• Title/Summary/Keyword: Mean Factor of Safety

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A Proposed method of the Strength Calculation of Pipe Support (파이프 서포트의 내력 산정 방안)

  • 이영욱;최순주
    • Journal of the Korean Society of Safety
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    • v.16 no.1
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    • pp.59-64
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    • 2001
  • Even though there is a guideline for the required strength of pipe support in inspection, it does not mean the nominal strength which can be used for the form work design. And, Concrete Specification defines that the pipe support should be designed according to the steel design guidelines but the design details are not provided, such as buckling length and the sectional modulus, etc. For the better prediction of strength of pipe support, the slenderness ratio of support which reflects the boundary condition should be considered. In this paper, the elastic buckling formula based on the slenderness is derived. The formula contains the strength reduction factor that consider the strength deduction caused by initial lateral deformation and is 0.65 consistently regardless of boundary conditions. And the coefficient of effective buckling length is calculated from the experiment.

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Estimation of Gauge R&R by Variance Components of Measurement ANOVA (측정 ANOVA의 분산성분에 의한 게이지 R&R 추정)

  • Choi, Sung-woon
    • Journal of the Korea Safety Management & Science
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    • v.12 no.1
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    • pp.199-205
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    • 2010
  • The research proposes the three-factor random measurement models for estimating the precision about operator, part, tool, and various measurement environments. The combined model with crossed and nested factors is developed to analyze the approximate F test by degrees of freedom given by Satterthwaite and point estimation of precisions from expected mean square. The model developed in this paper can be extended to the three useful models according to the type of nested designs. The study also provides the three-step procedures to evaluate the measurement precisions using three indexes such as SNR(Signal-To-Noise Ratio), R&R TR(Reproducibility&Repeatability-To-Total Precision Ratio), and PTR(Precision-To-Tolerance Ratio), The procedures include the identification of resolution, the improvement of R&R reduction, and the evaluation of precision effect.

A New Multivariate System Process Capability Index (다변량 시스템 공정능력지수(SCpsk))

  • 조남호;이용훈
    • Journal of the Korea Safety Management & Science
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    • v.5 no.3
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    • pp.145-156
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    • 2003
  • As we understand it, Process Capability indices are intended to provide single-number assessments of ability to meet specification limits on quality characteristics of interest. As a consequence of the varied ways in which PCIs are used, there have been two natural lines of research work: $\circled1$ studies on the properties of PCIs and their estimators in many different environments; $\circled2$ construction of new PCIs purporting to have better properties in certain circumstances. The most of existing process capability indices are concerned with the single variable. But, in many cases, a quality characteristic is composed with several factors. In that case, we want to know the integrated process capability of a quality characteristic not those of each factor. In this paper, we proposed a new multivariate system process capability index called $MSPCI:SC_{psk}$ which is the geometric mean of performance measure $C_{psk}$'S, and will be used as the criterion to assess multiple response process designs. Numerical illustration is done for $SC_{psk}$, $\overline{C_p}$(f), Cp, Cpk, Cpm, and Cpsk.

Vibration performance of composite steel-bar truss slab with steel girder

  • Liu, Jiepeng;Cao, Liang;Chen, Y. Frank
    • Steel and Composite Structures
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    • v.30 no.6
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    • pp.577-589
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    • 2019
  • In this study, on-site testing was carried out to investigate the vibration performance of a composite steel-bar truss slab with steel girder system. Ambient vibration was performed to capture the primary vibration parameters (natural frequencies, damping ratios, and mode shapes). The composite floor possesses low frequency (< 10 Hz) and damping (< 2%). Based on experimental, theoretical, and numerical analyses on natural frequencies and mode shapes, the boundary condition of SCSC (i.e., two opposite edges simply-supported and the other two edges clamped) is deemed more reasonable for the composite floor. Walking excitations by one person (single excitation), two persons (dual excitation), and three persons (triple excitation) were considered to evaluate the vibration serviceability of the composite floor. The measured acceleration results show a satisfactory vibration perceptibility. For design convenience and safety, a crest factor ${\beta}_{rp}$ describing the ratio of peak acceleration to root-mean-square acceleration induced from the walking excitations is proposed. The comparisons of the modal parameters determined by ambient vibration and walking tests reveal the interaction effect between the human excitation and the composite floor.

