• Title/Summary/Keyword: Factor of Safety

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Assessment of Structural Safety of Buried Water Mains (매설관의 구조적 안전성 평가에 관한 연구)

  • Bae, Chul-Ho;Kim, Ju-Hwan;Kim, Jung-Hyun;Hong, Sung-Ho;Lee, Kyung-Jae
    • Journal of Korean Society of Water and Wastewater
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    • v.21 no.2
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    • pp.151-164
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    • 2007
  • Criteria for rehabilitation priority are discussed to evaluate structural stability of deteriorated water transport and transmission pipes, in this study. For the purposes, safety factor is introduced and estimated by measuring tensile strength and by analyzing stress caused by the internal-external loads working on buried pipe body. Related informations are surveyed and collected under various conditions in the fields by digging out and the structural stability is assessed. In the evaluation results of structural safety, it is shown that steel pipe is more affected by external load than internal load. The average external load is estimated as $53.7kg/cm^2$ and total hoop stress is estimated by $2676.5kg/cm^2$. Also, Poisson effect into longitudinal direction due to internal and external loads is most influential on hoop stress. The calculated safety factors of hoop stress are ranged from 0.7 to 5.2 with average value of 2.1, considering a bending stress to longitudinal direction. The decision of rehabilitation priority by safety factors show that structural safety of CIP sample 1(S1) was assessed at the lowest order with safety factor value, 0.7 and that of DI sample 15(S15) was evaluated as the most stable in structural aspect.

A Diagnostic Study of safety education in elementary schools based on PRECEDE Model (PRECEDE 모형을 이용한 일부 초등학교 안전교육의 진단적 연구)

  • 백경원;이명선
    • Korean Journal of Health Education and Promotion
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    • v.18 no.1
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    • pp.35-47
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    • 2001
  • As the complexity of the our environment is further complicated by advancements in industry and increase in vehicle traffic flow, the incidents of injury causing accidents are on the rise. Consequently, there is increasing emphasis on the importance of systematic and continual safety education for injury preventive behaviors. This study investigates safety related problems of elementary school students based on the PRECEDE model, proposed by Green et al.(1980 Green), to comprehensively identify the requirements of school safety education. The identified requirements were used to diagnose the current state of elementary school safety education through the analysis of multidimensional factors. A questionnaire survey was conducted on 594 sixth grade students from randomly selected 4 schools in Seoul to examine their injury preventive behaviors and to determine the educational diagnosis variables that affect it. The duration of the survey was 3 weeks starting from April 12, 1999 to May 8, 1999. A summary of the survey results are presented below; 1. Situations in which accidents have occurred were, in their order of frequency, ‘during play or sports activities within the school grounds’ was most frequent at 59.6%, ‘during play on local streets’ at 49.5%, and ‘traffic accidents’ at 41.6%. 2. Categorization of the injury preventive behavior showed that ‘not playing at high traffic flow locations such as streets and construction sites’ had the higher level of observance, while ‘wearing of helmets and joint protection devices during playing’ was least observed. 3. Considering injury preventive behaviors in relation to educational diagnosis variables indicated, for predisposing factors, lower ‘perception to injury accidents’ (p〈0.001) combined with higher ‘concerns for injury accidents’(p〈0.001), ‘practice of preventive behavior’(p〈0.001), and ‘the level of safety knowledge’(p〈0.001) resulted in significantly higher observance of injury preventive behaviors. For enabling factors, higher ‘perceived level of the school safety education’ (p〈0.001) and ‘availability of safety education resources’(p〈0.01) indicated significantly higher observance of injury preventive behaviors. For the reinforcing factor, frequent exposure to ‘safety education brochure’ (p〈0.01) and ‘audio-visual material for safety education’(p〈0.01) combined with more ‘regional safety education’ (p〈0.01), ‘home safety education’ (p〈0.01), ‘school safety education’(p〈0.001), and, ‘parents’ observance of preventive behaviors' (p〈0.001) showed significantly higher observance of injury preventive behaviors. 4. An analysis of the factors that affect injury preventive behaviors showed that the enabling factor ‘awareness of school safety education’ had the highest correlation with injury preventive behaviors followed by factors, in their order of significance, ‘practice of preventive behavior’, ‘perception to injury accidents’, ‘level of safety knowledge’, ‘parents’ observances of preventive behaviors', and ‘concerns for injury accidents.’

