• 대한교통학회지
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• 제28권5호
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• pp.107-116
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• 2010

도심지에서 수요지간의 이동시간은 복잡한 도로사정과 외부환경으로 인하여 실시간 변화하는 교통상황에 큰 영향을 받고 있으며, 수요는 시기나 성향에 따라 확률적으로 변화하고 있다. 대부분의 차량경로문제 연구는 차량경로를 선정함에 있어 수요지간의 이동거리와 평균속력, 확정된 수요를 고려하여 경로를 구성하고 있으며, 교통상황과 확률적인 수요의 동적인 외부환경 반영이 미흡하였다. 본 연구에서는 원활 지체 정체의 교통상황과 확률적인 수요를 고려한 현실적인 차량경로문제를 제안하였다. 수리모형을 구축하고, CPLEX 11.1을 이용하여 검증하였으며, 총 소요시간을 최소화하는 Hybrid 유전자 알고리즘을 제안하였다. 교통상황과 확률적 수요를 고려한 차량경로문제의 결과를 기존의 휴리스틱 알고리즘과 비교하였으며, 본 연구에서 제안한 알고리즘이 가장 우수한 해를 제공하였다.

• Earthquakes and Structures
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• 제9권2호
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• pp.353-373
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• 2015

In this paper, the effects of different types of irregularity along the height on the seismic responses of moment resisting frames are investigated using nonlinear dynamic analysis. Furthermore, the applicability of consecutive modal pushover (CMP) procedure for computing the seismic demands of vertically irregular frames is studied and the advantages and limitations of the procedure are elaborated. For this purpose, a special moment resisting steel frame of 10-storey height was selected as reference regular frame for which the effect of higher modes is important. Forty vertically irregular frames with stiffness, strength, combined-stiffness-and-strength and mass irregularities are created by applying two modification factors (MF=2 and 4) in four different locations along the height of the reference frame. Seismic demands of irregular frames are computed by using the nonlinear response history analysis (NL-RHA) and CMP procedure. Modal pushover analysis (MPA) method is also carried out for the sake of comparison. The effect of different types of irregularity along the height on the seismic demands of vertically irregular frames is investigated by studying the results obtained from the NL-RHA. To demonstrate the accuracy of the enhanced pushover analysis methods, the results derived from the CMP and MPA are compared with those obtained by benchmark solution, i.e., NL-RHA. The results show that the CMP and MPA methods can accurately compute the seismic demands of vertically irregular buildings. The methods may be, however, less accurate especially in estimating plastic hinge rotations for weak or weak-and-soft top and middle storeys of vertically irregular frames.

• 산업경영시스템학회지
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• 제42권4호
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• pp.116-125
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• 2019

The Dynamic Vehicle Routing Problem (DVRP) involves a combinatorial optimization problem where new customer demands become known over time, and old routes must be reconfigured to generate new routes while executing the current solution. We consider the high level of dynamism problem. An application of highly dynamic DVRP is the ambulance service where a patient contacts the service center, followed by an evaluation of case severity, and a visit by a practitioner/ ambulance is scheduled accordingly. This paper considers a variant of the DVRP and proposes a decentralized algorithm in which collaborators (Depot and Vehicle), both have only partial information about the entire system. The DVRP is modeled as a periodic re optimization of VRP using the proposed decentralized algorithm where collaborators exchange local information to achieve the best global objective for the current state of the system. We assume the existence of a dispatcher e.g., headquarter of the company who can communicate to vehicles in order to gather information and assigns the new visits to them. The effectiveness of the proposed decentralized coordination algorithm is further evaluated using benchmark data given in literature. The results show that the proposed method performed better than the compared algorithms which utilize the centralized coordination in 12 out of 21 benchmark problems.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2004년도 춘계학술대회 학술발표 논문집 제14권 제1호
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• pp.111-114
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• 2004

Management of human knowledge is an interesting concept that has attracted the attention of philosophers for thousands of years. Artificial intelligence and knowledge engineering has provided some degree of rigor to the study of knowledge systems and expert systems(ES) re able to use knowledge to solve the problems and answer questions. Therefore, the process of conceptualization and inference of knowledge are fundamental problem solving activities and hence, are essential activities for solving the problem of software ES construction Especially, the access to relevant, up-to-date and reliable knowledge is very important task in the daily work of physicians and nurses. In this study, we propose the conceptualization and inference mechanism for implicit knowledge management in medical diagnosis area. To this purpose, we combined the dynamic knowledge map(KM) and relational database(RDB) into a dynamic knowledge map(DKM). A graphical user-interface of DKM allows the conceptualization of the implicit knowledge of medical experts. After the conceptualization of implicit knowledge, we developed an RDB-based inference mechanism and prototype software ES to access and retrieve the implicit knowledge stored in RDB. Our proposed system allows the fast comfortable access to relevant knowledge fitting to the demands of the current task.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국제학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.1585-1590
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• 1991

