• 전자공학회논문지A
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• 제32A권12호
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• pp.198-208
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• 1995

BiCMOS circuit consist of CMOS part which constructs logic function, and bipolar part which drives output load. Test to detect stuck-open faults in BiCMOS circuit is important, since these faults do sequential behavior and are represented as transition faults. In this paper, proposes a method for efficiently detecting transistor stuck-open faults in BiCMOS circuit by transforming them into slow-to=rise transition and slow-to-fall transition. In proposed method, BiCMOS circuit is transformed into equivalent gate-level circuit by dividing it into pull-up part which make output 1, and pull-down part which make output 0. Stuck-open faults in transistor are modelled as transition fault in input line of gate level circuit which is transformed from given circuit. Faults are detceted by using pull-up part gate level circuit when expected value is '01', or using pull-down part gate level circuit when expected value is '10'. By this method, transistor stuck-open faults in BiCMOS circuit are easily detected using conventional gate level test generation algorithm for transition fault.

• 지적과 국토정보
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• 제47권2호
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• pp.185-199
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• 2017

본 연구는 예측하기 어려운 미래의 다양한 수요를 수용하기 위하여 재조합방법을 통한 공간정보제품 제작방법을 제안한다. 현재의 측량중심의 공간정보제품의 생산방안은 특정 지도제품 중심의 Top-down방식이므로 공간정보의 활용 확산 관점에서는 한계점을 가지고 있다. 이는 불특정 다수를 위한 공간정보의 활용성 관점보다는 모두를 위한 지도라는 관점에서 다양한 수요를 만족시키기에는 한계가 있다. 이런 한계점을 해결을 위해 사용자 맞춤형의 Bottom-up방식 공간정보 생산과 재조합을 통한 공간정보 제품 제작이 요구되고 있다. 이를 위해 본 논문은 기존의 Top-down 방식의 결과인 수치지도와 재조합을 통한 공간정보제품의 제작에 대한 이론적 고찰과 비교를 통해 보완 방안을 제안하였다. 이는 공간정보를 기초속성을 가지는 형태와 관계된 속성정보를 가지는 데이터로 재분류하고 각 데이터에 관계성 및 관리에 관한 속성을 부여하는 방안이다. 이 방법의 실효성 증명을 위해 기존 수요의 만족 가능성과 미래 수요의 대응 가능성을 중심으로 적용사례를 도출하였다, 그리고 기존의 국가기본도, 주제도, 향후 수요 예측 제품의 해당 대표제품을 제작하여 확인하였다.

• 한국세라믹학회지
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• 제39권9호
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• pp.835-839
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• 2002

Micro-Pulling Down(${\mu}$-PD)법을 이용하여 직경 1 mm, 길이 30∼35 mm의 $Er_2O_3$와 MgO가 첨가된 화학양론조성 $LiNbO_3$단결정을 성장하였다. 성장된 결정의 $Er_2O_3$와 MgO 첨가에 따른 up-conversion 특성의 변화 및 MgO 첨가량이 광손상에 미치는 영향을 관찰하기 위해 투과율을 측정하였다. 또한 $LiNbO_3$ 단결정 내의 결함유무를 광학현미경을 이용하여 관찰하였고, Electron Probe Micro Analysis(EPMA)를 이용하여 결정 내에 $Er_2O_3$와 MgO가 균일하게 분포되어있음을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.273-274
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• 2021

This paper proposes a process to calculate the amount of construction and demolition (C&D) of underground vertical extension methods through considering the characteristics of used construction and demolished materials. The underground vertical extension methods analyzed in this paper were the bottom-up, normal top-down, and top-down methods with multi-post downward (MPD). In order to check the applicability of the proposed process, 24 illustrative examples were generated. The amount of C&D waste of the illustrative examples were calculated and compared. As the results, the top-down method with MPD was the most efficient method to reduce the amount of C&D waste.

