• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1204-1212
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• 2008

현재 서울도시철도 5,7,8호선 신호기계실에 설치되어 운영 중인 열차운행 제어 시스템 (L-CTC)는 DOS로 운용되는 컴퓨터를 사용하고 있다. DOS 기반 L-CTC는 H/W의 부품, DOS 운영 체제에서의 S/W 확보 등으로 시스템 확장과 유지보수가 불가능하게 되었다. L-CTC 노후화는 전체 시스템의 운용에 영향을 미치고 있어 시스템의 개량이 필요한 상태이다. 본 연구에서는 L-CTC 컴퓨터 및 HADAX의 기능을 결함허용시스템을 적용한 완전한 이중계로 구현함으로써 기존 이중계 시스템의 문제점을 해결하였으며, 현재 DOS 기반의 O/S로 운영중인 L-CTC 컴퓨터를 WINDOWS 기반의 O/S로 구현하여 L-CTC 컴퓨터에 제어기능을 추가함으로써 기존 LCP제어 방식을 개선하여 장비의 간소화 및 시스템 현대화를 구현하였다. 또한 기존 연동장치인 Microlok의 오류정보를 L-CTC 컴퓨터로 수신하여 운영 중 발생하는 Microlok의 오류 사항에 대하여 효율적인 대처가 가능하도록 하였다. 또한 현장 감시 기능만을 수행하는 분소 시스템에 제어 기능을 추가하여 사령과 현장 기계실 시스템의 중간 단계에 통합분소 시스템을 구축함으로써 사령제어 불가능 시, 통합분소 시스템이 현장 L-CTC 시스템을 통제하도록 구성하여 성능 향상 및 분소와 기계실의 집중화 방안을 제시하였다. 본 논문을 통해 서울도시철도 L-CTC 시스템 장비의 노후화를 대비할 수 있으며, 완전한 이중계 구성으로 시스템을 더욱 안정화 하였다. 또한, WINDOWS 기반의 O/S로 L-CTC 컴퓨터를 구성하여 장비의 간소화 및 현대화가 가능해 졌으며, 분소 및 기계실의 집중화 방안을 제시하여 유지 보수 기능을 향상시켰다.

• 한국분무공학회지
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• 제21권3호
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• pp.121-129
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• 2016

The advantages of the common rail fuel injection system architecture have been recognized since the development of the diesel engine. In common rail systems, a high-pressure pump stores a reservoir of fuel at high pressure up to and above 2000 bar. And solenoid or piezoelectric valves make possible fine electronic control over the fuel injection time and quantity, and the higher pressure that the common rail technology makes available provides better fuel atomization. In this study, the direct needle-driven piezo injector was investigated for accomplishing injection pressure of 1800 bar by optimal design by simplification of component and changing number of springs and plates of DPI. It was found that a direct needle-driven piezo injection system features the prototype DPI for passenger vehicle to operate at 1800 bar of injection pressure.

• 한국정보통신학회논문지
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• 제16권12호
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• pp.2747-2754
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• 2012

본 논문에서 PC 컨텐츠의 활용을 극대화시키는 부가기능을 갖는 다중 LCD(Liquid Crystal Display) 시스템을 개발하였다. 이는 host LCD와 slave LCD로 구성되어 있다. Host LCD는 NTSC(National Television System Committee), PAL(Phase Alternation Line), SECAM(S$\acute{e}$quentiel couleur avec m$\acute{e}$moire) 신호를 받아 영상 및 음성을 데코딩하여 출력한다. 이 데코딩된 신호들을 LVDS(Low Voltage Differential Signaling) 신호로 변환하여 slave LCD단으로 전송을 하는 기능을 갖는다. 그리고 CF 메모리, USB 메모리등을 장착하여 멀티미디어 데이터를 출력하도록 한다. Slave LCD는 host LCD와 달리 튜너부분이 없고 메모리 장착이 되지 않아 자체 TV 신호 수신 및 영상 신호 재생을 하지 못한다. 다만, LVDS 영상 신호를 받아 LCD 팬널에 출력하는 기능만 갖도록 한다. 본 논문에서 개발한 다중 LCD 시스템은 제품이 단순하여 상대적으로 고장률이 낮고, 가격이 저렴하고 제어부분의 간소화로 디스플레이의 전력이 낮으며, host LCD의 채널, 볼륨 및 영상 출력에 대하여 전체 slave LCD를 제어할 수 있는 제품으로서의 가격 및 기능 경쟁력을 갖추고 있다.

