• Journal of Environmental Health Sciences
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• v.27 no.2
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• pp.51-59
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• 2001

Song stream is located in the upstream of the Namhan River. Normal times, the stream flows down to the east sea through the drainage pipe but at rainy season, it flows to the Namhan River. There are large stock farm, leisure town and cultivated land in this basin. The pollutants from these contamination source cause eutrophication at lake Doam and deterioration of water quality in namdai stream. In this case, this study was carried out to evaluate water quality and environmental capacity as well as economical efficiency of each industry. The basin shape factor of subject stream was 0.315, slope is higher than usual basin. The BOD, T-N and T-P productive contamination loading from each contamination source was 2,690, 974 and 194 kg/day, respectively, and major contamination source was stock farm and cultivated land. Annual BOD, T-N, T-P distribution(median value) of Song stream showed 1.0~2.2 mg/L, 3.16~5.85 mg/L and 0.024~0.197 mg/L Doam lake showed 1.1~1.9, 2.51~3.89 and 0.042~0.114 mg/L, respectively. Being compared of water quality at main stream between past and present, it showed that the water quality has improved since last five years. BOD improvement rate was 8~50%. Run off loading of BOD, T-N, T-P was 366, 1129, 17.2 kg/day, and run off rate was 13.6%, 86.2%, 11.3% respectively. Finally, the result of productivity survey of each industry, leisure town, cultivated land and large stock farm was 118, 46, 50 billion won, per T-P 1kg productive, and productivity portion was 100, 39, 42% respectively, and the highest economical efficiency industry was leisure facilities.

• Korean Journal of Health Education and Promotion
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• v.23 no.5
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• pp.29-46
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• 2006

Purpose: Since 1994, Asian Health Services, the Korean American Community Advisory Board, and the Center for Family and Community Health (University of California at Berkeley) have conducted periodic, population-based surveys on Korean American community health in Alameda County, California. The present study examines changes in health care access and utilization between 1994 and 2002 among Korean American adults in Alameda County, California. Method: We reanalyzed data from the 1994 and 2002 Korean Health Surveys. The primary variables of interest, health care access and utilization, were operationalized in terms of health insurance coverage, routine check-ups, a usual source of health care and reported barriers to health care. The frequency distribution of each indicator was calculated and its standard error was estimated using SUDAAN. The differences between 1994 and 2002 were examined with chi-square test. Results: Compared to 1994, Korean Americans in Alameda County were more likely to have health insurance coverage in 2002 (74.0% vs. 82.7%). Korean Americans in Alameda County were more likely to have received a recent (prior two years) routine health checkup in 2002 (50.4% vs. 57.2%). Health checkups increased over time for males, for adults with more than 12 years of education, and for employed adults. Also, compared to 1994, employed adults were more likely to have a usual source of health care in 2002 (66.5% vs. 78.4%). In both 1994 and 2002, high cost (58.0% vs. 47.8%) was the most commonly cited barrier to health care, and the next most frequently cited barriers were language (29.2% vs. 27.7%) and no time (29.2% vs. 30.3%). Conclusion: To improve health care utilization and health conditions, it is important to investigate factors related to health care and to monitor changing trends. Ongoing surveillance of health-related factors can contribute to the development of health education programs to reduce morbidity and mortality due to chronic disease, and thereby lead to improvements in health status among Korean Americans.

• Journal of Magnetics
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• v.7 no.3
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• pp.63-71
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• 2002

