The partitioning of complex processor models on the gate and register-transfer level for parallel functional simulation based on the clock-cycle algorithm is considered. We introduce a hierarchical partitioning scheme...
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The partitioning of complex processor models on the gate and register-transfer level for parallel functional simulation based on the clock-cycle algorithm is considered. We introduce a hierarchical partitioning scheme combining various partitioning algorithms in the frame of a competing strategy. Melting together different partitioning results within one level using superpositions we crossover to a mixture of experts one. This approach is improved applying genetic algorithms. In addition we present two new partitioning algorithms both of them taking cones as fundamental units for building partitions.
We describe the TED/C++ implementation of WIPPET, a parallelsimulation testbed for evaluating radio resource management algorithms and wireless transport protocols. Versions 0.3 and 0.4 of the testbed model radio pro...
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We describe the TED/C++ implementation of WIPPET, a parallelsimulation testbed for evaluating radio resource management algorithms and wireless transport protocols. Versions 0.3 and 0.4 of the testbed model radio propagation (long- and short-scale fading and interference) and protocols for integrated radio resource management in mobile wireless voice networks including the standards-based AMPS, NA-TDMA and GSM protocols, and several research-oriented protocol families. We provide parallel performance data verifying that the dominant computational demand due to received signal quality calculation can be partitioned geographically, by orthogonal radio channels, or in a hybrid manner.
Presents a new approach to perform distributed event driven simulation that we have named the 'deblocking event algorithm'. This algorithm adopts the conservative paradigm, but takes into account the structura...
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We present a case study in which we apply parallelsimulation methods and interoperability techniques to network simulations for simulation-based on-line control of military communication networks. The on-line simulat...
ISBN:
(纸本)0769516084
We present a case study in which we apply parallelsimulation methods and interoperability techniques to network simulations for simulation-based on-line control of military communication networks. The on-line simulations model actual military networks, including wired shipboard sub-networks connected via satellite links, and wireless mobile devices. The modeled scenario depicts the communication requirements of an amphibious landing where a complex network connects troops ashore and naval vessels. The simulations use a heterogeneous set of tools, including ns2 models for shipboard wired networks, and GloMoSim models for the wireless devices. In this paper, we document the challenges we encountered in applying parallel and interoperable simulation methods, and describe our solutions. We describe our experiences in addressing the interoperability problems that naturally arose due to the heterogeneity of scenario models. We also present a preliminary study on the scalability of real-time performance of parallel network simulations, which is crucial for on-line simulations. Salient system characteristics of the subject military network scenarios are described for the benefit of exposure to the modeling and simulation research community. Our exercise not only highlights the relevance of parallel and distributedsimulation techniques to an important real-life problem, but also demonstrates the feasibility of applying those techniques in a practical setting.
Conservative parallel discrete event simulation takes a connection-oriented approach to inter-process communication. Conservative processes modeling physical entities are connected via channels that represent physical...
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ISBN:
(纸本)0769521118
Conservative parallel discrete event simulation takes a connection-oriented approach to inter-process communication. Conservative processes modeling physical entities are connected via channels that represent physical links in the target system. By contrast, optimistic strategy and its implementation in Time Warp machine, take a connectionless approach where a process can communicate freely with any other process without prior connection. This paper presents the case for a connection-oriented optimistic approach and provides a data structure for the event set of Time Warp processes that significantly reduces the cost of event scheduling and cancellation under connection-oriented operation. Detailed description of the proposed implementation is given and performance of the structure in forward event scheduling and backward event cancellation is tested and the results are discussed.
parallelsimulations using optimistic synchronization strategies such as Time Warp, operate with no regard to global synchronization since this results in greater parallelism and lower synchronization cost. However, l...
ISBN:
(纸本)0769516084
parallelsimulations using optimistic synchronization strategies such as Time Warp, operate with no regard to global synchronization since this results in greater parallelism and lower synchronization cost. However, like virtual memory, the parallel simulators may end up thrashing instead of performing useful work. The complication in using a Time Warp simulator is then to configure it suitably for good performance and avoid thrashing. Unfortunately, the optimal configuration is not generally static among different applications or even throughout an entire run of a single application. Thus, online feedback control systems are deployed to govern the adjustment of input parameters in our Time Warp simulation kernel. The design and implementation of effective feedback control systems can be difficult;the extra processing is pure overhead that must be absorbed by an), performance gains delivered. The problem is further complicated when attempting to build a simulation kernel that is designed efficiently to operate with many different applications. In this paper, we introduce a control-centric architecture that is used to monitor and manage different parts of a Time Warp simulator Specifically, we extend concepts from control theory such as adaptive control and stability, to better understand and design hierarchically-distributed run-time control systems for Time Marp based parallelsimulation.
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 it depends on the abili...
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ISBN:
(纸本)0769518532
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 it 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 by using HLA and is evaluated on three test applications.
The High-Level Architecture (HLA) provides a common architecture for distributed modeling and simulation. In its original form, the HLA allows a number of simulations to be joined together into a federation using a si...
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ISBN:
(纸本)0769518532
The High-Level Architecture (HLA) provides a common architecture for distributed modeling and simulation. In its original form, the HLA allows a number of simulations to be joined together into a federation using a single run time infrastructure. Recently there has been an interest in joining multiple such 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.
The problem of executing sequential programs in parallel using the optimistic algorithm Time Warp is considered. This is done by first mapping the sequential execution to a control tree and then assigning timestamps t...
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The problem of executing sequential programs in parallel using the optimistic algorithm Time Warp is considered. This is done by first mapping the sequential execution to a control tree and then assigning timestamps to each node in the tree. For such timestamps to be effective in either hardware or software they must be finite, this implies that they must be periodically rescaled to allow old timestamps to be reused. A number of timestamp representations are described and compared on the basis of their complexity;the frequency and cost of rescaling;and the cost of performing basic operations, including comparison and creation of new timestamps.
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