Ordering of simultaneous events in DES is an important issue as it has an impact on modelling expressiveness, model correctness as well as causal dependencies. In sequential DES this is a problem which has attracted m...
ISBN:
(纸本)9780769501550
Ordering of simultaneous events in DES is an important issue as it has an impact on modelling expressiveness, model correctness as well as causal dependencies. In sequential DES this is a problem which has attracted much attention over the years and most systems provide the user with tools to deal with such issues. This has also attracted some attention within the PDES community and we present an overview of these efforts. We have, however, not yet found a scheme which provides us with the desired functionality. Thus, we present and evaluate some simple schemes to achieve a well defined ordering of events and means to identify both causally dependent and independent events with identical timestamps in the context of optimistic simulations. These schemes should be applicable also to conservative PDES.
This paper introduces the Critical Channel Traversing (CCT) algorithm, a new scheduling algorithm for both sequential and parallel discrete event simulation. CCT is a general conservative algorithm that is aimed at th...
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ISBN:
(纸本)9780769501550
This paper introduces the Critical Channel Traversing (CCT) algorithm, a new scheduling algorithm for both sequential and parallel discrete event simulation. CCT is a general conservative algorithm that is aimed at the simulation of low-granularity network models on shared-memory multi-processor *** implementation of the CCT algorithm within a kernel called TasKit has demonstrated excellent performance for large ATM network simulations when compared to previous sequential, optimistic and conservative kernels. TasKit has achieved two to three times speedup on a single processor with respect to a splay tree central-event-list based sequential kernel. On a 16 processor (R8000) Silicon Graphics PowerChallenge, TasKit has achieved an event-rate of 1.2 million events per second and a speedup of 26 relative to the sequential kernel for a large ATM network *** is achieved through a multi-level scheduling scheme that supports the scheduling of large grains of computation even with low-granularity events. Performance is also enhanced by supporting good cache behavior and automatic load *** paper describes the algorithm and its motivation, proves its correctness and briefly presents performance results for TasKit.
This paper introduces a novel algorithm, the Active Virtual Network Management Protocol, for predictive network management. It explains how the Active Virtual Network Management Protocol facilitates the management of ...
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ISBN:
(纸本)9780769501550
This paper introduces a novel algorithm, the Active Virtual Network Management Protocol, for predictive network management. It explains how the Active Virtual Network Management Protocol facilitates the management of an active network by allowing future predicted state information within an active network to be available to network management algorithms. This is accomplished by coupling ideas from optimistic discrete event simulation with active networking. The optimistic discrete event simulation method used is a form of self-adjusting Time Warp. It is self-adjusting because the system adjusts for predictions which are inaccurate beyond a given tolerance. The concept of a streptichron and autoanaplasis are introduced as mechanisms which take advantage of the enhanced flexibility and intelligence of active packets. Finally, it is demonstrated that the Active Virtual Network Management Protocol is a feasible concept.
In this paper we present a software approach, namely Fast-Software-Checkpointing (FSC), to reduce the running time of the state saving protocol in optimistic parallel discrete event simulation. The idea behind FSC is ...
ISBN:
(纸本)9780769501550
In this paper we present a software approach, namely Fast-Software-Checkpointing (FSC), to reduce the running time of the state saving protocol in optimistic parallel discrete event simulation. The idea behind FSC is to use the instructions performed during the execution of an event as part of the state saving protocol, hence the total number of instructions due to state saving is reduced. Under FSC the time for saving the state of a logical process prior to the execution of an event e requires an amount of time proportional to the amount of state variables not updated by e's execution, as only these variables must be copied. This outlines that FSC shows some dualism with respect to incremental state saving. We show, however, that there exists a basic difference between the two solutions as in FSC some of the state saving instructions are actually event routine instructions, while in incremental state saving they are only added and mixed to the latter ones. We also present a simple software architecture to support FSC and simulation results to demonstrate the effectiveness of such solution. The obtained data show that FSC, combined with a sparse state saving strategy, may represent the best checkpointing solution in case of both medium/small state granularity simulations and large state granularity simulations even with small (but non-minimal) portions of the state updated by event execution. FSC may result therefore suited for a wide class of simulation problems.
Development of multiple robot systems which solve complex and dynamic problems in parallel and distributed manners is one of the key issues in robotics research. The multiple robot systems require robust methods to id...
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Development of multiple robot systems which solve complex and dynamic problems in parallel and distributed manners is one of the key issues in robotics research. The multiple robot systems require robust methods to identify robots for collaborative behaviors. This paper proposes a method using omnidirectional vision sensors for the identification between the robots. In addition to the several advantages of the omnidirectional vision sensor as a vision of a mobile robot, the omnidirectional vision sensor brings a significant benefit for realizing collaborative behaviors in multiple robot systems. After discussing on the algorithm, this paper shows several simulation results and real experimental results in a real environment.
The proceedings contains 22 papers from the 12th workshop on parallel and distributedsimulation. Topics discussed include: concurrency analysis and conservative methods;optimistic methods;pseudorandom number generati...
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The proceedings contains 22 papers from the 12th workshop on parallel and distributedsimulation. Topics discussed include: concurrency analysis and conservative methods;optimistic methods;pseudorandom number generation;run-time support;simulating wireless systems;and simulating communication systems.
parallel Monte Carlo simulation requires reliable RNGs. For sequential machines, good generators exist. A is not at all trivial to find high-quality RNGs for parallel machines. In this paper we present a short review ...
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ISBN:
(纸本)0818684577
parallel Monte Carlo simulation requires reliable RNGs. For sequential machines, good generators exist. A is not at all trivial to find high-quality RNGs for parallel machines. In this paper we present a short review of the main concepts to produce random numbers on parallel processors and, further, we illustrate some phenomena that occur with parallelization.
In this paper, the relationship between the computational models of Object-Oriented Rewriting and parallel Discrete-Event simulation models is explored. A discrete-event simulation program in which several objects int...
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ISBN:
(纸本)0818683325
In this paper, the relationship between the computational models of Object-Oriented Rewriting and parallel Discrete-Event simulation models is explored. A discrete-event simulation program in which several objects interact with each other by exchanging messages may have a high degree of concurrency (which can be exploited using optimistic or conservative parallelsimulation methods). We report on some observations on using Rewriting Logic in the field of parallel Discrete Event simulations, and investigate how parallelsimulation applications can be expressed using Object-Oriented Rewriting.
parallel and distributed discrete-event simulation (PDES) is a critical technology for an important class of very large complicated simulation models. However, with few exceptions, the bulk of empirical work in PDES h...
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parallel and distributed discrete-event simulation (PDES) is a critical technology for an important class of very large complicated simulation models. However, with few exceptions, the bulk of empirical work in PDES has been on small models. Furthermore, synchronization behavior is frequently complicated, which makes it very difficult to analytically prove anything about the performance executing large models on large machines. Scalability analysis asks how the performance of a certain application behaves as the application problem size increases and the parallel architecture executing it increases.
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