• 대한기계학회논문집A
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• 제24권8호
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• pp.2131-2142
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• 2000

As recent production facilities are usually operated with unmanned material-handling system, the development of an efficient schedule with deadlock avoidance becomes a critical problem. Related researches on deadlock avoidance usually focus on real-time control of manufacturing system using deadlock avoidance policy. But little off-line optimization of deadlock-free schedule has been reported. This paper presents an optimization method for deadlock-free scheduling for Job-Shop system with no buffer. The deadlock-free schedule is acquired by the procedure that generates candidate lists of waiting operations, and applies a deadlock avoidance policy. To verify the proposed approach, simulation resultsare presented for minimizing makespan in three problem types. According to the simulation results the effect of each deadlock avoidance policy is dependent on the type of problem. When the proposed LOEM (Last Operation Exclusion Method) is employed, computing time for optimization as well as makespan is reduced.

• 대한기계학회논문집A
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• 제25권3호
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• pp.443-451
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• 2001

This paper addresses an on-line scheduling method for track systems in semiconductor fabrication. A track system is a clustered equipment performing photolithography process in semiconductor fabrication. Trends toward high automation and flexibility in the track systems accelerate the necessity of the intelligent controller that can guarantee reliability and optimize productivity of the track systems. This paper proposes an-efficient on-line scheduling method that can avoid deadlock inherent to track systems and optimize the productivity. We employ two procedures for the on-line scheduling. First, we define potential deadlock set to apply deadlock avoidance policy efficiently. After introducing the potential deadlock set, we propose a deadlock avoidance policy using an on-line Gantt chart, which can generate optimal near-optimal schedule without deadlock. The proposed on-line scheduling method is shown to be efficient in handling deadlock inherent to the track systems through simulation.

• 산업경영시스템학회지
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• 제23권58호
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• pp.49-58
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• 2000

In order to resolve a deadlock problem in manufacturing systems, three main methods have been proposed-prevention, avoidance, and recovery. The prevention and avoidance methods require predicting deadlocks in advance in order to prohibit them. In contrast, the recovery method allows a system to enter a deadlock state, then resolves it usually using a common buffer. In this paper, a deadlock recovery method considering the impact of flexible job routings is proposed. This method is based on capacity-designated directed graph (CDG) model representing current requesting and occupying relations between Jobs and resources in order to detect a deadlock and then recovers it.

• 공학논문집
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• 제1권1호
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• pp.49-57
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• 1997

본 논문에서는 Habermann의 deadlock 회피책에 대한 기존의 방안을 향상시킬 수 있는 방법을 고안하였다. 먼저 correction, efficiency, concurrency 측면에서 기존의 개선 방법들을 비교 분석한 다음, 대표적인 Kameda의 개선방안을 심도있게 논의한다. Dinic의 알고리듬을 채택한 Kamedia의 방법에서는 실행시간 O($mn^1.5$)이 요구되지만 Karzanov의 wave method를 응용하여 본고에서 제안한 faster algorithm에서는 실행시간 O($mn^1.5$)이 됨을 보인다.

• International Journal of Computer Science & Network Security
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• 제22권10호
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• pp.230-236
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• 2022

Objectives: The primary goal of this article is to compare the multiple algorithms used for deadlock handling methods and then outline the common method in deadlock handling methods. Methods: The article methodology begins with introducing a literature review studying different algorithms used in deadlock detection and many algorithms for deadlocks prevented, recovered, and avoided. Discussion and analysis of the literature review were done to classify and compare the studied algorithms. Findings: The results showed that the deadlock detection method solves the deadlock. As soon as the real-time deadlock detection algorithm is identified and indicated, it performs better than the non-real-time deadlock detection algorithm. Our novelty the statistics that we get from the percentages of reviewing outcomes that show the most effective rate of 47% is in deadlock prevention. Then deadlock detection and recovery with 28% finally, a rate of 25% for deadlock avoidance.

