• Proceedings of the Korea Information Processing Society Conference
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• 2002.11c
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• pp.1709-1712
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• 2002

지식 탐사 연구의 핵심이 되어온 데이터 마이닝은 축적 데이터로부터 쉽게 추출되지 않는 데이터 상호관계나 일정 패턴과 같은 유용한 내재 정보 추출을 주된 목적으로 수행된다. 그러나, 데이터 마이닝은 대용량의 데이터 처리로 인해 빈번한 메모리 공간 제약과 처리 속도 저하 등의 한계성을 드러낸다. 이를 극복하기 위해 많은 마이닝 알고리즘 개발과 기존 알고리즘 개선 방법이 제시되어 왔으나 여전히 궁극적인 해결방안은 대두되지 않고 있다. 따라서, 만약 데이터 전처리 과정을 통해 마이닝 목적에 적합한 부분 데이터집합 추출 및 가공이 선행된다면 보다 효율적인 데이터 마이닝 작업을 유도할 수 있을 것이다. 본 논문은 효과적 데이터 전처리를 위한 필수 기본 연산 기능들을 주어진 데이터집합의 트랜잭션 및 데이터 특성에 기초하여 관계형 대수 형태로 의미를 정립하고, 적용 사례에 의한 상세 설명 및 실제 구현된 온라인 데이터 전처리 시스템을 제안한다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.93-97
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• 2001

시추공의 구간별 수리전도를 추정하는 방법으로는 수압시험(packer test)이 많이 이용되는데 최근에는 유속측정기(flowmeter)를 이용한 시추공 검층법이 개발되어 활발한 연구가 진행 중이다. 본 연구에서는 열원(heat-pulse) 공급 방식의 유속측정기를 이용하여 공주대학 교내에 설치된 시추공에서 자연 유속(ambient flow) 및 양수 유발 유속(pump-induced flow)을 측정하였으며, 자료를 분석하여 수리전도도의 수직적인 분포를 산정하였다. 분석 결과는 수압시험에 의해 산정된 수리전도도의 분포와 잘 일치하였으며, BIPS에 의해 촬영된 시추공 영상 자료와 비교함으로써 지하수 유동과 관련된 투수성 단열(conductive fracture) 들의 수직적인 위치를 정확하게 파악할 수 있었다. 분석 결과는 암반 대수층 내에 발달된 단열망(fracture network)에 대한 3차원적인 정보를 제공할 수 있으며, 이는 효과적인 지하수 모니터링, 모델링, 및 정화 설계(remedial design)에 필요한 기초 자료로 활용될 수 있을 것으로 기대된다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.228-231
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• 1999

3차원 공간상의 표적의 위치는 방위각, 고각, 거리의 세가지요소로 나타내어 질 수 있다. 이 논문에서는 등각적 선배열 센서로 이루어진 3개의 부분센서배열을 이용한 3차원 표적의 위치추정 알고리듬을 제안하였다. 원거리 표적의 방위각 추정 알고리듬으로 근거리 표적의 방위각을 추정하면 추정된 방위각은 실제 근거리 표적의 방위각과 고각과 거리의 비선형 대수적 관계식으로 주어진다. 제안한 알고리듬은 3개의 부분센서배열에서 각각 표적을 원거리에 있다고 가정하고 원거리입체각을 추정하여 위의 대수적 관계식을 얻은 후 이들 관계식을 연립하여 실제 근거리 표적의 위치를 추정하였다. 다중표적의 경우 각각의 부분센서배열에서 추정한 원거리입체각이 어떤 표적에 대한 추정치인지 연관시켜주는 알고리듬이 필요하다. 이 논문에서는 추정한 원거리입체각의 모든 조합으로부터 3차원 MUSIC 스펙트럼값을 비교하여 그 중 표적의 개수만큼을 선별하여 다중표적의 위치를 추정하였다.

