• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.476-481
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• 1991

This paper investigates the relationship between the two problems, supervisor reduction and observation function (projection) design, which arise in supervisory control of DEDS. It is shown through an example that a reduced supervisor of minimal size does not necessarily result in a maximal projection when a projection design method which uses the transition structure of a supervisor is applied. Also, if an L-realizable projection P is available and if a supervisor has a special structural feature, a cover C for supervisor reduction can be easily obtained. By investigating the control-compatibility of states of the reduced supervisor based on C, we can also check maximality of P in a simple manner.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.318-323
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• 1993

The paper discusses the problem of computing coarser observation functions in supervisory control of discrete event systems. It is shown that when a supervisor that realizes a given language L has certain properties, L-realizability of a coarser observation function is equivalent to control-compatibility of the states in some subsets of the state space of the supervisor. This characterization is then used to devise an iterative procedure of computing coarser L-realizable observation functions, where supervisor reduction and L-realizability verification of an observation function are performed at each iteration.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.73.5-73
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• 2001

In this paper, we present a procedure to design the robust optimal supervisor which has the minimal cost in the sense of average for a given multiple-modelled discrete event system DES. In order to design the robust optimal supervisor, we extend the optimal supervisor design algorithm for a deterministic DES to the case of multiple-modelled DESs. In addition, using the proposed algorithm with modified costs of events and penalities of states, we can show whether a robust supervisor for a given multiple-modelled DES exists and design the minimally restricted robust supervisor.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.43-55
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• 2018

The biggest change in the field of coastal ship safety control since the accident of passenger ship Sewol has been the introduction of the maritime safety supervisor system. With its introduction, the safety control system in coastal passenger ships was changed from consisting of operation managers and marine police to operation managers and a newly-introduced maritime safety supervisor. The safety control system for coastal cargo ships was also converted from relying on ship inspection officers to having a maritime safety supervisor and ship inspection officers. However some negative elements have surfaced due to confusion related to the scope of work in the coastal cargo shipping field. These have been caused by dividing the supervisory agency, a lack of work continuity given non-permanent public official status, low supervisor qualifications overlooking reality, and limitations of the order for improvement to secure seaworthiness. It is essential that the maritime safety supervisor system be solidified to reinforce coastal ship safety control. Therefore, systematic safety control in the coastal cargo shipping industry should be conducted by a single, integrated government agency, and the area covered by the order for improvement to secure seaworthiness should be extended. Also limitations of the supervisor recruitment system due to non-permanent public official status should be simultaneously improved. In addition, it is necessary to upgrade supervisor qualifications to require experience with surveyors of international class, ship captains, and chief engineers.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.6-7
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• 2017

• Annual Conference of KIPS
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• 2007.05a
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• pp.785-788
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• 2007

본 연구는 Ramadege 와 Wonham 의 Supervisor Control 을 기반으로 한다. 초기 이 이론은 오토마타를 이용하여 모델링 하였으며, 많은 연구가 활발하게 이루어져왔다. 그러나, 유한 오토마타는 병렬처리 및 동기화, 자원공유를 모델링하기 어렵다는 단점이 있다. 유한 오토마타를 기반으로 한 연구는 일반적으로 복잡한 시스템을 모델링 할 때 발생하는 결합 폭발성에 의한 제한성이 있다. 반면, 패트리 넷은 병렬처리나 동기화에 대한 모델링을 하기에 보다 더 강력한 도구이지만, 패트리 넷을 이용한 통합법은 아직까지 광범위하게 연구되지는 않았다. 따라서, 본 연구에서는 공장설비(plant)모델과 이 설비에 대해 사용자가 원하는 작업을 명시한 사용자 설계명세 (user specifications)모델을 패트리 넷을 이용하여 모델링하는 방법을 제안한다. 본 연구는 사용자 설계명세에 관련한 폐쇄 회로 패트리 넷(closed-loop PN)을 획득하고자 원시 공장설비 모델에 제어 플래이스(control place)를 추가하는 통합을 실행하기 위한 방법으로 Ghaffari의 영역 이론(Theory of Region )을 이용하여 연구개발 하였다

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.10a
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• pp.182-182
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• 2003

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.6
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• pp.478-485
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• 2000

A discrete event systems (DES) is a physical system that is discrete in time and state space, asynchronous (event rather than clock-driven), and in some sense generative(or nondeterministic). This paper presents the design of fifteen modular supervisors to control an experimental CIM testbed. These supervisors are nonblocking, controllable and nonconflicting. After verification of the supervisors by simulation, the supervisors for AGV system have been implemented to demonstrate their efficacy.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.411-413
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• 1997

This paper presents the problem of fault-tolerant robust supervisory control of timed discrete event systems (DESs). First the concept of faults is quantitatively defined in timed DESs and fault tolerable event sequences are presented as a desired legal language. Given a timed DES with model uncertainty, the conditions for the existence of a supervisor which always guarantees fault tolerable event sequences embedded in the system are derived.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.104.4-104
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• 2001

This paper addresses a supervisory control problem to meet bounded time constraints in real-time nondeterministic discrete event systems (DESs) represented as timed transition models. For a timed language specification representing a bounded time constraint, this paper introduces the notions of trace-controllability and time-controllability. Based on the notions, this paper presents the necessary and sufficient conditions for the existence of a supervisor for a real-time nondeterministic DES to achieve the specification.