• Title, Summary, Keyword: equivalent form

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Closed Form Formulas for Equivalent Damping Ratios of a Linear Structure Equipped with Damping Devices (제진장치가 설치된 구조물의 등가감쇠비)

  • Hwang, Jae-Seung;Lee, Sang-Hyun;Min, Kyung-Won
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.370-377
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    • 2002
  • Hwang et al (2001) proposed a new method for an evaluation of equivalent damping ratios of a linear structure with linear or nonlinear damping devices. This procedure has a disadvantage that it requires time history analysis for the whole system including damping devices, which may be troublesome for practical application. To tackle this problem closed form formulas for equivalent damping ratios are proposed in this study. It is assumed that the responses of MDOF system can be reproduced by an equivalent SDOF system which vibrates in a fundamental mode. The numerical analyses of a ten-story building equipped with linear viscous damper or active mass damper or friction damper show the effectiveness of equivalent SDOF model and closed form formulas.

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A New Dual Hardy-Hilbert's Inequality with some Parameters and its Reverse

  • Zhong, Wuyi
    • Kyungpook Mathematical Journal
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    • v.49 no.3
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    • pp.493-506
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    • 2009
  • By using the improved Euler-Maclaurin summation formula and estimating the weight coefficients in this paper, a new dual Hardy-Hilbert's inequality and its reverse form are obtained, which are all with two pairs of conjugate exponents (p, q); (r, s) and a independent parameter ${\lambda}$. In addition, some equivalent forms of the inequalities are considered. We also prove that the constant factors in the new inequalities are all the best possible. As a particular case of our results, we obtain the reverse form of a famous Hardy-Hilbert's inequality.

S-Domain Equivalent System for Electromagnetic Transient Studies PART I : Frequency Dependent Network Equivalent (전자기 과도현상 해석을 위한 S 영역 등가시스템 PART I : 주파수 의존 시스템 등가)

  • 왕용필
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.11
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    • pp.632-638
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    • 2003
  • Modern power systems are very complex and to model them completely is impractical for electromagnetic transient studies. Therefore areas outside the immediate area of interest must be represented by some form of frequency dependent equivalent. The s-domain rational function form of frequency dependent equivalent does not need refitting if the simulation time-step is changed in the electromagnetic transient program. This is because the s-domain rational function coefficients are independent of the simulation time-step, unlike the z-domain rational function coefficients. S-domain rational function fitting techniques for representing frequency dependent equivalents have been developed using Least Squares Fitting(LSF). However it does not suffer the implementation error that exited in this work as it ignored the instantaneous term. This paper Presents the formulation for developing 1 Port Frequency Dependent Network Equivalent(FDNE) with the instantaneous term in S-domain and illustrates its use. This 1 port FDNE have been applied to the CIGRE Benchmark Rectifier test AC system. The electromagnetic transient package PSCAD/EMTDC is used to assess the transient response of the 1 port (FDNE) developed with Thevenin and Norton Equivalent network. The study results have indicated the robustness and accuracy of 1 port FDNE for electromagnetic transient studies.

Evaluation of the Equivalent First Modal Damping Ratio of a Structure with Additional Damping Devices (부가감쇠 장치가 설치된 구조물의 1차 모드 등가 감쇠비 산정)

  • Lee, Sang-Hyun;Min, Kyung-Won;Hwang, Jae-Seung;Lee, Young-Cheol
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.459-466
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    • 2002
  • The purpose of this study is to propose a new method for evaluating equivalent damping ratios of a structure with supplemental damping devices to assess their control effect quantitatively. A MDOF system is transformed to an equivalent SDOF system based on the assumption that the first mode dominates structural response. Approximate closed-form formulas for the evaluation of the first damping ratio are presented for various damping devices. Through numerical analysis of a ten-story building equipped with damping devices, the effectiveness of equivalent SDOF model and closed form formulas are verified.

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THE THREE DIMENSIONAL FINITE ELEMENT ANALYSIS OF STRESS ACCORDING TO IMPLANT THREAD DESIGN UNDER THE AXIAL LOAD (수직력하에서 임프란트 나사형태에 따른 응력의 3차원 유한요소법적 분석)

  • Kim, Woo-Taek;Cha, Yong-Doo;Oh, Se-Jong;Park, Sang-Soo;Kim, Hyun-Woo;Park, Yang-Ho;Park, Jun-Woo;Rhee, Gun-Joo
    • Journal of the Korean Association of Oral and Maxillofacial Surgeons
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    • v.27 no.2
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    • pp.111-117
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    • 2001
  • There are three designs of thread form in screw type implants: V-thread, Reverse buttress thread and Square thread. The purpose of this study was to find out how thread form designs have an influence on the equivalent stress, equivalent strain, maximum shear stress and maximum shear strain and which design of thread form generates more maximum equivalent stress and strain. 3-D finite element analysis was used to evaluate the stress and strain patterns of three tread types. The results of this study were as follow. 1. Under the 200N of axial load, the value of maximum equivalent stress is smallest in square thread and there is no significant difference between that of V thread and reverse buttress thread. 2. Under the 200N of axial load, the value of maximum equivalent strain is largest in V thread and smallest in square thread. 3. Under the 200N of axial load, the value of maximum shear stress is smallest in square thread and there is no significant difference between that of V thread and reverse buttress thread. 4. Under the 200N of axial load, the value of maximum equivalent strain is largest in V thread and there is no significant difference between that of square thread and reverse buttress thread. 5. Above results show that the square thread has special advantages in stress and strain compared with other thread types, especially in shear stess which is most determinant to implant-bone interface. Considering the superior biomechanical properties of square form implant, we presume that square form implant has better clinical results than the other types of implants in the same clinical conditions.

