• Title/Summary/Keyword: Bayes' Theorem

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ON-LINE ESTIMATION PROCEDURES OF DIGITAL FILTER TYPE FOR REVERBERATION CHARACTERISTICS IN CLOSED ACOUSTIC SYSTEMS BASED ON NOISY OBSERVATION

  • Hiromitsu, Seijiro;Ohta, Mitsuo
    • Proceedings of the Acoustical Society of Korea Conference
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    • 1994.06a
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    • pp.680-685
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    • 1994
  • The acoustic phenomena in the actual sound systems involve a variety of compound problems. In this paper, the well-known Bayes' theorem is first employed and expanded into orthonormal and non-orthonomal series forms matched to the digital processing of lower and higher order statistical informations and the noisy observations. Proposed on-line algorithms of digital filter type are applied to the actual state estimation for a reverberation characteristics in a room under contamination of background noises.

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A Long-term Durability Prediction for RC Structures Exposed to Carbonation Using Probabilistic Approach (확률론적 기법을 이용한 탄산화 RC 구조물의 내구성 예측)

  • Jung, Hyun-Jun;Kim, Gyu-Seon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.5
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    • pp.119-127
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    • 2010
  • This paper provides a new approach for durability prediction of reinforced concrete structures exposed to carbonation. In this method, the prediction can be updated successively by a Bayes' theorem when additional data are available. The stochastic properties of model parameters are explicitly taken into account in the model. To simplify the procedure of the model, the probability of the durability limit is determined based on the samples obtained from the Latin Hypercube Sampling(LHS) technique. The new method may be very useful in design of important concrete structures and help to predict the remaining service life of existing concrete structures which have been monitored. For using the new method, in which the prior distribution is developed to represent the uncertainties of the carbonation velocity using data of concrete structures(3700 specimens) in Korea and the likelihood function is used to monitor in-situ data. The posterior distribution is obtained by combining a prior distribution and a likelihood function. Efficiency of the LHS technique for simulation was confirmed through a comparison between the LHS and the Monte Calro Simulation(MCS) technique.

A Study on the Quantitative Determination of Failure Effect Probability for Criticality Analysis on System (시스템의 치명도 분석을 위한 고장영향확률 정량화 방안 연구)

  • Lee, Myeong-seok;Choi, Seong-Dae;Hur, Jang-wook
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.18 no.8
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    • pp.31-37
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    • 2019
  • The inter-development of FMECA is very important to assess the effect of potential failures during system operation on mission, safety and performance. Among these, criticality analysis is a core task that identifies items with high risk and selects the analyzed objects as the key management targets and reflects their effects to the design optimization. In this paper, we analyze the theory related to criticality analysis following US military standard, and propose a method to quantify the failure effect probability for objective criticality analysis. The criticality analysis according to the US military standard depends on the subjective judgment of the failure probability. The methodology for quantifying the failure effect probability is presented by using the reliability theory and the Bayes theorem. The failure rate is calculated by applying the method to quantify failure effect probability.

Hypotheses testing of Bayes' theorem for fuzzy prior parameters (퍼지 사전 모수에 관한 베이지안 가설검정)

  • Kang Man-Ki;Chio Gue-Tak
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2005.11a
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    • pp.205-208
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    • 2005
  • We have fuzzy hypotheses testing from Bayesian statistics with ideas from fuzzy sets theory to generalize Bayesian methods both for samples of fuzzy data and for prior distributions with non-precise parameters. Appling the principle of agreement index, the posterior odds ratio in the favor of hypotheses $H_0$ is equal to product of the fuzzy odds ratio and the fuzzy likelihood ratio. If the Posterior odds ratio exceeds the grade judgement, we accept the hypothesis $H_0$ for the degree.

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Understanding Bayesian Statistics

  • Jeong, Yun-Sik
    • Proceedings of the Korean Statistical Society Conference
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    • 2002.11a
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    • pp.61-68
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    • 2002
  • 통계학은 불확실성(uncertainty)에 대한 연구이다. 베이지안 통계 방법은 불확실성 아래서 통계 추론과 의사 결정 모두를 위한 완전한(complete) 패러다임을 제공한다. 베이지안 방법론은 합리적인 초기 정보와 결합하는 것을 가능하게 만들고, 전통적인 통계적 방법론에 의하여 직면하는 많은 어려움들을 풀 수 있는 coherent 방법론을 제공하면서 엄격한 수학적 기본에 근거하고 있다. 베이지안 패러다임은 일반적인 용어로써 확률이란 단어의 사용을 가장 잘 어울리게 하는 불확실성의 조건부 측도(conditional measure of uncertainty)로써 확률의 해석에 근거한다. 관심있는 것에 대한 통계적 추론은 증거의 관점에서 그 값에 대한 불확실성의 변형으로써 묘사되며, 베이즈 정리(Bayes' theorem)는 이러한 변형이 어떻게 만들어지는 가를 자세히 설명할 수 있다. 베이지안 방법들은 전통적인 통계적 방법론에 접근할 없는 복잡하고, 다양한 구조적 문제들에 응용할 수 있다.

