• Sleep Medicine and Psychophysiology
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• v.22 no.2
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• pp.64-69
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• 2015

Objectives: We investigated whether sleep behaviors, severity of insomnia and circadian typology are associated with quality of life among Gyeongsang National University (GNU) medical students. Methods: Questionnaires were distributed to 46 fourth-year students of GNU Medical School. The hospital anxiety-depression scale, insomnia severity index (ISI), morningness-eveningness questionnaire (MEQ) and WHO Quality of Life-BREF (WHOQOL-BREF) were used. Results: Quality of life in terms of physical health was associated with age, weekday total sleep time (TST), weekend TST, catch up sleep, depression, ISI score, and MEQ score. Quality of life in terms of psychological health was correlated to weekday and weekend TST, anxiety, ISI score and MEQ score. Sex, weekday TST, depression, and ISI score were revealed to influence the social aspect of quality of life, and weekday and weekend TST, and ISI score were associated with quality of life in terms of environment. Multiple regression analysis showed that better sleep quality predicted to a higher quality of life in terms of physical, psychological and environmental health, and eveningness was associated with a better quality of life in terms of physical and psychological health. Conclusion: It is concluded that physical, psychological, and environmental aspects of quality of life were associated with quality of sleep and that physical and psychological aspects of quality of life were related to eveningness in GNU medical students. Therefore, it is equally important to treat emotional problem as well as improve sleep quality.

• Childhood Kidney Diseases
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• v.9 no.1
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• pp.31-37
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• 2005

Puruose : Thin glomerular basement membrane disease(TGBMD) is found in patients with family history of hematuria. TGBMD is autosomal dominant and is known to be one of the commonest causes of asymptomatic hematuria. This study was conducted to evaluate the histological and clinical features of patients with TGBMD. Methods : 150 cases diagnosed with TGBMD by renal biopsy while admitted in the department of pediatrics, Kyungpook National University Hospital between January 1999 and December 2003 comprised the study group. The following parameters were retrospectively anaIyzed age of onset, hematuria pattern, existence of proteinuria, process of diagnosis, laboratory findings, thickness and character of basement membrane and family history. Results : The mean age at the time of diagnosis was 7.9 years. The male to female ratio was 65:77. 94 patients or 66% visited the hospital with a chief complaint of persistent microscopic hematuria. Gross hematuria accounted for 13 cases or 9%. 78 cases(55%) were found to have hematuria for the first time from a routine school urinalysis screening. The renal biopsy showed the thickness of basement membrane to be 186$\pm$36 nm. Focal lamellation of the basement membrane was found in eight cases. In the family history, hematuria was shown in 10 cases on the Paternal side, 13 on The maternal side and none on both sides. In seven cases, hematuria was shown among siblings. No significant differences were found among the laboratory test results which were conducted at an average interval of fifteen months. Conclusion : TGBMD is one of the major causes of asymptomatic hematuria in children, which was diagnosed in increasing numbers since school urinary mass screening test started in 1998. In cases with familial progressive renal disease or focal duplication in the basement membrane Alport syndrome should be considered.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.287-291
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• 2010

In this study, a simple and rapid pre-treatment method based on liquid extraction was applied for the simultaneous determination of three macrolides (spiramycin, tylosin, and tilmicosin) residues. In these studies, the stock farm products was used as a matrix sample. When the liquid extraction method was compared with the solid phase extraction (SPE) method, the former showed higher recovery percentages and simpler steps than the latter. The macrolids were separated using a reverse-phase C18 ($250\;mm{\times}4.6\;mm$, $5\;{\mu}m$) column and a gradient elution with mobile phases consisting of phosphate buffer (pH 2.5) and acetonitrile. Tylosin and tilmicosin were detected at 288 nm and spiramycin was detected at 232 nm. The average recovery percentage ranged between 83.0-90.2% for samples spiked with the three macrolids at 50 and 100 ng/g The validation results showed that the limit of detection (7 (spiramycin), 12 (tilmiconsin), 12 (tylosin) ng/g)) was under the regulatory tolerances and the linearity from calibration curves was satisfactory for determining the multi-residue of three macrolids in farm products. Monitoring samples were collected at the main cities in Korea as Seoul, Busan, Deajeon, Incheon, Deagu, and Gwangju. Microlide antibiotics were not detected in most samples.

