• Industrial Engineering and Management Systems
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• v.3 no.2
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• pp.134-139
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• 2004

During the last three decades, a few attentions have been paid for investigating the cost distribution for the optimal maintenance problems. In this article, we derive the moment of the discounted cost distribution over an infinite time horizon for the basic age replacement problem. With first two moments of the discounted cost distribution, we approximate the underlying distribution function by three theoretical distributions. Through a Monte Carlo simulation, we conclude that the log-normal distribution is the best fitted one to approximate the discounted cost distribution.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.12 no.2
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• pp.81-95
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• 2008

In this paper, the negative Polya-Eggenberger distribution has been introduced by compounding negative binomial distribution with beta distribution of I-kind which generates a number of univariate contagious or compound (or mixture of) distributions as its particular cases. The distribution is unimode, over dispersed and all of its positive and negative integer moments exist. The difference equation of the proposed model shows that it is a member of the Ord's family of distribution. Some of its interesting properties have been explored besides different methods of estimation been discussed. Finally, the parameters of the proposed model have been estimated by using a computer programme in R-software. Application of the proposed model to some data, available in the literature, has been given and its goodness of fit demonstrated.

• Journal of Distribution Science
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• v.12 no.10
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• pp.37-45
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• 2014

Purpose - This study aims to analyze the relationship between trends in innovative EU industries and market distribution in smaller emerging markets under an open economy. Research design, data, and methodology - Although innovation was well-distributed, due to socio-economic factors following European integration, CEE had not achieved sustainable economic growth. However, this paper analyzes the differences among changes in CEE innovation for smaller emerging markets dominated since 2000. Market distribution has facilitated new markets for innovative industries, according to EU surveys and economic indicators. Results - The dominance of the local industrial market distribution has deterred innovation investment the survey shows that innovation investment has been shrinking, despite the EU's open innovation policy for CEE employment and R&D. For the CEE case, there were expectation gaps and uncertainty about whether to use the new distribution dominance or TNCs' innovation in smaller emerging countries without local industrial innovation. Conclusions - Innovation generates market growth and distribution power however, small growth requires stimulation, and creativity and innovative edge need further focus in local public and corporate strategy.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.105-108
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• 2013

Drivers' sitting strategies are considered in car seat design. Existing research has identified representative sitting strategies by visual inspection of seating pressure measurements collected from a small sample size of drivers. The present study recruited 20 female and 20 male participants, measured seating pressure, and classified sitting strategies by cluster analysis. The participants' sitting postures were classified based on seating pressure distribution into mid-back and scapular, mid-back and lumbar, and lumbar sitting strategies for the upper body and hip concentrated, hip and mid-thigh concentrated, and hip and mid-thigh distributed sitting strategies for the lower body. The effects of gender and occupant package layout (OPL) on sitting strategy were nout found significant. The identified sitting strategies would be of use for the design and evaluation of an OPL and a seat.

• Journal of Powder Materials
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• v.27 no.1
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• pp.44-51
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• 2020

Powder characteristics, such as density, size, shape, thermal properties, and surface area, are of significant importance in the powder bed fusion (PBF) process. The powder required is exclusive for an efficient PBF process. In this study, the particle size distribution suitable for the powder bed fusion process was derived by modeling the PBF product using simulation software (GeoDict). The modeling was carried out by layering sintered powder with a large particle size distribution, with 50 ㎛ being the largest particle size. The results of the simulation showed that the porosity decreased when the mean particle size of the powder was reduced or the standard deviation increased. The particle size distribution of prepared titanium powder by the atomization process was also studied. This study is expected to offer direction for studies related to powder production for additive manufacturing.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.3 no.2
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• pp.194-203
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• 1993

