• 한국정밀공학회지
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• 제34권3호
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• pp.179-184
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• 2017

Recently, traffic accidents and damage on the highway have increased because of overloaded vehicles. The existing overload-detecting system has a low accuracy rate. An overload-detecting system using a weigh-in-motion (WIM) system has been developed to solve this problem. The WIM system can be used to detect overloaded vehicles by measuring the weight of the vehicles. The WIM system is divided into high-speed and low-speed types. The inaccuracy rate in the low-speed WIM system results mainly from the low response rate of the sensor when the velocity is moving at more than 20 km/h. In this study, a low-speed overload-detecting pad with a hydraulic structure using a WIM system was developed to make the system more accurate. The structural and formal analysis was carried out by using a finite element method (FEM) in order to analyze the structural stability and the extrusion velocity of the system. In addition, a static load test was performed to confirm the linearity and accuracy of the pad.

• 한국주거학회:학술대회논문집
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• 한국주거학회 2011년도 춘계학술발표대회 논문집
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• pp.121-126
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• 2011

This study is a preliminary study to develop design guidelines on shared spaces of apartment for healthy housing. It was tried to set the basic direction of the guideline development by comparing and analyzing related literatures based on the previously identified evaluation indicators of healthy housing of apartment. The major findings were as followings: 1) based on the research conducted before, the characters of shared spaces for healthy housing were classified as physical, mental and social dimensions. 2) According to the comparison and analysis of relevant standards and guidelines, focuses were mostly on the physical dimension, particularly on the human traffic lines of the convenience attributes. Other focuses were on the attractiveness of the apartment complex of the vitality attribute under the mental dimension, and community facilities of the residential stability attributes under the social dimension. Therefore, it was identified that it is required to take complementary measure regarding mental and social dimensions, and design concrete steps to include different attributes of each dimension, in order to develop comprehensive guidelines for shared space.

• 대한토목학회논문집
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• 제8권1호
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• pp.41-48
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• 1988

교량과 같이 지속적인 반복하중을 받는 구조물에서는, 사용년수의 증가에 따라 각 구성요소에는 피로현상이 발생한다. 특히 근간의 교통량의 비약적인 증가로 안한 과대응력의 발생은 강교량의 안전성에 심각한 영향을 부가시켜 주고 있다. 이에 본 논문에서는 실제 교량으로부터의 내하력 조사 자료를 통계 정리하여 강교량의 유지 보수를 보다 효율적으로 수행할 수 있도록 하고 이값들을 매트릭스 구조 해석법을 이용한 수치해와 비교한 후 기존교량의 충격계수를 실측에 의하지 않고서도 개략적으로 예측할 수 있는 기본 방법을 제시하였다.

• 한국생산제조학회지
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• 제22권1호
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• pp.92-99
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• 2013

The ratio of mobility handicapped was 12,110,000 in late 2009 about 24.4% of total population. The number of handicapped population is increasing continuously due to traffic accidents and industrial disasters. Therefore, the purpose of this research is to suggest a design for passengers on wheelchairs to get into and off to raise handicapped or elderly people's right of mobility. The scope of this research is mobility handicapped especially wheelchair passengers who use vans, small buses, and trains. The ramp design of vans is module form. The ramp is moved with screw jack and guides are installed on each side to increase stability. Moreover, a bridge was installed for smooth getting in and off of the van. The ramp design for small bus is lowed by 200m in order not to have obstacle such as speed bump when getting in or off. In order to reduce vulnerable environment and administration, air slide cylinder was chosen. Lastly, for the ramp design of train, the principle of link was used that the simpler structure made the weight lighter and installation in the train became easier. If we look at the conjugation condition of heterogeneous materials to produce a ramp, proper welding condition for cold steel plate and stainless plate is 3kW output and 3-5m/min of welding speed using laser beam seems proper.

• 한국빅데이터학회지
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• 제2권2호
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• pp.129-140
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• 2017

낮은 시정, 강우, 강풍, 고온 등 기상 상태는 운전 능력, 차량 성능(예: 마찰, 안정성, 조작력), 노면 마찰력, 도로 인프라, 추돌 위험, 교통 흐름 및 도로 관리자 생산성 등에 영향을 미친다. 최근에는 CCTV, 도로 센서, 차량 센서 등 다양한 도로 기상 빅데이터 소스들이 개발되면서 이러한 기상 관련 문제들 해결에 적용되고 있다. 본 연구는 이러한 도로 기상 빅데이터 소스들의 유형과 특징을 정의하고 국내외 실증 사례들을 통해 도로 기상 빅데이터 유형별로 관련 문제들 해결에 활용하는 전략에 대해 제시하고자 한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권3호
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• pp.1441-1461
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• 2017

