• The Journal of Engineering Geology
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• v.22 no.4
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• pp.387-398
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• 2012

Korean agricultural areas that employ water curtain cultivation (WCC) have recently suffered extensive groundwater shortages due to an increase in the number of facilities. The primary focus of this study is to measure the daily groundwater use and discharge rates in the Cheongweon and Chungju pilot areas, while the second focus is to estimate the total amount of groundwater used in WCC areas nationwide in Korea. Taking into consideration several factors, including motor type, outflow abilities of wells, records of daily minimum temperatures below $0^{\circ}C$, and the number of running wells according to weather variations, we estimated that $53,138m^3/ha$ of groundwater had been used in the 4-hectare Cheongweon pilot area during the winter period of late 2011 through early 2012. On a prorated areal basis, we can calculate that the total groundwater used nationwide was 0.57 billion $m^3$ in WCC areas of $10,746m^2$. This value is equivalent to 33.7% of the total agricultural groundwater use (1.69 billion $m^3$) in Korea. During 9-22 February 2012, the daily water discharge rate in the 4-ha Cheongweon pilot area ranged from 2,079 to $2,628m^3$, averaging $2,341m^3$. Combining this value with meteorological records for 94 days with a daily minimum temperature below $0^{\circ}C$ results in an estimated groundwater volume of $54,990m^3/ha$ for the pilot area during the 2011-2012 winter period. The total amount of groundwater used nationwide in WCC areas would then be 0.59 billion $m^3$, equivalent to 34.9% of the total agricultural groundwater use in Korea. In the Chungju area, the groundwater discharge rate was estimated to be less than 805 $m^3$/ha. This value, combined with weather data for 108 days with a daily minimum temperature below $0^{\circ}C$ in this area, can be applied to infer that the total groundwater volume used in WCC areas nationwide is no more than 55% of the total agricultural groundwater use in Korea.

• Clean Technology
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• v.17 no.4
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• pp.306-313
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• 2011

Flux or solder is used in soldering process for manufacturing electronic parts such as printed circuit boards (PCB). After soldering process, residual flux and solder paste on the parts should be removed since their residuals could cause performance degradation or failure of parts due to their corrosion and electric leakage. Ozone depletion substances such as 1,1,1- trichloroethane (TCE) and HCFC-141b have widely been using for removal of residual flux and solder paste after soldering process In manufacturing of electronic parts until now. In this study, non-aqueous cleaning agents without flash point were developed and applied to industrial field for replacement of cleaning agents with ozone depletion. In order to develop non-aqueous cleaning agents without ethers, esters, fluoride- type solvents. And their physical properties and cleaning abilities were evaluated, and they were applied to industrial fields for cleaning of flux and solder on the PCB. And vacuum distillation apparatus were operated to determine their operating conditions and recycling yields for recycling of used cleaning agents formulated in this study. As a result of physical properties measurement of our formulated cleaning agents, they were expected to have good wetting and penetrating power since their surface tensions were relatively low as 18.0~20.4 dyne/$cm^2$ and their wetting indices are relatively large. And some cleaning agents holding fluoride-type solvents as their components did not have any flash point and they seemed to be safe in their handling and storage. The cleaning experimental results showed that some cleaning agents were better in their cleaning of flux and solder paste than 1,1,1-TCE and HCFC-141b. And industrial application results of the formulated cleaning agents for cleaning PCB indicated that they can be applicable to industry due to their good cleaning capability in comparison with HCFC-141b. The recycling experiments of the used formulated cleaning agents through a vacuum distillation apparatus also showed that their 91.9~97.5% could be recycled with its proper operating conditions.

