• 전기학회논문지
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• 제64권5호
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• pp.830-837
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• 2015

A study which is to develop the low-cost urban railway system for low-density line such as Gwang-ju subway Line 2 is in progress, and its TCS(Train Control System) is required as an economic system which is able to train operation suitable in low-density line. We have developed the signaling equipment which is configured with automatic block system between stations, and the control center's equipment in order to meet the requirements of TCS mentioned above. In this paper, we propose the control procedure of ATS to be required for train operation management in the low-density line such as Gwang-ju subway Line 2. The control procedure of ATS considered all features such as the requirements analysis for train operation management, the functions of train control system to be applied and the block type. Also, it considered the station(interlocking, passenger, turn-back) type, station control(stop, route, departure, turn-back departure, turn-back) type, and train operation management for exiting and entering depot. The ATS control procedure proposed in this paper has an advantage in the cost and efficiency through unification and optimization of its function. And in cost of operating and maintenance, the ATS system has a feature that can be significantly reduced.

• 한국지능시스템학회:학술대회논문집
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• 한국퍼지및지능시스템학회 2007년도 춘계학술대회 학술발표 논문집 제17권 제1호
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• pp.465-468
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• 2007

본 논문은 E-PON 시스템을 통하여 데이터 및 TDM 신호를 전달하기 위한 방안이다. 저가의 이더넷 기술과 광 인프라를 결합한 E-PON 기술은 차세대 액세스 네트워크의 솔루션으로 등장하였다. E-PON의 전송 속도는 1Gbps이며, 다운스트림과 업스트림인 양방향에 대하여 대칭적이다. 따라서 광 IP 이더넷 네트워크 간단한 네트워크 구조, 효율적인 운용, 그리고 낮은 유지비용을 통하여 비용을 상당히 절약할 수 있다. 이와 같은 E-PON 시스템에 TDMoIP(Time Division Multiplexing over Internet Protocol) 모듈을 첨가하고 QoS 제어 기능을 구현함으로써, 이 시스템은 데이터 및 TDM 서비스를 효율적으로 제공할 수 있다.

• 한국정보통신학회논문지
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• 제13권1호
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• pp.186-192
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• 2009

최근 유비쿼터스 컴퓨팅에 대한 연구가 활발해지면서 무선 센서 네트워크는 설치의 용이함과 저렴한 구축비용으로 다양한 분야에 널리 사용되고 있다. 현재 상용화 되어 있는 산간 지역에서 사용가능한 균열 예측 시스템은 구축 방법이나 비용면에서 많은 부담이 되고 있다. 이에 대한 대안으로 저비용의 상용화된 무선 센서 네트워크를 이용한 사면 균열 예측 시스템을 제안한다. 제안 시스템은 센서 노드를 절벽이나 사면, 바위, 둑 등에 부착하기 쉽고 지형물의 원형 손상을 최소화 할 뿐만 아니라 설치 및 유지 보수비용이 기존의 시스템에 비하여 약 50% 정도에 불과한 장점을 갖는다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.116-119
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• 2004

The existing monitoring and control systems of utility-pipe conduit (power tunnel, cable tunnel etc) have established communication lines using optical fiber, leaky coaxial cable (LCX), and several kinds of control cable. Due to the properties of the used media, the cost of equipment is considerably high and the maintenance of the system is difficult. Also, the term of carrying out is long so that the extension of the system is in difficulty. Now it is desirable to adopt Power Line Communication (hereinafter, PLC) technology in the monitoring and control systems and use the existing low-voltage power-line for lamplight as communication line. This will lead the reduction of the construction cost and the easy maintenance of the system. In this paper, we research the characteristics of PLC in conduit, design and manufacture the field test system, and analyze the performance of the system by field test. Then, we introduce the reliable monitoring and control system of utility-pipe conduit using PLC.

• 전력전자학회논문지
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• 제22권3호
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• pp.193-198
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• 2017

This paper discusses the design and control of a switched reluctance motor (SRM) drive system for a built-in car vacuum cleaner. The growing popularity of outdoor activities and recreation has led the automobile industry to expand technologies that increase the convenience of vehicles, and thus, a built-in car vacuum cleaner was introduced. However, the existing DC motor of a vacuum cleaning system has several disadvantages, such as maintenance cost and lifespan issues of its commutator-brush structure. An SRM can be a good alternative to the existing DC motor because of its high-speed capability, long lifespan, low maintenance cost, and high efficiency, among other advantages. A prototype SRM drive is designed and manufactured to verify its feasibility for use in a built-in car vacuum cleaning system. Dynamic simulation is conducted to determine the optimal switching angle for maximum efficiency and minimum torque ripple. Load test, noise measurement, and suction-power tests are also carried out.

