• 한국태양에너지학회 논문집
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• 제37권6호
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• pp.69-77
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• 2017

The amount of solar irradiation obtained by a photovoltaic (PV) solar panel is the major factor determining the power generated by a PV system, and the array tilt angle is critical for maximizing panel radiation acquisition. There are three types of PV systems based on the manner of setting the array tilt angle: fixed, semi-fixed, and tracking systems. A fixed system cannot respond to seasonal solar altitude angle changes, and therefore cannot absorb the maximum available solar radiation. The tracking system continually adjusts the tilt angle to absorb the maximum available radiation, but requires additional cost for equipment, installation, operation, and maintenance. The semi-fixed system is only adjusted periodically (usually seasonally) to obtain more energy than a fixed system at an overall cost that is less than a tracking system. To maximize semi-fixed system efficiency, determining the optimal tilt angle adjustment schedule are required. In this research, we conducted a simulation to derive an optimal operation schedule for a semi-fixed system in Seoul, Korea (latitude $37.5^{\circ}$). We implemented a solar radiation acquisition model and PV genereation model on MATLAB. The optimal operation schedule was derived by changing the number of tilt angle adjustments throughout a year using a Dynamic Algorithm. The results show that adjusting the tilt angle 4 times a year was the most appropriate. and then, generation amount of PV system increased 2.80% compared with the fixed system. This corresponds to 99% compared to daily adjustment model. This increase would be quite valid as the PV system installation area increased.

• 한국농공학회논문집
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• 제53권1호
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• pp.17-28
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• 2011

This study was performed to ascertain the possibility of securing inflows to reservoir with low ratio of watershed to paddy field areas by outside diversion weir. The case of Maengdong reservoir and Samryong diversion weir was selected. Most of inflows to Maengdong reservoir with watershed area of $7.06\;km^2$ and total storage capacity of $1,269{\times}10^4\;m^3$ are filled with intake water from outside Samryong diversion weir. Only using water storage data in Maengdong reservoir from 1991 to 2009, the range of water intake in Samryong diversion weir to Maengdong reservoir was optimized to 0.135~30 mm/d, from which water intake to Maengdong reservoir was $1,672.9{\times}10^4\;m^3$ (70.1 %) and downstream outflow to Weonnam reservoir was $714.4{\times}10^4\;m^3$ (29.9 %). The parameters of DAWAST model for reservoir inflow were determined to UMAX of 313.8 mm, LMAX 20.3 mm, FC 136.8 mm, CP 0.018, and CE 0.007. Inflows to Maengdong reservoir were $427.1{\times}10^4\;m^3$ (20.3 %) from inside watershed, and $1,672.9{\times}10^4\;m^3$ (79.7 %) from outside. Paddy irrigation water requirements were estimated to $1,549{\times}10^4\;m^3$ on annual average. Operation rule curve was drawn by using daily inflow and irrigation requirement data. By securing the amount of inflow to Maengdong reservoir to about 80 % from outside Samryong diversion weir, water supply capacity for irrigation of $1,549{\times}10^4\;m^3/yr$ was analyzed to be enough. Additional water supplies for instream flow were analyzed to $1,412\;m^3/d$ in normal reservoir operation, $36,000\;m^3/d$ in withdrawal limit operation by operation rule curve from October to March of non irrigation period.

• 전기학회논문지
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• 제65권7호
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• pp.1151-1160
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• 2016

In recent years, the energy storage systems such as LiB, NaS, RFB(Redox-Flow Battery), Super- capacitor, pumped hydro storage, flywheel, CAES(Compressed Air Energy Storage) and so on have received great attention as practical solutions for the power supply problems. They can be used for various purpose of peak shaving, load leveling and frequency regulation, according to the characteristics of each ESS(energy storage system). This paper will focus at 1 MWh RFB system, which is being developed through the original technology project of energy material. The output of ESS is mainly characterized by C-rate, which means that the total rated capacity of battery will be delivered in 1 hour. And it is a very important factor in the ESS operation scheduling. There can be several options according to the operation intervals 15, 30 and 60minutes. The operation scheduling is based on the optimization to minimize the daily electricity cost. This paper analyzes the cost-saving effects by the each operating time-interval in case that the RFB ESS is optimally scheduled for peak shaving and load leveling.

