• Journal of Digital Contents Society
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• v.1 no.1
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• pp.13-22
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• 2000

In this paper, it is designed and implemented the management system to monitor and control PCs running on MS Windows or NT and define some MIBs using SNMP. The proposed system has controlling functions to control the status of PC and monitoring functions to have real-time monitoring and control processes. The controlling system supports update and setting of the configuration information of managed systems and backup/restore the information when it happens to be some faults. The monitoring system has some functions such as monitoring the processes of the PC, controlling the process on PC, and invoking a new job. This paper proposes a way of enhancing the performance of monitoring capabilities by screen partitioning and analysis techniques.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.8
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• pp.1422-1430
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• 2016

Researches for oceans are limited to military purpose such as underwater sound detection and tracking system. Underwater acoustic communications with low-probability-of-interception (LPI) covert characteristics were received much attention recently. Covert communications are conducted at a low received signal-to-noise ratio to prevent interception or detection by an eavesdropper. This paper proposed optimal covert communication model based on direct sequence spread spectrum for underwater environments. Spread spectrum signals may be used for data transmission on underwater acoustic channels to achieve reliable transmission by suppressing the detrimental effect of interference and self-interference due to jamming and multipath propagation. The characteristics of the underwater acoustic channel present special problems in the design of covert communication systems. To improve performance and probability of interception, we applied BCJR(Bahl, Cocke, Jelinek, Raviv) decoding method and the direct sequence spread spectrum technology in low SNR. Also, we compared the performance between conventional model and proposed model based on turbo equalization by simulation and lake experiment.

• Journal of Broadcast Engineering
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• v.16 no.5
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• pp.883-893
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• 2011

In this paper, we propose a novel focus measure that determines in-focus and out-of-focus region in an image. In addition, we achieved extended depth of field by blending the acquired image and Wiener filtered image using a decision map based on the designed focus measure. Since conventional focus measures are based on the amount of high frequency components in an acquired image, the measures may not be accurate if there exist high frequency components in out-of-focused region. To overcome the problem, we designed the novel focus measure based on effective band pass filtering. In simulations and experiments, the proposed method showed better performance than existing methods.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.636-638
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• 2003

현재 장애인의 삶의 질을 향상시키고자 노력의 하나로서 장애인을 위한 다양한 정보통신기기들이 개발되고 있다. 그 중에서 지체장애인을 위한 가상자판(virtual keyboard)은 눈동자의 방향에 따라 글자를 입력하는 장치이다. 현재 만들어지는 가상자판은 눈의 피로를 고려하지 않아서 실생활에서 사용하기에 어려운 점이 많다. 본 논문은 이러한 문제점을 해결하기 위하여 유전 알고리즘(genetic algorithms)을 이용하여 가상자판의 배열을 최적화하는 방법을 제시한다. 실험 결과는 피로도, 이동거리, 글쇠 누르는 횟수에 있어서 전반적으로 좋은 성능을 보이고 있다.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.697-700
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• 2000

Fatigue damage to reinforced concrete bridge decks have been found in many bridges. Failure mode of most reinforced concrete decks is caused by local punching shear rather than flexural moment due to cumulated damage. In this study, mechanical degradation of unstrengthened and strengthened bridge deck specimens is experimentally investigated. The unstrengthened deck specimens were damaged under the pulsating loading condition. After the test, deteriorated deck specimens were strengthened with Carbon Fiber Sheet, then loaded to observe the improvement of the fatigue behavior. It is shown that fatigue damaged specimens are similar to real bridge rather than static damaged specimens.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.94-97
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• 2006

This paper reports fatigue test results of 1/3 scaled PSC slab models using moving wheel loading machine. The purpose of the test is to improve the fatigue formulas by comparing the existing formulas with the test results. Based on the result, improved fatigue formula is proposed for the PSC slab.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.348-348
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• 2010

신 차종의 개발 시, 기존 차량 모델을 사용하여 재 설계하는 방식에 의해 전례 없이 빠르게 차량 개발을 수행하고 있다. 또한 대부분의 이들 후속 차량은 공통 플렛폼 상에 설계되고 있으며, 일반적으로 충격, 구조 건전성, 생산 타당성 검토 등의 컴퓨터 시뮬레이션은 개발 프로세서 초기 단계에서 행하여 지고 있으나. NVH 엔지니어링은 차량 개발 프로세스의 매우 중요한 과정으로 되어 있음에도 불구하고, 실내 소음, 진동 승차감, 피로 수명 예측 등은 사용되는 해석 모델의 크기 및 복잡성으로 인하여 이들 성능 특성 평가 및 최적화는 아직 도전 과제이며, 본 논문에서는 몇몇 선진 OEM에서 수행되고 있는 NVH 개발 프로세스와 이를 가능케 하는 기법을 소개한다.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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• v.27 no.3
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• pp.44-50
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• 2016

W-대역 잡음온도 표준 확립에 필요한 잡음전력 수신기인 라디오미터를 제작하고, 성능을 평가하였다. 제작된 라디오미터를 사용하여 기준 상온 및 저온잡음원, 그리고 피측정잡음원의 잡음전력을 각각 측정하고, 라디오미터 식을 사용하여 피측정잡음원의 잡음온도를 구하였다. 결과에 대한 측정불확도를 평가하고, 국외 측정표준기관인 영국 NPL의 측정결과와 비교함으로써 측정의 유효성을 검증하였다. 확립된 W-대역 잡음온도 측정표준을 국내 산학연에 보급함으로써 자동차, 항공, 우주, 국방, 보안 등 다양한 분야의 잡음측정에 있어서 측정의 신뢰성을 높이는데 기여하게 될 것이다.

• Journal of the KSME
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• v.19 no.2
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• pp.119-123
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• 1979

높은 탄성계수와 인장응력, 우수한 피로 및 충격저항력, 그리고 높은 진동 흡수력을 가지면서도 가벼운 보강된 복합재료는 로켓트나 미사일 부분에서 뿐만 아니라 다방면의 산업분야에 응용될 수 있다. (다음, 호에 타 응용분야를 소개할 예정임), 경량의 고강도 복합재료야인 High-Performance을 만들기 위해서는 첫째 우수한 성능을 발견할 수 있는 기계의 제조, 둘째 기계 상호간을 강력하게 결합시킬 수 있는 매트릭스 재료(Matrix Material)의 선정, 셋째, 기계와 매트릭스 재료의 결합을 강화시키기 위한 기계의 표면처리, 넷째 원하는 모양으로 만드는 성 형(Forming and Shaping) 기술의 개발이 필수적이다.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.602-608
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• 2021

Recently, research and development has been conducted to impart high performance and functionality to concrete materials by mixing various reinforcing materials into the matrix. Ductile fiber reinforced concrete using a large amount of fibers shows a distributed multiple cracking behavior, and various studies are being conducted on this material. However, research is focused on static behavioral analysis but studies on cyclic behaviors are not sufficient. In this study, beams were made of ductile fiber reinforced concrete with various fiber contents, and static and fatigue flexural tests were performed. As a result, the effect of fiber content on the flexural behavior was analyzed. Also, the applied load level and fatigue life relationship of ductile fiber reinforced concrete was proposed. Concrete with high ductile property could be achieved with a fiber content of 2%. When 0.5% fiber was more added, the maximum flexural strength was similar, but the flexural toughness is nearly doubled. On the other hand, there was no significant difference in the fatigue life of these two mixtures.