• Title/Summary/Keyword: hybrid systems

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A Study on the PAPR Reduction by Hybrid Algorithm Based on the PTS and GS Technique

  • Zhao Zi-Bin;Kim Young-Hwan;Kim Jae-Moung
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.31 no.2A
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    • pp.187-193
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    • 2006
  • Multicarrier systems has major shortcomings due to the large numbers of subcarrier. One of the shortcomings is the high peak-to-average power ratio(PAPR), which causes nonlinearity distortion in the transmitter, and degrades the performance of the system significantly. Partial transmit sequence(PTS) is one of the best approaches that can significantly improve the statistics of the PAPR of an orthogonal frequency division multiplexing(OFDM) signal. Guided scrambling(GS) is an extension of self-synchronizing scrambling. It is also capable of guiding the scrambling process to produce a balanced encoded bit stream. In this paper, we propose a sub-optimal algorithm to optimize the phase factor in PTS. In addition, we integrate GS coding with this method. The proposed Hybrid algorithm can get much more PAPR reduction at the expense of incur a few error extension and do not require transmission of side information.

Optimization of Fuzzy Set Fuzzy Model by Means of Hierarchical Fair Competition-based Parallel Genetic Algorithms (계층적 경쟁기반 병렬 유전자 알고리즘을 이용한 퍼지집합 퍼지모델의 최적화)

  • Choi, Jeoung-Nae;Oh, Sung-Kwun;Hwang, Hyung-Soo
    • Proceedings of the KIEE Conference
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    • 2006.07d
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    • pp.2097-2098
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    • 2006
  • In this study, we introduce the hybrid optimization of fuzzy inference systems that is based on Hierarchical Fair Competition-based Parallel Genetic Algorithms (HFCGA). HFCGA is a kind of multi-populations of Parallel Genetic Algorithms(PGA), and it is used for structure optimization and parameter identification of fuzzy set model. It concerns the fuzzy model-related parameters as the number of input variables, a collection of specific subset of input variables, the number of membership functions, and the apexes of the membership function. In the hybrid optimization process, two general optimization mechanisms are explored. The structural optimization is realized via HFCGA method whereas in case of the parametric optimization we proceed with a standard least square method as well as HFCGA method as well. A comparative analysis demonstrates that the proposed algorithm is superior to the conventional methods.

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Hybird Identification of IG baed Fuzzy Model (정보 입자 기반 퍼지 모델의 하이브리드 동정)

  • Park, Keon-Jun;Lee, Dong-Yoon;Oh, Sung-Kwun
    • Proceedings of the KIEE Conference
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    • 2005.07d
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    • pp.2885-2887
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    • 2005
  • We introduce a hybrid identification of information granulation(IG)-based fuzzy model to carry out the model identification of complex and nonlinear systems. To optimally design the IG-based fuzzy model we exploit a hybrid identification through genetic alrogithms(GAs) and Hard C-Means (HCM) clustering. An initial structure of fuzzy model is identified by determining the number of input, the seleced input variables, the number of membership function, and the conclusion inference type by means of GAs. Granulation of information data with the aid of HCM clustering help determine the initial paramters of fuzzy model such as the initial apexes of the membership functions and the initial values of polyminial functions being used in the premise and consequence part of the fuzzy rules. And the inital parameters are tuned effectively with the aid of the GAs and the least square method. Numerical example is included to evaluate the performance of the proposed model.

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Low Density Parity Check Codes for Hybrid ARQ System

  • Kim, Woo-Tae;Kim, Jeong-Goo;Joo, Eon-Kyeong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.32 no.4C
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    • pp.370-378
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    • 2007
  • The most appropriate low density parity check (LDPC) code for hybrid automatic repeat request (HARQ) system suitable for future multimedia communication systems is presented in this paper. HARQ system with punctured LDPC code is investigated at first. And two transmission schemes with parallel concatenated LDPC code are also presented and their performances are analyzed according to the various values of mean column weight (MCW). As a result, the parallel concatenated LDPC code with the diversity effect of information bit is considered to be more appropriate for HARQ system considering the throughput as well as error performance.

Fuzzy Hybrid Control of Rhino XR-2 Robot (Rhino XR-2 로보트의 퍼지 혼성 제어)

  • Byun, Dae-Yeal;Sung, Hong-Suk;Lee, Kwae-Hi
    • Proceedings of the KIEE Conference
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    • 1993.11a
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    • pp.299-303
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    • 1993
  • There can be two methods in control systems: one is to use a linear controller, the other is to use a nonlinear controller. The PID controller and the fuzzy controller can be said to belong the linear and the nonlinear controller respectively. In this paper, a new hybrid controller which is consist of the linear PID controller of which the gain is tuned and the nonlinear self tuning fuzzy controller is proposed. In the PID controller, an algorithm which parameterizes the proportional, the intergral, and the derivative gain as a single parameter is used to improve the performance of the PID controller. In the self tuning fuzzy controller, an algorithm which changes the shape of the triangle membership function and changes the scaling factor which is multiplied to the error and the error change. The evaluation of the performance of the suggested algorithm is carried on by the simulation for the Rhino XH-2 robot manipulator with 5 links revolute joints.

