• Title/Summary/Keyword: Characteristic Factor of Safety

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Analysis Techniques for Accident Causes of Subcontract Work at Construction Site (전문 건설공사 재해원인 분석 기법에 관한 연구)

  • Son, Ki-Sang;Rhee, Kyung-Yong;Gal, Won-Mo
    • Journal of the Korean Society of Safety
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    • v.24 no.5
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    • pp.34-42
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    • 2009
  • There are many accident causes related to even an accident. As well four(4) stepped causes of one accident at construction sites are analyzed in the study. First, eleven(11) cause factors are set up at each step such as policy level, management, indirect, direct level which are discussed and determined by field experts with 15year experience or more. Therefore, one direct cause occurred in construction site can be connected to the previous cause than in direct and management, and policy problem of previous management. These questionnaires results are analyzed with three different methods such as weighing level by Delphi technique, correlation analysis, critical pass method. Three different methods show their characteristic to see which subcontract work is more dangerous or not. Subcontract or at a construction site can be use the above three different cases as they need at their site in order to make more effective countermeasures.

A Study on the Typology of Agricultural Reservoir for Effective Safety Inspection Systems (효율적인 안전진단 체계 수립을 위한 농업용 저수지 유형화 연구)

  • Lee, Chang Beom;Jung, Nam Su;Park, Seong Ki;Jeon, Sang Ok
    • Journal of The Korean Society of Agricultural Engineers
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    • v.57 no.5
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    • pp.89-99
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    • 2015
  • In this research, 1,032 data of precise safety inspection from 2004 to 2013 are gathered and constructed for finding effective safety inspection systems. Items are extracted from constructed data and factors for typology are decided with statistical method such as principle component analysis and cluster analysis. For factor decision, we extruded independent characteristics such as morphological and geographical characteristic, and deleted items which can be expressed by combination of independent characteristics. Four factors such as total storage, watershed ratio, levee length ratio, and spillway length ratio are extracted in this process. In cluster analysis, levee length ratio is excluded because it is not separated as cluster. Finally nine types of agricultural reservoir are extruded by total storage, watershed ratio, and spillway length ratio with frequency analysis.

A Study on the Methods of Fire-Safety in Cultural Property Wooden Buildings (목조 문화재 건축물의 화재 방재를 위한 조사 연구)

  • Chang, Hyung-Soon;Cho, Won-Seok;Kim, Heung-Gee
    • Journal of the Korean Institute of Rural Architecture
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    • v.10 no.4
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    • pp.25-32
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    • 2008
  • The prevention of disasters in cultural property is very important management and historical duties. The reason can't be measured values with monetary scale of our contemporary. Therefore, this paper was considered fire-safety as one of terrible threat-disasters about the wooden buildings. This research deal with 47 cases cultural property wooden building by whole investigation(field survey and interview) in Gangnung province. The most buildings have basic fire extinguisher; ABC powder. A few buildings are rarely installed fire extinguishing equipments; outdoor fire hydrant, heat sensor, ground sprinkler, CO2-hose-reel. But these state is very insufficient for the fire-safety in cultural property wooden buildings. Specially as particular attention in province, forest fire of regional characteristic have close relation with cultural property fire. The majority of factor against forest and building fire is to provide monitoring and security system; CCTV, Fence, Sensor, Alarm and paid guard man against incendiary. Ultimately it is necessary to construct comprehensive disaster prevention system with the organic cooperation such as National Emergency Management Agency, Cultural Heritage Administration, Forest Service, local government officials and regional citizen.

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A Study on the Design of decision logic for n Tire Pressure Monitoring System (타이어 공기압 모니터링 시스템의 판단 로직 설계에 관한 연구)

  • Kim Byeong-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.3
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    • pp.285-290
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    • 2006
  • In a Vehicle, Safety is the most important factor for drivers. It is well known that tire pressure lower than normal reduces the safety of the vehicle. In a consideration of active safety, tire pressure monitoring system is absolutely required. Tire pressure monitoring using in-tire pressure sensors with an RE data link have proven to be best approach to measuring tire pressure over the widest range of operating conditions. In this paper, we describe the parameters of TPMS, the characteristic of tire pressure and temperature compensation. These are the main factors to design the decision logic. We will show the guidelines for TPMS logic development considering environment variables and vehicle conditions.

