• Structural Monitoring and Maintenance
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• 제6권4호
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• pp.291-315
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• 2019

Fatigue cracks are inevitable in circumstances in which the cyclic loading exists. Therefore, many of mechanical components are in a risk of being in exposure to fatigue cracks. On the other hand, renewing the facilities or infrastructures is not always possible. Therefore, retrofitting the structures by means of the available methods, such as crack arrest methods is logical and in some cases inevitable. In this regard, this paper considers three popular crack arrest methods (e.g., drilling stop-hole, steel welded patch, and carbon fiber reinforced (CFRP) patch), which have been compared by using extended finite element method (XFEM). In addition, effects in terms of the width and thickness of patches and the configuration of drilling stop holes have been evaluated. Test results indicated that among the considered methods, CFRP patches were the most effective means for arresting cracks. Besides, in the case of arresting by means of drilling stop holes, drilling two holes next to the crack-tip was more effective than blunting the crack-tip by drilling one hole. In other words, the results indicated that the use of symmetric welded metal patches could lead to a 21% increase in fatigue life, as compared to symmetric stop holes. Symmetric CFRP patches enhanced the fatigue life of cracked specimen up to 77%, as compared to drilling symmetric stop holes. In addition, in all cases, symmetric configurations were far better than asymmetric ones.

• 음성과학
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• 제3권
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• pp.109-117
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• 1998

This paper tests whether the VOT (Voice Onset Time) contributes to the perception of tense and plain stops in Korean in the initial position. Previous studies have yielded opposite results regarding the role of the VOT in the distinction of these two stop categories. One the one hand, Lisker and Abramson (1964), Kim (1965), and Han and Weitzman (1970) suggest that the Korean plain and tense stops exhibit overlapping values of VOT and thus that, unlike many other languages, the VOT fails to serve as a cue to separate these stop categories. On the other hand, Silva (1991, 1992), and Lee (1991, 1994) use similar methods, but find that the VOT serve as the cue. In this study, the differences in the acoustic measurement with respect to the VOT of Korean plain and tense stops in initial prevocalic position will be tested preceptually, in seeking to determine whether these acoustic differences are used by listeners to distinguish these two stop types.

• 한국융합학회논문지
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• 제9권6호
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• pp.17-23
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• 2018

본 논문에서는 기존의 콘텐츠 관리 시스템의 한계를 극복하고자, 하나의 콘텐츠 관리 시스템의 트랜스코딩 엔진을 이용하여 IPTV, WEB, Mobile, Smart Device 등에 서비스할 수 있는 콘텐츠 관리 시스템(CMS)을 개발한 사례를 소개한다. 개발된 CMS는 하나의 콘텐츠를 동시에 여러 개의 콘텐츠로 트랜스코딩하여 각 각의 디바이스에 자동으로 인지하여 최상의 콘텐츠를 서비스함으로써 CMS 추가 도입에 대한 부담감을 줄이고, 관리자의 개입을 최소화시킴으로써 효율적인 콘텐츠 관리를 할 수 있도록 설계 되었다. 스튜디오에서 제작된 콘텐츠에 대한 자동화시스템과 모바일에서 촬영된 영상에 대한 자동관리 기능으로 활용에 중점을 두고 있으며, 추후 콘텐츠 생산에 대한 기능을 추가함으로써 콘텐츠에 대한 One-Stop Service를 할 수 있도록 발전시켜갈 계획이다.

• 음성과학
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• 제14권1호
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• pp.105-119
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• 2007

The purpose of this study is to examine Korean students' production and perception of word-final stop voicing in light of their overseas experience. Subjects were English native speakers, Korean university students with residence experience in America, Korean university students without residence experience in America, and Korean elementary school students. They participated in both production and perception tests. Results showed that the students' production and perception with residence experience in America appeared quite similar to those of the English native speakers. In the production tests, we noticed somewhat different results in temporal and frequency features. The one-year residence in America had some influence on their frequency features, but not the temporal features in the word final stop production. That difference could be seen in the perception tests, too. We could not find any difference in the identification test of the final release environment between the Korean university students who had studied abroad and those who didn't. Rather the difference could be found in the cue influence test in both the final release and non-release environments.

• ETRI Journal
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• 제32권5호
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• pp.827-830
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• 2010

For an adaptive cruise control (ACC) stop-and-go system in automotive applications, three radar sensors are needed because two 24 GHz short range radars are used for object detection in an adjacent lane, and one 77 GHz long-range radar is used for object detection in the center lane. In this letter, we propose a single sensor-based 24 GHz radar with a detection capability of up to 150 m and ${\pm}30^{\circ}$ for an ACC stop-and-go system. The developed radar is highly integrated with a high gain patch antenna, four channel receivers with GaAs RF ICs, and back-end processing board with subspace based digital beam forming algorithm.

• 전기학회논문지P
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• 제63권2호
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• pp.113-118
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• 2014

Tidal power is one of new and renewable energy sources. Tidal power is generated by using the gap in the water level between the water outside and inside the embankment. All tidal power plant in Korea were being operated by import of turn-key from abroad. The know-how and technology which are the most important to build predictive control system has become increasingly difficult to obtain from advanced countries because most of them avoid to transfer, which the domestic development of the control system is needed. In this paper, a study on start stop system at water turbine-generator for tidal power plant at the beginning of development was presented. For improvement the efficiency and develope of core technology of the start stop system, the technique and characteristics of tidal power, modeling, maximum generation calculation method, and optimal control of joint control system in Sihwa tidal power plant were studied.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1999년도 춘계학술대회 논문집
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• pp.251-258
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• 1999

This paper is mainly concerned with the development of the ATO(Automatic Train Operation) profile on precision stop controller. The ATO system is used for automatic or driverless operation of a train. In this paper, the algorithm for ATO controller is presented and three speed profiles on precision stop controller are compared. One profile is based on the maximum jerk control, another on the constant control input, and the third on the optimal control for the minimum energy consumption. These profiles are simulated and analyzed in view of the stop time, control input, jerk, propulsion and braking.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.583-586
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• 2000

The non-selective method by polishing after grinding was used widely to thinning of SDB SOI structures. This method was very difficult to thickness control of thin film, and it was dependent on equipments. However electrochemical etch-stop, one of the selective methods, was able to accurately thickness control and etch equipment was very simple. Therefore, this paper described with the effect of leakage current and electrodes on electrochemical etch-stop. Consequentially, PP(passivation potential) was changed according to the kinds of contact and contact sizes, but OCP(open current potential) was not change with range of -1.5~-1.3V

• 보건세계
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• 제59권3호
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• pp.20-21
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• 2012

• Social Workers
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• 11호통권43호
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• pp.52-54
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• 2005