• KSCE Journal of Civil and Environmental Engineering Research
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• v.40 no.6
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• pp.603-611
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• 2020

This study collected and analyzed transportation card data in order to better understand the operation and usage of city buses in Ulsan Metropolitan City in Korea. The analysis used quantitative and qualitative indicators according to the characteristics of the data, and also the categories were classified as general status, operational status, and satisfaction. The existing city bus survey method has limitations in terms of survey scale and in the survey process itself, which incurs various types of errors as well as requiring a lot of time and money to conduct. In particular, the bus means indicators calculated using transportation card data were analyzed to compensate for the shortcomings of the existing operational status survey methods that rely entirely on site surveys. The city bus index calculated by using the transportation card data involves quantitative operation status data related to the user, and this results in the advantage of being able to conduct a complete survey without any data loss in the data collection process. We took the transportation card data from the entire city bus network of Ulsan Metropolitan City on Wednesday April 3, 2019. The data included information about passenger numbers/types, bus types, bus stops, branches, bus operators, transfer information, and so on. From the data analysis, it was found that a total of 234,477 people used the city bus on the one day, of whom 88.6% were adults and 11.4% were students. In addition, the stop with the most passengers boarding and alighting was Industrial Tower (10,861 people), A total of 20,909 passengers got on and off during the peak evening period of 5 PM to 7 PM, and 13,903 passengers got on and off the No. 401 bus route. In addition, the top 26 routes in terms of the highest number of passengers occupied 50% of the total passengers, and the top five bus companies carried more than 70% of passengers, while 62.46% of the total routes carried less than 500 passengers per day. Overall, it can be said that this study has great significance in that it confirmed the possibility of replacing the existing survey method by analyzing city bus use by using transportation card data for Ulsan Metropolitan City. However, due to limitations in the collection of available data, analysis was performed only on one matched data, attempts to analyze time series data were not made, and the scope of analysis was limited because of not considering a methodology for efficiently analyzing large amounts of real-time data.

• Korean Journal of Soil Science and Fertilizer
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• v.43 no.3
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• pp.374-383
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• 2010

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a ground-based polarimetric scatterometer has advantages of monitoring crop conditions continuously with full polarization and different frequencies. Kim et al. (2009) have measured backscattering coefficients of paddy rice using L-, C-, X-band scatterometer system with full polarization and various angles during the rice growth period and have revealed the necessity of near-continuous automatic measurement to eliminate the difficulties, inaccuracy and sparseness of data acquisitions arising from manual operation of the system. In this study, we constructed an X-band automatic scatterometer system, analyzed scattering characteristics of paddy rice from X-band scatterometer data and estimated rice growth parameter using backscattering coefficients in X-band. The system was installed inside a shelter in an experimental paddy field at the National Academy of Agricultural Science (NAAS) before rice transplanting. The scatterometer system consists of X-band antennas, HP8720D vector network analyzer, RF cables and personal computer that controls frequency, polarization and data storage. This system using automatically measures fully-polarimetric backscattering coefficients of rice crop every 10 minutes. The backscattering coefficients were calculated from the measured data at a fixed incidence angle of $45^{\circ}$ and with full polarization (HH, VV, HV, VH) by applying the radar equation and compared with rice growth data such as plant height, stem number, fresh dry weight and Leaf Area Index (LAI) that were collected at the same time of each rice growth parameter. We examined the temporal behaviour of the backscattering coefficients of the rice crop at X-band during rice growth period. The HH-, VV-polarization backscattering coefficients steadily increased toward panicle initiation stage, thereafter decreased and again increased in early-September. We analyzed the relationships between backscattering coefficients in X-band and plant parameters and predicted the rice growth parameters using backscattering coefficients. It was confirmed that X-band is sensitive to grain maturity at near harvesting season.

