• 제목/요약/키워드: half-order

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Kaiser Truss를 사용한 일방향 슬래브의 휨 거동에 관한 연구 (An Experimental Study on the Flexural Behavior of Slabs Using Kaiser Truss)

  • 김형근;곽노현;류승곤;이희발;정헌수
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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    • pp.30-35
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    • 1994
  • In order to investigate on the behavior of one-way slab with Kaiser. Truss, such as flexural strength, failure mode, and ductile capacity, a total of twenty specimens have been tested and compared with the R.C slab without Kaiser Truss. The major variables are Kaiser Truss intervals(30, 40, 60cm), half slab thickness. Test results showed that support interval of half pc slab can be determined by the flexural strength which causes the concrete crack and there are horizontal cracks between upper concrete and half slab in the connection of the specimen with kaiser truss interval 60cm.

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낙동강 하구의 조석변화에 따른 Heterotrophic Activity의 계절적 변화와 염분의 영향 (Seasonal Variation of Heterotrophic Activity in the Estuary of Naktong River over Half Tidal Cycle and Salinity Effect)

  • 안태영;박중찬;하영칠
    • 미생물학회지
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    • 제29권5호
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    • pp.339-343
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    • 1991
  • Heterotrophic activity, total bacteria and salinity were determined seasonally in the estuary of Naktong River over half tidal cycle. Heterotrophic activity was determined by the uptake of [U- $^{14}$ C]glucose. Heterotrophic activity fluctuated with the tides and was decreased as salinity increased. Teh great activity occurred near low ebb tide at all seasons except summer. The main environmental factor affecting hetreotrophic activity was the salinity rather than water temperature in the estuary of Naktong River. In order to estimate the effect of salt, salt was added to estuarine water. Vmax for glucose of salt-added water was 17% and 77% of original estuarine water at station 1 and 2 respectively and slight increase was observed at station 3. Respiration rate and Kt+Sn for glucose of salt-added sample increased at all 3 stations. The increase of the Kt value implies the reduced affinity of bacterial population for glucose. The effects of salinity on the heterotrophic activity were more extensive in the upper region of estuary than at the mouth.

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Half Bridge LLC 공진 컨버터를 이용한 파워 LED의 정전류 적응제어기 (Adaptive Current Control of Power LEDs Using Half-Bridge LLC Resonant Converter)

  • 김응석;김영태
    • 조명전기설비학회논문지
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    • 제27권4호
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    • pp.48-53
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    • 2013
  • In general, the LLC resonant topology consists of three stages as; square wave generator, resonant network, and rectifier network. LLC resonant converter has the time slowly varying parameters. However, the power LEDs as the load of LLC converter can be regarded as fast time varying parameters. In this paper, the mathematical model of half-bridge resonant converter including with the power LEDs is introduced for the current controller design model. Using this controller design model, the parameter adaptive output feedback controller will be designed to control the power LEDs current. In order to show the validities of the proposed model, the parameter adaptive output feedback controller, the experimental investigation will be presented.

A Tightly Regulated Triple Output Asymmetrical Half Bridge Flyback Converter

  • Hyeon, Byeong-Cheol;Cho, Bo-Hyung
    • Journal of Power Electronics
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    • 제10권1호
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    • pp.14-20
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    • 2010
  • In this paper, a tightly regulated triple output asymmetrical half bridge flyback (ASHF) converter is proposed. In order to regulate all output voltages, pulse frequency modulation (PFM), pulse width modulation (PWM) and phase delay (PD) are used simultaneously. In comparison with the conventional PWM-PD method, the interactions among the control variables are minimized and the operating range is increased. By the utilization of a multi winding transformer, the auxiliary transformer and the blocking capacitor are eliminated and the size and cost of the proposed converter is reduced. The operation principle of the converter is explained and the modes of operation are investigated. Based on the results, the steady state characteristics of the converter are explored. A 24V/10A, 12V/5A, 5V/10A hardware prototype is built and tested to verify the analysis results and the voltage regulation of the triple outputs of the proposed converter.

반무한영역 문제에 대한 유한요소와 경계요소의 조합 (A Coupling of Finite Elements and Boundary Elements for Half Plane Problems)

  • 김문겸;임윤묵
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1988년도 가을 학술발표회 논문집
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    • pp.49-54
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    • 1988
  • A procedure which may be useful in dealing with problems of half plane is considered. Boundary elements are combined with finite elements to facilitate their merits. Boundary elements for semi-infinite region are composed using the Melan's solution for half plane. Finite elements are used to model irregurarity or the nonhomogeneity of materials, which is usual in underground structures. In order to verify the procedure, a shallow tunnel under internal pressure is analysed using the finite element method, the boundary element method, and the combined method. It is shown that the developed Procedure is accurate enough compared with other method.

