• Title/Summary/Keyword: engineering technique

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Stamping-assisted Fabrication Technique of the Bidirectional Alignment Layer for Wide-Viewing Twisted-Nematic Liquid Crystal Displays

  • Koo, Kyung-Mo;Na, Jun-Hee;Kim, Yeun-Tae;Li, Hongmei;Lee, Sin-Doo
    • Journal of Information Display
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    • v.10 no.4
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    • pp.180-183
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    • 2009
  • A stamping-assisted rubbing technique for generating bidirectional alignment in the fabrication of wide-viewing twistednematic (TN) liquid crystal displays (LCDs) was developed. A patterned layer of a fluorinated acrylate polymer was transferred onto the first rubbed alignment layer prepared on a substrate by stamping. The fluorinated acrylate polymer provides a protective layer that covers the first alignment layer during the second rubbing process to facilitate the bidirectional alignment of the LC molecules. The LC cell in the twisted geometry with two bidirectional-alignment layers showed stable electro-optic properties and wide-viewing characteristics. The stamping-assisted rubbing technique serves as a mask-free alignment method of producing multidomains for wide-viewing LCDs.

2-DOF Control System Designed By Root Locus Technique.

  • Thepmanee, T.;Sirisantisamrid, K.;Numsomran, A.;Kongratana, V.;Tirasesth, K.
    • 제어로봇시스템학회:학술대회논문집
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    • 2000.10a
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    • pp.503-503
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    • 2000
  • This paper presents the design technique of the using of PlI, PID and PIDA Controllers in order to achieve the desired transient and steady state responses. The merit of the proposed technique is any tuning method is not being required. By using of the forward controller, so that all given specifications to be designed can be obtained via the root locus approach.

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Characteristics of a Sliding Mode Controller with Disturbance Estimator (외란 추정기를 갖는 슬라이딩 모드 제어기의 특성)

  • Choe, Seung-Bok;Ham, Jun-Ho;Park, Jong-Seong
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.1
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    • pp.165-171
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    • 2002
  • The conventional sliding mode control(SMC) technique requires a priori knowledge of the upperbounds of disturbances or/and modeling uncertainties to assure robustness. This, however, may not to be easy to obtain in practical situation. This paper presents a new methodology, sliding mode control with disturbance estimator(SMCDE), which offers a robust control performance without a priori knowledge about the disturbance. The proposed technique is featured by an average value of the imposed disturbance over a certain period. A nonlinear spring-mass-damper system is adopted as an illustrative example, and a comparative work between the conventional technique and the present one is undertaken.

The Productivity Improvement for Steel Framing Work Efficiency by Work Sampling and 5-minute Rating Technique

  • Chang, SooWon;Yi, June-Seong;Son, JeongWook
    • Journal of Construction Engineering and Project Management
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    • v.5 no.1
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    • pp.40-46
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    • 2015
  • This study presents the results of our analysis and recommendations for process and productivity improvements. The project studied consists of a 5-story research building, with a structure of steel frames supporting concrete slabs. The observations focused on the analysis of the overall erection and framing process. The methods used for the analysis consisted in intensive visits on site, where construction processes were observed in term of resources, activities, durations, materials' handling procedures, and technology used. Back to the office, authors used the information captured to model the different trades' activities, using work sampling and 5-minute rating technique. The work sampling provides insight into the activity, hence allowing for process improvements. The productivity of various trades is strongly dependent on the organization of the work process and work site conditions. Improving the productivity of the entire project or company is not possible until everyone is committed to improvement.

Source Localization Techniques for Magnetoencephalography (MEG)

  • Kwang-Ok An;Chang-Hwan Im;Hyun-Kyo Jung;Yong-Ho Lee;Hyuk-Chan Kwon
    • KIEE International Transaction on Systems and Control
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    • v.2D no.2
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    • pp.53-58
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    • 2002
  • In this paper, various aspects in magnetoencephalography (MEG) source localization are studied. To minimize the errors in experimental data, an approximation technique using a polynomial function is proposed. The simulation shows that the proposed technique yields more accurate results. To improve the convergence characteristics in the optimization algorithm, a hybrid algorithm of evolution strategy and sensitivity analysis is applied to the neuromagnetic inverse problem. The effectiveness of the hybrid algorithm is verified by comparison with conventional algorithms. In addition, an artificial neural network (ANN) is applied to find an initial source location quickly and accurately. The simulation indicates that the proposed technique yields more accurate results effectively.

