사전검사를 통한 고립성 폐결절 환자에서의 악성 확률 타당성에 대한 연구

장주현 ( Joo Hyun Jang ),박성훈 ( Sung Hoon Park ),최정희 ( Jeong Hee Choi ),이창률 ( Chang Youl Lee ),황용일 ( Yong Il Hwang ),신태림 ( Tae Rim Shin ),박용범 ( Yong Bum Park ),이재영 ( Jae Young Lee ),장승훈 ( Seung Hun Jang ) 대한결핵 및 호흡기학회 2009 Tuberculosis and Respiratory Diseases Vol.67 No.2

Background: Solitary pulmonary nodules (SPN) are encountered incidentally in 0.2% of patients who undergo chest X-ray or chest CT. Although SPN has malignant potential, it cannot be treated surgically by biopsy in all patients. The first stage is to determine if patients with SPN require periodic observation and biopsy or resection. An important early step in the management of patients with SPN is to estimate the clinical pretest probability of a malignancy. In every patient with SPN, it is recommended that clinicians estimate the pretest probability of a malignancy either qualitatively using clinical judgment or quantitatively using a validated model. This study examined whether Bayesian analysis or multiple logistic regression analysis is more predictive of the probability of a malignancy in SPN. Methods: From January 2005 to December 2008, this study enrolled 63 participants with SPN at the Kangnam Sacred Hospital. The accuracy of Bayesian analysis and Bayesian analysis with a FDG-PET scan, and Multiple logistic regression analysis was compared retrospectively. The accurate probability of a malignancy in a patient was compared by taking the chest CT and pathology of SPN patients with <30 mm at CXR incidentally. Results: From those participated in study, 27 people (42.9%) were classified as having a malignancy, and 36 people were benign. The result of the malignant estimation by Bayesian analysis was 0.779 (95% confidence interval [CI], 0.657 to 0.874). Using Multiple logistic regression analysis, the result was 0.684 (95% CI, 0.555 to 0.796). This suggests that Bayesian analysis provides a more accurate examination than multiple logistic regression analysis. Conclusion: Bayesian analysis is better than multiple logistic regression analysis in predicting the probability of a malignancy in solitary pulmonary nodules but the difference was not statistically significant.

The Textbook Analysis on Probability: The Case of Korea, Malaysia and U.S. Textbooks

( Han Sunyoung ),( Rosli Roslinda ),( Capraro Robert M. ),( Capraro Mary M. ) 한국수학교육학회 2011 수학교육연구 Vol.15 No.2

"Statistical literacy" is important to be an effective citizen ([Gal, I. (2005). Towards "probability literacy" for all citizens: Building blocks and instructional dilemmas. In: G. A. Jones (Ed.), Exploring probability in school: Challenges for teaching and learning (pp. 39-63). New York: Springer]). Probability and statistics has been connected with real context and can be used to stimulate students` creative abilities. This study aims at identifying the extent that textbooks in three countries include experimental probability concepts and non-routine, open-ended, application and contextual problems. How well textbooks reflect real application situations is important in the sense that students can employ probability concepts when solving real world problems. Results showed that three textbook series did not mention experimental probability. Furthermore, all of textbooks had more routine, close-ended, knowing, and non-contextual problems.

A Study on the Quantitative Determination of Failure Effect Probability for Criticality Analysis on System

이명석,최성대,허장욱 한국기계가공학회 2019 한국기계가공학회지 Vol.18 No.8

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.

Validation of Statistical Analysis-based Aberrancy Probability Using Marine Simulations

김성철 해양환경안전학회 2018 海洋環境安全學會誌 Vol.24 No.3

To perform the Maritime Safety Audi Scheme, 10-4 was constantly applied without adjustment when evaluating the proximity of the fairway. The necessity of applying the different aberrancy probabilities from the different proximity of the fairway depending on the shape of the route and the size of the ship was validated using marine simulations. Marine simulation was performed to evaluate the validity of statistical analysis-based aberrancy probability according to the different shapes of routes and ship size presented in the previous study. As results, the validity of the criterion of the statistical analysis-based aberrancy probability was confirmed by comparing with the results of simulation-based aberrancy probabilities. The results support that the aberrancy probabilities by the types of a vessel could be different based on the type and size of vessels. The results motivate that further investigation is required to find the reasonable criteria of the aberrancy probabilities for the maritime traffic safety audit according to the fairway shape and the size of the vessel.

