• 한국정보과학회논문지:소프트웨어및응용
• /
• 제31권6호
• /
• pp.829-839
• /
• 2004

정수계획법에 기반 한 기법들은 다양한 승무일정계획 최적화 문제를 해결하는 데 매우 효과적인 것으로 알려져 있다. 그러나 정수계획법은 대상 문제의 제약조건 및 목적함수가 모두 선형적으로 표현되어야만 적용이 가능하다는 단점이 있으며 문제의 규모가 클 경우 과도한 수행 시간과 메모리 자원을 요구하게 된다. 반면 이웃해 탐색 기법과 같은 휴리스틱 탐색 기법은 대상 문제의 제약조건이나 목적함수의 형태에 관계없이 쉽게 적응이 가능하다. 그러나 이웃해 탐색 기법은 복잡한 탐색 공간을 탐색할 경우 국소 최적해에 도달한 후 국소 최적해로부터 쉽게 빠져나오지 못하는 경우가 많다. 본 논문에서는 이웃해 탐색 기법과 정수계획법의 장점을 효과적으로 결합하기 위한 방안을 제시하고 있으며 실제 운행중인 지하철 승무일정계획 문제에 적용해 봄으로써 대규모 승무일정계획 최적화 문제에 성공적으로 적용될 수 있음을 확인하였다.

• 한국시뮬레이션학회논문지
• /
• 제3권2호
• /
• pp.57-67
• /
• 1994

For many practical and industrial optimization problems where some or all of the system components are stochastic, the objective functions cannot be represented analytically. Therefore, modeling by computer simulation is one of the most effective means of studying such complex systems. In this paper, with discussion of simulation optimization techniques, a case study in machining process for application of simulation optimization is presented. Most of optimization techniques can be classified as single-or multiple-response techniques. The optimization of single-response category, these strategies are gradient based search methods, stochastic approximate method, response surface method, and heuristic search methods. In the multiple-response category, there are basically five distinct strategies for treating the responses and finding the optimum solution. These strategies are graphical method, direct search method, constrained optimization, unconstrained optimization, and goal programming methods. The choice of the procedure to employ in simulation optimization depends on the analyst and the problem to be solved.

• 대한전자공학회논문지
• /
• 제27권3호
• /
• pp.131-136
• /
• 1990

본 논문에서 게이트레벨 회로의 논리 최적화를 위한 논리적 redundancy조사를 가속화하는 새로운 방법을 제안한다. 게이트레벨 회로의 redundancy 조사문제는 테스트패턴 생성문제와 마찬가지로 유한상태 탐색문제로서, 그 실행시간이 탐색의 크기에 의존한다. 본 논문에서는 효율적인 탐색을 위해, '동적 head line'과 'mandatory 할당' 방법을 제안한다. 동적 head line은 redundancy조사과정에서 동적으로 변경되어, 탐색에서의 backtracking 수를 감소기키며, mandatory 할당은 불필요한 할당을 피할 수 있어 탐색의 크기를 줄인다. 특히 이들 방법은 기존의 테스트패턴 생성문제에서 사용한 방법과는 달리, 회로 최적화에 따른 회로의 변경에 영향을 받지 않고 사용된다. 또한, 이들 방법을 기존의 redundancy 조사시스템에 실현하여, 그 유효성을 보인다.

• 한국정보과학회논문지:소프트웨어및응용
• /
• 제33권7호
• /
• pp.646-654
• /
• 2006

분류검색 방법은 색인검색 방법과 함께 중요한 요소로서 웹 검색 엔진에서 지원되고 있다. 사용자가 분류나 색인검색 방법 중 하나를 이용하여 원하는 검색결과를 찾지 못하면 다른 검색방법을 이용하여 찾을 수 있도록 대부분의 검색엔진에서는 두 가지 방법 모두 지원하고 있다. 색인검색 방법에서는 검색결과의 재현율이 높지만 검색결과가 너무 많이 나오기 때문에 원하는 검색결과를 찾아내는 것이 어렵다는 단점이 있다. 분류검색 방법은 찾고자 하는 문서의 해당 분류가 애매모호하거나 명확하게 알지 못할 때에는 문서를 찾지 못하는 경우가 빈번히 발생한다. 즉, 검색결과의 정확도는 높으나 재현율이 떨어지는 단점이 있다. 본 논문은 이러한 문제점을 해결하기 위해서 분류와 검색어간의 관계를 퍼지논리를 이용하여 정량적으로 계산하고 이를 바탕으로 범주간의 함의관계를 유도함으로써 동적인 범주체계를 구성하는 새로운 방법을 제시한다. 이 방법의 장점은 범주간의 합의관계를 유사한 하위범주로 간주함으로써 분류검색 결과의 재현율을 높일 수 있다는 것이다.

