• Title/Summary/Keyword: Adaptive Search

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Motion Estimation Algorithm Using Variance and Adaptive Search Range for Frame Rate Up-Conversion (프레임 율 향상을 위한 분산 및 적응적 탐색영역을 이용한 움직임 추정 알고리듬)

  • Yu, Songhyun;Jeong, Jechang
    • Journal of Broadcast Engineering
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    • v.23 no.1
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    • pp.138-145
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    • 2018
  • In this paper, we propose a new motion estimation algorithm for frame rate up-conversion. The proposed algorithm uses the variance of errors in addition to SAD in motion estimation to find more accurate motion vectors. Then, it decides which motion vectors are wrong using the variance of neighbor motion vectors and the variance between current motion vector and neighbor's average motion vector. Next, incorrect motion vectors are corrected by weighted sum of eight neighbor motion vectors. Additionally, we propose adaptive search range algorithm, so we can find more accurate motion vectors and reduce computational complexity at the same time. As a result, proposed algorithm improves the average peak signal-to-noise ratio and structural similarity up to 1.44 dB and 0.129, respectively, compared with previous algorithms.

Effective Capon Beamforming Robust to Steering Vector Errors (조향벡터 에러에 강인한 효과적인 Capon 빔 형성기법)

  • Choi, Yang-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.48 no.5
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    • pp.115-122
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    • 2011
  • Adaptive arrays suffer from severe performance degradation when there are errors in the steering vector. The DCRCB (doubly constrained robust Capon beamformer) overcomes such a problem, introducing a spherical uncertainty set of the steering vector together with a norm constraint. However, in the standard DCRCB, it is a difficult task to determine the bound for the uncertainty, the radius of the spherical set, such that a near best solution is obtained. A novel beamforming method is presented which has no difficulty of the uncertainty bound setting, employing a recursive search for the steering vector. Though the basic idea of recursive search has been known, the conventional recursive method needs to set a parameter for the termination of the search. The proposed method terminates it by using distances to the signal subspace, without the need for parameter setting. Simulation demonstrates that the proposed method has better performance than the conventional recursive method and than the non-recursive standard DCRCB, even the one with the optimum uncertainty bound.

Adaptive Link Recovery Period Determination Algorithm for Structured Peer-to-peer Networks (구조화된 Peer-to-Peer 네트워크를 위한 적응적 링크 복구 주기 결정 알고리듬)

  • Kim, Seok-Hyun;Kim, Tae-Eun
    • Journal of Digital Contents Society
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    • v.12 no.1
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    • pp.133-139
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    • 2011
  • Structured P2P (peer-to-peer) networks have received much attention in research communities and the industry. The data stored in structured P2P networks can be located in a log-scale time without using central severs. The link-structure of structured P2P networks should be maintained for keeping log-scale search performance of it. When nodes join or leave structured P2P networks frequently, some links become unavailable and search performance is degraded by these links. To sustain search performance of structured P2P networks, periodic link recovery scheme is generally used. However, when the link recovery period is short or long compared with node join and leave rates, it is possible that sufficient number of links are not restored or excessive messages are used after the link-structure is restored. We propose the adaptive link recovery determination algorithm to maintain the link-structure of structured P2P networks when the rates of node joining and leaving are changed dynamically. The simulation results show that the proposed algorithm can maintain similar QoS under various node leaving rates.

Fractal Depth Map Sequence Coding Algorithm with Motion-vector-field-based Motion Estimation

  • Zhu, Shiping;Zhao, Dongyu
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.9 no.1
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    • pp.242-259
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    • 2015
  • Three-dimensional video coding is one of the main challenges restricting the widespread applications of 3D video and free viewpoint video. In this paper, a novel fractal coding algorithm with motion-vector-field-based motion estimation for depth map sequence is proposed. We firstly add pre-search restriction to rule the improper domain blocks out of the matching search process so that the number of blocks involved in the search process can be restricted to a smaller size. Some improvements for motion estimation including initial search point prediction, threshold transition condition and early termination condition are made based on the feature of fractal coding. The motion-vector-field-based adaptive hexagon search algorithm on the basis of center-biased distribution characteristics of depth motion vector is proposed to accelerate the search. Experimental results show that the proposed algorithm can reach optimum levels of quality and save the coding time. The PSNR of synthesized view is increased by 0.56 dB with 36.97% bit rate decrease on average compared with H.264 Full Search. And the depth encoding time is saved by up to 66.47%. Moreover, the proposed fractal depth map sequence codec outperforms the recent alternative codecs by improving the H.264/AVC, especially in much bitrate saving and encoding time reduction.

Design of an Adaptive Fuzzy Controller using Genetic Algorithm (유전알고리즘을 이용한 적응 퍼지 제어기의 설계)

  • Huh, Sung-Hoe;Seo, Ho-Joon;Park, Jang-Hyun;Yun, Pil-Sang;Park, Gwi-Tae
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.530-532
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    • 1999
  • In adaptive fuzzy control, system designer develops an adaptive law for the output of the unknown plant to track a given signal. The adaptation gains of the adaptive law are critical elements in the overall system, however, they were used to be selected by the designer's experience or intuition. In this paper, genetic algorithm is used to search an optimal adaptation gain and simulation results will be presented to show the improved tracking responses.

