• Title/Summary/Keyword: Adaptive sampling

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Sensitivity Approach of Sequential Sampling Using Adaptive Distance Criterion (적응거리 조건을 이용한 순차적 실험계획의 민감도법)

  • Jung, Jae-Jun;Lee, Tae-Hee
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.9 s.240
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    • pp.1217-1224
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    • 2005
  • To improve the accuracy of a metamodel, additional sample points can be selected by using a specified criterion, which is often called sequential sampling approach. Sequential sampling approach requires small computational cost compared to one-stage optimal sampling. It is also capable of monitoring the process of metamodeling by means of identifying an important design region for approximation and further refining the fidelity in the region. However, the existing critertia such as mean squared error, entropy and maximin distance essentially depend on the distance between previous selected sample points. Therefore, although sufficient sample points are selected, these sequential sampling strategies cannot guarantee the accuracy of metamodel in the nearby optimum points. This is because criteria of the existing sequential sampling approaches are inefficient to approximate extremum and inflection points of original model. In this research, new sequential sampling approach using the sensitivity of metamodel is proposed to reflect the response. Various functions that can represent a variety of features of engineering problems are used to validate the sensitivity approach. In addition to both root mean squared error and maximum error, the error of metamodel at optimum points is tested to access the superiority of the proposed approach. That is, optimum solutions to minimization of metamodel obtained from the proposed approach are compared with those of true functions. For comparison, both mean squared error approach and maximin distance approach are also examined.

A Study on Adaptive Signal Processing of Digital Receiver for Adaptive Antenna System (어댑티브 안테나 시스템용 디지털 수신기의 적응신호처리에 관한 연구)

  • 민경식;박철근;고지원;임경우;이경학;최재훈
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
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    • 2002.11a
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    • pp.44-48
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    • 2002
  • This paper describes an adaptive signal processing of digital receiver with DDC(Digital Down Convertor), DDC is implemented by using NCO(Numerically Controlled Oscillator), digital low pass filter. for the passband sampling, we present the results of digital receiver simulation with DDC. We confirm that the low IP signal is converted to zero IF by DDC. DOA(Direction Of Arrival) estimation technique using MUSIC(Multiple SIgnal Classification) algorithm with high resolution is presented. We Cow that an accurate resolution of DOA depends on the input sampling number.

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Probability Constrained Search Range Determination for Fast Motion Estimation

  • Kang, Hyun-Soo;Lee, Si-Woong;Hosseini, Hamid Gholam
    • ETRI Journal
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    • v.34 no.3
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    • pp.369-378
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    • 2012
  • In this paper, we propose new adaptive search range motion estimation methods where the search ranges are constrained by the probabilities of motion vector differences and a search point sampling technique is applied to the constrained search ranges. Our new methods are based on our previous work, in which the search ranges were analytically determined by the probabilities. Since the proposed adaptive search range motion estimation methods effectively restrict the search ranges instead of search point sampling patterns, they provide a very flexible and hardware-friendly approach in motion estimation. The proposed methods were evaluated and tested with JM16.2 of the H.264/AVC video coding standard. Experiment results exhibit that with negligible degradation in PSNR, the proposed methods considerably reduce the computational complexity in comparison with the conventional methods. In particular, the combined method provides performance similar to that of the hybrid unsymmetrical-cross multi-hexagon-grid search method and outstanding merits in hardware implementation.

An Adaptive Optimization Algorithm Based on Kriging Interpolation with Spherical Model and its Application to Optimal Design of Switched Reluctance Motor

  • Xia, Bin;Ren, Ziyan;Zhang, Yanli;Koh, Chang-Seop
    • Journal of Electrical Engineering and Technology
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    • v.9 no.5
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    • pp.1544-1550
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    • 2014
  • In this paper, an adaptive optimization strategy utilizing Kriging model and genetic algorithm is proposed for the optimal design of electromagnetic devices. The ordinary Kriging assisted by the spherical covariance model is used to construct surrogate models. In order to improve the computational efficiency, the adaptive uniform sampling strategy is applied to generate sampling points in design space. Through several iterations and gradual refinement process, the global optimal point can be found by genetic algorithm. The proposed algorithm is validated by application to the optimal design of a switched reluctance motor, where the stator pole face and shape of pole shoe attached to the lateral face of the rotor pole are optimized to reduce the torque ripple.

Objective Bayesian Estimation of Two-Parameter Pareto Distribution (2-모수 파레토분포의 객관적 베이지안 추정)

  • Son, Young Sook
    • The Korean Journal of Applied Statistics
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    • v.26 no.5
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    • pp.713-723
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    • 2013
  • An objective Bayesian estimation procedure of the two-parameter Pareto distribution is presented under the reference prior and the noninformative prior. Bayesian estimators are obtained by Gibbs sampling. The steps to generate parameters in the Gibbs sampler are from the shape parameter of the gamma distribution and then the scale parameter by the adaptive rejection sampling algorism. A numerical study shows that the proposed objective Bayesian estimation outperforms other estimations in simulated bias and mean squared error.

