• Proceedings of the Korean Operations and Management Science Society Conference
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• 1996.10a
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• pp.135-138
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• 1996

In solving the Travel Salesman Problem(TSP), we easily reach local optimal solutions with the existing methods such as TWO-OPT, THREE-OPT, and Lin-Kernighen. Tabu search, as a meta heuristic, is a good mechanism to get an optimal or a near optimal solution escaping from the local optimal. By utilizing AI concepts, tabu search continues to search for improved solutions. In this study, we focus on developing a new neighborhood structure that maintains the feasibility of the tours created by exchange operations in TSP. Intelligent methods are discussed, which keeps feasible tour routes even after exchanging several edges continuously. An extended tabu search model, performing cycle detection and diversification with memory structure, is applied to TSP. The model uses effectively the information gathered during the search process. Finally, the results of tabu search and simulated annealing are compared based on the TSP problems in the prior literatures.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.101-107
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• 2017

Demand for air transportation in Korea keeps increasing, and the number of airport operations also grows as a result. The major two airports in Korea, Incheon International Airport and Gimpo International Airport, share the metropolitan airspace, which is crowd with air traffic. As air traffic increases in the metropolitan airspace, the demand for the airport operations would outnumber the capacities of these airports. However, there is a room to efficiently manage the shortage of the airport capacity due to the different distributions of operations in these airports. This study presents a dynamic slot allocation that allows exchanging slots according to the traffic demand. The dynamic allocation mitigates the airports' capacity problem but the airspace capacity itself should be increased in order to tackle the problem fundamentally.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.11
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• pp.1976-1996
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• 2011

Cognitive radio (CR) MAC protocol provides access control of unused spectrum resources without causing interference to primary users. To achieve this goal, in this paper a TDMA based cooperative multi-channel cognitive radio MAC (MCR-MAC) protocol is proposed for wireless ad hoc networks to provide reliable protection for primary users by achieving cooperative detection of incumbent system signals around the communication pair. Each CR node maintains transmission opportunity schedules and a list of available channels that is employed in the neighbor discovery period. To avoid possible signal collision between incumbent systems and cognitive radio ad hoc users, we propose a simple but efficient emergency notification message exchanging mechanism between neighbor CR nodes with little overhead. Our simulation results show that the proposed MCR-MAC can greatly reduce interference with primary users and remarkably improve the network throughput.

• Korean Management Science Review
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• v.14 no.2
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• pp.19-45
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• 1997

With the proliferation of telecommunication technologies, the traditional internal focus of information systems has shifted to entities beyond the organization's boundaries. In recent years, electronic data interchange (EDI) has come to revolutionize the way in which a business operates and relates to other businesses, Based on the establishment of trading activities, EDI systems have come to signify a speedy, efficient, and accurate means of electronically exchanging business transactions This study examines the current research trends in the area of EDI systems and identifies several issues for future research.55 articles in the EDI area from 1987 through 1996 were collected from related journals and proceedings of conferences. The articles are categorized by years and journals. The amount of EDI research has increased dramatically during the period of the study. Also, presented are the results of a content analysis of the articles. The findings not only provides general information about reserch methods, and direction of EDI study.

• Proceedings of the Korean Information Science Society Conference
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• 2011.06a
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• pp.430-433
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• 2011

본 연구에서는 ISO/IEC JTC1 SC24와 Web3D Consortium에 의해 제정된 국제표준인 H-Anim을 이용하여 캐릭터 애니메이션 교환을 위한 스키마를 정의한다. 기존의 H-Anim 에서는 인간형 캐릭터 구조의 전송이나 저장에 필요한 계층적 데이터 구조를 X3D 기반으로 정의하고 있으나, 생성된 애니메이션을 다른 캐릭터에 그대로 적용할 수 있도록 설계되어 있지는 않다. 본 연구에서는 임의의 H-Anim 캐릭터 모델에 임의의 모션 캡처 데이터를 이용하여 애니메이션을 생성할 수 있도록 H-Anim 에 애니메이션을 정의하는 방법과 이를 기존의 H-Anim 구조에 부합하도록 애니메이션 기능을 위한 스키마 확장에 대해 기술한다. 본 연구에서의 캐릭터 애니메이션 데이터 형식은 서로 다른 응용들 사이에서 애니메이션 데이터를 공유하고 서로 호환성을 갖도록 하는 것을 목적으로 한다.