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Hemophilia B (factor IX deficiency) in a Labrador retriever dog

  • Kim, Jun-Hwan;Noh, Dong-Ho;Song, Ru-Hui;Lee, Da-Mi;Cho, Ho-Seong;Yu, Do-Hyeon;Park, Jin-Ho;Park, Chul
    • Korean Journal of Veterinary Service
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    • v.34 no.2
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    • pp.191-193
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    • 2011
  • A 3-month-old intact male, Labrador retriever was presented with the history of coagulopathy and anemia. The results of initial screening tests of the hemostatic system yielded a tentative diagnosis of hemophilia. Activated partial thromboplastin time (APTT) was distinctly prolonged (106 seconds) and prothrombin time (PT) was not detected due to markedly prolonged test time. Whole blood transfusions (20 me l/kg body weight) were carried out prior to assays of coagulation factor. After transfusion, the patient recovered well and hemorrhage ceased. Blood samples were assessed for coagulation factor activity. The patient showed markedly low factor IX coagulation activity (5%, reference range: 7~140%) and was diagnosed with hemophilia B. After recovery, the patient was discharged from the hospital. However, 4 months later the patient was re-hospitalized for recurrence of the initial symptoms. The owner did not want to pursue further treatment and the patient died of respiratory distress two days later.

Survey and Analysis of Stakeholder Opinions on the Establishment Procedure of Safety Inspection System for Highway Construction Clients (고속도로 건설공사 발주자의 안전점검 체계구축 절차에 관한 이해관계자 설문조사 및 분석)

  • Eung Ho Park;Su Dong Lee;Kihyo Jung
    • Journal of the Korea Safety Management & Science
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    • v.25 no.4
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    • pp.57-65
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    • 2023
  • The public safety management guidelines were introduced in 2019 and continue to be dedicated to advancing comprehensive measures for public safety management, with a primary focus on prioritizing the safety and well-being of the public within governmental institutions. To achieve this goal, our previous study developed a establishment procedure of risk assessment-based safety inspection system for public institutions that order construction projects and applied it to highway construction projects to evaluate its effectiveness. To enhance the practicality of the establishment procedure, it is essential to collect and analyze feedback from stakeholders regarding its performance and suitability. This study conducted a survey involving 200 participants who had experience with the establishment procedure, and performed statistical analyses to evaluate its performance and applicability. The survey results indicated that the participants reported a high level of satisfaction (scoring 4 and above on a 5-point Likert scale) in several areas: specialization of safety inspection items for different types of work (with a satisfaction rate of 65%), the evaluation process for safety ratings (64.5%), and their willingness to recommend the procedure to other institutions (75.5%). In the factor analysis with Varimax rotation, two factors emerged: (1) a specialization factor related to safety inspection items, and (2) a grading factor associated with safety evaluation results. Regression analyses of these factors unveiled significant positive relationships with improvements in safety and health performance, including the prevention of fatal accidents, heightened safety responsibility, and raised safety inspection standards. The establishment procedure of safety inspection system developed in our previous study can play a crucial role in reducing accidents resulting in fatalities and injuries at construction sites, ultimately contributing to a safer working environment for all involved parties.

A STATISTICAL APPROACH FOR DERIVING KEY NFC EVALUATION CRITERIA

  • Kim, S.K.;Kang, G.B.;Ko, W.I.;Youn, S.R.;Gao, R.X.
    • Nuclear Engineering and Technology
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    • v.46 no.1
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    • pp.81-92
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    • 2014
  • This study suggests 5 evaluation criteria (safety and technology, environmental impact, economic feasibility, social factors, and institutional factors) and 24 evaluation indicators for a NFC (nuclear fuel cycle) derived using factor analysis. To do so, a survey using 1 on 1 interview was given to nuclear energy experts and local residents who live near nuclear power plants. In addition, by conducting a factor analysis, homogeneous evaluation indicators were grouped with the same evaluation criteria, and unnecessary evaluation criteria and evaluation indicators were dropped out. As a result of analyzing the weight of evaluation criteria with the sample of nuclear power experts and the general public, both sides recognized safety as the most important evaluation criterion, and the social factors such as public acceptance appeared to be ranked as more important evaluation criteria by the nuclear energy experts than the general public.

Evaluation of a New Workplace Protection Factor―Measuring Method for Filtering Facepiece Respirator

  • Sun, Chenchen;Thelen, Christoph;Sanz, Iris Sancho;Wittmann, Andreas
    • Safety and Health at Work
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    • v.11 no.1
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    • pp.61-70
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    • 2020
  • Background: This study aims to assess whether the TSI PortaCount (Model 8020) is a measuring instrument comparable with the flame photometer. This would provide an indication for the suitability of the PortaCount for determining the workplace protection factor for particulate filtering facepiece respirators. Methods: The PortaCount (with and without the N95-CompanionTM) was compared with a stationary flame photometer from Moores (Wallisdown) Ltd (Type 1100), which is a measuring instrument used in the procedure for determining the total inward leakage of the particulate filtering facepiece respirator in the European Standard. Penetration levels of sodium chloride aerosol through sample respirators of two brands (A and B) were determined by the two measuring systems under laboratory conditions. For each brand, thirty-six measurements were conducted. The samples were split into groups according to their protection level, conditioning before testing, and aerosol concentration. The relationship between the gauged data from two measuring systems was determined. In addition, the particle size distribution inside the respirator and outside the respirator was documented. Linear regression analysis was used to calculate the association between the PortaCount (with and without the N95-CompanionTM) and the flame photometer. Results: A linear relationship was found between the raw data scaled with the PortaCount (without N95-CompanionTM) and the data detected by the flame photometer (R2 = 0.9704) under all test conditions. The distribution of particle size was found to be the same inside and outside the respirator in almost all cases. Conclusion: Based on the obtained data, the PortaCount may be applicable for the determination of workplace protection factor.