• Advances in pediatric surgery
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• v.4 no.2
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• pp.149-155
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• 1998

Thirty three members of the Korean Association of Pediatric Surgeons were surveyed to determine the clinical manifestations and current management of infantile hypertrophic pyloric stenosis (IHPS). The members completed a registration form and a questionnaire that indicated their treatment preferences for patients treated during 1996. The response rate was 84.8 %, and 23 institutions participated. Three hundred and sixty-three cases of IHPS were analysed. The male to female ratio was 5.15: 1. The presenting symptoms were nonbilious vomiting in 363 cases(100 %), palpable mass in the upper abdomen in 200 cases (55.1 %) and visible peristaltic waves in 67 cases(18.5 %). Fluid therapy was done in 161 cases(44.4 %) for preoperative preparation. Twenty patients(5.5 %) were premature. There were 27 low birth weight babies(7.7 %). The onset of symptoms ranged from 1 to 14 weeks of age with a peak occurrence at 2 to 4 weeks of age. Two hundred and thirty-six cases(66.6 %) presented within 4 weeks of age. There was one set of male twins and a family history of twins. The modes of feedings were: breast feeding; 69 cases(24.5 %), formula feeding; 176 cases(62.4 %) and mixed feeding; 37 cases(13.1 %). The preferred diagnostic modalities were ultrasonography (US) 229 cases(63.1 %), UGI series 27 cases(7.4%) and US and UGI series combined 86 cases(23.7 %). Only 21 cases(5.8 %) were operated on without imaging study, ie. with positive physical finding. Perforation of the mucosa during pyloromytomy occurred in 5 cases. All were treated successfully with primary closure. Persistent vomiting over 2 weeks after operation were reported in 5 cases. Three wound infections, one aspiration pneumonia and one postoperative bleeding were reported. There was no mortality in 363 cases.

• Journal of Korea Water Resources Association
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• v.45 no.3
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• pp.301-316
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• 2012

Two models, TANK and SWAT (Soil and Water Assessment Tool) were compared for simulating natural flows in the Paldang Dam upstream areas of the Han River basin in order to understand the limitations of TANK and to review the applicability and capability of SWAT. For comparison, simulation results from the previous research work were used. In the results for the calibrated watersheds (Chungju Dam and Soyanggang Dam), two models provided promising results for forecasting of daily flows with the Nash-Sutcliffe model efficiency of around 0.8. TANK simulated observations during some peak flood seasons better than SWAT, while it showed poor results during dry seasons, especially its simulations did not fall down under a certain value. It can be explained that TANK was calibrated for relatively larger flows than smaller ones. SWAT results showed a relatively good agreement with observed flows except some flood flows, and simulated inflows at the Paldang Dam considering discharges from upper dams coincided with observations with the model efficiency of around 0.9. This accounts for SWAT applicability with higher accuracy in predicting natural flows without dam operation or artificial water uses, and in assessing flow variations before and after dam development. Also, two model results were compared for other watersheds such as Pyeongchang-A, Dalcheon-B, Seomgang-B, Inbuk-A, Hangang-D, and Hongcheon-A to which calibrated TANK parameters were applied. The results were similar to the case of calibrated watersheds, that TANK simulated poor smaller flows except some flood flows and had same problem of keeping on over a certain value in dry seasons. This indicates that TANK application may have fatal uncertainties in estimating low flows used as an important index in water resources planning and management. Therefore, in order to reflect actually complex and complicated physical characteristics of Korean watersheds, and to manage efficiently water resources according to the land use and water use changes with urbanization or climate change in the future, it is necessary to utilize a physically based watershed model like SWAT rather than an existing conceptual lumped model like TANK.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.30 no.6
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• pp.465-473
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• 2004

Purpose : The essential triad for nerve regeneration is nerve conduit, supporting cell and neurotrophic factor. In order to improve the peripheral nerve regeneration, we used polyglycolic acid(PGA) tube and brain-derived neurotrophic factor(BDNF) gene transfected Schwann cells in sciatic nerve defects of SD rat. Materials and methods : Nerve conduits were made with PGA sheet and outer surface was coated with poly(lactic-co-glycolic acid) for mechanical strength and control the resorption rate. The diameter of conduit was 1.8mm and the length was 17mm Schwann cells were harvested from dorsal root ganglion(DRG) of SD rat aged 1 day. Schwann cells were cultured on the PGA sheet to test the biocompatibility adhesion of Schwann cell. Human BDNF gene was obtained from cDNA library and amplified using PCR. BDNF gene was inserted into E1 deleted region of adenovirus shuttle vector, pAACCMVpARS. BDNF-adenovirus was multiplied in 293 cells and purified. The BDNF-Adenovirus was then infected to the cultured Schwann cells. Left sciatic nerve of SD rat (250g weighing) was exposed and 14mm defects were made. After bridging the defect with PGA conduit, culture medium(MEM), Schwann cells or BDNF-Adenovirus infected Schwann cells were injected into the lumen of conduit, respectively. 12 weeks after operation, gait analysis for sciatic function index, electrophysiology and histomorphometry was performed. Results : Cultured Schwann cells were well adhered to PGA sheet. Sciatic index of BDNF transfected group was $-53.66{\pm}13.43$ which was the best among three groups. The threshold of compound action potential was between 800 to $1000{\mu}A$ in experimental groups which is about 10 times higher than normal sciatic nerve. Conduction velocity and peak voltage of action potential of BDNF group was the highest among experimental groups. The myelin thickness and axonal density of BDNF group was significantly greater than the other groups. Conclusion : BDNF gene transfected Schwann cells could regenerate the sciatic nerve gap(14mm) of rat successfully.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.65-76
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• 1982

