• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.291-299
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• 2016

Recently, the knowledge industry center has played a role as a facility that creates economic added value because of the high-tech companies related to the knowledge industry, information, and communication. On the other hand, support facilities that are provided in the knowledge industry center are meant to support the company in the center and improve the working conditions of laborers. On the other hand, the support policy established by the government applies to some companies, and none of the support policy is carried out in supporting facilities in the knowledge industry center. In this study, multiple analysis was performed, focusing on the support facilities in the knowledge industry center that aims to improve the working environment of laborers. This study suggests the introduction of guidelines to secure adequate area, depending on the type of supporting facilities in the Knowledge Industrial Center. The sharing of facilities, such as cultural and commercial use for Knowledge Industrial Center, corresponding to poor provision, is recommended. Because the analysis of IPA indicates that the area of commercial support facilities are higher than others and cultural facilities are more important and preferred, it is necessary to compose support facilities that consider the user's individual characteristics. Facilities impacting the working environment need to be planned carefully through a district unit plan at the initial stages of development, thus assisting the production activity of workers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.61-69
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• 2016

Since 2000, the market of convenient stores in Korea has developed rapidly due to the explosive growth in single households but it still consists mainly of manual work due to the nature of the domestic industry. Hence the explosive increase in demand in the market is mostly due to workers. Therefore, the research aimed at encouraging efficiency via automation, which is carried out in manufacturing, such as electronic, cars and so on, is inadequate. This study performed a feasibility analysis of investment for introducing an automated system on brand A, which is domestic famous convenience store company. Productivity growth according to the introduction of an automated guided vehicle and the cost-benefits was studied with using a simulation for the picking process, which is most personnel and time consuming. As a result, the simulation showed that the equipment AGV introduced for choosing the process has the effects of cost saving and increased time efficiency for performing manual labor. Furthermore, appropriate numbers of AGV were forecasted considering the capacity of the distribution Center in the brand A convenient store, which has been growing steadily. There are increasing numbers of worker labor costs in the distribution industry these days. Before building a large new automate center, it is expected to provide a good information to investors who are considering increasing productivity through partial automation of each of unit process to achieve some cost reduction.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.4
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• pp.579-586
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• 2018

Short-term prediction of travel speed has been widely studied using data-driven non-parametric techniques. There is, however, a lack of research on the prediction aimed at urban areas due to their complex dynamics stemming from traffic signals and intersections. The purpose of this study is to develop a hybrid approach combining ensemble empirical mode decomposition (EEMD) and artificial neural network (ANN) for predicting urban travel speed. The EEMD decomposes the time-series data of travel speed into intrinsic mode functions (IMFs) and residue. The decomposed IMFs represent local characteristics of time-scale components and they are predicted using an ANN, respectively. The IMFs can be predicted more accurately than their original travel speed since they mitigate the complexity of the original data such as non-linearity, non-stationarity, and oscillation. The predicted IMFs are summed up to represent the predicted travel speed. To evaluate the proposed method, the travel speed data from the dedicated short range communication (DSRC) in Daegu City are used. Performance evaluations are conducted targeting on the links that are particularly hard to predict. The results show the developed model has the mean absolute error rate of 10.41% in the normal condition and 25.35% in the break down for the 15-min-ahead prediction, respectively, and it outperforms the simple ANN model. The developed model contributes to the provision of the reliable traffic information in urban transportation management systems.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.167-167
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• 2017