조건부확률 개념의 교수학적 분석과 이해 분석

이정연,우정호 대한수학교육학회 2009 수학교육학연구 Vol.19 No.2

The notions of conditional probability and independence are fundamental to all aspects of probabilistic reasoning. Several previous studies identified some misconceptions in students' thinking in conditional probability. However, they have not analyzed enough the nature of conditional probability. The purpose of this study was to analyze conditional probability and students' knowledge on conditional probability. First, we analyzed the conditional probability from mathematical, historico-genetic, psychological, epistemological points of view, and identified the essential aspects of the conditional probability. Second, we investigated the high school students' and undergraduate students' thinking in conditional probability and independence. The results showed that the students have some misconceptions and difficulties to solve some tasks with regard to conditional probability. Based on these analysis, the characteristics of reasoning about conditional probability are investigated and some suggestions are elicited. 이 연구는 조건부확률 개념에 대한 교수학적 분석을 시도하고, 학생들의 조건부확률 개념의 이해에 관하여 분석하였다. 수학적, 역사 발생적, 심리학적, 인식론적 관점의 분석을 통하여, 조건사건을 표본공간으로 하는 확률이라는 대상 개념, 사전확률이 사후확률로 변화하는 확률 수정의 과정 개념, 조건사건의 확인, 사건의 시간 순서와 조건관계의 구분, 인과관계와 조건관계의 구분, 가추적 사고의 이해가 조건부확률 이해의 핵심적인 요소임을 확인하였다. 또한, 고등학생과 대학생의 지필 검사와 면담을 통하여 학생들의 이해와 오개념에 대해 분석하였다. 이를 토대로 교육과정에의 시사점을 도출하였다.

Validation of Statistical Analysis-based Aberrancy Probability Using Marine Simulations

Sung-Cheol Kim 해양환경안전학회 2018 해양환경안전학회지 Vol.24 No.3

To perform the Maritime Safety Audi Scheme, 10-4 was constantly applied without adjustment when evaluating the proximity of the fairway. The necessity of applying the different aberrancy probabilities from the different proximity of the fairway depending on the shape of the route and the size of the ship was validated using marine simulations. Marine simulation was performed to evaluate the validity of statistical analysis-based aberrancy probability according to the different shapes of routes and ship size presented in the previous study. As results, the validity of the criterion of the statistical analysis-based aberrancy probability was confirmed by comparing with the results of simulation-based aberrancy probabilities. The results support that the aberrancy probabilities by the types of a vessel could be different based on the type and size of vessels. The results motivate that further investigation is required to find the reasonable criteria of the aberrancy probabilities for the maritime traffic safety audit according to the fairway shape and the size of the vessel.

Validation of Statistical Analysis-based Aberrancy Probability Using Marine Simulations

Kim, Sung-Cheol The Korean Society of Marine Environment and safet 2018 해양환경안전학회지 Vol.24 No.3

To perform the Maritime Safety Audi Scheme, $10^{-4}$ was constantly applied without adjustment when evaluating the proximity of the fairway. The necessity of applying the different aberrancy probabilities from the different proximity of the fairway depending on the shape of the route and the size of the ship was validated using marine simulations. Marine simulation was performed to evaluate the validity of statistical analysis-based aberrancy probability according to the different shapes of routes and ship size presented in the previous study. As results, the validity of the criterion of the statistical analysis-based aberrancy probability was confirmed by comparing with the results of simulation-based aberrancy probabilities. The results support that the aberrancy probabilities by the types of a vessel could be different based on the type and size of vessels. The results motivate that further investigation is required to find the reasonable criteria of the aberrancy probabilities for the maritime traffic safety audit according to the fairway shape and the size of the vessel.

