• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.431-437
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• 2010

It's strongly needed to minimize the logistics response time for supporting military operations in wartime. In this paper, we suggest the ILP formulation for minimizing logistics response time in wartime. Main structure of this formulation is based on the traveling purchaser problem(TPP) which is a generalized form of the well-known traveling salesman problem(TSP). In the case of general TPP, objective function is to minimize the sum of traveling cost and purchase cost. But, in this study, objective function is to minimize traveling cost only. That's why it's more important to minimize traveling cost(time or distance) than purchase cost in wartime. We find out optimal solution of this problem by using ILOG OPL STUDIO(CPLEX v.11.1) and do the sensitive analysis about computing time according to number of operated vehicles.

• Korean Journal of Environmental Biology
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• v.24 no.2 s.62
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• pp.126-137
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• 2006

Effect of night-lights on zooplankton attraction has been studied in Tongyeong marine ranch area during the period from 12 July to 30 August, 2004. Each sampling has been carried out to collect zooplankton from both control area in natural waters experiment area of night-lights waters at night. A total of 43 taxa of zooplankton occurred during the study. Copepods showed the prosperity in species number with 15 species. Acartia erythraed and Copepodite occurred abundantly in night-lights waters. Zooplankton abundance appeared to increase in night-lights mainly due to the gathering of copepods and larvae through the study period. Average $3\sim166$ times of zooplankton abundance was recorded in night-lights when compared with that in control area of natural waters due to the gathering of copepods and larvae. Cluster analysis, based on monthly abundance data of the 13 most frequent species, showed that the species were seperated into two different groups: the photo-positive group and the photo-negative group.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.10
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• pp.685-690
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• 2014

The treatment of combined sewer overflow (CSO) is one of potential concerns in domestic wastewater treatment in Korea due to the pre-announce of CSO regulations. This work investigated the effects of disinfectant (NaOCl) concentration (0.11 to 4.0 mg $Cl_2/L$), pH (6.5 to 8.0), temperature (15 to $25^{\circ}C$), ammonia (10 to 41 mg N/L), and suspended solids (91 to 271 mg SS/L) on the chlorine disinfection of CSO. The effect of NaOCl concentration on the pseudo-$1^{st}$ order reaction rate for total coliform inactivation was described well with a saturation-type model with the half-velocity constant of 1.212 mg/L. The total coliform inactivation reaction rate decreased with SS and pH, and increased with temperature. Ammonia in the examined range did not affect the disinfection kinetics. A chlorine contact tank with the injection chlorine level of 1 mg $Cl_2/L$ and the hydraulic retention time of 1.25 min is estimated to reduce total coliform from $1{\times}10^5MPN/mL$ to 1,000 MPN/mL at 271 mg SS/L, $15^{\circ}C$, and pH 8.0. Chlorine would be a proper option for the disinfection of CSO.

• Journal of the Korea Organic Resources Recycling Association
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• v.1 no.1
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• pp.69-84
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• 1993

In order to determine the optimum operational paramsters in cow manure composting, 4 laboratory scale composters were established. The cow manure was mixed with certain amount of saw dust to adjust the initial C/N ratio to 24, initial pH to 6.9 and composting was performed with varying operational conditions. It was found that the optimum aeration rate was 1000 ml/min kg. VS, the optimum moisture content 50% and no significant difference was found with different initial pH condition. Microorganisms were counted under the optimum conditions determined in this study. At the end of the experimental period, the number of bacteria, actinomycetes and fungi was $1.5{\times}10^9$ cells, $1.1{\times}10^8$ cells and $3.0{\times}10^8$ cells/g dry compost, respectively. At day 0, the number of coliforms, fecal coliforms and fecal streptococci was $3.1{\times}10^3$ cells, $7.5{\times}10^2$ cells and $5.6{\times}103$ cells/g dry composting material, respectively. Their population was decreased with time lapse, However, their survival time was longer than those reported by other researchers. Microorganisms were identified at the end of the experiment. Genus Bacillus was the most dominant comprising 89.3% of the total population. Among the Genus Bacillus, B. circulans compoex was the most abundant, followed by B. Stearothermophilus, B. Sphericus, B. licheniformis and B, brevis.