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공정시스템 이동현상 화학공정안전 : 재순환 제품을 가진 다목적 회분식공정의 조업완료시간 결정 알고리즘 및 최적생산계획
박상대(Sang Dae Park),김양진(Yang Jin Kim),정재학(Jae Hak Jung) 한국화학공학회 2000 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.38 No.6
Even though the efficiency of batch process is lower than that of continuous process, the batch process has been increased in the chemical process industry over past decade. The batch process is more suitable process to meet with the frequent changes of demands as the taste of consumers is changed within short period and life cycle of products is shortened. The researches have been classified the chemical batch process into two types, multi-product batch process and multipurpose batch process. Until now, the multi-purpose batch process had received little attention than multi-product batch process by researchers because of several characteristics which is hard to deal with such as irregularity of production path, existence of infeasible operation sequence and complexity of operation. Park and Jung[13-14] have studied the completion times algorithm and the optimal scheduling for multi-purpose batch process which have no recirculation products through the processing units. But in the case of real industry, for example the electronic semi-conductor industry, they usually have the products with recirculation path through the processing flow. So it can`t be argued without appropriate considering of recirculation of products flow. In this paper we have developed the completion times algorithms of single line multi-purpose batch process including recirculation products under consideration of the non-zero set-up times and transfer times. We also developed the optimization method, genetic algorithm, for optimal scheduling of multi-purpose batch process including recirculation products. Finally the performance of the proposed algorithms was tested by several randomly generated examples and the Gantt chart results are presented. We used Genetic Algorithm for solving the scheduling problems and optimal solutions are also presented.
박재학(Jai Hak Park),Gennadiy P. Nikishkov 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
A SGBEM-FEM alternating method is extended to analyze a through-thickness crack problem. The effect of shape of boundary element mesh on the accuracy of stress intensity factor is examined. It is noted that the fictitious portion of the boundary element mesh, which is located outside the body, plays an important role in the method. Also the effect of the boundary condition imposed on the edge of boundary element mesh is examined. In order to check the accuracy of the method, we considered a sample problem of a through-thickness crack with unequal surface lengths. The obtained stress intensity factors are compared with the known solutions or the results obtained from finite element method. Using the proposed method stress corrosion crack growth simulation is performed for a through-thickness crack with unequal surface lengths.
박재학(Jai Hak Park),최영환(Young Hwan Choi) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.10
원자력발전소의 배관에 대하여 행하는 검사는 배관의 구조건전성에 큰 영향을 미친다. 그러나 검사에는 많은 인력과 비용이 소요되므로 검사의 영향을 평가하여 최적의 검사주기와 검사품질을 결정하는 것이 중요하다. 본 논문에서는 원자력발전소 배관의 파손확률을 평가할 수 있도록 개발된 P-PIE 프로그램을 사용하여 검사의 유무, 검사주기 및 검사품질 등이 배관의 파손확률에 미치는 영향을 살펴보았다. 국내 원전의 배관 데이터를 사용하여 해석하였으며, 피로 및 부식에 의한 균열성장을 고려하였다. Pipe inspections conducted in nuclear power plants play an important role in ensuring the structural integrity of pipes. Because considerable manpower and expense is required for pipe inspections, it is very important to determine the optimum inspection period and the level of inspection. In this study, the effects of the period and the inspection quality on the failure probability of pipes are investigated using the P-PIE program, which has been developed to calculate the failure probability of pipes. The pipe data of an internal nuclear power plant is used in the study, and fatigue and stress corrosion crack growth are considered in the analysis.
박재학 ( Jai Hak Park ),이재봉 ( Jae Bong Lee ),최영환 ( Young Hwan Choi ) 한국안전학회(구 한국산업안전학회) 2011 한국안전학회지 Vol.26 No.2
The failure probabilities of pipes in nuclear power plants due to stress corrosion are obtained using the P-PIE program, which is developed for evaluating failure probability of pipes based on the existing PRAISE program. Leak, big leak and LOCA(loss of coolant accident) probabilities are calculated as a function of operating time for several pipes in a domestic nuclear plant. The sensitivity analysis is also performed to find out the important parameters for the failure of pipes due to stress corrosion. The results show that the steady state oxygen concentration and steady state temperature are important parameters and failure probability is very low when the oxygen concentration is maintained according to the regulation.
