• Journal of the Korea Society of Computer and Information
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• v.8 no.3
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• pp.26-33
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• 2003

The edge-chasing deadlock detection algorithm of Choudhary fails to remove the existing deadlocks after committing the transaction whose priority is lowest on the transaction wait-for path. We proposed a modified algorithm that solves this problem. In this thesis, the performance of the modified algorithm is compared with that of the Tsai's deadlock detection algorithm that uses transaction-resource graph(TR graph) using simulation approach.

• Proceedings of the Korea Information Processing Society Conference
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• 2007.05a
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• pp.751-754
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• 2007

본 연구에서는 유연생산시스템에서의 교착상태 확인 및 회피 알고리즘을 추이적 행렬을 이용하여 제안한다. 추이적행렬은 플레이스와 플레이스간의 관계를 표현함으로 마킹의 흐름을 플레이스와 트랜지션간의 관계형에서 상태와 상태간의 관계를 표현함으로 상태의 변화 검증에 편리하다. 교착상태 확인 및 회피 알고리즘을 제시하고, 기존에 발표되어진 siphon과 DAPN알고리즘간의 비료 검토를 통하여 제안한 알고리즘의 유용성을 검증하였다.

• Journal of the Korea Society for Simulation
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• v.18 no.1
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• pp.9-16
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• 2009

Since a deadlock is a condition in which the excessive demand for the resources being used by others causes activities to stop, it is very important to detect and prevent a deadlock. About the deadlock detection analysis methods are may divide like as Siphon, DAPN and transitive matrix, but it's very difficult to evaluate the performance. Since DES (Discrete Event Systems) is NP-hard, and these detection and avoidance methods used various factors in each technique, it's made difficult to compare with each other's. In this paper, we are benchmarked these deadlock detection analyze methods based on the complexity, the detection time and the understanding after approached to one example.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.2
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• pp.49-54
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• 2005

This Paper Presents a non-blocking deadlock detection scheme with immediate cycle detection in multiprocessing systems. We assume an expedient state and a special case where each type of resource has one unit and each request is limited to one resource unit at a time. Unlike the previous deadlock detection schemes, this new method takes O(1) time for detecting a cycle and O(n+m) time for blocking or handling resource release where n and m are the number of processes and that of resources in the system. The deadlock detection latency is thus minimized and is constant regardless of n and m. However, in a multiprocessing system, the operating system can handle the blocking or release on-the-fly running on a separate processor, thus not interfering with user process execution. To some applications where deadlock is concerned, a predictable and zero-latency deadlock detection scheme could be very useful.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04a
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• pp.694-696
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• 2002

본 연구에서는 패트리 넷에서의 교착 상태 확인을 추이적 행렬을 이용하여 분석하는 기법을 제안한다. 교착 상태란 패트리 넷에서 마킹이 더 이상 진행 되지 못하고 서로 점화 가능 상태를 기다리는 상태로 자원 공유의 문제에서 많이 발생 가능하다. 따라서. 모든 플레이스와 트랜지션과의 관계를 나타내는 추이적 행렬을 이용하여 간단하게 확인분석이 용이한 기법을 제안한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.73-78
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• 2023

The dining philosophers problem(DPP) is that five philosophers sit around a round table and eat spaghetti(or noodles) together, where they must have a pair of chopsticks(two) on both sides of them to eat, and if all philosophers have one chopstick on the right, no one can eat because the deadlock occurs. Deadlocks are a problem that frequently occur in parallel systems, and most current operating systems(OS) cannot prevent it. This paper proposes a silver bullet that causes no deadlock in an OS where all processors of 2≤n≤∞ have multiple parallel processing capabilities. The proposed method is a group round-robin method in which ⌊n/2⌋ odd processors form a group and perform simultaneously, and shift right to the next processor when execution ends. The proposed method is to perform two times for even processors, three times for odd processors per one round-robin. If the proposed method is performed n times, even-numbered processors perform n/2 times and odd-numbered processors perform (n-1)/2-times.

• Journal of Internet Computing and Services
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• v.7 no.6
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• pp.79-86
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• 2006

Many of concurrency control for client-sewer database systems have been proposed and studied in the literature. However, commonly known schemes do not manage to the case of dramatic changes in data contention because the data contention of database systems is changed for each cases. In this paper, we propose o hybrid concurrency control. The proposed scheme uses a optimistic scheme for the first-run transactions and a pessimistic scheme for the second-run transactions. By pre-claiming locks in the second phase, deadlocks which ore possible in pessimistic based concurrency control are prevented in our approach. In addition, the scheme ensures at most one re-execution even if the validation in the optimistic phase fails. By a detailed simulation, this paper examines the behaviors of the Distributed Optimistic Concurrency Control and the proposed scheme. The simulation study shows our scheme outperforms Distributed Optimistic Concurrency Control in our experimental result.

• Nuclear industry
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• v.38 no.5
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• pp.21-26
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• 2018

고준위 방사성폐기물 처분사업은 미 의회 내에서도 골치 아프고 민감한 문제로서 지난 몇 년간 아무 해결책 없이 손을 놓고 있는 상태이다. 교착 상태에 빠져 있는 이 문제는 올해 치러지는 선거가 끝난 후에나 해결책이 나올 수 있을 것으로 전망되고 있다.

• Proceedings of the Korea Society for Simulation Conference
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• 1996.05a
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• pp.10-14
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• 1996

본 논문은 토러스 망의 패킷 전송 효율을 평가하기 위해 각 노드가 에지당 2개의 입·출력 큐를 가지는 라우팅 알고리즘을 제시하고 시뮬레이션을 수행하여 그 결과를 분석하였다. 제시된 4가지 오름순차를 가지는 라우팅 알고리즘에 대해 시뮬레이션을 하기 위해 도착분포와 서비스분포는 지수분포를 갖도록하여 교착상태가 없는 패킷 전송 효율을 비교 평가하였다. 실험 결과로부터 무교착 상태로 패킷을 전달하기 위한 노드 큐의 크기를 알 수 있었고, 또한 입력 패킷 메시지의 분포에 따라 패킷의 전송 효율을 높이기 위한 버퍼의 크기를 예측할 수 있었다.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.11 no.1
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• pp.37-46
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• 1993