• Journal of the Korean Society for Precision Engineering
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• v.17 no.6
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• pp.111-118
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• 2000

The design of reference trajectory with respect to drag acceleration is necessary to decelerate from hypersonic speed safely after atmosphere re-entry of space vehicle. The re-entry guidance design involves trajectory optimization, generation of a reference drag acceleration profile with the satisfaction of 6 trajectory constraints during the re-entry flight. This reference drag acceleration profile can be considered as the reference trajectory. The cost function is composed of the accumulated total heating on vehicle due to the reduction of weight. And a regularization is needed to prevent optimal drag profile from varying too fast and achieve realized trajectory. This paper shows the relations between velocity, drag acceleration and altitude in drag acceleration profile, and how to determine the reference trajectory.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.195-203
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• 2007

In this paper, an analytic model of sleep model operation in the IEEE 802.16e is investigated. A mobile subscribe. station (MSS) goes to sleep mode after negotiations with the base station (BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/1 with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.1260-1263
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• 1987

This paper describes the mobile robot system to recognize the guidance tape, and presents the locomotion algorithm. This system converts video imago to binary image by setting an optimal threshold and obtains the parameters to move the robot. The mobile robot moves according to the programmed route in memory. But after recognized the obstacle on the locomotion routs, this system constructs the new route and the robot moves following the new route.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.859-863
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• 1993

There are two methods to get 3-dimensional information by matching image pair feature-based matching and area-based matching. One of the problems in the area-based matching is how the optimal search region which gives accurate correlation between given point and its neighbors can be selected. In this paper, we proposed a new area-based matching algorithm which uses edge-features used in the conventional feature-based matching. It first selects matching candidates by feature-based and matches image pair with area-based method by taking these candidates as guidance to decision of search area. The results show that running time is reduced by optimizing search area(considering edge points and continuity of disparity), keeping on the precision as the conventional area-based matching method.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.89-94
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• 2004

Many innovative management processes, which are also termed as best practices or value improving practice, have been proven to successfully improve the value of capital facility projects. With a lack of any guidance on how to implement the most suitable value management process for a particular project, the objective of this paper is to facilitate the VMP implementation. A CII (Construction Industry Institute)'s recent study, titled as 'Development of the Value Management Toolkit,' encompasses a comprehensive structure of value management and provides a new methodology in optimizing the implementation of the value management processes in order to leverage the unique project circumstances, such as project objectives, resource availability, and site limitations, etc. As a pioneering study, the findings contribute to the expedition of implementing value management processes in the industry and maximize the potential benefits in applying the most benefiical value management process for a particular capital facility project.

• Journal of Applied Reliability
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• v.17 no.1
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• pp.11-21
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• 2017

Purpose: The occurrence ranks of failure modes can come from the real failure but the severity ranks of failure modes require a highly subjective point of view of users. The severity ranks have to find more objective and scientific values. Methods: We found the optimal values by using the correlation analysis between failure mode effects and the criticality number like RPN (Risk Priority Number) in RCM. Result: This paper shows the result that verified whether the weighted values on each failure effect in criticality number calculation is suitable to the actual failures or not. To get the verification, it used the 5 year data and correlation analysis. Based on the analyzed result, We proposed the more suitable values. Conclusion: This correlation analysis approach can provide guidance of RCM analysis across many industries and situations.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.201-205
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• 2009

We investigated the optimum adhesive thickness for athermalizing an elastomeric lens mount in our space optics application. Theoretical results were compared with finite element solutions using two different models; discrete circular pads and discrete circular pads with columns filling the insertion holes reflecting the reality. A noticeable difference between their optimal thicknesses was observed, and physical interpretation revealed the uncertainty of prevailing athermal equations. A pilot sample was made to check our results and thermo-optical stress was assessed using an interferometer after isothermal load. This study presented insight into preliminary design guidance in elastomeric lens mounting.

• Journal of applied mathematics & informatics
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• v.12 no.1_2
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• pp.233-241
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• 2003

The rolling schedule procedure has been an important part of the Enterprise Resource Planning (ERP) systems. The performance of production planning in an ERP system depends on the selection of the three parameters in rolling schedule procedure: frozen interval, replanning interval, and planning horizon (forecast window). This research investigated, in a theoretical approach, the combined impact of selections of those three parameters. The proven mathematical theorems provided guidance to re-duction of instability (nervousness) and to seek the optimal balance between stability and responsiveness of ERP systems. Further the theorems are extended to incorporate the cost structure.

• 한국지형공간정보학회:학술대회논문집
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• 2002.11a
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• pp.111-116
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• 2002

우리나라 응급의료체계의 구축은 선진국이 1960년대 초 시작한 반면 1980년 이후 구축되기 시작하여 아직까지 미흡한 편이다. 사고 및 재해 발생시 응급환자에 대한 적절한 처치는 관련정보가 빠르게 전달되고, 적절하게 사용되어 응급환자로 하여금 지체시간내에 얼마나 적합한 응급의료서비스를 수혜토록 하느냐가 가장 중요하다. 이를 위해 본 연구는 의료기관, 소방서 등 의료체계의 실태조사를 통하여 현재의 응급의료체계의 현황과 문제점을 분석하였다. GIS를 이용하여 119구급차 등 응급차량이 가는 경로와 일반 시민들이 이용할 수 있는 응급경로탐색에서 많은 영향을 미치는 교통요소, 좌회전, 우회전, 경유지, 시간대별 교통량을 고려하였다. 그리고 환자의 상태에 따른 병원을 찾도록 정보를 제공하였다. 이러한 교통요소 및 병원에 대한 정보를 제공함으로서 보다 나은 환자이송에 최적경로를 제시하고자 하였다.

• Journal of Navigation and Port Research
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• v.30 no.4
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• pp.259-265
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• 2006

This paper presents an improved adaptive neural network autopilot based on our previous study for track-keeping control of ships. The proposed optimal neural network controller can automatically adapt its learning rate and number of iterations. Firstly, the track-keeping control system of ships is described For the track-keeping control task, a way-point based guidance system is applied To improve the track-keeping ability, the off-track distance caused by external disturbances is considered in learning process of neural network controller. The simulations of track-keeping performance are presented under the influence of sea current and wind as well as measurement noise. The toolbox for track-keeping simulation on Mercator chart is also introduced.