• Journal of Wetlands Research
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• v.11 no.2
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• pp.67-76
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• 2009

The contribution of pollutant loadings from non-point source (NPS) to the four major rivers in Korea exceeded 22~37 % of the total loadings in 2004 and is expected to reach 60 % in 2020. Most of NPS loadings are coming from urban areas, especially from paved areas. Because of high imperviousness rate, many types of NPS pollutant are accumulating on the surface during dry periods. The accumulated pollutants are wash-off during a storm and highly degrading the water quality of receiving water bodies. For this reason, the Korean Ministry of Environment (MOE) developed the Total Maximum Daily Load (TMDL) program to protect the water quality by managing the point source and NPS loadings. NPS has high uncertainties during a storm because of the characteristics of rainfall and watershed areas. The rainfall characteristics can affect on event mean concentrations (EMCs), mass loadings, flow rate, etc. Therefore, this research was performed to determine EMCs for rainfall ranges from transportation landuses such as road and parking lot. Two sites were monitored over 45 storm events during the 2006/06 through 2008/10 storm seasons. Mean TSS EMCs decrease as rainfall ranges increase and highest at less than 10mm rainfall. The results of this study can be used to determine the efficient scale of BMP facility considering specific rainfall range.

• Journal of Chest Surgery
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• v.43 no.6
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• pp.627-634
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• 2010

Background: The durability of the tissue valve is important in choice between a mechanical valve and a tissue valve in cardiac surgery. We studied the mid-term results of tissue valve in the aortic position. Material and Method: The subjects were 380 patients who had undergone aortic prosthesis replacement between May 1990 and March 2009. We retrospectively analyzed hospital and outpatient records: the mean age was $69{\pm}9$ years; the male to female ratio was 227 : 162; and the mean follow-up duration was $46.7{\pm}40.8$ months (range 0~196 months). Result: 389 surgical cases in total had been taken with 380 patients. Early death occurred in 15 patients (3.9%). Overall survival rate at 1, 5 and 10 years were 92.3%, 78.1% and 54.2% respectively. Freedom from reoperation at 1, 5 and 10 years were 98.4%, 97.1% and 91.7% respectively. Freedom from structural valvular deterioration at 1, 5 and 10 years were 96.1%, 92.3% and 88.0% respectively. In the multivariate analysis of preoperative risk factors, young age (p<0.001) was significant risk factor for reoperation. High peak velocity in the postoperative period (p=0.034) and young age (p=0.029) were significant risk factors for structural valvular deterioration. Old age (p=0.001), long bypass time (p=0.035), concomitant coronary artery bypass graft surgery (p=0.003) and preoperative low left ventricular ejection fraction (p=0.003) were significant factors for early mortality. Preoperative estimated glomerular filtration rate (< 60 mL/min) (p=0.025) and persistent left ventricular hypertrophy (p=0.032) were the risk factors for late mortality. Conclusion: This study showed that the freedom from reoperation and the freedom from structural valvular deterioration in aortic tissue valve replacement were acceptable. It will be necessary to conduct further studies with long-term follow-up and more patients.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.119-119
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• 2010

