• Journal of the Korean Geotechnical Society
• /
• v.31 no.1
• /
• pp.47-52
• /
• 2015

In the slope stability analysis and design, Limit Equilibrium Method (LEM) and Shear Strength Reduction technique (SSR) are mainly used. Both methods are able to perform two and three dimensional analysis. SSR is considered to be more sensitive and more reasonable than LEM by many researchers. However, in practice LEM is still widely used because of the increase of analysis time and complexity of the model in SSR. In this study, three dimensional analysis of the protruding rock slope is performed by SSR in order to study the effects of protruding length using rock slope FLAC 3D. In this study, as results of analysis variations of the safety factor have been studied according to slope angle, slope height, the soil strength, protruding slope length projected variables. The results show that the factor of safety as more affected by the shapes of the protruding rock slope than the rock strength.

• Journal of Ocean Engineering and Technology
• /
• v.21 no.2 s.75
• /
• pp.12-21
• /
• 2007

As the economy grows and the population increases, we need to develop our coastal area and make use of it for various purposes. Specifically, investigation of the wave interactions on and around the vertical cylinders is very important in the design of the offshore or coastal structures. The nonlinear potential analysis developed so far, although very useful, has been found to be limited in application, as strong nonlinear waves generated by the interference between multilayered cylinders and wave impact forces by breaking waves can hardly be estimated. In this study, using a 3-Dimensional volume tracking method VOF(Volume of Fluid), based on Namer-Stokes equations, was developed to simulate highly nonlinear effects, such as breaking waves at the interface or complicated interference waves among structures. A numerical method for nonlinear interaction wave and vertical cylinders is newly proposed. The wave forces and wave transformations computed by the newly proposed numerical simulation method were compared to the other researcher's experimental results, and the results agree well. Based on the validation of this study, this numerical method is applied to the two vertical cylinders to discuss their nonlinear wave forces and wave transformations, according to the variations of separate distance of vertical cylinders.

• Journal of Electrical Engineering and Technology
• /
• v.12 no.6
• /
• pp.2388-2398
• /
• 2017

In this study, we propose a robust face recognition system to pose variations based on automatic pose estimation. Radial basis function neural network is applied as one of the functional components of the overall face recognition system. The proposed system consists of preprocessing and recognition modules to provide a solution to pose variation and high-dimensional pattern recognition problems. In the preprocessing part, principal component analysis (PCA) and 2-dimensional 2-directional PCA ($(2D)^2$ PCA) are applied. These functional modules are useful in reducing dimensionality of the feature space. The proposed RBFNNs architecture consists of three functional modules such as condition, conclusion and inference phase realized in terms of fuzzy "if-then" rules. In the condition phase of fuzzy rules, the input space is partitioned with the use of fuzzy clustering realized by the Fuzzy C-Means (FCM) algorithm. In conclusion phase of rules, the connections (weights) are realized through four types of polynomials such as constant, linear, quadratic and modified quadratic. The coefficients of the RBFNNs model are obtained by fuzzy inference method constituting the inference phase of fuzzy rules. The essential design parameters (such as the number of nodes, and fuzzification coefficient) of the networks are optimized with the aid of Particle Swarm Optimization (PSO). Experimental results completed on standard face database -Honda/UCSD, Cambridge Head pose, and IC&CI databases demonstrate the effectiveness and efficiency of face recognition system compared with other studies.

• Journal of Astronomy and Space Sciences
• /
• v.31 no.4
• /
• pp.303-309
• /
• 2014

The Earth's outer radiation belt often suffers from drastic changes in the electron fluxes. Since the electrons can be a potential threat to satellites, efforts have long been made to model and predict electron flux variations. In this paper, we describe a prediction model for the outer belt electrons that we have recently developed at Chungbuk National University. The model is based on a one-dimensional radial diffusion equation with observationally determined specifications of a few major ingredients in the following way. First, the boundary condition of the outer edge of the outer belt is specified by empirical functions that we determine using the THEMIS satellite observations of energetic electrons near the boundary. Second, the plasmapause locations are specified by empirical functions that we determine using the electron density data of THEMIS. Third, the model incorporates the local acceleration effect by chorus waves into the one-dimensional radial diffusion equation. We determine this chorus acceleration effect by first obtaining an empirical formula of chorus intensity as a function of drift shell parameter $L^*$, incorporating it as a source term in the one-dimensional diffusion equation, and lastly calibrating the term to best agree with observations of a certain interval. We present a comparison of the model run results with and without the chorus acceleration effect, demonstrating that the chorus effect has been incorporated into the model to a reasonable degree.

