• Journal of Advanced Marine Engineering and Technology
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• 제21권4호
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• pp.404-413
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• 1997

Direct-drive robots are suitable to position and force control with high accuracy, but it is difficult to design a controller which gives satisfactory perfonnance because of the system's nonlinearity and link-interactions. This paper is concerned with the force control of direct-drive robots. The pro¬posed algorithm consists of feedback controllers and a neural network. Mter the completion of learning, the outputs of feedback controllers are nearly equal to zero, and the neural network con¬troller plays an important role in the control system. Therefore, the optimum adjustment of parameters of feedback controllers is unnecessary. In other words, the proposed algorithm does not need any knowledge of the controlled system in advance. The effectiveness of the proposed algo¬rithm is demonstrated by the experiment on the force control of a parallelogram link-type direct¬drive robot.

• 소성∙가공
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• 제4권3호
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• pp.233-244
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• 1995

Rolling force in the direct rolling(or twin-roll strip continuous casting) process fo semi-solid material has been computed using rigid-viscoplastic finite element method. Temperature distributions for calculations of rolling force and roll deformation are obtained from thermofluid analysis. Three dimensional roll deformation analysis has also been performed by using commercial package ANSYS. From the results, behavior of metal flow, rolling force and roll deformation have been investigated according to the process conditions of semi-solid direct rolling.

• Journal of Power Electronics
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• 제6권2호
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• pp.146-162
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• 2006

This paper deals with the analysis, design and implementation of an AC-DC Zeta converter in discontinuous current mode (DCM) of operation used for power quality improvement at AC mains in direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drives. The designed Zeta converter feeds a direct torque controlled PMSM drive system. Modeling and simulation is carried out in a standard PSIM software environment. Test results are obtained on the developed prototype Zeta converter using DSP ADMC401. The results obtained demonstrate the effectiveness of the Zeta converter in improving power quality at AC mains in the PMSM drive system.

• 한국정밀공학회지
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• 제26권5호
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• pp.79-86
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• 2009

Recently PMSM(Permanent magnet synchronous motor) are used for the various direct drive applications such as index table, telescope system and so on. Because the position/speed control performance of direct drive PMSM is directly affected by the torque ripple, there are lots of studies to reduce the cogging torque in the motor design stage. In order to verify the motor design, the reliable cogging torque measurement system is essentially required. The measured motor must be rotated in the constant speed under 1deg/sec so that the cogging torque profile is measured correctly. In this study, the cogging torque measurement system which uses the direct drive PMSM and the speed controller to rotate the measured motor in 0.1rpm(0.6deg/sec) has been developed. Simulink/xPC target was used for the controller and data acquisition system. Based on PI controller, DOB and AFC have been applied to eliminate the low frequency disturbances and the periodic speed ripple. The experimental results show the good performance of the speed regulation for the reference speed 0.1rpm and the reliable profile of the measured cogging torque by the developed speed controller.

• 복식
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• 제66권4호
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• pp.111-127
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• 2016

The study aims to examine the forms of 'image expression' and utilization of model poses in fashion photos, and to delve into the characteristics and the intents that make certain model poses effective in expressing an image. The study used the fashion photos in the fashion magazine, Vogue, to analyze the different model poses used to express different images. The results are as follows. First, image expression forms in fashion photos were categorized into 'direct product suggestion expression form', 'sensual image expression form', 'sexual image expression form', 'story telling expression form', 'everyday situation expression form', and 'fantastic image expression form'. The different utilization types of model poses were categorized into 'type utilizing intangible elements', 'type utilizing complicated elements', 'type utilizing living organisms', 'type utilizing props', 'type utilizing clothes', 'type utilizing location', 'type utilizing accessories', and 'type utilizing products'. Second, the most common expression form for fashion photos used in advertisements was the 'direct product suggestion expression form', which was followed by the sensual image expression form. The most popular form used in the editorial fashion photos was the direct suggestion product expression form, which was followed by the story telling expression form. Third, the most common model pose type for direct product suggestion form was the 'type utilizing product'. Fourth, 'direct product suggestion expression form' was mostly used in editorial fashion photos. The most common utilization types of model poses were 'type utilizing clothes', 'type utilizing props', and 'type utilizing place'.

