• 대한전자공학회논문지TC
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• 제40권1호
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• pp.8-14
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• 2003

본 논문에서는 그룹키를 이용하는 보안 멀티캐스트 환경에서 그룹키 노출로 인한 정보손실과 그룹키 재분배의 과정에 대하여 연관지어 설명한다. 또한 손실된 정보에 대한 비용과 키 갱신에 소요되는 비용의 과제를 결합하여 최소의 비용을 갖는 최적의 rekey interval을 분석한다. 본 분석의 결과를 이용하면 그룹키 재분배에 있어서 비용적인 면을 효율성의 척도로 하여, 회원수, 회원의 보안 능력 및 탈퇴율등을 반영하여 rekey interval을 구함으로서 최소비용으로 그룹을 관리할 수 있다. 이러한 효율적인 rekey interval 할당에 대한 연구는 지금까지 크게 중요시되지 않던 부분이었으나 rekey interval 할당에 대한 문제를 현재보다 개선하고 보완한다면, 보안 멀티캐스트 그룹의 활강성과 활용성을 증가시킬 수 있을 것이다.

• 산업경영시스템학회지
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• 제5권7호
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• pp.9-15
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• 1982

The rectilinear-distance location problem combines the property of being a very appropriate distance measure for a large number of location problems and the property of being very simple to treat analytically. An obvious question to be asked at the optimal point which is obtained by the rectilinear distance method is, "what if the point is not available as a location site\ulcorner." The point may, for example, be inaccessible or may coincide with the location of another structure, a river, or a municipal park. In this case, one approach that may be employed is to construct contour lines (also called iso-cost or level curves) of the cost function. Contour lines provide considerable insight into the shape of the surface of the total cost function as well as a useful means of evaluating alternative locations for the new facility. But, when there is an obstacle which divides the application area into two. The optimal location(which is acquired by the rectilinear distance method) is not coincide with the minimal cost point and the contour line is occasionally of no use, this paper shows the method of finding a way to decide an optimal point of single facility location in this case.this case.

• Communications for Statistical Applications and Methods
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• 제17권6호
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• pp.865-877
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• 2010

본 논문에서는 보증기간이 종료된 이후의 수리가 가능한 시스템에 대한 주기적인 예방보전모형을 고려하는데, 무료수리보증, 비례수리보증 그리고 혼합수리보증과 같은 세 종류의 수리보증정책을 고려한다. 이러한 세 종류의 수리보증기간이 종료된 이후의 수리가 가능한 시스템에 대한 주기적인 예방보전모형에 대하여 각각 기대순환길이, 총기대비용 그리고 단위시간당 기대비용을 유도한다. 또한 유도된 단위시간당 기대 비용을 최소화하는 최적의 예방보전정책인 최적의 예방보전주기와 예방보전횟수를 결정하는 방법에 대하여 설명한다. 끝으로 고장시간이 와이블분포를 하는 경우에 최적의 주기적 예방보전정책을 결정하여 본다.

• 대한산업공학회지
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• 제8권2호
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• pp.33-36
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• 1982

This paper considers preventive maintenance policies for a system with two types of units which is subject to deterioration. Two generalized models are investigated ; a preventive maintenance policy based on the cumulative operating time and a policy based on the number of minimal repairs performed. Optimal preventive maintenance policies which minimize the expected average cost per unit time including the earning loss due to the deterioration are discussed and some numerical examples are given.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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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.

• 산업경영시스템학회지
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• 제17권32호
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• pp.221-226
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• 1994

Almost preventive maintenance policies assumed that the system after pm has failure rate as before pm with probability p and as good as new with probability 1-p. This paper considers the s-expected cost of the model with imperfect periodic preventive maintenance that increasing minimal repair costs at failure and obtains the optimum periodic preventive maintenance time. Numerical example are shown in which the failure time of the system has gamma distribution.

• 산업경영시스템학회지
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• 제24권67호
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• pp.19-26
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• 2001

A design issue for a flexible manufacturing system is to find the number of each resource type which assures a given production ratio with a minimal cost. The FMS is modeled as a closed queueing network with a local buffer of limited capacity. An efficient method to determine this optical configuration is presented. The proposed method consists of three steps : 1) determine a lower configuration, 2) derive a heuristic solution, 3) find the optimal solution. The derived heuristic solutions are close to the optical solution.

• 대한전기학회논문지
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• 제33권2호
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• pp.47-55
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• 1984

This paper is concerned with a computer-aided state assignment, that is, coding race-free internal states of asynchronous sequential circuits, and a method for minimizing the combinational network of asynchronous sequential circuits. The FORTRAN version of the peoposed algorithm results in race-free state assignments and reduction of the number of connections and gates with near minimal hardware cost. Some examples are designed by the proposed computer program to illustrate the algorithm in this paper. Finally, results are compared with those of the other methods.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2010년도 춘계학술발표논문집 1부
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• pp.436-439
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• 2010

본 논문에서는 Ubiquitous Computing 환경 하에서 이종 시스템 간의 통합을 위한 데이터 관리 기법 모델을 제안하였다. 이종 시스템 간의 통합이 이루어지면 방대한 양의 데이터를 모든 시스템이 공유해야 하기 때문에 무분별한 데이터의 중복과 저장으로 인해 프로세스의 데이터 처리 성능 및 데이터 무결성을 보장받지 못 하는 등의 문제점이 발생한다. 이를 보완하기 위해 Minimal cost Spanning tree의 원리를 적용하여 시스템 통합에 따른 데이터 처리 및 무결성 문제 해결을 위한 메커니즘을 제시하고자 한다.

• 한국군사과학기술학회지
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• 제4권1호
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• pp.170-176
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• 2001

An optimization problem to obtain the optimal replacement interval considering the salvage values is studied. The system is minimally repaired at failure and is replaced by new one at age T(periodic replacement policy with minimal repair of Barlow and Hunter〔2〕). Our model assumes that the time horizon associated with the number of replacements is random The total expected cost considering the salvage values with random time horizon is obtained and the optimal replacement interval minimizing the cost is found by numerical methods. Comparisons between non-considered salvage values and this case are made by a numerical example.