A Study on Increasing Reliability of Braking Force Inspection During Regular Inspection of Vehicles (자동차 정기검사에서 제동력 검사의 신뢰성 향상에 관한 연구)

  • Oh, Sang Yeob
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.40 no.8
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    • pp.725-729
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    • 2016
  • The regular inspection of vehicles that are in service in domestic country, i.e., vehicle safety and emission gas inspection have been forced by the korea transportation safety authority and a private servicing enterprise according to the vehicle administration law (1995). In the safety inspection process, which is developed by a compatible inspection system and method, every effort is made to increase the reliability of vehicle safety and the service quality, and to protecting national health. In this study, the reliability of the braking force inspection method in the current regular vehicle inspection was studied statistically by comparing the dynamic braking force inspection method with the static braking force inspection method. Further, the problems and characteristics of the current braking force inspection methods were analyzed. Form the results for the dynamic braking force inspection equipment (H), a mean correction factor (y=18.61+2.18x) was obtained for the axle braking force ratio according to vehicle entering velocity.

Do Various Respirator Models Fit the Workers in the Norwegian Smelting Industry?

  • Foereland, Solveig;Robertsen, Oeystein;Hegseth, Marit Noest
    • Safety and Health at Work
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    • v.10 no.3
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    • pp.370-376
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    • 2019
  • Background: Respirator fit testing is a method to assess if the respirator provides an adequate face seal for the worker. Methods: Workers from four Norwegian smelters were invited to participate in the study, and 701 respirator fit tests were performed on 127 workers. Fourteen respirator models were included: one FFABE1P3 and 11 FFP3 respirator models produced in one size and two silicone half masks with P3 filters available in three sizes. The workers performed a quantitative fit test according to Health and Safety Executive 282/28 with 5-6 different respirator models, and they rated the respirators based on comfort. Predictors of overall fit factors were explored. Results: The pass rate for all fit tests was 62%, 56% for women, and 63% for men. The silicone respirators had the highest percentage of passed tests (92-100%). The pass rate for the FFP3 models varied from 19-89%, whereas the FFABE1P3 respirator had a pass rate of 36%. Five workers did not pass with any respirators, and 14 passed with all the respirators tested. Only 63% passed the test with the respirator they normally used. The mean comfort score on the scale from 1 to 5 was 3.2. The respirator model was the strongest predictor of the overall fit factor. The other predictors (age, sex, and comfort score) did not improve the fit of the model. Conclusion: There were large differences in how well the different respirator models fitted the Norwegian smelter workers. The results can be useful when choosing which respirators to include in respirator fit testing programs in similar populations.

Critical Factor on Selection Indoor Air Quality improving alternatives for healthcare projects (병원의 실내 공기 질 솔루션 선택에 영향을 미치는 요인들)

  • Dang Nguyen-Hong Anh;Ahn, Yong-Han
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.63-64
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    • 2023
  • Indoor Air Quality is crucial in hospital projects to ensure the health and safety of patients, staff, and visitors. The research methodology comprises an comprehensive literature review, then a comprehensive questionnaire survey conducted among stakeholders involved in Vietnamese hospital projects. 15 variables were identified and categorized into four distinct groups, elucidating their influence on the adoption of advanced IAQ-enhancing technology. This study uses factor analysis, a mean score method and hypothesis test to analyze the factor result from the survey. two-step process, including an in-depth literature review and questionaire survey. The study's findings culminated in the ranking, examination, and categorization of these 15 variables, which were clustered into four essential categories: economic factors, design elements, governance strategies, and technical requirements. Additionally, the research explored viable solutions to improve indoor air quality in Vietnam's unique environmental context, examining the factors that impact the selection of such solutions. The study's outcomes yield practical recommendations for architects, engineers, and hospital administrators in enhancing IAQ within healthcare facilities. Furthermore, it presents a framework attuned to local environmental factors and building materials, contributing significantly to the existing body of knowledge on IAQ within hospital projects, particularly in the Vietnamese context.

