J. Leigh, A. E. Johnson, and T. A. DeFanti. Cavern: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. 2(2), 1997.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....well. Therefore concurrency control is a key factor to maintaining a consistent state among replicas. Most existing distributed virtual environment systems adopt simple pessimistic locking concurrency control. The pessimistic scheme allows only a user with a lock to interact with a target object [2, 3, 5, 10, 14]. It is simple and supports strong consistency. Its drawback is that it may induce an ownership transfer delay due network latency as communication delay becomes high. Optimistic concurrency control and predictionbased concurrency control were proposed to provide the maximum interaction ....

....approach. The section 4 describes the enhanced scheme in detail. In section 5, the performance results are presented. Conclusion follows in section 6. 2. RELATED WORKS In this section, we describe approaches taken in existing networked virtual environments. DIVE [2] SPLINE [14] CAVERNsoft [5], Virtual Society [3] and Bricknet [10] adopted a pessimistic concurrency control scheme. The first three systems take a distributed approach in terms of a lock passing while the last two systems do a centralized approach. Only a user with a lock can manipulate the object data and them to other ....

J. Leigh, A. Johnson, T. DeFanti, "CAVERN: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments," Journal of Virtual Reality Research, Development and Applications, the Virtual Reality Society, Vol. 2.2, 1997, pp. 217-237.

....networked audio streams, and how many sound sources can be spatialized in real time without dedicated DSP hardware. The DIVA system provides sophisticated synthesis and spatialization algorithms [14] Its high quality spatialization however requires offline processing. The CAVERNSoft G2 toolkit [19] includes tools for streaming audio data over the network, however, it does not provide support for spatialization. 3D Localization. There are two basic approaches for localizing sound sources: Volume panning with or without crosstalk cancellation [22] and filtering with a head related transfer ....

J. Leigh, A. E. Johnson, and T. A. DeFanti. CAVERN: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Journal of Virtual Reality Research, Development and tpplications, 2(2):217-237, December 1997. The Virtual Reality Society.

....usage information for the purpose of accounting, payment, and or limiting of resource usage by community members. Collaboratory services support the coordinated exchange of information within potentially large user communities, whether synchronously or asynchronously. Examples are CAVERNsoft [28, 47], Access Grid [23] and commodity groupware systems. These examples illustrate the wide variety of Collective layer protocols and services that are encountered in practice. Notice that while Resource layer protocols must be general in nature and are widely deployed, Collective layer protocols span ....

Leigh, J., Johnson, A. and DeFanti, T.A. CAVERN: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments. Virtual Reality: Research, Development and Applications, 2(2):217-237. 1997.

....Section six presents an overview of alternative approaches and future extensions to the NOMAD framework. We finish the paper by presenting our conclusions in section seven. 2. Related Work With the recent exception of [20,3] VE toolkits such as Maverik [13] DIVE [14] MASSIVE [15] and CAVERN [16] have avoided exploiting the CORBA architecture in the development of DVE applications. Early versions of the CORBA specification were unsuitable for supporting the distribution and management of data within distributed interactive graphical applications for a number of reasons. Firstly, to ....

....and research into real time CORBA [7,8,9,10,21] CORBA now represents a technology mature enough to provide much of the functionality required in DVE development. Typically, most DVE applications and DVE development toolkits use distributed callbacks extensively as a method of event notification [1,13,14,15,16]. Distributed callbacks are often not straightforward to program and have some inherent problems regarding object reference equality, persistence, callback failure and notification scalability [17] CORBA provides two object services that support event notification, the event service [4] and the ....

Leigh, J., Johnson, A., DeFanti, T., CAVERN: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments, in Virtual Reality: Research, Development and Applications, Vol 2.2, 1997

....pessimistic or optimistic concurrency control scheme. The pessimistic scheme blocks a user until a lock request for an object is granted and then allows him to manipulate the object. It is simple and guarantees consistency [2] This scheme is used in many existing virtual environment systems [3, 6, 9, 13, 17]. However, as communication delay becomes high, the interactions of users may be interrupted. The optimistic scheme allows users to update objects without conflict checks with other users. However, when conflicts occur, a repair must be done. This not only makes systems complex but also users ....

