• Archives of Pharmacal Research
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• v.20 no.1
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• pp.24-28
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• 1997

In the present study, a pharmacokinetic model to address the effects of the diffusional barrier between splanchnic bed and enterocytes on the extent of presystemic and systemic intestinal elimination of drugs was developed. The model is composed of five compartments, ie., gut lumen, enterocyte, splanchnic bed, liver and central compartments. The equations for various pharmacokinetic parameters important for estimating the quantitative differences between presystemic and systemic intestinal and hepatic elimination of drugs were derived. A simulation study demonstrated that the diffusions[ barrier present between splanchnic blood and enterocytes can have significant effects on oral bioavailability and systemic clearance of drugs. In conclusion, the model can be useful for a better understanding of the effects of diffusional barrier on the extent of administration-route dependent intestinal and hepatic elimination of drugs, especially those with high hydrophilicity and/or charge(s) under physiological conditions.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.227-227
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• 2010

The intercalation chemistry of graphite presents an attractive route to obtain few-layered graphene platelets based on the expanded interlayer spacing. We report that the lithium can be intercalated into the graphite in a controllable manner by adjusting the variables such as temperature, pressure, and reaction time. From the X-ray diffraction experiments, the lithium-graphite intercalaltion compounds (Li-GICs) can be produced as the first stage compounds ($LiC_6$), the second-stage compounds ($LiC_{12}$), and the mixtures, which is most likely to be dependent on the temperature and reaction time. Since these Li-GICs are expected to facilitate the exfoliation of graphite, we investigated the feasibility of Li-GICs as a effective precursors for the generation of single-or few-layered graphite nano-platelets.

• Fire Science and Engineering
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• v.3 no.2
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• pp.11-19
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• 1989

In this study, the independent variables are the floor plan configulation. The dependent variables are the occupant's egress behavior, especially spatial movement pattern, and life - safety performance of building. Fire events were simulated on single story of office building. Simulation run for allowable secaping thime(180 seconds) arbitrarily selected, and involved 48 occupants. The major findings Pre as follows. 1) Computer simulation model suggested in this study can be used as the Preoccupancy evaluation method of the life-safety performance for architectural design based on prediction of occupants' egress behavior in the levels of validity and sensitivity, 2) Sucess or failure in occupants' escape is determined by decreasing walking speed caused by jamming at exits or over crowded corridor, and increasing route length caused by running about in confusion at each subdivision and corridor. 3) In floor plan configuration which safe areas located at the extreme ends of the corridor, cellular floor planning have to be avoided preventing jamming and running about in confusion at overcrowded corridor.

• Journal of Family Resource Management and Policy Review
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• v.12 no.4
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• pp.15-33
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• 2008

The purpose of this ethnography is to describe and analyze the employment and substitutional use of daily help for the household work. Ten housewives and one educator of daily help from Gwangju City were interviewed with an unstructured questionnaire. They experience many difficulties from this daily help employment and use, even though they gain some basic help from their service. The diversity of the routes to seek out this daily help means that there is no proper route. And the daily help's sudden quit causes many realistic and psychological problems. Frequent disagreement between the user's demand and help's implement comes from communication failure. Three different management patterns of daily help were issued ; 'conservative-dominant', 'rational-mandatory', 'powerless-dependent'.

• Proceedings of the KOR-KST Conference
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• 2000.02a
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• pp.89-115
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• 2000

Traffic signal setting policies and traffic assignment procedures are mutually dependent. The combined signal control and traffic assignment problem deals with this interaction. With the total travel time minimization objective, gradient based local search methods are implemented. Deterministic user equilibrium is the selected user route choice rule, Webster's delay curve is the link performance function, and green time per cycle ratios are decision variables. Three implemented solution codes resulting in six variations include intersections operating under multiphase operation with overlapping traffic movements. For reference, the iterative approach is also coded and all codes are tested in four example networks at five demand levels. The results show the numerical gradient estimation procedure performs best although the simplified local searches show reducing the large network computational burden. Demand level as well as network size affects the relative performance of the local and iterative approaches. As demand level becomes higher, (1) in the small network, the local search tends to outperform the iterative search and (2) in the large network, vice versa.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2003.05a
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• pp.181-182
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• 2003

Exposure to some synthetic environmental chemicals and their metabolites cause reproductive problems in a variety of vertebrate via endocrine mechanisms. However, in most cases, the link between these compounds and adverse effects on humans, fish, and wildlife has not been established, which necessitates a closer look at the molecular, functional, and clinical implications of these chemicals in the environment. Calbindin-D9k (CaBP-9k) is a member of a largo family of intracellular calcium binding proteins that have high affinities for calcium. It was reported that the estrogen level of uterus affected the expression of the CaBP-9k gene in rat uterus. We examined the dose-dependent CaBP-9K gene expression in the uterus for three-days injection of methoxychlor (HC) in the overectomized immature rats and the relation with uterotrophic response of the compoundsand compared the responses induced by MC according to the route of administration.

