• Title/Summary/Keyword: indirect method

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Frequency Domain Analysis for Hydrodynamic Responses of Floating Structure using Desingularized Indirect Boundary Integral Equation Method (비특이화 간접경계적분방정식 방법을 이용한 부유식 구조물의 유체동역학적 거동에 대한 주파수영역 해석)

  • Oh, Seunghoon;Jung, Dongho;Cho, Seok-kyu;Nam, Bo-woo;Sung, Hong Gun
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.1
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    • pp.11-22
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    • 2019
  • In this paper, a Rankine source method is applied and validated to analyze the hydrodynamic response of a three-dimensional floating structure in the frequency domain. The boundary value problems for radiation and diffraction problem are solved by using a desingularized indirect boundary integral equation method (DIBIEM). The DIBIEM is simpler and faster than conventional methods based on the numerical surface integration of Green's function because the singularities of Green's function are located outside of fluid regions. In case of floating structure with complex geometry, it is difficult to desingularize the singularities of Green's function consistently. Therefore a mixed approach is carried out in this study. The mixed approach is partially desingularized except singularities of the body. Wave drift loads are calculated by the middle-field formulation method that is mathematically simple and has fast convergence. In order to validate the accuracy of the developed program, various numerical simulations are carried out and these results are analyzed and compared with previously published calculations and experiments.

Speed Control of Induction Motors Using Load Torque Feedforward Control (부하토크 피드포워드 제어를 이용한 유도전동기의 속도제어)

  • 서영수;성대용;임영배
    • The Transactions of the Korean Institute of Power Electronics
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    • v.3 no.2
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    • pp.99-106
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    • 1998
  • This paper proposed a speed control system for induction motors robust to variations in torque and parameters by feedforward compensating the current portion of load torque, adding a load torque observer to the conventional PI controller in the indirect vector controlled induction motor system. Computer simulations and exeperimental works using the proposed control confirm that the transient response for the variation of the reference speed and load torque becomes improved, compared with the conventional PI controled method.

Design of neuro-fuzzy for robust control of induction motor (유도전동기의 강인 제어를 위한 뉴로-퍼지 설계)

  • 송윤재;강두영;김형권;안태천
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2004.04a
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    • pp.454-457
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    • 2004
  • In this paper, control method proposed for effective speed control of the induction motor indirect vector control. For the induction motor drive, indirect vector control scheme that controls torque current and flux current of the stator current independently so that it can have improved dynamics. Also, neuro-fuzzy algorithm employed for torque current control in order to optimal speed control The proposed neuro-fuzzy algorithm can be applied to the precise speed control of an induction motor drive system or the field of any other power systems.

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The Design of Variable Delay Line Circuit Using Indirect Frequency Synthesizer (간접 주파수 합성기를 이용한 가변 신호지연 회로 설계)

  • 윤영태;민경일;오승협
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.29A no.2
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    • pp.33-40
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    • 1992
  • The design method of signal delay line system using indirect frequency synthesizer is presented. The variable signal delay line system with 2[nsec] step of delay time at center frequency 60[MHz], bandwidth 500[KHz] and range 5.24-5.81[x10S0-6Tsec] is designed and fabricated. The results were met with good characteristics to be variable delay time of average 2.01[nsec] per step.

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A Case of Hospital Cost Analysis System by Activity-Based Costing (활동기준원가계산을 이용한 병원원가분석시스템 구축 사례)

  • 이창길;김원중
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.22 no.52
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    • pp.355-363
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    • 1999
  • As the indirect cost is increasing, ABC(Activity-Based Costing) Method that can distribute the indirect cost to each products is more effectively used. Especially for a Hospital to provide better medical service with patients, It's necessary that build ABC System to provide a regular cost information. This study proposed methodology enabling accurate cost analysis from importing concepts of ABC in a Hospital and presented a Cost Information Table for Work-Time Table and Output Services to calculate ABC.

