• 전자공학회논문지S
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• 제36S권9호
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• pp.9-17
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• 1999

본 논문에서는 파일롯 채널(pilot chanel)이 존재하는 직접확산 코드분할 다중접속 방식(DS-CDMA)에서 탐색 창을 갖는 이중도웰 직렬 동기획득 방식에 대한 수학적 모델을 제시하고, 이에 대한 성능을 분석하였다. 성능 분석을 위한 유도된 수학적 모델들은 부호 검출 함수, 오보 함수, 부호 miss함수, 그리고 평균 동기 획득 시간 등이었다. 또한 유도된 식을 IS-95 순방향 링크에 적용하여 수학적 모델에 의한 평균 동기획득 시간을 계산하였고, 이것을 기존의 동기획득 알고리듬과 비교하였다. 그리고 탐색 창을 갖는 이중드웰 직렬 동기 획득 방식에 대하여, 적분 시간과 탐색 창의 크기가 평균 동기획득 시간에 미치는 영향도 분석하였다. 성능분석을 위해 사용된 채널 모델은 북미의 PCS 채널 모델인 JTC 채널로 설정하였다. 성능 분석 결과, 탐색 창을 갖는 이중드웰 직렬 동기획득 방식이 평균 동기획득 시간에서 기존의 동기획득 알고리듬보다 약 17%~25% 정도 단축됨을 보였다.

• 산업경영시스템학회지
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• 제34권4호
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• pp.1-10
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• 2011

This paper addresses the analysis of the travel distance and order picking time of the vehicle in a aisle when items are picked by the batch in a warehouse system. Batching is to combine several orders in a single tour of the storage/retrieval machine. An advantage of batching is that the length of a tour for a batch of orders is shorter than the sum of the individual orders' tour lengths. The average travel distance and order picking time when a batch is picked in a aisle of the warehouse systems are analyzed for the batch size. And when the vehicle is idle, the dwell point of the vehicle to minimize to the response distance is analyzed. As the batch size is increased, average order picking time per item is decreased. The problem is analyzed and a numerical example is showed to explain the problem.

• 건축역사연구
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• 제6권2호
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• pp.53-64
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• 1997

The language of architecture is a kind of tool which helps people to experience the environment not as the thing itself but as a meaningful one. It, gathered by place, constitutes 'genius loci', as the existential structures. It, in other words, gives a thing 'cognitive quality', and serve people to 'dwell' because 'a place is a gathering thing with concrete presence.' Our environment, only when it possesses the language, presents itself as a namable thing or an understood world. Such a meaningful identification is dwelling. The modern world is a complex melting-pot. It is 'complexities' and 'contradiction'. The language of architecture is never created, rather it is selected by needs of the time and the place. In this sense, architectural design means discovery and interpretation of the poetic order of architypal form and style, and the poetic order is a way for people to dwell in the humanistic sense. These reminds me of Martin Heidegger's statement : "Architecture belongs to poetry, and its purpose is to help man to dwell."

• 산업경영시스템학회지
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• 제39권3호
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• pp.30-38
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• 2016

Shuttle-Based Storage/Retrieval System (SBS/RS) is relatively new to industry. The system is in the category of Automated Storage/Retrieval System (AS/RS), but it is different in that the SBS/RS uses shuttles as Storage/Retrieval (SR) machine instead using a stacker crane. The shuttles are assigned to each tier on multi-tier system and operated for pick-up or drop-off order. Since the system can handle multiple orders simultaneously, it can provide much higher throughput than that of general AS/RS with single stocker crane. Thus, this new system is well fit to recent tendency of increasing small quantity batch production and orders. One of the drawback of this system is that it needs a lot of investment to set up. The efficient operation of the system would be one of the critical matters to increase economic efficiency of capital investment. In this study, we focused on the dwell point policy for shuttles to find efficient way of operating the system. There are four basic policies for the dwell point and we had simulation-based experiment for two different scenarios based on the speed of the shuttle and inter-arrival time of the loads coming to the system combined with four different policies. As it was mentioned above, this SBS/RS relatively new to the field and there is no such experiment shown on previous research and the study of dwell point policy for this SBS/RS could provide the direct comparison of each policy with different hardware specification; the capability of the system. The policy that achieves most efficient operation among the given environment is proposed and the usability of the system is discussed.

• 한국ITS학회 논문지
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• 제13권3호
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• pp.25-37
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• 2014

해외 주요 도시에서 운영되고 있는 트램은 도시부의 교통혼잡과 대중교통의 수송분담율 감소 문제, 환경문제를 해결할 수 있는 대중교통 수단으로 인식되어 우리나라의 각 지방자치 단체에서 시스템 도입을 진행 중에 있다. 본 연구에서는 기존 신호운영 체계에서 트램을 효율적으로 운영하기 위한 능동식 트램 우선신호 전략을 개발하였다. 트램 우선신호를 수행하기 위한 시스템을 구성하고, 트램 정류장의 정차시간을 제어를 통해 트램의 교차로 무정차 통과를 구현하는 알고리즘을 개발하였으며, 대향방향의 트램차량을 고려하여 트램의 신호교차로 연속통행을 구현하였다. 또한 트램의 교차로 도착시간에 따라 정류장의 정차시간을 최소화하기 위한 능동식 우선신호 전략을 선택함으로서 신호제어 효과를 극대화 하였다. 개발된 신호제어전략을 평가하기 위해서 VISSIM 모형의 API 기능을 이용하여 트램 우선신호 제어전략을 구현하여 신호제어 효과를 분석한 결과, 트램차량의 신호교차로 정지수와 통행시간이 감소했음을 확인하였고, 일반차량도 트램 우선신호에 따른 지체증가가 거의 나타나지 않음을 확인하였다.