• 한국시뮬레이션학회논문지
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• 제15권1호
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• pp.1-10
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• 2006

유연생산시스템은 많은 병렬적이고 동시 발생적인 기계들, 장치들, 수송 시스템들로 구성되며, 이러한 것들은 각각 버퍼들, 도구들, 라우터들로 나누어진다. 시스템에서 여러 생산품들의 병렬적인 흐름은 자원들을 이용하기 위해 서로 경쟁하게 되며, 유연생산시스템의 이러한 특징들로 인해 교착상태가 발생한다. 교착상태는 상대방이 점유하고 있는 자원을 서로 요구하는 과정에서 흐름이 멈추어진 상태를 말하므로, 이러한 교착상태의 탐지와 회피는 매우 중요한 문제이다. 이 사실에 근거하여 일반 플레이스와 자원공유플레이스 사이의 관계를 나타내는 DAPN(Deadlock Avoidance Petri Wet)을 정의하여 교착상태를 탐지하고 회피하기 위한 새로운 알고리즘을 연구하였다. 또한 제안된 알고리즘을 유연생산시스템의 특징을 가진 모델에 적용하여 그 결과를 제시한다.

• 제어로봇시스템학회논문지
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• 제11권4호
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• pp.344-352
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• 2005

The modem production systems are required to produce many items. This is due to the fact that society has become more complex and the customers' demands have become more varied. The demand for complex production systems of various purposes, which can flexibly change the content of work, has increased. One of such production systems is FMS (Flexible Manufacturing System). Limited resources must be used in FMS when a number of working procedures are simultaneously being undertaken because the conditions of stand-by job processes cannot be changed. Researchers are currently being conducted to determine ways of preventing deadlocks. In this study, we proposes the algorithm for detection and recovery of a deadlock status using the DDAPN(Deadlock Detection Avoidance Petri Net). Also, we apply the proposed algorithm has a feature to the FMS.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권8호
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• pp.585-593
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• 2004

Fault-tolerant gait planning in legged locomotion is to design gaits with which legged robots can maintain static stability and motion continuity against a failure in a leg. For planning a robust and deadlock-free fault-tolerant gait, kinematic constraints caused by a failed leg should be closely examined with respect to remaining mobility of the leg. In this paper, based on the authors's previous results, deadlock avoidance scheme for fault-tolerant gait planning is proposed for a hexapod robot walking over even terrain. The considered fault is a locked joint failure, which prevents a joint of a leg from moving and makes it locked in a known position. It is shown that for guaranteeing the existence of the previously proposed fault-tolerant tripod gait of a hexapod robot, the configuration of the failed leg must be within a range of kinematic constraints. Then, for coping with failure situations where the existence condition is not satisfied, the previous fault-tolerant tripod gait is improved by including the adjustment of the foot trajectory. The foot trajectory adjustment procedure is analytically derived to show that it can help the fault-tolerant gait avoid deadlock resulting from the kinematic constraint and does not make any harmful effect on gait mobility. The post-failure walking problem of a hexapod robot with the normal tripod gait is addressed as a case study to show the effectiveness of the proposed scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 D
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• pp.2298-2300
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• 2003

본 논문은 페트리 네트의 특별한 구조인 siphon의 특성을 이용하여 트랜지션 점화를 제어함으로써 deadlock을 회피하는 방법을 제시한다. 제안한 방법은 페트리 네트에서 상태 방정식을 유도한 후, siphon의 특성을 이용하여 deadlock을 회피할 수 있는 충분 조건을 유도한다. 간단한 FMS의 예를 이용하여 제안한 방법을 사용하면 deadlock이 발생하지 않음을 보인다.

• 대한산업공학회지
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• 제26권4호
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• pp.392-401
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• 2000

In this work, a deadlock avoidance strategy is proposed in order to effectively handle conflicts and deadlocks occurring in zone-control AGV (Automated Guided Vehicle) systems. The basic idea is based on Capacity-designated Directed Graph (CDG) theory that was developed to avoid from deadlocks in manufacturing systems. However, to enforce the effectiveness of detecting impending and restricted deadlocks, AGV routings are explicitly described in Extended Directed Graph (EDG). From EDG, a non-conservative deadlock-avoidance strategy is derived. The superiority of the proposed strategy lies on the applicability to diverse AGV path configurations using zone control. Also, because of its insensibility and robustness, it can be effectively used when the system has randomness and stochastic nature.