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EMG-based Hybrid Assistive Leg for Walking Aid using Feedforward Controller

  • Kawamoto, Hiroaki;Sankai, Yoshiyuki
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.32.2-32
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    • 2001
  • We have developed the power assistive leg called HAL (Hybrid Assistive Leg) which provide the walking aid for walking disorder persons or aged persons without nursing person. We developed HAL-3 by considering some problems of HAL-1,2 which had developed previously. The mechanism of HAL-3 actuator could be simplified and sophisticated by using the harmonic drive. As the control signal of HAL-3 EMG signal was used. We proposed a calibration method to identify parameters which relates the EMG to joint torque by using HAL-3. We could obtain suitable torque estimated by EMG and realize power assist in walking according to the intention of the operator To the remove discomfort for quick motion power assist, the feedforward controller was installed at the beginning of motion ...

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Fuzzy PI-PLL Control for DC Motors

  • Kuc, Tae-Yong;Tefsuya, Muraoka
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.85.1-85
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    • 2001
  • A phase lock loop (PLL) circuit is a wellknown electronic circuit in communication engineering and other areas. In this paper, we present application of the PLL and fuzzy logic for DC motor control which are mixed well to be more effective for motor control. With this scheme, the control system can reach the set point rapidly, especially, it can eliminate noises. In addition, the PLL makes the system to have more stability; whereas, fuzzy logic controls helping PLL to be able to lock rapidly for a good response. The experiment result shows that the proposed control system works more efficacious. By performance comparison between the pure PLL control and the hybrid architecture of PLL with the fuzzy control, the result reveals the hybrid control ...

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Hybrid Position/Force Control of Robot Manipulator using Fuzzy Logic Control

  • Ahn, Ihn-Seok;ahn, Kwang-Seok;Kim, Sang-Bin;Jang, Jun-Oh;Park, Sang-Bae
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.129.5-129
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    • 2001
  • When a robot manipulator performs some task like grinding or assembling, not only the position control but also the force control of the tools connected to the robot must be controlled. But at this time We were received the uncertainty problems of system information for the force control, for example disturbance, senor resolution and measurement noise. Therefore we proposed fuzzy logic control method instead of existing control theory for the robot manipulator control, for example PID control method. In this paper, We proposed hybrid position/force control of robot manipulator using fuzzy logic control method. To show the validity of the proposed fuzzy controller, We compared fuzzy controller with conventional PID controller.

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A realization Fuzzy PI and Fuzzy PD Controller using a compensation Fuzzy Algorithms

  • Kim, Seung-Cheol;Choo, Yeon-Gyu;Kang, Shin-Chul;Lim, Young-Do;Park, Boo-Kwi;Lee, Ihn-Yong
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.101.4-101
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    • 2002
  • I. Introduction ▶The PID(Proportional-Integral-Derivative) controller is widely used in the industry it can be implemented easily for a typical second order plant. ▶The parameters of PID controller should be adapted complicatedly if a plant is various or the load is present. ▶For solving the problem, many control techniques have been developed. ▶A major method is a hybrid Fuzzy-PID controller. But, in case of using this method, we can not obtain characteristic of rapidly response and not achieved compensation on disturbance. ▶Therefore, we will use compensator fuzzy controller a front Hybrid type fuzzy-PID controller...

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Development of A Hybrid Type Electronic Brake System(EBS)

  • Lim, Chulki;Boo, Kwangsuck;Song, Jeonghoon;Hong, Soonyoung
    • 제어로봇시스템학회:학술대회논문집
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    • 2002.10a
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    • pp.115.1-115
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    • 2002
  • This study proposes a new conceptual Hybrid Electric Brake System (HEBS) which overcomes the problems of the conventional hydraulic brake system. The HEBS uses the contactless brake system when vehicle speed is high to obtain superior braking force by eddy current, which is induced in pole area by magnetic flux through a rotating conductive disk. On the contrary, when a vehicle speed is low, contact type brake system such as conventional hydraulic brake system makes higher braking force. HEBS transfers faster a braking intention of drivers and guarantees a safety of drivers because of vehicle dynamic superior controllability. Braking torque analysis is peformed based upon Lee. Barn\ulcornermath...

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