• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.375-382
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• 2000

The surface hydrology of large watershed is susceptible to several preferred stable states with transitions between stable states induced by stochastic fluctuations. This comes about due to the close coupling of land surface and atmospheric interaction. An interesting and important issue is the duration of residence in each mode. In this study, mean transition tunes between the stable modes are analyzed for the Han River Basin. On the basis of historical data, the nonlinear water balance model is calibrated for the Han River Basin. The transition times between the stable modes in the model are studied based on the stochastic representation of the physical processes and on the calibrated model parameters. This study has implications for prediction of the transition time between stable modes or residence times, that is, the time the system spends in a given stable modes, since this would be equivalent to predicting the duration of drought or wet conditions.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.7
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• pp.64-73
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• 2002

This study was performed to evaluate effects of physical characteristics of both watershed and reservoir on nutrient-chlorophyll relationship in Korean reservoirs. Simple linear models were developed with published data in Korea including 415 reservoirs and 11 multi-purpose dams, and physico-chemical parameters of reservoirs and characteristics relationship of models were analyzed. Theoretical residence time in Korean reservoirs was strongly correlated with the ratio of TA/ST (drainage area + surface area / storage volume) in the logarithmic function. As a result of monthly nutrients-chlorophyll-a regression analysis, significant Chl-a-TP relationship appeared during May～July. The high Chl-a yields per total phosphorus appeared during this time (R$\^$2/=0.51, p<0.001, N= 1088). Chlorophyll-a demonstrated much stronger relationship with TP. than TN. Seasonal algal-nutrient coupling were closely related with N:P ratio in the reservoir water, and it was, in turn, dependent on the monsoon climatic condition (precipitation). Based on the results of regression analysis and high N:P ratio, a major limiting factor of algal growth appeared to be phosphorus during this time. Unlikely TA/ST ratio, DA/SA ratio (drainage area f surface area) was likely to influence directly on the nutrient-Chl-a relationship, indicating that if storage volume and inflowing water volume were the same, algal biomass could be developed more in reservoirs with large surface area. Thus, DA/SA ratio seemed to be an important factor to affect the development of algal biomass in Korean reservoirs. With low determination coefficient of TP-Chl-a relationship, our findings indicated not only nutrient (phosphorus) but also other physical factors, such as DA/SA ratio, may affect algal biomass development in Korean reservoirs, where actual residence time appears to be more closely related to reservoir surface area rather than storage volume.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.5
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• pp.577-583
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• 2007

To overcome certain disadvantages of past typical control techniques for toxic contaminants emitted from various industrial processes, the current study was conducted to establish a thermal catalytic system using mesh-type transition-metal platinum(Pt)/stainless steel(SS) catalyst and to evaluate catalytic thermal destruction of five chlorinated hydrocarbons[chlorobenzene(CHB), chloroform(CHF), perchloroethylene (PCE), 1,1,1-trichloroethane(TCEthane), trichloroethylene(TCE)]. In addition, this study evaluated the catalyst poison effect on the catalytic thermal destruction. Three operating parameters tested for the thermal catalyst system included the inlet concentrations, the incineration temperature, and the residence time in the catalyst system. The thermal decomposition efficiency decreased from the highest value of 100% to the lowest value of almost 0%(CHB) as the input concentration increased, depending upon the type of chlorinated compounds. The destruction efficiencies of the four target compounds, except for TCEthane, increased upto almost 100% as the reaction temperature increased, whereas the destruction efficiency for TCEthane did not significantly vary. For the target compounds except for TCEthane, the catalytic destruction efficiencies increased up to 30% to 97% as the residence time increased from 10 sec to 60 sec, but the increase of destruction efficiency for TCEthane stopped at the residence time of 30 sec, suggesting that long residence times are not always proper for thermal destruction of VOCs, when considering the destruction efficiency and operation costs of thermal catalytic system together. Conclusively, the current findings suggest that when applying the transition-metal catalyst for the better destruction of chlorinated hydrocarbons, VOC type should be considered, along with their inlet concentrations, and reaction temperature and residence time in catalytic system. Meanwhile, the addition of high methyl sulfide(1.8 ppm) caused a drop of 0 to 50% in the removal efficiencies of the target compounds, whereas the addition of low methyl sulfide (0.1 ppm), which is lower than the concentrations of sulfur compounds measured in typical industrial emissions, did not cause.