• Korean Journal of Remote Sensing
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• v.37 no.6_2
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• pp.1819-1827
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• 2021

Land-use/cover change caused by rapid urbanization in South Korea is one of the concerns in flood risk management because groundwater recharge by precipitation hardly occurs due to an increase in impermeable surfaces in urban areas. This study investigated the hydrologic effects of land-use/cover on groundwater recharge in the Yeonje-gu district of Busan, South Korea. A statistical time series analysis was conducted with temporal variations of precipitation and groundwater level to estimate lag-time based on correlation coefficients calculated from auto-correlation function (ACF), cross-correlation function (CCF), and moving average (MA) at five sites. Landform and land-use/cover within 250 m radius of the monitoring wells(GW01, GW02, GW03, GW04, and GW05) at five sites were identified by land cover and digital map using Arc-GIS software. Long lag-times (CCF: 42-71 days and MA: 148-161 days) were calculated at the sites covered by mainly impermeable surfaces(GW01, GW03, and GW05) while short lag-times(CCF: 4 days and MA: 67 days) were calculated at GW04 consisting of mainly permeable surfaces. The results suggest that lag-time would be one of the good indicators to evaluate the effects of land-use/cover on estimating groundwater recharge. The results of this study also provide guidance on the application of statistical time series analysis to environmentally important issues on creating an urban green space for natural groundwater recharge from precipitation in the city and developing a management plan for hydrological disaster prevention.

• The Korean Journal of Nuclear Medicine
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• v.38 no.6
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• pp.486-491
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• 2004

Purpose: factor analysis and independent component analysis (ICA) has been used for handling dynamic image sequences. Theoretical advantages of a newly suggested ICA method, ensemble ICA, leaded us to consider applying this method to the analysis of dynamic myocardial $H_2^{15}O$ PET data. In this study, we quantified patients' blood flow using the ensemble ICA method. Materials and Methods: Twenty subjects underwent $H_2^{15}O$ PET scans using ECAT EXACT 47 scanner and myocardial perfusion SPECT using Vertex scanner. After transmission scanning, dynamic emission scans were initiated simultaneously with the injection of $555{\sim}740$ MBq $H_2^{15}O$. Hidden independent components can be extracted from the observed mixed data (PET image) by means of ICA algorithms. Ensemble learning is a variational Bayesian method that provides an analytical approximation to the parameter posterior using a tractable distribution. Variational approximation forms a lower bound on the ensemble likelihood and the maximization of the lower bound is achieved through minimizing the Kullback-Leibler divergence between the true posterior and the variational posterior. In this study, posterior pdf was approximated by a rectified Gaussian distribution to incorporate non-negativity constraint, which is suitable to dynamic images in nuclear medicine. Blood flow was measured in 9 regions - apex, four areas in mid wall, and four areas in base wall. Myocardial perfusion SPECT score and angiography results were compared with the regional blood flow. Results: Major cardiac components were separated successfully by the ensemble ICA method and blood flow could be estimated in 15 among 20 patients. Mean myocardial blood flow was $1.2{\pm}0.40$ ml/min/g in rest, $1.85{\pm}1.12$ ml/min/g in stress state. Blood flow values obtained by an operator in two different occasion were highly correlated (r=0.99). In myocardium component image, the image contrast between left ventricle and myocardium was 1:2.7 in average. Perfusion reserve was significantly different between the regions with and without stenosis detected by the coronary angiography (P<0.01). In 66 segment with stenosis confirmed by angiography, the segments with reversible perfusion decrease in perfusion SPECT showed lower perfusion reserve values in $H_2^{15}O$ PET. Conclusions: Myocardial blood flow could be estimated using an ICA method with ensemble learning. We suggest that the ensemble ICA incorporating non-negative constraint is a feasible method to handle dynamic image sequence obtained by the nuclear medicine techniques.