스마트팜 내부의 3차원 공간의 온도, 습도, 기압, 공기질 분석을 통한 돈사 미세 조절 기술에 대한 연구가 진행 중이다. 해당 특성 중에서 기압을 제외한 환경인자들은 돈사 내의 구조 특성상 위치별로, 시간별로 매우 상이한 변이의 형태를 보인다. 일정 시점을 기준으로 계측 지점 이외의 지점에 대한 환경인자들을 공간적으로 추정하는 기술은 대표적으로 컴퓨터 분석 기술에 의존하고 있다. 시간 복잡도가 매우 높은 CFD(Computer Fluid Dynamics) 방식은 정밀도 측면에서 유리하나, 상응하는 제어 기술/하드웨어 등의 부재로 모델링 결과의 활용도가 낮다고 볼 수 있다. 본 연구에서는 CFD를 수행하는 과정에 있어 실질적으로 유효한 단위로 공간 분해능을 낮추고, 동등한 크기의 세부 공간에 대한 모델링을 병렬적으로 수행하기 위한 방안을 연구하였다. 실험적으로 돈사 환경을 3차원으로 구성하기 위하여, 공기 흡입구, 배출구, 기둥, 덕트 요소를 포함시켰다. 실내 공간을 1차적으로 가로, 세로, 높이방향으로 $3{\times}3{\times}3$ 균등 분배한 후 3차원 행렬로 분할하였다. 각 분할된 행렬에 대한 연산 수행을 위하여 현재까지 대중에 공개된 SBC(Single Board Computer) 중 가장 높은 연산 수행 능력이 있는 Odroid-XU4(Hardkernel, AnYang, Korea) 16식을 병렬 클러스터링 기술로 연동하였다. 하나의 AP당 8개의 코어가 내장되어 있으므로, 총 128개의 코어를 이용하여 동시에 128개의 3D 정방행렬 연산이 가능하도록 구성하였다. 모델링을 위한 수학적 모델로는 실험적으로 Steady turbulent model (Newtonian coefficient)을 이용하였다. 클러스터링을 이용한 병렬 처리의 특성상 균등한 정보량을 동시에 배분해야 하므로 108 ($27{\times}4$)개의 코어를 이용하여 1차적으로 나뉜 공간을 다시 4등분하여 동시에 $12{\times}12{\times}12$에 해당하는 공간 분해능에 대한 처리를 동시에 수행할 수 있도록 하였다. 2단계에 걸쳐 분할한 공간 세그먼트에 대한 클러스터링 연산 수행 결과 초당 15회 정도의 연산을 수행할 수 있었으며, 시간 분해능을 100으로 설정한 경우 약 5초가 수행되었다. 선행적으로 수행하였던 CFD 모델링 (OpenFOAM)과 비교하였을 때 상대적으로 정밀도가 낮은 3차원 모델링 결과를 얻을 수 있었다. 모델링에 소요되는 시간을 비약적으로 경감 시킨 장점을 살려 적정한 공간 분할 기법과 추가로 발생하는 다수의 바운더리 조건을 근사적으로 추정할 수 있는 데이터 마이닝 기술이 보완되어야 할 것이다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.161-161
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• 2017