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Investigation of PID Fuzzy Controller for Output Voltage Regulation of Current-Doubler-Rectified Asymmetric Half-Bridge DC/DC Converter

  • Chung, Gyo-Bum
    • Journal of Power Electronics
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    • 제7권1호
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    • pp.21-27
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    • 2007
  • This paper investigates a PID fuzzy controller for output voltage regulation of a current-doubler-rectified asymmetric half-bridge (CDRAHB) DC/DC converter. The controller is a PD-type fuzzy controller in parallel with a linear integral controller. The PD type fuzzy controller is for providing the varying gain at the different operating conditions to regulate the output voltage. The linear integral controller is for removing the steady-state error of the output voltage. In order to show the outstanding dynamic characteristics of the proposed controller, PSIM simulation studies are carried out and compared to the results for which the conventional loop gain design method is used.

Takagi-Sugeno Fuzzy Integral Control for Asymmetric Half-Bridge DC/DC Converter

  • Chung, Gyo-Bum
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제7권1호
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    • pp.77-84
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    • 2007
  • In this paper, Takagi-Sugeno (TS) fuzzy integral control is investigated to regulate the output voltage of an asymmetric half-bridge (AHB) DC/DC converter; First, we model the dynamic characteristics of the AHB DC/DC converter with state-space averaging method and small perturbation at an operating point. After introducing an additional integral state of the output regulation error, we obtain the $5^{th}$-order TS fuzzy model of the AHB DC/DC converter. Second, the concept of the parallel distributed compensation is applied to design the fuzzy integral controller, in which the state feedback gains are obtained by solving the linear matrix inequalities (LMIs). Finally, simulation results are presented to show the performance of the considered design method as the output voltage regulator and compared to the results for which the conventional loop gain method is used.

유한요소와 경계요소의 조합에 의한 반무한 영역 문제의 비선형해석 (A Nonlinear Analysis of Half Plane Problems Using Coupling of Finite Elements and Boundary Elements)

  • 김문겸;임윤묵
    • 전산구조공학
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    • 제2권1호
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    • pp.55-64
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    • 1989
  • 본 논문에서는 경계요소법과 비선형 유한요소법의 각 장점을 이용하여 반무한 영역을 가진 구조체의 해석방법을 논하였다. 여기서, 반무한 경계요소는 Melan의 반무한 평면에 대한 해로부터 구성하였다. 비선형 유한요소는 지하구조물에서 주로 접할 수 있는 탄소성 재료의 비균질성 또는 불규칙성을 모형화하기 위하여 사용하였다. 본 조합방법의 검증을 위하여 얕은 터널에 일정한 내압이 작용하는 경우를 택하여, 비선형 유한요소법과 조합방법의 결과를 비교하였다. 비교결과, 개발된 조합방법이 다른 해석방법에 비해 충분한 정확도를 가짐을 알 수 있었다.

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다층 반무한 기본해를 이용한 경계요소해석 (Boundary Element Method for Multilayered Media Using Numerical Fundamental Solutions)

  • 김문겸;오금호;김민규;박준상
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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    • pp.79-86
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    • 1996
  • A boundary element method which utilizes the fundamental solution in the half plane is developed to analyze the multi-layered elastic media. The objective of this study is to derive numerically the fundamental solutions and to apply those to the exterior multi-layered domain problems. To obtain numerical fundamental solutions of multi-layered structural system, the same number of solutions as that of layers in Fourier transform domain are employed. The numerical integration technique is used in order to inverse the Fourier transform solution to real domain. To verify the proposed boundary element method, two examples are treated: (1) a circular hole near the surface of a half plane; and (2) a circular cavity within one layer of four layered half plane.

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Moments and Estimation From Progressively Censored Data of Half Logistic Distribution

  • Sultan, K.S.;Mahmoud, M.R.;Saleh, H.M.
    • International Journal of Reliability and Applications
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    • 제7권2호
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    • pp.187-201
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    • 2006
  • In this paper, we derive recurrence relations for the single and product moments of progressively Type-II right censored order statistics from half logistic distribution. Next, we derive the maximum likelihood estimators (MLEs) of the location and scale parameters of the half logistic distribution. In addition, we use the setup proposed by Balakrishnan and Aggarwala (2000) to compute the approximate best linear unbiased estimates (ABLUEs) of the location and scale parameters. Finally, we point out a simulation study to compare between the efficiency of the techniques considered for the estimation.

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