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A Study on the Masking Data in Camera-Back Method with three-aim-point Control (Camera-Back Method 에 있어서 Masking Data에 관한 연구)

  • ChulWhoiKoo
    • Journal of the Korean Graphic Arts Communication Society
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    • v.4 no.1
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    • pp.27-35
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    • 1986
  • Following results about Y,M,C Mask are obtained by the Indirect-Screen Color Separation Method. We make use of experimental system which are in use for the student education. In the Camera-Back Method of reflection copy, the results are summerized as follows.

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A Study on the Masking Data in All-Projection Method for Transparent Copy (All-Projection Method에 있어서 Masking Data에 관한 연구)

  • ChulWhoiKoo
    • Journal of the Korean Graphic Arts Communication Society
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    • v.5 no.1
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    • pp.25-32
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    • 1987
  • Following results about Y, M, C mask are obtained by the Indirect-Screen Color Separation Method. We mark use of experimental system which are in use for the student education. In the All-Projection Method of transparency Copy, the results are summerized as follows; (omitted)

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A study on Indirect Adaptive Decentralized Learning Control of the Vertical Multiple Dynamic System

  • Lee, Soo-Cheol;Park, Seok-Sun;Lee, Jeh-Won
    • International Journal of Precision Engineering and Manufacturing
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    • v.7 no.1
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    • pp.62-66
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    • 2006
  • The learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented an iterative precision of linear decentralized learning control based on p-integrated learning method for the vertical dynamic multiple systems. This paper develops an indirect decentralized learning control based on adaptive control method. The original motivation of the learning control field was learning in robots doing repetitive tasks such as an assembly line works. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. Some techniques will show up in the numerical simulation for vertical dynamic robot. The methods of learning system are shown for the iterative precision of each link.

A Study on Indirect Adaptive Decentralized Learning Control of the Vertical Multiple Dynamic System (수직다물체시스템의 간접적응형 분산학습제어에 관한 연구)

  • Lee Soo Cheol;Park Seok Sun;Lee Jae Won
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.4
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    • pp.92-98
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    • 2005
  • The learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this specific task. In a previous work, the authors presented an iterative precision of linear decentralized learning control based on p-integrated learning method for the vertical dynamic multiple systems. This paper develops an indirect decentralized teaming control based on adaptive control method. The original motivation of the teaming control field was loaming in robots doing repetitive tasks such as on an assembly line. This paper starts with decentralized discrete time systems, and progresses to the robot application, modeling the robot as a time varying linear system in the neighborhood of the nominal trajectory, and using the usual robot controllers that are decentralized, treating each link as if it is independent of any coupling with other links. Some techniques will show up in the numerical simulation for vertical dynamic robot. The methods of learning system are shown up for the iterative precision of each link.

The Analysis of Indirect Tensile Strength (ITS) Characteristic using Physical Properties of Asphalt Mixtures (아스팔트 혼합물의 물리적 특성을 이용한 간접인장강도의 특성 분석)

  • Lee, Moon Sup
    • International Journal of Highway Engineering
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    • v.16 no.6
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    • pp.19-25
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    • 2014
  • PURPOSES : This study was performed to evaluate the possibility of Indirect Tensile Strength (ITS) as a testing method that can predict cracking on pavement. METHODS : Three asphalt binders and one kind of aggregate were used in this study, and all asphalt mixtures were produced using Gyratory Compactor followed asphalt mix design. The ITS test was performed for the mixture which are artificially short-term aged using the oven. The ITS properties were analyzed by air void, compaction temperature, asphalt content, and asphalt binder. RESULTS : The results of this study indicated that (1) the compaction temperature did not show relationship with the ITS test; (2) there was no specific trend between the asphalt content and the ITS test; (3) the ITS could reveal the property of kinds of asphalt binders; (4) the asphalt mixture that were produced at optimum temperature suggested by manufacturer did not exhibit optimum result for all asphalt binder. CONCLUSIONS : The possibility of ITS was confirmed from this study for replacement of the Marshall Stability method. However, it needs to perform in further studies of aggregate and compaction property to suggest a new ITS standard value.