• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1465-1466
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• 2006

The monitoring and diagnosing technique for lightning arresters is important to assure the reliability of power supply in GIS-substation. In this paper, we described the implementation of an expert system for GIS arrester facilities. The proposed system consists of a data acquisition module (DAM), a wireless communication module, and a personal computer. The DAM detects system voltages, total leakage currents and its harmonic components, and includes an algorithm to calculate the resistive leakage current by the principle that the magnitudes of resistive leakage current are equal at the same level of the system voltage applied to the arrestor. Also, we designed a surge event detection circuit which can acquire the date, the polarity, and the amplitude of surge events. All the acquired data are transmitted after correction by many algorithms to the remote station through the ZigBee protocol. The expert system is based on the Jave Expert System Shell (JESS) and make more reliable decision by using an exclusive inference process.

• Applied Microscopy
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• 제46권4호
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• pp.206-216
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• 2016

This communication is to elucidate the state-of-the-art of techniques necessary to gather information on a new class of nanoelectronic devices known as memristors and related resistive switching devices, respectively. Unlike classical microelectronic devices such as transistors, the chemical and structural variations occurring upon switching of memristive devices require cutting-edge electron microscopy techniques. Depending on the switching mechanism, some memristors call for the acquisition of atomically resolved structural data, while others rely on atomistic chemical phenomena requiring the application of advanced X-ray and electron spectroscopy to correlate the real structure with properties. Additionally, understanding resistive switching phenomena also necessitates the application not only of pre- and post-operation analysis, but also during the process of switching. This highly challenging in situ characterization also requires the aforementioned techniques while simultaneously applying an electrical bias. Through this review we aim to give an overview of the possibilities and challenges as well as an outlook onto future developments in the field of nanoscopic characterization of memristive devices.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.78-81
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• 2004

사회가 고도의 디지털 정보화 시대로 급속히 발전함에 따라 영상 및 음성 데이터의 획득, 전송, 저장을 위한 멀티미디어 통신 서비스가 상용화 되어가고 있다. 그러나 여전히 데이터를 디지털화하거나 전송하는 과정에서 여러 가지 원인에 의해 노이즈가 발생하고 있으며, 이러한 노이즈를 제거하기 위한 연구는 지금까지 계속되고 있다. 그리고 영상에 중첩된 AWGN을 제거하기 위한 기존의 방법으로는 평균 필터가 대표적이다. 그러나 이러한 평균 필터는 저주파 특성이 우수하지만 영상에서 고주파 특성의 열화를 가져온다. 따라서 본 논문에서는 기존의 평균 필터에 방향성 정보를 추가하여 노이즈를 제거함과 동시에 고주파 특성의 열화가 감소되도록 하였다.

• 한국군사과학기술학회지
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• 제15권6호
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• pp.786-801
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• 2012

The most essential ROC(requirement operational capability) in order to assure the effectiveness of the C4I Systems in NCW Environments is the seamless and stable interoperability between systems. The U.S. Armed Forces that perceived the importance of interoperability, prepared the framework to apply from the proposal of requirement to every step of acquisition process. The Korea Joint Chiefs of Staff is also developing a similar system in order to assure the interoperability between command control(C4I) systems. In the paper, we specify the needs of standardization of test systems and international trends on the technology, and propose an interoperability test & evaluation system based on a standardization conformity method to improve the interoperability test & evaluation for the C4I systems in NCW environments. Finally we show an example of the implementation of the test system and its application to C4I systems to verify the proposed test system.

• 한국산학기술학회논문지
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• 제10권7호
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• pp.1702-1710
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• 2009

본 논문은 rework 발생확률을 고려하는 병렬기계 스케줄링 문제를 위해 문제공간기반 탐색 알고리즘을 제안한다. 각 기계와 작업유형별로 rework 발생확률이 존재하며 이것은 자동화된 공정에서 과거데이터로부터 산출가능하다. 스케줄링 문제의 데이터 벡터 (가공시간, 납기, 셋업시간, rework확률)를 교란시킴으로써 이웃해를 생성하고 이로부터 도출된 해는 EDDR이라는 효과적인 휴리스틱을 이용하여 평가한다. 제안된 알고리즘은 납기지연의 최대값과 rewok 발생 작업수로 평가함으로써 제품의 품질과 납기수준을 동시에 고려할 수 있도록 한다.