• 한국콘텐츠학회논문지
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• 제19권7호
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• pp.421-426
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• 2019

현재 사용자 인증에는 지식기반(ID/PW 등)인증과 생체기반(홍채/지문/정맥 인식 등)인증, 소유기반(OTP, 보안카드 등)인증 등 다양한 종류의 기술을 사용하고 있다. 지식기반 인증인 ID/PW인증 기술은 구현 및 유지 보수 비용이 적게 들며, 사용자에게 익숙한 방식이라는 장점에도 불구하고 해킹 공격에 취약하다는 단점을 가지고 있다. 다른 인증 방식들은 ID/PW인증기술에서의 취약점을 해결하였지만, 초기 구축비용과 유지보수시 비용이 많이 발생한다는 점과 재발급 시 번거로운 문제점을 가지고 있다. 본 논문에서는 기존의 ID/PW기반 인증 기술보다 보안성과 편리성을 증진시키고, 인증에 사용되는 기기에 제약이 없는 사용자 인증을 안전하게 할 수 있는 방안을 제안한다.

• 적정기술학회지
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• 제5권1호
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• pp.8-17
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• 2019

Solar pumps, for water lift systems, is becoming popular in rural areas for supplying drinking water in dry seasons when its need is elevated. The development in technology has also made solar pumps readily available and cheap which has increased its demands. So, for scattered settlements having a limited budget for operation and maintenance costs, solar pump is preferred over grid connected electrical pumping systems. This primary objective of the study was to design a solar photovoltaic pumping drinking water supply system for a small health post which is about 45 km east from Kathmandu, the capital city of Nepal. The study also compared and verified the final design with the system's existing design prepared by a development agency. The water source for this study was a confined aquifer 115m below the surface. The water demand was calculated to be 11m³ per day. A 1500 kPa submersible pump attached to a motor was selected and installed. Along with that twelve solar panels, reservoir, transmission main and distribution main was designed. The outcomes conclude solar photovoltaic pumping water supply systems to be cost-effective with an estimated cost of only USD 0.84 million per MLD. Solar pumps require low maintenance and operation costs and its repairs can quickly be done by the local people. The study also shows that solar technology produces no sound, needs no fuel making it environmentally friendly.

• Investigative Magnetic Resonance Imaging
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• 제23권3호
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• pp.179-201
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• 2019

Portable low-cost magnetic resonance imaging (MRI) systems have the potential to enable "point-of-care" and timely MRI diagnosis, and to make this imaging modality available to routine scans and to people in underdeveloped countries and areas. With simplicity, no maintenance, no power consumption, and low cost, permanent magnets/magnet arrays/magnet assemblies are attractive to be used as a source of static magnetic field to realize the portability and to lower the cost for an MRI scanner. However, when taking the canonical Fourier imaging approach and using linear gradient fields, homogeneous fields are required in a scanner, resulting in the facts that either a bulky magnet/magnet array is needed, or the imaging volume is too small to image an organ if the magnet/magnet array is scaled down to a portable size. Recently, with the progress on image reconstruction based on non-linear gradient field, static field patterns without spatial linearity can be used as spatial encoding magnetic fields (SEMs) to encode MRI signals for imaging. As a result, the requirements for the homogeneity of the static field can be relaxed, which allows permanent magnets/magnet arrays with reduced sizes, reduced weight to image a bigger volume covering organs such as a head. It offers opportunities of constructing a truly portable low-cost MRI scanner. For this exciting potential application, permanent magnets/magnet arrays have attracted increased attention recently. A magnet/magnet array is strongly associated with the imaging volume of an MRI scanner, image reconstruction methods, and RF excitation and RF coils, etc. through field patterns and field homogeneity. This paper offers a review of permanent magnets and magnet arrays of different kinds, especially those that can be used for spatial encoding towards the development of a portable and low-cost MRI system. It is aimed to familiarize the readers with relevant knowledge, literature, and the latest updates of the development on permanent magnets and magnet arrays for MRI. Perspectives on and challenges of using a permanent magnet/magnet array to supply a patterned static magnetic field, which does not have spatial linearity nor high field homogeneity, for image reconstruction in a portable setup are discussed.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.242-248
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• 2007

In this paper, the basic requirements of catenary in railroad traction is explained. Three different types of catenary suspension systems for different terrains, environments and high speed / low speed trains are presented. The essential requirements of catenary such as reliability, cost effectiveness, maintenance and ruggedness requirements are discussed. The catenary materials and safety problems associated in it are dealt.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.141-143
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• 2002

Litrex Ink Jet equipment offers prospect for reliable and low cost manufacturing process for PLED technology. The design concept of 140P system that we are developing meets requirement of process/equipment for PLED manufacturing line in terms of higher mechanical accuracy, in-line monitoring system of print head, high precision of process capability, reasonable through-put, high reliability/easier maintenance and no particle generation.