• Title/Summary/Keyword: Factor of Safety

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The study on factor and model through error analysis to equipment operation (Focused on the Semiconductor industry) (설비 운영의 에러 분석을 통한 인자 및 모델연구 -반도체 산업중심-)

  • Yoon, Yong-Gu;Park, Peom
    • Proceedings of the Safety Management and Science Conference
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    • 2009.11a
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    • pp.187-201
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    • 2009
  • Semiconductor industry is based on equipment industry and timing industry. In particular, semiconductor process is very complex and as semiconductor-chip width tails and is becoming equipment gradually more as a high technology. Equipment operation is primarily engaged in semiconductor manufacturing (engineers and operator) of being conducted by, equipment errors have also been raised. Equipment operational data related to the error of korea occupational safety and health agency were based on data and production engineers involved in the operator's questionnaire was drawn through the error factor. Equipment operating in the error factor of 9 big item and 36 detail item detailed argument based on the errors down, and 9 big item the equipment during operation of the correlation error factor was conducted. Each of the significance level was correlated with the tabulation and analysis. Using the maximum correlation coefficient, the correlation between the error factors to derive the relationship between factors were analyzed. Facility operating with the analysis of error factors (big and detail item) derive a relationship between the model saw. The end of the operation of the facility in operation on the part of the two factors appeared as prevention. Safety aspects and ergonomics aspects of the approach should be guided to the conclusion.

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Derivation of the Risk-Safety Factor Relation for Optimal Storm Sewer Design in Urban Area (도시지역의 최적 배수관망 설계를 위한 Risk Safety Factor 관계의 설정)

  • Kim, Mun Mo;Lee, Won Hwan;Cho, Won Cheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.12 no.4
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    • pp.129-134
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    • 1992
  • This paper presents the relation between risk and safety factor for optimal storm sewer design in urban area. For reliability analysis of the storm sewer, uncertainty of the various parameters of constituting equation determining the capacity and load of storm" sewer is considered and risk is determined. In this study, reliability analysis method is applied to Seongsan detention reservoir basin which area is $381,000m^2$ Darcy-Weisbach equation is used for determining capacity of the storm sewer and rational formula is used for determining load. Safety factor representing ratio of the sewer capacity and design flowrate is calculated, and relating with risk. Then risk and safety factor with return period is obtained and it is used for optimal design of storm sewer.

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A Study on Improvement of Strength Safety Factor for K55A1 APU Engine Mounts (자주포 보조동력장치 엔진 마운트 강도안전율 향상에 관한 연구)

  • Kim, Byung Hyun;Seo, Jae Hyun;Park, Young Il;Kim, Yong Wook;Kim, Byung Ho
    • Journal of the Korea Institute of Military Science and Technology
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    • v.19 no.3
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    • pp.281-287
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    • 2016
  • The purpose of this study is to analyze the vibration characteristics and develop a mounting which can improve the strength safety factor to replace the high failure rate APU(auxiliary power unit) imported metal mounts with rubber mount that can be domestically produced. For this study, we analyzed in 3 kinds of rubber mounts hardness for the natural frequency to avoid the average excited frequency of the APU. In addition, allowed vibration acceleration of rubber mount confirmed to 90.8 g by adding a strength safety factor. To assure the validity of the design, we measure the vibration acceleration equipped with a metal mount and rubber mount 2 species(Hs 50 and 60). As a result, the proposed design method in this study is reasonable because the rubber mounts is excellent strength safety factor and vibration transmissibility than metal mounts.

Research on Risk Assessment of Lithium-ion Battery Manufacturing Process Considering Cell Materials (셀소재를 고려한 리튬2차전지 제조공정 위험성 평가 방법 연구)

  • Kim, Taehoon
    • Journal of the Korean Society of Safety
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    • v.37 no.2
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    • pp.76-87
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    • 2022
  • Lithium-ion batteries (LIBs) have attracted much interest for their high energy density (>150 mAh/g), high capacity, low self-discharge rate, and high coulombic efficiency. However, with the successful commercialization of LIBs, fire and explosion incidents are likely to increase. The thermal runaway is known as the major factor in battery-related accidents that can lead to a series of critical conditions. Considering this, recent studies have shown an increased interest in countering the safety issues associated with LIBs. Although safety standards for LIB use have recently been formulated, little attention has been paid to the safety around the manufacturing process for battery products. The present study introduces a risk assessment method suitable for assessing the safety of the LIB-manufacturing process. In the assessment method, a compensation parameter (Z-factor) is employed to correctly evaluate the process's safety on the basis of the type of material (e.g., metal anode, liquid electrolyte, solid-state electrolytes) utilized in a cell. The proposed method has been applied to an 18650 cell-manufacturing process, and three sub-processes have been identified as possibly vulnerable parts (risk index: >4). This study offers some crucial insights into the establishment of safety standards for battery-manufacturing processes.

Concept Design of Fire Safety Module for SV20 Service in the Korean e-Navigation System

  • Kim, Byeol;Moon, Serng-Bae;Hwang, Kwang-Il
    • Journal of Navigation and Port Research
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    • v.42 no.5
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    • pp.323-330
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    • 2018
  • The Korean e-Navigation system is a Korean approach to correspond with implementation of IMO e-Navigation. It provides five services, among them SV20 service, a ship remote monitoring system that collects and processes sensor information related to fire, navigation, and seakeeping performance safety. The system also detects abnormal conditions such as fires, capsizing, sinking, navigation equipment failure during navigation, and calculates the safety index and determines the emergency level. According to emergency level, it provides appropriate emergency response guidance for the onboard operator. The fire safety module is composed of three sub-modules; each module is the safety index sub-module, the emergency level determination sub-module and emergency response guidance sub-module. In this study, operational concept of the fire safety module in SV20 service is explained, and fire safety assessment factors are estimated, to calculate the fire safety index. Fire assessment factors included 'Fire detector position factor,' 'Smoke diffusion rate factor,' and 'Fire-fighting facilities factor.'