Three fabrication techniques for forming thin barrier layer with uniform thickness and large barrier height in magnetic tunnel junction (MTJ) are discussed. First, the effect of immiscible element addition to Cu layer, a high conducting layer generally placed under the MTJ, is investigated in order to reduce the surface roughness of the bottom ferromagnetic layer, on which the barrier is formed. The Ag addition to the Cu layer successfully realizes the smooth surface of the ferromagnetic layer because of the suppression of the grain growth of Cu. Second, a new plasma source, characterized as low electron energy of 1 eV and high density of $10^{12}$ $cm^{-3}$, is introduced to the Al oxidation process in MTJ fabrication in order to reduce damages to the barrier layer by the ion-bombardment. The magnetotransport properties of the MTJs are investigated as a function of the annealing temperature. As a peculiar feature, the monotonous decrease of resistance area product (RA) is observed with increasing the annealing temperature. The decrease of the RA is due to the decrease of the effective barrier width. Third, the influence of the mixed inert gas species for plasma oxidization process of metallic Al layer on the tunnel magnetoresistance (TMR) was investigated. By the use of Kr-O$_2$ plasma for Al oxidation process, a 58.8 % of MR ratio was obtained at room temperature after annealing the junction at $300{^{\circ}C}$, while the achieved TMR ratio of the MTJ fabricated with usual Ar-$0_2$ plasma remained 48.4%. A faster oxidization rate of the Al layer by using Kr-O$_2$ plasma is a possible cause to prevent the over oxidization of Al layer and to realize a large magnetoresistance.

• Journal of Radiation Protection and Research
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• v.22 no.3
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• pp.143-151
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• 1997

As the pulse heights from a NaI(Tl) detector vary with the temperature of the measuring environment a significant change in temperature may affect the energy calibration of the spectrometer. The auto-adjustment of the channel corresponding to a pulse heights can be achieved by introducing an external reference source to compensate the temperature dependency of pulse heights, but unfavorable increases of the Compton continuum are caused due to the external source. In this study, the total absorption peaks dominant in the typical environmental gamma spectrum-239 keV from $^{212}Pb$, 351 keV from $^{214}Pb$, 1460 keV from $^{40}K$ and 2614 keV from $^{208}Tl$ for examples - were used as reference in the correction of energy calibration. With these peaks, the program to calibrate the energy of the s spectrum was developed using Microsoft Visual Basic language. The program developed here was applied to the environmental spectra measured at intervals of 30 minutes in the temperature range of from $-20^{\circ}C$ to $10^{\circ}C$ to demonstrate the validity and applicability. As a result of the test, the correction scheme appeared to be effective in the temperature changes encountered in the usual environment.

• The Journal of the Acoustical Society of Korea
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• v.27 no.1
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• pp.40-46
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• 2008

Weak target detection and localization in the presence of loud surface ship noise is a critical problem for matched field processing (MFP) in shallow water. For stationary sources, each signal component of received signal can be separated and interference can be suppressed using eigen space analysis schemes. However, source motion, in realistic cases, causes spreading of signal energies in their subspace. In this case, eigenvalues of target and interfere signal components are mixed and hard to be separated with usual phone space eigenvector decomposition (EVD) approaches. Our technique is based on mode space and utilizes the difference in their physical characteristics of surface and submerged sources. Performing EVD for modal cross spectral density matrix, interference components in the mode amplitude subspace can be classified and eliminated. This technique is demonstrated with synthetic data, and results are discussed.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.189-197
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• 2012

It is usual for test data generation to be performed using either high-level specifications or source codes written in high-level programming languages. In certain circumstances, however, such information is not always available. This paper presents a technique that generates test data based on executable object codes. The proposed technique makes use of a very simple function minimization technique without sophisticated object code analysis and produces test data dynamically. We have conducted a simple experiment to evaluate the effectiveness of the proposed test data generation technique with a triangle classification program to show that branch coverage can be easily achieved.

• Journal of Korean Society for Atmospheric Environment
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• v.30 no.1
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• pp.26-36
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• 2014

The uncertainty assessment is important to improve the reliability of emission inventory data. The DARS (Data Attribute Rating System) have recommended as the uncertainty assessment technic of emission inventory by U.S. EPA (Environmental Protection Agency) EIIP (Emission Inventory Improvement Program). The DARS score is based on the perceived quality of the emission factor and activity data. Scores are assigned to four attributes; measurement/method, source specificity, spatial congruity and temporal congruity. The resulting emission factor and activity rate scores are combined to arrive at an overall confidence rating for the inventory. So DARS is believed to be a useful tool and may provide more information about inventories than the usual qualitative grading procedures (e.g. A through E). In this study, the uncertainty assessment for 2009 CAPSS (Clean Air Policy Support System) emission inventory is conducted by DARS. According to the result of this uncertainty assessment, the uncertainty for fugitive dust emission data is higher than other sources, the uncertainty of emission factor for surface coating is the highest value, and the uncertainty of activity data for motor cycle is the highest value. Also it is analysed that the improvement of uncertainty for activity data is as much important as the improvement for emission factor to upgrade the reliability of CAPSS emission inventory.

