• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1441-1444
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• 2000

실시간 정보가 알려지지 않은 해저환경에서 자율수중 운동체(AUV, Autonomous Underwater Vehicle)가 성공적인 임무 수행을 완료하기 위해서는 주어진 목표지점까지의 안전하고 효율적인 경로설정이 선행되어야 한다. 이를 위해 평가함수(evaluation function)에 기반한 휴리스틱 탐색(heuristic search)이 사용되는데 대부분의 평가함수는 목표점까지의 거리, 소모되는 연료로 구성된다[1]. 본 논문에서는 영역전문가가 보유한 장애물회피 관련 경험적 정보(heuristic information)를 반영하여 보다 효율적인 평가함수를 고안하며 후보노드들간의 관계성을 고려한 퍼지관계곱(Fuzzy Relational Products) 기반 휴리스틱 탐색기법을 제안한다. 제안한 탐색기법의 성능을 검증하기 위해 수행시간(cpu time), 경로의 최적화(optimization)정도, 사용 메모리 관점에서 시뮬레이션을 통해 $A^*$ 탐색기법과 비교한다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.2
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• pp.141-150
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• 2004

Recently, it is really concerned about corrosion and aging of reinforced concrete bridges. Corrosional steel reinforcing in concrete affects not only safety of bridges structure but also bending strength of reinforced concrete's member. Rate of corrosion, characteristic of bending strength, and economical evaluation aren't clear in reinforced concrete, considering performance evaluation. The purpose of study is as follows. It studies about ability of resistance's strength and cost of life cycle according to reduction of steel reinforcing's corrosion. Moreover, it shows calculating formula of bending strength with corrosion of current rate and exactly evaluates about the rest life at corrosional reinforced concrete bridges.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.183-188
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• 2008

Engine control/performance model for helicopter simulator is one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the engine designers/manufacturers. The approaches in this study were to develop the basic model based on the available resources and to tune and verify it based on the ground/flight test results. The maintenance manuals of TB3-117 which is installed in KA-32T were reviewed and the components to be simulated for the engine control model were categorized and modeled. Piece-wise linear modeling method was used for the engine performance model. The engine performance data in the engine maintenance manuals were incorporated into the engine steady state performance tables, which were incorporated with the transfer functions for the dynamic performance. Engine control/performance model was compared and tuned with the ground/flight test results. It was verified that the fidelity of the model was within the tolerances in FAA AC120-63.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2239-2246
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• 2008

Engine control/performance model for helicopter simulator if one of the most important models which affect flight performance and handling quality. It is typical to develop the model based on the raw data and models from the engine designers/manufacturers. The approaches in this study were to develop the basic model bated on the available resources and to tune and verify it based on the ground/flight test results. The maintenance manuals of TB3-117 which is installed in KA-327 were reviewed and the components to be simulated for the engine control model were categorized and modeled. Piece-wise linear modeling method was used for the engine performance model. The engine performance data in the engine maintenance manuals were incorporated into the engine steady state performance tablet, which were incorporated with the transfer functions for the dynamic performance. Engine control/performance model was compared and tuned with the round/flight test results. It was verified that the fidelity of the model was within the tolerances in FAA AC120-63.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.645-645
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• 2015

기존 홍수예보에 사용되는 일반적인 절차는 관측되는 강우를 이용하여 유역의 유출량을 계산하고 댐 저수량과 현 상황에서 발생할 수 있는 하천의 수위와 유량을 판단한 뒤 홍수예보 및 경보를 발령한다. 이러한 방법은 모형의 구동에 걸리는 시간으로 인한 의사결정 시간의 단축, 모형의 성능에 의존하는 홍수예측 결과 등의 단점이 존재하며, 관련 전문가가 상주하며 홍수 유무를 판단하고 상황을 전파해야하는 인적 재원이 필요하다. 본 연구에서는 분포형 강우-유출모형 기반의 강우강도-지속시간-홍수량(IDQ) 곡선을 활용하여 미계측 유역 홍수예보에 활용하는 기법을 평가하였다. 계측된 유역의 자료를 이용하여 분포형 모형의 검보정을 실시하고 하천의 예경보 홍수량에 준하는 한계강우량을 산정하였다. 이때. 다양한 지속시간의 강우를 적용하였으며 토양함수상태에 따른 IDQ 곡선을 산정하여 발생 가능한 여러 시나리오에 대비할 수 있는 홍수예보 기법을 제시하였다. 주요 홍수예경보지점에 적절한 IDQ 곡선을 보유하게 된다면 비전문가도 신속한 홍수예경보 의사결정이 가능하여 각 지자체와 유관기관에서 손쉽게 활용할 수 있으리라 판단된다.