• Journal of Pharmaceutical Investigation
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• 제35권4호
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• pp.243-247
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• 2005

Although many scientists have used pectin, its feasibility in terms of tablet manufacturability with a high speed machine has never been evaluated. Therefore, compactibility of different pectin types for large scale tableting operation has been evaluated. The compactibility behavior of powder pectins was studied by a compaction simulator. It was found that pectin on its own does not produce tablets of acceptable quality even at a punch velocity as low as 20 rpm (e.g. low tensile strengths, capping and lamination irrespective of applied compression force). Thus, dwell time was introduced and more hard compact was produced as relaxation time in die increases. It was concluded that frequent structural failure observed in both pectin types was due to lack of plastic deformation, poor compactibility and high elastic recovery.

• International Journal of Control, Automation, and Systems
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• 제5권5호
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• pp.492-500
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• 2007

This paper focuses on the problem of guaranteed cost control for a class of uncertain linear delay systems with actuator failures. When actuators suffer "serious failure" the never failed actuators can not stabilize the system, based on switching strategy of average dwell time method, under the condition that activation time ratio between the system without actuator failure and the system with actuator failures is not less than a specified constant, a sufficient condition for exponential stability and weighted guaranteed cost performance are developed in terms of linear matrix inequalities (LMIs). Finally, as an example, a river pollution control problem illustrates the effectiveness of the proposed approach.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.673-678
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• 2008

In crushed service areas of Metro railway lines, there are problems such as the buildup discontent, the irregular operation time and rotation of rolling stocks, caused by frequently occurred train delay. Train delay is affected by operation conditions or infrastructure capacities such as train schedule, line capacity, car rotation plan, shunting movements at origin and destination, and also by transport demand characteristics. Furthermore, a delay produce another delays and spread over the following trains. So it is not easy to build up a protection and recovery plan. In this research, we conduct experimental analysis study based on the real metro data, and as a result, present the relation between the traffic demand and the dwell time. And finally, propose future research themes for improving the operation efficiency of metro railways.

• 한국정밀공학회지
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• 제11권6호
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• pp.5-11
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• 1994

We have investigated the variation of dwell and warm-up time for effects of positioning accuracy of the CNC machine tools with an laser measuring system. Also, we strdied the effect of improvement of the positioning accuracy by variation of the temperature for hollow ball screw, which mostly used as drive mechanism of CNC machine tools. We dbtained the effectiveness of cooling effect of the new cooling system, compared with the conventional cooling system.

• 한국전자파학회논문지
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• 제23권6호
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• pp.740-747
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• 2012

최신의 다목적 전투기에 필수적으로 장착되고 있는 능동 위상 배열 레이더(AESA radar, Active Electronically Scanned Array radar)는 스캔 손실(scan loss)로 인해 빔 조향각별 탐지 거리가 불균일하게 나타난다. 빔 조향각별 드웰 시간(dwell time)을 가변함으로써 스캔 손실을 보상할 수 있는 방식이 제시되어 왔으나, 한정된 자원 속에 탐색, 추적, 미사일 유도 등의 다기능을 수행해야 하는 전투기 사격 통제 레이더에서 이러한 방식의 효용성은 종합적인 측면에서 고려되어야 한다. 본 논문에서는 먼저 빔 조향각별 드웰 시간을 가변함으로써, 능동 위상 배열 레이더의 전 탐색 영역에서 균일한 탐색 성능을 도출하였다. 다음으로 고정된 프레임 시간(frame time) 안에 빔 조향각별 드웰 시간을 가변하지 않을 경우의 탐색 부하를 50 %로 가정하면, 균일한 탐색 성능을 위해서는 약 100 %의 시간 자원을 탐색 업무에 할당함으로써, 다기능을 수행해야 하는 전투기 사격 통제 레이더의 요구사항을 만족하지 못함을 나타내었다. 다른 한편으로 균일한 탐색 성능과 50 %의 탐색 부하를 나타내기 위해 프레임 시간을 증가할 경우, 탐색 성능이 기존 대비 86.7 % 저하됨을 보여주었다. 이러한 분석을 바탕으로 프레임 시간, 탐색 부하, 탐색 성능을 종합적으로 고려한 전 탐색 영역 균일한 성능을 갖는 항공기 탑재 능동 위상 배열 레이더의 효과적인 빔 운용 방안을 제시하였다.