• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.430-430
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• 2021

최근 상수관망 시스템에 ICT 기술을 접목하여 수돗물 공급에 대한 신뢰도를 향상시키기 위한 노력이 증가하고 있다. 특히, 관 내 수질이 일정 기준 미달인 경우 실시간 수질 감지를 통해 이상수질을 자동으로 배출하는 자동드레인 시스템이 수질사고 예방 및 대응 방안으로 주목받고 있다. 현재 자동드레인 시설은 관로 말단에서의 잔류염소 유지를 위한 목적으로 주로 사용되고 있고, 도시지역 내 수질사고에 대비한 설치, 운영사례는 부족한 상황이다. 따라서 본 연구에서는 인천시 Z지역 내 자동드레인의 운영에 따른 상수관망의 수리적 특성을 분석하였다. EPANET 프로그램을 사용하여 배수지에서 수질오염이 발생한 조건을 가정하였고 배수지의 공급량에 따라 2가지 모의조건으로 나누었다. 첫 번째 모의조건은 배수지의 공급량을 일정하게 유지시킨 상태로 자동드레인의 배출량을 증가시키는 것이었고, 두 번째 모의조건은 급수구역의 공급량을 일정하게 유지시킨 상태로 자동드레인의 배출량을 증가시키는 것이었다. 각 조건별로 자동드레인의 배출량을 증가(배수지의 10%~90%)시키면서 관망 전체의 수리적 변화(압력, 에너지)를 비교·분석하였다. 첫 번째 모의조건에서는 자동드레인 배출량이 증가할수록 모든 절점에서 압력이 증가하였고 수두가 낮은 절점일수록 압력 변화가 커지는 것으로 나타났다. 또한, 인천 Z지역에서는 60% 이상 배출 시 에너지가 거의 증가하지 않고 일정한 값으로 수렴하는 경향을 보였다. 두 번째 모의조건에서는 자동드레인의 배출량이 증가할수록 압력이 모든 절점에서 동일하게 감소하였으며 에너지는 일정하게 증가하였다. 본 연구 결과는 상수관망 내 수질관리 시스템 구축 시 기초자료로 활용될 수 있으며 스마트 물 관리에 도움이 될 것으로 기대된다.

• Journal of Environmental Science International
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• v.32 no.12
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• pp.973-978
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• 2023

This study determined the mechanisms of selection of companion plants that will increase natural enemies and compared and analyzed the effect of suppression of pest density and changes in pest and natural enemy density and spatial distribution, aiming to select suitable companion plants to control major pests that are problematic in organic tomato facility cultivation. As a result of the companion plant selection, 13.5 days were identified in the area with daily flowers among five species of flowering plants. In the experiment to determine the timing of natural enemies, the best results were found in the treatment group introduced two weeks before the pest occurred. As a result of the actual package test, farmers could see that the density of greenhouse pollen decreased significantly (100-500% for adults and 11-67% for larvae compared to no treatment) in the treatment with companion plants. Based on the results of this study, we expect that ecological pest management using companion plants that attract natural enemies will help to increase biodiversity through vegetation management, secure the safe production of organic products and improve the sustainability of agriculture.

• Journal of the Korean Society of Safety
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• v.39 no.1
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• pp.9-15
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• 2024

Hydrogen-based electricity and transportation systems are widely recognized as sustainable power sources. However, the low ignition energy of hydrogen, only 1/10th that of conventional fossil fuels, poses a safety concern involving the risk of ignition due to electrostatic discharge from facility workers. Therefore, anti-static systems are imperative for hydrogen-based electricity facilities. To address this, we propose a reliable conductive rubber mat (CRM) to ensure the safety of these facilities. Unlike conventional anti-static floors that utilize conductive paint (CP), the CRM features a uniform distribution of conductive components in chemically and mechanically stable rubber. As a result, the CRM is unyielding to polar solvents (such as ethanol and hydrosulfuric acid) and non-polar solvents (like mineral oil) without increasing its resistance. Moreover, the CRM can withstand mechanical stress. Consequently, the human-body voltage of workers on the CRM would be sufficiently low enough to protect them from hydrogen explosions, thereby enhancing overall safety.