• IEMEK Journal of Embedded Systems and Applications
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• v.4 no.4
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• pp.174-179
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• 2009

Due to digital convergence, mobile embedded systems need more functionalities and a fully fledged OS. Applications for such embedded systems are linked with many shared libraries available in the OS and access a large data set at launch time. This results in increased application launch time. In this paper, we propose two techniques for reducing the application launch time: lazy-loading and pinning. Lazy-loading defers loading shared libraries that are not used in the application at launch time, whereas pinning guarantees the residence of shared libraries and data used at launch time in the main memory.

• Biotechnology and Bioprocess Engineering:BBE
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• v.7 no.3
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• pp.163-170
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• 2002

This report describes the use of a transtubular bioreactor to study the relative effects of diffusion versus perfusion of medium on antibody production by a hybridoma cell line. The study was performed with a high-density cell culture maintained in a serum-free, low-protein medium for 77 days. It was determined that the reactor possessed a macro-mixing pattern residence time distribution similar to a continuous stirred tank reactor (CSTR), However, due to the arrangement of the medium lines in the reactor, the flow patterns for nutrient distribution consist of largely independent medium path lengths ranging from short to long. When operated with cyclic, reversing, transtubular medium flow, some regions of the reactor (with short residence times) are more accessible to medium than others (with long residence times). From this standpoint, the reactor can be divided into three regions: a captive volume, which consists of medium primarily delivered via diffusion; a lapped volume, which provides nutrients through unilateral convection; and a swept volume, which operates through bilateral convection. The relative sizes of these three volumes were modified experimentally by changing the period over which the direction of medium flow was reversed from 15 min (larger captive volume) to 9 h (larger swept volume). The results suggest that antibody concentration increases as the size of the diffusion-limited (captive) volume is increased to a maximum at around 30 min with a sharp decrease thereafter. As reflected by changes in measured consumption of glucose and production of lactate, no significant difference in cellular metabolism occurred as the reactor was moved between these different states. These results indicate that the mode of operation of the transtubular bioreactor may influence antibody productivity under serum-free, low-protein conditions with minimal effects on cellular metabolism.

• Particle and aerosol research
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• v.8 no.4
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• pp.151-160
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• 2012

Health effects caused by the ultrafine particles in ambient air are great concern to the public health, and the strict measuring and monitoring of the ambient aerosol are required. In this work, the characteristics of the aerosol size distribution in Pohang province are studied. Optical particle counters (Grimm APS 1108 and 1109) were used to measure the aerosol size distribution in the area. Locations near the national monitoring site located in the industrial and the residence area were selected for the measuring sites of this study, and the locations in border area between the industry and the residence were selected for the reference of the comparison. In the industry site, it is found that the concentration of aerosol particles near the size of 5 ${\mu}m$ appear characteristically and the fluctuations in concentration with respect to time are minimal. The mass concentration of the aerosol above 10 ${\mu}m$ in diameter in the industry area was found to fluctuate significantly. The mass portion of $PM_{10}$ and PM2.5 to TSP in the residence area were 83% and 51% respectively. In the industrial regional, it was found that the mass portion of PM10 and $PM_{2.5}$ to TSP were 76% and 35% respectively. In the boundary area the mass portion of $PM_{10}$ and $PM_{2.5}$ to TSP were 78% and 54% respectively.

• Korean Journal of Community Nutrition
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• v.12 no.4
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• pp.381-395
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• 2007