This paper presents the principles for design of autonomous systems whose behavior is based on models that support the various tasks that must be performed. We propose a model-based architecture aimed at reducing the computational demands required to integrate high level symbolic models with low level dynamic models. Model construction methods are illustrated to outfit such an architecture with the models needed to meet given objectives.

• 대한산업공학회지
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• 제11권2호
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• pp.47-56
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• 1985

This paper considers a two-product three-facility production planning model, where facility 1 produces product 1 to satisfy its own market requirements and supplies input to facility 2, and facility 2 requires another input from facility 3 (outside supplier). The objective is to determine the optimal production amount in each period in order to satisfy the dynamic demands on time, which minimizes the total cost of production and storage. The set-up cost is incurred jointly from the multi-facility operations.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 1993년도 Fifth International Fuzzy Systems Association World Congress 93
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• pp.985-988
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• 1993

An alternative approach to the design of application-driven fuzzy systems is proposed. A broad class of fuzzy systems applications requires a certain fuzzy partition of the input space while it demands for simple numerical quantities. For this class, a dedicated fuzzy system archictecture is presented and a design strategy is proposed. Both the single-input/single-output and multi-input/multi-output cases are considered. Numerical analysis are complete illustrating several aspects of the proposed framework.

• 대한방사선기술학회지:방사선기술과학
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• 제42권1호
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• pp.53-59
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• 2019

In the field of nuclear medicine, the various static phantoms of international standards are used to assess the performance of the nuclear medicine equipment. However, we only reproduced a fixed situation in spite of the movement of the cardiac, and the demands for dynamic situations have been continuously raised. More research is necessary to address these challenges. This study used flexible materials to design the dynamic cardiac phantom, taking into account the various clinical situations. It also intended to reproduce the images through dynamic cardiac flow to confirm the usefulness of the proposed technique. The frame of dynamic cardiac phantom was produced based on the international standard phantom. A nuclear medicine dynamic cardiac phantom was produced rubber material and silicone implemented by 3D printing technique to reproduce endocardium and epicardium movement. Therefore we compared and evaluated the image of a cardiac phantom made of rubber material and a cardiac phantom made of silicone material by 3D printing technique. According to the results of this study, the analysis of the Summed Rest Score(SRS) showed abnormalities in the image of a cardiac phantom made of rubber material at 10, 20, and 30 stroke rates, but the image of a cardiac phantom made of silicone material by 3D printing technique showed normal levels. And the analysis of the Total Perfusion Deficit(TPD) showed that TPD in the image of a cardiac phantom made of rubber material was higher than that of the image of a cardiac phantom made of silicone material by 3D printing technique at 10, 20, and 30 stroke rates. The potential for clinical application of the proposed method was confirmed in the dynamic cardiac phantom implemented with 3D printing technique. It is believed that the objective information secures the reliability of inspection equipment and it contributes to improve the diagnostic value of nuclear medicine.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.853-860
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• 2011

The societal interest on a faster transportation demands an increase of the train speed over the current operation speed of 350 km/h. However, the dynamic response in the roadbed of concrete track system subjected to the train speed ranging between 300 to 500 km/h has been systematically investigated. Herein, a series of the 2-dimensional numerical simulations using various train speeds were performed. A single wheel was modeled by the rigid body. The rail was attached to the sleepers via linear springs in parallel. The results show that the vertical displacement at the rail and track concrete layer exponentially increases when the train speed increases over 400 km/h. This conclusion implies an existence of the critical train velocity at which the displacement of the track system dramatically increases.

• 한국경영과학회지
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• 제13권2호
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• pp.47-58
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• 1988

The dynamic uncapacitated facility location model is formulated by a mixed integer programming. It has the objective of minimizing total discounted costs for meeting demands specified in different time periods at various demand centers. Costs include those for operation of facilities to demand centers and a fixed cost associated with the capital investment. The problem is decomposed into two simple Lagrangian relaxed subproblems which are coordinated by Lagrangian multipliers. We explored the effect of using the subgradient optimization procedure and a viable solution approach is proposed. Computational results are presented and further research directions are discussed.