• Journal of Intelligence and Information Systems
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• v.16 no.4
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• pp.131-145
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• 2010

The framework for making a coordinated decision for large-scale facilities has become an important issue in supply chain(SC) management research. The competitive business environment requires companies to continuously search for the ways to achieve high efficiency and lower operational costs. In the areas of production/distribution planning, many researchers and practitioners have developedand evaluated the deterministic models to coordinate important and interrelated logistic decisions such as capacity management, inventory allocation, and vehicle routing. They initially have investigated the various process of SC separately and later become more interested in such problems encompassing the whole SC system. The accurate quotation of ATP(Available-To-Promise) plays a very important role in enhancing customer satisfaction and fill rate maximization. The complexity for intelligent manufacturing system, which includes all the linkages among procurement, production, and distribution, makes the accurate quotation of ATP be a quite difficult job. In addition to, many researchers assumed ATP model with integer time. However, in industry practices, integer times are very rare and the model developed using integer times is therefore approximating the real system. Various alternative models for an ATP system with time lags have been developed and evaluated. In most cases, these models have assumed that the time lags are integer multiples of a unit time grid. However, integer time lags are very rare in practices, and therefore models developed using integer time lags only approximate real systems. The differences occurring by this approximation frequently result in significant accuracy degradations. To introduce the ATP model with time lags, we first introduce the dynamic production function. Hackman and Leachman's dynamic production function in initiated research directly related to the topic of this paper. They propose a modeling framework for a system with non-integer time lags and show how to apply the framework to a variety of systems including continues time series, manufacturing resource planning and critical path method. Their formulation requires no additional variables or constraints and is capable of representing real world systems more accurately. Previously, to cope with non-integer time lags, they usually model a concerned system either by rounding lags to the nearest integers or by subdividing the time grid to make the lags become integer multiples of the grid. But each approach has a critical weakness: the first approach underestimates, potentially leading to infeasibilities or overestimates lead times, potentially resulting in excessive work-inprocesses. The second approach drastically inflates the problem size. We consider an optimized ATP system with non-integer time lag in supply chain management. We focus on a worldwide headquarter, distribution centers, and manufacturing facilities are globally networked. We develop a mixed integer programming(MIP) model for ATP process, which has the definition of required data flow. The illustrative ATP module shows the proposed system is largely affected inSCM. The system we are concerned is composed of a multiple production facility with multiple products, multiple distribution centers and multiple customers. For the system, we consider an ATP scheduling and capacity allocationproblem. In this study, we proposed the model for the ATP system in SCM using the dynamic production function considering the non-integer time lags. The model is developed under the framework suitable for the non-integer lags and, therefore, is more accurate than the models we usually encounter. We developed intelligent ATP System for this model using genetic algorithm. We focus on a capacitated production planning and capacity allocation problem, develop a mixed integer programming model, and propose an efficient heuristic procedure using an evolutionary system to solve it efficiently. This method makes it possible for the population to reach the approximate solution easily. Moreover, we designed and utilized a representation scheme that allows the proposed models to represent real variables. The proposed regeneration procedures, which evaluate each infeasible chromosome, makes the solutions converge to the optimum quickly.

• Journal of Preventive Medicine and Public Health
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• v.16 no.1
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• pp.135-152
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• 1983

