• 제목/요약/키워드: Descent

검색결과 793건 처리시간 0.029초

Statistical Bias and Inflated Variance in the Genehunter Nonparametric Linkage Test Statistic

  • Song, Hae-Hiang;Choi, Eun-Kyeong
    • Communications for Statistical Applications and Methods
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    • 제16권2호
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    • pp.373-381
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    • 2009
  • Evidence of linkage is expressed as a decreasing trend of the squared trait difference of two siblings with increasing identical by descent scores. In contrast to successes in the application of a parametric approach of Haseman-Elston regression, notably low powers are demonstrated in the nonparametric linkage analysis methods for complex traits and diseases with sib-pairs data. We report that the Genehunter nonparametric linkage statistic is biased and furthermore the variance formula that they used is an inflated one, and this is one reason for a low performance. Thus, we propose bias-corrected nonparametric linkage statistics. Simulation studies comparing our proposed nonparametric test statistics versus the existing test statistics suggest that the bias-corrected new nonparametric test statistics are more powerful and attains efficiencies close to that of Haseman-Elston regression.

초기값의 최적 설정에 의한 최적화용 신경회로망의 성능개선 (Improving the Performances of the Neural Network for Optimization by Optimal Estimation of Initial States)

  • 조동현;최흥문
    • 전자공학회논문지B
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    • 제30B권8호
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    • pp.54-63
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    • 1993
  • This paper proposes a method for improving the performances of the neural network for optimization by an optimal estimation of initial states. The optimal initial state that leads to the global minimum is estimated by using the stochastic approximation. And then the update rule of Hopfield model, which is the high speed deterministic algorithm using the steepest descent rule, is applied to speed up the optimization. The proposed method has been applied to the tavelling salesman problems and an optimal task partition problems to evaluate the performances. The simulation results show that the convergence speed of the proposed method is higher than conventinal Hopfield model. Abe's method and Boltzmann machine with random initial neuron output setting, and the convergence rate to the global minimum is guaranteed with probability of 1. The proposed method gives better result as the problem size increases where it is more difficult for the randomized initial setting to give a good convergence.

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Sommerfeld 적분의 해석적 계산을 위한 최적 적분경로에 관한 연구 (A Study on the Optimum Integration Path for the Analytic Evaluation of the Sommerfeld Integrals)

  • 이영순;김의중;고지환;조영기
    • 한국전자파학회:학술대회논문집
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    • 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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    • pp.64-68
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    • 2003
  • For the purpose of the efficient derivation of the closed-form Green's functions by which MoM matrix elements can be analytically evaluated, the optimum approximation path which is deformed from the Sommerfeld integration path on the complex $k_{\rho}$-plane is proposed based upon the steepest descent method and three level approximation procedure.

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자기학습 퍼지제어기를 사용한 하이브리드 제어기 설계 (A Design of Hybrid Controller Using Self-Learning Fuzzy Controller)

  • 양혜원;이호형
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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    • pp.207-209
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    • 1995
  • The PID controller is widely used due to its fast response and robustness. But its performance is not so good compared with modem controllers such as adaptive, robust, fuzzy, neural controller. Therefore, it is natural to replace PID controller by modem controllers. But, the problem is that modem controller can not be easily applied to the real time process. Hence, this paper proposes such a structure that PID controller and Self-Learning Fuzzy Controller(SLFC) are in parallel with each other. The parameter of SLFC will be updated by gradient descent method using neuro - identifier. The usefulness of this hybrid controller will be proved by simulation results.

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보완 라그랑지안 승수 기법을 이용한 연계전력시장 청산 (Interregional Market Coordination Using a Distributed Augmented Lagrangian Algorithm)

  • 문국현;김지희;주성관
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.532-533
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    • 2008
  • 연계지역 전력시장 간의 에너지 거래는 전체 전력시장의 사회적 편익을 향상시키기 위해 이루어진다. 기존의 연계지역 전력시장 간시장 최적화 문제를 다루는 중앙처리 접근방식은 경쟁적 전력시장 환경하에서 적합한 모델이 아니다. 본 논문은 연계지역 전력시장 문제를 다루기 위해 보완 라그랑지안 승수 기법(Augmented Lagrangian Relaxation) 기반의 분산처리 최적화 방법을 제시한다. Block Coordinate Descent(BCD) 분산처리 기법이 보완 라그랑지안 승수의 최적화 문제를 분리하기 위해 적용된다. 연계시장 모델을 구현한 사례연구를 통해 제시된 알고리즘의 효용성을 입증한다.