선형적으로 변하는 단면적을 가진 균열에서의 누설률 평가
박재학(Jai Hak Park) 대한기계학회 2016 大韓機械學會論文集A Vol.40 No.9
원자력 배관 설계에는 파단전 누설(leak before break, LBB) 개념이 사용되고 있다. LBB 개념의 적용을 위해서는 관통균열을 통한 누설률을 정확하게 예측할 수 있어야 한다. 단면적이 일정한 관통균열에 대한 누설률 해석은 많이 이루어지고 있으나 실제 관찰되는 관통균열에서는 배관 내면 쪽과 외면 쪽의 단면적이 다른 경우가 많이 발생된다. 따라서 본 논문에서는 유동경로를 따라 선형적으로 변화하는 단면적을 가진 관통균열에 대하여 누설률을 평가하여 단면적의 분포가 누설률에 미치는 영향을 살펴보았다. 또한 클래딩 등에 의하여 두께 방향으로 이중 재료로 된 배관에 존재하는 관통균열에 대해서도 누설률을 평가하여 유동경로를 따라 달라지는 균열면 형태학적 변수가 누설률에 미치는 영향을 살펴보았다. The leak before break (LBB) concept is used in pipe line design for nuclear power plants. For application of the LBB concept, leak rates through cracks should be evaluated accurately. Usually leak late analyses are performed for through-thickness cracks with constant cross-sectional area. However, the cross-sectional area at the inner pipe surface of a crack can be different from that at the outer surface. In this paper, leak rate analyses are performed for the cracks with linearly-varying cross-sectional areas. The effect of varying the cross-sectional area on leak rates was examined. Leak rates were also evaluated for cracks in bi-material pipes. Finally, the effects of crack surface morphology parameters on leak rates were examined.
The Relationship between Maternal Parenting Factors and Infants’ Temperament
박재학(Park Jae hak),조재숙(Jo Jae Sook),이덕현(Lee Dok hyun) 숭실대학교 영재교육연구소 2018 Global Creative Leader Vol.8 No.3
본 연구는 영아 기질의 하위요인 사회성, 활동성, 정서성과 주 양육자가 되는 어머니의 주요 양육요인인 자아존중감, 사회적 양육, 자녀가치, 자기효능감, 양육스트레스, 우울 간의 관계에 분석하였다. 이를 위하여 2010년도에 조사한 한국아동패녈 3차년도 자료를 활용하여 두 독립표본 t-test, 상관관계분석, 중다회귀분석을 이용하여 분석하였다. 분석결과는 다음과 같다. 첫째, 어머니의 양육요인들은 영아의 기질과 서로 관련성이 높았다. 둘째, 어머니의 양육요인 중 긍정적 요인이 되는 자아존중감, 사회적 양육, 자녀에 대한 정서적 가치기대는 영아의 기질에 긍정적인 영향을 끼치는 것으로 나타났다. 이에 따라 영아의 사회성, 활동성, 정서성 등 기질을 높이기 위하여 어머니의 양육요인 중 긍정적인 양육요인에 더 많은 관심을 가질 것을 제안하였다. 본 연구는 영아에 대한 연구에 있어 기질을 변하지 않는 요인으로 고정하지 않고 변할 수 있는 요인으로 상정하여 연구하였다는데 의의가 있다. The purpose of this study was to investigate the relationship between sociability, activity and emotionality of infants, which are the sub-factors of temperament, and their mothers self-esteem, social parenting, value of children, self-efficacy, parenting stress and depression, which are the major factors of maternal parenting. The 3rd-year data of Panel Study on Korean Children were used, and two independent samples t-test, correlation analysis and multiple regression analysis were carried out to analyze the data. The findings of the study were as follows: First, there were close mutual relationships between the maternal parenting factors and infant temperament. Second, the self-esteem, social upbringing, and emotional value expectations of children, which are positive factors of mothers’parenting, have a positive effect on infant temperament. Given the findings of the study, temperament should be regarded as a variable factor, rather than as an invariable one, in studies of infants and preschoolers. This study implies that the research on infant studies is based on factors that can be changed without changing the temperament.