Emergency medical service is an important part of the health care delivery system, and the optimal allocation of resources and their efficient utilization are essentially demanded. Since these conditions are the prerequisite to prompt treatment which, in turn, will be crucial for life saving and in reducing the undesirable sequelae of the event. This study, taking the hyperbaric chamber for carbon monoxide poisoning as an example, is to develop a stochastic approach for solving the problems of optimal allocation of such emergency medical facility in Korea. The hyperbaric chamber, in Korea, is used almost exclusively for the treatment of acute carbon monoxide poisoning, most of which occur at home, since the coal briquette is used as domestic fuel by 69.6 per cent of the Korean population. The annual incidence rate of the comatous and fatal carbon monoxide poisoning is estimated at 45.5 per 10,000 of coal briquette-using population. It offers a serious public health problem and occupies a large portion of the emergency outpatients, especially in the winter season. The requirement of hyperbaric chambers can be calculated by setting the level of the annual queueing rate, which is here defined as the proportion of the annual number of the queued patients among the annual number of the total patients. The rate is determined by the size of the coal briquette-using population which generate a certain number of carbon monoxide poisoning patients in terms of the annual incidence rate, and the number of hyperbaric chambers per hospital to which the patients are sent, assuming that there is no referral of the patients among hospitals. The queueing occurs due to the conflicting events of the 'arrival' of the patients and the 'service' of the hyperbaric chambers. Here, we can assume that the length of the service time of hyperbaric chambers is fixed at sixty minutes, and the service discipline is based on 'first come, first served'. The arrival pattern of the carbon monoxide poisoning is relatively unique, because it usually occurs while the people are in bed. Diurnal variation of the carbon monoxide poisoning can hardly be formulated mathematically, so empirical cumulative distribution of the probability of the hourly arrival of the patients was used for Monte Carlo simulation to calculate the probability of queueing by the number of the patients per day, for the cases of one, two or three hyperbaric chambers assumed to be available per hospital. Incidence of the carbon monoxide poisoning also has strong seasonal variation, because of the four distinctive seasons in Korea. So the number of the patients per day could not be assumed to be distributed according to the Poisson distribution. Testing the fitness of various distributions of rare event, it turned out to be that the daily distribution of the carbon monoxide poisoning fits well to the Polya-Eggenberger distribution. With this model, we could forecast the number of the poisonings per day by the size of the coal-briquette using population. By combining the probability of queueing by the number of patients per day, and the probability of the number of patients per day in a year, we can estimate the number of the queued patients and the number of the patients in a year by the number of hyperbaric chamber per hospital and by the size of coal briquette-using population. Setting 5 per cent as the annual queueing rate, the required number of hyperbaric chambers was calculated for each province and for the whole country, in the cases of 25, 50, 75 and 100 per cent of the treatment rate which stand for the rate of the patients treated by hyperbaric chamber among the patients who are to be treated. Findings of the study were as follows. 1. Probability of the number of patients per day follows Polya-Eggenberger distribution. $$P(X=\gamma)=\frac{\Pi\limits_{k=1}^\gamma[m+(K-1)\times10.86]}{\gamma!}\times11.86^{-{(\frac{m}{10.86}+\gamma)}}$$ when$${\gamma}=1,2,...,n$$$$P(X=0)=11.86^{-(m/10.86)}$$ when $${\gamma}=0$$ Hourly arrival pattern of the patients turned out to be bimodal, the large peak was observed in $7 : 00{\sim}8 : 00$ a.m., and the small peak in $11 : 00{\sim}12 : 00$ p.m. 2. In the cases of only one or two hyperbaric chambers installed per hospital, the annual queueing rate will be at the level of more than 5 per cent. Only in case of three chambers, however, the rate will reach 5 per cent when the average number of the patients per day is 0.481. 3. According to the results above, a hospital equipped with three hyperbaric chambers will be able to serve 166,485, 83,242, 55,495 and 41,620 of population, when the treatmet rate are 25, 50, 75 and 100 per cent. 4. The required number of hyperbaric chambers are estimated at 483, 963, 1,441 and 1,923 when the treatment rate are taken as 25, 50, 75 and 100 per cent. Therefore, the shortage are respectively turned out to be 312, 791. 1,270 and 1,752. The author believes that the methodology developed in this study will also be applicable to the problems of resource allocation for the other kinds of the emergency medical facilities.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.99-111
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• 2018

In this study three target radionuclides ($^{60}Co$, $^{137}Cs$, and $^{125}Sb$) were reacted with solid samples collected from the nuclear facility sites to investigate their sorption and mobility behaviors for preparing unexpected nuclear accidents. The highest sorption distribution coefficients ($K_{ds}$) of target radionuclides ($^{60}Co=947mL/g$, $^{137}Cs=2105mL/g$, $^{125}Sb=81.3mL/g$) were found in topsoil layer under groundwater condition, and the $K_d$ values of three radionuclides decreased in the order of fractured rock and bedrock samples under the same groundwater condition. High $K_d$ values of $^{60}Co$ in topsoil layer and fracture rock resulted from the clay minerals present, and the $K_d$ values decreased 58-69 % under seawater condition due to high ionic strength. $^{137}Cs$ sorption was controlled by the ion exchange reaction with $K^+$ on flayed edge sites (FES) of mica. The $^{137}Cs$ sorption was the most affected by seawater (89-97 % decrease), while $^{125}Sb$ sorption was not much affected by seawater. As the results of column and batch experiments, the retardation factors (R) of $^{137}Cs$, $^{60}Co$, and $^{125}Sb$ were determined about 5400-7400, 2000-2500, and 250-415, respectively, indicating no significant transport for these radionuclides even in fractured zone with groundwater. These results suggest that even in the case of severe nuclear accident at the nuclear facilities the mobility of released radionuclides ($^{60}Co$, $^{137}Cs$, and $^{125}Sb$) can be significantly retarded by the topsoil layer and fractured rock. In addition, the results of this study will be used for the safety and environmental performance assessment of nuclear facilities.