스마트 시설환경의 제어 요소는 난방기, 창 개폐, 수분/양액 밸브 개폐, 환풍기, 제습기 등 직접적으로 시설환경의 조절에 관여하는 인자와 정보 교환을 위한 통신, 사용자 인터페이스 등 간접적으로 제어에 관련된 요소들이 복합적으로 존재한다. PID 제어와 같이 하는 수학적 논리를 바탕으로 한 제어와 전문 관리자의 지식을 기반으로 한 비선형 학습 모델에 의한 제어 등이 공존할 수 있다. 이러한 다양한 요소들을 복합적으로 연동시키기 위해선 기존의 시퀀스 기반 제어 방식에는 한계가 있을 수 있다. 관행의 방식과 같이 시계열 상에서 획득한 충분한 데이터를 이용하여 제어의 양과 시점을 결정하는 방식은 예외 상황에 충분히 대처하기 어려운 단점이 있을 수 있다. 이러한 예외 상황은 자연적인 조건의 변화에 따라 불가피하게 발생하는 경우와 시스템의 오류에 기인하는 경우로 나뉠 수 있다. 본 연구에서는 실시간으로 변하는 시설환경 내의 다양한 환경요소를 실시간으로 분석하고 상응하는 제어를 수행하여 수학적이며 예측 가능한 논리에 의해 준비된 제어시스템을 보완할 방법을 연구하였다. 과거의 고성능 컴퓨팅(HPC; High Performance Computing)은 다수의 컴퓨터를 고속 네트워크로 연동하여 집적적으로 연산능력을 향상시킨 기술로 비용과 규모의 측면에서 많은 투자를 필요로 하는 첨단 고급 기술이었다. 핸드폰과 모바일 장비의 발달로 인해 소형 마이크로프로세서가 발달하여 근래 2 Ghz의 클럭 속도에 이르는 어플리케이션 프로세서(AP: Application Processor)가 등장하기도 하였다. 상대적으로 낮은 성능에도 불구하고 저전력 소모와 플랫폼의 소형화를 장점으로 한 AP를 시설환경의 실시간 제어에 응용하기 위한 방안을 연구하였다. CPU의 클럭, 메모리의 양, 코어의 수량을 다음과 같이 달리한 3가지 시스템을 비교하여 AP를 이용한 마이크로 클러스터링 기술의 성능을 비교하였다.1) 1.5 Ghz, 8 Processors, 32 Cores, 1GByte/Processor, 32Bit Linux(ARMv71). 2) 2.0 Ghz, 4 Processors, 32 Cores, 2GByte/Processor, 32Bit Linux(ARMv71). 3) 1.5 Ghz, 8 Processors, 32 Cores, 2GByte/Processor, 64Bit Linux(Arch64). 병렬 컴퓨팅을 위한 개발 라이브러리로 MPICH(www.mpich.org)와 Open-MP(www.openmp.org)를 이용하였다. 2,500,000,000에 이르는 정수 중 소수를 구하는 연산에 소요된 시간은 1)17초, 2)13초, 3)3초 이었으며, $12800{\times}12800$ 크기의 행렬에 대한 2차원 FFT 연산 소요시간은 각각 1)10초, 2)8초, 3)2초 이었다. 3번 경우는 클럭속도가 3Gh에 이르는 상용 데스크탑의 연산 속도보다 빠르다고 평가할 수 있다. 라이브러리의 따른 결과는 근사적으로 동일하였다. 선행 연구에서 획득한 3차원 계측 데이터를 1초 단위로 3차원 선형 보간법을 수행한 경우 코어의 수를 4개 이하로 한 경우 근소한 차이로 동일한 결과를 보였으나, 코어의 수를 8개 이상으로 한 경우 앞선 결과와 유사한 경향을 보였다. 현장 보급 가능성, 구축비용 및 전력 소모 등을 종합적으로 고려한 AP 활용 마이크로 클러스터링 기술을 지속적으로 연구할 것이다.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.77-100
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• 2019

This study aims to analyze and compare centrality and brokerage measures of journal citation network focusing on textmining research. The analytic sample was 193 academic articles collected from 136 KCI journals published in 2018. The journal citation network was constructed based on citation relations. The characteristics, centralities, and brokerages of network was analyzed. The journal citation network consisted 136 nodes and 413 links with directed and weight. According to the five types of centrality(out-degree, in-degree, out-closeness, in-closeness, betweenness), journals of social sciences, engineering, and interdisciplinary research showed higher centrality. Social sciences, engineering and interdisciplinary research journals also showed higher brokerages as a result of brokerage analysis which identify five types of brokerage roles(coordinator, gatekeeper, representative, consultant, liaison). The centralities and brokerages of journals are positively correlated. This study suggested how to construct journal citation network from the articles focusing on certain topics. This was meaningful study in terms of conducting brokerage analysis and comparing it with centrality in the journal citation network.

