• Fire Science and Engineering
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• v.34 no.4
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• pp.78-86
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• 2020

In this study, numerical simulations were performed on the air egress velocity of pressurization systems in an ancillary room when a fire occurred in an apartment house. The relationship between the air supply flow rate of a damper and air egress velocity at a fire door is predicted to be linear. Additionally, a minimum flow rate of the damper, which meets national fire safety standards for air egress velocity, i.e., 0.7 m/s can be estimated. Air egress velocity at the fire door is analyzed according to the supply air direction and installation height of the damper. When the damper has an upward supply air direction and is installed at a high level, the egress velocity at the top section of the fire door is larger, whereas the soot concentration at the ancillary room is lower than when the supply direction of the damper is downward. Therefore, it is found that increasing the air egress velocity at the top section of the fire door helps to efficiently prevent the inflow of smoke.

• Resources Recycling
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• v.23 no.3
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• pp.51-60
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• 2014

In this study, the domestic supply & demand of the raw materials of 35 rare metals was analyzed categorized as four types - ores, metals, compounds and scraps. Foreign trade volumes of the raw materials of rare metals have been steadily increased, furthermore, recently trade growth rate highly exceeds GDP. The raw materials of rare metals - silicon, nickel, molybdenum, manganese, etc. - for steel industry were the most big part of the raw materials of rare metals trade, while the raw materials of rare metals for electronics industry were imported relatively small volumes less than $100 million. However systematic supply & demand management on the raw materials of rare metals for electronics industry is needed since recently growth rate per year has been remarkably high over 20%. Import volumes were about three times bigger than export scale, and most of the raw materials of rare metals were traded as a metal form.

• The Journal of Korean Medicine
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• v.20 no.2
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• pp.27-36
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• 1999

This study was performed to investigate the supply and demand of the oriental medical doctor(OMD) based on the supply and demand analysis of OMD up to the year 1997. The baseline projection and demographic methods were considered to examine the supply of OMD. On the contrary, for the demand analysis, two different approaches were conducted with the nonlinear regression model. The findings of this study indicate that the OMD will be oversupplied before the year 2012 with decreasing rate. However, when we consider the demand of OMD in the future. it is anticipated that the demand of oriental medicine will be increased rapidly with two major aspects. The first is the expansion of insurance benefits. The second is the increasing number of adult diseases because of the aging of the population structure. Therefore, the effective cooperation system and mutual exchange between western and oriental medicine is required for the future. Also. it is necessary to make the oriental medicine of the pharmaceutical services in more scientific way for the appropriate policy of the demand and supply of OMD. For the future study, the students who study abroad, especially China should be considered. These students will be the key element for the future supply of OMD.

• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.3
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• pp.51-70
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• 2013

This paper develops a model to predict the adoption and level of usage of network technology in a two-level supply chain with buyer-supplier relationships. A firm's adoption of a new technology depends not only on its own beliefs of the new technology's costs and benefits, but also on the adoption decisions of other firms in the supply chain. A model first analyzes an individual supplier's decision about a new technology adoption considering with multiple suppliers and buyers. Individual suppliers' decisions are aggregated with a population model to project how new technology diffuses across the supply chain and examine the pattern of diffusion process. This study found that as more firms adopt in initial periods, the total amount of information to the potential adopters in the population increases, and then the number of firms persuaded by the information increases as the process moves up the distribution of adoption process. We consider three factors influencing the diffusion speed of the new technology in a supply chain network : mean benefits, cost sharing, and information provision. This study examines how such factors affect the reduction of threshold levels, which implies that reductions in threshold levels have an aggregate effect by accelerating the rate of adoption. In particular, we explore relationship factors available in practice in a buyer-supplier relationship and numerically examines how these relationship factors contribute to increase the diffusion speed of the technology in a two-level supply chain.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.4
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• pp.29-37
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• 2017

This papers focuses on remanufacturing processes in a closed loop supply chain. The remanufacturing processes is considered as one of the effective strategies for enterprises' sustainability. For this reason, a lot of companies have attempted to apply remanufacturing related methods to their manufacturing processes. While many research studies focused on the return rate for remanufacturing parts as a control parameter, the relationship with demand certainties has been studied less comparatively. This paper considers a closed loop supply chain environment with remanufacturing processes, where highly fluctuating demands are embedded. While other research studies capture uncertainties using probability theories, highly fluctuating demands are modeled using a fuzzy logic based ambiguity based modeling framework. The previous studies on the remanufacturing have been limited in solving the actual supply chain management situation and issues by analyzing the various situations and variables constituting the supply chain model in a linear relationship. In order to overcome these limitations, this papers considers that the relationship between price and demand is nonlinear. In order to interpret the relationship between demand and price, a new price elasticity of demand is modeled using a fuzzy based nonlinear function and analyzed. This papers contributes to setup and to provide an effective price strategy reflecting highly demand uncertainties in the closed loop supply chain management with remanufacturing processes. Also, this papers present various procedures and analytical methods for constructing accurate parameter and membership functions that deal with extended uncertainty through fuzzy logic system based modeling rather than existing probability distribution based uncertainty modeling.

