• Title/Summary/Keyword: factor of safety

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A Three Dimensional Study on the Probability of Slope Failure(II) (사면(斜面)의 삼차원(三次元) 파괴확률(破壞確率)에 관(關)한 연구(硏究)(II))

  • Kim, Young-Su;Tcha, Hong-Jun;Jung, Sung-Kwan
    • Journal of Industrial Technology
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    • v.3
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    • pp.53-63
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    • 1983
  • The probability of failure is used to analyze the reliability of three dimensional slope failure, instead of conventional factor of safety. The strength parameters are assumed to be normal variated and beta variated. These are interval estimated under the specified confidence level and maximum likelihood estimation. The pseudonormal and beta random variables are generated using the uniform probability transformation method according to central limit theorem and rejection method. By means of a Monte-Carlo Simulation, the probability of failure is defined as; Pf=M/N N : Total number of trials M : Total number of failures Some of the conclusions derived from the case study include; 1. Three dimensional factors of safety are generally much higher than 2-D factors of safety. However situations appear to exist where the 3-D factor of safety can be lower than the 2-D factor of safety. 2. The F3/F2 ratio appears to be quite sensitive to c and ${\phi}$ and to the shape of the 3-D shear surface and the slope but not to be to the unit weight of soil. 3. In cases that strength parameters are assumed to be normal variated and beta variated, the relationships between safety factor and the probability of failure are fairly consistent, regardless of the shape of the 3-D shear surface and the slope. 4. As the c-value is increased, the probability of failure for the same safety factor is increased and as the ${\phi}-value$ is increased, the probability of failure for the same safety factor is decreased.

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A Study on Targer Factor Value of Port State Control Inspection (항만국통제 Target Factor 선정에 관한 연구)

  • Jang, Woon-Jae;Cho, Ik-Sun;Choi, Ki-Jung;Choi, Kyong-Il;Kim, Kyung-Bok;Keum, Jong-Soo
    • Proceedings of KOSOMES biannual meeting
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    • 2009.06a
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    • pp.71-75
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    • 2009
  • This paper proposes an evaluation to Target Factor Values of Port State Control Inspections(PSCITFV) using AHP because PSCITFV is very simple methode, This AHP is the more rational and objective methode than existing TFV methode. AHP is relative measurement., but, weights should be re-calculation whenever alternative plan add. To this solve, therefore, this paper, used an absolute measurement and involved an marine casualty factor in PSCITFV, that IMO go ahead with it., Also, accomplished with evaluation some ships for the practice.

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A Study on Effect of Stabilizing Pile on Stability of Infinite Slope (무한사면의 안정성에 미치는 억지말뚝의 영향에 대한 이론적 연구)

  • Lee, Seung-Hyun;Lee, Su-Hyung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.12
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    • pp.496-503
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    • 2016
  • To analyze an infinite slope that is reinforced with stabilizing piles, the forces on the stabilizing pile were estimated by the theory of plastic deformation and the theory of plastic flow and the effects of diverse factors on the factor of safety of an infinite slope were investigated. According to the results of the analyses, the factor of the safety of the slope reinforced with stabilized piles were increased tremendously and the factor of safety decreased as the center to center distance of the stabilizing pile increased. The effect of the existence of seepage of the infinite slope with stabilizing piles on the factor of safety appears to be insignificant. Considering the formulated factor of safety of an infinite slope with stabilizing piles, the width and length of the element of the infinite slope and force on the stabilizing pile influence the factor of safety of the infinite slope with a stabilizing pile including the soil strength parameter, inclination of the slope and depth of the slope, which are important for calculating the factor of safety of a non-reinforced infinite slope. The factor of safety of an infinite slope with stabilizing piles derived from the theory of plastic deformation were increased significantly with the internal friction angle of the soil, and the minimum and the maximum factor of safety under the conditions considered in this study were 13.7 and 65.6, respectively. As the diameter of the stabilizing pile increased, the forces on the stabilizing pile also increased but the factor of safety of the infinite slope with stabilizing piles decreased due to the effects of the width and the length of the element of the infinite slope. The factor of safety of the infinite slope with stabilizing piles derived from plastic flow were much larger than that of the non-reinforced infinite slope and the factor safety of the infinite slope with a stabilizing pile increased with increasing product of the flow velocity and plastic viscosity ( ) and the factor of safety of the infinite slope with stabilizing piles decreased with increasing center to center distance of the pile.