• Interaction and multiscale mechanics
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• v.1 no.4
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• pp.449-465
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• 2008

In this paper a general approach for studying the motion of a cantilever beam interacting with a 2D fluid flow is presented. The fluid is solved by a general purpose commercial computational fluid dynamics (CFD) package (FLUENT 6.2), while the structure is managed by means of a dedicated finite element method solver, coded in FLUENT as a user-defined function (UDF). A weak fluid structure interaction coupling scheme is adopted exchanging information at the end of each time step. An arbitrary cantilever beam can be introduced in the CFD mesh with its wetted boundaries specified; the cantilever can also interact with specified rigid and flexible walls through use of a non-linear contact algorithm. After a brief review of relevant scientific contributions, some test cases and application examples are presented.

• Journal of the Korean Society of Combustion
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• v.16 no.1
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• pp.46-51
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• 2011

Exhaust gas of an industrial furnace used at such as metallurgy or ceramic manufacturing usually contains thermal energy with high temperature which can be recycled by heat exchanger. However, when the temperature of the exhaust gas is high such as more than $1,000^{\circ}C$, ordinary metallic heat exchanger cannot fully recover the heat due to the limitation of operating temperature depending on the material property. In the present study, a compact ceramic heat exchanger of cross flow type is introduced and evaluated by heat exchange rate and operating temperature. The ceramic heat exchanger can endure the gas temperature more than $1,300^{\circ}C$, and its volumetric heat exchanging rate exceeds 1 MW/$m^3$. The experimental data is also compared with the previous numerical result which shows reasonable agreement. Meanwhile, the gas leakage rate is measured to be about 3~4%, and heat loss to environmental air is about 23~26% of the fuel energy.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.8
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• pp.875-883
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• 1999

서로 다른 기하학적 모델링 시스템에 사용되는 곡선 및 곡면의 자료 교환에서, 시스템이 지원하는 그 곡선 및 곡면의 최대 차수에 제한이 있을 때, 낮은 차수로의 차수 감소가 필요하다. 본 논문에서는 근사 변환에 의한 B-spline 곡선의 차수 감소 방법을 제시한다. 기존의 Bzier 곡선의 차수감소 방법들을 적용하고, 그 방법들을 비교 분석한다. B-spline 곡선의 knot 제거 알고리즘이 자료 감소를 위해 차수 감소 과정에 적용된다.Abstract The degree reduction of B-splines is required in exchanging parametric curves and surfaces of the different geometric modeling systems because some systems limit the supported maximal degree. We propose an approximate degree reduction method of B-spline curves using the existing Bzier degree reduction methods. Knot removal algorithm is used to reduce data in the degree reduction process.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.8
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• pp.67-74
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• 2013

Major utilities have been focusing on R&D and nationwide business of AMI system which plays a vital role in SmartGrid whose concept is to maximize energy efficiency and optimize electric power facility management with exchanging real time information between utilities and consumers based on ICT technologies in power grid. In this paper, we suggest a power loss monitoring method using KEPCO's AMI system which is operating in fields and with the acquisition of AMI data and analyses verify the validation of a power loss monitoring method.

• Journal of the Korean Institute of Rural Architecture
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• v.2 no.1
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• pp.33-46
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• 2000

Go-Sul-Sik(高設式) On-Dol(溫突) houses have a combination of high Ma-Ru and high On-Dol structure. This type of house had been developed in the process of combining Ma-Ru with On-Dol. Go-Sul-Sik On-Dol houses give a clue to unveil exchanging process of Korean On-Dol and Ma-Ru. Go-Sul-Sik On-Dol can be understood as an architectural type of introducing On-Dol into the upper classes' Ma-Ru afterwards. Apparently, Go-Sul-Sik On-Dol houses were not a two-story building. But they had a two-story structure because of On-Dol rooms, which implied a symbolic rank and On-Dol's practicality as well as its being high. Go-Sul-Sik On-Dol houses were peculiar architectural type which realized lives of the very individual authority and symbolic representation within the strict Confucian society. It seemed to be derived from an alternative of the upper classes' architectural culture integrating an ideal into reality.