• Title/Summary/Keyword: conditional probability model

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Density estimation of summer extreme temperature over South Korea using mixtures of conditional autoregressive species sampling model (혼합 조건부 종추출모형을 이용한 여름철 한국지역 극한기온의 위치별 밀도함수 추정)

  • Jo, Seongil;Lee, Jaeyong
    • Journal of the Korean Data and Information Science Society
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    • v.27 no.5
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    • pp.1155-1168
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    • 2016
  • This paper considers a probability density estimation problem of climate values. In particular, we focus on estimating probability densities of summer extreme temperature over South Korea. It is known that the probability density of climate values at one location is similar to those at near by locations and one doesn't follow well known parametric distributions. To accommodate these properties, we use a mixture of conditional autoregressive species sampling model, which is a nonparametric Bayesian model with a spatial dependency. We apply the model to a dataset consisting of summer maximum temperature and minimum temperature over South Korea. The dataset is obtained from University of East Anglia.

Analysis of Nested Case-Control Study Designs: Revisiting the Inverse Probability Weighting Method

  • Kim, Ryung S.
    • Communications for Statistical Applications and Methods
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    • v.20 no.6
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    • pp.455-466
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    • 2013
  • In nested case-control studies, the most common way to make inference under a proportional hazards model is the conditional logistic approach of Thomas (1977). Inclusion probability methods are more efficient than the conditional logistic approach of Thomas; however, the epidemiology research community has not accepted the methods as a replacement of the Thomas' method. This paper promotes the inverse probability weighting method originally proposed by Samuelsen (1997) in combination with an approximate jackknife standard error that can be easily computed using existing software. Simulation studies demonstrate that this approach yields valid type 1 errors and greater powers than the conditional logistic approach in nested case-control designs across various sample sizes and magnitudes of the hazard ratios. A generalization of the method is also made to incorporate additional matching and the stratified Cox model. The proposed method is illustrated with data from a cohort of children with Wilm's tumor to study the association between histological signatures and relapses.

Electronic Commerce Navigation Agent Model using Conditional Probability and Fuzzy Number (조건부 확률과 퍼지수를 이용한 전자상거래 검색 에이전트 모델)

  • 김명순;원성현;정환묵
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2001.05a
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    • pp.219-223
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    • 2001
  • In this paper, we proposed the intelligent navigation agent model for successive electronic commerce management. For allowing intelligence, we used conditional probability and trapezoidal fuzzy number. Our goal of study is make an intelligent automatic navigation agent model.

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Quantitative Frameworks for Multivalent Macromolecular Interactions in Biological Linear Lattice Systems

  • Choi, Jaejun;Kim, Ryeonghyeon;Koh, Junseock
    • Molecules and Cells
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    • v.45 no.7
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    • pp.444-453
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    • 2022
  • Multivalent macromolecular interactions underlie dynamic regulation of diverse biological processes in ever-changing cellular states. These interactions often involve binding of multiple proteins to a linear lattice including intrinsically disordered proteins and the chromosomal DNA with many repeating recognition motifs. Quantitative understanding of such multivalent interactions on a linear lattice is crucial for exploring their unique regulatory potentials in the cellular processes. In this review, the distinctive molecular features of the linear lattice system are first discussed with a particular focus on the overlapping nature of potential protein binding sites within a lattice. Then, we introduce two general quantitative frameworks, combinatorial and conditional probability models, dealing with the overlap problem and relating the binding parameters to the experimentally measurable properties of the linear lattice-protein interactions. To this end, we present two specific examples where the quantitative models have been applied and further extended to provide biological insights into specific cellular processes. In the first case, the conditional probability model was extended to highlight the significant impact of nonspecific binding of transcription factors to the chromosomal DNA on gene-specific transcriptional activities. The second case presents the recently developed combinatorial models to unravel the complex organization of target protein binding sites within an intrinsically disordered region (IDR) of a nucleoporin. In particular, these models have suggested a unique function of IDRs as a molecular switch coupling distinct cellular processes. The quantitative models reviewed here are envisioned to further advance for dissection and functional studies of more complex systems including phase-separated biomolecular condensates.

Real-Time Motion Estimation Algorithm for Mobile Surveillance Robot (모바일 감시 로봇을 위한 실시간 움직임 추정 알고리즘)

  • Han, Cheol-Hoon;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.19 no.3
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    • pp.311-316
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    • 2009
  • This paper presents the motion estimation algorithm on real-time for mobile surveillance robot using particle filter. the particle filter that based on the monte carlo's sampling method, use bayesian conditional probability model which having prior distribution probability and posterior distribution probability. However, the initial probability density was set to define randomly in the most of particle filter. In this paper, we find first the initial probability density using Sum of Absolute Difference(SAD). and we applied it in the partical filter. In result, more robust real-time estimation and tracking system on the randomly moving object was realized in the mobile surveillance robot environments.