• 구강회복응용과학지
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• 제32권3호
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• pp.246-254
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• 2016

Direct metal laser sintering (DMLS) 방식은 3D 프린팅 중 한 방식으로, 재료를 쌓아가면서 레이저를 이용하여 선택적으로 sintering하는 방식이다. 이는 주조 방식에서 문제되는 결손과 뒤틀림을 방지할 수 있으며 절삭 가공 방식으로 제작하기 어려운 복잡한 구조물을 제작할 수 있다. 본 증례들은 DMLS 방식을 이용하여 지대치 간 길이가 긴 고정성 보철물, 포스트 등 다양한 고정성 보철물을 제작하여 수복하였고, 주기적인 관찰 결과 심미적, 기능적으로 만족할만한 결과를 얻었기에 이를 보고하는 바이다.

• 한국전산구조공학회논문집
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• 제12권3호
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• pp.427-435
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• 1999

형상 최적설계에서 절점의 재배치 및 형상 민감도 계산은 많은 노력이 필요하다. 본 연구에서는 구조물의 형상을 Bezier 곡선을 이용하여 표현하고, 민감도 계산을 위하여 개선된 직접미분법을 이용한다. 그리고, 절점의 재배치에는 변위장을 수정한 속도장을 이용한다. 또한, 본 연구에서는 자중을 고려한 외팔보와 3차원 저널베어링을 수치예제로 선택하여 본 연구의 기법들을 적용한 형상 최적설계를 해석한다.

• Nuclear Engineering and Technology
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• 제38권2호
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• pp.109-118
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• 2006

Various indirect power cycle options for a helium cooled gas cooled fast reactor (GFR) with particular focus on a supercritical $CO_2(SCO_2)$ indirect cycle are investigated as an alternative to a helium cooled direct cycle GFR. The balance of plant (BOP) options include helium-nitrogen Brayton cycle, supercritical water Rankine cycle, and $SCO_2$ recompression Brayton power cycle in three versions: (1) basic design with turbine inlet temperature of $550^{\circ}C$, (2) advanced design with turbine inlet temperature of $650^{\circ}C$ and (3) advanced design with the same turbine inlet temperature and reduced compressor inlet temperature. The indirect $SCO_2$ recompression cycle is found attractive since in addition to easier BOP maintenance it allows significant reduction of core outlet temperature, making design of the primary system easier while achieving very attractive efficiencies comparable to or slightly lower than, the efficiency of the reference GFR direct cycle design. In addition, the indirect cycle arrangement allows significant reduction of the GFR &proximate-containment& and the BOP for the $SCO_2$ cycle is very compact. Both these factors will lead to reduced capital cost.

• 한국실내디자인학회논문집
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• 제22권1호
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• pp.299-306
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• 2013

While artists and architects both recognize the importance of well-designed exhibition spaces, they have rarely shared, through direct and open communication, their thoughts on what constitutes an ideal architectural context for art. Remy Zaugg's text offers a rare and valuable insight on artists' conception of an ideal space for art, and his words and diagrams have directly influenced some of the successful architectural projects for art in the recent past. By analyzing the original content of Zaugg's writings, and highlighting Zaugg's key design elements from three sample projects, all of which mention Zaugg's text as a direct reference, we can compile a list of core design elements for constructing an ideal space for art. Three museums closely incorporated all but two of Zaugg's seven core planning elements, and the remaining two recommendations on the luminous ceiling and gallery distribuition were more subjectively interpreted. These deviant components in turn become unique features to each project, suggesting proper areas of intervention for architects as authors.

• 한국의류산업학회지
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• 제12권5호
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• pp.650-656
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• 2010

To present a 6-piece baseball cap pattern with good wearing sensation and with good reflection of head shape, this study conducted direct measurement using martin's anthropometer and indirect measurement using surgical tape among women of 20 to 24 years old. For a crown, correlation analysis was carried out between direct measurements and surface shell measurements of each section on the head to set main items for prototype design, along with regression analysis to complete design formula; for a cap pattern, draping design was used on the finished crown to compete cap pattern design formula. The results showed that main measurement items to design a baseball cap included head circumstance and bitragion arc for a crown and the cephalic index for a cap. For the crown pattern reflecting the shape of the head, 6 pieces were designed with different sizes and types of front (F), side (S), and back (B) patterns; hemline was also designed diagonally and completed by reflecting the curve of the head.