• 한국GIS학회:학술대회논문집
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• 한국GIS학회 2010년도 춘계학술대회
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• pp.175-179
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• 2010

본 연구의 목적은 캠퍼스 내 설치된 CCTV의 현황과 설치환경을 파악하고, CCTV의 설치위치 주변 환경 기계적 성능 동을 고려하지 않을 때 발생하는 방범용 CCTV의 설치 및 운용에 문제점을 평가하는데 있다. CCTV의 설치 위치 평가를 위해 네트워크 분석을 활용 했으며, CCTV의 설치환경 분석을 위해서 기계적재원의 확인과 가로등 및 보안등의 조도측정이 이루어졌다. 그 결과 경북대학교 CCTV의 문제점은 크게 학생들의 보행패턴과 무관한 곳에 설치된 지역, 야간 촬영 시 요구되는 조도가 부족한 지역에 설치되어 있음이 확인 되었고, 44대의 CCTV 중 25대만이 범죄 예방이라는 소기의 목적을 위해 활용될 수 있음이 확인되었다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1560-1565
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• 2007

A surveillance system is used many industrial places, and public places to monitor the present situation. Most of the existing surveillance system is composed of the monitors and a lot of cameras that are installed each place to be monitored. The system is usually using the CCTV, closed circuit television, system that is a passive surveillance system. Urban transit operation corporations use the passive surveillance system to monitor the situation of the passengers, and the status of the important facilities. However the officers or operators cannot monitor all of the situation or status constantly, and cannot respond to emergency. In this paper, we propose a sensor network-based intelligent surveillance system to solve these problems. The proposed system is composed of a lot of intelligent sensors that can determine the present status and integrated processor units to detect more precisely events using the information from the sensors. The sensors and the integrated processor are connected by communication network. The proposed system can be installed and used without a lot of change of the existing facilities such as the enormous communication bandwidth increase.

• 상하수도학회지
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• 제29권6호
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• pp.693-702
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• 2015

The objective of this study is to investigate and evaluate that a roadside tree root intrudes sewer network systems. Two approaches were performed to assess the characteristics of tree root intrusion. First, the characteristics of tree roots that had invaded sewers were directly observed by means of closed-circuit television inspection robot. Second, the intrusion proportions of tree root into rain gutters in the sampling area were investigated. As tree species of low intrusion proportions, the results indicated that Ginkgo biloba Linn. and Acer buergerianum Miq. were 1.7% and 4.3%. On the other hand, tree species of high intrusion proportions were Metasequoia glyptostroboides Hu et Cheng, Ulmus davidiana var. japonica Nakai and Zelkova serrata Makino as 22.2%, 20.4%, and 17.6% respectively. In particular, sewers and gutters around Zelkova species should be the focus of maintenance work because of the high proportion of these trees on roadsides.

• 융합보안논문지
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• 제15권1호
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• pp.83-89
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• 2015

다수의 CCTV(Closed Circuit Television)로 광범위한 지역을 관리하는 보안 감시 시스템에서 시간과 장소에 구애받지 않고 CCTV를 원격으로 실시간 모니터링 할 수 있도록 어플리케이션을 설계 및 구현했다. Xcode를 사용하여 개발된 어플리케이션은 폐쇄적인 중앙 관제 시스템으로부터 안전한 관리자 인터페이스를 제공하는 역할을 한다. 효율적이며 직관적인 인터페이스를 통해 어플리케이션은 중앙관제 시스템에서 제공하는 실시간 상황 알림보고 및 상황 인지 추론 결과를 원격의 관리자에게 전달한다. 사용자의 편의를 위해, 어플리케이션은 이벤트 발생시의 push 알림, SNS(Social Network Service) 연동을 포함한 다양한 기능을 제공한다. 실시간 모니터링을 위해 카메라의 화면을 스트림 해줄 서비스는 Wirecast와 Wowza media server를 이용한다. Wowza stream engine은 실시간 스트리밍을 돕는 개발규격에 맞춘 URL을 제공한다. 이를 통해 모바일에서 실시간 스트리밍 결과를 받아 볼 수 있으며, 그 과정에서 발생되는 자원 소모에 관련된 성능분석을 보였다.