• Journal of Chest Surgery
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• v.36 no.11
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• pp.828-833
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• 2003

Background: It has been reported that the recently developed intermittent antegrade warm blood cardioplegia (IAWBC) has better myocardial protective effects during coronary artery bypass surgery than cold blood cardioplegia or continuos retrograde cold blood cardioplegia. The aim of this study is to evaluate the safety and usefulness of IAWBC by comparing it retrospectively with intermittent retrograde cold blood cardioplegia (lRCBC). Material and Method: From April 2001 to Feb. 2003, fifty seven patients who underwent isolated coronary surgery were divided into two groups (IAWBC vs. IRCBC). The two group had similar demographic and angiographic characteristics. There were no statistical differences in age, sex, Canadian Cardiovascular Society Functional Classification for angina, ejection fraction, and number of grafts. Result: Aortic cross clamping time and total pump time in IAWBC (99$\pm$23 and vs. 126$\pm$32 min) were shorter than those of IRCBC (118$\pm$32 min. and 185$\pm$48 min.)(p<0.05). The reperfusion time (13$\pm$7 min) in IAWBC was shorter than that of IRCBC (62$\pm$109 min.)(p<0.05). CKMB at 12 hours and 24 hours (16$\pm$15 and 9$\pm$13) in IAWBC was lower than that of IRCBC (33$\pm$47 and 17$\pm$26)(p<0.05). The awakening time in IAWBC (2$\pm$1 hour) was shorter than that of IRCBC (4$\pm$3)(p<0.05). The number of spontaneous heart beat recovery in IAWBC (85%) was more than that of IRCBC (35%)(p<0.05). The cardiac index after discontinuing cardio-pulmonary bypass was significantly elevated in the IAWBC group. The prevalence of perioperative myocardial infarction in IAWBC (4%) was lower than that of IRCBC group (20%)(p<0.05). Conclusion: Intermittent antegrade warm blood cardioplegia is a safe, reliable, and effective technique for myocardial protection. It can also provide simpler and economic way than the retrograde cold cardioplegia by shortening of cardiopulmonary bypass time and avoiding retrograde cannulation for coronary sinus.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.06a
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• pp.148-155
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• 2002

Multithreaded models improve the efficiency of parallel systems by combining inner parallelism, asynchronous data availability and the locality of von Neumann model. This model executes thread code which is generated by compiler and of which quality is given by the method of generation. But multithreaded models have the demerit that execution model is restricted to a specific platform. On the contrary, Java has the platform independency, so if we can translate from threads code to Java bytecode, we can use the advantages of multithreaded models in many platforms. Java executes Java bytecode which is intermediate language format for Java virtual machine. Java bytecode plays a role of an intermediate language in translator and Java virtual machine work as back-end in translator. But, Java bytecode which is translated from multithreaded models have the demerit that it is not secure. This paper, multhithread code whose feature of platform independent can execute in java virtual machine. We design and implement translator which translate from thread code of multithreaded code to Java bytecode and which check secure problems from Java bytecode.

• Journal of the Korea Organic Resources Recycling Association
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• v.26 no.1
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• pp.65-78
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• 2018

According to the in social aspects such as population growth, urbanization and industrialization, development of livestock industry by meat consumption, amount of organic wastes (containing sewage sludge and food waste, animal manure, etc) has been increased annually in South Korea. Precise monitoring of 11 organic wastes biogas facilities were conducted. The organic decomposition rate of organic wastewater was 68.2 % for food wastes, 66.8 % for animal manure and 46.2 % for sewage sludge and 58.8 % for total organic wastes. As a result of analyzing the biogas characteristics before and after the pretreatment, the total average of the whole facility was measured to be 560 ppm using iron salts and desulfurization, and decreased to 40 ppm when the reduction efficiency was above 90 %. Particularly, when iron salt is injected into the digester, the treatment efficiency is about 93 %, and the average is reduced to 150 ppm. In the case of dehumidification, the absolute humidity and the relative humidity were analyzed. The dew point temperature of the facility where the dehumidification facility was well maintained as $14^{\circ}C$, the absolute humidity was $12.6g/m^3$, and the relative humidity was 35 %. Therefore, it is necessary to compensate for the disadvantages of biogasification facilities of organic waste resources and optimize utilization of biogas and improve operation of facilities. This study was conducted to optimize biogas utilization of type of organic waste(containing sewage sludge and food waste, animal manure) through precision monitoring.

