• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.29-40
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• 1999

The distribution center location and routing problem involves interdependent decisions among facility, transportation, and inventory decisions. The design of distribution system affects the customers' purchase decision by sets the level of customer service to be offered. Thus the lower product availability may cause a loss of demand as falls off the customers' purchase intention, and this is related to the firm's profit reduction. This study considers the product availability of the distribution centers as the measure of the demand level change of the demand points, and represents relation between customer service and demand level with linear demand function. And this study represents the distribution center location and routing to demand point in order to maximize the total profit that considers the products' sales revenue by customer service, the production cost and the distribution system related costs.

• Journal of Applied Reliability
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• v.15 no.3
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• pp.192-196
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• 2015

It is important to obtain the information of population center for establishing the balanced development policy of a nation. In this note, the population center of Korea is obtained using 2010 Census data and compared with the past population centers. The weighted average method is used for calculating the population center. The results of this note will be able to contribute in the regional population distribution policies.

• Journal of the Chungcheong Mathematical Society
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• v.27 no.3
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• pp.405-411
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• 2014

Queueing systems with retrials are widely used to model many problems in call centers, telecommunication networks, and in daily life. We present a very accurate but simple approximate formula for the distribution of the number of retrying customers in the M/G/1 retrial queue.

• Korean Journal of Social Welfare
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• v.29
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• pp.105-131
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• 1996

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.59-72
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• 1994

This paper deals with ordering policies of consumable goods which have large demand rates in a multi-level distribution system. The system we are concerned consists of one Central Distribution Center(CDC) and N non-identical Regional Distribution Centers(RDCs) which have different demand rates, minimum fillrates, leadtimes, etc. The customer demand on the RDC is stationary poisson and the RDCs demand on the CDC is superposition of Q-stage Erlang distributions. We approximate the RDCs and CDC demand distribution to nomal in order to enhance the efficiency of algorithm. The relevant costs include a fixed ordering cost and inventory holding cost, and backorder cost. The objective is to find a continuous-review ordering policy that minimizes the expected average costs under constraints of minimum fill rates of RDCs and maximum allowable mean delay of CDC. We developed an algorithm for determining the optimal ordering policies of the CDC and the RDCs. We verified and compared the performance of the algorithm through the simulation using the algorithm result as the input parameters.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.1070-1078
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• 2016

This study investigated the nutrition education realities and nutrition status of children in community child centers, by analyzing the status of nutrition education, nutrition quotient (NQ), and the level of maintaining dietary guidelines. The subjects were 173 children from grades 1 to 6, enrolled in community child centers, Jinju, Kyungnam. The NQ was examined by a questionnaire, which was a checklist of 19 food behavior items. The distribution of scores (out of 100) in the nutrition quotient were as follows: total score of NQ was 59.4, balance 56.6, diversity 60.6, moderation 65.6, regularity 60.9, and practice 56.7. Nutrition quotient was higher in the higher graders due to significant differences in the area of variety. The level of maintaining dietary guidelines was higher in girls, especially in the area 'eat politely with family', and higher amongst the upper graders in the area 'have safe snack wisely'. To improve the eating habits and nutritional status of the children in community child centers, their nutritional state should be checked with regular and systematic education, and their nutritional management should be pursued continuously. Since the assessment of the eating behaviors and the nutritional state of children is important at home as well as in schools and community child centers, nutritional education should be further extended to the parents and their care givers. This study can be implemented as basic material for the nutritional education of children, to minimize the dangers of malnutrition and to help build up the right eating habits amongst children in community child centers.

• Journal of Environmental Health Sciences
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• v.33 no.1 s.94
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• pp.49-56
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• 2007

The purpose of this study was to survey the distribution patterns of volatile organic compounds(VOCs) and formaldehyde in the various indoor environments using cluster analysis. We investigated VOCs and formaldehyde in subway stations, underground shopping areas, medical centers, maternity recuperation centers, public childcare centers, large stores, funeral houses, and indoor parking lots from June,2005 to May,2006. Concentration of TVOCs in maternity recuperations was 2,605.7 ${\mu}g/m^3$ that was higher than the guideline and other facilities. TVOCs in public childcare centers was 1,951.6 ${\mu}g/m^3$ also it exceeded the guideline. Moreover, concentration of TVOCs in every facility exceeded the guideline of Department of Environment, Korea. In case of formaldehyde, mean concentration, 336.5 ${\mu}g/m^3$, in only public childcare centers exceeded the 120 ${\mu}g/m^3$ of the guideline. Finally, by applying cluster analysis, three pattterns of the indoor air pollutions were distinguished. In the results of analysis, concentrations of TVOCs and formaldehyde of cluster 3 were higher than cluster 1 and 2 that were 2,561.4 ${\mu}g/m^3$ and 184.9 ${\mu}g/m^3$, respectively.