• Journal of Information Processing Systems
• /
• 제9권2호
• /
• pp.315-332
• /
• 2013

This paper presents an approach for improving the use of VP-tree in video indexing and searching. A vantage-point tree or VP-tree is one of the metric space-based indexing methods used in multimedia database searches and data retrieval. Instead of relying on the Euclidean distance as a measure of search space, the proposed approach focuses on the trigonometric inequality for compressing the search range, which thus, improves the search performance. A test result of using 10,000 video files shows that this method reduced the search time by 5-12%, as compared to the existing method that uses the AESA algorithm.

• 한국컴퓨터정보학회논문지
• /
• 제22권7호
• /
• pp.47-54
• /
• 2017

Recently, correlation filter based trackers have shown excellent tracking performance and computational efficiency. In order to enhance tracking performance in the correlation filter based tracker, search area which is image patch for finding target must include target. In this paper, two methods to discriminatively represent target in the search area are proposed. Firstly, search area location is estimated using pyramidal Lucas-Kanade algorithm. By estimating search area location before filtering, fast motion target can be included in the search area. Secondly, we investigate multi-channel Local Edge Pattern(LEP) which is insensitive to illumination and noise variation. Qualitative and quantitative experiments are performed with eight dataset, which includes ground truth. In comparison with method without search area estimation, our approach retain tracking for the fast motion target. Additionally, the proposed multi-channel LEP improves discriminative performance compare to existing features.

• Journal of information and communication convergence engineering
• /
• 제5권3호
• /
• pp.239-244
• /
• 2007

In the telematics system, a reasonable path search time should be guaranteed from a great number of user's queries, even though the optimal path with minimized travel time might be continuously changed by the traffic flows. Thus, the path search method should consider traffic flows of the roads and the search time as well. However, the existing path search methods are not able to cope efficiently with the change of the traffic flows and to search rapidly paths simultaneously. This paper proposes a new path search method for fast computation. It also reflects the traffic flows efficiently. Especially, in order to simplify the computation of variable heuristic values, it employs a simplification method for estimating values of traffic-adaptable heuristics. The experiments are carried out with the $A^*$ algorithm and the proposed method in terms of the execution time, the number of node accesses and the accuracy. The results obtained from the experiments show that the method achieves very fast execution time and the reasonable accuracy as well.

• Journal of Information Technology Applications and Management
• /
• 제13권4호
• /
• pp.121-140
• /
• 2006

UDDI (Universal Discovery Description and Integration) Registry is used for Web Services registration and search. UDDI offers the search result to the keyword-based query. UDDI supports WSDL registration but it does not supports WSDL search. So it is required that contents based search and ranking using name and description in UDDI registration information and WSDL. This paper proposes a retrieval engine considering contents of services registered in the UDDI and WSDL. It uses Vector Space Model for similarity comparison between contents of those. UDDI registry information hierarchy and WSDL hierarchy are considered during searching process. This engine suppports two discovery methods. One is Keyword-based search and the other is template-based search supporting ranking for user's query. Template-based search offers how service interfaces correspond to the query for WSDL documents. Proposed retrieval engine can offer search result more accurately than one which UDDI offers and it can retrieve WSDL which is registered in UDDI in detail.

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2005년도 춘계 학술발표회 논문집
• /
• pp.351-358
• /
• 2005

Many methods have been developed and are in use for structural size optimization problems, In which the cross-sectional areas or sizing variables are usually assumed to be continuous. In most practical structural engineering design problems, however, the design variables are discrete. This paper proposes an efficient optimization method for structures with discrete-sized variables based on the harmony search (HS) meta-heuristic algorithm. The recently developed HS algorithm was conceptualized using the musical process of searching for a perfect state of harmony. It uses a stochastic random search instead of a gradient search so that derivative information is unnecessary In this paper, a discrete search strategy using the HS algorithm is presented in detail and its effectiveness and robustness, as compared to current discrete optimization methods, are demonstrated through a standard truss example. The numerical results reveal that the proposed method is a powerful search and design optimization tool for structures with discrete-sized members, and may yield better solutions than those obtained using current method.

• 대한인간공학회:학술대회논문집
• /
• 대한인간공학회 1993년도 추계학술대회논문집
• /
• pp.124-132
• /
• 1993

This study compared two prediction methods-regression and artificial neural network (ANN) on the visual search performance when monitoring a multi-parameter screen with different occurrence frequencies. Under the highlighting condition for the highest occurrence frequency parameter as a search cue, it was found from the requression analysis that variations of mean search time (MST) could be expained almost by three factors such as the number of parameters, the target occurrence frequency of a highlighted parameter, and the highlighted parameter size. In this study, prediction performance of ANN was evaluated as an alternative to regression method. Backpropagation method which was commonly used as a pattern associator was employed to learn a search behavior of subjects. For the case of increased number of parameters and incresed target occurrence frequency of a highlighted parameter, ANN predicted MST's moreaccurately than the regression method (p<0.000). Only the MST's predicted by ANN did not statistically differ from the true MST's. For the case of increased highlighted parameter size. both methods failed to predict MST's accurately, but the differences from the true MST were smaller when predicted by ANN than by regression model (p=0.0005). This study shows that ANN is a good predictor of a visual search performance and can substitute the regression method under certain circumstances.