• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.6
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• pp.506-515
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• 1990

The major purpose of this thesis is suggest the simulation algorithm for performance analysis of throughput of slotted 1-persistent CSMA/CD bus protocol in Local Area Networks. The suggested simulation algorithm processes the effect of each station group that classified by the number of collision experience. Therefore, this simulation algorithm is more effective in terms of the execute than existing algorithm that processed the effect of each station. This study suggests the method for application to the busy/idle generator.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.53-54
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• 2015

기존의 IEC 61850 표준 적용 국내 디지털변전소는 Station 레벨에 한정되어 구축되어 왔다. 향후 구축될 Process 레벨을 포함한 풀(Full) 디지털 변전소 디지털화는 디지털변전소 운전에 있어 중요하고 긴급한 신호인 Process bus를 통한 SV와 GOOSE신호의 전송으로 이루어지고 있다. Process bus를 활용한 배전선로 보호용 통합 IED는 GIS 등 변전소 전력설비로부터 전압과 전류 값을 MU(Merging Unit)를 통해 공급받아 각 구간의 Bay 혹은 Bank단위로 통합적인 보호 기능을 수행하고, 주 IED와 예비 IED가 서로의 상태를 상호 감시하여 보호기능의 이중화를 이루어야 하고, Sampled Value를 처리하기 위한 정밀한 시각동기화 기능을 갖추어야 한다. 만약, Process bus 시스템의 문제로 인해, 지연과 손실이 발생한다면 변전소 보호 제어에 영향을 줄 수 있으므로 Process bus를 디지털변전소에 적용하기 위해서는 Process bus 기반의 네트워크시스템에 연결된 MU와 IED가 송수신하는 SV와 GOOSE를 손실과 지연없이 전송할 수 있는지를 분석해야 한다. 본 연구에서는 디지털변전소 네트워크 시뮬레이션 시험을 통해, 배전선로용 통합 IED의 성능검증을 위해 Process bus 네트워크 시스템을 설계하고 시뮬레이션 시험을 수행하여 이를 통해 향후 국내의 Process bus 디지털변전시스템 구축을 위한 효과적인 네트워크 시스템 설계방법을 제시하고자 한다.

• Journal of the Korean Society for Railway
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• v.16 no.1
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• pp.59-64
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• 2013

This study analyzed passenger access and egress travel patterns related to a Korean regional railway station (Seoul station), then developed a binomial logit model. This model referred to bus and metro mode of access and egress during a national holiday (Chuseok 2009); obtained from transit smart card data. The results showed that 99% of passengers getting access to, or egress from, the regional railway station did so using less than two transfers, and that most passengers were more likely to choose a metro. However, the passengers that made access or egress trips near Seoul Station were more likely to take a bus. From the results of the mode choice model, it was found that the impact of travel time was greater than that of travel cost, in the choices made for both access and egress. Interestingly, the impact of travel time is much greater in choosing the mode of egress.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1348-1351
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• 1996

In field bus network, field device are connected with a medium. Because a medium must be shared for transmitting data, there are random delay time when data arrive destination station. It is difficult that all data packets are guaranteed synchronization and real-time restriction. In this paper, we show an algorithm that makes network utilization to maximum, guarantees real-time restriction, calculates sampling time at all control loop.

• KIEE International Transactions on Power Engineering
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• v.5A no.4
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• pp.322-330
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• 2005

This paper proposes methods to incorporate station related aging failures in composite system reliability assessment. Aging failures of station components, such as circuit breakers and bus bars, are a major concern in composite power system planning and operation as an increasing number of station components approach the wear-out phase. This paper presents probabilistic models for circuit breakers involving aging failures and relevant evaluation techniques to examine the effects of station related aging outages. The technique developed to incorporate station related aging failures are illustrated by application to a small composite test system. The paper illustrates the effects of circuit breaker aging outages on bulk system reliability evaluation and examines the relative effects of variations in component age. System sensitivity analysis is illustrated by varying selected component parameters. The results show the implications of including component aging failure considerations in the overall analysis of a composite system.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1093-1099
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• 2016