This survey was conducted to investigate the status of repair and maintenance of 4 wheel tractor for a basic reference to the improvement of quality and proper utilization of tractors. Thirty two counties from eight provinces, except Jeju, were covered in this study in order to investigate annual break-down and repair of tractor in 1980. The analyzed results are summarized as follows; 1. The average number of break-down of large size tractors(47ps) was 5.0 times in a year and it was about twice of that of small size tractors(19-23ps). The break-down frequency per 100 hours of use was 1.11 times in the large size and 0.65 times in the small size tractors. 2. 75.6 percent of total break-down was occured in main body of tractor and 24.4 percent in attachments. In particular, the break-down of plow and rotavator was more than 80 percent of total break-down of the small size tractor attachments. 3. The large size tractors which were occured more than one times of break-down a year was 75 percent and its rate of the small size tractor was 62 percent. But 9 percent of tractor surveyed had more than ten times of break-down in a year 4. The frequency of break-down had a peak in May, and it was directly proportional to the hours of use. 5. The causes of break-down were poor maintenance and operation by 29.8 precent, old parts by 30.2 percent, poor quality of parts by 20.6 percent, poor field condition by 16.3 percent and others by 3.1 percent. 6. Annual number of repair was 5.5 times and among them 55.6 percent was done by shop and 44.4 percent by operator. 7. Total required repair time was 30.6 hours a year in the large size tractor and 19.9 hours in the small size tractor. Average repair time was 3.62 hours a time. 8. Annual repair cost was 278 thousand won in the large size tractor and 70 thousand won in the small size tractor. The repair cost per hour of use was 621 won in the large size and 198 won in the small size tractor. 9. The repair cost rate of tractor(Y) was regulated with tractor age (X) as follow; Y=0.752X In case of the service life of tractor was 10 years, the total repair cost rate was 64 percent.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.3 no.2
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• pp.160-168
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• 2000

Purpose: The purpose of this study was to evaluate the clinical and abdominal ultrasonogra- phic(US) features of spontaneously reduced transient small bowel intussusception in chlidren. Methods: We retrospectively reviewed the clinical and US findings of 98 children with intussusception who were admitted to the Pediatric Department of Ulsan Dong-Kang General Hospital from Mar. 1999 to Feb. 2000. Results: 1) Among 98 cases, there were 12 cases (12.3%) of transient small bowel intussusception(TSBI) and 86 cases (87.7%) of classic intussusception (CI). 2) The peak incidence of age in TSBI was over 3 years, which was older than that in CI. With regard to sex distribution, male predominated in both type. 3) Clinical symptoms and signs including cyclic irritability, vomiting, bloody stool, and abdominal mass in TSBI group were less common than those in CI group (41.7%, 33.4%, 0.0%, 0.0% vs 91.9%, 59.3%, 41.9%, 26.7%, respectively) but persistent abdominal pain was more common in TSBI group than in CI group (58.5% vs 11.2%). 4) The size of total target sign and surrounding peripheral hypoechoic rim of TSBI group on US were smaller than those of CI group ($11.95{\pm}2.61$ mm, $2.08{\pm}1.15$ mm vs $26.91{\pm}5.98$ mm, $7.86{\pm}2.77$ mm, respectively). 5) Concomittant illness was found more frequently in TSBI group than in CI group (66.7% vs 26.7%). 6) All case of TSBI group were reduced spontaneouly, which were confirmed by US, but none of CI group. Conclusion: Transient small bowel intussusception is probably more common than generally thought and its clinical and US findings is quite different from classical obstructing intussus-ception. Because all of our cases resulted in spontaneous reduction, we recommend careful observation and repeat examination rather than an immediate operation in transient small bowel intussusception.

