• The KIPS Transactions:PartA
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• v.10A no.2
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• pp.157-164
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• 2003

Volume graphics have received a lot of attention as a medical image analysis tool nowadays. In the visualization based on volume graphics, there is a process called voxelization which transforms the geometrically defined objects into the volumetric objects. It enables us to volume render the geometrically defined data with sampling data. This paper suggests a voxeliration method using the cutting surfaces of cubes, implements the method on a PC, and evaluates it with simple geometric modeling data to explore propriety of the method. This method features the ability of calculating the exact normal vector from a voxel, having no hole among voxels, having multi-resolution representation.

• Geotechnical Engineering
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• v.14 no.3
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• pp.95-108
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• 1998

Downhole testing and seismic CPT (SCPT) have been widely used to evaluate stiffness profiles of the subgrade. Advantages of downhole testing and SCPT such as low cost, easy operation and a simple seismic source have got these testings more frequently adopted in site investigation. For the automated analysis of downhole testing and SCPT, the concept of interval measurements has been practiced. In this paper. a new inversion procedure to deal tilth the interval measurements for the automated downhole testing and SCPT (including a newlydeveloped continuous SCPT) is proposed. The forward modeling in the new inversion procedure incorporates ray path theory based on Snell's law. The formulation for the inversion analysis is derived from the maximum likelihood approach, which estimates the maximum likelihood of obtaining a particular travel time from a source to a receiver. Verification of the new inversion procedure was performed with numerical simulations of SCPT using synthesized profiles. The results of the inversion analyses performed for the synthetic data show that the new inversion analysis is a valid procedure which enhances Va profiles determined by downhole testing and SCPT.

• Journal of Korea Society of Industrial Information Systems
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• v.7 no.3
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• pp.43-53
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• 2002

The purpose of this study is to build a special -purpose browser using the powerful Microsoft web browser control so that we will be able to code and create a special-purpose browser. For this development, some literature surveys were reviewed to understand how the web browser looks like and is operated. To create our own web browser, we have designed a sample case and coded in Visual Basic. The primary task of this job was accomplished mainly with a form. It is made up with a bunch of image controls, a status bar on the button, a picture box to contain the image buttons, the combo box, the command button, the menus, the statements shown in the following exhibits and tables of the main text respectively. After combining them all together, we have tested the form to see if it works properly.'rho program was also enhanced to have a special purpose feature that permits the filtering function. The result was somewhat successful. However, it had some limitations such as the simplicity of the programming structures and functions. Overall, this study was useful for understand a general outline of special-purpose web browser development.

• Journal of the Korean Geotechnical Society
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• v.23 no.9
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• pp.29-37
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• 2007

The experiments have been conducted on Kaolinite in laboratory to investigate the development of shrinkage cracking and propose a simple model. Image analysis method consisting of control point selection(CPS) technique is used to process and analyze images of soil cracking captured by a digital camera. The distributions of crack length increment and crack area increment vary as a three-step process. These steps are regarded as stages of soil cracking. They are in turn primary crack, secondary crack and shrinkage crack stages. In case of crack area, the primary and secondary stages end at normalized gravimetric water content(NGWC) of 0.92 and 0.70 for different specimen thicknesses respectively. In addition, the primary stage in case of crack length also ends at NGWC of 0.92 while the secondary stage stops at NGWC of 0.79, 0.82, and 0.85 for the sample thicknesses of 0.5, 1.0, and 2.0 cm respectively Based on the experimental results, the distributions of crack length increment and crack area increment appear to be linear with a decrease of NGWC. Therefore, the development of shrinkage cracking is proposed typically by a simple model functioned by a combination of three linear expressions.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.87-97
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• 2008

The traditional trip-based modeling approach has assumed that a trip is generated for a purpose. However, the approach has not considered trips as a set of connected trips nor has it considered trip chaining. The purpose of this study is to identify general characteristics of trip chaining, and to explore relationships between trip purposes and trip chains using multivariate regression models. The data for this study come from the 2006 Seoul household travel diary survey. It is found that simple trip chains are dominant phenomena, and socio-economic characteristics such as occupation, income, age, and gender are closely related to types of trip chains. People aged less than 20, females, or high-income people are more likely to have a higher number of home-based trip chains. In addition, commute and school trips for workers and students respectively tend to be strongly associated with simple trip chains, while shopping and leisure trips for housewives tend to be related to simple trip chains.

• Journal of the Korea Concrete Institute
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• v.24 no.4
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• pp.481-490
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• 2012

Evaluation of chloride penetration is very important, because induced chloride ion causes corrosion in embedded steel. Diffusion coefficient obtained from rapid chloride penetration test is currently used, however this method cannot provide a correct prediction of chloride content since it shows only ion migration velocity in electrical field. Apparent diffusion coefficient of chloride ion based on simple Fick's Law can provide a total chloride penetration magnitude to engineers. This study proposes an analysis technique to predict chloride penetration using apparent diffusion coefficient of chloride ion from neural network (NN) algorithm and time-dependent diffusion phenomena. For this work, thirty mix proportions with the related diffusion coefficients are studied. The components of mix proportions such as w/b ratio, unit content of cement, slag, fly ash, silica fume, and fine/coarse aggregate are selected as neurons, then learning for apparent diffusion coefficient is trained. Considering time-dependent diffusion coefficient based on Fick's Law, the technique for chloride penetration analysis is proposed. The applicability of the technique is verified through test results from short, long term submerged test, and field investigations. The proposed technique can be improved through NN learning-training based on the acquisition of various mix proportions and the related diffusion coefficients of chloride ion.