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The Development and Performance Evaluation of Adaptive Monitoring sensor for the Marine IT System (해양 IT시스템용 적응형 모니터링 센서의 개발 및 성능 평가)

  • Cho, Jeong-Hwan;Roh, Hee-Jung
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.6
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    • pp.90-95
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    • 2015
  • This paper proposes the new adaptive gain control monitoring sensor for the marine IT system. The marine IT system sensors make it possible to conduct search missions, record climate changes, provide pollution control, study marine life, conduct survey missions, tactical surveillance, and predict natural disturbances in the ocean. In this paper, the adaptive gain control circuit which changes its parameters according to the ambient noise situation for obtaining the precise location information of marine IT system sensor is developed and analyzed. The performance characteristics for ensuring the precise location information of marine system sensor is presented and analyzed. The theoretical and experimental studies have been carried out. The presented results from the above investigation show considerably excellent performance for the monitoring of the marine system.

A Design of Fuzzy Logic Controllers for High-Angle-of-Attack Flight Control of Aircraft Using Adaptive Evolutionary Algorithms (적응진화 알고리즘을 이용한 항공기의 고공격각 비행 제어를 위한 퍼지 제어기 설계)

  • Won, Taep-Hyun;Hwang, Gi-Hyun;Park, June-Ho;Lee, Man-Hyung
    • Journal of Institute of Control, Robotics and Systems
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    • v.6 no.11
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    • pp.995-1002
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    • 2000
  • In this paper, fuzzy logic controllers(FLC) are designed for control of flight. For tuning FLC, we used adaptive evolutionary algorithms(AEA) which uses a genetic algorithm(GA) and an evolution strategy (ES) in an adaptive manner in order to take merits of two different evolutionary computations. We used AEA to search for optimal settings of the membership functions shape and gains of the inputs and outputs of FLC. Finally, the proposed controller is applied to the high-angle-of-attack flight system for a supermaneuverable version of the f-18 aircraft and compares with other methods.

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Mixed reality system using adaptive dense disparity estimation (적응적 미세 변이추정기법을 이용한 스테레오 혼합 현실 시스템 구현)

  • 민동보;김한성;양기선;손광훈
    • Proceedings of the IEEK Conference
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    • 2003.11a
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    • pp.171-174
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    • 2003
  • In this paper, we propose the method of stereo images composition using adaptive dense disparity estimation. For the correct composition of stereo image and 3D virtual object, we need correct marker position and depth information. The existing algorithms use position information of markers in stereo images for calculating depth of calibration object. But this depth information may be wrong in case of inaccurate marker tracking. Moreover in occlusion region, we can't know depth of 3D object, so we can't composite stereo images and 3D virtual object. In these reasons, the proposed algorithm uses adaptive dense disparity estimation for calculation of depth. The adaptive dense disparity estimation is the algorithm that use pixel-based disparity estimation and the search range is limited around calibration object.

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A study on an adaptive gait for a quadruped walking robot under external forces (외력 대처 기능을 갖는 사각 보행 로보트 적응 걸음새에 관한 연구)

  • ;;;;Zeungnam Bien
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.9
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    • pp.1-12
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    • 1996
  • In this paper, we propose an adaptive gait by which a quadruped walking robot can walk against external disturbances. This adaptive gait mechanism makes it possible for a quadruped walking robot to change its gait and accommodate external disturbances form various external environmental factors. Under the assumption that external disturbances can be converted to an external force acting on the body of a quadruped walking robot, we propose a new criterion for the stability margin of a waling robot by using an effective mass center based on the zero moment point under unknown external force. And for a solution of an adaptive gait against external disturbances, an method of altitude control and reflexive direction control is suggested. An algorithmic search method for an optimal stride of the quadruped mehtod, the gait stability margin of a quadruped walking robot is optimized in changing its direction at any instance for and after the reflexive direction control. To verify the efficiency of the proposed approach, some simulaton results are provided.

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Comparison of Adaptive Operators in Genetic Algorithms (유전알고리즘에서 적응적 연산자들의 비교연구)

  • Yun, Young-Su;Seo, Seoun-Lock
    • Journal of Intelligence and Information Systems
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    • v.8 no.2
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    • pp.189-203
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    • 2002
  • In this paper we compare the performances of adaptive operators in genetic algorithm. For the adaptive operators, the crossover and mutation operators of genetic algorithm are considered. One fuzzy logic controller is developed in this paper and two heuristics is presented from conventional works for constructing the operators. The fuzzy logic controller and two conventional heuristics adaptively regulate the rates of the operators during genetic search process. All the algorithms are tested and analyzed in numerical examples. Finally, the best algorithm is recommended.

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