• 한국통신학회논문지
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• 제19권7호
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• pp.1256-1271
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• 1994

본 논문에서는 Gbit 매체접근데어 프로토콜인 HMR(High-speed Multimedia Ring)의 퀘타 할당방법을 변형 적용하여 B-ISDN의 GFC(Generic Flow Control) 프로토콜로 제안하고 시뮬레이션을 통하여 제안된 프로토콜의 성능을 분석하였다. HMR 프로토콜은 Gbit ATM-LAN으로 제안되었지만 버스, 링, 스타버스 형태의 토폴로지에 적용할 수 있도록 고려되었을뿐 아니라 멀티미디어 트래픽 수용을 위한 다단계의 우선순위 제어기능을 가지고 있으므로 수정없이 GFC 프로토콜로 적용이 가능하다. 그러나 기존의 HMR 프로토콜에서 제안되었던 정적퀘타할당 방법은 버스트성이 큰 트래픽에 대하여는 엑세스지연이 과다하게 되는 단점이 있었다. 따라서 본 논문에서는 큐의 크기를 고려한 동적퀘타할당 방식을 적용한 HMR 프로토콜을 제안하고 CCITT에서 제안한 7사지 GFC 시험절차를 적용하여 시뮬레이션을 수행하였다. 동적 퀘타할당 방식을 적용한 HMR 프로토콜은 정적퀘타할당 방식을 적용한 HMR에 비하여 개선된 성능을 나타내었다. 또한 HMR-GFC 프로토콜은 ATMR에 비하여 우수한 성능을 나타내며, DQDB와는 대등한 정도의 성능을 나타탬을 확인하였다.

• 한국통신학회논문지
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• 제40권7호
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• pp.1441-1449
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• 2015

무선 USB (universal serial bus) 시스템은 기존의 USB 기술과 WiMedia PHY/MAC 기술을 결합한 새로운 기술이다. 무선 USB 시스템은 기존의 USB와 같은 개인 영역 네트워크 뿐만 아니라 무선 개인 영역 네트워크에서도 적용될 수 있다. 다수의 무선 USB 네트워크들은 각각의 어플리케이션을 위해 독립적으로 형성되고 동작할 수 있기 때문에, 인접한 네트워크간 간섭이나 충돌이 발생할 수 있다. 이러한 문제를 해결하기 위해, 슈퍼프레임내 다른 시간 구간을 이용하는 방법을 사용할 수 있다. 하지만, 네트워크의 수가 많아지게 되면, 이용 가능한 자원이 부족하게 된다. 따라서, 본 논문은 무선 USB 시스템을 위한 간섭회피 기법을 제안한다.

• 한국ITS학회 논문지
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• 제8권3호
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• pp.20-26
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• 2009

최근에는 각 지자체별 BIS(Bus Information System)/BMS(Bus Management System) 및 ITS(Intelligent Transportation Systems)을 도입함에 따라 시설물 주차 및 노변주차를 무인으로 운영하여 운영구간의 불법행위는 줄어들고 있으나 주변지역의 주차난은 더욱 심각해지고 있으며 단속에 의한 운영으로 시민들의 의식 개선 효과는 미비한 실정이다. 그러므로 주차시설의 관리 및 운영의 효율성, 사용자의 편의성 향상 시켜 근본적인 주차시설 부족을 해결할 필요가 있다. 본 논문에서는 우선 선진국의 주차관리 및 운영체계 현황에 대해 분석하고 다음으로 국내 여건에 맞는 노변주차 운영방식 및 시스템을 설계 한다. 마지막으로 시스템 개발시 기반이 되는 요구조건을 제시하였다.

• 복식문화연구
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• 제21권2호
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• pp.167-182
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• 2013

The purposes of this study were to identify dimensions of shopping orientation and preferences of fashion trade areas, to test differences in the preference factors and usage levels of fashion trade areas as determined by shopping orientation and demographic characteristics. Questionnaires were administered to 406 adults in their twenties and thirties visited major fashion trade area in Seoul. The results of the study were as follows. First, five groups were identified based on shopping orientation: combined value-oriented group, convenience-oriented group, hedonic value trend-oriented group, economic-value oriented group and brand-oriented group. Second, the most frequently visited trade area was Myungdong, and there were significant differences in the usage levels of the trade areas except Dongdaemun, Samsung station COEX, Jamsil and Gangnam Express Bus Terminal among the groups determined by shopping orientation. Sinsa Garosoogil, Apgujeong Chungdam and Samsung Station COEX were preferred by hedonic value trend-oriented group. Daehakro and Myungdong were preferred by combined value-oriented group and convenience-oriented group. Third, significant differences were also found in all groups in the preference factors of the trade area as determined by shopping orientation groups when purchasing clothing. Forth, female preferred Gangnam Express Bus Station and Jamsil than male did. Those who in their early twenties preferred Daehakro and Myungdong the most and those who in early thirties and late twenties concerned service policy the most. The results imply that the consumers tend to visit the nearest fashion trade area by their residence(or work, school) and consider the location and accessibility of the trade area as the most important factor.

