• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.568-570
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• 2009

Octadecyltrichlorosilane (OTS) self-assembled monolayer was selectively patterned by deep ultraviolet exposure, resulting in differential surface state, hydrophilic area with OTS hydrophobic surroundings. High-resolution (<10 ${\mu}m$) nanoparticulate Ag electrodes and organic semiconductors were patterned from simple dip-casting and ink-jetting on the pre-patterned hydrophilic surface, forming all solution-processed organic thin film transistors. The devices typically have shown a mobility of 0.065 $cm^2/V{\cdot}s$ and on-off current ratio of $8{\times}10^5$.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.415-416
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• 2007

HRTF DB, including the information of the sounds which is arrived to our ears, is generally used to make a 3D sound. But it can decline some three-dimensional effects by the confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that reduces the confusion of sound image localization. And we make use of an excitation energy by the sense of hearing. This method is brought HRTF spectrum characteristics into relief to draw out the energy ratio about the bark band and control low frequency band. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than the conventional methods.

• Journal of the Korean Geographical Society
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• v.42 no.1 s.118
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• pp.27-40
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• 2007

The streams evolve to diverse forms influenced by various factors such as rock resistance tectonic process, sediments and discharge. This study focuses on erosion resistance of rocks among these factors. The morphology of plane and longitudinal profile has been analysed in upper and lower reach of 6 streams using GIS; Yeoryong-cheon, Heungjeong-cheon, Duhak-cheon, Daehwa-cheon, Namcheon-cheon, Guryong-cheon, having distinct bedrock types between upper and lower reach. While the basins of granite have gentle slope, low concavity and wide valley area, those of gneiss form steep slope, high concavity and narrow valley area. However, the basins of sedimentary rock make steep slope and high relief in main channel, the other features show some differences in each stream. Among the various morphological features, the indices on slope and concavity of main channel, drainage density, ratio of valley area, average slope and average relief of the basin which have clear differences between rocks in upper and lower reach are calculated to interpret the erosion resistance of rocks in upper and lower reach. As a result, the upper reaches composed of gneiss have the highest erosion resistance, sedimentary rocks in upper and lower reaches show moderate resistance, and granite reaches generally have the lowest resistance except the upper reaches bordered by sedimentary rock.

• Journal of the Korean Geotechnical Society
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• v.30 no.12
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• pp.15-25
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• 2014

In this study, types of rock slope failure are analyzed by considering both joint characteristics investigated on previous landslide regions located at northern part of Mt. Jiri and geographic features of natural slopes deduced from GIS. The landslide prediction map was produced by superposing the frequency ratio layers for the six geographic features including elevation, slope aspect, slope angle, shaded relief, curvature and stream distance, and then the landslide risk map was deduced by combination of the prediction map and the damage map obtained by taking account of humanity factors such as roads and buildings in the study area. According to analysis on geographic features for previous landslide regions, the landslides occurred as following rate: 88% at 330~710 m in elevation, 77.7% at $90{\sim}270^{\circ}$ in slope aspect, 93.9% at $10{\sim}40^{\circ}$ in slope angle, 82.78% at grade3~7 in shaded relief, 86.28% at -5~+5 in curvature, and 82.92% within 400m in stream distance. Approximately 75% of the landslide regions belongs to the region of 'high' or 'very high' grade in the prediction map, and 13.27% of the study area is exposed to 'high risk' of landslide.

• Journal of the Korean Geotechnical Society
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• v.29 no.2
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• pp.35-45
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• 2013

The void ratio is an important parameter for reflecting the soil behavior including physical property, compressibility, and relative density. The void ratio can be obtained by laboratory test with extracted soil samples. However, the specimen has a possibility to be easily disturbed due to the stress relief when extracting, vibration during transportation, and error in experimental process. Thus, the theoretical equations have been suggested for obtaing the void ratio based on the elastic wave velocities. The objective of this paper is to verify the accuracy of the proposed analytical solution through the error norm. The paper covers the theoretical methods of Wood, Gassmann and Foti. The elastic wave velocity is determined by the Field Velocity Probe in the southern part of Korean Peninsular. And the rest parameters are assumed based on the reference values. The Gassmann method shows the high reliability on determining the void ratio. The error norm is also analyzed as substitution of every parameter. The results show every equation has various characteristics. Thus, this paper may be widely applied for obtaining the void ratio according to the field condition.