• 한국도로학회논문집
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• 제15권5호
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• pp.177-185
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• 2013

PURPOSES : This study attempts to design and establish the road surface condition detection system by using the image processing that is expected to help implement the low-cost and high-efficiency road information detection system by examining technology trends in the field of road surface condition information detection and related case studies. METHODS : Adapted visual information collecting method(setting a stereo camera outside of the vehicle) and visual information algorithm(transform a Wavelet Transform, using the K-means clustering) Experiments and Analysis on Real-road, just as four states(Dry, Wet, Snow, Ice). RESULTS : Test results showed that detection rate of 95% or more was found under the wet road surface, and the detection rate of 85% or more in snowy road surface. However, the low detection rate of 30% was found under the icy road surface. CONCLUSIONS : As a method to improve the detection rate of the mobile road surface condition information detection system developed in this study, more accurate phase analysis in the image processing process was needed. If periodic synchronization through automatic settings of the camera according to weather or ambient light was not made at the time of image acquisition, a significant change in the values of polarization coefficients occurs.

• 한국국방경영분석학회지
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• 제28권2호
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• pp.85-94
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• 2002

Calculation of proper expenses on acquisition and purchasing defense product is matter of survival and weighing the morality for both defense industry and the national facilities. With this reason, both parties have been a big job to estimate the resonable cost. The cost are composed of many subordinated parts such as material cost, labor cost, and so on. In the compositions of that cost, the most important part in between companies and the government throughout the whole calculating process is to define the proper labor cost. When both parties calculate imported articles or overhead expenses, they can easily calculate and confirm by documented evidences or related materials. In other hand, the labor cost, which can be seen as two absolutely different numbers and opinions can be created, depends on analyzer's point of view. These interpretation and judgment of data cannot avoid analyzer's intention. In accordance with the above matters, defining the reasonable labor cost will be the top priority in order to analyze the proper expenses. This study will provide a method of proper labor cost estimation before starting the actual manufacturing to calculate the rational labor cost.

• Journal of Mechanical Science and Technology
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• 제20권6호
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• pp.864-873
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• 2006

As fuel cells approach commercialization, hydrogen production becomes a critical step in the overall energy conversion pathway. Reforming is a process that produces a hydrogen-rich gas from hydrocarbon fuels. Hydrogen production via autothermal reforming (ATR) is particularly attractive for applications that demand a quick start-up and response time in a compact size. However, further research is required to optimize the performance of autothermal reformers and accurate models of reactor performance must be developed and validated. The design includes the requirement of accommodating a wide range of experimental set ups. Factors considered in the design of the reformer are capability to use multiple fuels, ability to vary stoichiometry, precise temperature and pressure control, implementation of enhancement methods, capability to implement variable catalyst positions and catalyst arrangement, ability to monitor and change reactant mixing, and proper implementation of data acquisition. A model of the system was first developed in order to calculate flowrates, heating, space velocity, and other important parameters needed to select the hardware that comprises the reformer. Predicted performance will be compared to actual data once the reformer construction is completed. This comparison will quantify the accuracy of the model and should point to areas where further model development is required. The end result will be a research tool that allows engineers to optimize hydrogen production via autothermal reformation.

• 한국항행학회논문지
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• 제24권4호
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• pp.285-290
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• 2020

본 논문에서는 텔레메트리 시스템에 적용하기 위한 PLL 기반의 시각동기 알고리즘을 제시하고 FPGA 로직을 구현하였다. 텔레메트리 시스템에서 대형 비행체의 경우 각각의 분산 획득 장치들을 통해 상태정보를 계측하여 실시간으로 비행 상태를 분석해야하므로 정밀도 향상을 위한 장치 및 시스템 간의 시각 동기의 중요성이 커지고 있다. 이 때문에 시각동기 기법으로 타 시각동기 방법보다 복잡도가 적고, 동기를 위한 추가적인 메시지 전송을 최소화하여 데이터 처리에 적은 시간이 소요되는 PLL 기반의 시각동기 알고리즘을 제안하였다. 타당성을 확인하기 위해 python 시뮬레이션을 수행하였으며 최종적으로 FPGA 내에 VHDL 로직을 구현하여 시각 동기 성능을 확인하였다.

• 한국컴퓨터정보학회논문지
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• 제11권4호
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• pp.165-174
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• 2006

상황 인식 서비스는 상황 획득 및 추론 과정 등의 기능을 지원함으로써, 상황 인식 서비스의 구현을 쉽게 하는 연구들이 진행되어 왔다. 그러나. 이들 연구에서는 유비쿼터스 컴퓨팅 환경에서 필수적으로 지원되어야 하는 사용자 및 서비스의 이동성을 효과적으로 지원하지 못하고 있다. 따라서, 본 논문에서는 서비스의 이동성을 효과적으로 지원하기 위해서 서비스간의 상호 작용을 위한 서비스 검색 및 조합, 서비스 이동성을 지원하는 동적 상황 인식 서비스 모델을 제안하고 이 모델을 기반으로 상황 인식 미들웨어를 설계 구현한다. 또한 설계하는 미들웨어는 OSGi 프레임워크 위에서 구현함으로써 UPnP. Jini 등의 표준 인터페이스 기술을 이용해서 다양한 가전과 센서 등의 외부 기기들과 연동이 가능하다.