Safety Factor Analysis of Range-Shift on Multi-Purpose Agricultural Implement Machinery (다목적 농작업 기계 변속기 부변속 안전율 분석)

  • Moon, Seok Pyo;Baek, Seung Min;Lee, Nam Gyu;Park, Seong Un;Choi, Young Soo;Choi, Chang Hyun;Kim, Yong Joo
    • Journal of Drive and Control
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    • v.17 no.4
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    • pp.141-151
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    • 2020
  • The aim of this study was to analyze the safety factor of range-shift gear pairs on multi-purpose agricultural implement machinery for an optimal design of a transmission system. Gear-strengths such as bending and contact stress and safety factors were analyzed under three load conditions: an equivalent engine torque at plow tillage, a rated engine torque, and the maximum engine torque. Root and contact safety factor were calculated to be 3.88, 5.14, 2.24, 2.11, 2.21, 0.99 and 0.78, 0.94, 0.65, 0.68, 0.84, 0.85, respectively, under equivalent engine torque condition at the plow tillage. The root and contact safety factor were calculated to be 1.91, 2.53, 1.10, 1.04, 1.07, 0.48 and 0.55, 0.66, 0.46, 0.48, 0.59, 0.59, respectively, under rated engine torque condition. The root and contact safety factor were calculated to be 1.60, 2.11, 0.92, 0.87, 0.90, 0.40 and 0.51, 0.61, 0.42, 0.44, 0.54, 0.54, respectively, under the maximum engine torque condition. The multi-purpose agricultural implement machinery could be conducted under plow tillage operation. However, gear specifications for tooth surface need modification because the gear surface would be broken at all driving conditions as safety factors are lower than 1.

The relationship between human factor and error for behavior of manufacturing industry employee (제조업근로자의 행동에 대한 인적요인 및 오류관계 연구)

  • Yoon, Yong-Gu
    • Proceedings of the Safety Management and Science Conference
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    • 2007.11a
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    • pp.107-119
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    • 2007
  • The purpose of this article is to examine the relationship between unsafe behavior, human factor and human error. For the object, several correlation analyses for those three elements were implemented. Several hypotheses for the relationship between them was suggested. The suggested hypotheses were verified by a comprehensive survey received from 132 safety manager of manufacturing industry. The conclusions were proven from the hypotheses verificaiton as belows; 1) The dependent relation items between unsafe behavior and human factor are dress protection tool, machine(equipment) and working rule have a dependent relation. 2) The dependent relation items between human factor and human error are uncommunication, control, slaps, fatigue, education, system, unmonitoring, failure. 3) The dependent relation items between human error and unsfafe behavior are decline and product/working method,failure and uncommunication have a dependent relation.

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The Influence of Self-resilience on Dietary Management in Middle School Students (중학생의 자아탄력성이 식생활관리에 미치는 영향)

  • Kim, Yunhwa
    • Korean Journal of Community Nutrition
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    • v.20 no.6
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    • pp.399-410
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    • 2015
  • Objectives: This study aims to identify self-resilience factors that drive right dietary and food safety practices in middle school students. Methods: Data was collected from 438 middle school students in Daegu using a self-administered questionnaire in December, 2013. The questionnaire consisted of 81 items with the following categories: general information, self-resilience, right dietary and food safety practices. Statistical analyses to determine frequency, average, ANOVA, factor analysis, reliability analysis, and regression analysis were performed using SPSS 21. Results: The results of factor analysis indicated that self-resilience was classified into challenge, adaptability, patience and achievement needs, and right dietary practices were sub-grouped into family meals, experience of dietary life, eco-friendly, balanced food, economy and bad food control, and food safety practices consisted of management of bacteria, hand washing and eating off a plate, safety food and food purchasing. The score of right dietary and food safety practices showed significant differences by sex, grade, and school achievement (p < 0.05). The economy factor of right dietary practices was significantly affected by the management of bacteria (p < 0.001), hand washing and eating off a plate (p < 0.001), safety food (p < 0.01), food purchasing of food safety practices (p < 0.05). The challenge factor of self-resilience significantly affected family meals, experience of dietary life, balanced food, economy, bad food control, management of bacteria, hand washing and eating off a plate, and safety food (p < 0.05). The adaptability factor of self-resilience was associated with factors such as eco-friendly, balanced food, economy, bad food control, management of bacteria, hand washing and eating off a plate, and food purchasing (p < 0.05). Conclusions: This study suggests that dietary education programs for middle school students could incorporate food safety practices, and self-resilience such as challenge, adaptability, patience and achievement needs to be effective.