....on object basis and only a user having a token can manipulate an object. To avoid conflicts, other users are blocked until the token is granted. However, blocking a user is not desirable since it makes the user difficult to do other activities and interrupts the user s interaction. CAVERNsoft [9] deals with concurrency control in two ways. One is to employee no conflict resolution scheme for human natural interaction performance. The other is to lock and unlock an object. Unlike DIVE, locking calls are non blocking to prevent real time applications from stalling when attempting to acquire ....

J. Leigh, A.E. Johnson, T.A. DeFanti, "CAVERN: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments", Journal of Virtual Reality Research, Development and Applications, the Virtual Reality Society, Vol. 2.2, 1997, pp. 217-237.

....for Hughes Training Inc. and NASA [10] This system provided users at three remote sites the ability to move and collaborate in a shared model of the international space station. A key component to effective collaborative virtual environments is the communication infrastructure. CAVERNSoft [9] from UIC EVL is a software library that allows VR developers to share information between their applications. This is a hybrid system that combines a distributed shared memory model with distributed database technology and real time networking technology. This allows objects manipulated by one ....

Leigh, J., Johnson, A., DeFanti, T.A., CAVERN: a Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments, Journal of Virtual Reality Research, Development and Applications.

....the programming models and services used by application developers. Today s small population of grid tool developers (e.g. the developers of Condor [41] Nimrod [1] NEOS [17] NetSolve [11] Horus [68] grid enabled implementations of the Message Passing Interface (MPI) 27] and CAVERN [39]) must build their tools on a very narrow foundation, comprising little more than the Internet Protocol. We envision that future grid systems will provide a richer set of basic services, hence making it possible to build more sophisticated and robust tools. We discuss the nature and implementation ....

Jason Leigh, Andrew Johnson, and Thomas A. DeFanti. CAVERN: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Virtual Reality: Research, Development and Applications, 2(2):217--237, December 1997.

....with up to six back projection units. Distributed versions of SIDs allow users to interact with remote collaborators in telecollaboration applications. Those systems usually integrate video based human avatars, possibly enhanced with pre constructed geometric models, into the virtual environment [4, 2, 5]. A different approach to constructing dedicated SIDs, is to integrate the projection units and the projection surfaces directly into existing office environments. The office of the future [7] is a good example. Full integration of human collaborators into SID environments, as opposed to using ....

J. Leigh, A. E. Johnson, and T. A. DeFanti. "CAVERN: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments." Journal of Virtual Reality Research, Development and Applications, 2(2):217--237, Dec. 1997.

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Leigh, J., Johnson, A., DeFanti, T., CAVERN: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments. In Virtual Reality: Research, Development and Applications, Vol 2.2, December 1997 (1996), Pp 217-237.

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Leigh, J., Johnson, A.E. and DeFanti, T.A. CAVERN: a distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Journal of Virtual Reality Research, Development and Applications, 2(2):217-237, 1997.

....design, education and training, scientific visualization, and computational steering. Our goal is to make these systems convenient, so that scientists and designers can do real work within these shared environments without having to worry about how the collaboration is sustained. CAVERNsoft G1 [13] was our previous attempt to provide a system to rapidly generate tele immersive applications, and retrofit a legacy of non collaborative VR applications, with tele immersive capabilities. Other similar toolkits available, academically or commercially, including DIVE [2] NPSNET[16] ....

....viability of these ideas, we developed a proof of concept (CAVERNsoft G0) in September 1996. Additional capabilities such as greater reliability and the ability to share data over a variety of network connections simultaneously, culminated in the first release of CAVERNsoft (G1) in September 1997 [13]. G1 was unique in a number of ways. Firstly, it broke the traditional model of DSMs by allowing clients to share information transparently over both reliable and unreliable links. Secondly, G1 was client and server symmetric. That is, a client program was indistinguishable from a server program. ....

Leigh, J., Johnson, A. E. and DeFanti, T. A., "CAVERN: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments," Journal of Virtual Reality Research, Development and Applications, 2(2):217-237, 1997.

....be de ned by a programmer, such as a user s button press and proximity. Di erent classes recognize di erent messages. 2. 3 Network Support for V mail The clients communicate with the server using CAVERNsoft[6] which facilitates the construction of persistent collaborative virtual environments [5]. CAVERNsoft manages distributed data stores. The data distribution between a client and a server application is realized by the Information Request Broker(IRB) The IRB is a repository of persistent data that is accessible by a variety of networking interfaces. It emulates a persistent ....