무한 지속 가능한 지열 에너지를 활용한 공조시스템인 지열원 냉난방 시스템은 기존의 공조 시스템보다 열원이 안정적이기 때문에 높은 효율과 우수한 성능을 가지므로, 기후변화협약 대응의 주요수단으로서 기술개발과 보급이 증대되고 있다. 본 연구에서는 대수층 축열 지열원 열펌프 시스템에 대한 실증 연구를 통하여 대수층 축열 지열원 열펌프 시스템의 하절기 냉방 성능을 분석하였다. 대수층 축열 냉난방 시스템은 주입정과 양수정의 2개의 우물공이 설치되어 있으며, 겨울 난방 운전 중에 한 개의 우물공으로부터 지하수를 열펌프로 유입한 후 낮은 온도의 지하수를 타 우물공에 축열하고, 하절기에 겨울에 저온으로 축열된 우물공으로부터 지하수를 열펌프로 유입하여 온도가 증가된 지하수를 타 우물공에 주입한다. 즉, 계절별로 열펌프에서 생성된 냉수와 온수의 대수층 축열을 위하여 계절별로 주입정과 양수정이 바뀌게 된다. 본 연구의 대수층 축열 지열원 열펌프 시스템의 2009년 8월의 주요일자별 시스템 운전 중의 평균 냉방 열펌프 유닛 COP와 냉방 시스템 COP는 각각 4.7과 3.4이상의 우수한 성능을 나타냈다. 또한, 모든 일자에 대하여 외기온도가 $31.6^{\circ}C$서 $22^{\circ}C$까지 변화가 크게 나타났지만 열펌프 유닛 COP와 시스템 COP의 변화는 미소하였다. 이는 양수정으로부터의 지중 순환수가 운전기간 중에 $17.5^{\circ}C$로 일정하게 유지되었기 때문이다. 양수정과 주입정 사이에 5개의 관측공을 설치하였으며, 양수정 측에 인접한 관측공의 온도는 거의 변화가 없었으며, 단기간이지만 널리 사용되고 있는 수직밀폐형 시스템과 달리 지속적인 냉방운전 중의 양수 온도의 증가는 발생하지 않아 안정적인 성능을 나타냈다. 주입정에 인접한 모니터링 홀의 온도는 심도가 깊은 곳의 온도가 낮은 곳보다 높게 나타났다. 이는 냉방 운전 시 열펌프 유닛의 실외열교환기에서 지중 순환수가 냉매로부터 열을 취득하여 온도가 상승하면서 주입정측에 온열이 축열이 진행되었기 때문으로 분석되며, 하절기의 냉방 운전 시간이 증가할 경우 축열 효과는 더욱 증가할 것으로 예상된다. 양수정과 주입정 중간의 모니터링 홀의 온도는 2009년 8월 가동 중에 온도변화는 없었는데, 이는 양수정과 주입정 사이의 열간섭이 발생하지 않았기 때문으로 분석된다. 일자별로 운전 중의 열펌프 유닛 COP는 차이가 없었지만, 운전 및 정지 시간을 모두 포함한 시스템 소비전력과 냉방용량을 모두 합산하여 산정한 일일 평균 냉방 열펌프 유닛 COP와 냉방 시스템 COP는 일자별로 다소 차이가 발생하였는데, 이는 각 일자별로 열펌프 유닛 가동율의 차이로 인하여 열펌프 유닛 가동 전에 먼저 작동되는 지중순환펌프의 운전 소비전력의 차이와 열펌프의 단속운전 시의 열손실과 추거 소비전력의 차이 때문이다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.9
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• pp.3999-4008
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• 2012

This study investigated the symptoms of work-related musculoskeletal disorder(WMSDs) for physical therapists who have different work duties. We analyzed the symptoms in the musculoskeletal system and the degree of work-harmfulness by the survey of the symptom in the musculoskeletal system and rapid upper limb assessment(RULA) for pain control group(n=56), adult exercise group(n=53), and pediatric exercise group(n=22). As a result, 69.6% of the pain control group, 84.9% of the adult exercise group, 81.8% of the pediatric exercise group show the observable symptom. The adult exercise group has the biggest work load per hour in the final wrist & arm score of the ergonomic risk assessment using RULA. The action level of the pain control group is $3.0{\pm}0.9$; the Action Level of adult exercise group is $3.3{\pm}0.6$; the Action Level of the pediatric exercise group is $3.2{\pm}0.8$, and so it is shown that the adult exercise group has a problem of working posture. It is considered that devices and education system for preventing from WMSDs should come into wide use.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.12
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• pp.1287-1292
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• 2006

Constructed wetlands are well known as highly efficient system to treat wastewater from different sources. Among the constructed wetlands, upflow types of constructed wetlands have become a common selection of wastewater during the last decade. We conducted a pilot scale study at peen house on treating potential of nutrients by upflow vegetated filter(UVF) pilot wetland which was combined with hydrodynamic separator and used the cattail plant(Typha angustifolia), and operated with artificial nutrients influent. This study evaluate the performances of upflow vegetated fille, in removal of nutrients. The objectives of this study were two-fold: (i) to evaluate the nutrients removal performance of pilot-scale upflow vegetated filter, filled with a mixture of perlite and soil media and planted with cattails and (ii) to design of scale-up upflow vegetated filter using Froude number. Results indicated that, under the condition of the ranges of hydraulic surface load rate were $22.7{\pm}9.6\;m^3/m^2/day$, the average removal of $COD_{Mn}$, and TN, TP were 57.5%, 40.0% and 41.5%, respectively. Computational fluid dynamics, FLUENT 6.0 program was used to predict the distribution of velocity in UVF and hydrodynamic separator. Full scale UVF was designed using the Froude number scale-up method that was assumed geomertic similarity between model and prototype. Result shows that the UVF with 3 m diameter has capacity of design sewage flowrate 75 $m^3/day$.

• The KIPS Transactions:PartD
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• v.11D no.7 s.96
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• pp.1399-1408
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• 2004

Because there are so many spatio-temporal data in Moving Object Databases, a single disk system can not gain the fast response time and tota throughput. So it is needed to take a parallel processing system for the high effectiveness query process. In these existing parallel process-ing system. it does not consider characters of moving object data. Moving object data have to be thought about continuous report to the Moving Object Databases. So it is necessary think about the new Declustering System for the high performance system. In this paper, we propose the new Dechustering Policies of Moving objet data for high effectiveness query processing. At first, consider a spatial part of MBB(Minimum Bounding Box) then take a SD(SemiAllocation Disk) value. Second time, consider a SD value and time value which is node made at together as SDT-Proximity. And for more accuracy Declustering effect, consider a Load Balancing. Evaluation shows performance improvement of aver-age %15\%$ compare with Round-Robin method about $5\%\;and\;10\%$ query area. And performance improvement of average $6\%$ compare with Spatial Proximity method.