• Journal of the Korean Geotechnical Society
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• v.23 no.12
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• pp.117-124
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• 2007

This study investigates the effect of spatial averaging and compliance taken account of in the analysis of earthquake-induced permanent deformation of slopes. At present, the rigid block analysis originally proposed by Newmark is widely used in the deformation analysis, mainly because of its computational efficiency. This type of approach, however, adopts the so-called decoupled approach, in which seismic response and deformation analyses are carried out separately. Original Newmark block analysis assumes the potential sliding mass to be noncompliant, and has been criticized to be potentially unconservative. This paper reviews the impact of the noncompliance assumption of the potential sliding mass in the Newmark-type analysis. The gross effects of earthquake shaking on the potential sliding mass are estimated by spatial averaging method and analyzed in frequency domain. The results indicate that there is a simple criterion that can be used to determine the level of compliance of the potential sliding mass.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.695-702
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• 2006

In GIS-based Spatial Decision-making Support System (SDSS), the Boolean logic by conventional simple overlay method contains two problems. One is losing lots of information in analysis process, the other is unable to reflect of weighting values between evaluated items. Therefore, evaluation system as Analytic Hierarchy Process (AHP) needs to improve these problems effectively. The purpose of this study is to provide the benefit of AHP method and GIS spatial analysis in site analysis for crop cultivation. First, the weighting value of AHP for topography, distribution grade of water, property of soil and slope items are evaluated throughout survey to experts of soil, crop and agricultural management fields. On the basis of these weighting value of AHP by items, site suitability analysis for black raspberry cultivation is performed. To estimate the benefit of AHP method, the current cultivating map of black raspberry is constructed in Ssangchi-myeon district. In comparison with site analysis of Boolean logic, site analysis of AHP method shows more realistic.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.189-192
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• 2010

분자 생물학을 통한 연구가 심화되면서, 생물학 정보는 기하급수적으로 늘어나고 있다. 그에 따라 바이오메디컬(생물학, 의학) 관련 논문들의 출판 및 등록 건수도 해마다 증가하고 있다. 그러나 바이오메디컬 문서들에서 유용한 정보를 추출하는 기술은 이러한 분야의 전문가 큐레이터(curator)에 의존한 경우가 많아서, 그 작업의 속도와 양적인 면에서 한계를 가지고 있다. 이러한 이유 때문에 바이오메디컬 문서를 기계학습을 통하여 분석하는 기법이 도입되기 시작하였다. 아직까지는 기계학습을 이용하여 구축된 데이터베이스가 소수에 불과하지만, 점차 증가하는 추세에 있다. 이러한 현 추이를 분석하고 향후의 추세를 예측하고자 텍스트마이닝 기술이 생물학과 의학 분야에서 어떻게 사용되며, 그 정보들이 어떻게 관리되는지 연구, 조사 하게 되었다. 현재 바이오메디컬 관련 데이터베이스들이 여러 기관 및 단체에 의해 구축 및 관리되고 있으며, 국가적인 프로젝트로서 이러한 데이터베이스들을 통합하는 과정을 진행하고 있다. 이처럼 국가기관의 주도하에 데이터베이스를 통합하여 관리하고자 하는 노력들이 계속되고 있어, 앞으로는 바이오메디컬 자료들을 검색하기가 보다 용이해질 것으로 생각된다. 텍스트마이닝을 이용하여 바이오메디컬 정보들을 추출하는 기술은 초기에는 공동 발생(co-occurence)과 같이 단순한 통계적 방법을 이용하였지만, 최근에는 다른 문서에서 추출된 정보와 기존의 정보들을 연계하여 새로운 정보를 추출해 내는 기법이 확산되고 있음을 알 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.184-184
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• 2020

수자원 계획 및 관리 시 증발산량의 정량적 분석은 필수적으로 고려되는 사항 중 하나이다. 일단위 이하의 잠재증발산량 산정은 세계식량기구(FAO)가 Penman-Monteith 방법을 기반으로 개발한 FAO56 PM 방법을 주로 활용하며, 이는 다른 방법에 비하여 높은 정확성과 적용성이 뛰어나다. 그러나 FAO56 PM 방법의 입력 매개변수는 다양한 기상자료이며, 장기간의 신뢰성 높은 자료를 구축하는 것은 어려운 실정이다. 이에 본 연구에서는 증발산량 공식인 Hargreaves 공식을 활용하여 FAO56 PM 방법으로 산정된 잠재증발산량과 기온차 사이의 시계열 관계를 재구성한 회귀분석 기법을 개발하였다. 개발된 모형에 유역면적을 적용하여 유역면적별 잠재증발산량을 산정하였으며, 이를 기존의 잠재증발산량과의 비교를 통해 모형의 적합성을 평가하였다. 결과적으로, 복잡한 잠재증발산량식을 단순한 대체모형(surrogate model)으로 제시함으로써 효율적인 증발산량 정량적 평가와 제한적인 기상자료 조건에 보편적 활용이 가능하다. 향후 연구에서는 회귀분석방법에 Bayesian 추론기법을 활용하여 구성함으로 잠재증발산량의 불확실성을 정량적으로 표현하고자 한다.