• Title/Summary/Keyword: Compensation Problem

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Formulation of an Optimal Compensation Method for Differential Column Shortening in Highrise Buildings (고층건물 기둥 부등축소량의 최적보정기법 정식화)

  • 김기봉;박효선
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1999.10a
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    • pp.370-377
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    • 1999
  • Differential shortenings of columns in a highrise building must be considered in the design process to avoid unexpected damages in structural and nonstructural elements. While research activity has been reported in the literature on the development of estimation algorithms or prediction procedures of elastic and inelastic column shortenings, no algorithms or methods for compensation of differential shortenings. In this paper a compensation method for differential column shortenings in a high-rise is formulated as an optimization problem The simulated annealing algorithm is used to find optimal solutions. The performance of the proposed method is presented by using the well known examples developed by PCA.

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Current Reference Compensation for Fast Response in PCMC of PSFB Converter (PSFB 컨버터의 PCMC에서 빠른 응답특성을 가지기 위한 전류 명령 보상)

  • Lee, Jong-Uk;Kim, Hag-Wone;Baek, Seung-Woo;Cho, Kwan-Yuhl
    • The Transactions of the Korean Institute of Power Electronics
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    • v.23 no.2
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    • pp.147-151
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    • 2018
  • Phase-shift fullbridge (PSFB) converter detects the current in the primary side for operation of the peak current mode controller (PCMC). The PCMC must used the slope compensation to solve the problem when the effective duty is over 0.5. The voltage response of PSFB converters has slower than that of buck converter because of slew interval even if the voltage controllers of two converters have same bandwidth. To overcome these problems, this work proposes a compensating method of current reference considering slew interval and fast response in the PSFB converter. The effectiveness of the proposed method is proven using the PSIM simulation and experiment.

Constant Altitude Flight Control for Quadrotor UAVs with Dynamic Feedforward Compensation

  • Razinkova, Anastasia;Kang, Byung-Jun;Cho, Hyun-Chan;Jeon, Hong-Tae
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.14 no.1
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    • pp.26-33
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    • 2014
  • This study addresses the control problem of an unmanned aerial vehicle (UAV) during the transition period when the flying mode changes from hovering to translational motion in the horizontal plane. First, we introduce a compensation algorithm that improves height stabilization and reduces altitude drop. The main principle is to incorporate pitch and roll measurements into the feedforward term of the altitude controller to provide a larger thrust force. To further improve altitude control, we propose the fuzzy logic controller that improves system behavior. Simulation results presented in the paper highlight the effectiveness of the proposed controllers.

Compensation of OLED Degradation by AMOLED Pixel Circuit

  • Choi, Sang-Moo;Goo, Bon-Seok;Kang, Jin-Goo;Kim, Keum-Nam;Kim, Yang-Wan;Choi, Woong-Sik;Kim, Byung-Hee
    • 한국정보디스플레이학회:학술대회논문집
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    • 2009.10a
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    • pp.466-469
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    • 2009
  • The life time of AMOLED displays has been dependent on OLED materials up to this point. In particular, image sticking (burn-in) has been one of the most critical issues for AMOLEDs. This paper proposes image sticking compensation AMOLED pixel circuits to address the problem without requiring process or material improvements to the OLED itself. We verified the performance of those circuits by simulation and actual panel implementation.

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A Current Differential Relaying Algorithm for Transmission Lines Using an Advanced Compensation Algorithm of CTs (보상알고리즘을 적용한 송전선 보호용 전류차동 알고리즘)

  • Kang, Y.C.;Lim, U.J.;Choi, J.W.;Jin, S.Y.;Cho, H.Y.
    • Proceedings of the KIEE Conference
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    • 2003.07a
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    • pp.323-325
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    • 2003
  • A current differential relay may maloperate for external faults with CT saturation and requires an additional method to cope with the problem. This paper proposes a current differential relaying algorithm for transmission line protection using an advanced compensation algorithm of the secondary current of CTs. The compensation algorithm is unaffected by a remanent flux. The proposed algorithm does not need an additional method for CT saturation and thus can achieve high stability for an external fault.

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LP-Based Blind Adaptive Channel Identification and Equalization with Phase Offset Compensation

  • Ahn, Kyung-Sseung;Baik, Heung-Ki
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.28 no.4C
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    • pp.384-391
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    • 2003
  • Blind channel identification and equalization attempt to identify the communication channel and to remove the inter-symbol interference caused by a communication channel without using any known trainning sequences. In this paper, we propose a blind adaptive channel identification and equalization algorithm with phase offset compensation for single-input multiple-output (SIMO) channel. It is based on the one-step forward multichannel linear prediction error method and can be implemented by an RLS algorithm. Phase offset problem, we use a blind adaptive algorithm called the constant modulus derotator (CMD) algorithm based on condtant modulus algorithm (CMA). Moreover, unlike many known subspace (SS) methods or cross relation (CR) methods, our proposed algorithms do not require channel order estimation. Therefore, our algorithms are robust to channel order mismatch.

Path compensation toward direct shape control: dealing with tool deflection problem in 2D contour machining (직접형상제어를 위한 공구경로의 보상 : 2D 윤곽가공의 공구휨을 중심으로)

  • Cho, Jung-Hoon;Suh, Suk-Hwan
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.2
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    • pp.97-111
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    • 1995
  • In this paper, we investigate path compensation scheme for the machining errors due to tool deflection in 2D contour machining. The significance of the deflection error is first shown by experiments, and a direct compensation scheme is sought. In the presented scheme, the tool path is evaluated and correcte based on the instantaneous deflection force model, until the desired contour can be obtained under the presence of tool deflection in actual machining. In the sense that the developed method estimates and compensates the machining errors via modifying the tool path, it is distinguished from the previous approach based on geometric simulation and cutting simulation. Further, it can be viewed as a direct and active method toward direct shape control in CNC machining. Simulation results are included to show the validity and adequacy of the path-modification scheme under various cutting conditions.

