• Title/Summary/Keyword: Metropolis

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Bayesian Procedure for the Multiple Change Point Analysis of Fraction Nonconforming (부적합률의 다중변화점분석을 위한 베이지안절차)

  • Kim, Kyung-Sook;Kim, Hee-Jeong;Park, Jeong-Soo;Son, Young-Sook
    • Proceedings of the Korean Society for Quality Management Conference
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    • 2006.04a
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    • pp.319-324
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    • 2006
  • In this paper, we propose Bayesian procedure for the multiple change points analysis in a sequence of fractions nonconforming. We first compute the Bayes factor for detecting the existence of no change, a single change or multiple changes. The Gibbs sampler with the Metropolis-Hastings subchain is run to estimate parameters of the change point model, once the number of change points is identified. Finally, we apply the results developed in this paper to both a real and simulated data.

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Evaluation of the Excess Free Energy for Two-Center-Lennard-Jones Liquids Using the Vent Effective Acceptance Ratio

  • Hong, Seong Do
    • Bulletin of the Korean Chemical Society
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    • v.21 no.7
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    • pp.697-700
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    • 2000
  • A method of calculating the excess Helmholtz free energy from the average of the bent effective acceptance ratio for two-center-Lennard-Jones liquids has been presented. The bent effective acceptance ratio has been newly composed from the acceptan ce ratio for the potential energy difference between a configuration in the Metropolis Monte Carlo procedure and random virtual configuration generated by the separate parallel Monte Carlo procedure and the Boltzmann factor for half the potential energy difference. The excess Helmholtz free energy was calculated directly from the average of the bent effective acceptance ratio through a single Metropolis Monte Carlo run. Because the separate parallel Monte Carlo procedure was used, this method can be applied to molecular dynamics simulations. For two-center-Lennard-Jones liquids, the average of the bent effective acceptance ratio gave better results than use of the modified effective acceptance ratio in the previous work.

An evolutionary approach for structural reliability

  • Garakaninezhad, Alireza;Bastami, Morteza
    • Structural Engineering and Mechanics
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    • v.71 no.4
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    • pp.329-339
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    • 2019
  • Assessment of failure probability, especially for a complex structure, requires a considerable number of calls to the numerical model. Reliability methods have been developed to decrease the computational time. In this approach, the original numerical model is replaced by a surrogate model which is usually explicit and much faster to evaluate. The current paper proposed an efficient reliability method based on Monte Carlo simulation (MCS) and multi-gene genetic programming (MGGP) as a robust variant of genetic programming (GP). GP has been applied in different fields; however, its application to structural reliability has not been tested. The current study investigated the performance of MGGP as a surrogate model in structural reliability problems and compares it with other surrogate models. An adaptive Metropolis algorithm is utilized to obtain the training data with which to build the MGGP model. The failure probability is estimated by combining MCS and MGGP. The efficiency and accuracy of the proposed method were investigated with the help of five numerical examples.

Fast Simulated Annealing with Greedy Selection (Greedy 선택방법을 적용한 빠른 모의 담금질 방법)

  • Lee, Chung-Yeol;Lee, Sun-Young;Lee, Soo-Min;Lee, Jong-Seok;Park, Cheol-Hoon
    • The KIPS Transactions:PartB
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    • v.14B no.7
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    • pp.541-548
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    • 2007
  • Due to the mathematical convergence property, Simulated Annealing (SA) has been one of the most popular optimization algorithms. However, because of its problem of slow convergence in the practical use, many variations of SA like Fast SA (FSA) have been developed for faster convergence. In this paper, we propose and prove that Greedy SA (GSA) also finds the global optimum in probability in the continuous space optimization problems. Because the greedy selection does not allow the cost to become worse, GSA is expected to have faster convergence than the conventional FSA that uses Metropolis selection. In the computer simulation, the proposed method is shown to have as good performance as FSA with Metropolis selection in the viewpoints of the convergence speed and the quality of the found solution. Furthermore, the greedy selection does not concern the cost value itself but uses only dominance of the costs of solutions, which makes GSA invariant to the problem scaling.

An Analysis of Work-Related Musculoskeletal Disorders Among Butchers in Kano Metropolis, Nigeria

  • Kaka, Bashir;Idowu, Opeyemi A.;Fawole, Henrietta O.;Adeniyi, Ade F.;Ogwumike, Omoyemi O.;Toryila, Mark T.
    • Safety and Health at Work
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    • v.7 no.3
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    • pp.218-224
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    • 2016
  • Background: Butchering is often associated with high rates of work-related musculoskeletal disorders (WRMSDs). However, published work on the prevalence of WRMSDs among butchers in Nigeria is scarce. This is important because meat processing practices differ across geographical and cultural locations. This study was therefore aimed at analyzing WRMSDs among butchers in Kano metropolis. Methods: Sociodemographic and work-settings information was obtained from 102 male cattle butchers (age, $37.49{\pm}11.68years$) through survey. Information on the prevalence and pattern of musculoskeletal disorders was obtained from the respondents using the Standardized Nordic Questionnaire. Additional information on health seeking practices was also obtained using a pro forma. Associations between the prevalence of WRMSDs and each of the sociodemographic data and work settings were explored using Chi-square analysis. The level of significance was set at p < 0.05. Results: The 12-month and point prevalence rates of WRMSDs among butchers in this study were 88.2% and 74.5%, respectively. Whereas lower back complaints (66.7%) were the overall and lower body quadrant's most commonly reported WRMSDs among the butchers surveyed, wrist/hand complaints were the leading upper quadrant's (45.1%) most commonly reported WRMSDs among the respondents. There were significant associations between age and majority of WRMSDs in the body regions. Only 23.3% of the 90 individuals who had WRMSD visited the hospital to seek redress for their WRMSD. Conclusion: The prevalence of WRMSDs is high among butchers in Kano Metropolis. Few individuals with WRMSD utilize healthcare facilities. Age is a major risk factor in this setting.

