• Title/Summary/Keyword: Adaptation Time

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Loss-RTT based Differentiated Rate Adaptation Algorithm (Loss-RTT 기반 차등 전송률 조절 알고리즘에 관한 연구)

  • 김지언;정재일
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.17-20
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    • 2000
  • TCP is ill-suited to real-time multimedia applications. Its bursty transmission, and abrupt and frequent wide rate fluctuations cause high delay jitters and sudden quality degradation of multimedia applications. Deploying non congestion controlled traffic results in extreme unfairness towards competing TCP traffic. Therefore, they need to be enhanced with congestion control schemes that not only am at reducing loss ratios and improve bandwidth utilization but also are fair towards competing TCP connections. This paper proposes a differentiated rate adaptation algorithm based on loss and round trip time. Rate in a sender quickly responds to loss ratio and holds steady state. Additionally, this algorithm reduces loss ratio by loss prediction in a receiver.

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The resign of Adaptive Walsh Equalizer via LMS Algorithm with the Optimal Convergence Factor (최적 수렴인자를 갖는 LMS에 의한 적응 월쉬 등화기 설계에 관한 연구)

  • Ahn, Doo-Soo;Kim, Jong-Boo
    • Proceedings of the KIEE Conference
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    • 1991.11a
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    • pp.357-360
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    • 1991
  • In this paper, we have introduced a network and showed how this can be realised as an adaptive equalizer. The walsh equlizer is built from a set of Walsh-Block pulse functions and LMS algorithms with the optimal convergence factor(C.F.). The convergence and the adaptation speed of this algorithms depends on the proper choice of a design factor $\mu$ called the C.F.. Conventional adaptation techniques use the fixed time constant C.F. by the method of trial and error. In this paper, we propose to adaptive C.F. which are optimally tailored to adapt C.F. in real time so that their values are kept optimum for a new set of input variables.

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Implementation of an Adaptive Genetic Algorithm Processor for Evolvable Hardware (진화 시스템을 위한 유전자 알고리즘 프로세서의 구현)

  • 정석우;김현식;김동순;정덕진
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.53 no.4
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    • pp.265-276
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    • 2004
  • Genetic Algorithm(GA), that is shown stable performance to find an optimal solution, has been used as a method of solving large-scaled optimization problems with complex constraints in various applications. Since it takes so much time to execute a long computation process for iterative evolution and adaptation. In this paper, a hardware-based adaptive GA was proposed to reduce the serious computation time of the evolutionary process and to improve the accuracy of convergence to optimal solution. The proposed GA, based on steady-state model among continuos generation model, performs an adaptive mutation process with consideration of the evolution flow and the population diversity. The drawback of the GA, premature convergence, was solved by the proposed adaptation. The Performance improvement of convergence accuracy for some kinds of problem and condition reached to 5-100% with equivalent convergence speed to high-speed algorithm. The proposed adaptive GAP(Genetic Algorithm Processor) was implemented on FPGA device Xilinx XCV2000E of EHW board for face recognition.

A Study of Physiology Signal Change by Air Conditioner Temperature Change (에어컨 온도변동에 따른 생리신호 변화에 관한 연구)

  • Kum, Jong-Soo;Kim, Dong-Gyu;Kim, Hyung-Chul
    • Journal of Fisheries and Marine Sciences Education
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    • v.19 no.3
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    • pp.502-509
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    • 2007
  • This study evaluates thermal comfort by air conditioner temperature raising at the point of time that human body begins to adapt. Thermal comfort according to change of time enters by uncomfortable area gradually at general cold room temperature that magnetic pole is in human body. However, can know that keep continuous thermal comfort in case raise temperature in human body adaptation visual point. Experiments were performed in environmental chamber. Subjects were selected 4 men and 4 women whose life cycle were proved that are similar. The subjects stay in the pretesting room during the 30 minutes and enter the testing room under each experiment conditions. During the experiment, brain wave, electrocardiogram, blood pressure and thermal comfort and sensation responses were measured. In this study, physiological and psychological responses correspond under temperature raising at human body adaptation.

A Robust Model Reference Adaptive Control with a Modified $\sigma$-modification algorithm (새로운 $\sigma$-변형 알고리즘을 사용한 강인한 기준모델 적응제어)

  • 이호진;정종대;최계근
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.26 no.9
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    • pp.1322-1331
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    • 1989
  • This paper proposes a new adaptation algorithm with which a model reference adaptive control can give a local boundedness of the tracking error applied to a continuous-time linear time-invariant single-input single-output plant whose reduced-order model is of relative degree 1 and whose unmodeled dynamics may be represented in a sigular perturbation form. With the addition of an offset term and an extra adaptation structure, this algorithm is shown to have a robustness property in the sense that this gives zero residual tracking errors when the unmodeled dynamics are disappeared.