Microcomputer-aided design for a digital adaptive control system (디지탈 적응제어 시스템 해석을 위한 마이크로컴퓨터 지원설계)

  • 주해호;조충래
    • 제어로봇시스템학회:학술대회논문집
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    • 1988.10a
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    • pp.540-545
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    • 1988
  • In this study a microcomputer-aided design program has been developed to design and analysis for the digital adaptive control system. DACS(Digital Adaptive Control System) program has been written in GWBASIC language which is suitable for IBM-PC compatible. The dynamics of each element was modulized and described by linear difference equations. By the aid of this program, sampling time, the number of bits of A/D and D/A converter and the stability for the digital adaptive control system can be determined. In order to estimate the system parameters an on-line identification and a regression analysis method are utilized. The simulation results have been well agreed with the experiments. To demonstrate the utility of this program, an adaptive control system has been designed for air-heating system.

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A Study of Optimization of Integral Time and Sampling Time on Predictive Model Controller (예측 모델 제어기 설계에서의 예측 시간의 최적화 및 예측 샘플링 시간의 최적화에 대한 연구)

  • Wang, Hyun-Min;Woo, Kwang-Joon;Huh, Kyung-Moo
    • Proceedings of the KIEE Conference
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    • 2008.10b
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    • pp.421-424
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    • 2008
  • The real time modeling of dynamic system on adaptive control system is very important for flying control system(FCS). Using traditional method, it is required much calculation load for integral/differential at control system. Therefore, It is very important theme of study in these days to find algorithms for integration/differential at FCS. These algorithms for integral/differential influence strongly stability/reliability to control flying object. In this paper, we present optimal predictive sampling time for reduce calculation load at FCS and optimal predictive time on general cost function by applying adaptive control method.

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Equivalent Circuit Model of RF passive components based on its simulated frequency response data (EM Solver 의 주파수 응답 데이터를 이용한 RF 수동 소자의 등가회로 모델링에 관한 연구)

  • Oh, Sang-Bae;Ko, Jae-Hyeong;Han, Hyeong-Seok;Kim, Hyeong-Seok
    • 한국정보통신설비학회:학술대회논문집
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    • 2007.08a
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    • pp.27-30
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    • 2007
  • This paper deals with an equivalent circuit model for RF passive components. Rational functions are obtained from the frequency responses of EM simulation by using Foster canonical partial fraction expressions. The Vector Fitting(VF) and the Adaptive Frequency Sampling(AFS) scheme are also implemented to obtain the rational functions. A passivity enforcement algorithm is applied to ensure the stability of the equivalent circuit model. In order to verify the schemes, S parameters of the equivalent circuit model is compared to those of EM simulation in case of the microstrip line structure with 3 slots in ground.

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An Improved Distributed Equivalent Circuit Modeling for RF Components by Real-Coefficient AFS Technique

  • Kim, Koon-Tae;Ko, Jae-Hyeong;Paek, Hyun;Kahng, Sung-Tek;Kim, Hyeong-Seok
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.408-413
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    • 2011
  • In this paper, a real-coefficient approach to Adaptive Frequency Sampling (AFS) technique is developed for efficient equivalent circuit modeling of RF components. This proposed method is advantageous than the vector fitting technique and the conventional AFS method in terms of fewer samples leading to a lower order of a rational function on a given data and to a direct conversion to an equivalent circuit for PSPICE(Personal Simulation Program with Integrated Circuit Emphsis) simulation, respectively. To validate the proposed method, the distributed equivalent circuit of a presented multi-layered RF low-pass filter is obtained using the proposed real-coefficient AFS, and then comparisons with EM simulation and circuit simulation for the device under consideration are achieved.

A Robust Background Subtraction Algorithm for Dynamic Scenes based on Multiple Interval Pixel Sampling (다중 구간 샘플링에 기반한 동적 배경 영상에 강건한 배경 제거 알고리즘)

  • Lee, Haeng-Ki;Choi, Young Kyu
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.2
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    • pp.31-36
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    • 2020
  • Most of the background subtraction algorithms show good performance in static scenes. In the case of dynamic scenes, they frequently cause false alarm to "temporal clutter", a repetitive motion within a certain area. In this paper, we propose a robust technique for the multiple interval pixel sampling (MIS) algorithm to handle highly dynamic scenes. An adaptive threshold scheme is used to suppress false alarms in low-confidence regions. We also utilize multiple background models in the foreground segmentation process to handle repetitive background movements. Experimental results revealed that our approach works well in handling various temporal clutters.