• KIPS Transactions on Computer and Communication Systems
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• v.4 no.3
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• pp.85-90
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• 2015

In this paper, anew parallel event-driven logic simulation is proposed. As the proposed prediction-based parallel event-driven simulation method uses both prediction data and actual data for the input and output values of local simulations executed in parallel, the synchronization overhead and the communication overhead, the major bottleneck of the performance improvement, are greatly reduced. Through the experimentation with multiple designs, we have observed the effectiveness of the proposed approach.

• KIPS Transactions on Computer and Communication Systems
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• v.8 no.3
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• pp.57-64
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• 2019

In this paper, an efficient prediction-based parallel simulation method using spatially partial simulation strategy is proposed for improving both the performance of the event-driven gate-level timing simulation and the debugging efficiency. The proposed method quickly generates the prediction data on-the-fly, but still accurately for the input values and output values of parallel event-driven local simulations by applying the strategy to the simulation at the higher abstraction level. For those six designs which had used for the performance evaluation of the proposed strategy, our method had shown about 3.7x improvement over the most general sequential event-driven gate-level timing simulation, 9.7x improvement over the commercial multi-core based parallel event-driven gate-level timing simulation, and 2.7x improvement over the best of previous prediction-based parallel simulation results, on average.

• KIPS Transactions on Computer and Communication Systems
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• v.4 no.5
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• pp.147-152
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• 2015

In general, there are two synchronization methods in parallel event-driven simulation, pessimistic approach and optimistic approach. In this paper, we propose a new approach, sporadic synchronization combining both for prediction-based parallel event-driven logic simulation. We claim this hybrid solution is pretty effective to minimize both checkpoint overhead and restart overhead, which are related problems with frequent false predictions for improving the performance of the prediction-based parallel event-driven logic simulation. The experiment has clearly shown the advantage of the proposed approach.

• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.1-9
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• 2010

This paper describes parallel event-driven remote IT convergence applications which are a combination of traditional industry and IT Technology including advanced communication. In IT convergence system, events can occur currently from many sensors of devices or users. And IT convergence system must have a parallel processing method. In this paper, the parallel processing method was implemented using a thread and we developed a connection method between a device and a mode of communication which is a wireless communication or a power line communication. In addition to that, we developed object modeling, device, user and event modeling, based on XML (eXtensible Markup Language) using object-oriented modeling method. To efficiently show results in real time, systems provide various graphic user interfaces such as a bar graph, a table, and a combination of the two.

• KIPS Transactions on Computer and Communication Systems
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• v.5 no.12
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• pp.439-446
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• 2016

In this paper, an efficient prediction accuracy enhancement strategy is proposed for improving the performance of the prediction-based parallel event-driven gate-level timing simulation. The proposed new strategy adopts the static double prediction and the dynamic prediction for input and output values of local simulations. The double prediction utilizes another static prediction data for the secondary prediction once the first prediction fails, and the dynamic prediction tries to use the on-going simulation result accumulated dynamically during the actual parallel simulation execution as prediction data. Therefore, the communication overhead and synchronization overhead, which are the main bottleneck of parallel simulation, are maximally reduced. Throughout the proposed two prediction enhancement techniques, we have observed about 5x simulation performance improvement over the commercial parallel multi-core simulation for six test designs.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10c
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• pp.628-630
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• 2003

이벤트 알림 시스템에 대한 연구는 비동기적으로 발생되는 이벤트를 기반으로 실행되는 응용 프로그램을 지원하기 위하여 많은 연구가 이루어져 왔다. 본 논문은 확장성과 효율성을 보장하기 위한 Push 기반 이벤트 알림 서비스를 제시한다. 특히 이벤트 중재자(Broker)를 확장하기 쉽게 구현 하였으며, 병렬적 데이터 전송 등을 통하여 데이터 전송 효율성을 제공해 주고 있다. 또한 XML을 사용한 레코드 기반 이벤트 모델을 구현하여 이기종 호환성 보장과 구현 언어 독립적인 구조를 제공하고 있다. 구현된 이벤트 알림 서비스에 대해 구현 이슈를 살펴보고, 성능 측정하고 그 결과를 분석한다.

• Journal of KIISE:Software and Applications
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• v.27 no.2
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• pp.108-119
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• 2000

Most of prior works on testing parallel programs have concentrated on how to guarantee the reproducibility by employing event traces exercised during executions of a program. Consequently, little work has been done to generate meaningful event sequences, especially, from specifications. This paper describes techniques for deriving event sequences from Message Sequence Charts(MSCs) which are widely used in telecommunication areas for its simplicity in specifying the behaviors of a program. For deriving event sequences from MSCs, we have to uncover the causality relations among events embedded implicitly in MSCs. In order to attain this goal, we adapt vector time stamping which has been previously used to determine the ordering of events taken place during an execution of interacting processes. Then, valid event sequences, satisfying the causality relations, are generated according to the interleaving rules suggested in this paper. The feasibility of our testing technique was investigated using the phone conversation example. In addition, we discussed on the experimental results gained from the example and how to combine various test criteria into our testing environment.

• The KIPS Transactions:PartA
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• v.10A no.2
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• pp.111-122
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• 2003

Military wargame simulation models must support the HLA in order to facilitate interoperability with other simulations, and using parallel simulation engines offer efficiency in reducing system overhead generated by propelling interoperability. However, legacy military simulation model engines process events using sequential event-driven method. This is due to problems generated by parallel processing such as synchronous reference to global data domains. Additionally. using legacy simulation platforms result in insufficient utilization of multiple CPUs even if a multiple CPU system is under use. Therefore, in this paper, we propose conversing the simulation engine to an object model-based parallel simulation engine to ensure military wargame model's improved system processing capability, synchronous reference to global data domains, external simulation time processing, and the sequence of parallel-processed events during a crash recovery. The converted parallel simulation engine is designed and implemented to enable parallel execution on a multiple CPU system (SMP).

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.618-620
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• 2000

최근 네트워크를 이용한 분산환경에서의 작업이 늘고 있다. 이러한 네트워크 환경에서의 병렬프로그램은 그 수행 과정이 일반 순차 프로그램보다 복잡해서 프로그램 진행과정을 파악하기가 어렵다. 그래서 병렬프로그램을 쉽게 분석할 수 있도록 성능감시기에 대한 연구가 진행되고 있다. 이에 본 논문에서는 JaNeC 환경에서 동작하는 병렬프로그램의 진행과정을 이벤트가 발생하는 동안에 실시간으로 볼 수 있도록 온라인 성능감시기에 대해서 설명한다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.460-462
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• 2003

본 연구에서는 리눅스 클러스터에서 효과적으로 병렬 MPI 프로그램을 실행시키기 위해, 메시지 전달 이벤트를 토대로 통신에 창설하는 프로세스들이 동시에 스케줄링되는 기법을 설계 구현하였다. 실제 병렬프로그램의 실행을 통해 측정한 결과에 따르면, 통신량이 높은 프로그램에서 33-56%의 실행 시간 감소효과를 보였다.