• Research in Community and Public Health Nursing
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• v.26 no.2
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• pp.100-107
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• 2015

Purpose: To explore the association between sleep and the risk of accidental injury at school among Korean adolescents. Methods: From the database of the Ninth Korea Youth Risk Behavior Web-based Survey (KYRBS), the researcher selected 63,307 adolescents who responded to a survey on sleep hours. We conducted logistic regression with sleep duration and fatigue after sleep as independent variables, the risk of injury at school as a dependent variable, and gender, grade, school type, economic status, parents' education level, number of participations in physical education, and current smoking and drinking as control variables. Results: Using 9 hours of sleep as the reference, the adjusted injury risk (odds ratio) was 1.74 for those sleeping less than 5 hours a day, 1.61 for 5 hours, 1.45 for 6 hours, 1.31 for 7 hours, 1.13 for 8 hours, and 1.40 for 10 hours or longer. The difference between each pair of groups was statistically significant. In this study, injury risk increased as sleep duration decreased and fatigue after sleep increased. Conclusion: The findings suggest that a short nightly duration of sleep and fatigue after sleep can be considered potential risk factorsfor unintentional injuries at school among Korean adolescents.

• Journal of the Korean GEO-environmental Society
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• v.7 no.4
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• pp.15-24
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• 2006

It is well known that earth pressure on the cylindrical open caisson and cylindrical retaining wall of a shaft is less than that at-rest and in plane strain condition because of the horizontal and vertical arching effects due to wall displacement and stress relief. In order to examine the earth pressure distribution of a cylindrical wall, model tests were performed in dry sand for the care of constant wall displacement with depth. Model test apparatus which can control wall displacement, wall friction, and wall shape ratio was developed. The effects of various factors that influence earth pressure acting on the cylindrical retaining wall of a shaft were investigated.

• Journal of Chest Surgery
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• v.17 no.4
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• pp.644-656
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• 1984

In Tetralogy of Fallot, the most common congenital cyanotic heart disease, the mortality is decreasing continuously with adequate type and timing of operation. At S.N.U.H., 195 patients were operated from January 1982 to December 1983 and 176 patients among them were analysed in the view of pre-operative pulmonary arterial condition measured by cardiac cineangiogram. The most common associated anomaly was PFO and ASD and they did not affect the postoperative course and mortality. The overall mortality rate was 8.5% in 1982 and 6.8% in 1983 but under 2 years of age, the mortality rate was relatively high as 25% in 1982 and 16.7% in 1983, and when transannular patch widening of Right Ventricular Outflow Tract was used, the mortality rate was 12.5% in 1982 and 27.3% in 1983. Preoperative angiographic measurements of the pulmonary arterial status for prediction of the ratio between the Left Ventricular and Right Ventricular peak systolic pressure were calculated retrospectively according to the Blackstones formula, and the predicted value of PRV/LV greater than 0.6 carried apparently high complication and mortality rate as 16.6% M.R. in 1982 and 11.1 % in 1983. Among postoperative complications, c-RBBB occurred most frequently about 50% but did not influenced to mortality, Low Cardiac Output Syndrome was developed in about 40%. If we select the patient who should have the staged operation including shunt operation and choose the type of RVOT relief, we expect the improvement of postoperative clinical results.

• Journal of Chest Surgery
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• v.20 no.2
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• pp.261-269
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• 1987

From 1976 through 1986, authors have experienced 127 cases of peripheral vascular surgery which had been done in this department. There were 29 cases of atherosclerosis obliterances including 7 Leriche syndrome, 32 Buerger`s diseases, 25 arterial thromboembolisms, 21 vascular injuries, 2 peripheral arterial aneurysms, 2 renovascular hypertensions, 1 congenital A-V malformation, 13 varicose vein of lower extremities, and 2 Jugular venous ectasia. Cases with vena caval disease and aortic disease were excluded. The mean age of ASO and Buerger`s disease was 56.1 yrs, 33.8 yrs respectively. The male to female ratio showed marked male preponderance [27:2, and 30:2], and almost every male patient was smoker. The indication of operation was similar in both disease entities. The method of operation for ASO were bypass procedure [17], thromboendarterectomy [6], and lumbar sympathectomy [5], and for Buerger`s disease were mainly sympathectomy and few bypass procedures and amputations. Seventeen patients with ASO were followed from 3 to 75 month and overall patency rate for bypass or endarterectomy in one and two months and 2 1/2 yr were 93%, 87%, and 31% respectively. Post operatively patient`s symptoms was relieved or alleviated in almost ASO patients, and about 60% of Buerger`s disease. We concluded that in patient with ischemic limb, we must revascularized aggressively for symptomatic relief. And choice of graft for bypass procedure was to be evaluated further.

• Journal of Broadcast Engineering
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• v.11 no.4 s.33
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• pp.448-457
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• 2006

HRTF DB, including the information of the sounds which is arrived to our ears, is generally used to make a 3D sound. But it can decline some three-dimensional effects by the confusion between front and back directions due to the non-individual HRTF depending on each listener. In this paper, we propose a new method to use psychoacoustic theory that reduces the confusion of sound image localization. And we make use of an excitation energy by the sense of hearing. This method is brought HRTF spectrum characteristics into relief to draw out the energy ratio about the bark band. Informal listening tests show that the proposed method improves the front-back sound localization characteristics much better than the conventional methods.