SAFETY EVALUATION OF SUNSCREENS (I) ; CORRELATION BETWEEN SUN PROTECTION FACTOR AND SKIN IRRITATION

  • Suh, Soo-Kyung;Kim, Jong-Won;Park, Ju-Young;Seo, Kyung-Won;Park, Chang-Won;Kim, Kyu-Bong;Kim, Kwang-Jin;Kim, Jong-Min;Lee, Sun-Hee
    • Proceedings of the Korean Society of Toxicology Conference
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    • 2002.05a
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    • pp.138-138
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    • 2002
  • In recent years, the safety of sunscreens has been challenged based on the reports of its adverse effect on users; dermatitis, allergic contact dermatitis, photoallergic contact dermatitis. To investigate a correlation between sun protection factor (SPF) and the safety of sunscreens, we measured in vitro SPF index using homosalate as a standard and examined the toxicity tests on cosmetics; primary and cumulative skin irritation tests, ocular irritation test, and skin sensitization test.(omitted)

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Study on Soil Parameters and Two Dimensional Analysis in Slope Stability (사면안정 2차원해석과 토질정수에 관한 연구)

  • 김경진;김규문;박일철
    • Journal of the Korean Professional Engineers Association
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    • v.18 no.3
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    • pp.21-27
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    • 1985
  • Earthen mass located beneth a sloping group surface, whether natural or manmade, have a tendency to move downward and outward under the influence of gravity. Unless this tendency is suitably counteracted by the Shearing resistances within the mass, a landslide occurs. Avoiding such instabilities is a major concern of the geotechnical engineer. The shearing behavior of a soil is determined empirically, i.e., by field tests or laboratory tests. This results are applied to the slope stability analysis. The factor of safety for slope stability analysis is much more sensitive to the choice of strength parameters as interpreted from soil tests than to the choice of the computational method of analysis. This paper was investigated the influence of the change in the factor of safety due to a change in one of the parameters, relative to the total change in the factor of safety due to change in all parameters. A conclusion may be reached with respect to the required precision definition of the different variables to limit uncertainties in the factor of safety to tolerable levels.

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A study on the Importance of Risk Factor for Falling Accident in Construction Site (건설현장 추락재해의 위험요인 중요도 분석 연구)

  • Kim, Do-Su;Shin, Yoon-Seok
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.11a
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    • pp.63-64
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    • 2018
  • The construction industry is one of the most prolific disaster-prone industries, particularly those that suffer from falling disasters compared to other industries. The safety accident at the construction site leads to social problems caused by massive loss of life and property, so it needs to be extra careful. The reason why falls are the most frequent accidents of the types of construction accidents is due to the analysis of the risk factors of safety accidents and the development of various construction methods. Therefore, in this study, the accident case for the fallen victims of construction site was analyzed and the risk factor was selected. Based on the safety expert survey, an importance analysis was performed. In conclusion, this study analyzes various risk factors that affect the occurrence of falls, identifies the importance of each factor, and presents basic data for safety accident prevention activities.

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Development of limit equilibrium method as optimization in slope stability analysis

  • Mendjel, D.;Messast, S.
    • Structural Engineering and Mechanics
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    • v.41 no.3
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    • pp.339-348
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    • 2012
  • The slope stability analysis is usually done using the methods of calculation to rupture. The problem lies in determining the critical failure surface and the corresponding factor of safety (FOS). To evaluate the slope stability by a method of limit equilibrium, there are linear and nonlinear methods. The linear methods are direct methods of calculation of FOS but nonlinear methods require an iterative process. The nonlinear simplified Bishop method's is popular because it can quickly calculate FOS for different slopes. This paper concerns the use of inverse analysis by genetic algorithm (GA) to find out the factor of safety for the slopes using the Bishop simplified method. The analysis is formulated to solve the nonlinear equilibrium equation and find the critical failure surface and the corresponding safety factor. The results obtained by this approach compared with those available in literature illustrate the effectiveness of this inverse method.

Probabilistic Safety Assessment of Nuclear Power Plants Using Alpha Factor Method for Common Cause Failure (알파모수 공통원인고장 평가 기법을 활용한 원자력발전소 안전성 평가)

  • Hwang, Seok-Won
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.10 no.1
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    • pp.51-55
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    • 2014
  • Based on the results of Probabilistic Safety Assessment(PSA) for a Nuclear Power Plant (NPP), Common Cause Failure(CCF) events have been recognized as one of the main contributors to the risk. Also, the CCF data and estimation method used in domestic PSA models have been pointed out as an issue with respect to the quality. The existing method of MGL and non-staggered testing even widely used were considered conservative in estimating the safety and had a limited capability in uncertainty analyses. Therefore, this paper presents the CCF estimation using a new generic data source and Alpha factor method. The analyses showed that Alpha factor and staggered method are effective in estimating the CCF contribution and risk insights of reference plant. This method will be a common bases for the optimization of new design for the construction plants as well as for the updating of safety assessment on the operating nuclear power plants.