• Parasites, Hosts and Diseases
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• v.57 no.5
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• pp.531-536
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• 2019

Cryptosporidium parvum and Giardia duodenalis are the main diarrhea-causing parasitic pathogens; however, their prevalence in Korea is unknown. Here, we conducted a survey to determine the prevalence and genotype distribution of these 2 pathogens causing acute diarrhea in 8,571 patients hospitalized in 17 Regional Institute of Health Environment sites in Korea, during 2013-2016. C. parvum and G. duodenalis were detected and genotyped by nested PCR, and the isolate were molecularly characterized by sequencing the glycoprotein 60 (Gp60) and ${\beta}-giardin$ genes, respectively. The overall prevalence of C. parvum and G. duodenalis was 0.37% (n=32) and 0.55% (n=47), respectively, and both pathogens were more prevalent in children under 9 years old. Molecular epidemiological analysis showed that the C. parvum isolates belonged to the IIa family and were subtyped as IIaA13G2R1, IIaA14G2R1, IIaA15G2R1, and IIaA18G3R1. Analysis of the ${\beta}-giardin$ gene fragment from G. duodenalis showed that all positive strains belong to assemblage A. This is the first report on the molecular epidemiology and subtyping of C. parvum and G. duodenalis in such a large number of diarrheal patients in Korea. These results highlight the need for continuous monitoring of these zoonotic pathogens and provide a basis for implementing control and prevention strategies. Further, the results might be useful for epidemiological investigation of the source of outbreak.

• Structural Engineering and Mechanics
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• v.63 no.3
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• pp.281-292
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• 2017

Architecture constraints in buildings may typically cause irregularities in the distribution of stiffness and mass and consequently causes non-compliance of centers of mass, stiffness and strength. Such buildings are known as asymmetric buildings the distribution of strength and stiffness is one of whose main challenges. This distribution is more complicated for concrete buildings with RC shear walls in which stiffness and strength are interdependent parameters. The flexibility under the foundation is another subject that can affect this distribution due to the variation of dynamic properties of the structure and its constituting elements. In this paper, it is attempted to achieve an appropriate distribution pattern by expressing the effects of foundation flexibility on the seismic demand of concrete shear walls and also evaluate the effects of this issue on strength and stiffness distribution among lateral force resistant elements. In order to understand the importance of flexibility in strength and stiffness distribution for an asymmetric building in different conditions of under-foundation flexibility, the assigned value to each of the walls is numerically calculated and eventually a procedure for strength and stiffness distribution dependencies on flexibility is provided.

• Journal of Environmental Health Sciences
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• v.46 no.4
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• pp.359-367
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• 2020

Objectives: Exposure to mold is strongly associated with adverse health effects (development or exacerbation of allergic diseases). We reviewed the health effects of mold exposure and explored to determine the annual distribution of indoor mold in facilities with susceptible populations. Methods: The health effects of mold exposure were mainly summarized by reviewing related papers and WHO research reports. We selected 10 facilities, including daycare centers, postpartum care centers, medical institutions, and elderly care facilities within the Seoul Metropolitan. Mold sampling was performed once every week or once every quarter from February 2016 to 2017. In addition, fungal species analyses was performed, and distribution status by month and facility was analyzed in the same manner as concentration. Results: Adverse health effects attributed to fungal exposure are largely divided into allergic symptoms, toxic effects, and infectious effects. Monthly mean concentrations of mold indoors and outdoors was 368.8 CFU/㎥ (geometric mean 213.4 CFU/㎥) and 496.0 CFU/㎥ (327.9 CFU/㎥), respectively. The indoor concentration has begun to increase in February, peaked in July, declined in August, increased again until October, and then decreased in November. About 36 genera of indoor fungal species were found in each facility. Cladosporium sp., Penicillium sp., Fusarium sp., Aspergillus sp., Alternaria sp., and Arthrinium sp. were observed as the dominant species. Conclusions: Our findings showed that the overall level of indoor mold was below the 500 CFU/㎥ level recommended by the Ministry of Environment. The development of DNA-based assessment and expanding facilities to be monitored for mold would be necessary for preventive aspects.