• Title/Summary/Keyword: Direct Modification

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A direct modification method for strains due to non-conforming modes

  • Choi, Chang-Koon;Chung, Keun-Young;Lee, Tae-Yeol
    • Structural Engineering and Mechanics
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    • v.11 no.3
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    • pp.325-340
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    • 2001
  • This paper addresses an efficient modification method that eliminates the undesirable effects of strains due to various non-conforming modes so that the non-conforming element can pass the patch test unconditionally. The scheme is incorporated in the element formulation to establish new types of non-conforming hexahedral elements designated as NHx and NVHx for the regular element and variable node element, respectively. Non-conforming displacement modes are selectively added to the ordinary (conforming) element displacement assumptions to improve the bending behavior of the distorted solid element. To verify the validation of proposed direct modification method and the improvement of element behavior, several numerical tests are carried out. Test results show that the proposed method is effective and its applications to non-conforming solid elements guarantee for the element to pass the patch test.

A study on the roboust discrete adaptive control algorithm (견고한 이산치 적응제어 알고리즘에 관한 연구)

  • 천희영;박귀태;박귀태;이종렬
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.242-245
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    • 1988
  • This paper presents a robust discrete MRAC with the discrete e/sub 1/ -modification. Discrete e/sub 1/ -modification is proposed by extending the Narendra's e/sub 1/ -modification to the discrete version. In this case the adaptive controller was reformed by Lyapunov's direct metbod. And the improved robustness by using this algorithm was showed by sector theory.

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Self-Assembly Modification of Perfluorosulfonic Acid Membranes for the Application to Direct Methanol Fuel Cells

  • Moon, Go-Young;Rhim, Ji-Won
    • Macromolecular Research
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    • v.16 no.6
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    • pp.524-531
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    • 2008
  • The mitigation or elimination of methanol crossover for perfluorosulfonic acid fuel cell membranes has been investigated extensively for direct methanol fuel cell applications with the aim of increasing the electrochemical performance and enhancing the utilization rate of methanol. Self-assembly modifications by applying an oppositely charged polyelectrolyte to Nafion membranes were attempted in order to block or reduce methanol crossover while maintaining the other advantageous properties of Nafion membranes. It was reported that anionic polyallylamine hydrochloride (PAH) was the most efficient polyelectrolyte in reducing methanol crossover, and considerable cell performance was obtained even at a methanol feed concentration of 10 M.

Design of 3D Stereoscopic Electronic Book Authoring Tool Based on DirectX (DirectX기반 3차원 입체 eBook 영상 및 이미지 저작 도구 설계)

  • Park, Jinwoo;Lee, Keunhyoung;Kim, Jinmo;Hwang, Soyoung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.171-173
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    • 2015
  • This paper proposes a design method of an authoring tool for making 3D e-book using DirectX development tools. There are several functions such as generation and modification of 3D objects, modification of textures, stereoscopic modes and pictures, video export and so on in the proposed authoring tool. To support these functions, we proposes design scheme such as data structures for generating 3D objects, anaglyph method using color differences and video export method using BandiCap library.

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Brightness Temperature Retrieval using Direct Broadcast Data from the Passive Microwave Imager on Aqua Satellite

  • Kim, Seung-Bum;Im, Yong-Jo;Kim, Kum-Lan;Park, Hye-Sook;Park, Sung-Ok
    • Korean Journal of Remote Sensing
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    • v.20 no.1
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    • pp.47-55
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    • 2004
  • We have constructed a level-1 processor to generate brightness temperatures using the direct-broadcast data from the passive microwave radiometer onboard Aqua satellite. Although 50-minute half-orbit data, called a granule, are being routinely produced by global data centers, to our knowledge, this is the first attempt to process 10-minute long direct-broadcast (DB) data. We found that the processor designed for a granule needs modification to apply to the DB data. The modification includes the correction to path number, the selection of land mask and the manipulation of dummy scans. Pixel-to-pixel comparison with a reference indicates the difference in brightness temperature of about 0.2 K rms and less than 0.05 K mean. The difference comes from the different length of data between 50-minute granule and about 10-minute DB data. In detail, due to the short data length, DB data do not always have correct cold sky mirror count. The DB processing system is automated to enable the near-real time generation of brightness temperatures within 5 minutes after downlink. Through this work, we would be able to enhance the use of AMSR-E data, thus serving the objective of direct-broadcast.

Static, Buckling and Free Vibration Analyses of Fibrous Composite Plate using Improved 8-Node Strain-Assumed Finite Formulation by Direct Modification (직접수정된 8절점 가정변형률 유한요소를 이용한 복합적층판의 정적, 좌굴 및 자유진동 해석)

  • Park, Won-Tae;Chun, Kyoung-Sik;Yhim, Sung-Soon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.8 no.4
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    • pp.107-114
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    • 2004
  • In this paper, a simple improved 8-node finite element for the finite element analysis of fibrous composite plates is presented by using the direct modification. We drive explicit expressions of shape functions for the 8-node element with bilinear element geometry, which is modified so that it can represent any quadratic fields in Cartesian coordinates. The refined first-order shear deformation theory is proposed, which results in parabolic through-thickness distribution of the transverse shear strains and stresses from the formulation based on the third-order shear deformation theory. It eliminates the need for shear correction factors in the first-order theory. This finite element is further improved by combined use of assumed strain, modified shape function, and refined first-order theory. To show the effectiveness of our simple modification on the 8-node finite elements, numerical studies are carried out the static, buckling and free vibration analysis of fibrous composite plates.

