• Communications for Statistical Applications and Methods
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• v.22 no.2
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• pp.137-146
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• 2015

Singh (2013) considered the dual problem to the calibration of design weights to obtain a new generalized linear regression estimator (GREG) for the finite population total. In this work, we have made an attempt to suggest a way to use the dual calibration of the design weights in case of multi-auxiliary variables; in other words, we have made an attempt to give an answer to the concern in Remark 2 of Singh (2013) work. The same idea is also used to generalize the GREG estimator proposed by Deville and S$\ddot{a}$rndal (1992). It is not an easy task to find the optimum values of the parameters appear in our approach; therefore, few suggestions are mentioned to select values for such parameters based on a random sample. Based on real data set and under simple random sampling without replacement design, our approach is compared with other approaches mentioned in this paper and for different sample sizes. Simulation results show that all estimators have negligible relative bias, and the multivariate case of Singh (2013) estimator is more efficient than other estimators.

• Environmental Engineering Research
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• v.15 no.2
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• pp.85-91
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• 2010

Romania aims to adopt and implement the European Union's legislation, also including that for the field of water management. Like other countries, groundwater in Romania is locally polluted from point sources, such as leaking landfills, as well as from diffuse pollution sources, include fertilizers, pesticides and leakages from sewers, in urbanized areas. Diffuse pollution can also occur indirectly, by over-exploitation of groundwater wells, resulting in salt water intrusion, as well as from mining and exploitation of mineral aggregates. Romania has quite an intensive monitoring scheme to measure groundwater quality in phreatic and confined aquifers. The purpose of the work resumed in this paper was to derive natural background levels (NBL) for groundwater in order to distinguish the natural elevated concentrations of some substances (natural phenomena) from point and diffuse pollution (anthropogenic phenomena). Based on these NBLs, threshold values (TV) for groundwater will be set according to the requirements of the European Water Framework Directive and the related Groundwater Directive. This paper describes the results of a study for the derivation of NBL and TV in a pilot Groundwater Body. Also, the process and draft results for extrapolating this work for all Romanian groundwater bodies is explained, as well as points for future consideration with respect to monitoring and management.

• Safety and Health at Work
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• v.8 no.2
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• pp.206-211
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• 2017

Background: Self-reported low back pain (LBP) has been evaluated in relation to material handling lifting tasks, but little research has focused on relating quantifiable stressors to LBP at the individual level. The National Institute for Occupational Safety and Health (NIOSH) Composite Lifting Index (CLI) has been used to quantify stressors for lifting tasks. A chemical exposure can be readily used as an exposure metric or stressor for chemical risk assessment (RA). Defining and quantifying lifting nonchemical stressors and related adverse responses is more difficult. Stressor-response models appropriate for CLI and LBP associations do not easily fit in common chemical RA modeling techniques (e.g., Benchmark Dose methods), so different approaches were tried. Methods: This work used prospective data from 138 manufacturing workers to consider the linkage of the occupational stressor of material lifting to LBP. The final model used a Bayesian random threshold approach to estimate the probability of an increase in LBP as a threshold step function. Results: Using maximal and mean CLI values, a significant increase in the probability of LBP for values above 1.5 was found. Conclusion: A risk of LBP associated with CLI values > 1.5 existed in this worker population. The relevance for other populations requires further study.

• Nuclear Engineering and Technology
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• v.13 no.1
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• pp.12-21
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• 1981

An extension work of the previous paper on the rewetting velocity model is presented. Application of the rewetting velocity model presented elsewhere requires a priori values of ø. In the absence of ø values, film boiling heat transfer coefficient ( $h_{df}$ ) and fog-film length (ι) data are needed. To provide these informations, a modified Bromley's correlation is first derived and used to obtain $h_{df}$ values at higher pressure conditions. In addition, the analysis of the precooling parameters, such as ø and ι is further extended using much more expansive PWR FLECHT data. Thus, the applicable range of the rewetting velocity model is further expanded in this work.

• Journal of Society of Preventive Korean Medicine
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• v.24 no.1
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• pp.49-56
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• 2020

Objective : The purpose of this study is to determine the Work value of Korean medicine college students and check how the Work value of college students affects major commitment and major satisfaction. Method : The data for this study were collected through a self-administered survey to 207 subject from students enrolled in the University in B city. Frequency analysis, repeated measures ANOVA, multiple regression analysis were used for the statistical analysis. Results : As a result of analyzing the occupational value of students enrolled in the College of Korean Medicine, the pursuit of professionality and interest was the highest, the pursuit of achievement was the next highest, and the pursuit of diversity and change was the lowest. As a result of the multiple regression analysis, pursuit of achievement and professionality had a positive(+) effect, and pursuit of ease had a negative(-) effect on the major commitment. Also, the pursuit of professionality and interest had a positive(+) effect, and pursuit of ease had negative(-) effect on major satisfaction. Conclusion : In order to increase students' major commitment and satisfaction, it is necessary to make efforts to compose the programs and educational contents that can satisfy these values. In addition, the efforts of universities and professors are needed to help students establish the correct their work value.