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천연 기능성 소재 혼합물이 Streptozotocin 유발 제1형 당뇨 쥐의 혈당 강하 효과(I) (Effect of Natural Functional Mixture on the Descent of BloodGlucose Level in Streptozotocin-Induced Diabetic(type I) Rats(I))

  • 이수진
    • 한국조리학회지
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    • 제13권3호
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    • pp.199-206
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    • 2007
  • Hypoglycemic efficacy of natural functional mixture(FM) and level of the diabete related hormones in streptozotocin(STZ)-induced diabetic rats were investigated. Male Sprague-Dawley rats were divided into three groups (normal, diabetic fed diets with/without FM). Supplement of FM did not affect the body weight and feed intake of STZ-induced diabetic rats. The increase in the weight of liver of STZ-induced diabetic rats was weakened by supplement of FM, whereas the weight of kidney and heart was not affected. Blood glucose level was slightly, and glucose tolerance of post-feeding was significantly improved by functional mixture. The mixture significantly reduced the elevated HbA1C level of diabetic rats by 15%, and it increased the level of insulin and C-peptide in blood and decreased glucagon level. Therefore, we conclude that FM in this study has a potency of prevention and treatment of diabetes mellitus.

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Current Status of Quantitative Trait Locus Mapping in Livestock Species - Review -

  • Kim, Jong-Joo;Park, Young I.
    • Asian-Australasian Journal of Animal Sciences
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    • 제14권4호
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    • pp.587-596
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    • 2001
  • In the last decade, rapid developments in molecular biotechnology and of genomic tools have enabled the creation of dense linkage maps across whole genomes of human, plant and animals. Successful development and implementation of interval mapping methodologies have allowed detection of the quantitative trait loci (QTL) responsible for economically important traits in experimental and commercial livestock populations. The candidate gene approach can be used in any general population with the availability of a large resource of candidate genes from the human or rodent genomes using comparative maps, and the validated candidate genes can be directly applied to commercial breeds. For the QTL detected from primary genome scans, two incipient fine mapping approaches are applied by generating new recombinants over several generations or utilizing historical recombinants with identity-by-descent (IBD) and linkage disequilibrium (LD) mapping. The high resolution definition of QTL position from fine mapping will allow the more efficient implementation of breeding programs such as marker-assisted selection (MAS) or marker-assisted introgression (MAI), and will provide a route toward cloning the QTL.

Crack Identification Using Neuro-Fuzzy-Evolutionary Technique

  • Shim, Mun-Bo;Suh, Myung-Won
    • Journal of Mechanical Science and Technology
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    • 제16권4호
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    • pp.454-467
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    • 2002
  • It has been established that a crack has an important effect on the dynamic behavior of a structure. This effect depends mainly on the location and depth of the crack. Toidentifythelocation and depth of a crack in a structure, a method is presented in this paper which uses neuro-fuzzy-evolutionary technique, that is, Adaptive-Network-based Fuzzy Inference System (ANFIS) solved via hybrid learning algorithm (the back-propagation gradient descent and the least-squares method) and Continuous Evolutionary Algorithms (CEAs) solving sir ale objective optimization problems with a continuous function and continuous search space efficiently are unified. With this ANFIS and CEAs, it is possible to formulate the inverse problem. ANFIS is used to obtain the input(the location and depth of a crack) - output(the structural Eigenfrequencies) relation of the structural system. CEAs are used to identify the crack location and depth by minimizing the difference from the measured frequencies. We have tried this new idea on beam structures and the results are promising.

메타모델 기반 다단계 최적설계에 대한 순차적 알고리듬 (A Sequential Algorithm for Metamodel-Based Multilevel Optimization)

  • 김강민;백석흠;홍순혁;조석수;주원식
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회A
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    • pp.1198-1203
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    • 2008
  • An efficient sequential optimization approach for metamodel was presented by Choi et al [6]. This paper describes a new approach of the multilevel optimization method studied in Refs. [5] and [21-25]. The basic idea is concerned with multilevel iterative methods which combine a descent scheme with a hierarchy of auxiliary problems in lower dimensional subspaces. After fitting a metamodel based on an initial space filling design, this model is sequentially refined by the expected improvement criterion. The advantages of the method are that it does not require optimum sensitivities, nonlinear equality constraints are not needed, and the method is relatively easy to understand and use. As a check on effectiveness, the proposed method is applied to a classical cantilever beam.

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센서 정보를 활용한 스마트폰 모션 인식 (Motion Recognition of Smartphone using Sensor Data)

  • 이용철;이칠우
    • 한국멀티미디어학회논문지
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    • 제17권12호
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    • pp.1437-1445
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    • 2014
  • A smartphone has very limited input methods regardless of its various functions. In this respect, it is one alternative that sensor motion recognition can make intuitive and various user interface. In this paper, we recognize user's motion using acceleration sensor, magnetic field sensor, and gyro sensor in smartphone. We try to reduce sensing error by gradient descent algorithm because in single sensor it is hard to obtain correct data. And we apply vector quantization by conversion of rotation displacement to spherical coordinate system for elevated recognition rate and recognition of small motion. After vector quantization process, we recognize motion using HMM(Hidden Markov Model).