• Spatial Information Research
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• v.20 no.2
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• pp.25-34
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• 2012

Air quality in Daegu area is lower compared to many other cities, since Daegu is a basin surrounded by mountains. Accordingly, the present study investigated the location of carbon monoxide(CO) monitoring stations for systematic CO pollution management on the basis of the CO emission distribution in Daegu area. In order to achieve this purpose, the location of CO monitoring stations, which can be used for the establishment of CO management, were assessed. Emission map in Daegu area was prepared using numerical map and Clean Air Policy Support System(CAPSS) data supplied by the M inistry of Environment. Average emissions were estimated by dividing emission sources into four subgroups(roadway, apartment, industry, and municipal incineration facility) according to legal division. The CO emission intensities were subdivided into 10, which a high number represents a high emission intensity, and the current monitoring stations were evaluated for the determination of their steps in CO emission intensities. As a result, additional installation of monitoring stations were suggested for the high CO emission areas rather than the low CO emission areas. A systematic CO management strategy would be established by the supplying various principle CO data when the CO monitoring stations are additionally installed at Kukwudong and other six sites on the basis of analyses of data obtained from 1999 to 2007.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.516-522
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• 2014

This study was conducted to investigate the impact of the anthropogenic factors affecting distribution of the Red-crowned Crane and White-naped Crane wintering in Cheorwon, Korea. Especially, it was investigated that the impact power and its range of the anthropogenic effect to the feeding flock density in cranes due to the paved road, residential area, military facilities and greenhouse density. The Red-crowned Crane and the White-naped Crane showed the similar preference and sensitivity against anthropogenic factors, because correlation of feeding flock density of the Red-crowned Crane and White-naped Crane was similar in the same site. The feeding flock density of the cranes near the residential area was lower than that of area far from the area, and tended to increase within 2.5 km distance. The increasing tendencies of feeding flock density from military facilities and high traffic volume road were similar, but the density in military facilities increased within 0.8 km, and the density from high traffic volume road increased within 2 km. This results suggested that military facilities and the road with high traffic volume made significant influence on foraging densities to the certain range. As the distance from the road with low traffic volume increased, feeding flock density tended to decrease. The area near the low traffic volume road had high feeding flock density because remaining rice grains were preserved by intermittent disturbances in that area. If the density of greenhouse is lower than $40/km^2$, feeding flock density in the low greenhouses density area was higher than high greenhouses density area. However, there was no difference in the feeding flock density if the density of the green houses is higher than $40/km^2$.

• Tunnel and Underground Space
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• v.16 no.1 s.60
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• pp.26-37
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• 2006

This study addresses the applicability of box fractal dimension, $D_B$, as an index of statistical homogeneity of fractured rock mass. The box-count method's capability in quantifying the combined effect of fracture density and size distribution is examined systematically. Total of 129 two-dimensional fracture configurations were generated based on different combinations of fracture size distribution and fracture density. $D_B$was calculated for the generated fracture network systems using the box-counting method. It was found that was standard deviation of trace length and fracture orientation have no effect on calculated $D_B$. The estimated $D_B$ was found to increase with increasing total density and/or mean trace length. To explore the field applicability of this study, the statistical homogeneity of fractured rock mass was investigated at the rock slope and the underground facility using the box-counting method as well as conventional contingency table analysis. The results obtained in this study clearly show that the methodologies given in this paper have the capability of determining the statistical homogeneity of fractured rock mass.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.2
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• pp.45-55
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• 2020

In terms of environmental justice, urban parks play a pivotal role in imperative amenities allowing for physical activity. The reasonable distribution of urban park services must be considered in terms of community demand and the context of the park. The purpose of this study is to analyze the inequity of qualitative park service according to the socioeconomic status(SES) in Daegu. The qualitative service was assessed for 82 neighborhood and walking-distance parks by utilizing the NGST(Neighborhood Green Space Tool). The inequity was analyzed by SES variables(ratio of basic living recipients, ratio of single-parent families, average housing sales, dilapidated dwelling ratio, and park area per capita). The features of the qualitative equity in Daegu is as follows. First, urban park planning in Daegu is in parallel with the development of residential areas rather than the local policy. The development pattern of parks stretching from center of the city to outskirts clearly dissociates the city based on socioeconomic status. The parks in the center are relatively old and poorly managed. Second, overall neighborhood parks lacked recreational facilities. The facilities are significantly influenced by the housing values around them. The lower the recreation facility score, the higher the floor gradient of the urban parks constraining physical activities. Third, the quantitative supply of parks has nothing to do with the quality of the urban parks. Green space distribution is highly dependent on natural park areas, so the park area per capita cannot be a standard for assessing qualitative equity.