• Journal of Chest Surgery
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• v.31 no.7
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• pp.679-683
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• 1998

From June 1995 to May 1997, we have implanted 52 Sorin Bicarbon mechanical valves in 41 patients. They were 16 men and 25 women, and their mean age was 47.4${\pm}$14.8(range; 18∼74 y.o.). 35(27 mm∼31 mm) were in mitral position, 15(19 mm∼25 mm) in aortic position, and 2(31 mm) in tricuspid position. 3 CABGs and a tumor excision were taken concomittantly. 35 patients were primary operation, and 6 were re-do operations. By intraoperative transesophageal doppler echocardiography, transvalvular peak/mean pressure gradient was 6.1${\pm}$2.7/2.4${\pm}$1.4 mmHg in mitral position and 27.6/10.7 mmHg in aortic position. The effective valve opening area in mitral position was 3.2${\pm}$0.6 cm2. Follow-up was total 508.6 patient-months, and mean follw-up was 12.7${\pm}$9.2 months. NYHA class was improved from 2.6${\pm}$0.6 to 1.2${\pm}$0.3 in average postoperatively. During that period, there was no operative death. 2 late non-valve related deaths were occurred. One was died of COPD, and the other was possible acute myocardial infarction. Among 7 postoperative complications, one valve related complication(minimal paravalvular leakage) was noticed. In conclusion, Sorin Bicarbon mechanical valve is believed one of the safe choice in clinical settings. It showed excellent hemodynamic and mechanical functions, and very low postoperative valve related complications in short term clinical experience.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.8
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• pp.880-886
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• 2007

We have proposed a new "hybrid" envelope elimination and restoration(EER) transmitter architecture using an efficiency optimized power amplifier(PA) and modified bias modulator. The efficiency of the PA at the average drain voltage is very important for the overall transmitter efficiency because the PA operates mostly at the average power region of the modulation signal. Accordingly, the efficiency of the PA has been optimized at the region. Besides, the bias modulator has been accompanied with the emitter follower for the minimization of memory effect. A saturation amplifier, class $F^{-1}$ is built using a 5-W PEP LDMOSFET for forward-link single-carrier wideband code-division multiple-access(WCDMA) at 1-GHz. For the interlock experiment, the bias modulator has been built with the efficiency of 64.16% and peak output voltage of 31.8 V. The transmitter with the proposed PA and bias modulator has been achieved an efficiency of 44.19%, an improvement of 8.11%. Besides, the output power is enhanced to 32.33 dBm due to the class F operation and the PAE is 38.28% with ACLRs of -35.9 dBc at 5-MHz offset. These results show that the proposed architecture is a very good candidate for the linear and efficient high power transmitter.

• Journal of the Korea Organic Resources Recycling Association
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• v.20 no.4
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• pp.106-117
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• 2012

Indirected heating dryer is used as one of the food waste treatment technologies for the production of the drier material supplied to the recycling facilities or end user. This study investigated the effect on drying efficiency for the operation of rotating screw with the circulating and falling movements on indirected drying process of food waste. The screw operating condition showed higher drying efficiency despite of the shorter drying time compared to the screw non-operating condition. The moisture content decreased to 14.4% from the initial moisture content of 77.1% after drying 5 hours in the screw operating condition. On the other hand, in the screw non-operating condition, the moisture content decreased slightly to 35.6% after drying 16 hours. During the drying process, variations of the water evaporation rate and particle size showed different tendencies depending on the moisture content regions. In the higher moisture content region above the glue zone(moisture content of about 50%-60%), the particle size increased and the water evaporation rate reached the highest peak. In the range of glue zone, the particle size maximized while the water evaporation rate decreased sharply. In the lower moisture content region below the glue zone, the water evaporation rate and particle size both decreased at the same time. The particle size distribution was widely ranged from 25.0mm to 0.25mm in the screw operating condition while it was narrowly distributed in the screw non-operating condition from 25.0mm to 3.56mm, especially highly concentrated to 25.0mm. It was regarded that the hygroscopic, capillary and gravitational water evaporated more easily from the intra-particle during the circulating and falling movement caused by the rotating of the screw and the difference of the cohesional force of water within intra-particle depending on the moisture content regions. Comparing the effect of the circulating and falling movement on drying efficiency, the water evaporation rates per time and per weight of dry solid in the screw operating condition were higher about 364% and 356%, respectively, than those of the screw non-operating condition.