• Journal of the Korean Vacuum Society
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• v.17 no.3
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• pp.226-233
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• 2008

The nucleation and evolution process of Ge nano-islands on Si(001) surfaces grown by chemical vapor deposition have been explored using atomic force microscopy (AFM). The Ge nano-islands are grown by exposing the substrates to a mixture of gasses GeH4 and H2 at pressure of 0.1-0.5Torr and temperatures of $600-650^{\circ}C$. The effect of growth conditions such as temperature, Ge thickness, annealing time on the shape, size, number density, and surface distribution was investigated. For Ge deposition greater than ${\sim}5$ monolayer (ML) with a growth rate of ${\sim}0.1ML/sec$ at $600^{\circ}C$, we observed island nucleation on the surface indicating the transition from strained layer to island structure. Further deposition of Ge led to shape transition from initial pyramid and hut to dome and superdome structure. The lateral average size of the islands increased from ${\sim}20nm$ to ${\sim}310nm$ while the number density decreased from $4{\times}10^{18}$ to $5{\times}10^8cm^{-2}$ during the shape transition process. In contrast, for the samples grown at a relatively higher temperature of $650^{\circ}C$ the morphology of the islands showed that the dome shape is dominant over the pyramid shape. The further deposition of Ge led to transition from the dome to the superdome shape. The evolution of shape, size, and surface distribution is related to energy minimization of the islands and surface diffusion of Ge adatoms. In particular, we found that the initially nucleated islands did not grow through long-range interaction between whole islands on the surface but via local interaction between the neighbor islands by investigation of the inter-islands distance.

• Journal of Korean Society of Forest Science
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• v.85 no.2
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• pp.288-299
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• 1996

This is the basic study to investigate the amount of transpirational water loss in thrifty mature Quercus mongolica stand by the heat pulse method. The differences of heat pulse velocity by direction and depth, differences of heat pulse velocity by dominant, codominant and suppressed trees, diurnal changes of heat pulse velocity due to the change of leaf water potential, vapor pressure deficit and radiation, and sap flow path way in sapwood by dye penetration were measured in stems. Finally the amounts of daily and annual transpiration in stand were calculated by the heat pulse velocity. The results obtained were summarized as follows : 1. Relationship between heat pulse velocity(V) and sap flow rate(SFR) was obtained as a equation of SFR=1.37V. 2. The sap flow rate was high in the order of dominant, codominant, and suppressed trees. The daily heat pulse velocity changed with radiation, temperature and vapor pressure deficit. 3. The heat pulse velocity showed the similar diurnal variation as the leaf water potential change. 4. The heat pulse velocity showed the highest value in May(4.0cm/hr in average), the lowest one in July(2.9cm/hr in average). 5. The heat pulse velocity in the same stem presented the highest value in the northern direction, medium in western, and the lowest in southern and eastern. 6. The heat pulse velocity in stem was highest in 0.5cm, medium in 1.0cm, and lowest in 1.5cm depth from the surface of stem. 7. The sap flow path way in stem showed sectorial straight ascent pattern in four sample trees. 8. The amount of sap flow(SF) was presented as a equation of $SF=1.37A{\cdot}V$(A: the cross-sectional area of sapwood, V: heat pulse velocity), and especially SF was larger in dominant tree than codominant and suppressed trees. 9. The amount of daily transpiration was 5.6ton/ha/day, and its composition ratio was 72% at day and 28% at night. 10. The amount of stand transpiration per month was largest in May(168ton/ha/month), lowest in July(125ton/ha/month). The amount of stand transpiration per year was 839ton/ha/year.