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AzTEC Submillimeter Survey of Galaxies

  • Kim, Ki-Hun;Kim, Sung-Eun;AzTEC team, AzTEC team
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.38.1-38.1
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    • 2010
  • We present the results of the survey for submillimeter galaxies in the MS0451 (04h 54m 10.8s, -03d 00m 57.0s) at z = 0.55 and PKS1138-262 (11h 40m 48.25s, -26d 29m 10.1s) at z = 2.16 with the 1.1mm bolometer array AzTEC at the James Clerk Maxwell Telescope. The samples were centered on a prominent large-scale structure overdensity. Submillimeter galaxies seem to be starburst galaxies at high redshift ($z\;\geq\;1$) with high starformation rates ($\sim1000M\odot\;yr^{-1}$) or active galactic nuclei (AGN). We have obtained AzTEC images using the AzTEC data reduction pipeline with the IDL language. Through a bayes' theorem, we determined the extragalaxy catalogue, containing the false-detection rate, completeness, flux deboosting correction, and the source positional uncertainty in this region. We compared the catalogue with HST, DSS, 2MASS observations.

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EVALUATION OF DIAGNOSTIC TESTS WITH MULTIPLE DIAGNOSTIC CATEGORIES

  • Birkett N.J.
    • 대한예방의학회:학술대회논문집
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    • 1994.02b
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    • pp.154-157
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    • 1994
  • The evaluation of diagnostic tests attempts to obtain one or more statistical parameters which can indicate the intrinsic diagnostic utility of a test. Sensitivity. specificity and predictive value are not appropriate for this use. The likelihood ratio has been proposed as a useful measure when using a test to diagnose one of two disease states (e.g. disease present or absent). In this paper, we generalize the likelihood ratio concept to a situation in which the goal is to diagnose one of several non-overlapping disease states. A formula is derived to determine the post-test probability of a specific disease state. The post-test odds are shown to be related to the pre-test odds of a disease and to the usual likelihood ratios derived from considering the diagnosis between the target diagnosis and each alternate in turn. Hence, likelihood ratios derived from comparing pairs of diseases can be used to determine test utility in a multiple disease diagnostic situation.

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Review on the Application of Statistical Methods to Maritime Traffic Safety Assessment

  • Gong, In-Young
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.35-40
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    • 2006
  • For the maritime traffic safety assessment of vessels navigating in harbor or fairway, simulation techniques by using shiphandling simulator system have been traditionally used. When designing the simulation experiments and when analyzing the simulation results, however, there has been a little systematic method. Ship-handling simulations can be regarded as a kind of statistical experiment by using ship-handling simulator system, which means that shiphandling simulation conditions should be designed statistically and that the simulation results should be statistically analyzed as well. For the safe and economic design of harbor and fairway, reasonable decisions based upon the scientific analysis of shiphandling simulation results are indispensable. In this paper, various statistical methods, such as Bayes theorem, statistical hypothesis testing, and probability distributions, are reviewed with a view to application to maritime traffic safety assessment. It is expected that more reasonable decisions on harbor and fairway design can be made from shiphandlers' view point by using statistical methods.

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A Study on Evaluation of Optimal Replacement Period by Reliability Prediction for the Door Control Relay of EMU (전동차 출입문제어 계전기의 신뢰도예측을 통한 적정 교체주기 연구)

  • Han, Jaehyun;Kim, JongWoon;Koo, JeongSeo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.28 no.7
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    • pp.34-40
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    • 2014
  • In this paper, we want to know the optimal replacement cycle(time) for this study was performed. The optimal preventive replacement age can be fond by finding the value of time that minimizes the cost function(model of Barlow and Jardine). In addition, The reliability of the relay according to the service environment were studied. The use of the exchange relay period is longer, and maintenance cost rate(per hour) may increase, and also the reliability may cause a decline. In addition, considering the preventive maintenance and purchase order, a representative relay(RAX-L440-A type) life was calculated.

Recognition of Korean Vowels using Bayesian Classification with Mouth Shape (베이지안 분류 기반의 입 모양을 이용한 한글 모음 인식 시스템)

  • Kim, Seong-Woo;Cha, Kyung-Ae;Park, Se-Hyun
    • Journal of Korea Multimedia Society
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    • v.22 no.8
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    • pp.852-859
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    • 2019
  • With the development of IT technology and smart devices, various applications utilizing image information are being developed. In order to provide an intuitive interface for pronunciation recognition, there is a growing need for research on pronunciation recognition using mouth feature values. In this paper, we propose a system to distinguish Korean vowel pronunciations by detecting feature points of lips region in images and applying Bayesian based learning model. The proposed system implements the recognition system based on Bayes' theorem, so that it is possible to improve the accuracy of speech recognition by accumulating input data regardless of whether it is speaker independent or dependent on small amount of learning data. Experimental results show that it is possible to effectively distinguish Korean vowels as a result of applying probability based Bayesian classification using only visual information such as mouth shape features.