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A Study on the Interior Environmental Planning Factors for Improving Safety and Security in Early Children Facilities (안전성 향상을 위한 유아시설 실내환경 계획요인에 관한 연구)

  • Byun, Gi-Dong;Kwon, Ju-Yeong;Ha, Mi-Kyoung
    • Korean Institute of Interior Design Journal
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    • v.24 no.2
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    • pp.197-205
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    • 2015
  • Recently in most homes, children are mostly cared in early childhood education facilities. However, the increased number of safety accidents on children cared in such facilities has become a social issue. For that, the purpose of this study is to suggest interior environmental planning elements to improve safety level of early childhood education facilities. This study was carried out by performing literature review analysis and survey. First, in total of 42 environmental planning elements that can be applied domestically were derived from analyzing safety related guidelines for children facilities located both domestically and internationally then a survey was carried out targeted for teachers and staffs in the facilities on importance of the factors. The results of this study are as followings. First, it is required to intensify the level of safety related training for teachers and staffs in the facilities including better treatment for them. Second, the necessity of safety environment by each space in such facilities is required to be approached upon the level of child activities. Third, facilities planning and finalizing planning are important for improving safety of early childhood education facilities. Forth, from factor analysis on the extracted environmental planning elements that are considered as important by the teachers from both day care centers and kindergartens, they were categorized in 5 groups including 'collision and fall prevention plan', 'physical characteristic consideration plan', 'evacuation safety plan', 'lock security plan' and 'outer control plan'. It is fair to say that constructing a better safety environment for children can be achieved by the environmental planning factors by this study.

The Influence of Fitting Parameters on the Soil-Water Characteristics Curve in Stability Analysis of an Unsaturated Natural Slope (불포화 자연사면의 안정해석시 흙-함수특성곡선 맞춤계수의 영향)

  • Kim, Jae-Hong;Yoo, Yong-Jae;Song, Young-Suk
    • The Journal of Engineering Geology
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    • v.31 no.2
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    • pp.165-178
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    • 2021
  • The influence of Soil-Water Characteristic Curve (SWCC) fitting parameters for an unsaturated natural slope was evaluated through seepage and slope stability analysis as a function of rainfall. Soil samples were collected from the study area in Jirisan National Park and the physical and mechanical characteristics of unsaturated soil layers were measured in laboratory tests. The saturation depth was calculated via seepage analysis by changing fitting parameters α, the parameter related to the Air Entry Value (AEV) and n, the parameter related to the slope of the SWCC in the range of natural conditions. Slope stability analysis using the limit equilibrium method considered the calculated depth of saturation. Results from seepage analysis for various rainfall conditions indicate the saturation depth in the soil layer suddenly increased as the fitting parameter α decreased; the saturation time for the entire soil layer also decreased. Slope stability analysis considering the calculated depth of saturation shows that the slope safety factor rapidly decreased as the fitting parameter α decreased, whereas the variation in slope safety factor was very small when n increased. Hence, fitting parameter α has a large effect on saturation depth during rainfall and therefore on slope stability, whereas slope stability is relatively unaffected by the fitting parameter n.

Filtration Rates of Juvenile Purple Clam, Saxidomus purpuratus (Sowerby) Feeding on Red Tide Dinoflagellates

  • Lee, Chang-Hoon;Moon, Seong-Dae;Sung, Chan-Gyoung
    • The Korean Journal of Malacology
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    • v.28 no.4
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    • pp.349-359
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    • 2012
  • The purpose of this study is to compare the clearance rate (CR) and intake rate (IR) of juvenile purple clam, Saxidomus purpuratus when feeding on different unialgal diet of red tide dinoflagellates (RTDs), and to know what is the most important cell characteristic of RTDs to cause the differences in feeding parameters. Experiments were performed to measure the CR and IR of juvenile S. purpuratus as a function of algal concentration when food was either the standard food, Isochrysis galbana or one of 9 RTDs. Patterns of CR with increasing algal concentration were similar among different RTDs. The highest $C_{max}$ was observed when S. purpuratus was feeding on A. affine, while the lowest on C. polykrikoides. The patterns of IR with increasing algal concentration were also similar among different RTDs. However, there were great differences in the maximum value of IR ($I_{max}$) among different RTDs. The highest $I_{max}$ was observed when S. purpuratus was feeding on A. carterae, while the lowest on G. catenatum. Some RTDs similar in size showed different $C_{max}$. Other RTDs different in size showed similar $I_{max}$. Life form of each RTD affected significantly the $I_{max}$, which was higher for single-celled RTDs than chain-forming RTDs. There were no significant differences in feeding parameters between toxic and nontoxic RTDs. Moreover, a toxic dinoflagellate, A. carterae recorded the highest $I_{max}$ among RTDs. The most important characteristic of RTD as a factor affecting the feeding rate of S. purpuratus was life form, not size or toxicity of RTD species.