• Journal of Acupuncture Research
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• v.23 no.5
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• pp.105-113
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• 2006

Objectives : To establish an effective collaborate medicine treatment of acupuncture and western medicine for treating frozen shoulder patients. Methods : 59 voluntary patients were randomly assigned to Eastern treatment group(E group, n=22), Western treatment group(W group, n=17) and East-West treatment group(EW group, n=20). The E group received acupuncture treatment on LI15, TE14, GB21 and Master Dong's acupuncture points, Shin-gwan and Gyun-joong, twice a week for 4 weeks. The W group received suprascapular nerve block, subacromial injection and trigger point injection, twice a week for 4 weeks. The EW group received acupuncture and injection treatment including nerve block All groups were instructed to practice self exercise during their daily lives. Evaluations were made before treatment and after treatment based on the change in shoulder Range of Motion(ROM) and the patient's satisfaction concerning the treatment was measured by Visual Analogue Scale(VAS). The obtained data were analyzed and compared. Results : The patient's satisfaction scores were E group 5.67, W group 7.73 and EW group 7.67. The E group and the EW group showed significant improvement in abbduction, adduction and flexion(p<0.05). The W group showed significant improvement in adduction(p<0.05). Abduction significantly improved(p<0.05) in the EW group compared to E group and W group. Flexion also showed improvement in the EW group, but the difference among the 3 groups was statistically insignificant. The three group's difference of change in extension and adduction was insignificant(p>0.05). Conclusion : Acupuncture and nerve block alone significantly improved ROM in frozen shoulder patients. Also collaborate treatment of acupuncture and nerve block significantly improved ROM in frozen shoulder patients. But the difference of the three treatments were significant only for improving abduction(p<0.05).

• 한국지구과학회:학술대회논문집
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• 2010.04a
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• pp.88-89
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• 2010