Currently, there are 499 metropolitan subway stations in Korea, but there are not many studies on the influence zone of linkage between railway station and public transport. Existing studies have been studied almost in terms of accessibility.. In addition, the existing research on the influence zone of linkage using survey data and statistics, there is a limit to the theoretical basis and analysis techniques. In this paper, we propose a new method to select on the influence zone of linkage, It is a GIS analysis technique using the spatial data of the railway station user as the large data of the traffic card. We applied the GIS analysis technique for select the influence zone of linkage based on the travel time of the network for each public transportation system. As a result, it was confirmed that the influence of the link of 15 minutes on the local bus, 20 minutes on the city bus and 25 minutes on the intercity bus were clearly distinguished according to the difference in network access time.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.6
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• pp.1-11
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• 2008

As bus is realized by economical, environmental transportation that is available mass transport than car, various policy for improvement of services is achieved. As innovative public transportation systems like BMS (Bus Management System) have established, it is possible to manage bus service efficiently. However, the present bus service management system mainly focuses on enhancing service reliability represented by schedule adherence index. This study discusses the necessity of a special management for bus bunching phenomena at stops, and develops two kinds of bus bunching indices based on the Number of Berth and the Average Bus Arrival Rate. The bus bunching indices were measured by utilizing the bus operational information from BMS at the Seoul TOPIS(Transportation & Information Service). In order to evaluate the sensitivity of the Indices, the indices were applied to two different bus groups: buses on exclusive bus median lane, and regular (shared) lanes. As analysis result, is bunching as is near in downtown and is bunching to peak time morning than the afternoon. Compared with the schedule adherence index, the suggested indices were proved as an efficient complementary indices in the evaluation of the bus operational performance. The results of index comparison between exclusive bus median lane and shared lanes can promote the expansion of exclusive bus median lane. Moreover, it can also be used as a reference in deciding bus station scale including the Number of Berth and the route adjustment plan.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.10a
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• pp.175-177
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• 2022

This paper introduces a system that assists the blind to move to their destination, and compares the performance of 3-types of deep learning network (DNN) used in the system. The system is made up with a smartphone application that finds route from current location to destination using GPS and navigation API and a bus station installation module that recognizes and informs the bus (type and number) being about the board at bus stop using 3-types of DNN and bus information API. To make the module recognize bus number to get on, We adopted faster-RCNN, YOLOv4, YOLOv5s and YOLOv5s showed best performance in accuracy and speed.

• Design Convergence Study
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• v.13 no.5
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• pp.131-145
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• 2014

Considering the number of population commuting from Gyeonggi to Seoul, the development of the bus system is relatively slow. There are many problems to be solved but it has been overlooked, leaving the users in discomfort. The goal of this research is to improve the current system to satisfy the unmet needs, using HCI methods, which is composed of five steps, including Define, Find, Analyze & Synthesize, Ideation, Develop. In Define, we recruited the interviewees using the extreme user method to find their needs. In Find, we proceeded 'be the customer', shadowing for background research and in-depth interview. In Analyze & Synthesis, we analyzed the customer needs and clustered to similar needs to draw useful ideas. After that we suggested sophisticated ideas based on design principles from previous stage and visualized in user scenarios and mock-ups. Overall, the research suggests with text message service, informative light service and mobile application to improve the existing bus station.

• Journal of Korean Society of Transportation
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• v.28 no.1
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• pp.15-24
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• 2010

Until now, the location and the size of gate are designed by only experience and intuitive use judgement. However there are no studies that investigated how many people will be using each subway gate depending on the location of gates. Therefore, the purpose of this study is to develop a gate choice model of subway station. The most critical element of a gate choice in subway station is the location of pedestrian's destinations. In this study, the development of the regression model is constructed from data of land use characteristic of station vicinity and the number of bus route and the space structure of station vicinity(Depth concept by Space Syntax analysis and total road length of station vicinity) by using the real data of 30 subway station in Seoul. This study found that subway pedestrian flow are mainly determined by three factors; the total floor space of commercial buildings, Total Depth(space structure index of station vicinity), and the number of bus route. The verification of a proposed model is done by using the real gate pedestrian data of two subway station in Seoul; Gang-nam and Yang-jae. The additional study of how to define the gate impact area is analysed. Therefore, this study will provide the theoretical bases in decision of gate location and size when a new subway station is opened in future.