• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.6
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• pp.391-398
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• 2023

In this paper, a penalized maximum likelihood estimation (PMLE) method that applies a penalty to increase the accuracy of a basis-screening-based Kriging model (BSKM) is introduced. The maximum order and set of basis functions used in the BSKM are determined according to their importance. In this regard, the cross-validation error (CVE) for the basis functions is employed as an indicator of importance. When constructing the Kriging model (KM), the maximum order of basis functions is determined, the importance of each basis function is evaluated according to the corresponding maximum order, and finally the optimal set of basis functions is determined. This optimal set is created by adding basis functions one by one in order of importance until the CVE of the KM is minimized. In this process, the KM must be generated repeatedly. Simultaneously, hyper-parameters representing correlations between datasets must be calculated through the maximum likelihood evaluation method. Given that the optimal set of basis functions depends on such hyper-parameters, it has a significant impact on the accuracy of the KM. The PMLE method is applied to accurately calculate hyper-parameters. It was confirmed that the accuracy of a BSKM can be improved by applying it to Branin-Hoo problem.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1919-1927
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• 2014

In order to decide the location of appropriate onshore wind farm with higher potential wind energy, several decision processes using Geographic Information System (GIS) including Digital Elevation Map (DEM) were proposed and we also estimated the wind resources through the proposed decision process. Decision process consists with three steps. First step is excluding inappropriate location geographically using DEM data including SRTM (Shuttle Radar Topography Mission) terrain data, landslide, land-use, roadway, and forest road data. And the second step of decision process is consideration of the difficulty caused by the natural environmental problem. This step is carried out using ECVAM (Environmental Conservation Value Assessment Map) data. And final step is determination of the most suitable location through the Moving Suitability Identification Method (MSIM) based on the moving potentially estimated wind resources area. Proposed decision process was applied over the Korean Peninsula. Wind resource potential estimated by the first and the second step is cases shows 35.09 GW and 7.17 GW, respectively, and the total evaluated energy from the all proposed step were 0.43 GW and 1.87 GW for the 3 km and 1.5 km geographical grid size, respectively.

• Explosives and Blasting
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• v.31 no.2
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• pp.32-39
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• 2013

Generally, The way of long hole blasting is carried out in coal-face, basic excavation for dam, mine etc. Recently, this long hole blasting has been implemented in civil engineering for efficiency & economic feasibility. National express no.600 of Pusan outer high-express ${\bigcirc}$ construction site with four lanes of the length of 8km was also a site applied by long hole blasting. But After blasting, tunnel advance rate is less than 75%. As a result of that, Follow-up working time is influenced. Thereby, The total of working process is significantly so increased that planned excavation cannot be implemented many times. For not only improve excavation rate but reduce working process time in job site, we introduce blasting case which apply the ${\phi}36mm$ explosive suited for high desity of charging among long hole blasting in order to overcome mentioned problem.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.726-729
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• 2010

Copper Pillar Tin Bump (CPTB) was investigated for high density chip interconnect technology development, which was prepared by electroplating and electro-less plating methods. Copper pillar tin bumps that have $100{\mu}m$ pitch were introduced with fabrication process using a KM-1250 dry film photoresist (DFR), with copper electroplating for Copper Pillar Bump (CPB) formation firstly, and then tin electro-less plating on it for control oxidation. Electric resistivity and mechanical shear strength measurements were introduced to characterize the oxidation effects and bonding process as a function of thermo-compression. Electrical resistivity increased with increasing oxidation thickness, and shear strength had maximum value with $330^{\circ}C$ and 500 N thermo-compression process. Through the simulation work, it was proved that when the CPTB decreased in its size, it was largely affected by the copper oxidation.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.644-651
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• 2011

This study presents a development of DeCatS(Detail Design of High Speed Catenary System) which is a software to design high speed catenary system automatically. The program is developed by Korea Railroad Research Institute with the support of KHSR. A process of developing it and a comparison with LEXCAT, in order to demonstrate a preciseness of that, were performed. In the program, decision of H-beam, cantilever fitting, management of materials, automatic drawing and etc. according to input conditions can be accomplished. In this study, especially the program algorithm for the decision of mast was introduced.