• 전기학회논문지
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• 제65권1호
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• pp.31-39
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• 2016

Power system engineers use power systems solution programs such as PSS/E, DSATool, Power World simulators for power system analysis. In this reason, KEPCO has begun to develop independent power system program, KW-PSS(KEPCO World Power system Solution) since 2002 and KW-PSS ver2.0 development was completed in 2011. However, it did not have much better functions compared with other programs. Therefore, we focused on the development of the practical and specialized functions. Consequently, PAZ(Power system AnalyZer) ver3.0 has been developed and it realized a differentiation than previous version. In other words, previous version focused on the basic function of power system analysis, PAZ ver3.0 has implemented many automated functions for power system operators were driven maximize operational efficiency. The unique feature of the implementation is as follows : Automated check for exceeding the breaker capacity, Scheduled outage automation, Control-file wizard for various voltage stability analysis, Scenario-based multiple transient stability analysis and Auto calculation of transmission line impedance. As shown in these functions, Those functions provide to use power system analysis easily by automation and simplification for power system engineers. We will secure national expertise through PAZ ver3.0. In addition it will be able to gain competitive edge through the steady development in the world market.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1528.1-1529
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• 2011

Scribing the transparent conductive oxide(TCO) is an essential technology for the large scaled dye-sensitized solar cell(DSC) and the commercialization of the DSC. Laser systems are most used for scribing technology due to their precision. However, it is difficult to generalize systems because most systems are large and heavy. In this study, we tried to simplificate the Nd:YAG laser system for scribing TCO of the DSC by using switched mode power supply(SMPS) technique. The continuous conduction mode booster converter topology is applied and MC34262 power factor controller is used for the variable frequency control. Finally, SMPS circuit which specifications are 400W of capacity, 400V DC output and 98% of efficiency is fabricated. And it is demonstrated that the scribing TCO is completed by the Nd:YAG laser using this SMPS circuit.

• Journal of Advanced Marine Engineering and Technology
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• 제40권5호
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• pp.418-428
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• 2016

In this study, a Vessel Shore Report Management System (VSRMS) is developed for the International Maritime Organization (IMO), Maritime Service Portfolio (MSP) Number 8, which comprises vessel shore reporting. Several documents have to be completed before the arrival/departure of a vessel at a port, as each national port has its own reporting format and data. The present vessel reporting system is inefficient, time-consuming, and involves excessive paperwork, which results in duplications and errors. To solve this problem, in this study, the vessel reporting formats and data contents of various national ports are investigated, as at present, the reporting documents required by the current IMO standard includes insufficient information which is requested by national ports. Initially, the vessel reporting information of various national ports are collected and analyzed. Subsequently, a database structure for managing vessel reporting data for ports worldwide is devised. To make the transfer of data and the exchange of information of vessel reports much more reliable, efficient, and paper-free, VSRMS, which is a software application for the simplification and facilitation of vessel report formalities, is developed. This application is developed using the latest Microsoft C#.Net Programming Language in the Microsoft Visual Studio framework 4.5. It provides a user interface and a backend MySQL server used for database management. SAP Crystal Reports 2013 is used for designing and generating vessel reports in the original report formats. The VSRMS can facilitate vessel reporting and improve data accuracy through the reduction of input data, efficient data exchange, and reduction of the cost of communication. Adoption of the VSRMS will allow the vessel shore reporting system to be automated, resulting in enhanced work efficiency for shipping companies. Based on this information system and architecture, the consensus of various international organizations, such as the IMO, the International Association of Marine Aids to Navigation and Lighthouse Authorities (IALA), the Federation of National Associations of Ship Brokers and Agents (FONASBA), and the Baltic and International Maritime Council (BIMCO), is required so that vessel reporting is standardized internationally.