물류보관 랙선반시설물의 시스템신뢰성 해석

옥승용 ( Seung Yong Ok ),김동석 ( Dong Seok Kim ) 한국안전학회(구 한국산업안전학회) 2014 한국안전학회지 Vol.29 No.4

This study proposes a system reliability analysis of rack storage facilities subjected to forklift colliding events. The proposedsystem reliability analysis consists of two steps: the first step is to identify dominant failure modes that most contribute to the failure ofthe whole rack facilities, and the second step is to evaluate the system failure probability. In the first step, dominant failure modes areidentified by using a simulation-based selective searching technique where the contribution of a failure mode to the system failure isroughly estimated based on the distance from the origin in the space of the random variables. In the second step, the multi-scale systemreliability method is used to compute the system reliability where the first-order reliability method (FORM) is initially used to evaluatethe component failure probability (failure probability of one member), and then the probabilities of the identified failure modes and theirstatistical dependence are evaluated, which is called as the lower-scale reliability analysis. Since the system failure probability iscomprised of the probabilities of the failure modes, a higher-scale reliability analysis is performed again based on the results of thelower-scale analyses, and the system failure probability is finally evaluated. The illustrative example demonstrates the results of thesystem reliability analysis of the rack storage facilities subjected to forklift impact loadings. The numerical efficiency and accuracy of theapproach are compared with the Monte Carlo simulations. The results show that the proposed two-step approach is able to provideaccurate reliability assessment as well as significant saving of computational time. The results of the identified failure modes additionallylet us know the most-critical members and their failure sequence under the complicated configuration of the member connections.

지역난방 열배관망 운영데이터 기반의 파손확률 모델 개발

김형석 ( Hyoung Seok Kim ),김계범 ( Gye Beom Kim ),김래현 ( Lae Hyun Kim ) 한국화학공학회 2017 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.55 No.3

지역난방은 국내에 1985년 처음 도입되었다. 지하 열배관망의 사용연한이 30년 이상 증가함에 따라, 지하에 매설된 열수송 배관 특성상 유지관리가 중요한 문제로 대두되고 있다. 노후화가 진행된 열배관망 유지보수를 위한 정기적인 점검, 운영관리 시 다양한 복합 기술이 필요하다. 특히 현장에서 경제적 관점에서 최적 유지보수 및 교체시점을 도출하기 위하여 의사결정에 활용될 수 있는 모형개발이 요구되고 있다. 본 연구에서는 한국지역난방공사 수도권 5개 지사열 배관망 운영 시 보수이력과 사고성 데이터를 바탕으로 분석하였다. 정성적 분석과 이항 로지스틱 회귀분석의 통계적 기법을 도입하여 파손확률 모델을 개발하였다. 보수이력 및 사고성 자료의 정성적 분석 결과, 파이프라인 손상의 가장 중요한 원인으로 건설 시공불량, 배관의 부식과 자재 불량이 전체의 약 82%를 차지했다. 통계 모델 분석에서는 분류의 분리 점을 0.25로 설정함으로써 열배관 파손 및 비 파손 분류의 정확도가 73.5%로 향상 되었다. 파손확률 모델 수립을 위해 Hosmer와 Lemeshow 검정과 독립변수의 유의성 검정, 모델의 Chi-Square 검정을 통해 모델의 적합성을 검증 하였다. 열배관망 파손의 위험순위 분석결과에 따르면 파손확률을 가장 높이는 경우는 겨울철 서울지역 자동차 도로에 있는 10년 이상 된 250mm이하 배관 Reducer에서 F 건설회사가 시공했던 열배관망으로 분석되었다. 본 연구 결과는 열배관망 시스템의 유지관리 및 예방점검, 교체 사업 우선순위를 정할 때 활용 가능하다. 또한 이를 통하여 점검·유지보수 등 사전에 사고예방 계획을 수립하여 대처함으로써 열배관 파손의 빈도를 감소시키고 보다 적극적인 열배관망 관리에 이용할 수 있을 것으로 사료된다. District heating was first introduced in Korea in 1985. As the service life of the underground thermal piping network has increased for more than 30 years, the maintenance of the underground thermal pipe has become an important issue. A variety of complex technologies are required for periodic inspection and operation management for the maintenance of the aged thermal piping network. Especially, it is required to develop a model that can be used for decision making in order to derive optimal maintenance and replacement point from the economic viewpoint in the field. In this study, the analysis was carried out based on the repair history and accident data at the operation of the thermal pipe network of five districts in the Korea District Heating Corporation. A failure probability model was developed by introducing statistical techniques of qualitative analysis and binomial logistic regression analysis. As a result of qualitative analysis of maintenance history and accident data, the most important cause of pipeline damage was construction erosion, corrosion of pipe and bad material accounted for about 82%. In the statistical model analysis, by setting the separation point of the classification to 0.25, the accuracy of the thermal pipe breakage and non-breakage classification improved to 73.5%. In order to establish the failure probability model, the fitness of the model was verified through the Hosmer and Lemeshow test, the independent test of the independent variables, and the Chi-Square test of the model. According to the results of analysis of the risk of thermal pipe network damage, the highest probability of failure was analyzed as the thermal pipeline constructed by the F construction company in the reducer pipe of less than 250mm, which is more than 10 years on the Seoul area motorway in winter. The results of this study can be used to prioritize maintenance, preventive inspection, and replacement of thermal piping systems. In addition, it will be possible to reduce the frequency of thermal pipeline damage and to use it more aggressively to manage thermal piping network by establishing and coping with accident prevention plan in advance such as inspection and maintenance.

