• 한국지능시스템학회논문지
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• 제14권5호
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• pp.563-570
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• 2004

Genetic algorithms have been successfully applied to various optimization problems belonging to NP-hard problems. The sequential ordering problems(SOP) and the job shop scheduling problems(JSP) are well-known NP-hard problems with strong influence on industrial applications. Both problems share some common properties in that they have some imposed precedence constraints. When genetic algorithms are applied to this kind of problems, it is desirable for genetic operators to be designed to produce chromosomes satisfying the imposed precedence constraints. Several genetic operators applicable to such problems have been proposed. We call such genetic operators precedence-preserving genetic operators. This paper presents three existing precedence-preserving genetic operators: Precedence -Preserving Crossover(PPX), Precedence-preserving Order-based Crossover (POX), and Maximum Partial Order! Arbitrary Insertion (MPO/AI). In addition, it proposes two new operators named Precedence-Preserving Edge Recombination (PPER) and Multiple Selection Precedence-preserving Order-based Crossover (MSPOX) applicable to such problems. It compares the performance of these genetic operators for SOP and JSP in the perspective of their solution quality and execution time.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.305-308
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• 2007

In this paper we suggest an efficient evolutionary approach based on topological sort techniques for precedence constrained TSPs. The determination of optimal sequence has much to offer to downstream project management and opens up new opportunities for supply chains and logistics. Experimental results show that the suggested approach is a good alternative to locate optimal solution for complicated precedence constrained sequencing as in optimization method for instance.

• 한국경영과학회지
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• 제23권4호
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• pp.1-10
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• 1998

We consider the precedence-constrained knapsack problem. which is a knapsack problem with precedence constraints imposed on the set of variables. Especially, we focus on the case where the precedence constraints cir be represented as a bipartite graph, which occurs most frequently in applications. Based on the previous studios for the general case, we specialize the polyhedral results on the related polytope and derive stronger results on the facet-defining properties of the inequalities.

• 한국통계학회:학술대회논문집
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• 한국통계학회 2005년도 춘계 학술발표회 논문집
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• pp.197-201
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• 2005

In this article, we will compare the performance of the mean control chart, the median control chart, the transformed mean control chart, the transformed median control chart, and the precedence control chart by simulation study. For control charts with transformed data, Yeo-Johnson transformation is used. Under the in-control condition, ARL's in all control charts coincide with the designed ARL in the normal distribution, but in the other distributions, only the precedence control chart provides the in-control ARL as designed. Under the out-of-control condition, the mean control chart is preferred in the normal distribution and the median control chart is preferred in the heavy-tailed distribution and the precedence control chart outperforms in the short-tailed distribution.

• 한국산학기술학회논문지
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• 제9권5호
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• pp.1392-1398
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• 2008

본 논문에서는 분해우선작업을 가지는 페트리 넷 기반의 분해순서계획모델을 제안한다. 모든 가능한 분해순서는 분해트리에 의해 생성되고, 분해우선순위와 분해가치 행렬을 이용하여 분해순서를 결정한다. 분해작업의 우선순위는 분해트리를 통하여 결정하고 분해작업의 가치는 제품의 마지막 수명단계의 경제적 분석에 의해 유도된다. 분해우선작업을 가지는 분해계획모델을 해결하기 위하여, 본 연구에서는 페트리 넷 기반의 휴리스틱 알고리듬을 개발한다. 개발된 알고리듬은 페트리 넷 모델의 전이순서에 기반을 두어 도달할 수 있는 모든 그래프의 노드를 탐색하여 최적의 혹은 근사최적의 분해순서를 생성한다. 본 연구에서는 냉장고를 대상으로 제안모델의 유효성을 입증한다.

