine ....

BARRUS, J. W., WATERS, R. C., AND ANDERSON, D. B. Locales and beacons: Efficient and precise support for large multi-user virtual environments. In Proceedings of the Virtual Reality Annual International Symposium. VRAIS'96 (March 1996), IEEE Computer Society, IEEE, pp. 204-213.

....a network can slow down the interaction of the individual user with the shared world in an unreasonable way. On the other hand, the user usually realizes only some parts of his or her surrounding. A solution for this problem is the subdivision of large virtual worlds into several regions or zones [4] [10] 20] and to link several worlds together by mechanisms which do not disturb the user during navigation. Only those parts of the virtual world currently visible to the user require to receive updates on their contents. By that, the amount of required network messages can be reduced ....

J. W. Barrus, R.C. Waters, D.B. Anderson. Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments, Proceedings of the IEEE VRAIS'96 Conference, IEEE Computer Society Press, Las Alamitos, CA, March 1996.

....The problems which have to be solved include the partitioning of the world and the determination of the visible cells for each participant. Additionally a suitable support for partitioned shared virtual worlds has to be provided by the network architecture. A number of approaches to realize cells [2] [11] already exist. However, the area of interest manager (AOIM) 17] as used in an extension of NPSNET [21] is the only approach so far making use of individual multicast addresses for each cell. In this approach the virtual world is subdivided into hexagonal cells and the AOIM manages the ....

J. W. Barrus, R.C. Waters, D.B. Anderson. Locales and Beacons: Efficient and Precise Support for Large MultiUser Virtual Environments, Proceedings of the IEEE VRAIS'96 Conference, IEEE Computer Society Press, Las Alamitos, CA, March 1996.

....local hexagon it is in, while at the same time subscribing to many surrounding hexagons via their multicast groups. This approach, while not exact, works well when entities are distributed evenly within the virtual environment, but fails if all entities are clumped within the same cell. In Spline [2], the world is broken up into Locales which can be any size or shape. This allows the designer of the environment to partition the world so as to try and avoid this clumping problem. Although this helps, clumping can still occur because the designer can never know in advance how many entities ....

Barrus, J.W., R.C. Waters, and D.B. Anderson, Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments. 1996, Mitsubishi Electric Information Technology Center America. http://www.merl.com/reports/TR95-16a

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Barrus J.W., Waters R.C., Anderson D.B. (1996) "Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments", Proc. VRAIS 96, Santa Clara CA, March 1996, pp 204--- 213.

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J. Barrus, R. Waters, and D. Anderson. Locales and beacons: Efficient and precise support for multiuser virtual environments. In VRAIS, pages 204-- 212, 1996.

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Barrus, J.W.; Waters, R.C. and Anderson, D.B. (1996) "Locales and Beacons: Efficient and Precise Support for Large Multi-User Virtual Environments", Mitsubishi Electric Research Laboratory TR-95-016a.

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J. W. Barrus, R. C. Waters, and D. B. Anderson. Locales and Beacons : Efficient and Precise Support for Large MultiUser Virtual Environment. Technical report, Mitsubishi Electric Research Laboratory, August 1996.

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J.W. Barrus, R.C. Waters, D.B. Anderson, Locales and Beacons: Efficient and Precise Support for Large MultiUser Virtual Environments, IEEE Virtual Reality Annual International Symposium, IEEE Computer Society Press, Los Alamitos CA, 1996.

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Barrus, J.W., Waters, R.C., Anderson, D.B. Locales and beacons: efficient and precise support for large multi-user virtual environments. Proceedings of 1996 IEEE Virtual Reality Annual International Symposium (VRAIS'96), pp. 204-213.

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Barrus J. W., Waters R. C., Anderson D. B., "Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments", Proceedings of IEEE VRAIS, 1996.

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Barrus J. W., Waters R. C., Anderson D. B., "Locales and Beacons: Efficient and Precise Support For Large Multi-User Virtual Environments", Proceedings of IEEE VRAIS, 1996.

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