• Nuclear Engineering and Technology
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• 제49권6호
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• pp.1301-1309
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• 2017

The extinction probability of a branching process (a neutron chain in a multiplying medium) is calculated for a system randomly varying in time. The evolution of the first two moments of such a process was calculated previously by the authors in a system randomly shifting between two states of different multiplication properties. The same model is used here for the investigation of the extinction probability. It is seen that the determination of the extinction probability is significantly more complicated than that of the moments, and it can only be achieved by pure numerical methods. The numerical results indicate that for systems fluctuating between two subcritical or two supercritical states, the extinction probability behaves as expected, but for systems fluctuating between a supercritical and a subcritical state, there is a crucial and unexpected deviation from the predicted behaviour. The results bear some significance not only for neutron chains in a multiplying medium, but also for the evolution of biological populations in a time-varying environment.

• Journal of Korea Trade
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• 제25권5호
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• pp.110-128
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• 2021

Purpose - The essential purpose of this study is to analyze the possibility of substitution of an individual job resulting from technological development represented by the 4th Industrial Resolution, considering the different effects of digital transformation on the labor market. Design/methodology - In order to estimate the substitution probability, this study used two data sets which the job characteristics data for individual occupations provided by KEIS and the information on occupational status of substitution provided by Frey and Osborne(2013). In total, 665 occupations were considered in this study. Of these, 80 occupations had data with labels of substitution status. The primary goal of estimation was to predict the degree of substitution for 607 of 665 occupations (excluding 58 with markers). It utilized three methods a principal component analysis, an unsupervised learning methodology of machine learning, and Ridge and Lasso from supervised learning methodology. After extracting significant variables based on the three methods, this study carried out logistics regression to estimate the probability of substitution for each occupation. Findings - The probability of substitution for other occupational groups did not significantly vary across individual models, and the rank order of the probabilities across occupational groups were similar across models. The mean of three methods of substitution probability was analyzed to be 45.3%. The highest value was obtained using the PCA method, and the lowest value was derived from the LASSO method. The average substitution probability of the trading industry was 45.1%, very similar to the overall average. Originality/value - This study has a significance in that it estimates the job substitution probability using various machine learning methods. The results of substitution probability estimation were compared by industry sector. In addition, This study attempts to compare between trade business and industry sector.

• 대한간호학회지
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• 제45권5호
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• pp.641-649
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• 2015

Purpose: The purpose of this study was to introduce the main concepts of statistical testing and effect size and to provide researchers in nursing science with guidance on how to calculate the effect size for the statistical analysis methods mainly used in nursing. Methods: For t-test, analysis of variance, correlation analysis, regression analysis which are used frequently in nursing research, the generally accepted definitions of the effect size were explained. Results: Some formulae for calculating the effect size are described with several examples in nursing research. Furthermore, the authors present the required minimum sample size for each example utilizing G*Power 3 software that is the most widely used program for calculating sample size. Conclusion: It is noted that statistical significance testing and effect size measurement serve different purposes, and the reliance on only one side may be misleading. Some practical guidelines are recommended for combining statistical significance testing and effect size measure in order to make more balanced decisions in quantitative analyses.

• 한국조리학회지
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• 제14권4호
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• pp.119-133
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• 2008

This study researched the effect of initial expenses for food service business and shop characteristics on the motive of starting business through questionnaires(from April to May, 2008). The results are as follows. First, for the hypothesis, 'the motive of starting business depends on its initial expenses', the significance probability of good commercial area was .015 and that of retirement was .020, showing statistically significant difference. F values were 2,889 and 2.734 each, which showed significant difference by 0.001. Second, for the hypothesis, 'the motive of starting business depends on shop characteristics', the significance probability of the accomplishment desire, the future stability and the retirement were .011, .009, and .025 each, showing statistically significant difference. F values were 2,616, 3.034 and 3.177 each, showing significant difference by .001. Lastly, initial expenses for business and shop characteristics showed significant difference according to the demographical variables on the motive of starting business. This study shows the problem of starting business with no extra funds. It is important to reflect the opinions of founders about the commercial building lease protection law for them to concentrate on business. The founders should research for menu and systems and be aware of the tendency of the industry for sure.

• Smart Structures and Systems
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• 제33권2호
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• pp.105-118
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• 2024

In order to realize tiny bridge crack discovery by UAV-based machine vision, a novel method combining deep learning and tensor voting is proposed. Firstly, the grid images of crack are detected and descripted based on SE-ResNet50 to generate feature points. Then, the probability significance map of crack image is calculated by tensor voting with feature points, which can define the direction and region of crack. Further, the crack detection anchor box is formed by non-maximum suppression from the probability significance map, which can improve the robustness of tiny crack detection. Finally, a case study is carried out to demonstrate the effectiveness of the proposed method in the Xiangjiang-River bridge inspection. Compared with the original tensor voting algorithm, the proposed method has higher accuracy in the situation of only 1-2 pixels width crack and the existence of edge blur, crack discontinuity, which is suitable for UAV-based bridge crack discovery.

• Smart Structures and Systems
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• 제25권5호
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• pp.593-604
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• 2020

Temperature may have more significant influences on structural responses than operational loads or structural damage. Therefore, a comprehensive understanding of temperature distributions has great significance for proper design and maintenance of bridges. In this study, the temperature distribution of the steel box girder is systematically investigated based on the structural health monitoring system (SHMS) of the Sutong Cable-stayed Bridge. Specifically, the characteristics of the temperature and temperature difference between different measurement points are studied based on field temperature measurements. Accordingly, the probability density distributions of the temperature and temperature difference are calculated statistically, which are further described by the general formulas. The results indicate that: (1) the temperature and temperature difference exhibit distinct seasonal characteristics and strong periodicity, and the temperature and temperature difference among different measurement points are strongly correlated, respectively; (2) the probability density of the temperature difference distribution presents strong non-Gaussian characteristics; (3) the probability density function of temperature can be described by the weighted sum of four Normal distributions. Meanwhile, the temperature difference can be described by the weighted sum of Weibull distribution and Normal distribution.