• Journal of the Korean Society for Nondestructive Testing
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• v.17 no.3
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• pp.162-173
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• 1997

Automatic on-line surface inspection systems have been applied for monitoring a quality of steel strip surfaces. One of the important issues in this application is the performance of on-line defect classifiers. Rule-based classification table methods which are conventionally used for this purpose have been suffered from their low performances. In this work, probabilistic neural networks and the enhanced classification tables which are newly proposed here are applied as alternative on-line classifiers to identify types of surface defects on cold rolled strips. Probabilistic neural networks have shown very excellent performance for classification of surface defects.

• Journal of KIISE:Software and Applications
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• v.29 no.1_2
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• pp.91-97
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• 2002

This paper describes a heuristic search technique carrying out collision avoidance for Autonomous Underwater Vehicles(AUVs). Fuzzy relational products are used as the mathematical implement for the analysis and synthesis of relations between obstacles that are met in the navigation environment and available candidate nodes. In this paper, we propose a more effective evaluation function that reflects the heuristic information of domain experts on obstacle clearance, and an advanced heuristic search method performing collision avoidance for AUVs. The search technique adopts fuzzy relational products to conduct path-planning of intelligent navigation system. In order to verify the performance of proposed heuristic search, it is compared with $A^*$ search method through simulation in view of the CPU time, the optimization of path and the amount of memory usage.

• The Korean Journal of Applied Statistics
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• v.35 no.2
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• pp.229-250
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• 2022

Since the publication of Markowitz's (1952) mean-variance portfolio model, research on portfolio optimization has been conducted in many fields. The existing mean-variance portfolio model forms a nonlinear convex problem. Applying Dantzig's linear programming method, it was converted to a linear form, which can effectively reduce the algorithm computation time. In this paper, we proposed a Dantzig perturbation portfolio model that can reduce management costs and transaction costs by constructing a portfolio with stable and small (sparse) assets. The average return and risk were adjusted according to the purpose by applying a perturbation method in which a certain part is invested in the existing benchmark and the rest is invested in the assets proposed as a portfolio optimization model. For a covariance estimation, we proposed a Gaussian kernel weight covariance that considers time-dependent weights by reflecting time-series data characteristics. The performance of the proposed model was evaluated by comparing it with the benchmark portfolio with 5 real data sets. Empirical results show that the proposed portfolios provide higher expected returns or lower risks than the benchmark. Further, sparse and stable asset selection was obtained in the proposed portfolios.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.183-192
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• 2022

With the growth of the packaging industry, demand on the packaging printing comes in various forms. Customers' orders are diversifying and the standards for quality are increasing. Offset printing is mainly used in the packaging printing since it is easy to print in large quantities. However, productivity of the offset printing decreases when printing various order. This is because it takes time to change colors for each printing unit. Therefore, scheduling that minimizes the color replacement time and shortens the overall makespan is required. By the existing manual method based on workers' experience or intuition, scheduling results may vary for workers and this uncertainty increase the production cost. In this study, we propose an automated scheduling method of parallel offset printing process for packaging printing. We decompose the original problem into assigning and sequencing orders, and ink arrangement for printing problems. Vehicle routing problem and assignment problem are applied to each part. Mixed integer programming is used to model the problem mathematically. But it needs a lot of computational time to solve as the size of the problem grows. So guided local search algorithm is used to solve the problem. Through actual data experiments, we reviewed our method's applicability and role in the field.