최근 인간의 활동범위와 영역이 확대되고 산업이 발전하면서 인간의 삶과 지속가능한 발전 등 도시 기후에 관한 관심도 높아지고 있다. 산업혁명 이후 도시화와 산업화로 인해 인구가 증가하고 도시지역으로 집중됨으로써 도시 열섬화 현상에 대한 도시환경문제가 부각되고 있다. 이는 최근까지도 도시개발에 있어서 기능과 효율성이 우선시 되어 도시기후에 대한 배려가 이루어지지 못하고 있으며, 오히려 과도한 냉난방을 가동하는 등 쾌적한 실내 환경 조성을 위한 노력만을 행해왔다. 도시화에 따른 도시의 열환경 구조의 변화는 토지이용의 변화에 따른 피복상태와 밀접한 관련이 있다는 연구들이 수행된 바 있다. 이렇듯 도시화가 진행됨에 따라서 도심 지표면을 덮고 있는 포장재도 변하고 있다. 대표적인 토지피복재로는 콘크리트와 아스팔트 등의 인공포장재, 수계, 삼림 등으로 크게 나누어 볼 수 있다. 최근 도심의 발달로 인해 도심의 표면은 점차 인공포장재인 아스팔트와 콘크리트로 덮여지고 있다. 인공포장재는 맑은 여름철 낮에 받아들인 열을 야간에도 머금고 있어 도시열섬현상의 주요원인이 된다. 도시화가 진행됨에 따라 토지이용형태가 변화하고 있으며 이러한 토지피복의 변화는 그 지역의 기온과 풍향, 풍속뿐만 아니라 지표온도도 변화시키므로 도시 열환경 구조에 적지 않은 영향을 미치고 있다. 과거에는 자연 환경과 도시공간에 대한 인식이 다른 분야로 나누어져서 다루었지만 현재 위성영상 기술의 발달로 많은 공간 정보를 파악할 수 있게 된 바 도시기후변화에 더욱 직접적이고 근본적인 접근이 쉬워졌다. 원격탐사기법의 활용은 위성자료를 이용하여 동시간대 평면적인 열구조를 정량적으로 파악하는데에 중요한 자료를 제공하여 도시지역을 덮고 있는 인공자재의 존재가 도시열섬의 형성과 밀접하게 연관이 있다는 사실을 짐작할 수 있다. 따라서 도시기후변화의 문제점을 더욱 적극적으로 해결하기 위해서는 토지이용에 따른 지표면 온도 상승의 현황을 파악하고 이를 저감 시킬 수 있는 대책들이 수립되어야 한다. 본 연구는 보다 세분화된 도시 열환경을 정량적으로 분석 평가하기 위해서 토지피복별 분류를 3가지로 대구시 중구 경북대학교 부속 고등학교(이하 사대부고 지점)를 도심지역으로, 경상남도 창녕군 창녕읍 우포늪(이하 우포지점)을 수계지점으로, 경상북도 안동시 길안면 만음리(이하 안동지점) 지점과 대구시 칠곡군 동명면 득명리 팔공산 한티재 도립공원(이하 팔공지점)을 산림으로 분류하여 연구하였다. 대구 계명대학교 기후환경연구실에서 보유하고 있는 AWS(Automatic Weather Station) 자료로 기상요소를 분석하였으며, MODIS Terra 위성영상을 이용하여 지표온도를 추출하고 분석하였다. 또 기상요소와 지표온도를 이용해 회귀식을 도출하여 추정기온을 산출하였다. 그 결과 첫째, 계절에 따른 기온의 시간변화는 여름의 평균기온이 $25.13^{\circ}C$와 $24.12^{\circ}C$로 사대지점과 우포지점의 평균기온이 가장 높게 나타났으며, 이는 도심에서 발생되는 인공열의 영향으로, 우포지점은 수계의 특징이 반영된 결과라 할 수 있다. 둘째, 계절에 따른 풍속의 시간변화는 여름의 경우 우포지점의 풍속이 1.63m/s로 가장 높은 반면 안동지점의 풍속이 0.27m/s로 가장 낮은 것으로 나타났다. 겨울의 경우 팔공지점의 풍속이 1.82m/s로 가장 높게 나타났다. 토지피복에 따른 지표면의 변화가 도시기후에 미치는 영향을 정량적으로 평가하고, 또 지표면 온도와 기온과의 차이를 알아보기 위하여 MODIS 위성 영상을 이용하여 세 지점을 대상으로 토지피복에 따른 열환경을 평가 분석하여 다음과 같은 결론을 얻을 수 있었다. 첫째, MODIS 위성영상을 이용하여 산출한 지표면 온도는 여름철 주간에 안동지점의 경우 주변지역에 비해 지표면 온도가 약 $26^{\circ}C$로 낮게 나타났으며 우포지점의 경우 수계가 가지는 열 완충능력으로 약 $27^{\circ}C$의 낮은 지표면 온도를 나타내었다. 사대지점의 경우 약 $34^{\circ}C$이상의 높은 지표면 온도를 나타내었다. 둘째, MODIS 위성영상을 이용하여 산출한 지표면 온도와 관측된 기온과의 회귀식을 도출하여 상관분석 한 결과, 모든 지점의 값에서 상관성 및 신뢰도가 높은 것으로 나타났다. 셋째, 상관분석의 결과를 통하여 추정한 기온은 지표면 온도와의 차이가 있지만 유사한 패턴의 결과로 추출되었다. 이러한 결과로 볼 때 도시의 인공자재를 이용한 건축과 개발이 도시열섬현상을 유발하는데 중요한 역할을 하는 것을 정량적으로 평가할 수 있었다. 따라서 본 논문의 연구결과를 바탕으로 도시계획에 있어서 인공구조물에 의한 기온과 풍속이 받는 영향을 고려하여 도심의 인공구조물의 배치나 자재에 대한 개발이 이루어져야 할 것이며 열교환의 방해 및 바람순환이 확보되는 구조로 개선되어야 할 것이다.