• Journal of Microbiology and Biotechnology
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• 제12권3호
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• pp.382-388
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• 2002

In order to assess the effects of organic fertilizer on soil microbial community structure and diversity in the greenhouse fields, fatty acid methyl ester (FAME) was analyzed by the MIDI (Microbial ID, Inc., Newark, DE, U.S.A.) system and enumerations were performed. In relation to bacterial division of each sample, low GC Gram-positive bacteria were predominant among bacteria cultured on aerobic bacteria media. On the other hand, alpha subdivision was predominant on proteobacteria of control and OM (organic matter) 1 treated plot, and Flavobacterium spp. existed in OM2 plot on crystal violet media of all samples. Shannon-weaver Index (H) of OM1 plot varied most by 1.9 and 5.0 among bacteria cultured on aerobic bacteria media and crystal violet media, respectively. Our results revealed that addition of the organic wastes to soil led to a highly diverse microbial community, but the excessive amounts of organic and mineral fertilizer applied in the greenhouse fields produced excess nutrients in soil and led to simplification on bacterial populations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.634-637
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• 1997

This paper is on the research and development of new SIV(Static Inverter) using IGBT(Insulated Gate Bipolar Transistor) semiconductor for a wide range of electric railway applications. For the simplification and higher controllability, the direct PWM control method with 3level inverter topology was adopted. In the new SIV system, the cost as well as bulk and weight was appreciably reduced about 40% lower than those of conventional SIV, the electrical efficiency was increased above 95% and the audible noise level was less than 65dB. In addition, the THD(Total Harmonic Distortion) factor was below 5% and the voltage fluctuation on a transient state was below 10%.

• 한국통신학회논문지
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• 제40권5호
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• pp.871-885
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• 2015

본 연구에서는 우선 고속으로 태그 수집을 위한 2.4 GHz 능동형 RFID 시스템의 시뮬레이션 모델을 구축 하였다. 그리고 단순화 된 Collection 명령과 Ack 절차, 슬롯의 충돌 확률(k1)과 충돌이 발생한 슬롯의 평균 태그 수($k_2$)를 이용하여 태그수를 예측하는 새로운 방법을 제안하였다. 이들에 따른 능동형 RFID 시스템의 성능 추적을 구축한 시뮬레이션 모델을 통해 획득하였다. Query 명령을 사용하여 Collection 명령과 Ack를 간소화하고 $k_1$과 $k_2$를 이용하여 태그수를 예측하는 방법의 조합이 모든 성능 면에서 가장 우수한 것으로 나타났다. 이는 Query 명령을 이용한 Collection 명령과 Ack의 간소화는 태그 인식 속도를 줄이는데 기여했고 $k_1$과 $k_2$를 이용하여 태그수를 예측하는 방법은 Throughput을 향상시킬 뿐만 아니라 이로 인해 Collection 라운드 횟수를 줄여 태그 인식 속도를 줄일 수 있었다. 본 연구에서 제안한 방법은 Throughput, 평균 인식 시간, 1초 안의 평균 인식률 모두에서 이상적인 경우의 성능값과 매우 유사하게 나타나 제안한 방법의 유효성을 확인 할 수 있었다.

• International Journal of Control, Automation, and Systems
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• 제1권3호
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• pp.339-350
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• 2003

In this paper, we propose a simultaneous multithreading (SMT) architecture that improves instruction throughput by exploiting instruction level parallelism (ILP) and thread level parallelism (TLP). The proposed architecture issues and completes instructions belonging to the same thread in exact program order. The issue and completion policy greatly reduces the design complexity and hardware cost of our architecture, compared with others that employ out-of-order issue and completion. On the other hand, when the instructions belong to different threads, the issue and completion orders for those instructions may not necessarily be identical to the fetch order. The processor issues instructions simultaneously from multiple threads to functional units by exploiting ILP and TLP, and by dynamic resource sharing. That parallel execution notably improves performance and resource utilization with minimal additional hardware cost over the conventional superscalar processors. This paper proposes an SMT architecture with grouping as well as one without grouping. Without grouping, all threads dynamically and flexibly share most resources. On the other hand, in the SMT architecture with grouping, in which resources and threads are divided into several groups for design simplification, resources are shared only among threads belonging to the same group as those resources. Simulation results show that our processors with four and eight threads improve performance by three or more times over the conventional superscalar processor with comparable execution resources and policies, and that reasonable grouping reduces the design complexity of SMT processors with little negative effect on performance.