• Journal of KIISE:Databases
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• v.33 no.3
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• pp.271-281
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• 2006

Recently the need for Location-Based Service (LBS) has increased due to the development and widespread use of the mobile devices (e.g., PDAs, cellular phones, labtop computers, GPS, and RFID etc). The core technology of LBS is a moving-objects database that stores and manages the positions of moving objects. To search for information quickly, the database needs to contain an index that supports both real-time position tracking and management of large numbers of updates. As a result, the index requires a structure operating in the main memory for real-time processing and requires a technique to migrate part of the index from the main memory to disk storage (or from disk storage to the main memory) to manage large volumes of data. To satisfy these requirements, this paper suggests a unified index scheme unifying the main memory and the disk as well as migration policies for migrating part of the index from the memory to the disk during a restriction in memory space. Migration policy determines a group of nodes, called the migration subtree, and migrates the group as a unit to reduce disk I/O. This method takes advantage of bulk operations and dynamic clustering. The unified index is created by applying various migration policies. This paper measures and compares the performance of the migration policies using experimental evaluation.

• Journal of Soil and Groundwater Environment
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• v.13 no.5
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• pp.33-46
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• 2008

A series of three-dimensional numerical simulations using a generalized multidimensional hydrodynamic dispersion numerical model is performed to simulate effectively and to evaluate quantitatively impacts of fault existence on densitydependent groundwater flow and salt transport in coastal aquifer systems. A series of steady-state numerical simulations with calibration is performed first for an actual coastal aquifer system which contains a major fault. A series of steadystate numerical simulations is then performed for a corresponding coastal aquifer system which does not have such a major fault. Finally, the results of both numerical simulations are compared with each other and analyzed. The results of the numerical simulations show that the major fault produces hydrogeologically significant heterogeneity and true anisotropy in the actual coastal aquifer system, and density-dependent groundwater flow, salt transport, and seawater intrusion patterns in the coastal aquifer systems are intensively and extensively dependent upon the existence or absence of such a major fault. Especially, the major fault may act as a pathway for groundwater flow and salt transport along the direction parallel to its plane, while it may also behave as a barrier against groundwater flow and salt transport along the direction perpendicular to its plane.

• Research in Plant Disease
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• v.19 no.4
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• pp.273-280
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• 2013

Tomato spotted wilt virus (TSWV) was occurred at 8 areas including Naju, Suncheon, Younggwang, Youngam, and Shinan in Jeonnam province and the crops of Younggwang were severely damaged by TSWV. The hot pepper (Capsicum annuum), bell pepper (Capsicum annuum v ar. angulosum) and tomato (Solanum lycopersicon) in greenhouse and hot pepper in open field were infected by TSWV. Especially, hot pepper was severely damaged by TSWV infection. The survey data indicated that 1.1-30% in the nursery field at Naju, Suncheon, and Jangheung were infected by TSWV. Plants were infected by TSWV from early June to August. However, TSWV-infected seedlings from nursery fields showed the disease symptoms from May after transplanting. In pepper greenhouses, Frankliniella occidentalis was more dominant insect vector than Frankliniella intonsa. But in open field, the population of insect vector was opposed to greenhouse. In addition, the removal of weeds was able to delay the incidence of TSWV via side-window of greenhouse in Winter. Taken together, the control of weed and insect vector nearby side-window of greenhouse is important to prevent TSWV infection of plants.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.18 no.3
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• pp.198-210
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• 2006

POM(Princeton Ocean Model) was utilized in this study because it took ${\sigma}-coordinate$ system which could predict the behavior of bottom water. The model has been increasingly applied to costal area although it was initially developed as the ocean flow model. The original POM did not correct computational errors in transformation of ${\sigma}-coordinate$ system. The trying to reduce conversional errors might improve accuracy of flow velocity in vicinities of bottom layer. Therefore, in this study it was proposed to modify the original POM by using error correction method suggested by $Sl{\Phi}rdal$(1997). The modified POM was applied to Young-rang Lake, one of the typical brackish lakes in Korea. It was found that the behavior of bottom water could be well predicted. Thus, it seems that the modified POM can be used as a useful tool to clarify the mechanism of formation and behavior of bottom water including oxygen-deficient water mass.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.253-263
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• 1993

