Data Distribution Management (DDM) is a High Level Architecture/Run-time Infrastructure (HLA/RTI) service that manages the distribution of state updates and interaction information in large scale distributed simulatio...
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ISBN:
(纸本)0769513484
Data Distribution Management (DDM) is a High Level Architecture/Run-time Infrastructure (HLA/RTI) service that manages the distribution of state updates and interaction information in large scale distributedsimulations, limits and controls the volume of data exchanged during the simulation. In this paper we focus upon the following three DDM schemes: Region-Based, Fixed and Dynamic Grid-Based techniques. In an effort to determine the most efficient model for applying the DDM service, we developed a mini-RTY Kit framework and propose a set of benchmarks to compare these DDM schemes. Using the RTI Kit, we performed extensive simulation experiments and present our analysis of the results of numerous federation executions.
Coupling multiple workstations for high performance transaction processing has become increasingly attractive for reasons of capacity, cost, and availability. PHLOX is a prototypical transaction processing system runn...
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ISBN:
(纸本)0769513840;0769513859
Coupling multiple workstations for high performance transaction processing has become increasingly attractive for reasons of capacity, cost, and availability. PHLOX is a prototypical transaction processing system running on the workstation cluster with shared disks. PHLOX supports a message oriented file system for database sharing, global cache coherency and concurrency control, affinity-based transaction routing, and sophisticated database recovery protocol. This paper describes the current prototype of PHLOX and discusses of the major design decisions that went into its construction. The lessons learned from this prototype and its predecessors are also presented.
In a distributedsimulation, simulation components of various types are executed at geographically different locations, forming a simulation federation to create a common virtual environment. Under the High Level Arch...
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In a distributedsimulation, simulation components of various types are executed at geographically different locations, forming a simulation federation to create a common virtual environment. Under the High Level Architecture (HLA), information that will be produced and consumed by a simulation component is defined in its object model, and how that information is produced and consumed is well encapsulated inside the simulation component's implementation. However, in the current implementation of the HLA's Runtime Infrastructure (RTI), information hiding between groups of simulation components in a simulation federation is not addressed. In this paper, we discuss how hierarchical federations architectures can be used to tackle this problem. The hierarchical federations architecture adopted in this paper differs from the existing architectures in that it is based on a hybrid approach for inter-operability between simulation federations. To demonstrate the information hiding using the architecture, a distributed semiconductor supply-chain simulation is also described in the paper.
We present a novel synchronisation algorithm for distributed discrete-event simulation (DDES), called the Area Virtual Time (AVT) algorithm. We first expose two orthogonal ideas of the synchronisation policy for DDES,...
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ISBN:
(纸本)0769513484
We present a novel synchronisation algorithm for distributed discrete-event simulation (DDES), called the Area Virtual Time (AVT) algorithm. We first expose two orthogonal ideas of the synchronisation policy for DDES, which is either conservative or optimistic, and the time-keeping mechanism, which is based on either Local or Global Virtual Times. The AVT algorithm is based on a network of virtual time regions, which is a happy medium between the Local Virtual Time (LVT) and the Global Virtual Time (GVT). The AVT algorithm permits the different parts of the simulation model to run either under LVT or GVT timekeeping mechanisms. This is particularly suited to models which are less than homogeneous. In those cases, mapping the models entirely to either one of the time-keeping schemes would not be efficient;or, the real-time nature of the interfaces precludes the use of GVT in those parts of the model. Our results demonstrate that the AVT algorithm progresses the simulation times faster than either the LVT or the GVT schemes, and is less sensitive to variations in some key model and communication parameters - a desirable property in distributed computation.
In this paper, a parallel Object Collection (POC) model is introduced to support data parallelism in a parallel object-oriented system. This model is based on the idea of data partitioning and method replication. To a...
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ISBN:
(纸本)0769511538
In this paper, a parallel Object Collection (POC) model is introduced to support data parallelism in a parallel object-oriented system. This model is based on the idea of data partitioning and method replication. To achieve load-balancing, partition objects are dynamically migrated at runtime according to the system load situation. A threshold-based strategy is used in the dynamic load-balancing. To avoid over-convergence of load during partition object migration, a new destination node selection algorithm is proposed. The threshold values used in the algorithm are also adaptively adjusted to better reflect the fluctuation of the load during execution. To evaluate the performance of the dynamic load balancing algorithm, simulation experiments are conducted. The simulation results are reported and discussed in the paper.
In High Level Architecture (HLA) based distributedsimulation, a federation is a set of federates, where each federate is normally executed sequentially. Our recent work on HLA-based distributed supply chain simulatio...
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The proceedings contain 14 papers. The topics discussed include: next generation real-time RTI software;hla real-time extension;a performance measurement approach for the selectively reliable multicast protocol for di...
ISBN:
(纸本)0769510531
The proceedings contain 14 papers. The topics discussed include: next generation real-time RTI software;hla real-time extension;a performance measurement approach for the selectively reliable multicast protocol for distributedsimulation;the grandest challenge in distributedsimulation;impostors-based real-time avatar behavior in virtual reality systems;adaptive attitude dead-reckoning by cumulative polynomial extrapolation of quaternions;field experience with the use of distributed interactive simulation for weapons and doctrine development;COTS middleware for real-time distributed interactive simulations - fact or fiction?;performance comparison of data distribution management strategies;aggregation/disaggregation in HLA multi-resolution distributedsimulation;and self-federating an aviation simulation using HLA: is it feasible.
This paper presents Hydra - a system designed for distributed computing on a set of heterogeneous uncommitted machines. It consists of autonomous nodes placed on participating host computers. The nodes attempt to make...
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ISBN:
(纸本)354041729X
This paper presents Hydra - a system designed for distributed computing on a set of heterogeneous uncommitted machines. It consists of autonomous nodes placed on participating host computers. The nodes attempt to make maximal use of temporarily available resources with a monitoring mechanism. Hydra nodes need no administration. Prototype was implemented in Java. Results of a sample simulation show scalability of the system.
Time Warp is known for its ability to maximize the exploitation of the parallelism inherent in a simulation. However, this potential has been undermined by the cost of processing causality violations. Minimizing this ...
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Time Warp is known for its ability to maximize the exploitation of the parallelism inherent in a simulation. However, this potential has been undermined by the cost of processing causality violations. Minimizing this cost has been one of the most challenging issues facing Time Warp. In this paper, we present dependence list cancellation, a direct cancellation technique for Time Warp which is intended for use in a distributed memory environment such as a network of workstations. This approach provides for the swift cancellation of erroneous events, thereby preventing the propagation of their (erroneous) descendants. The dependence list also provides an event filtering function which detects erroneous future events, and also reduces the number of anti-messages used in the simulation. Our experimental work indicates that dependence list cancellation results in a dramatic reduction in the time required to process causality violations in Time Warp. We focus, in this paper, on reducing the processing time required for this correction. In doing so, we make use of the inherent dependence relationship between the events in a discrete event simulation. By this we mean the parent-child relationship between events;the child event is brought into the world as a result of processing the parent event. We present algorithms for the swift cancellation of the children of erroneously processed events. These algorithms are oriented towards a distributed environment, e.g. a network of workstations. In the following, we describe the algorithms and the manner in which they serve to efficiently cancel events (sections 2 and 3) as well as experimental work intended to evaluate their efficiency (section 4). Our concluding remarks are contained in section 5.
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