• Journal of the Korean Vacuum Society
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• v.12 no.1
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• pp.16-19
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• 2003

Ni thin films on the p-InP (In) substrates were grown at room temperature by using the ion beam-assisted deposition. In order to determine the work function of the Ni thin films, the $\gamma$values were measured as functions of the acceleration voltages by using Ne, Ar, $N_2$. and Xe ion sources. The dependences of the values on various gases and on the acceleration voltages of the focused ion beam were obtained to determine the work function of the Ni thin films. The value of the work function of the Ni thin films grown on the p-InP (100) substrate was 5.8 eV ~ 5.85 eV. These results provide important information on the electronic properties of Ni thin films grown on p-InP (100) substrates at room temperature.

• Journal of Environmental Health Sciences
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• v.45 no.2
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• pp.173-185
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• 2019

Objectives: The objectives of this study are to evaluate the accuracy and precision of exposure model ECETOC TRA v.3.1 by comparing model predictions with repeated exposure measurements in Korean workplaces and to investigate the applicability of ECETOC TRA to Korean workplace exposure assessment in K-REACH. Methods: Measured values and work conditions for 14 kinds of chemicals collected from exposure field surveys conducted at 10 companies in Korea were utilized for this study. All possible process categories (PROCs) considered to be relevant to each work process classification were selected and applied to ECETOC TRA as major determining parameters. In order to quantify the accuracy of the model, the lack of agreement (bias, relative bias, precision) was calculated and the risk ratios for each exposure situation between estimated and measured were also compared. Results: The estimated values varied between five and 25 times according to the PROCs for all exposure situations (ESs) based on tasks/chemicals. The results showed that most of the estimated values were below the measured values, and just 13 of 53 tasks were above the measured values. The overall bias and precision were $-2.91{\pm}1.62$ with ECETOC TRA, and we found that ECETOC TRA showed a low level of conservatism when applied to Korean workplaces, similar to previous studies. Conclusions: This study demonstrates that the existed PROC codes have limitations in fully covering various ESs in Korea. In order to improve the applicability of ECETOC TRA in K-REACH, the addition of new PROCs for Korean industries are necessary.

• Journal of Family Resource Management and Policy Review
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• v.24 no.2
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• pp.1-21
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• 2020

The purpose of this research was, first, to classify work-life satisfaction among married wage workers aged 20-59 years into several distinct types based on two dimensions of work and life, using data from the 20th(2017) wave of the Korean Labor & Income Panel Study. Second, the study aimed to assess the differences in socio-demographic characteristics (sex, age, educational level, average monthly income), and workplace-related variables (weekly working hours, full-time employment, job stability, business type, family-friendly leave policies) by work-life satisfaction type. Accordingly, four types of work-life satisfaction were identified: work-life satisfaction, work-life dissatisfaction, work satisfaction, and life satisfaction. There was a significant difference in the type of work-life satisfaction among married waged workers based on sex, age, educational level, and average monthly income. Additionally, there was a significant difference in the type of work-life satisfaction for all workplace-related variables, namely, weekly working hours, full-time employment, job stability, business type, and family-friendly leave policies. In particular, proportionally higher values of work-life satisfaction were evident among the workers in companies with family-friendly leave policies such as paid leave, menstrual leave, maternity leave, childcare leave, and family events leave, whereas there was a high rate of work-life dissatisfaction among the workers in companies without family-friendly leave policies.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.2
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• pp.161-167
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• 1983

In this study the phenomenon of cutting stress which arises on cutting tools and work pieces in cutting process is investigated by rake angle of cutting tools and feed for this measurement, P$_{s}$-1 (high modulus, photolastic Inc.) was used as a cutting tool, P$_{s}$-3 (medium modulus, photolastic Inc.) was used as work piece and reduction apparatus was attached to the head stock, and orthogonal cutting was adapted as a cutting method and transparent glass was used to block the strain in the orientation of thickness. The followings are the results of this study. (1) Photoelastic experimental equipments have made it possible to make dynamic measurement and analyze stress distribution in cutting tool and work piece surface which has hitherto been conducted only in static measurement and analyzing method. (2) The maximum stress arising at tools and work pieces in cutting process is on the tool edge tip, and the maximum stress arising on the tip of cutting tools is equal to that on the contacting area of work pieces in values. (3) The distributions of maximum shear stress on certain parts of the cutting tools and work pieces are as follows; for cutting tools, .alpha.=12.deg., .alpha.=0.deg., .alpha.=-12.deg. in order, and for work pieces, .alpha.=-12.deg., .alpha.=0.deg., .alpha.=12.deg. in opposite order.der.

• Journal of Korean Institute of Industrial Engineers
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• v.16 no.1
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• pp.67-81
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• 1990

Effectiveness of physical exercise in reducing work-related musculoskeletal stress was investigated. This was compared to the stress alleviation accomplished by using ergonomically designed work station. Tasks chosen for the study were data entry and file maintenance on the video display terminal (VDT). Three different measures, namely root-mean-square (RMS) values of electromyogram (EMG), subjective rating and task performance were used for the evaluation. Electromyograms were recorded from the neck, the left and right trapezius muscles in the shoulder region, and L2/L3 region of the back. Subjects rated discomfort levels for the same parts of their body. Task performance was measured by recording typing speed and errors. Each of the five subjects was tested for two days (8 hours/day) in two different work stations. These were the ergonomically designed adjustable work station and the fixed work station of traditional design with no adjustable features. Assigned physical exercises were performed for four minutes, every two hours during the breaks, by the subjects while working in the fixed work station. It was concluded that the physical exercise could be helpful in reducing musculoskeletal stress as effectively as the ergonomic design of the VDT work station.