• 응용통계연구
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• 제29권1호
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• pp.243-255
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• 2016

경기종합지수가 개발되고 시간이 흐르다보면 경제현상 자체의 패턴 변화나 구성 지표의 경기대응력 변화 등으로 경기를 정확하게 판단하고 예측하는데 한계가 발생하기도 한다. 미래의 경기를 비교적 정확하게 예측하기 위해서는 먼저 선행성이 높은 개별지표를 선택해야 한다. 본 연구에서는 제주지역 경기선행지수 구성지표인 건축허가면적, 소비자물가지수, 서비스업생산지수, 광공업생산지수, 서귀포평균기온, 신용카드 구매액에 대한 경기전환점 및 시차상관분석을 통하여 구성지표 선행여부 타당성에 대한 실증분석을 하고자 한다. 또한 적정한 제주지역 선행종합지수의 기준 순환일을 설정하여 제안하고 전국 경기선행지수와의 비교분석을 통하여 제주지역 선행지수 구성 지표를 검증하고자 한다. 이를 통하여 제주지역 경기종합지수가 가지고 있는 문제점 및 향후 지역 종합경기지수의 개선 방향을 제안하고자 한다.

• 대한산업공학회지
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• 제3권2호
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• pp.93-97
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• 1977

PERT/CPM type scheduling systems use a network to graphically portray the interrelationship among the activities of a project. This network representation of the project schedule shows all the precedence relationship regarding the order in which tasks must be performed. In this paper an algorithm is presented that changes the network configurations without violating precedence relationship of the original network.

• International Journal of Contents
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• 제10권4호
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• pp.30-37
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• 2014

The current study was conducted to examine the temporal and spatial activation sequences related to morphosyntactic, semantic and orthographic-lexical sentences, focusing on the morphological-orthographic and lexical-semantic deviation processes in Korean language processing. The Event-related Potentials (ERPs) of 15 healthy students were adopted to explore the processing of head-final critical words in a sentential plausibility task. Specifically, it was examined whether the ERP-pattern to orthographic-lexical violation might show linear precedence over other processes, or the presence of additivity across combined processing components. For the morphosyntactic violation, fronto-central LAN followed by P600 was found, while semantic violation elicited N400, as expected. Activation of P600 was distributed in the left frontal and central sites, while N400 appeared even in frontal sites other than the centro-parietal areas. Most importantly, the orthographic-lexical violation process revealed by earlier N2 with fronto-central activity was shown to be complexes of morphological and semantic functions from the same critical word. The present study suggests that there is a linear precedence over the morphological deviation and its lexical semantic processing based on the immediate possibility of lexical information, followed by sentential semantics. Finally, late syntactic integration processes were completed, showing different topographic activation in order of importance of ongoing sentential information.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.747-752
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• 2004

Researches about scheduling of the distributed real-time systems have been proposed. However, they have some weak points, not scheduling both sporadic and periodic tasks and messages or being unable to guaranteeing the end-to-end constraints due to omitting precedence relations between sporadic tasks. So this paper proposes a new scheduling method for distributed real-time systems consisting of sporadic and periodic tasks with precedence relations and sporadic and periodic messages, guaranteeing end-to-end constraints. The proposed method is based on a binary search-based period assignment algorithm, an end-to-end laxity-based priority assignment algorithm, and three kinds of schedulability analysis, node, network, and end-to-end schedulability analysis. In addition, this paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system, shows that existing scheduling methods such as Rate Monotonic (RM) scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints, and proposes an end-to-end laxity-based priority assignment algorithm.

• 제어로봇시스템학회논문지
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• 제15권7호
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• pp.742-752
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• 2009

Engineering design involves the specification of many variables that define a product, how it is made, and how it behaves applied to computer, communication and control fields. Before some variables can be determined, other variables must first be known or assumed. This fact implies a precedence order of the variables, and of the tasks of determining these variables consequently. Moreover, design of complex systems may involve a large number of design activities. In this paper, the activity-activity incidence matrix is considered as a representation of design activity analysis which mainly focuses on the precedence constraint with an object of doing IDEF3 in process-centered view. In order to analyze the activity-activity incidence matrix, a heuristic algorithm is proposed, which transforms an activity-activity, parameter-formula, and parameter-parameter incidence matrix into a lower triangular form. The analysis of the structured matrices can not only significantly reduce the overall project complexity by reorganizing few critical tasks in practice, but also aims at obtaining shorter times considering the solution structure by exploring concurrency.