• Journal of Chest Surgery
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• v.29 no.3
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• pp.278-284
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• 1996

Nine infants with transposition of great arteries have undergone arterial switch operation from May 1989 to May 1994 in the Department of Thoracic and Cardiovascular Surgery, Yeungnam University Hospital. Patients' age ranged from 3 days to 90 days, averaging 30$\pm$21 days. Diagnosis was made by two-dimensional echocardiography in all patients. Eight patients were diagnosed as transposition of great arteries with ventricular septal defect and one patient was a simple transposition of great arteries. Associated anomalies were patent ductus arteriosus (8), atrial septal defect (7) and coarctation of aorta(1). The anatomy of the coronary arteries were 7 (77 %) type A and 2 (23 %) type D according to the Yacoub classification. Pulmonary artery reconstruction was done according to Lecompte maneuver with tautologous pericardial patch in 8 patients. Overall operative mortality rate was 55% Left heart failure and pulmonary hypertensive crisis were the cause of death on postoperative 1~2 days in three patients, and two succumbed to death due to sepsis on postoperative 2~ 3 weeks. The mean follow-up period was mean 17 months. No patient had clinically significant postoperative aortic regurgitation and supravalvular pulmonary stenosis. The excessive use of inotropic support postoperatively was identified as a stastically significant risk factor following the arterial switch operation. But other variables such as low body weight, long cardiopulmonary bypass time, excessive hemodilution during cardiopulmonary bypass, hypothermia and volume loading were not significant risk factors.

• Journal of Wetlands Research
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• v.16 no.2
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• pp.261-268
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• 2014

A sewage was treated using serially combined vertical(VFCW)and horizontal flow sand-filled reed constructed wetland(HFCW) with intermittent feeding. The sand had 1~3 mm diameter. The sewage entering the sewage treatment plant of Gyeonsang National University was fed into the reed constructed wetland bed for 10 minutes every 6 hours at the hydraulic load of $314L/m^2{\cdot}day$ based on the surface ares of the VFCW. In the VFCW effluent pH values were lower than those of the influent, whereas they were higher than those of the influent in the HFCW. DO values were increased in VFCW, but they were decreased in the HFCW. The OTR was $58.72gO_2/m^2{\cdot}day$ in the VFCW and $7.72gO_2/m^2{\cdot}day$ in the HFCW. Average removal efficiencies were SS 94.80%, BOD 90.77%, $COD_{Cr}$ 85.87%, $COD_{Mn}$ 87.72%, T-N 64.74%, $NH_4{^+}$-N 86.44%, T-P 87.70%. Nearly, half of T-N in the effluent was $NO_3{^-}$-N but the concentration of $NO_2{^-}$-N in the effluent was less than 0.64 mg/L.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.32 no.2
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• pp.180-185
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• 1999

Rotating Biological Contactor (RBC) was tested for the treatment of artificial rearing water in n simulated aquaculture system. Performance of RBC on the removal of TAN and COD was evaluated by controlling hydraulic residence time (HRT). As HRT of RBC was increased, TAN removal rate ana removal efficiency of RBC and TAN concentration of rearing water were increased, but COD removal rate was decreased. Total alkalinity consumption rate was increased by increasing HRT of RBC. Ratio between total alkalinity consumption rate and TAN removal rate was 7.73. HRT for maintaining lowest TAN and COD concentration of artificial rearing water was 14,6 minutes and at that condition TAN and COD concentration of the water was 1.28 and $5.59 g/m^3$, respectively.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.2
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• pp.3-8
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• 2009

The traction system has been mainly used for rehabilitation and correction of patients with spine or gait diseases in orthopedics or at home. Some problems could occur in human body when patients forced their training using the traction system. So it needs to measure a traction force and control the training time. However, most of products on market have no sensor measuring traction force. Thus we designed and made a sensor detecting traction force using strain gauge, amplifier for transition to output signal and experiment devices for performance test. We carried out experiment of a sensor detecting a traction force and measured electric responses of it with respect to traction loads. Maximum error was within about 1% for experiments in static condition and the average error was about 0.7% for experiments in dynamic condition. We concluded that it is possible to use the developed sensor for measurement of traction force since the maximum output variation of a sensor detecting a traction force was about 0.3% in $0^{\circ}C-60^{\circ}C$ temperature condition.