• Earthquakes and Structures
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• 제15권2호
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• pp.193-202
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• 2018

This paper studied the probability of pounding occurred between decks and abutments of a long span high-pier continuous rigid fame bridge subjected to ground motions with local soil effect. A pounding probability analysis methodology has been proposed using peak acceleration at bedrock as intensity measure (IM) for multi-support seismic analysis. The bridge nonlinear finite element (FE) models was built with four different separation distances. Effect of actual site condition and non-uniform spatial soil profiles on seismic wave propagating from bedrock to ground surface is modelled. Pounding probability of the high-pier bridge under multi-support seismic excitations (MSSE) is analyzed based on the nonlinear incremental dynamic analysis (n-IDA). Pounding probability results under uniform excitations (UE) without actual local site effect are compared with that under MSSE with site effect. The study indicates that the required design separation length between deck and abutment under uniform excitations is larger than that under MSSE as the peak acceleration at bedrock increases. As the increase of both separation distance between deck and abutment and the peak acceleration, the probability of pounding occurred at a single abutment or at two abutments simultaneously under MSSE is less than that under UE. It is of great significance considering actual local site effect for determining the separation distance between deck and abutment through the probability pounding analysis of the high-pier bridge under MSSE.

• 미생물학회지
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• 제47권3호
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• pp.263-267
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• 2011

유전체 지문 분석법은 세균 균주간의 친연성을 판정하는데 유용하다. 그러나 친연성이 낮은 두 균주의 지문 사이에서 우연히 발생하는 DNA 단편 크기의 일치성은 유전형질의 일치성의 해석에 오차를 유발한다. 본 연구는 임의의 두 유전체 지문에서 우연히 DNA 단편의 크기가 일치할 확률을 정량하여, 유전체 지문에 근거한 친연성 해석의 유의성을 고찰하였다. 유전형질 일치성 없이 단편 크기가 일치할 확률은 관찰되는 단편의 수, 관찰 가능한 전체 단편의 수와 크기가 일치하는 단편의 수로부터 계산될 수 있는 함수로 분석되었다. 유의성에 가장 큰 영향을 미치는 독립 매개변수는 전체 단편의 수였으며, 우연한 공통 단편의 수를 10개 미만으로 유지하기 위해서는 약 200개 이상의 단편이 지문에서 관찰될 수 있어야 하는 것으로 계산되었다.

• 한국방사선학회논문지
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• 제15권7호
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• pp.1015-1020
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• 2021

본 연구는 2020년 1월부터 2021년 6월까지 부산지역 일개 의료기관을 방문하여 골다공증 검사를 시행한 환자 중 특별한 질환이 없는 건강한 폐경 후 여성 113명의 검사 결과지를 후향적으로 분석하였다. 연구 목적은 폐경 여성의 BMI(신체질량지수)가 골밀도에 미치는 영향을 알아보고자 하였으며 저체중(BMI<18.5) 환자의 요추부와 대퇴부의 분석결과 유의확률(p-value) 0.000으로 나타났으며 정상체중(18.5≦BMI<23.0) 환자의 요추부에서 유의확률(p-value)은 0.025, 대퇴부의 유의확률(p-value)은 0.012로 나타났다. 과체중(23.0≦BMI<25.0) 환자의 요추부의 유의확률(p-value)은 0.021, 대퇴부의 유의확률(p-value)은 0.034로 나타나 상관 관계가 확인되었다. 그러나 고도비만(30.0≦BMI<40.0) 환자의 요추부 유의확률(p-value)은 0.127, 대퇴부의 유의확률(p-value)은 0.093으로 요추부와 대퇴부 모두에서 유의확률 p>0.05로 나타나 BMI와 골밀도의 상관 관계가 없음을 알 수 있다.

• 보건행정학회지
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• 제11권1호
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• pp.1-18
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• 2001

The purpose of the present study was to assess the agreement of survival probability estimated by International Classification of Diseases l0th Edition(ICD-10) based International Classification of Diseases based Injury Severity Score(ICISS) with professional panel's judgment on preventable death. ICISS has a promise as an alternative to Trauma and Injury Severity Score(TRISS) which have served as a standard measure of trauma severity, but requires more validation studies. Furthermore as original version of ICISS was based ICD-9CM, it is necessary to test its performance employing ICD-10 which has been used in Korea and is expected to replace ICD-9 in many countries sooner or later. Methods : For 1997 and 1998 131 trauma deaths and 1,785 blunt trauma inpatients from 6 emergency medical centers were randomly sampled and reviewed. Trauma deaths were reviewed by professional panels with hospital records and survival probability of trauma inpatients was assessed using ICD-10 based ICISS. For trauma mortality degree of agreement between ICISS survival probability with judgment of professional panel on preventable death was assessed and correlation between W-score and preventable death rate by each emergency medical center was assessed. Results : Overall agreement rate of ICISS survival probability with preventable death judged by professional panel was 66.4%(kappa statistic 0.36). Spearman's correlation coefficient between W-score and preventable death rate by each emergency medical center was -0.77(p=0.07) and Pearson's correlation coefficient between them was -0.90(p=0.01). Conclusions : The agreement rate of ICD-10 based ICISS survival probability with of professional panel's judgment on preventable death was similar to TRISS. The W-scores of emergency medical centers derived from ICD-10 based ICISS were highly correlated with preventable death rates of them with marginal statistical significance.