• 한국농공학회논문집
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• 제63권4호
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• pp.97-104
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• 2021

Despite the practical limitations of calculating the amount of inflow and supply related to the operation of agricultural reservoirs, the role of agricultural reservoirs is gradually being emphasized. In particular, as interest in disaster safety has increased, the demand for preliminary measures to prepare for disasters has been rising, for instance, pre-discharging agricultural reservoirs for flood control. The aim of this study is to analyze the plans for the flood season reservoir operation considering pre-discharge period and water level limit. Accordingly, we optimized the simulation of daily storage using the ratio correction factor (RCFs) and analyzed the amount of inflow and supply using K-HAS. In addition we developed the drought determination coefficient (k) as a indicator of water availability and applied it for supplementing the risk level criteria in the Drought Crisis Response Manual. The results showed that it would be difficult to set the water level limit during the flood period in the situation of little water supply for flood control in agricultural reservoirs. Therefore, it is necessary to operate the reservoir management regulations after measures such as securing additional storage water are established in the future.

• 한국화재소방학회논문지
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• 제32권4호
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• pp.110-121
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• 2018

본 논문은 소방용 화학보호복 착용 현장대원의 일상 훈련용 프로토콜 설계 및 활동성 분석에 관한 연구이다. 화학사고 및 화학테러 현장에 최초 투입되는 소방대원들의 대처능력 향상 및 안전성 확보를 위해 총 10단계의 일상 훈련용 프로토콜을 설계하였다. 설계된 프로토콜은 크게 소방용 화학보호복 일상 적응을 위한 광범위 활동 프로토콜(1, 2, 6, 7, 9단계)과 손을 활용한 정밀작업 프로토콜(3, 4, 5단계) 그리고 강한 신체적 부담을 요구하는 프로토콜(8, 10단계)로 구성하였다. 프로토콜에 따른 활동성 측정결과 소방용 화학보호복 착용 시가 미착용 시보다 평균최대심박수는 1단계 20.32%, 2단계 18.69%, 3단계 25.23%, 4단계 34.77%, 5단계 27.44%, 6단계 30.24%, 7단계 25.33%, 8단계 22.25%, 9단계 22.80%, 10단계 20.85% 증가되는 것으로 나타났다. 평균최대호흡수는 1단계 및 2단계를 제외하고 3단계 1.92%, 4단계 4.11%, 5단계 1.24%, 6단계 3.95%, 7단계 0.93%, 8단계 10.23%, 9단계 3.36%, 10단계 15.10% 증가되는 것으로 나타났다.

• 동서간호학연구지
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• 제11권1호
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• pp.33-41
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• 2005