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Three dimension rendering techniques in multiplanar medical images (다층의학영상의 3차원적 표현기법에 관한 연구)

  • Kim, D.W.;Song, C.H.;Cha, E.J.;Lee, T.S.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.271-274
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    • 1996
  • Shell rendering technique, which is the combined technique of surface rendering and volume rendering, was realized on workstation. By applying it to colon data acquired by CT, its validity was shown. In addition perspective projection coordinate was used for rendering the internal surface of organ and its reality was shown to be improved. This result can be use as the essential technique of virtual endoscope which is the recent hot topic in three dimensional medical imaging.

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Optimization of Steel Box Girder Bridges using Approximate Reanalysis Technique (재해석 기법을 이용한 강상자형교의 최적설계)

  • Min, Dae-Hong;Yoon, Woo-Hyun;Chung, Jee-Seung;Yang, Sung-Don
    • Journal of the Korean Society of Safety
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    • v.26 no.4
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    • pp.80-86
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    • 2011
  • Structural optimization algorithm of steel box girder bridges using improved higher-order approximate reanalysis technique is proposed in this paper. The proposed approximation method is a generalization of the convex approximation method. The order of the approximate reanalysis for each function is analytically adjusted in the optimization process. This self-adjusted capability makes the approximate structural analysis values conservative enough to maintain the optimum design point of the approximate problem. The efficiency of proposed optimazation algorithm, compared with conventional algorithm, is successfully demonstrated in the steel box girder bridges. The efficiency and robustness of proposed algorithm is also demonstrated in practical steel box girder bridges.

Robust Control of Nonlinear System using Adaptive Backstepping Technique (적응백스테핑기법을 이용한 비선형시스템 강인제어)

  • Hyun, Keun-Ho;Kim, Dong-Hun;Kim, Eung-Seok;Kim, Hong-Pil;Yang, Hai-Won
    • Proceedings of the KIEE Conference
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    • 2001.07d
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    • pp.2087-2088
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    • 2001
  • In this paper we presents a speed controller for permanent magnet synchronous motor using adaptive backstepping technique. The adaptive backstepping technique takes system nonlinearity into account in the control system design stage. The proposed control and adaptive law is proved to be asymptotically stable by the Lyapunov stability theory.

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Pulsed Electrochemical Deposition for 3D Micro Structuring

  • Park, Jung-Woo;Ryu, Shi-Hyoung;Chu, Chong-Nam
    • International Journal of Precision Engineering and Manufacturing
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    • v.6 no.4
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    • pp.49-54
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    • 2005
  • In this paper, micro structuring technique using localized electrochemical deposition (LECD) with ultra short pulses was investigated. Electric field in electrochemical cell was localized near the tool tip end region by applying pulses of a few hundreds of nano second duration, Pt-Ir tip was used as a counter electrode and copper was deposited on the copper substrate in mixed electrolyte of 0.5 M $CuSO_4$ and 0.5 M $H_2SO_4$, The effectiveness of this technique was verified by comparison with ECD using DC voltage. The deposition characteristics such as size, shape, surface, and structural density according to applied voltage and pulse duration were investigated. The proper condition was selected based on the results of the various experiments. Micro columns less than $10{\mu}m$ in diameter were fabricated using this technique. The real 3D micro structures such as micro spring and micro pattern were made by the presented method.

Structural Dynamics Modification for a Large Structure using Component Mode Synthesis Methods (구조합성법을 이용한 큰 구조물에서의 구조동특성변경법)

  • Lee, Moon-Seok;Park, Youn-Sik;Park, Young-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.11a
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    • pp.852-855
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    • 2005
  • Structural Dynamic Modification(SDM) is a technique to improve structure's dynamic characteristics by adding and removing substructures or changing material properties and shape of structures. This paper describes SDM techniques applied to a large structure with too many DOFs. The goal of this SDM technique is to modify a targe structure efficiently for its natural frequencies to avoid excitation frequencies. In this case, models reduced by Component Mode Synthesis(CMS) method that is a coupling technique are used to analyze a large structure efficiently. This paper considers a helicopter deck model with 55,000 DOFs as an application.

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