• 전기학회논문지P
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• 제63권4호
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• pp.361-367
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• 2014

This paper is related to a new solar power conditioner for a built-in step-up chopper function. In the first step-up chopper proposed solar PV power conditioner for mutually connected in series with the input voltage of the bypass diodes are respectively connected to the positive terminal should install the mutual boosting chopper diode connected in series with the boost chopper switching element between the two power supply and at the same time the first and the second was connected to a second diode and a resonance inductor and a snubber capacitor in series with each other. And the common connection point between the bypass diode and the step-up chopper and the step-up chopper diode common connection point of the switching elements of the input voltage was set to the boost inductor for storing energy. In addition, between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point of the first auxiliary diode and the second common connection point of the auxiliary diode was provided, the resonance capacitor. Between the step-up chopper and the step-up chopper diode and a switching element of a joint connection point and the common connection point of the resonance inductor snubber capacitor and connecting the third secondary diode, between two power supply lines is characterized by configuring the DC link capacitor bus lines in parallel. Therefore, it is possible to suppress the switching loss through, DC link bus lines, as well as there could seek miniaturization and weight reduction of the power conditioner itself by using a common capacitor of the non-polar non-polar electrolytic capacitor having a capacitor, the service life of the circuit can be extended and it is possible to greatly reduce the loss can be greatly improve the reliability of the product and the operation of the product itself.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2021년도 추계학술발표대회
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• pp.1290-1293
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• 2021

현재 시각장애인들의 일상생활에 있어 많은 불편함을 겪고 있어 시각장애인에게 도움이 되고자 실시간 객체인식을 하여 보행환경의 정보를 전달하는 안경을 만드는 프로젝트를 진행하였다. 핵심 기능에 해당하는 객체인식은 인공지능 모델 YOLOv4가 사용되었으며, 시각장애인의 입장에서 걸어 다닐 때 인식 되어야 하는 객체들을 선정하고, 이들을 대상으로 학습 데이터를 재구성하고 YOLOv4의 재학습을 진행하였다. 학습 결과 모든 객체들에 대한 정확도는 68%를 보였으나 시각 장애인이 걸어다닐 때 인식되어야 하는 필수객체(Person, Bus, Car, Traffic_light, Bicycle, Motorcycle)들의 인식률은 84%로 측정되었다. 향 후 진행될 학습에선 더욱 다양한 방법으로 학습데이터를 확보하고, YOLOv4가 아닌 darkflow를 이용해 다양한 parameter로 학습을 진행하여 다면적인 성능비교가 필요하다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1743-1753
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• 2011

Seoul Metropolitan Government has performed alternative transit system, light rail transit(LRT), for settling the problems of urban public transit system based on conventional bus service and heavy rail transit(HRT). LRT projects of total 8 lines(about 73.6km), including Ui-Sinseol line, have been planned as Build-Transfer-Operate(BTO) projects. For the first LRT, Ui-Sinseol line, however, design of structure had met standard for design of HRT, because of no domestic design code for LRT when participates of Ui-Sinseol project submitted the design proposal. This case study reports a successful example of LRT design minimizing the scale of stations designed in base of HRT code. The problems, like oversized structures compared with LRT vehicles, excessive costs for construction, had been resolved through negotiations with the participates of Ui-Sinseol line. Result suggests that present and future costs for construction and maintenance of the LRT projects in Seoul be considerably reduced in advance.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.680-683
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• 1997

Fieldbus system should be designed by considering the number of sensors/actors(actuators+ controllers) and their sampling times. But the number of sensors/actors and which are connected to the network bus can be varied by addition and/or fault of the field devices. That variation decreases the efficiency of system which is off-line designed optimally. This paper proposes an algorithm that ensures transmission of cyclic data even though there is the number change in the field devices. We assign the different weight values to cyclic data and acyclic data. By simulation and experiment, the cyclic and acyclic data are processed via the proposed network, and the results are compared with those of the Profibus system. It is shown that the proposed algorithm is more robust with the uncertainties of the field devices of the control system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.687-689
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• 2004

As using of network increases rapidly, performance of system has been deteriorating because of the overhead and bottleneck. Nowadays, High speed I/O network standard, that is a sort of PCI Express, HyperTransport, InfiniBand, and so on, has come out to improve the limites of traditional I/O bus. The InfiniBand Architecture(IBA) provides some protocols to service the applications such as SDP, SRP and IPoIB. In our paper, We explain the architecture of IPoIB (IP over InfiniBand) and its features in channel based I/O network. And so we provide a performance evaluation result of IPoIB which is compared with current network protocol. Our experimental results also show that IPoIB is batter than TCP/IP protocol. For this test, We use the dual processor server systems and Linux Redhat 9.0 operating system.

• 한국안전학회지
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• 제14권2호
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• pp.70-76
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• 1999

In this paper, a mixed-integer programming approach is presented for adjusting the voltage profiles in a power system. The advent of large-scaled system makes the reactive power and voltage problem-an attempt to achieve an overall improvement of system security, service quality and economy-more complex and seriously, Although the problem is originally a nonlinear optimization problem, it can be formulated as a mixed integer linear programming(MILP) problem without deteriorating of solution accuracy to a certain extent. The MILP code is developed by the branch and bound process search for the optimal solution. The variable for modeling transformer tap positions is handled as discrete one, and other variables continuous ones. Numerical data resulting from case study using a modified IEEE 30 bus system with outaged line show that the MILP can produce more reductions of magnitude in the operating cost. The convergence characteristics of the results are also presented and discussed.