• Health Policy and Management
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• v.4 no.2
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• pp.58-76
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• 1994

In order to study factors affecting the use of the ambulatory physician services. Andersen's model for health utilization was modified by adding the health behavior component and examined with three different approaches. Three different approaches were the multiople regression model, logistic regression model, and LISREL model. For multiple regression, dependent variable was reported illness-related visits to a physician during past one year and independent variables are variaous variables measuring predisposing factor, enabling factor, need factor and health behavior. For the logistic regression, dependent variable was visit or no-visit to a physician during past one year and independent variables were same as the multiple regression analysis. For the LISREL, five endogenous variables of health utiliztion, predisposing factor, enabling factor, need factor, and health behavior and 20 exogeneous variables which measures five endogenous variables were used. According to the multiple regression analysis, chronic illness, health status, perceived health status of the need factor; residence, sex, age, marital status, education of the predisposing factor ; health insurance, usual source for medical care of enabling factor were the siginificant exploratory variables for the health utilization. Out of the logistic regression analysis, health status, chronic illness, residence, marital status, education, drinking, use of health aid were found to be significant exploratory variables. From LISREL, need factor affect utilization most following by predisposing factor, enabling factor and health behavior. For LISREL model, age, education, and residence for predisposing factor; health status, chronic illess, and perceived health status for need factor; medical insurance for enabling factor; and doing any kind of health behavior for the health behavior were found as the significant observed variables for each theoretical variables.

• Korean Journal of Optics and Photonics
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• v.15 no.2
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• pp.158-170
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• 2004

Wireless optical communication is expected for high-speed optical communication in the areas of saturated optical fiber communication and low population density. In this paper, we present an optical transmitter system for wireless optical communication with new design concepts different from the usual optical imaging system. The specifications are the following: the source is a laser diode(LD) of wavelength 830 nm in which the divergent angle from the tangential plane differs from that from the sagittal plane. Here, the requested transmission distances are very long range such as 500 m to 1500 m and beam diameter is 3 m at the receiver with symmetrical energy distribution. For the evaluation characteristics of this kind of non-imaging system, two optical quantities, the relative illumination distribution and energy transfer efficiency, are numerically calculated through lots of ray tracing.

• Journal of Nutrition and Health
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• v.25 no.2
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• pp.140-149
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• 1992

It was hypothesized that variations within the range of usual calcium(Ca) and sodium(Na) intakes of Korean influence bone mineral density(BMD) in healthy premenopausal women The relationship of nutrient intake urinary excretion physical activity and circulating IGF-1 level with spine({{{{ { L}_{2 } }}}}-{{{{ { L}_{4 } }}}}) and femur BMD was determined in 47 normal premenpausal women. There was a positive relationship between BMD of the lumbar spine and body weight. The BMD of femoral neck was positively correlated with Ca and protein intakes from animal source and circulating IGF-1 level. There was a negative relationship between femur BMD and both Na intake and urinary excretion. The complex interrelations between femur BMD regression analysis, From this analysis. Ca intake from animal origin was the only significnat Premenopausal women of femur BMD. In the basis of femur BMD three groups were divided Premenopausal women of femur BMD$\leq$0.84g/cm2 showed depressed Ca intake of animal origin in later and early life and enhanced urinary Na excretion compared to women of femur study suggests that dietary Ca is a major constituent affecting femur BMD because of a decrease in net Ca absorption and an increase in urinary Ca loss.