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Vitamin C requirements in main marine finfish species in Korea

  • Wang, Xiaojie;Bai, Sungchul C.
    • Proceedings of the Korean Aquaculture Society Conference
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    • pp.19-19
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    • 2003
  • This presentation reviewed the dietary vitamin C requirements in main marine finfish culture in Korea. In experiment I, an II-week feeding trial was conducted to study the effects of the different levels of dietary vitamin C on growth, tissue ascorbic acid concentrations and histopathological changes in parrot fish. Casein and gelatin based diets were formulated to contain 0, 60, 120, 240, 480 and 2000mg L-ascorbic acid (AA)kg diets on Ah equivalent basis in the form of L-ascorbyl-2-monophosphate (AMP), 60 and 240 mg AA/kg diet as L-ascorbic acid. Broken line analysis of weight gain indicated that the dietary vitamin C requirement of parrot fish is l18$\pm$12 mg AA/kg diet in the form of L-ascorbyl-2-monophosphate for maximum growth. In experiment II, a 12-week experiment was conducted to compare L-ascorbyl-2-monophosphate-Ca (AMP-Ca) with L-ascorbyl-2-monophosphate-Na/Ca (AMP-Na/Ca) for supplying the dietary vitamin C for juvenile Korean rockfish Sebastes schlegeli. Fish were fed one of 11 semi-purified diets containing equivalent of 0, 50, 100, 200, 400, and 800 mg ascorbic acid (AA)kg diet in the form of AMP-Ca or AMP-Na/Ca for 12 weeks. Broken line analysis of weight gain indicated that the dietary vitamin C requirement of Korean rockfish is 100 mg AA/kg diet in the form of AMP-Na/Ca, and 117 nag AA/kg diet in the form of AMP-Ca. In experiment III, a 12-week experiment was conducted to study the effects of different dietary levels of vitamin C, L-ascorbyl-2-polyphosphate (ASPP), on growth and tissue vitamin C concentrations in juvenile olive flounder. Fish were fed one of six semi-purified diets containing an equivalent of 0, 25, 50, 75, 150, or 1500 mg ascorbic acid (AA) kg 1 diet in the form of ASPP for 12 weeks. Based on broken line analyses for WG and PER, the optimum dietary levels of vitamin C were 91 and 93 mg AA/kg diet, respectively.

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Analysis of Attenuation Poles using Closed-form Solutions for Bandpass Filters

  • Shin, Yoon-mi;Lee, Bom-Son
    • Journal of electromagnetic engineering and science
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    • v.1 no.2
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    • pp.156-160
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    • 2001
  • Very convenient equivalent circuits fur the design of bandpass filters with an attenuation pole in the lower or upper stopband are provided together with necessary closed-form solutions. The proposed approach gives us much flexibility and simplifies the design of inserting attenuation poles.

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An INS Filter Design Considering Mixed Random Errors of Gyroscopes

  • Seong, Sang-Man;Kang, Ki-Ho
    • 제어로봇시스템학회:학술대회논문집
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    • pp.262-264
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    • 2005
  • We propose a filter design method to suppress the effect of gyroscope mixed random errors at INS system level. It is based on the result that mixed random errors can be represented by a single equivalent ARMA model. At first step, the time difference of equivalent ARMA process is performed, which consider the characteristic of indirect feedback Kalman filter used in INS filter. Next, a state space conversion of time differenced ARMA model is achieved. If the order of AR is greater than that of MA, the controllable or observable canonical form is used. Otherwise, we introduce the state equation of which the state variable is composed of the ARMA model output and several step ahead predicts of that. At final step, a complete form state equation is presented. The simulation results shows that the proposed method gives less transient error and better convergence compared to the conventional filter which assume the mixed random errors as white noise.

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Value Numbering for Java Bytecodes Optimization in CTOC (CTOC에서 자바 바이트코드 최적화를 위한 Value Numbering)

  • Kim, Ki-Tae;Kim, Ji-Min;Kim, Je-Min;Yoo, Weon-Hee
    • Journal of the Korea Society of Computer and Information
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    • v.11 no.6
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    • pp.19-26
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    • 2006
  • Redundant expressions must be eliminated in order to apply optimization for expressions in SSA Form from CTOC. This paper applied VN(Value Numbering) for this purpose. In order to carry out VN, SSAGraph must be first generated to maintain the information in the SSA Form, equivalent nodes must be found and SCC(Strongly Connected Component) generated. Equivalent nodes are assigned with an identical valnum through SCC. We could confirm elimiations for many nodes that added at SSA Form process after VN. The valnum can be applied in optimization and type inference.

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