• Analytical Science and Technology
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• v.16 no.4
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• pp.283-291
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• 2003

Humic and fulvic acids present in soils of different depth were extracted and their acidic functional groups and structural characteristics were analyzed and compared. The purpose of this study was to present a basic data needed to evaluate the effect of humic substances on depth distribution and migrational behaviour of radioactive elements deposited on soil. Acidic functional groups of the humic and fulvic acids were analyzed by pH titration method, and their proton exchange capacity (PEC, $mq\;g^{-1}$) and average $pK_a$ values were obtained. Structural characteristics of the humic and fulvic acids were analyzed using their CPMAS $^{13}C$ NMR spectra and elemental composition data. pH titration data showed that fulvic acids have higher acidic functional group contents ranging from 5.5 to $7.0meq\;g^{-1}$ compared with that of humic acids ($3.8{\sim}4.8meq\;g^{-1}$). From depth profiles, it has been found that PEC values of humic acids in deeper soil (> 8 cm) were higher than those at the surface soils. Elemental compositions (H/C ratio) and spectral features ($C_{arom}/C_{aliph}$ ratio) obtained from CPMAS $^{13}C$ NMR spectra showed that the aromatic character in humic acids was a relatively higher than that of fulvic acids, while lower in carboxyl carbon content. The aromatic character and carboxyl carbon contents of humic acids tend to increase as soil depth increased, but those of fulvic acid showed little differences by the soil depth range.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.526-539
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• 2007

The purpose of this study is to investigate the influence of the Korean Wave on Chinese tourism to South Korea through a behavioral analysis of Chinese tourists in the general group package tours. China suppressed the needs of the Chinese people's geographical movement and imposed restrictions on information about the outside world with the use of a policy of "closure" for a long time. But since reforms and open-door policies were introduced in China, especially in the context of relaxation of control policies over Chinese outbound tourism after the mid-1990's, more and more Chinese make trips abroad including visits to South Korea. In this situation, the recent Korean Wave(especially, drama/film) describes the Korean national image by forming a bridge between fiction and reality and plays a pivotal role in broadening or reconstructing the geographical imagination of the Chinese people who have been historically isolated from the outside world. Although Chinese have imagined the Korean nationscape on the basis of geopolitical or economic factors in the past, they have currently broadened or reconstructed their geographical imagination to include socio-cultural factors related closely to the Korean way of life due to the recent Korean Wave. This newly constructed geographical imagination led by the Korean Wave functions as an important pulling factor in Chinese destination choices, affecting Chinese tourists' motivation formation and the recommendation of main attractions. The more influential the Korean Wave is on their destination choice, the more the respondents select the cultural factors in both their motivation for tourism to South Korea and their recommendations of tourism attractions to other people. Through the analysis results of both satisfaction and intention to revisit, the more influential the Korean Wave is on their destination choice, the higher is the degree of both satisfaction and intention to revisit. In other words, although Chinese tourism to South Korea is chiefly in the general group package tours, Chinese tourists who are influenced by Korean Wave on their destination choice have more attachment to(or affection for) Korea as a tourism destination. This result suggests that the Korean Wave affects qualitative change - that is, change of attitude - as well as quantitative change in Chinese demand for tourism to South Korea.

• Journal of the Korean Geographical Society
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• v.42 no.4
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• pp.540-559
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• 2007

The purpose of this paper is to analyse the locations and to interpret the landscapes of the local towns in Joseon Dynasty from Feng-shui's point of view. As a result of analysing the locations of towns in Gyeongsang Province, the towns which have typical Feng-shui landscapes make up to 58% of the total. Historically, the local towns that were established in the early period of the Joseon Dynasty didn't reveal Feng-shui's landscape, but those that were established in the late period of the Joseon Dynasty revealed the Feng-shui's landscape clearly. In this article, I classify the local towns of the Gyeongsang Province into 3 types: 1. Non Feng-shui type These towns are located near the seashore. The main reason that these towns were located at the seashore was defense against an enemy. 2. Semi Feng-shui type. These towns don't have natural location but have a man-made landscape, based on the principles of Feng-shui. 3. Typical Feng-shui type. These towns were typically administrational towns which were located at the center of a local region.