A Study on Shaft Dynamic Characteristic for G/T 250TON Double-Ended Car-Ferry (G/T 250톤 양방향 차도선 축계의 동특성에 관한 고찰)

  • Kang, Byoung-Mo;Oh, Young-Cheol;Bae, Dong-Gyun;Seo, Kwang-Cheol;Ko, Jae-Yong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.21 no.1
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    • pp.83-90
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    • 2015
  • The car ferry operating between the mainland and the island plays an important role on transportation of goods and passengers. Therefore, the improvement of efficiency and safety as well as economic factor are importantly considered in the development process of car ferry. Double-ended car ferry is already popularized because of its economic feasibility and convenience for passenger in Europe and developed countries, and the demand is booming in domestic. In this paper, dynamic characteristics of propeller shaft and strength in double-ended car ferry are analyzed using campbell diagram and modal analysis. Based on the analysis of dynamic characteristics, resonant phenomenon and critical speed are stable when occurring the propeller shaft vibration due to forward and reverse propeller shaft working.

Evaluation of Waist Circumference Cut-off Values as a Marker for Fatty Liver among Japanese Workers

  • Abe, Naomi;Honda, Sumihisa;Jahng, Doosub
    • Safety and Health at Work
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    • v.3 no.4
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    • pp.287-293
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    • 2012
  • Objectives: Metabolic syndrome has received attention as a risk factor for cardiovascular disease, with particular importance attached to visceral fat accumulation, which is associated with lifestyle-related diseases and is strongly correlated with waist circumference. In this study, our aim is to propose waist circumference cut-off values that can be used as a marker for fatty liver based on a sample of workers receiving health checkups in Japan. Methods: This study was conducted in a total of 21,866 workers who underwent periodic health checkups between January 2007 and December 2007. The mean age of the subjects was 47.4 years for men (standard deviation [SD]: 8.0) and 44.7 years for women (SD: 6.9). Evaluation included abdominal ultrasound and measurement of waist circumference, body mass index, fasting blood glucose, triglycerides, high-density lipoprotein cholesterol, and blood pressure. Results: Based on receiver operating characteristic curve analysis, the optimal waist circumference cut-off values were shown as 85.0 cm (sensitivity 0.72, specificity 0.69) for men and 80.0 cm (sensitivity 0.75, specificity 0.78) for women. Conclusion: Abdominal ultrasound is the most efficient means of diagnosing fatty liver, but this examination seldom occurs because the test is not routinely performed at workers' health checkups. In people found to have a high risk of fatty liver, recommendations can be made for abdominal ultrasound based on the waist circumference cut-off values obtained in this study. That is, waist circumference can be used in high risk individuals as an effective marker for early detection of fatty liver.

Experimental Investigation on Combustion Performance of a Pintle Injector Engine with Double-row Rectangular Slot (핀틀 인젝터 Rectangular Slot 2열 형상에 따른 연소성능에 관한 연구)

  • Ryu, Hobin;Yu, Isang;Kim, Wanchan;Shin, Donghae;Ko, Youngsung;Kim, Seonjin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.21 no.3
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    • pp.25-33
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    • 2017
  • In this study, combustion tests were performed to investigate combustion performance of a pintle injector engine with double row rectangular slot which uses kerosene and liquid oxygens as propellants. The double row rectangular slot was designed to improve the combustion performance of a pintle engine with a single row and the blockage factor was changed from 0.7 to 1.0. The main design parameters of the double row were distance between rows, area ratio and aspect ratio. The characteristic velocity efficiency was measured from 92.4 to 96.9 percentage for double row but 86.8 percentage for single row. It showed the highest combustion performance at the BF 0.85.