Plans for establishing a database for Managing Railway System Safety (철도시스템 안전관리를 위한 데이터베이스 구축 방안 연구)

  • Hong Seon-Ho;Kim Sang-Ahm
    • Proceedings of the KSR Conference
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    • 2005.11a
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    • pp.605-611
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    • 2005
  • System safety management to secure complicated system safety such as railway and nuclear includes various factors. Those are prevention of accidents, faults management, human factor, men-machine relation, organization factor, safety culture, quality/quantity safety performance goal, and safety regulations. To manage them, it is required that database which is based on most analysis is established. Therefore system safety could be controlled. This research defines data required to safety management, and that is aimed at deriving plans in order to establish them as database. To accomplish that, safety information management of other systems such as aviation and marine is reviewed. Also, the present conditions of available data in the filed of domestic railway are analysed, and then it provides plans for. establishing database to build up advanced railway system safety information management systems.

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Dynamic Factor of Safety Calculation of Slope by Nonlinear Response History Analysis (비선형 응답이력해석을 통한 사면의 동적 안전계수 계산)

  • Lee, Yonghee;Kim, Hak-Sung;Ju, Young-Tae;Kim, Daehyeon;Park, Heon-Joon;Park, Duhee
    • Journal of the Korean Geotechnical Society
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    • v.37 no.9
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    • pp.5-12
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    • 2021
  • Pseudo-static slope stability analysis method is widely used in engineering practice to calculate the seismic factor of safety of slope subjected to earthquake ground motions. Although the dynamic analysis method is well recognized to have the primary advantage of simulating the stress-strain response of soils, it is not often used in practice because of the difficult in estimating the factor of safety. In this study, a procedure which utilizes the dynamic analysis method to extract the transient dynamic factor of safety is devleoped. This method overcomes the major limitation of the pseudo-static method, which uses an empirically determined seismic coefficient to derive the factor of safety. The proposed method is applied to a slope model and the result is compared with that of the pseudo-static method. It is shown that minimum dynamic factor of safety calculated by the dynamic analysis is slightly larger than that determined from the pseudo-static method. It is also demonstrated that the dynamic factor of safety becomes minimum when the horizontal seismic coefficient and horizontal average acceleration are maximum.

Assessment of Rock Slope Stability and Factor Analysis with a Consideration of a Damaged Zone (손상대를 고려한 암반사면 안정성 평가 및 인자분석)

  • Kim, Jin-Soo;Kwon, Sangki;Cheon, Dae-Sung;Park, Eui-Seob
    • Tunnel and Underground Space
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    • v.24 no.3
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    • pp.187-200
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    • 2014
  • After excavation or blasting, rock properties within an excavation damaged zone can be perpetually weakened on account of stress redistribution or blasting impact. In the present study, the excavation damaged zone is applied to a rock slope. The objective of this research is to compare the mechanical stability of the rock slope depending on the presence of the damaged zone using 2-dimensional modeling and analyze factors affecting factor-of-safety. From the modeling, it was founded that the mechanical stability of the rock slope is significantly dependent on the presence of the damaged zone. In particular, factor-of-safety with a consideration of the damaged zone decreased by approximately 49.4% in comparison with no damaged zone. Factor analysis by fractional factorial design was carried out on factor-of-safety. It showed that the key parameters affecting factor-of-safety are angle of the slope, cohesion, internal friction angle and height.

The Comparative Study on Safety Factors at Elevator Management System Operation (승강기 관리시스템 운영 시 안전요소에 관한 비교연구)

  • Park, Joo-Bong;Shin, Seung-Jung
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.14 no.6
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    • pp.159-162
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    • 2014
  • Recently, from 2008 to 2012, there are many of elevator safety patents from patent office survey. In this paper, we analyzed the elevator safety patent from 2009 to 2013, found out safety factor is safety control, emergency stop equipment and door opening equipment. Through reliability statistics, we defined the most important things for safety elevator factor is this three things, studied the reason about many patents. Finally, we propose the Kinect Scada elevator system for prevention safety accident.