• Korean journal of applied entomology
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• v.31 no.4
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• pp.360-365
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• 1992

Leaf feeding insect species of welsh onion and shallot were surveyed, and their species abundances were analyzed by fitness test for lognomal disstribution. A total of 13 and 6 species were identified on welsh onion and shallot, respectively. The dominant species on welsh onion were Thrips tabacid, Acrolepiopsis sapporensis, Spodoptera exigua, and Liriomyza chinensis. Thrips tabacid was also identified as the major species on the shallot. The community dominance was high in welsh onion and shallot observed on 12 October, Suwon. The species abundance patterns of the two communities were well described by lognormal distribution(P> 0.50).

• New & Renewable Energy
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• v.17 no.3
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• pp.32-41
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• 2021

A groundwater source heat pump (GWHP) was developed in this study by adapting a borehole heat exchanger with closed-loop and open-loop systems in a new building. In the pilot test building, the air-conditioning on the second floor was designed to employ a closed-loop system and that on the third floor had an open-loop system. The GWHP design is based on the feasibility of groundwater resources at the installation site. For the hydrogeological survey of the study site, pumping and injection tests were conducted, and the feasibility of GWHP installation was evaluated based on the air-conditioning load demand of the building. The site was found to be satisfactory for the design capacity of the thermal load and water quality. In addition, the effect of groundwater movement on the performance of the closed-loop system was tested under three different operational scenarios of groundwater pumping. The performance of the system was sustainable with groundwater flow but declined without appropriate groundwater flow. From long-term observations of the operation, the aquifer temperature change was less than 2℃ at the observation well and 5℃ at the injection well with respect to the initial groundwater temperature. This pilot study is expected to be of guidance for developing GWHPs at fractured rock aquifers.

• Journal of the Korea Society for Simulation
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• v.19 no.3
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• pp.109-117
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• 2010

In this study, we consider stationary waiting times in a simple fork-and-join type queue which consists of three single-server machines, Machine 1, Machine 2, and Assembly Machine. We assume that the queue has a renewal arrival process and that independent service times at each node are either deterministic or non-overlapping. We also assume that the Machines 1 and 2 have an infinite buffer capacity whereas the Assembly Machine has two finite buffers, one for each machine. Services at each machine are given by FIFO service discipline and a communication blocking policy. We derive the explicit expressions for stationary waiting times at all nodes as a function of finite buffer capacities by using (max,+)-algebra. Various characteristics of stationary waiting times such as mean, higher moments, and tail probability can be computed from these expressions.

• Communications of Mathematical Education
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• v.17
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• pp.97-114
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• 2003

일선 교육 현장에서 영재를 지도함에 있어서 해결해야 할 당면 과제는 판별 도구와 학습 프로그램의 개발이다. 영재를 위한 수학 프로그램을 문제 해결형, 수학 탐구형, 과제 해결형의 3가지로 분류할 경우, 퍼즐은 문제 해결형과 수학 탐구형 프로그램의 특성을 공통적으로 갖고 있는 유형으로 수학적 지식의 통합과 연결성. 그리고 창의적 문제 해결력 신장 및 수학적 원리 ${\cdot}$ 법칙을 체험적으로 만들 수 있는 기회를 제공한다는 점에서 매우 가치있는 프로그램이다. 특히 조작퍼즐은 기존의 대수적 표현 체계로 학습하기가 힘든 관찰력이나 공간에 대한 인식과 표현력 친 공간 추론력을 기르는 데 유용하며, 게임적인 요소가 포함된 퍼즐은 지필에 의존해 왔던 수학학습에 대한 부정적인 인식을 해소하는 데 크게 기여할 것이다. 본 고에서는 수학 퍼즐의 종류 및 특성과 교육적 가치에 대해서 개괄적으로 살펴보고, 실제 프로그램 작성을 위한 정보를 제공과 영재들의 공감 감각을 기르기 위한 프로그램의 원을 이용한 수학 퍼즐의 개요를 제시한다.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.64-72
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• 2009