Climatological informations have not been fully utilized by agricultural research and extension workers in Korea due mainly to inaccessbilty to the archived climate data. This study was initiated to improve access to historical climate data gathered from 72 weather stations of Korea Meteorological Administration for agricultural applications by using a microcomputer-based methodology. The climatological elements include daily values of average, maximum and minimum temperature, relative humidity, average and maximum wind speed, wind direction, evaporation, precipitation, sunshine duration and cloud amount. The menu-driven, user-friendly data retrieval system(CLIDAS) provides quick summaries of the data values on a daily, weekly and monthly basis and selective retrieval of weather records meeting certain user specified critical conditions. Growing degree days and potential evapotranspiration data are derived from the daily climatic data, too. Data reports can be output to the computer screen, a printer or ASCII data files. CLIDAS can be run on any IBM compatible machines with Video Graphics Array card. To run the system with the whole database, more than 50 Mb hard disk space should be available. The system can be easily upgraded for further expansion of functions due to the module-structured design.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.596-602
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• 2019

In September 2017, the rhizospheric soil of Tetragonia tetragonoides (Pall.) Kuntze was further sampled. One hundred and thirty eight species of microorganisms were isolated from the soil. Indole-3-acetic acid (IAA) production, siderophore production, and phosphate degradation were examined in order to confirm bacterial growth from isolated microorganisms. As a result, most strains were able to produce auxins or siderophores and to solubilize phosphate. In addition, 138 isolated strains were treated with tobacco extract and conferred pathogen resistance to host plants upon treatment. As a result, 35 strains that were able to reduce pathophysiology by more the 60% were selected. Among them, 6 strains with high induced systemic resistance (ISR) activity were found. All of these strains belong to the genus Bacillus according to the 16S rDNA sequence analysis. Bacillus aryabhattai KUDC6619 showed outstanding effects with reduced infection in tobacco and pepper plants. Probably, these Bacillus species play a beneficial role by association with T. tetragonoides for its survival in the harsh conditions found on the island of Dokdo.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.777-784
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• 2006

This study was designed to investigate between the semen characteristics and sperm chromatin structure in boar with different farrowing rates and relationship between fertility by AI and results of sperm chromatin structure assay (SCSA). The CASA (computer-aided sperm analysis) and SCSA were performed with liquid semen in boars. The all SCSA parameters based on the farrowing rates by AI were significantly differ (P<0.05). The significant negative correlations (P<0.05) were observed between all SCSA parameters and farrowing rate obtained by AI in the field. In conclusion, these results suggest that the sperm parameters evaluated in these studies may be useful indicators to predict the fertility by AI.

• Journal of Animal Science and Technology
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• v.48 no.6
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• pp.785-796
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• 2006

This study was designed to evaluate the changes in sperm motility, viability, HOST(hypo-osmotic swelling test), IVP(in vitro penetration), SCSA(sperm chromatin structure assay) during storage of liquid semen collected from boars with different farrowing rates using AI, and to find the relationship between boar fertility through AI and sperm diagnostic parameters during semen storage. The results of HOST were significantly decreased according to the increasing of in semen storage days and the results of IVP were significantly decreased at 3 days of semen storage (P<0.05). The %Red was significantly different among the >80%, 70󰠏80% and <70% farrowing rate group at semen storage day 6(P<0.05). The correlation coefficients between the %Red and farrowing rate were increased according to the semen storage. In conclusion, these results suggest that the sperm parameters evaluated in these studies may be useful indicators to predict the fertility of AI and evaluate the semen quality in boars.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.155-155
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• 2011