Quality Control programs for industrial hygiene laboratory have successfully been operated since the 1st round was initiated in April 1992. Three rounds have been completed. Overall analytical performance of participants was improved through a subsquent round. The first round had a large variation among analytical results of all participants, 26.34%~504.22% of coefficient of variation. But the variation of analytical performance in the 2nd and 3rd rounds decreased to 40.42%~52.55% and 10.74%~20.98%, respectively. The difference of analytical performance among participants was decreased by operation of subsquent round. By distribution of Running Performance Index (RPI), over 50% of participants belongs to Category 3 in the first round. The average percentage of participants assigned to Category 3 in the 2nd and 3rd round was decreased to 37.2%. A definite analytical performance improvement of participants seems to be obtained. "A" and "B" group have more participants assigned to Category 3 than those of "C" group through the distribution of RPI by group divided to similar participant. By the distribution of RPI all participants, the percent of participant being over 200 RPI in the 1st round was 43%~52%, but decreased to 9%~29% and 9%~27%, in the 2nd and 3rd round, respectively. These results mentioned above indicate that the analytical performance of all participants have been improved by subsquent Quality Control Program although newcomers joined and a few participants droped out. But, there are some participants with poor analytical performance. Industrial Health Research Institute (IHRI) will offer service such as education, communication and visitation to them, and improve quality of their analytical performance in the future.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.256-266
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• 2020

Objectives: The concentrations and distribution characteristics of volatile organic compounds (VOCs) in an industrial complex and surrouding affected residential areas were investigated in an effort to support the efficient management of VOCs. Methods: The atmospheric concentrations of VOCs were analyzed at sites around the Sihwa-Banwol complex located in the cities of Siheung and Ansan and in the surrounding affected residential areas. The appearance of VOCs and the characteristics of their temporal and spatial distribution were evaluated. Results: The total VOC concentrations in the industrial complex were detected at 1.9-2.3 times higher than in the affected areas, but the daily VOCs distributions showed similar patterns in both sites. In particular, it was confirmed that the composition ratio of the VOCs and concentration fluctuations over time in the affected areas are similar to those in the adjacent industrial complex. VOC levels in the affected areas were higher than in residential areas in cities without an industrial complex. Conclusions: VOCs in residential areas near an industrial complex were highly distributed due to the influence of continuous pollutant emissions from the industrial complex. Therefore, the management of VOCs in the atmosphere of the affected area is important for identifying and managing the sources of VOCs detected in high concentrations in the industrial complex.

• Journal of Preventive Medicine and Public Health
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• v.21 no.2 s.24
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• pp.374-379
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• 1988

In order to prepare the fundamental data for preventing the hazardous effects at toluene exposure in many kinds of industry, the authors determined the level of urinary hippuric acid on 592 toluene exposed women(exposed group) and 102 unexposed women(control group) in Pusan area, from April. 1 to October 31, 1986. Hippuric acid was measured by high performance liquid chromatography. The results were summarized as follows; 1. The mean value of urinary hippuric acid concentration of the control group was $0.44{\pm}0.21g/l$(0.11-0.89g/l). The distribution of urinary hippuric acid concentration of the control group was not fit to the normal distribution. 2. The mean value of urinary hippuric acid concentration of the exposed group was $1.56{\pm}0.95g/l$(0.44-4.57g/l). The distribution of urinary hippuric acid concentration of control group was not fit to the normal distribution. 3. The urinary hippuric acid concentration by age group was not statistically significant in the control group, but in the exposed group the urinary hippuric acid concentration was highest in women between 20-29 years old($1.71{\pm}0.95g/l$) and was statistically significant(p<0.01). 4. The urinary hippuric acid concentration by duration of working hours was not statistically significant (p>0.1).

• Industrial Engineering and Management Systems
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• v.10 no.2
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• pp.154-160
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• 2011

In this paper, a reliability sampling plan under progressively type-1 interval censoring is proposed when the lifetime of products follows the Pareto distribution of second kind. We use the maximum likelihood estimator for the median life and its asymptotic distribution. The cost model is proposed and the design parameters are determined such that the given producer's and the consumer's risks are satisfied. Tables are given and the results are explained with examples.

• Journal of the Korea Safety Management & Science
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• v.18 no.2
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• pp.65-71
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• 2016

This study was aimed to demonstrate how the analysis of the impact on confidence in the safety-conscious organizations target the clothing distribution center employees and organizational commitment. Safety awareness of employees of the clothing distribution center safety rules, safety education, road safety interests, divided into risk handling and trusted organization with the emotional trust and cognitive trust, organizational commitment was divided into affective, cognitive and normative commitment. Data collection was surveyed 185 people clothing distribution center workers, tested the hypothesis through regression analysis. The results are safety conscious exerts a positive effect on organizational trust, organizational trust was found to have a positive impact on organizational commitment.