• Journal of the Korean Electrochemical Society
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• v.1 no.1
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• pp.1-7
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• 1998

For the purpose of finding new cathode materials for medium-temperature $(700\~800^{\circ}C)$ solid oxide fuel cells, $Gd_{0.8}Ca_{0.2}Co_{1-x}Fe_xO_3,\;(x=0.0\~0.5)$ are prepared, and their thermal stability and conductivity characteristics are investigated. Also, the cathodic activities are measured after the cathode layer being attached on CGO (cerium-gadolinium oxide) electrolyte disk. The X-ray analyses indicate that the materials prepared by calcining the citrate-gels at $800^{\circ}C$ have the orthorhombic perovskite structure without discernible impurities. The thermal stability of the undoped Co perovskite is so poor that it is decomposed to the individual binary oxide even at $1300^{\circ}C$. But the partially Fe-doped cobaltates exhibit a better thermal stability to retain their structural integrity up to $1400^{\circ}C$. The observation whereby both the undoped and Fe-doped cobaltates melt at ca. $1300^{\circ}C$ leads us to perform the electrode adhesion at <$1300^{\circ}C$. The cathodic activity of $Gd_{0.8}Ca_{0.2}Co_{1-x}Fe_xO_3,\;(x=0.0\~0.5)$, electrodes is superior to $La_{0.9}Sr_{0.1}MnO_3$, among the samples of $x=0.0\~0.5$, the x=0.2 cathode shows the best activity for the oxygen reduction reaction. It is likely that the Fe-doping provides a better thermal stability to the materials but in turn imparts an inferior cathodic activity, such that the optimum trade-off is made at x=0.2 between the two factors. The total electrical conductivity and ion conductivity of $Gd_{0.8}Ca_{0.2}Co_{1-x}Fe_xO_3$, are measured to be 51 S/cm and $6.0\times10^{-4}S/cm\;at\;800^{\circ}C$, respectively. The conductivity values illustrate that the materials are a mixed conductor and the reaction sites can be expanded to the overall electrode surface, thereby providing a better cathodic activity than $La_{0.9}Sr_{0.1}MnO_3$.

• Korean Journal of Construction Engineering and Management
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• v.17 no.4
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• pp.103-115
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• 2016

The 106 buildings of 200 meters' height or greater were completed around the world in 2015 (CTBUH, The Council on Tall Buildings and Urban Habitat). They beat every previous year on record, including the previous record high of 99 completions in 2014. This brings the total number of 200-meter-plus buildings in the world to 1,040, exceeding 1,000 for the first time in history and marking a 392% increase from the year 2000, when only 265 existed. South Korea recorded three completions during 2015 - improving slightly over 2014, in which it had one. This study focused on the fact that high-rise building development project risks have not reduced in Korea in spite of numerous studies and measures. And it attempted to examine whether existing studies and measures have been presented on the basis of the accurate analysis of existing studies and measures and classify and analyze the characteristics of each phase' s risk factors in the hope that its results would be one reference point as to the measure to prevent high-rise building development project risks in the future. A high-rise building development project is the high risk project as compared with the low-rise project. Because a high-rise development project takes long and is very sensitive to the changing environment. Therefore, in order to succeed the project it becomes necessary to effectively manage the risk involved in the process of the high-rise building development project. The result of this study can be used as the guideline to make the risk management system for the high-rise development project.

• Computational Structural Engineering
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• v.7 no.3
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• pp.95-103
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• 1994

The safety related components in the nuclear power plant should be designed to withstand the seismic load. Among these components the integrity of reactor internals under earthquake load is important in stand points of safety and economics, because these are classified to Seismic Class I components. So far the modelling methods of reactor internals have been investigated by many authors. In this paper, the dynamic behaviour of reactor internals of Yong Gwang 1&2 nuclear power plants under SSE(Safe Shutdown Earthquake) load is analyzed by using of the simpled Global Beam Model. For this, as a first step, the characteristic analysis of reactor internal components are performed by using of the finite element code ANSYS. And the Global Beam Model for reactor internals which includes beam elements, nonlinear impact springs which have gaps in upper and lower positions, and hydrodynamical couplings which simulate the fluid-filled cylinders of reactor vessel and core barrel structures is established. And for the exciting external force the response spectrum which is applied to reactor support is converted to the time history input. With this excitation and the model the dynamic behaviour of reactor internals is obtained. As the results, the structural integrity of reactor internal components under seismic excitation is verified and the input for the detailed duel assembly series model could be obtained. And the simplicity and effectiveness of Global Beam Model and the economics of the explicit Runge-Kutta-Gills algorithm in impact problem of high frequency interface components are confirmed.