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Equalisation of Time Variant Channels Using Amplitude Banded Equaliser (진폭 분할 등화기를 이용한 시변 다중 채널의 등화)

  • 장은영;이성신;변건식
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2003.10a
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    • pp.508-511
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    • 2003
  • For the purpose of equalisation of rapidly time variant channels, We derive a novel adaptive algorithm the amplitude Banded LMS(ABLMS), which implements a non-linear adaptation based on a coefficient matrix. Then we develop the ABLMS algorithm as the adaptation procedure for a linear transversal equalise.(LTE) and a decision feedback equaliser(DFE) where a parallel adaption scheme is deployed.

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DESIGN OF ADAPTIVE CONTROLLER OF DC SERVO MOTOR (직류전동기의 적응 제어기 설계에 관한 연구)

  • Chang, S.G.;Won, J.S.
    • Proceedings of the KIEE Conference
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    • 1987.11a
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    • pp.25-28
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    • 1987
  • Design procedure of adaptive controller with variable load condition is present and applied to velocity control of small, permanent magnet DC servo motor. The state feedback control scheme is adopted and Recursive Least Squares algorithm is used for parameter estimation. In order to reduce the time consuming. In the procedure of adaptation-gain tuning of state feedback controller, approximate curve fitting technique is applied to the relations between load condition and poles of the system, load condition and feedback gains. With this method, fast adaptation can be accomplished. It is shown that this procedure can be applied not only to variable load condition but also to variation of other system constants, for example variation of resistance and inductance etc.. Simulation results is present for both cases - variable inertia load, variable motor resistance to verify performance improvements. This design procedure produces an adaptive con troller which is feasible for implementation with microprocessor by reducing calculation time.

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Adaptive Predistorter for Power Amplifier based on Real -Time Estimation of Envelope Transfer Characteristics (전력증폭기의 실시간 복소 전달함수 추정을 위한 적응 사전왜곡기의 설계 및 제작)

  • 한재희;정태식;남상욱;이광복;박면주
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.12 no.4
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    • pp.503-512
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    • 2001
  • A new adaptation algorithm for the digital predistorter is presented. The proposed technique employs the real-time transmitted signals through HPA for the table update. Hence the proposed algorithm does not depend on modulation format and the signal transmission of HPA is not affected during the adaptation process. The experimental results are presented to verify the proposed method and we obtained about 8.4 dB of ACPR improvement.

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Short utterance speaker verification using PLDA model adaptation and data augmentation (PLDA 모델 적응과 데이터 증강을 이용한 짧은 발화 화자검증)

  • Yoon, Sung-Wook;Kwon, Oh-Wook
    • Phonetics and Speech Sciences
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    • v.9 no.2
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    • pp.85-94
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    • 2017
  • Conventional speaker verification systems using time delay neural network, identity vector and probabilistic linear discriminant analysis (TDNN-Ivector-PLDA) are known to be very effective for verifying long-duration speech utterances. However, when test utterances are of short duration, duration mismatch between enrollment and test utterances significantly degrades the performance of TDNN-Ivector-PLDA systems. To compensate for the I-vector mismatch between long and short utterances, this paper proposes to use probabilistic linear discriminant analysis (PLDA) model adaptation with augmented data. A PLDA model is trained on vast amount of speech data, most of which have long duration. Then, the PLDA model is adapted with the I-vectors obtained from short-utterance data which are augmented by using vocal tract length perturbation (VTLP). In computer experiments using the NIST SRE 2008 database, the proposed method is shown to achieve significantly better performance than the conventional TDNN-Ivector-PLDA systems when there exists duration mismatch between enrollment and test utterances.

A Design of Adaptive Equalizer using the Walsh-Block Pulse Functions and the Optimal LMS Algorithms (윌쉬-블록펄스 함수와 최적 LMS알고리즌을 이용한 적응 등화기의 설계)

  • 안두수;김종부
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.8
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    • pp.914-921
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    • 1992
  • In this paper, we introduce a Walsh network and an LMS algorithm, and show how these can be realized as an adaptive equalizer. The Walsh network is built from a set of Walsh and Block pulse functions. In the LMS algorithm, the convergence factor is an important design parameter because it governs stability and convergence speed, which depend on the proper choice of the convergence facotr. The conventional adaptation techniques use a fixed time constant convergence factor by the method of trial and error. In this paper, we propose an optimal method in the choice of the convergence factor. The proposed algorithm depends on the received signal and the output of the Walsh network in real time.

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