This study was conducted to identify the effect of meridian acupressure on defecation of patients with post spinal operation. The nonequivalent control group posttest only design was used. The data were obtained from 77 post spinal operative patients, 34 in the experimental 43 in control group in Y Hospital, Seoul, Korea. The neurosurgical unit A and B ward, assigned by matched sample by the name of operation such as laminectomy and posterior lumbar interbody fusion are performed. Meridian acupressure meant the method that an examiner presses response points distributed in the pass of energy vessel. In this study, meridian acupressure program was performed on as points in order of Hegue (LI-4), Zhigou (TE-6), Zusanli (S-36), Shangjuxu (S-37), Xiajuxu (S-39), Tianshu (S-25), Taichong (L-3) which was known to be related to large intestine. Data were collected from 1, July 2003 to 1, September 2003. Meridian acupressure program was carried out for 20 minutes 4 hours after operation twice daily. In order to evaluate the effect of meridian acupressure intervention, they were asked time of bowel recovery, gas passing, and defecation though questionnaire method. Data were analyzed by the SPSS/ WIN 11.0 program. The results of this study were summarized as follows; 1. Homogeneity tests of general characteristics and operation related characteristics of the experimental group and the control group were performed. General characteristics included age, sex, defecation habit, eating pattern, fluid intake, life style, activity, usage of laxative and etc. 2. Hypotheses were verification as follows; 1) Recovery of bowel sound of the experimental group who received meridian acupressure intervention was faster than that of the control group after spinal operation (t=-6.770,P=.000). 2) Time of gas passing of the experimental group who received meridian acupressure program was faster than that of the control group after spinal operation (t=-8.003, P=.000). 3) Time to defecation of the experimental group who received meridian acupressure program was faster than that of the control group after spinal operation (t=-9.026, P=.000). 4) Abdominal discomfort due to defecation of the experimental group who received meridian acupressure program was lesser than that of the control group after spinal operation (t=-3.431, P=.001). From these results, meridian acupressure intervention was effective for recovery of bowel sound, reduce time to gas passing, time to defecation and lessen abdominal discomfort due to defecation on post spinal operative patients. And therefore this intervention can probably considered on clinical practice.

• 한국지리정보학회지
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• 제11권1호
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• pp.20-30
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• 2008

본 연구에서는 SWAT 모형을 이용하여 유역내 농업용 저수지의 운영이 유역 출구인 하천 지점에서의 유출에 미치는 영향을 분석하고자 하였다. 안성천 유역 공도수위관측소의 상류 유역을 대상으로, 유역내 고삼과 금광 농업용 저수지의 방류량 고려시와 미고려시에 대한 공도지점에서의 각각의 하천유출 거동을 분석하였다. SWAT 모형에서 저수지 물수지 분석모듈을 수정하여, 저수지의 일별 관측 저수위로부터 계산된 저수량과 수표면적을 이용하여 저수지의 일 방류량 자료를 생성하였다. 이를 이용하여 공도수위관측소의 5개년(1997~2001) 동안의 일별 하천 유출량 자료를 대상으로 모형의 보정(1997, 1998, 1999년)과 검증(2000, 2001년)을 실시하였다. 검증기간에 대한 Nash-Sutcliffe 모델효율은 0.55, RMSE는 2.33 mm/day로 나타났다. 한편, 두 저수지의 방류량을 고려하지 않은 상태에서의 모의결과는 한 결과, Nash-Sutcliffe 모델효율은 0.37로, RMSE는2.91 mm/day로 나타나 저수지 고려시의 결과와 비교하면 각각 0.18의 모델효율 저하, 0.58%의 오차증가를 보였다. 따라서 농업용 저수지가 있는 유역에서는 SWAT 모형의 활용시, 저수지 유역에서의 저수지에 의한 저류효과 및 방류 영향을 고려하여야 하는 것으로 나타났다.

• Journal of Korean Biological Nursing Science
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• 제4권2호
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• pp.19-40
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• 2002