• Journal of Distribution Research
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• v.7 no.1
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• pp.87-103
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• 2002

This study shows the effect of individual decision style on the Bullwhip effect of supply chain. There are four individual decision styles developed by Rowe and Boulgarides(1992). The analysis of the relationship between individual decision style and supply chain dynamics is focused on overshot against final consumer order rate. Multi methodologies are used to meet the goal of this study, which are survey, game and simulation. As a result of this study, the Bullwhip effect of supply chain isn't influenced by individual decision style. This study shows different result in comparision with the prior research results that individual fact affected the Bullwhip effect of supply chain, Therfore, it is important to improve supply chain infrastructure and system than the individual fact for decreasing the Bullwhip effect of supply chain.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.298-300
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• 2001

Haematococcus pluvialis was cultured autotrophically and mixotrophically for astaxanthin production in bubble column photobioreactors with $CO_2$ and/or acetate supplements. Four different schemes were tested using 5% $CO_2$ balanced with 95% $N_2$ at the aeration rate of 0.1 vvm and supplementation of acetate (l g/L) to the basal medium, MBBM. Average specific growth rates based on cell total volume of each case were 0.138 $day^{-1}$ in control (without $CO_2$ and acetate supplements), 0.125 $day^{-1}$ with only acetate supplementation, 0.315 $day^{-1}$ with only $CO_2$ supplement, 0.304 $day^{-1}$with both $CO_2$ and acetate. The growth rate under $CO_2$ supply was much higher than that without $CO_2$ supply. DCO and DO seemed to be a possible limitation factor. Another interesting observation was the growth rate under $CO_2$ supplement (without acetate) was higher than that under both $CO_2$ and acetate supply. This result is the opposite of the previously reported works. From the result, the existence of acetate may suppress the dark reaction of $CO_2$ fixation or photosynthesis. Conclusively, the growth of H. pluvialis under photoautotrophic condition found to be higher than that under mixotrophic condition.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.1
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• pp.34-39
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• 2005

Trichloroethylene (TCE) is an environmental contaminant provoking genetic mutation and damages to liver and central nerve system even at low concentrations. A practical scheme is reported using toluene as a primary substrate to revitalize the biofilter column for an extended period of TCE degradation. The rate of trichloroethylene (TCE) degradation by Pseudomonas putida F1 at $25^{\circ}C$ decreased exponentially with time, without toluene feeding to a biofilter column ($11\;cm\;I.D.{\times}95\;cm$ height). The rate of decrease was 2.5 times faster at a TCE concentration of $970\;{\mu}g/L$ compared to a TCE concentration of $110\;{\mu}g/L$. The TCE itself was not toxic to the cells, but the metabolic intermediates of the TCE degradation were apparently responsible for the decrease in the TCE degradation rate. A short-term (2 h) supply of toluene ($2,200\;{\mu}g/L$) at an empty bed residence time (EBRT) of 6.4 min recovered the relative column activity by $43\%$ when the TCE removal efficiency at the time of toluene feeding was $58\%$. The recovery of the TCE removal efficiency increased at higher incoming toluene concentrations and longer toluene supply durations according to the Monod type of kinetic expressions. A longer duration ($1.4{\sim}2.4$ times) of toluene supply increased the recovery of the TCE removal efficiency by $20\%$ for the same toluene load.

• Journal of the Korean Solar Energy Society
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• v.40 no.1
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• pp.25-33
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• 2020

It has been reported about the energy saving performance of UFAD(under floor air distribution) system and NPC(night purge cooling) system respectively which are applied for commercial buildings. However, when two systems are used at the same time, the effect of heat transfer from floor plenum to slab may vary depending on the operating conditions of NPC. In this study, cooling energy demands were analyzed for building models with UFAD and NPC by using TRNSYS 17 program. UFAD was applied as a cooling system of the base building model, and the cooling energy demands were compared for 64 cases in which the operating time, supply airflow rate, and outdoor air temperature(T_o) of NPC. As a result, it was confirmed that the cooling energy demands were reduced to 30 ~ 80% level compared to UFAD alone, and in particular, the energy demand was reduced in proportion to the supply airflow rate or the operating time while T_o was 16 ~ 20℃. However, when T_o was 22℃, the increase in the supply airflow rate or the operating time results in a disadvantage in terms of cooling energy demands. In addition, the cooling energy demands for UFAD+NPC model were analyzed by applying weather data from three regions with different average outdoor air temperatures. As a result, the cooling energy demand of operating NPC only when T_o was below 20℃ was reduced by 27% compared to that of operating NPC continuously for 8 hours.

• Journal of Korean Society of Rural Planning
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• v.24 no.4
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• pp.47-55
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• 2018

Currently in the drought evaluation, which is a supplier-oriented standard that applies storage rates of reservoirs, evaluation for users that use agricultural water is not done. Therefore, this study established drought evaluation items for drought evaluation based on farmers' judgement, conducted a survey on farmers and experts, compared and analyzed weighted value between two groups, and then classified the evaluation standards per each evaluation item. The agricultural drought evaluation items are 5 major items of water supply lapse rate, agricultural weather, agricultural irrigation facility, crop and soil, and 12 subsections for regional characteristics and opinions of consumers that use water to be reflected. The result of analyzing weighted value of farmers and experts' major items shows that farmers is agricultural irrigation facility(0.219), water supply lapse rate(0.211), agricultural weather(0.204), crop(0.183) and soil(0.183). Experts is agricultural weather(0.297), agricultural irrigation facility(0.202), water supply lapse rate(0.189), crop(0.162) and soil(0.150), which displays difference between the two groups. The agricultural drought criteria standards are established based on precedent studies and cases, and grades of evaluation items are 1st grade(extreme stage), 2nd grade(warning stage), 3rd grade(alert stage) and 4th grade(attention stage). The above analysis per each consumer-oriented agricultural drought evaluation item and the analysis on the standards of evaluation grades are expected to be used as a basic resource for establishing agriculture drought policy and selecting drought area in the future.