Developing a Basic Scale for Workers' Psychological Burden from the Perspective of Occupational Safety and Health

  • Kim, Kyung Woo;Lim, Ho Chan;Park, Jae Hee;Park, Sang Gyu;Park, Ye Jin;Cho, Hm Hak
    • Safety and Health at Work
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    • v.9 no.2
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    • pp.224-231
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    • 2018
  • Background: Organizations are pursing complex and diverse aims to generate higher profits. Many workers experience high work intensity such as workload and work pressure in this organizational environment. Especially, psychological burden is a commonly used term in workplace of Republic of Korea. This study focused on defining the psychological burden from the perspective of occupational safety and health and tried to develop a scale for psychological burden. Methods: The 48 preliminary questionnaire items for psychological burden were prepared by a focus group interview with 16 workers through the Copenhagen Psychosocial Questionnaire II and Mindful Awareness Attention Scale. The preliminary items were surveyed with 572 workers, and exploratory factor analysis, confirmatory factor analysis, and correlation analysis were conducted for a new scale. Results: As a result of the exploratory factor analysis, five factors were extracted: organizational activity, human error, safety and health workload, work attitude, and negative self-management. These factors had significant correlations and reliability, and the stability of the model for validity was confirmed using confirmatory factor analysis. Conclusion: The developed scale for psychological burden can measure workers' psychological burden in relation to safety and health. Despite some limitations, this study has applicability in the workplace, given the relatively small-sized questionnaire.

A Study on the Safety Frame Interval of Pipe Houses in Kyungpook Region (경북지방 파이프하우스의 안전골조간격에 관한 연구)

  • 이현우;이석건
    • Journal of Bio-Environment Control
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    • v.4 no.2
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    • pp.195-202
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    • 1995
  • As the pipe houses were constructed by imitation and routine without a structural design by now, they were often destructed by a strong wind or a heavy snowfall. The purpose of this study was to provide the basic data for the safety structural design of the pipe houses in Kyungpook region to prevent meteorological disaster. It was shown that the change of frame interval according to the safety factor under the wind load was similar that under the snow load. But the safety frame interval under the snow load was approximately 0.5-0.6m greater than that under the wind load for equal safety factor. Therefore, it seemed that the maximum safety frame interval was to be decided by the snow load. The frame of the pipe houses in Seungju region was structurally stable under the design snow load in recurrence intervals of 8-15years, but was unstable in Kolyong region.

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An Analysis of Human Factor and Error for Human Error of the Semiconductor Industry (반도체 산업에서의 인적오류에 대한 인적요인과 과오에 대한 분석)

  • Yun, Yong-Gu;Park, Beom
    • Proceedings of the Safety Management and Science Conference
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    • 2007.04a
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    • pp.113-123
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    • 2007
  • Through so that accident of semiconductor industry deduces unsafe factor of the person center on unsafe behaviour that incident history and questionnaire and I made starting point that extract very important factor. It served as a momentum that make up base that analyzes factors that happen based on factor that extract factor cause classification for the first factor, the second factor and the third factor and presents model of human error. Factor for whole defines factor component for human factor and to cause analysis 1 stage in human factor and step that wish to do access of problem and it do analysis cause of data of 1 step. Also, see significant difference that analyzes interrelation between leading persons about human mistake in semiconductor industry and connect interrelation of mistake by this. Continuously, dictionary road map to human error theoretical background to basis traditional accidental cause model and modern accident cause model and leading persons. I wish to present model and new model in semiconductor industry by backbone that leading persons of existing scholars who present model of existent human error deduce relation. Finally, I wish to deduce backbone of model of pre-suppression about accident leading person of the person center.

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Neutronics analysis of JSI TRIGA Mark II reactor benchmark experiments with SuperMC3.3

  • Tan, Wanbin;Long, Pengcheng;Sun, Guangyao;Zou, Jun;Hao, Lijuan
    • Nuclear Engineering and Technology
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    • v.51 no.7
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    • pp.1715-1720
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    • 2019
  • Jozef Stefan Institute (JSI), TRIGA Mark II reactor employs the homogeneous mixture of uranium and zirconium hydride fuel type. Since its upgrade, a series of fresh fuel steady state experimental benchmarks have been conducted. The benchmark results have provided data for testing computational neutronics codes which are important for reactor design and safety analysis. In this work, we investigated the JSI TRIGA Mark II reactor neutronics characteristics: the effective multiplication factor and two safety parameters, namely the control rod worth and the fuel temperature reactivity coefficient using SuperMC. The modeling and real-time cross section generation methods of SuperMC were evaluated in the investigation. The calculation analysis indicated the following: the effective multiplication factor was influenced by the different cross section data libraries; the control rod worth evaluation was better with Monte Carlo codes; the experimental fuel temperature reactivity coefficient was smaller than calculated results due to change in water temperature. All the results were in good agreement with the experimental values. Hence, SuperMC could be used for the designing and benchmarking of other TRIGA Mark II reactors.