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A Case Study on the Importance of Residual Compensation in FRF-based Substructuring (주파수 응답함수를 이용한 부분구조 합성에서 모드자름 오차 보정에 관한 수치적 연구)

  • 박윤식;김경호
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.4
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    • pp.302-309
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    • 2002
  • A FRF-based substructuring method attempts to predict the dynamic characteristics of a complex structure from predetermined FRFs of the comprising uncoupled substructures. Although this method has the advantage of being able to incorporate experimental component FRFs directly, it is prone to errors : measurement errors, coordinate incompleteness, modal incompleteness, etc. Among the various sources of errors, this paper deals with the problem of modal incompleteness (or residual problem) of which importance is underestimated compared to others. It is a well-known rule of thumb that such a problem can be overcome by including modes up to 2 or 3 times the upper frequency of interest. Using a simulated case study, it is demonstrated that even including modes up to 20 times the upper frequency of interest does not guarantee a satisfactory result. A method to compensate the residual errors is introduced. This method requires the whole FRF matrices of substructures which is practically impossible for a complex structure. An applicable alternative is suggested and applied successfully to the case study. Finally, the effects of measurement errors on the residual compensation are also discussed.

The Liability for Damage and Dispute Settlement Mechanism under the Space Law (우주법상 손해배상책임과 분쟁해결제도)

  • Lee, Kang-Bin
    • Journal of Arbitration Studies
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    • v.20 no.2
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    • pp.173-198
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    • 2010
  • The purpose of this paper is to research on the liability for the space damage and the settlement of the dispute with reference to the space activity under the international space treaty and national space law of Korea. The United Nations has adopted five treaties relating to the space activity as follows: The Outer Space Treaty of 1967, the Rescue and Return Agreement of 1968, the Liability Convention of 1972, the Registration Convention of 1974, and the Moon Treaty of 1979. All five treaties have come into force. Korea has ratified above four treaties except the Moon Treaty. Korea has enacted three national legislations relating to space development as follows: Aerospace Industry Development Promotion Act of 1987, Outer Space Development Promotion Act of 2005, Outer Space Damage Compensation Act of 2008. The Outer Space Treaty of 1967 regulates the international responsibility for national activities in outer space, the national tort liability for damage by space launching object, the national measures for dispute prevention and international consultation in the exploration and use of outer space, the joint resolution of practical questions by international inter-governmental organizations in the exploration and use of outer space. The Liability Convention of 1972 regulates the absolute liability by a launching state, the faulty liability by a launching state, the joint and several liability by a launching state, the person claiming for compensation, the claim method for compensation, the claim period of compensation, the claim for compensation and local remedy, the compensation amount for damage by a launching state, the establishment of the Claims Commission. The Outer Space Damage Compensation Act of 2008 in Korea regulates the definition of space damage, the relation of the Outer Space Damage Compensation Act and the international treaty, the non-faulty liability for damage by a launching person, the concentration of liability and recourse by a launching person, the exclusion of application of the Product Liability Act, the limit amount of the liability for damage by a launching person, the cover of the liability insurance by a launching person, the measures and assistance by the government in case of occurring the space damage, the exercise period of the claim right of compensation for damage. The Liability Convention of 1972 should be improved as follows: the problem in respect of the claimer of compensation for damage, the problem in respect of the efficiency of decision by the Claims Commission. The Outer Space Damage Compensation Act of 2008 in Korea should be improved as follows: the inclusion of indirect damage into the definition of space damage, the change of currency unit of the limit amount of liability for damage, the establishment of joint and several liability and recourse right for damage by space joint launching person, the establishment of the Space Damage Compensation Review Commission. The 1998 Final Draft Convention on the Settlement of Disputes Related to Space Activities of 1998 by ILA regulates the binding procedure and non-binding settlement procedure for the disputes in respect of space activity. The non-binding procedure regulates the negotiation or the peaceful means and compromise for dispute settlement. The binding procedure regulates the choice of a means among the following means: International Space Law Court if it will be established, International Court of Justice, and Arbitration Court. The above final Draft Convention by ILA will be a model for the innovative development in respect of the peaceful settlement of disputes with reference to space activity and will be useful for establishing the frame of practicable dispute settlement. Korea has built the space center at Oinarodo, Goheung Province in June 2009. Korea has launched the first small launch vehicle KSLV-1 at the Naro Space Center in August 2009 and June 2010. In Korea, it will be the possibility to be occurred the problems relating to the international responsibility and dispute settlement, and the liability for space damage in the course of space activity. Accordingly the Korean government and launching organization should make the legal and systematic policy to cope with such problems.

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The Improvement of Motion Compensation for a Moving Target Using the Gabor Wavelet Transform (Gabor Wavelet Transform을 이용한 움직이는 표적에 대한 움직임 보상 개선)

  • Shin, Seung-Yong;Myung, Noh-Hoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.10 s.113
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    • pp.913-919
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    • 2006
  • This paper presents a technique for motion compensation of ISAR(Inverse SAR) images for a moving target. If a simple fourier transform is employed to obtain ISAR image for a moving target, the image is usually blurred. These images blurring problem can be solved with the time-frequency transform. In this paper, motion compensation algorithms of ISAR image such as STFT(Short Time Fourier Transform), GWT(Gabor Wavelet Transform) are described. In order to show the performances of each algorithm, we use scattering wave of the ideal point scatterers and simulated MIG-25 to obtain motion compensated ISAR image, and display the resolution of STFT and GWT ISAR image.