• Journal of Venture Innovation
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• v.2 no.2
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• pp.117-126
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• 2019

This study conducted correlation analysis and multiple regression analysis using financial statements, loan structure, ROA and ROA volatility of domestic commercial banks, regional banks and special banks for the past five years (2012 ~ 2016). The result is as follows. First, as a result of correlation analysis, bank's ROA is positively related to household loans and SME loans, but it is negatively correlated with the ratio of loans to large companies, sector bias, and loan loss provision ratio. Second, ROA volatility was negatively related to household loans and SME loans, but it was positively correlated with large corporate loans, sector bias ratio, and loan loss provision ratio. Third, as a result of the regression analysis, the variables that have a statistically significant effect on the ROA volatility of banks were household loans, SME loans, and large enterprise loans. From these empirical results, special banks with high volatility in profits need to diversify loan types and sectors in order to achieve business performance outside of policy finance. and Especially, Suhyup Bank and Nonghyup Bank, which have a large commercial role, have a large size per unit by focusing on short-term profit and Rather than focusing on large companies or large loans that are easy to obtain financial information, it is necessary to focus management capabilities on household loans and SME loans by developing capabilities such as screening techniques.

• Journal of the Economic Geographical Society of Korea
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• v.17 no.2
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• pp.385-401
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• 2014

This research analyses spatial and temporal characteristics of the academic performances of high school students by using all 2,065,166 SAT scores for 3 years. The spatial inequalities in Seoul are analysed by DBMS and GIS. Based on three-year raw data of Korean SAT scores, the spatial and temporal characteristics of academic performances are scrutinized: 868,029 SAT scores cases of 2000 academic year on Novemver 17, 1999, 609,258 cases in 2005 academic year on November 17, 2004 and 587,890 cases in 2009 on November 13. The result shows that there are significant spatial disparities of the level of academic performance in Seoul by Gu level, also indicating that the disparities are getting wider over the course of time. The widening disparities by Gu level means that educational spatial inequality is intensified in spite of the increasing overall trend of academic performance of Seoul. It is also notable that disparities between regions are distinctive, while those in regions are not significant and sustained constant as time flows.

• Journal of Korean Society of Forest Science
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• v.89 no.4
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• pp.480-487
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• 2000

Repeated measurement of 472 permanent subplots in slash pine (Pinus elliottii Engelm.) plantations were used to develop survival prediction equations for predicting future number of planted slash pine trees. On the average, about 40 percent of the slash pines in the experimental sites had a stem cankers due to fusiform rust (Cronartium quercuum [Berk.] Miyabe ex Shirai f. sp. fusiforme) incidence. A stand level survival prediction model was developed that incorporated the incidence of fusiform rust and allowed the transition paths of trees from an uninfected stage to an infected stage. Predicted total surviving number of trees is obtained by adding together the predicted number of infected and uninfected trees. The influence of natural hardwood density and site quality on slash pine survivals tended to show a negative effects on future survivals.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.122-131
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• 2016

This study was conducted to analyze the effect of climatic variables on tree-ring growth of Larix leptolepis distributed in Korea by dendroclimatological method. For this, annual tree-ring growth data of Larix leptolepis collected by the $5^{th}$ National Forest Inventory were first organized to analyze yearly growth patterns of the species. To explain the relationship between tree-ring growth of Larix leptolepis and climatic variables, monthly temperature and precipitation data from 1950 to 2010 were compared with tree-ring growth data for each county. When tree-ring growth data were analyzed through cluster analysis based on similarity of climatic conditions, six clusters were identified. In addition, index chronology of Larix leptolepis for each cluster was produced through cross-dating and standardization procedures. The adequacy of index chronologies was tested using basic statistics such as mean sensitivity, auto correlation, signal to noise ratio, and expressed population signal of annual tree-ring growth. Response function analysis was finally conducted to reveal the relationship between tree-ring growth and climatic variables for each cluster. The results of this study are expected to provide valuable information necessary for estimating local growth characteristics of Larix leptolepis and for predicting changes in tree growth patterns caused by climate change.