한국 상장 중소기업의 소유구조와 생존확률

김동욱,김병곤 한국산업경제학회 2019 산업경제연구 Vol.32 No.6

The purpose of this study is conducting the survival analysis for Korean listed small and medium enterprises(SMEs). Using cross-sectional and time series data on total 12,704 Korean listed SMEs, we estimate the survival probability with the life table and Kaplan-Meier survival curve. Also we analysis the effect of ownership structure on corporate survival. The results are as follows. First, cumulative 5-year survival probability is 99.98% and cumulative 65-year survival probability is 56.97%. The survival probability until the 10th year is considerably high, and then the probability is sharply deceased. Second, when the samples are divided by three sectors of manufacturing, distribution and service, and construction, the survival probabilities are no difference until the 10th year among the sectors. But after 10th year, distribution and service sector’s survival probability is more sharply decreased, than that of manufacturing and construction sectors. Third, Korean listed SMEs ownership structure effects on corporate survival probability. As the insider ownership and the ratio of outside directors increase, the survival probability also increase. 본 연구에서는 생존분석을 응용하여 한국 상장 중소기업의 생존확률을 추정하고, 소유구조와 기업생존 간의 관계를 분석하였다. 분석기간은 1998년부터 2017년까지이다. 표본은 한국거래소 유가증권시장과 코스닥시장에 상장된 총 12,704개(연도-기업) 중소기업을 대상으로 하였다. 실증분석 결과를 요약하면 다음과 같다. 첫째, 한국 상장 중소기업의 경우 생존기간 10년까지는 비교적 높은 생존확률을 보여 기업실패 가능성이 낮은 것으로 나타났다. 그러나 10년 이후에는 생존확률이 크게 하락하면서 전형적인 계단함수 형태를 보였다. 전체 표본기업을 제조업, 유통·서비스업, 건설업 등으로 분류하여 각 업종의 생존곡선을 비교했을 때 약 10년 생존기간까지는 3개 업종의 생존확률에 큰 차이가 없는 것으로 나타났다. 그렇지만 이후 기간에서는 제조업과 건설업에 비해 유통·서비스업종의 생존확률이 급속히 하락하는 것을 발견하였다. 둘째, 한국 상장 중소기업에 있어 소유구조는 기업의 생존에 주요한 영향 요인이라는 것을 확인하였다. 내부지분율이 높은 기업은 생존 가능성이 높다는 것을 알 수 있었다. 내부지분율이 높으면 내부경영자와 외부주주 간의 정보불균형이 축소되고, 이해가 일치되어 대리인문제가 완화됨으로써 기업생존 가능성이 높아지는 것으로 이해할 수 있었다. 또한 이사회에 사외이사비율이 높을수록 기업의 생존 가능성이 높아진다는 것을 알 수 있었다. 이사회에 사외이사가 많이 포함될수록 이사회의 전문성이 높아지고, 사외이사가 경영자를 통제·감시함으로써 기업의 생존 가능성이 높아지는 것으로 이해할 수 있었다.