For the purposes of participation in research projects, living in a laboratory has become popular among male university students who tend to have less opportunity for nutrition education and overestimate their own health, suggesting possibilities of many undesirable practices of lifestyle and dietary habits. Therefore, this study was conducted to investigate and compare health-related lifestyle practices, dietary habits, nutrition knowledge, food preference and dietary behaviors of the male university students according to residence type. The subjects were 260 (34, 15, 44, and 167, respectively for lab-living, self-boarding, dormitory and commuting) male engineering majors in the Gyeonggi area. Self-administered questionnaires consisted of general characteristics, health-related lifestyle practices, dietary habits, fast food consumption, nutrition knowledge, preference for foods and tastes, and self-examination of dietary behaviors. Lab-living subjects showed many undesirable practices, particularly with more smokers (p < 0.05), irregular eating (p < 0.01), overeating (p < 0.05) and skipping breakfast (p < 0.01), compared to the dormitory students and more time in computer/TV usage (p < 0.05), overeating (p < 0.05), more frequent use of fast-food (p < 0.05), less nutrition knowledge (p < 0.01) and less intake of milk/dairy products (p < 0.01) and fruits (p < 0.01), compared to commuting subjects. More smokers (p < 0.05) and irregular (p < 0.01) and unrelaxed meal times (p < 0.05), compared to the dormitory group, and less intake of fruits (p < 0.01) and dietary fiber (p < 0.01), compared to the commuting group were shown as undesirable practices of the self-boarding group. Therefore, continuous effort should be made to correct undesirable health- and diet-related practices found in this study in order to improve nutritional status as well as general health by developing a nutrition education program and contents of lectures focusing on more specific problems according to each subgroup such as lab-living and self-boarding male university students.

• Health Policy and Management
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• v.5 no.2
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• pp.104-126
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• 1995

This study was carried out to assess the utilization of urban health center and its related factors among the urban residents. The survey was carried out for 2,394 households in Taegu and Kyongju by the structured questionnaire from 28 March to 4 April and from 2 July to 9 July, 1994. Well trained interviewers visited 2,630 households in Taegu and Kyongju, and interviewed with housewives. Of the target households, 91.0%(2,394 households) were responded through three-time visiting. The major results were summarized as follows : The fourth and fifth decad utilized the health center more frequently than any other age groups.. The lower income group showed higher rate of health center utilization than those in higher income group in Taegu City. The mean length of residence among residents of Kyongju City is longer than those of Taegu City, and the longer length of residence, the higher rate of the health center utilization. Those who are living together with neonate and infant or elderly people showed higher rate of health center utilization than those who are living without neonate and infant or elderly people in both Taegu and Kyongju. The most common reason for visiting the health center was 'low cost'. The major reasons for not visiting the health center were 'not regular customer', 'poor health center facility', and 'low quality of care'. Vaccination, communicable disease control, outpatient care, public hygiene, maternal and child health program were well recognized as health center activities. In logistic regression for the utilization of health center, the significant independent variables were length of residence and recognize the site of health center in both Taegu and Kyongju. The improvement of quality of health service, physical environment of health center and public relations on health center's activities shoulod be considered for reactivation and reingorcement of health center functions.

• Journal of the Economic Geographical Society of Korea
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• v.16 no.2
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• pp.167-181
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• 2013

The cross-border flow of workers in EU having the freedom of labor mobility and residence plays a role in the border labor markets as a structural factor of regulation. The regulation role of the cross-border flow of workers on the Grand R$\acute{e}$gion, which is the border among the France-Belgium-Luxemburg-Germany, is as follows. First, the cross-border flow of workers regulates the regional surplus and lack of labor in quantity and quality. Second, the border labor markets are regulated by the regionally segmented supply and demand of labor and are modulated by the flexible employment like a part-time and temporary employment. Third, the residence of the cross-border workers concentrates on the adjacent regions to the border. And the atypical cross-border workers, who have their residence in the neighboring country but works in the existing country, are rising rapidly.

• Korean Journal of Human Ecology
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• v.23 no.4
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• pp.721-732
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• 2014

The purpose of this study was to investigate the dietary behavior and late-night eating habit of university students in Daejeon. Questionnaires were collected from 432 students and statistically analyzed according to residence type. One thirds of students took meals irregularly and skipped breakfast because of no time. Both Relative self-boarding and dormitory boarding group skipped breakfast more frequently than home group(p<0.01). The carbonated drink was most frequently chosen during late-night eating. The most favorite alcoholic beverage was soju and 54.7% of students drank soju 1~2 times per week near campus. Almost half of them took late-night foods 1~2 times per week at home(51.8%), near campus(25.8%), near home(15.6%), down town(6.9%). The percentage of late-night eating near campus was higher in dormitory boarding group than both home group and relative self-boarding group(p<0.001). Late-night foods were selected based on taste in 1~2 man won and enjoyed with 2~3 friends until 12 pm. The more in relative self-boarding group chose late-night foods based on taste than both home and dormitory boarding group(p<0.05). The main intake method for late-night foods was delivery. The results of this study suggest that nutritional education is required for relative self-boarding group to change dietary behavior and to select proper late-night foods for their health.