• Title/Summary/Keyword: Safety problem

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Measure of Evaluation for Non-Normal Process Capability (비정규 공정능력 평가의 측도)

  • 김홍준;김진수;전창희
    • Journal of the Korea Safety Management & Science
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    • v.2 no.2
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    • pp.41-55
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    • 2000
  • The main objective of this paper is to propose a measure of evaluation for non-normal process capability. If a process is not normally distributed, but normal-based techniques are used, serious errors can result. Our approach to solve this problem is that the Pearson system, the Johnson system, and the Burr system are selected for estimating a measure of process capability using the percentage nonconforming. In this paper, we found that the Pearson system and the Johnson system were a conparatively reasonable methods to calculate out of specification by example.

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Franchise Application by Knowledge Management Success Enterprise Cases (지식경영 성공기업 사례를 통한 프랜차이즈 적용)

  • Lee, Seong-Ho;Park, No-Guk;Kim, Seong-Yun
    • Proceedings of the Safety Management and Science Conference
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    • 2008.11a
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    • pp.383-393
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    • 2008
  • In this thesis, We analyzed success enterprise case which is well worked by knowledge and is gained effect results. We searched key factor for success knowledge management and found problem which is able to happen when is introduced by success enterprise in knowledge management. We applied to in franchise real field with key factor found above results and experimented others real fields.

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An Investigation of Health and Safety Measures in a Hydroelectric Power Plant

  • Acakpovi, Amevi;Dzamikumah, Lucky
    • Safety and Health at Work
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    • v.7 no.4
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    • pp.331-339
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    • 2016
  • Background: Occupational risk management is known as a catalyst in generating superior returns for all stakeholders on a sustainable basis. A number of companies in Ghana implemented health and safety measures adopted from international companies to ensure the safety of their employees. However, there exist great threats to employees' safety in these companies. The purpose of this paper is to investigate the level of compliance of Occupational Health and Safety management systems and standards set by international and local legislation in power producing companies in Ghana. Methods: The methodology is conducted by administering questionnaires and in-depth interviews as measuring instruments. A random sampling technique was applied to 60 respondents; only 50 respondents returned their responses. The questionnaire was developed from a literature review and contained questions and items relevant to the initial research problem. A factor analysis was also carried out to investigate the influence of some variables on safety in general. Results: Results showed that the significant factors that influence the safety of employees at the hydroelectric power plant stations are: lack of training and supervision, non-observance of safe work procedures, lack of management commitment, and lack of periodical check on machine operations. The study pointed out the safety loopholes and therefore helped improve the health and safety measures of employees in the selected company by providing effective recommendations. Conclusion: The implementation of the proposed recommendations in this paper, would lead to the prevention of work-related injuries and illnesses of employees as well as property damage and incidents in hydroelectric power plants. The recommendations may equally be considered as benchmark for the Safety and Health Management System with international standards.

Optimal Design for Reliability with Lognormally Distributed Stress and Strength (대수(對數) 정규분포(正規分布)를 하는 부하(負荷)와 강도(强度) 신뢰성(信賴性)모델에서의 최적화(最適化) 설계(設計)에 관(關)한 연구(硏究)(I))

  • Kim, Bok-Man;Hwang, Ui-Cheol
    • Journal of Korean Society for Quality Management
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    • v.18 no.2
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    • pp.43-53
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    • 1990
  • Mechanical components and structures are a major part of complex systems and the conseguences of their failure can be extremely costly. The ultimate goal of design engineers is to optimize these mechanical and structural design from the point of view of cost, reliability, weight, volume, maintainability and safety. An essential requirement of design optimization is to develop mathematical models for reliability at design stage. This paper is to minimize the cost of resources subject to the constraint that the reliability of the system must meet a specified level. The lagrange multiplier method is used to optimize the lognormal stress-lognormal strength problem. This optimization problem can be reduced to a search problem in one variable. A numerical example is presented to illustrate the optimization problem.

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A Bottleneck-Based Production Scheduling under Fuzzy Environment (퍼지 환경하에서 품질수준 확보를 위한 일정계획에 관한 연구 -Bottleneck을 고려한 생산라인에서-)

  • Lee, Sang Wan;Shin, Dae Hyuk
    • Journal of Korean Society for Quality Management
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    • v.23 no.3
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    • pp.156-166
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    • 1995
  • Job shop scheduling problem is a complex system and an NP-hard problem. Thus it is natural to look for heuristic method. We consider the multi-part production scheduling problem for quality level in a job shop scheduling under the existence of alternative routings. The problem is more complex if the processing time is imprecision. It requires suitable method to deal with imprecision. Fuzzy set theory can be useful in modeling and solving scheduling problems with uncertain processing times. Li-Lee fuzzy number comparison method will be used to compare processing times that evaluated under fuzziness. This study presents heuristic method for quality level in bottleneck-based job shop scheduling under fuzzy environment. On the basis of the proposed method, an example is presented.