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.211-221
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• 1998

It is becoming apparent that stereo matching algorithms need much information from high level cognitive processes. Otherwise, conventional algorithms based on bottom-up control alone are susceptible to local minima. We introduce a system that consists of two levels. A lower level, using a usual matching method, is based upon the local neighborhood and a second level, that can integrate the partial information, is aimed at contextual matching. Conceptually, the introduction of bottom-up and top-down feedback loop to the usual matching algorithm improves the overall performance. For this purpose, we model the image attributes using a Markov random field (MRF) and thereupon derive a maximum a posteriori (MAP) estimate. The energy equation, corresponding to the estimate, efficiently represents the natural constraints such as occlusion and the partial informations from the other levels. In addition to recognition, we derive a training method that can determine the system informations from the other levels. In addition to recognition, we derive a training method that can determine the system parameters automatically. As an experiment, we test the algorithms using random dot stereograms (RDS) as well as natural scenes. It is proven that the overall recognition error is drastically reduced by the introduction of contextual matching.

• 한국정밀공학회지
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• 제20권10호
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• pp.31-40
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• 2003

In this paper, optimal cutting condition to minimize the form error in side wall machining with a flat end mill is studied. Cutting forces and tool deflection are calculated considering surface shape generated by the previous cutting such as roughing. Using the form error prediction method from tool deflection, optimal cutting condition considering form accuracy is investigated. Also, the effects of tool teeth number, tool geometry and cutting conditions on form error are analyzed. The characteristics and the difference of generated surface shape in up and down milling are discussed and over-cut free condition in up milling is presented. Form error reduction method through successive up and down milling is also suggested. The effectiveness and usefulness of the presented method are verified from a series of cutting experiments under various cutting conditions. It is confirmed that form error prediction from tool deflection in side wall machining can be used in optimal cutting condition selection and real time surface error simulation for CAD/CAM systems. This study also contributes to cutting process optimization for the improvement of form accuracy especially in precision die and mold manufacturing.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 추계학술대회 논문집
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• pp.293-298
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• 2001

2span continuous Prestressed concrete girder railway bridges, span length 21m, 25m, 30m, 35m, that down-up method is applied and that designed to satisfy service load in accordance with design criteria of railway bridge can be dropped in their hight compared with existing simply supported prestressed concrete girder railway bridges. Continuous bridges result in guaranteeing safety against bending behavior by loading the practical railway moving load with each velocity. But the natural frequency of span length 21m is estimated not to satisfy recommended limitation of UIC 776-1R..

• 한국정밀공학회지
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• 제15권6호
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• pp.58-63
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• 1998

There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

• Journal of Power Electronics
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• 제18권1호
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• pp.137-146
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• 2018

This paper describes a single pulse-width modulation control strategy using the Single Pulse-Width Modulation (SPWM) method with a soft-switching technique for a wide range of output voltages from a bidirectional Dual-Active Bridge (DAB) converter. This method selects two typical inductor current waveforms for soft-switching, and proposes a rule that makes it possible to achieve soft-switching without any compensation algorithm from the waveforms. In addition, both the step-up and step-down conditions are analyzed. This paper verifies that the leakage inductance is independent from the rule, which makes it easier to apply in DAB converters. An integrated algorithm, which includes step-up and step-down techniques, is proposed. The results of experiments conducted on a 50-kW prototype are presented. The system efficiency is experimentally verified to be from 85.6% to 97.5% over the entire range.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 심포지엄 논문집 정보 및 제어부문
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• pp.108-110
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• 2004

Automatic license plate recognition (LPR) is one of the critical techniques of the intelligent transportation system (ITS), in which license plate location plays an important role. In this paper, through surveying the international existing techniques, a new method for locating license plate is proposed: utilize row scan method to locate up and down boundary of the plate; and based on the location of up and down boundary, take advantage of the feature of plate area to locate left and right boundary of the plate. The tests of using the proposed algorithms have been conducted. The experimental results show that the proposed approaches are reasonable and accurate.