The method to generate a digital elevation model(DEM) from contour lines causes a problem in which the low relief landform cannot be clearly presented due to the fact that it is significantly influenced by the expression of micro landform elements according to the interval of contours. Thus, this study attempts to develop a landcover burning method that recovers the micro relief landform of the DEM, which applies buffering and map algebra methods by inputting the elevation information to the landcover. In the recovering process of the micro landform, the DEM was recovered using the buffering method and elevation information through the map algebra for the landcover element for the micro landform among the primary DEM generation, making landcover map, and landcover elements. The recovering of the micro landform was applied based on stream landforms. The recovering of landforms using the buffering method was performed for the bar, which is a polygonal element, and wetland according to the properties of concave/convex through generating contours with a uniform interval in which the elevation information applied to the recovered landform. In the case of the linear elements, such as bank, road, waterway, and tributary, the landform can be recovered by using the elevation information through applying a map algebra function. Because the polygonal elements, such as stream channel, river terrace, and artificial objects (farmlands) are determined as a flat property, these are recovered by inputting constant elevation values. The results of this study were compared and analyzed for the degree of landform expression between the original DEM and the recovered DEM. In the results of the analysis, the DEM produced by using the conventional method showed few expressions in micro landform elements. The method developed in this study well described wetland, bar, landform around rivers, farmland, bank, river terrace, and artificial objects. It can be expected that the results of this study contribute to the classification and analysis of micro landforms, plain and the ecology and environment study that requires the recovering of micro landforms around streams and rivers.

• Economic and Environmental Geology
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• v.43 no.4
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• pp.359-369
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• 2010

This study characterizes aquifer system and hydrogeologic property in the western half of Jeju Island where wells were drilled for regional water supply in three sub-areas (northwestern, western, and southwestern sub-areas). The aquifer system of the northwestern sub-area is largely composed of upper high-permeability layer, upper low-permeability layer, lower high-permeability layer, and lower low-permeability layer. On the other hand, the aquifer systems of the western and southwestern sub-areas are mostly composed of upper low-permeability layer, high-permeability layer, and lower low-permeability layer. Transmissivity and specific capacity decrease in the order of the northwestern, western, and southwestern sub-areas. The relationship between specific capacity and the top surface of tuff is negative with a high correlation coefficient of -0.848, indicating that the tuff acts as the bottom of the aquifer. Groundwater level change due to the 2004 Sumatra earthquake is an average of 23.74 cm in the northwestern sub-area, an average of 9.48 cm in the western sub-area, and none in the southwestern sub-area. Further, it is found that groundwater change due to the earthquake has a positive relationship with transmissivity and specific capacity.

• The Journal of Engineering Geology
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• v.24 no.2
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• pp.201-215
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• 2014

This study was performed to investigate the correlation between hydraulic conductivity and the flow rate of an aquifer, with the flow rate calculated from the laterals of the radial collector well using data obtained by the development project of riverbank filtration (Second Phase) in Changwon City. The hydraulic conductivity was empirically calculated from unconsolidated sediments collected from a sandy gravel layer along the middle-to-downstream sections of the Nakdong River. The Beyer equation produced the most suitable hydraulic conductivity from the various empirical formulas employed. The calculated hydraulic conductivity ranged from 0.083 to 0.264 cm/s, with an average value of 0.159 cm/s, suggesting that the aquifer in the study area possesses a high permeability with a good distribution of sandy gravel. The relationship between the calculated hydraulic conductivity in the aquifer and the entrance velocity into the screen, the flow rate was analyzed through the linear regression analysis. From the result of regression analysis, it showed that the hydraulic conductivity and the entrance velocity into the screen and the flow rate have a linear regression equation having about 72% of the high correlation. The result of verification in the measured data between each variable showed a high suitability from being consistent with the approximately 72% in the linear regression analysis. This study demonstrates that the groundwater flow rate can be estimated within the laterals of the radial collector well using a linear regression equation, if the hydraulic conductivity of the aquifer is known. This methodology could thus be applicable to other aquifers with hydraulic conductivity and permeability parameters similar to those in the present study area.