Nowadays, Dynamic Adaptive Streaming over HTTP (DASH) has become very popular in streaming multimedia contents. In DASH, a client estimates current network bandwidth and then determines an appropriate video quality with bitrate matching the estimated bandwidth. Thus, estimating accurately the available bandwidth is a significant premise in the quality of video streaming, especially when network traffic fluctuates substantially. To cope with this challenge, researchers have presented various filters to estimate network bandwidth adaptively. However, experiment results show that current schemes either adapt slowly to network changes or adapt fast but are very sensitive to delay jitter and produce sharply changed estimation. This paper presents a novel bandwidth estimation scheme based on Moving Average Convergence Divergence (MACD). We applied an MACD indicator and its two thresholds to classifying network states into stable state and agile state, based on the network state different filters are applied to estimate network bandwidth. In the paper, we studied the performance of various MACD indicators and the threshold values on bandwidth estimation. Then we used a DASH proxy-based environment to compare the performance of the presented scheme with current well-known schemes. The simulation results illustrate that the MACD-based bandwidth estimation scheme performs superior to existing schemes both in the speed of adaptively to network changes and in stability in bandwidth estimation.

• 융합보안논문지
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• 제2권2호
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• pp.189-198
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• 2002

본 논문에서는 홈 게이트웨이를 이용하는 가입자들을 관리하기 위해 SSL을 이용한 웹 기반 홈 게이트웨이 관리 시스템을 설계하였다. SNMP를 탑재한 홈 게이트웨이의 시스템 분석, 성능 분석, 장애 분석 등을 파악하기 위해 MIB 오브젝트를 추출하여 가공한다. 시스템 분석은 홈 게이트웨이의 기본적인 구성 정보를 제공하고, 성능 분석은 장비의 실시간 트래픽 정보와 상태를 나타내며, 장애 분석은 예외 상황에 대한 장애로그 및 Trap 메시지를 통하여 장애를 통보 받는다. 또한 SSL(Secure Socket Layer)을 이용하여 서버와 클라이언트 사이의 통신 회선의 보안을 강화함으로써 관리 시스템의 안정성을 증가시켰다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 춘계학술대회 논문집 전기설비전문위원
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• pp.195-197
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• 2009

It is a proven fact with the opening of the Seoul metro line number 1 in 1974 traffic congestion on the roads has decreased and the efficiency of people transportation in general has greatly been enhanced in the downtown and surrounding areas of Seoul. Even today construction of new subway lines are under way and many more are being planned due to the easy access to stations, short waiting and average travel times, compared with personal vehicles, contributing to the efficiency of the public transportation systems that are linking the downtown areas and also the intercity systems in moving passengers during rush hour and times of special event. Since the labour costs of the train operator in any large city based subway system accounts for a major part of the operating costs per kilometer and to ensure cost efficient operations, especially during non-peak hours, it is necessary to implement an unmanned(auto-driven) subway system. In order to implement such a system it is imperative that the on-board and wayside signalling control systems be fully automated as well. Only through proper examination of safety procedures not only by the AUGT(Automated Urban Guided Transport)system but also by ail the international standards organizations involved can safely and stability be ensured.

• Journal of Electrical Engineering and Technology
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• 제10권3호
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• pp.740-754
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• 2015

This paper focuses on the reverse blocking busbar protection scheme with aim to improve the speed of its operation and at the same time to increase operational reliability, flexibility and stability of the protection during external and internal faults by implementation of the extended functionality provided by the IEC61850 standard-based protective Intelligent Electronic Devices (IEDs). The practical implementation of the scheme by the use of IEC 61850 standard communication protocol is investigated. The proposed scheme is designed for a radial type of a distribution network and is modeled and simulated in the DigSILENT software environment for various faults on the busbar and its outgoing feeders. A laboratory test bench is built using three ABB IEDs 670 series that are compliant with the IEC 61850 standard, CMC 356 Omicron test injection device, PC, MOXA switch, and a DC power supplier. Two types of the reverse blocking signals between the IEDs in the test bench are considered: hard wired and Ethernet communication by using IEC 61850 standard GOOSE messages. Comparative experimental study of the operational trip response speeds of the two implementations for various traffic conditions of the communication network shows that the performance of the protection scheme for the case of Ethernet IEC 61850 standard-based communication is better.

• 한국통신학회논문지
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• 제38B권4호
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• pp.298-304
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• 2013

일반적으로 위성 시분할다중접속 (TDMA, Time Division Multiple Access) 통신시스템 설계 시 채널감쇄를 반드시 고려 해야하며 위성 통신시스템은 급격한 채널환경 변화에서도 안정적인 네트워크 구성을 위해 실시간 자동 이득제어기 (AGC, Automatic Gain Control)가 필수적이다. 본 논문에서는 위성 TDMA 통신시스템에서 타임 슬롯에 실시간 적용이 가능한 AGC를 제안한다. 제안하는 실시간 AGC 성능을 확인하기 위해 위성 TDMA 시스템을 설계 및 구현하였고 제안하는 AGC 알고리듬을 적용하여 시스템의 비트 오율을 확인하였다. 이 결과는 추후 위성 TDMA 통신시스템의 안정성을 높이는데 유용하게 활용될 수 있을 것으로 예상된다.