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Study of Multi Floor Plant Layout Optimization Based on Particle Swarm Optimization (PSO 최적화 기법을 이용한 다층 구조의 플랜트 배치에 관한 연구)

  • Park, Pyung Jae;Lee, Chang Jun
    • Korean Chemical Engineering Research
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    • v.52 no.4
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    • pp.475-480
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    • 2014
  • In the fields of researches associated with plant layout optimization, the main goal is to minimize the costs of pipelines for connecting equipment. However, what is the lacking of considerations in previous researches is to handle the multi floor processes considering the safety distances for domino impacts on a complex plant. The mathematical programming formulation can be transformed into MILP (Mixed Integer Linear Programming) problems as considering safety distances, maintenance spaces, and economic benefits for solving the multi-floor plant layout problem. The objective function of this problem is to minimize piping costs connecting facilities in the process. However, it is really hard to solve this problem due to complex unequality or equality constraints such as sufficient spaces for the maintenance and passages, meaning that there are many conditional statements in the objective function. Thus, it is impossible to solve this problem with conventional optimization solvers using the derivatives of objective function. In this study, the PSO (Particle Swarm Optimization) technique, which is one of the representative sampling approaches, is employed to find the optimal solution considering various constraints. The EO (Ethylene Oxide) plant is illustrated to verify the efficacy of the proposed method.

Reliability Analysis of Ship Deck Structure (선체상갑판의 신뢰성해석)

  • S.J.,Yim;Y.S.,Yang;K.T.,Chung;C.W.,Kim;Y.S.,Suh
    • Bulletin of the Society of Naval Architects of Korea
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    • v.26 no.3
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    • pp.9-20
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    • 1989
  • It is important to enhance the safety of ship structures as much as possible in order to prevent the disastrous collapse of structures. In fact, the strength problem of structures is closely related with the safety problem of structures. Recently, the direct calculation method using a rational approach based on the first principle is implemented into the structural design process instead of adopting empirical approach based on the rules. The structural designer have shown increased concern with the problem of adequacy of conventional design method based on the safety factor since it does not fully take into account some degree of variability of the applied loads on and the strength of ship structures. To deal with the analysis of structures effectively, it is necessary to have three stages being equally treated. The first one is load analysis, second one response analysis, third one safety analysis. For marine structures, most of research effort has been however put into the first and second stages. The third stage is normally done by simple procedures. Hence, the various probabilistic methods are compared in order to establish the reliability analysis techniques for ship structures. As a result, the advanced level 2 method is selected as a most effective and accurate reliability method. The validity of this method is further demonstrated by comparing the results with the conventional method for the problem of the longitudinal strength of hull girder of Ro-Ro ship.

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The Research of Layout Optimization for LNG Liquefaction Plant to Save the Capital Expenditures (LNG 액화 플랜트 배치 최적화를 통한 투자비 절감에 관한 연구)

  • Yang, Jin Seok;Lee, Chang Jun
    • Korean Chemical Engineering Research
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    • v.57 no.1
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    • pp.51-57
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    • 2019
  • A plant layout problem has a large impact on the overall construction cost of a plant. When determining a plant layout, various constraints associating with safety, environment, sufficient maintenance area, passages for workers, etc have to be considered together. In general plant layout problems, the main goal is to minimize the length of piping connecting equipments as satisfying various constraints. Since the process may suffer from the heat and friction loss, the piping length between equipments should be shorter. This problem can be represented by the mathematical formulation and the optimal solutions can be investigated by an optimization solver. General researches have overlooked many constraints such as maintenance spaces and safety distances between equipments. And, previous researches have tested benchmark processes. What the lack of general researches is that there is no realistic comparison. In this study, the plant layout of a real industrial C3MR (Propane precooling Mixed Refrigerant) process is studied. A MILP (Mixed Integer Linear Programming) including various constraints is developed. To avoid the violation of constraints, penalty functions are introduced. However, conventional optimization solvers handling the derivatives of an objective functions can not solve this problem due to the complexities of equations. Therefore, the PSO (Particle Swarm Optimization), which investigate an optimal solutions without differential equations, is selected to solve this problem. The results show that a proposed method contributes to saving the capital expenditures.

Safety Assessment of LNG Transferring System subjected to gas leakage using FMEA and FTA

  • Lee, Jang-Hyun;Hwang, Seyun;Kim, Sungchan
    • Journal of Advanced Research in Ocean Engineering
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    • v.3 no.3
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    • pp.125-135
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    • 2017
  • The paper considers the practical application of the FMEA(Failure Mode and Effect Analysis) method to assess the operational reliability of the LNG(Liquefied Natural Gas) transfer system, which is a potential problem for the connection between the LNG FPSO and LNG carrier. Hazard Identification (HAZID) and Hazard operability (HAZOP) are applied to identify the risks and hazards during the operation of LNG transfer system. The approach is performed for the FMEA to assess the reliability based on the detection of defects typical to LNG transfer system. FTA and FMEA associated with a probabilistic risk database to the operation scenarios are applied to assess the risk. After providing an outline of the safety assessment procedure for the operational problems of system, safety assessment example is presented, providing details on the fault tree of operational accident, safety assessment, and risk measures.