MEVVA ion Source And Filtered Thin-Film Deposition System

  • Liu, A.D.;Zhang, H.X.;Zhang, T.H.;Zhang, X.Y.;Wu, X.Y.;Zhang, S.J.;Li, Q.
    • Journal of Korean Vacuum Science & Technology
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    • v.6 no.2
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    • pp.55-57
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    • 2002
  • Metal-vapor-vacuum-arc ion source is an ideal source for both high current metal ion implanter and high current plasma thin-film deposition systems. It uses the direct evaporation of metal from surface of cathode by vacuum arc to produce a very high flux of ion plasmas. The MEVVA ion source, the high-current metal-ion implanter and high-current magnetic-field-filtered plasma thin-film deposition systems developed in Beijing Normal University are introduced in this paper.

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A Proposal of the Comprehensive 'Aging in Place' Support Institution through the Analysis of the Legal System and Recognition Survey of the Elderly Housing Modification (국내의 노인주거 개조 지원 관련 법제도 현황 및 인식조사를 통한 Aging in Place 종합지원기관 도입 필요성 제안)

  • Kim, Mi-ran;Lee, Kyung-Hoon
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.34 no.10
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    • pp.75-82
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    • 2018
  • This study suggests the general support center with comprehensive services for the elderly. In general, the modifications of the elderly housing have a direct influence on the "Quality of life" and "Aging in place" for the elderly. But until now, the elderly housing modification has been carried out separately on the elderly welfare category. It is very inefficient and inconvenient for the elderly. Therefore, it is necessary to have a comprehensive organization that includes the implementation of modifications. To provide reasons for this insistence, this study analyzed the previous research, legal system guidelines, and others related things. And it researched the perception of the comprehensive institution and the need for housing modification through the recognition survey of the elderly and the early elderly. The study found that the current domestic legal system does not have an integrated system to carry out the entire process of applying and implementing the elderly housing modification. On the other hand, the results of the survey showed that the elderly hoped to introduce a comprehensive and user-friendly institution for housing modification.

A Practical Hull Form Optimization Method Using the Parametric Modification Function (파라메트릭 변환함수를 이용한 선형최적화의 실용화에 관한 연구)

  • Kim, Hee-Jung;Choi, Hee-Jong;Chun, Ho-Hwan
    • Journal of the Society of Naval Architects of Korea
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    • v.44 no.5
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    • pp.542-550
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    • 2007
  • A geometry modification is one of main keys in achieving a successful optimization. The optimized hull form generated from the geometry modification should be a realistic, faired form from the ship manufacturing point of view. This paper presents a practical hull optimization procedure using a parametric modification function. In the parametric modification function method, the initial ship geometry was easily deformed according to the variations of design parameters. For example, bulbous bow can be modified with several parameters such as bulb area, bulb length, bulb height etc. Design parameters are considered as design variables to modify hull form, which can reduce the number of design variables in optimization process and hence reduce its time cost. To verify the use of the parametric modification function, optimization for KCS was performed at its design speed (FN=0.26) and the wave making resistance is calculated using a well proven potential code with fully nonlinear free surface conditions. The design variables used are key design parameters such as Cp curve, section shape and bulb shape. This study shows that the hull form optimized by the parametric modification function brings 7.6% reduction in wave making resistance. In addition, for verification and comparison purpose, a direct geometry variation method using a bell-shape modification function is used. It is shown that the optimal hull form generated by the bell-shaped modification function is very similar to that produced by the parametric modification function. However, the total running time of the parametric optimization is six times shorter than that of the bell shape modification method, showing the effectiveness and practicalness from a designer point of view in ship yards.

Automatic Contrast Enhancement by Transfer Function Modification

  • Bae, Tae Wuk;Ahn, Sang Ho;Altunbasak, Yucel
    • ETRI Journal
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    • v.39 no.1
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    • pp.76-86
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    • 2017
  • In this study, we propose an automatic contrast enhancement method based on transfer function modification (TFM) by histogram equalization. Previous histogram-based global contrast enhancement techniques employ histogram modification, whereas we propose a direct TFM technique that considers the mean brightness of an image during contrast enhancement. The mean point shifting method using a transfer function is proposed to preserve the mean brightness of an image. In addition, the linearization of transfer function technique, which has a histogram flattening effect, is designed to reduce visual artifacts. An attenuation factor is automatically determined using the maximum value of the probability density function in an image to control its rate of contrast. A new quantitative measurement method called sparsity of a histogram is proposed to obtain a better objective comparison relative to previous global contrast enhancement methods. According to our experimental results, we demonstrated the performance of our proposed method based on generalized measures and the newly proposed measurement.