Probability-Based Context-Generation Model with Situation Propagation Network (상황 전파 네트워크를 이용한 확률기반 상황생성 모델)

  • Cheon, Seong-Pyo;Kim, Sung-Shin
    • The Journal of Korea Robotics Society
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    • v.4 no.1
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    • pp.56-61
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    • 2009
  • A probability-based data generation is a typical context-generation method that is a not only simple and strong data generation method but also easy to update generation conditions. However, the probability-based context-generation method has been found its natural-born ambiguousness and confliction problems in generated context data. In order to compensate for the disadvantages of the probabilistic random data generation method, a situation propagation network is proposed in this paper. The situation propagating network is designed to update parameters of probability functions are included in probability-based data generation model. The proposed probability-based context-generation model generates two kinds of contexts: one is related to independent contexts, and the other is related to conditional contexts. The results of the proposed model are compared with the results of the probabilitybased model with respect to performance, reduction of ambiguity, and confliction.

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A Study on Electronic Commerce Navigation Agent Model Using Fuzzy-Conditional Probability (퍼지-조건부확률을 이용한 전자상거래 검색 에이전트 모델에 관한 연구)

  • 김명순
    • Journal of the Korea Society of Computer and Information
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    • v.9 no.2
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    • pp.1-6
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    • 2004
  • In this paper, we proposed the intelligent navigation agent model for successive electronic commerce management. For allowing intelligence, we used fuzzy conditional probability and trapezoidal. we proposed the model that can Process the vague keywords effectively. Through the this, we verified that we can get the more appropriate navigation result than any other crisp retrieval keywords condition. Our goal of study is make an intelligent automatic navigation agent model.

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Forecasting volatility via conditional autoregressive value at risk model based on support vector quantile regression

  • Shim, Joo-Yong;Hwang, Chang-Ha
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.3
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    • pp.589-596
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    • 2011
  • The conditional autoregressive value at risk (CAViaR) model is useful for risk management, which does not require the assumption that the conditional distribution does not vary over time but the volatility does. But it does not provide volatility forecasts, which are needed for several important applications such as option pricing and portfolio management. For a variety of probability distributions, it is known that there is a constant relationship between the standard deviation and the distance between symmetric quantiles in the tails of the distribution. This inspires us to use a support vector quantile regression (SVQR) for volatility forecasts with the distance between CAViaR forecasts of symmetric quantiles. Simulated example and real example are provided to indicate the usefulness of proposed forecasting method for volatility.

Numerical Study on Methane/Air Turbulent Jet Diffusion Flames Near-Extinction Using Conditional Moment Closure Model (CMC model에 의한 near-extinction methane/air turbulent jet diffusion flame의 수치적 모사)

  • Kang, Seung-Tak;Kim, Seung-Hyun;Huh, Kang-Yul
    • 한국연소학회:학술대회논문집
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    • 2002.11a
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    • pp.11-17
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    • 2002
  • The first-order conditional moment closure (CMC) model is applied to $CH_4$/Air turbulent jet diffusion flames(Sandia Flame D, E and F). The flow and mixing fields are calculated by fast chemistry assumption and a beta function pdf for mixture fraction. Reacting scalar fields are calculated by elliptic CMC formulation. The results for Flame D show reasonable agreement with the measured conditional mean temperature and mass fractions of major species, although with discrepancy on the fuel rich side. The discrepancy tends to increase as the level of local extinction increases. Second-order CMC may be needed for better prediction of these near-extinction flames.

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Identification of flexible vehicle parameters on bridge using particle filter method

  • Talukdar, S.;Lalthlamuana, R.
    • Structural Engineering and Mechanics
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    • v.57 no.1
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    • pp.21-43
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    • 2016
  • A conditional probability based approach known as Particle Filter Method (PFM) is a powerful tool for system parameter identification. In this paper, PFM has been applied to identify the vehicle parameters based on response statistics of the bridge. The flexibility of vehicle model has been considered in the formulation of bridge-vehicle interaction dynamics. The random unevenness of bridge has been idealized as non homogeneous random process in space. The simulated response has been contaminated with artificial noise to reflect the field condition. The performance of the identification system has been examined for various measurement location, vehicle velocity, bridge surface roughness factor, noise level and assumption of prior probability density. Identified vehicle parameters are found reasonably accurate and reconstructed interactive force time history with identified parameters closely matches with the simulated results. The study also reveals that crude assumption of prior probability density function does not end up with an incorrect estimate of parameters except requiring longer time for the iterative process to converge.