• 한국경영정보학회:학술대회논문집
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• 2008.06a
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• pp.270-275
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• 2008

The various research on Communities of practices (CoP) for propagation of softer type knowledge in new Knowledge Management (KM) strategy having been performed for past couple of years. CoP is one of effective process innovation tool for diffusion of knowledge. Based on CoP's voluntary and spontaneous characteristic, it performs a function of delivering softer type knowledge of workers to the other colleagues of organization. But one step further to CoP's function of propagation of internal knowledge, research on function of CoP's contribution in enterprise strategy are insufficient yet. This paper presents enterprise CoP should be managed and aligned to strategic objectives of enterprise, and also, suggests the methodology for CoPs to maintain a lifecycle as a tool to contribute in strategic goal attainment. Although CoPs are voluntary and spontaneous informal organization, it can display a contribution as tool for KM strategy when it is aligned to strategy properly and form efficient lifecycle.

• Knowledge Management Research
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• v.9 no.4
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• pp.157-178
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• 2008

It is well known in KM (Knowledge Management) literature that a certain amount of knowledge is necessary for KM to contribute to corporate performance to some extent. However, for a company to amass knowledge is very difficult due to limited time and poor understandings from employees. Especially, it becomes harder in public organization where simulating financial motif among members is constrained. In this respect, KORAIL, one of typical and leading public organizations in Korea, shows very unique example in which KORAIL succeeds in catalyzing the knowledge circulation process among members, string the resulted working knowledge, and then sharing it to improve working performance at an individual level as well as team level. This KORAIL case will help understand how important the knowledge circulation speed is to improving the corporate performance.

• Communications for Statistical Applications and Methods
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• v.22 no.1
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• pp.55-67
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• 2015

An important problem in cluster analysis is the selection of variables that define cluster structure that also eliminate noisy variables that mask cluster structure; in addition, outlier detection is a fundamental task for cluster analysis. Here we provide an automated K-means clustering process combined with variable selection and outlier identification. The Automated K-means clustering procedure consists of three processes: (i) automatically calculating the cluster number and initial cluster center whenever a new variable is added, (ii) identifying outliers for each cluster depending on used variables, (iii) selecting variables defining cluster structure in a forward manner. To select variables, we applied VS-KM (variable-selection heuristic for K-means clustering) procedure (Brusco and Cradit, 2001). To identify outliers, we used a hybrid approach combining a clustering based approach and distance based approach. Simulation results indicate that the proposed automated K-means clustering procedure is effective to select variables and identify outliers. The implemented R program can be obtained at http://www.knou.ac.kr/~sskim/SVOKmeans.r.

• Knowledge Management Research
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• v.11 no.2
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• pp.163-173
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• 2010

It is well known in KM (Knowledge Management) literature that a certain amount of knowledge is necessary for KM to contribute corporate performance to some extent. However, It is considerably difficult for a company to amass knowledge due to limited time and lack of understanding from employees. In this respect, DAEWOONG, one of leading pharmaceutical company in korea, shows very special knowledge management activity, SOP(Sucess of project), by which DAEWOONG succeeds in catalyzing the knowledge sharing process among members and cultivating men of ability. Also, DAEWOONG improve working performance at an individual level as well as team level. This case will help understand how important the knowledge management activity is to improve the corporate performance.

• Journal of the Korean Geographical Society
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• v.35 no.4
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• pp.641-647
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• 2000

한반도 중부지방의 사면형성과정을 검토하기 위하여 이 지역에 광범위하게 분포하는 쥬라기의 화강암과 선캄브리아기의 편마암으로 구성된 산지 소유역에서 수문관측을 실시하였다. 화강암 유역의 면적은 0.0546$\textrm{km}^2$이며, 기복비는 0.35이다. 편마암 유역은 다소 넓어 면적은 0.0754$\textrm{km}^2$이나 기복비는 0.36으로 거의 같다. 두 유역의 사면은 모두 사림으로 피복되어 있다. 관입시험 결과에 의하면 화강암유역 토층의 층후는 20cm 이하로 얇고 도처에 기반암이 보출된다. 반면에 편마암 유역의 층후는 50cm 이상으로 상대적으로 두껍게 나타난다. 관측은 1999년 5월부터 시작하였으며, 현재도 계속되고 있다. 강우에 대한 유출방응은 편마암 유역이 화강암 유역에 비하여 신속하게 나타난다. 첨두유량과 기저유량 모두 화강암유역보다는 편마암유역에 전반적으로 높게 관측되어 편마암 유역 사면에서의 저류량이 큰 것으로 생각된다. 또한 편마암사면에서 우수의 체류시간을 반영하여 전기전도도는 편마암 유역이 화강암유역보다 2배 정도 높게 관측된다.