• Journal of Navigation and Port Research
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• v.30 no.6 s.112
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• pp.427-432
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• 2006

The purpose of the present study was to investigate the effect of mariner's situation awareness(SA) training on navigation performance using a full mission ship-handling simulator. For this purpose, the mariners were trained in terms of various aspects of SA. Independent variables such as risk levels of ship-to-ship collision, navigational route types of 'target ship(TS)', and number of ships around the own ship(OS) were systematically varied, and dependent variables of closest point of approach(CPA) between TS and OS, number of collision, types of collision-avoidance strategy were measured The results can be summarized as followings. First, training on mariner's SA appeared to induce improved performances in various aspects of ship handling. Second, mariners in the routine navigation situation where TS had priority following maritime rules seemed to suffer to prepare collision avoidance when the TS altered its route. However, this tendency greatly reduced after the training These results suggest the benefit of mariner's SA training on maritime safety.

• YAKHAK HOEJI
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• v.36 no.3
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• pp.212-219
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• 1992

Although oral route is the most convenient route for drug administration, the short and variable transit of drug through GI tract restricts the sustained drug absorption after oral administration. Thus, for sustained absorption of drugs, it is desirable to prolong the GI transit time by retaining the dosage forms in the stomach. In this study, the enzyme-digestible swelling hydrogel was synthesized by heating the mixed solution of N-vinyl-2-pyrrolidone[monomer], acrylated albumin[crosslinking agent] and proxyphylline[drug] at $65^{\circ}C$ for 10 hours in the cylindrical test tube. The resultant hydrogel tablet (diameter; 0.77 cm, thickness; 0.47 cm) was designed to swell in the gastric fluid after oral administration to such a size that passing through the pylorus could be inhibited during the drug release. After releasing drug, the hydrogel was expected to be degraded by pepsin, an enzyme in the stomach, and eventually solubilized. Actually, the hydrogel synthesized in the study swelled to a size larger than the diameter of the pylorus ($1.3{\pm}0.7$ cm) and slowly digested in the presence of pepsin. Drug release from the hydrogel was prolonged up to about 12 hours. The swelling kinetics was dependent on albumin acrylation time, drug content and gel thickness. Particularly the gel thickness was the most important factor that influences on drug release. By adjusting these factors, the albumin-crosslinked hydrogel was expected to be retained in the stomach for up to 60 hours and used as a potential platform of drugs for long-term GI absorption.

• The Journal of Information Systems
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• v.29 no.2
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• pp.287-306
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• 2020

Purpose Youth unemployment is a social problem that continues to emerge in Korea. In this study, we create a model that predicts the employment of college graduates using decision tree, random forest and artificial neural network among machine learning techniques and compare the performance between each model through prediction results. Design/methodology/approach In this study, the data processing was performed, including the acquisition of the college graduates' vocational path survey data first, then the selection of independent variables and setting up dependent variables. We use R to create decision tree, random forest, and artificial neural network models and predicted whether college graduates were employed through each model. And at the end, the performance of each model was compared and evaluated. Findings The results showed that the random forest model had the highest performance, and the artificial neural network model had a narrow difference in performance than the decision tree model. In the decision-making tree model, key nodes were selected as to whether they receive economic support from their families, major affiliates, the route of obtaining information for jobs at universities, the importance of working income when choosing jobs and the location of graduation universities. Identifying the importance of variables in the random forest model, whether they receive economic support from their families as important variables, majors, the route to obtaining job information, the degree of irritating feelings for a month, and the location of the graduating university were selected.

• Journal of Ocean Engineering and Technology
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• v.20 no.3 s.70
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• pp.45-53
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• 2006

Each year, the south coast of Korea is badly damaged from storm surge. The damages are greatly dependent upon the local peculiarities of the region where the storm surge occurs. So, in order to prevent/reduce recurrence of the disaster, it is very important to investigate the fluctuation characteristics of the storm surge height, related to the local peculiarities at each coastal area where occurrence of the disaster is expected. In this paper, using the numerical model, the storm surge was simulated to examine its fluctuation characteristics at the Gyeongnam coast (southeast coast of Korea). Typhoons of Sarah (5914), Thelma (8705) and Maemi (0314), which caused terrible damage to the coastal area in the southeast coast of Korea in the past, were used forstorm surge simulations. Moreover, the storm surge due to virtual typhoons, which were combined the characteristics of each proposed typhoons (Maemi, Sarah, Thelma)with the travel route of other typhoon, was predicted. As expected, the results revealed that the storm surge heights are enhanced at the coastal regions with the concavity like a long-shaped bay. Also, the storm surge heights, due to each typhoon, were compared and discussed at major points along the Gyeongnam coast, related to the local peculiarities, as well as the characteristics and the travel route of typhoon.