• 한국초전도ㆍ저온공학회논문지
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• 제6권2호
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• pp.29-34
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• 2004

The linear type flux pump aims to compensate a little bit decremental persistent current of the HTS magnet in NMR and MRI spectrometers. The flux pump mainly consists of DC bias coil, 3-phase AC coil and Nb foil. The persistent current in closed superconductive circuit can be easily adjusted by the 3-phase AC current, its frequency and the DC bias current. In the experiment, it has been investigated that the flux pump can effectively charge the current in the load coil of 543 mH for various frequencies in 18 minutes under the DC bias of 10 A and the AC of 5 $A_{rms}$. The maximum magnitudes of pumping current and load magnet voltage are 0.72 A/min and 20 ㎷, respectively. Based on simulation results by the FEM are proved to nearly agree with experimental ones.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1027-1028
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• 2008

Most of the urban transit operation company in Korea have a passive surveillance system to monitor the status of the passengers and facilities in the urban transit service area. The surveillance system is based on CCTV, closed circuit television, and several sensors, such as a fire sensor. However, this system has some limitations to prevent and cope with the emergency quickly. So the urban transit operation companies have plans to be change their surveillance system to be active. The active surveillance system has an intelligent function to detect the event predefined by managers automatically. To construct the active surveillance system, there are a standard concept design and a function analysis. In this paper, we propose the classification of the functions of the active surveillance system for urban transit. We divide the functions into five parts, ordinary monitoring, safety monitoring, environment monitoring, administration support, and record management. And we describe the systems related to the every functions to clarify the classified functions.

• Journal of Power Electronics
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• 제16권2호
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• pp.572-583
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• 2016

In view of the speed control characteristics of induction traction motors and the problems of direct torque control (DTC) algorithms in current applications, this paper presents a DTC algorithm characterized by a symmetrical polygon flux control and a closed loop power control in the constant-torque base speed region and constant-power field-weakening region of induction traction motors. This algorithm only needs to add a stator flux control algorithm to the traditional DTC structures. This has the benefit of simplicity, while maintaining the features of traditional algorithms such as a rapid dynamic response, uncomplicated control circuit, reduced dependence on motor parameters, etc. In addition, it obtains a smoother flux trajectory that is conducive to improvement of the harmonic elimination capability, the switching frequency utilization as well as the torque and power performance in the field-weakening region. The effectiveness and feasibility of this DTC algorithm are demonstrated by both theoretical analysis and experimental results.

• 대한전기학회논문지:전력기술부문A
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• 제49권7호
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• pp.359-364
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• 2000

This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

• 시큐리티연구
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• 제51호
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• pp.199-219
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• 2017

이 연구는 초등학교 주변에 설치된 방범용CCTV가 범죄를 감소하는 효과가 있는지를 검증하였다. 이를 위해 춘천시에 설치된 9개의 방범용CCTV의 위치와 종류에 관한 데이터 및 춘천시의 범죄데이터가 수집되었다. 분석단위로 월 단위가 사용되었으며, 날짜, 월평균 온도, 범죄 추이를 통제한 후 포아송 회귀분석을 이용하여 분석하였다. 분석결과는 초등학교 주변에 설치된 방범용CCTV로 인해 전체범죄와 중범죄가 감소하였음을 보여주었다. 그러나 경범죄에서는 그러한 결과가 나타나지 않았다. 본 연구는 방범용CCTV가 초등학교 인근에 설치되었을 때 중범죄율과 전체범죄율을 낮추는 데 도움을 줄 수 있음을 시사한다.

• 한국측량학회지
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• 제32권6호
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• pp.591-597
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• 2014

A wide variety of image application methods, such as aerial image, terrestrial image, terrestrial laser, and stereo image point are currently under investigation to develop three-dimensional 3D geospatial information. In this study, matching points, which are needed to build a 3D model, were examined under diverse weather conditions by analyzing the stereo images recorded by closed circuit television (CCTV) cameras installed in the U-City. The tests on illuminance and precipitation conditions showed that the changes in the number of matching points were very sensitively correlated with the changes in the illuminance levels. Based on the performances of the CCTV cameras used in the test, this study was able to identify the optimal values of the shutter speed and iris. As a result, compared to an automatic control mode, improved matching points may be obtained for images filmed using the data obtained through this test in relation to different weather and illuminance conditions.