We introduce a technique that reduces the number of state savings and the maximum memory needed for the time Warp. We present a technique to determine if an event is safe or not. If an event execution is safe, no stat...
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Lecture-on-Demand (LOD) multimedia presentation technologies among the network are most often used in many communication services. Examples of those applications include video-on demand, interactive TV and the communi...
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ISBN:
(纸本)0769515886
Lecture-on-Demand (LOD) multimedia presentation technologies among the network are most often 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 a web-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, suppose a 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, this very approach is sufficient to the use of distance learning environment.
We extend our previous work on formalizing event orderings using partial order set and its application in space analysis in distributedsimulation. We focus on the time and space trade-off in exploiting event parallel...
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We extend our previous work on formalizing event orderings using partial order set and its application in space analysis in distributedsimulation. We focus on the time and space trade-off in exploiting event parallelism. Event parallelism is divided into inherent (problem) parallelism, event ordering parallelism and effective event parallelism. Firstly, we analyze the performance cost of varying event ordering parallelism on memory requirement in open and closed systems. Secondly, we study the effects of interconnection topology of a physical system on exploitable event ordering parallelism. Measurements were obtained from a time-space analyzer that we have developed.
With distributedsimulation, existing simulations, even from different disciplines, can be reused or made to interoperate. The efficiency of this technique is, however, not firmly established and depends on the abilit...
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With distributedsimulation, existing simulations, even from different disciplines, can be reused or made to interoperate. The efficiency of this technique is, however, not firmly established and depends on the ability to satisfy a number of requirements, especially concerning simulation performance. The performance depends to a large extent on the structure and scaling of architectural components of the simulation execution platform. In this paper, we present an approach to address this problem: the design of models to capture the main characteristics of distributedsimulations, run-time infrastructures and network architectures, and the development of a tool to predict performances. This tool, which is a simulator of HLA simulations, is written using HLA, and is evaluated on three test applications.
Running a large-scale distributedsimulation may need a large amount of computing resources at geographically different locations. These resources may be from different organizations. The simulation may run for a long...
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Running a large-scale distributedsimulation may need a large amount of computing resources at geographically different locations. These resources may be from different organizations. The simulation may run for a long period of time and the availability and amount of computing resources available may change during the course of simulation execution. Therefore, coordinating and managing resources for distributedsimulation to complete the simulation efficiently and effectively is a critical issue. This paper describes a load management system for HLA-based distributedsimulation. The system is constructed on top of a grid computing environment supported by Globus. The overall structure of the system is presented in the paper and how the system saves and restores a federate is also discussed in detail.
The Generic Runtime Infrastructure for distributedsimulation (GRIDS) has been developed to investigate modularity issues in distributedsimulation. It could be argued that although the HLA RTI is a widespread solutio...
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The Generic Runtime Infrastructure for distributedsimulation (GRIDS) has been developed to investigate modularity issues in distributedsimulation. It could be argued that although the HLA RTI is a widespread solution to distributedsimulation, it cannot include all possible services. This paper investigates an approach to extending the distributedsimulation services available in the HLA RTI. One example of this is bridging support for HLA/DIS legacy integration. This paper therefore presents GRIDS, how GRIDS can be used to provide modular service support for the HLA RTI, and a case study on legacy integration to demonstrate our approach.
Many simulations and other applications need to interact seamlessly with distributed data resources. The Agent-Based Environment for Linking simulations (ABELS) allows the formation of a dynamic "data and simulat...
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Many simulations and other applications need to interact seamlessly with distributed data resources. The Agent-Based Environment for Linking simulations (ABELS) allows the formation of a dynamic "data and simulation cloud" that links a heterogeneous collection of networked resources. ABELS consists of three major types of components: user entities that serve as data producers and/or consumers, a brokering system for organizing and linking the various participants, and generic local agents that connect simulations and data resources to the cloud of participants. This paper presents the design of the distributed brokering system, which is implemented using Java and Sun Microsystems' Jini technology.
This paper introduces a coloured Petri nets formalism-TCPN-which is suitable for modelling and simulation of complex systems. Novel in TCPN is (i) a timing model which accommodates both unordered and ordered (queue) p...
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This paper introduces a coloured Petri nets formalism-TCPN-which is suitable for modelling and simulation of complex systems. Novel in TCPN is (i) a timing model which accommodates both unordered and ordered (queue) places; (ii) the adoption of Java as the net inscription language. TCPN is supported by a graphical tool-RAINBOW-which allows model design, testing and simulation. A large TCPN model can be split into regions (subnets) whose execution is assigned to different LP/processors of a networked simulator. distributedsimulation relies on TUTW, an agent-based time warp algorithm capable of exploiting temporal uncertainty for improving simulation performance. The paper describes TCPN and its distributed execution kernel. The practical use of TCPN is demonstrated through an example and experimental results.
The High-Level Architecture (HLA) provides a common architecture for distributed modeling and simulation. In its original form, HLA allows a number of simulations to be joined together into a federation using a single...
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The High-Level Architecture (HLA) provides a common architecture for distributed modeling and simulation. In its original form, HLA allows a number of simulations to be joined together into a federation using a single run time infrastructure. Recently there has been interest in joining multiple federations together using a mediating unit, called an HLA "bridge." This paper presents the results of an in-depth study of the feasibility of an HLA bridge in the context of the current HLA interface specification. Problems and solutions are discussed and illustrated using particular HLA services.
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