J. Leigh, A. E.Johnson, and T. A. DeFanti. CAV ERN : A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Journal of Virtual Reality Research, 2.2:217-237, December 1997.

....applications. Each focus will naturally contribute results that will feedback into the other foci. Figure 1. CAVERNsoft Within the limitations of this paper we will provide an overview of two aspects of the CAVERNsoft effort; the tools, and the applications being developed. CAVERNsoft[4, 5] is an ongoing effort to develop a TI infrastructure that supports the rapid creation of new tele immersive applications, and the retrofitting of previously non collaborative VR applications with tele immersive capabilities. The primary difference between CAVERNsoft and previous approaches is its ....

J. Leigh, A. E. Johnson, and T. A. DeFanti. CAVERN: a distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Journal of Virtual Reality Research, Development and Applications, 2(2):217--237, 1997.

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J. Leigh, A. Johnson, and T. DeFanti, "Cavern: A Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments," Virtual Reality: Research, Development, and Applications, Vol. 2, No. 2, Dec. 1997, pp. 217-237.

....CAVERNsoft [http: www.evl.uic.edu cavern] is the systematic software architecture for the CAVE TM Research Network (CAVERN) an alliance of research and industrial institutions equipped with CAVEs, ImmersaDesks TM, and high performance computing resources, interconnected by high speed networks. [6][7] CAVERNsoft focuses on tele immersion the union of networked virtual reality and video in the context of significant computing and data mining and supports collaborative virtual reality in design, training, education, scientific visualization, and computational steering. Developed at EVL, ....

J. Leigh, A. Johnson, and T. DeFanti, "CAVERN: Distributed Architecture for Supporting Scalable Persistence and Interoperability in Collaborative Virtual Environments," Journal of Virtual Reality Research, Development and Applications, Virtual Reality Society, Vol. 2, No. 2, December 1997, pp. 217-237.

....need for human involvement in the resource selection process) and communication (using Globus communication services to access multicast and quality of service mechanisms, hence improving scalability and simulation performance) 3. CAVERNsoft The second application that we consider is CAVERNsoft [20], a software infrastructure designed to support the rapid development of teleimmersive applications. In teleimmersion, immersive virtual reality environments are used over networks to provide shared access to simulated virtual spaces for design, collaboration, entertainment, education, and so ....

....a software infrastructure designed to support the rapid development of teleimmersive applications. In teleimmersion, immersive virtual reality environments are used over networks to provide shared access to simulated virtual spaces for design, collaboration, entertainment, education, and so forth [20, 8] The producers and consumers of the virtual environment, as well as the datasets and simulations on which the virtual space is based, are frequently geographically distributed, placing heavy demands on distributed computing support. For example CAVERNsoft is the underlying data distribution ....

J. Leigh, A. Johnson, and T. A. DeFanti. CAVERN: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Virtual Reality: Research, Development and Applications, 2(2):217--237, December 1997.

....supports the rapid creation of new Tele Immersive applications, and eases the retrofitting of previously non collaborative VR applications with Tele Immersive capabilities. A full discussion of CAVERNsoft is beyond the scope of this short paper. This can be found by reading the following papers: [5, 4, 3]. This paper will describe the lessons learned in adapting the Visualization Toolkit to a multi pipe VR environment and the work in CAVERNsoft to provide a re usable software tool called LIMBO that offers application developers a template for building tele immersive applications. In addition it ....

Jason Leigh, Andrew E. Johnson, and Thomas A. DeFanti. CAVERN: a distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Journal of Virtual Reality Research, Development and Applications, 2(2):217--237, 1997.

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J. Leigh, A. E. Johnson, and T. A. DeFanti. Cavern: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. 2(2), 1997.

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J. Leigh, A. E. Johnson, and T. DeFanti, "Cavern: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments," Journal of Virtual Reality Research, Development and Applications, vol. 2, no. 2, pp. 217--237, 1996.

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J. Leigh, A. Johnson, and T. DeFanti. Cavern: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments. Virtual Reality: Research, Development and Applications, 2(2):217--237, 1997.

No context found.

J. Leigh, A.E. Johnson, and T.A. DeFanti. "CAVERN: A distributed architecture for supporting scalable persistence and interoperability in collaborative virtual environments." Journal of Virtual Reality Research, Development and Applications, 2(2), pp. 217-237, Dec. 1997.

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