일반적으로 I형 보에 횡하중이 작용하는 경우, 횡 변위와 함께 회전을 동반하는 횡-비틀림 좌굴(Lateral-Torsional Buckling)이 발생하게 된다. 이러한 I형 보의 탄성 및 비탄성 횡-비틀림 좌굴에 대한 해석적 이론적 연구는 이미 많은 연구자들에 의해 수행되었다(Timoshenko 등, 1961; Galambos, 1963; Lindner, 1974; Trahair, 1993). I형 보의 비지지 길이 내 하중이 작용할 때 모멘트 구배계수(Cb)는 하중이 부재 단면에 작용하는 위치에 따라 달라지게 되는데 이를 하중고 효과(Load Height Effects)라고 한다. 탄성 영역 내 비지지길이가 존재하는 I형 보의 하중고 효과를 고려한 모멘트 구배계수 제안식은 Nethercot & Rockey(1971)에 의해 연구된 바 있다. 또한 Helwig 등(1997)은 Nethercot & Rockey(1971)의 제안식을 간략화 하여 탄성 영역 내 비지지길이가 존재하는 I형 보의 하중고 효과를 고려한 모멘트 구배계수식을 제안하였다. 그러나 현재까지 진행 된 하중고 효과에 대한 연구는 탄성 영역 내 비지지 길이가 존재하는 I형 보에 대한 제안식이며 현재까지 비탄성 영역 내 비지지 길이를 갖는 I형 보의 하중고 효과에 대한 연구는 진행된 바 없다. 본 연구는 비탄성 영역 내 비지지 길이가 존재하는 I형 보의 하중고 효과를 고려한 비탄성 횡-비틀림 좌굴강도에 대한 연구를 수행하였다. 하중조건으로는 집중하중 과 등분포 하중을 적용시켰으며, 비선형 횡-비틀림 좌굴 해석을 위해 잔류응력 및 초기변형을 고려하였다. Pi와 Trahair(1995)이 고려한 단순직선분포를 잔류응력으로 가정하였으며, 국내 I형강 표준 치수 허용치(현대제철, 2006)에 근거하여 부재 길이의 0.1%를 초기 최대 횡 변위로 적용하여 초기제작오차로 고려하였다. 유한요소해석결과를 바탕으로 Nethercot & Rockey(1971)와 Helwig 등(1997)의 연구내용을 바탕으로 범용구조해석 프로그램(ABAQUS, 2007)을 이용하여 비탄성 영역 내 존재하는 I형보의 횡-비틀림 좌굴강도를 산정하였다. 유한요소해석결과를 바탕으로 Nethercot & Rockey(1971)및 Helwig 등(1997)의 모멘트구배계수 제안식과 비교 분석 하였고 회기분석프로그램 MINITAB(2006)을 이용하여 비탄성 영역 내 비지지길이가 존재하는 I형보의 하중고 효과를 고려한 모멘트구배계수식을 개발 제안하였다. 본 연구에서 개발된 제안식은 경제적이고 합리적인 휨부재 강도평가에 적극 활용될 수 있으며, 비탄성 영역내 I형보의 횡-비틀림 좌굴강도 및 휨강도 연구에 널리 활용될 것이다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.4
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• pp.239-247
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• 2013

Recently renewable energy such as offshore wind energy takes a higher interest due to the depletion of fossil fuel and the environmental pollution. This paper deals with multi-body dynamics (MBD) analysis technique for offshore wind turbine system considering aerodynamic loads and Thevenin equation used for determination of electric generator torque. Dynamic responses of 5MW offshore wind turbine system are evaluated via the MBD analysis, and the system is the horizontal axis wind turbine (HAWT) which generates electricity from the three blades horizontally installed at upwind direction. The aerodynamic loads acting on the blades are computed by AeroDyn code, which is capable of accommodating a generalized dynamic wake using blade element momentum (BEM) theory. In order that the characteristics of dynamic loads and torques on the main joint parts of offshore wind turbine system are simulated similarly such an actual system, flexible body modeling including the actual structural properties are applied for both blade and tower in the multi-body dynamics model.