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Fall Risk Assessment of the Elderly living in Nursing Home (노인요양시설 거주 노인의 낙상 위험요인 조사 연구)

  • Yang, Sun-Hee;Park, Young-Hae;Cho, Hae-Sook;Baek, Hee-Chong
    • Journal of Home Health Care Nursing
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    • v.12 no.2
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    • pp.1-15
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    • 2005
  • Purpose: This study was conducted to assess the fall risk factors. Method: The subjects were 87 persons who were older than 65 years living at 28 nursing home in Seoul and Gyunggi province. Subjects were interviewed using RAFS II for intrinsic factor and the environmental factor were assessed using a structured questionnaire from Oct. to Dec. in 2004. The data were analyzed by SPSS(ver. 12.0) programs, using descriptive statistics, $x^2$-test, and t-test. Result: The 37.9% of the subjects experienced the fall, and its average number is $1.94\pm1.75$. The Women's experience of the fall was higher than that of the men, but it was no significant difference with gender. There was no significant difference with the age and duration of living. The mean of the intrinsic risk factor was 13.38 in total score 39 points marks on the RAFS II scales. The intrinsic risk factor score of the fallen group 15.71 was significantly higher than the non-fallen group 12.10. The variables of recent fall experience(t=4.72, p=0.000) and urinary dysfunction(t=2.64, p=0.010) was significantly higher than the non-fallen group. The highest variable of the intrinsic factor was the age and the variables of drug intake, balance, chronic disease, recent fall experience, urinary dysfunction were followed in order. The mean of the environmental risk factor was 0.24 points. No significant differences were shown in environmental risk factor between the fallen and the non-fallen groups. To the fallen group, the place of entrance was the highest risky environmental factor. To see in area dimension, the floor surfaces was the highest risky environmental factor and equipment and illumination factor was the following risky elements in order. In the total score of environmental risk factors based on the ares, the fallen group was 0.26 and the non-fallen group was 0.24, but there were no significant differences between the groups. Conclusion: This results suggested that visual protection strategy, set up the safety device in the place of entrance and inner stairway, bathroom and nonskid mat in the nursing home would be contribute to the prevention of the fall for the elderly.

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Recognition Level of Imported Food and Its Correlation with Discrimination Ability (수입식품에 대한 인식도 및 분별력과의 상관성)

  • 한장일;김성애
    • Korean Journal of Community Nutrition
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    • v.4 no.1
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    • pp.95-102
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    • 1999
  • This study used questionnaires to investigate the safety awareness for imported foods by 365 male and female adults in Taejon. The results of the study were as follow : By factor analysis, the subjects' behaviors and awareness of the imported food was grouped into 3 factors such as 'health and quality factor', 'purchasing factor' and 'contamination factor'. 'Health and quality factor' and 'purchasing factor' were not recognized negatively by the subjects, moreover' contamination factor' was recognized very highly. The subjects' concern and worry about the imported food was also very high. The marital status, education level, nutriton knowledge adn recognition level of contamination by pesticides and heavy metals of foods partially affected the recognitio level of imported foods. The major selection criteria of imported food were distribution period(36.3%), price(28.8%) and purchasing experience(17.3%). The imported food mean discrimination score was 8.4±3.1 out of 13. The worst discriminatio score was red pepper. The subjects' experiences with imported foods selection affected the most instead of education level or nutrition knowledge. The higher discrimination score group more negatively recognized imported food and contamination recognition level was higher whereas the lowerdiscrimination score group more positively recognized the purchasing frequency and with to buy more easily. But both groups desired to reinforce contamination control. The better discrimination score of imported food pooring recognized sanitation concerns(p<0.05), quality(p<0.05), cooking convenience(p<0.01), desire for more variety(p<0.05), and the higher contamination recognition level(p<0.05) and desire to reinforce contamination control(p<0.01).

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A Study on Residential Modification Demand by Elderly Lived in Detached Housing - Focusing on Application of Ubiquitous Home Services - (단독주택 거주 노인의 주택개조 요구에 관한 연구 - 유비쿼터스 홈 서비스 적용을 중심으로 -)

  • Ha, Hae-Hwa;Kwon, Oh-Jung
    • Korean Institute of Interior Design Journal
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    • v.21 no.2
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    • pp.141-151
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    • 2012
  • Korea is a fast growing aging society. Growing older population causes various social issues and problems in many aspects. Housing issue is one of them and residential modifications for improving safety and independence for older residents are very important factor for Aging in Place. Under those social circumstances, the purpose of this study was to analyze the residential modification demand by the elderly on the application of ubiquitous home services. Respondents were the residents those who were over 55 years old, were living in a singe detached house and were able to use a computer. The major findings of this study were as follows: the results on current situations and demands for residential modifications showed that respondents already made mean of 4.9 home modification items and wanted to make mean of 12.4 items out of 21 residential modification items. The results on demands for the ubiquitous home services was relatively high(mean 3.82). This study can be an important information which is able to improve the quality of life by providing effective residential modifications for older population to help them ultimately safe, convenient, and independent living.

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