The purpose of this study was to determine the effect of DHEA on Type I(soleus) and II muscles(plantaris, gastrocnemius) in a focal brain ischemia model rat. Thirty-seven male Sprague-Dawley rats with $200{\sim}250g$ body weights were randomly divided into four groups : CINS(cerebral ischemia + normal saline), CIDH(cerebral ischemia + DHEA), SHNS(sham + normal saline), SHDH (sham + DHEA). Both the CINS and CIDH groups were undergone a transient right middle cerebral artery occlusion operation. In the SHNS and SHDH groups, a sham operation was done. DHEA was administered daily at a dose of 0.34mmol/kg, and normal saline was administered daily at the same dose by intraperitoneal injection for 7days after operation. Cerebral infarction in the CINS and CIDH groups was identified by staining with 2% triphenyltetrazolium chloride solution for 60 minutes. The data were analyzed by Kruskal-Wallis test and Mann-Whitney U test using the SPSSWIN 9.0 program. The results were summarized as follows: 1) The muscle weights of soleus(Type I), plantaris and gastrocnemius(Type II) in CINS group were significantly less than those of the SHNS group(p<.01). The muscle fiber cross-sectional area of the CINS group was significantly less than that of the SHNS group in Type I muscle fiber of the soleus and Type II muscle fiber of the plantaris and gastrocnemius(p<.05). The myofibrillar protein content of the CINS group was significantly less than that of the SHNS group in the left gastrocnemius and right soleus(p<.05). 2) The muscle weights of the soleus, plantaris and gastrocnemius except the unaffected side of the plantaris in the CIDH significantly increased compared to those of the CINS group(p<.05). The muscle fiber cross-sectional area of the CIDH group significantly increased compared to that of the CINS group in Type II muscle fiber of the plantaris and gastrocnemius(p<.05). The myofibrillar protein content of the CIDH group significantly increased compared to that of the CINS group in the left soleus(p<.05). 3) On the post-op 8 day, the body weight of the CINS group was significantly less than that of the CIDH, SHNS and SHDH groups(p<.01). Total diet intake of the CINS and CIDH groups was significantly less than that of the SHNS and SHDH groups(p<.01). Based on these results, it was identified that muscle atrophy could be induced during the 7 days after cerebral infarction, and DHEA administration during the early stage of cerebral infarction might attenuate muscle atrophy.

• 대한교통학회지
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• 제23권2호
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• pp.75-82
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• 2005

2004년 4월에 개통한 고속철도는 철도수송시장 뿐만 아니라 지역간 교통수단의 변화 등 국가 전체적으로 적지않은 변화를 나타내고 있다. 본 연구에서는 예측수요와 실제치간의 차이를 파악하고, 실제 이용치에 대한 경부축 중심의 지역간 교통수단분담률과, 경부축 주요 구간(경부축 주요 4개 구간 대상: 서울권~천안권, 대전권, 대구권, 부산권)의 철도역간 수송수요를 중심으로 하여 지역간 교통수단 및 철도차종별 수용의 변화를 살펴보고자 한다. 경부축의 지역간 교통수단의 분담률 변화는 고속철도 개통전과 개통후의 지역간 이용수요를 분석하여 비교하고, 다음으로 KTX 개통 이후 철도시장내에서의 열차 차종별 분담률을 비교함으로써 차종별 열차 선호도와 이용수용의 분담률을 분석하고자 한다. 결과적으로 지역간 여객수송에서 철도의 역할이 크게 증대되었으며, 향후에도 지속적으로 그 영향력은 커질 것으로 전망된다. 또한 지역간 여객수송에서 항공이 독점하고 있던 장거리 고급수단으로서의 이미지가 철도로 확대되고, 도로부분은 지역간 단거리 여객수송 시장에서 입지가 좁아지고 있다는 사실이다. 수송효율적인 철도수소의 증대는 전체 교통시장의 관점에서도 바람직한 현상이며, 점진적으로 고급수단인 KTX와 새마을호 및 무궁화호를 통합한 일반철도 이원화체계가 운영자 입장이나 이용자 입장에서 바람직할 것으로 판단된다.

• 한국대기환경학회지
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• 제31권5호
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• pp.461-471
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• 2015

Base on emission factors derived from National Institute of Environmental Research, Particulate matter from combined cycle power plants (CCPPs) has been estimated to be a important source of $PM_{10}$. Generally there is no serious emission of particulate matter in CCPPs. because the fuel of them is natural gas. But emission gas after long shut down season has very high dust content. Therefore $PM_{10}$ emission rate is dependent on its operation mode. In this study, particulate dispersion study for new city near CCPPs complex has performed using CALPUFF model for three case. $PM_{10}$ concentration has big difference between normal operation and 2 case start-up condition after long shutdown. In normal operating conditions, daily $0.32{\sim}0.50{\mu}g/m^3$ influence on of the surrounding area. But when 1~2 aerobic high concentration discharged conditions, average concentration is higher about $9.2{\sim}34.1{\mu}g/m^3$ than normal operating conditions.