Comparative Appraisal of Sustainable Development in Korean Metropolis (우리나라 대도시의 지속가능발전성 비교평가)

  • Kim, Jai-Han
    • Journal of the Korean association of regional geographers
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    • v.13 no.3
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    • pp.235-253
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    • 2007
  • The paper has its focus on comparative appraisal of sustainable development in korean metropolises. In reference to OECD, UNCSD, PCSD and BBR indicator lists, somewhat transformed 14 themes and 42 quantitative indicators were chosen in economic, social and environmental sector. In next step, for the standardization of the indicators the own value of each Metropolis was relatively appraised based on the mean value of each indicator of the metropolises. If necessary, the indicator which has negative characteristics was transformed into positive scale so as to compare all of the indicators with same scale direction. As a result, it was found out that Seoul and Ulsan, highly concentrated in specific economic sector, reveals high level of sustainable development in economic sector but not in environmental sector. Kwangju is diametrically opposed to the former case. In contrast to the generally low level of sustainable development of Pusan, Taegu and Incheon, the metropolis Taejeon shows equally high level of sustainable development in 3 sectors.

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Lung Function of Grain Millers Exposed to Grain Dust and Diesel Exhaust in Two Food Markets in Ibadan Metropolis, Nigeria

  • Iyogun, Kemi;Lateef, Suraju A.;Ana, Godson R.E.E.
    • Safety and Health at Work
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    • v.10 no.1
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    • pp.47-53
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    • 2019
  • Background: Despite growing concern over occupational exposure to particulate matter (PM) such as grain dust and diesel exhaust, information about the exposure level and health implications among workers in small-scale milling enterprises in developing countries like Nigeria has not been adequately documented. The purpose of this study was to assess the level of exposure to grain dust and diesel exhaust and effect on lung function among grain millers in food markets in Ibadan metropolis, Nigeria. Methods: The study adopted descriptive cross-sectional design with a comparative approach. Sixteen grain milling shops each were randomly selected from two major food markets in Ibadan metropolis for indoor $PM_{10}$ and $PM_{2.5}$ monitoring. Seventy-two respondents each were proportionately selected from grain millers and shop owners for forced expiratory volume in one second and peak expiratory flow rate tests. Results: The $PM_{2.5}$ concentrations for both market locations ranged between 1,269.3 and $651.7{\mu}g/m^3$, while $PM_{10}$ concentrations were between 1,048.2 and $818.1{\mu}g/m^3$. The recorded concentrations exceeded the World Health Organization guideline limit of $50{\mu}g/m^3$ and $25{\mu}g/m^3$ for $PM_{2.5}$ and $PM_{10}$, respectively. As compared with control group (2.1 L), significantly lower forced expiratory volume in one second value (1.61 L) was observed among the exposed group (p < 0.05). Likewise, significantly lower peak expiratory flow rate value (186.7 L/min) was recorded among the exposed group than the control group (269.51 L/min) (p < 0.05). Conclusion: Exposure to grain dust and diesel exhaust accentuated respiratory disorders with declines in lung functions amongst grain millers. Improved milling practices and engaging cleaner milling facilities should be adopted to minimize exposure and related hazards.

A Bayesian Approach for Record Value Statistics Model Using Nonhomogeneous Poisson Process

  • Kiheon Choi;Hee chual Kim
    • Communications for Statistical Applications and Methods
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    • v.4 no.1
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    • pp.259-269
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    • 1997
  • Bayesian inference for a record value statistics(RVS) model of nonhomogeneous Poisson process is considered. We seal with Bayesian inference for double exponential, Gamma, Rayleigh, Gumble RVS models using Gibbs sampling and Metropolis algorithm and also explore Bayesian computation and model selection.

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Affecting factors to using oral health of korean adolescents (청소년의 치과진료기관 이용여부에 영향을 미치는 요인)

  • Jeon, Mee-Jin
    • Journal of Korean society of Dental Hygiene
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    • v.10 no.4
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    • pp.607-616
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    • 2010
  • Objectives : This study was performed to enhance a rate of Using oral clinic and to search related factors of using oral clinics. Methods : The subjects of the study were 74,698 subjects who answered to the 2007 korea Youth Risk Behavior Web-based survey. Answers of 73,836 subjects were used for the final analysis. We used spss of version 12.0. This study conducted a Chi-square test to identify using oral clinics rate according to characteristics of subjects and a multivariate logistic regression analysis to identify whether they are independently significant. Results : Tooth scaling experiences were responded by 10,060 subjects(25.6%). Grade and metropolis, economic level had significant associations with using oral clinic experiences. The rate of using oral clinic showed significant difference in point, depending on general characteristics. Their oral health showed significant difference in point between using oral clinic experience and non-experience groups. According to the multiple logistics regression analysis whose significant independent variables were sex, grade, metropolis, economic level, blooding gum, tooth brushing, oral malodor. Conclusions : The policy is needed to prevent economic constraints from worsening oral health by supporting the poor. And our government should eventually prepare a public relation program suitable for public.