• Journal of Korean Society for Atmospheric Environment
• /
• v.24 no.4
• /
• pp.423-438
• /
• 2008

BEIS2 (Biogenic Emissions Inventory System version 2) and BEIS3.12 (BEIS version 3.12) were used to estimate hourly biogenic emissions over South Korea using a set of vegetation and meteorological data simulated with the MM5 (Mesoscale Model version 5). Two biogenic emission models utilized different emission factors and showed different responses to solar radiations, resulting in about $10{\sim}20%$ difference in the nationwide isoprene emission estimates. Among the 11-vegetation classes, it was found that mixed forest and deciduous forest are the most important vegetation classes producing isoprene emissions over South Korea comprising ${\sim}90%$ of the total. The simulated isoprene concentrations over Seoul metropolitan area show that diurnal and daily variations match relatively well with the PAMS (Photochemical Air Monitoring Station) measurements during the period of June 3${\sim}$June 10, 2004. Compared to BEIS2, BEIS3.12 yielded ${\sim}35%$ higher isoprene concentrations during daytime and presented better matches to the high peaks observed over the Seoul area. This study showed that the importance of vegetation data and emission factors to estimate biogenic emissions. Thus, it is expected to improve domestic vegetation categories and emission factors in order to better represent biogenic emissions over South Korea.

• Korean Journal of Cognitive Science
• /
• v.13 no.3
• /
• pp.11-21
• /
• 2002

Parke and Waters' model［1］ of muscle-based face deformation was used to develop a system that can synthesize facial expressions when the pleasure-displeasure and arousal-sleep coordinate values of internal states are specified. Facial expressions sampled from a database developed by Chung, Oh, Lee and Byun ［2］ and its underlying model of internal states were used to find rules for face deformation. The internal - state model included dimensional and categorical values of the sampled facial expressions. To find out deformation rules for each of the expressions, changes in the lengths of 21 facial muscles were measured. Then, a set of multiple regression analyses was performed to find out the relationship between the muscle lengths and internal states. The deformation rules obtained from the process turned out to produce natural-looking expressions when the internal states were specified by the pleasure-displeasure and arousal-sleep coordinate values. Such a result implies that the rules derived from a large scale database and regression analyses capturing the variations of individual muscles can be served as a useful and powerful tool for synthesizing facial expressions.

• The Journal of the Korea Contents Association
• /
• v.13 no.10
• /
• pp.419-426
• /
• 2013

This study investigates the usefulness of body fix in 4DRT on Liver cancer trying to find tumor tissue's volume and located variations, absorbed dose on tumor and normal tissues. Test subjects 23 patients were agreed these test. These patient's have a 4 dimensional CT scan. We make an acquisition on patients CT image by two types -put on the body fix or not-. Average tumor volume reduced by 0.17% on GTV and 3.2% on CTV and PTV. Tumor's variation reduces 29.8%(anterior and posterior, AP) and 5.31% (upper and lower, UL). The absorbed tumor doses under put on the body fix was a little higher(1.3%) than other. Normal tissues'(normal liver, stomach, Rt. kidney, spinal cord) absorbed dose could be reduced approximately 5%. Therefore, using body fix on 4DRT for liver cancer patient is considered effectively.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.22 no.1
• /
• pp.75-87
• /
• 2006

The purpose of this study was to investigate the effects of prostheses misfit, cantilever on the stress distribution in the implant components and surrounding bone using three dimensional finite element analysis. Two standard 3-dimensional finite element models were constructed: (1) 3 ITI implant supported, 3-unit fixed partial denture and (2) 3 ITI implant supported, 3-unit fixed partial denture with a distal cantilever. variations of the standard finite element models were made by placing a $100{\mu}m$ or $200{\mu}m$ gap between the fixture, the abutment and the crown on the second premolar and first molar. Total 14 models were constructed. In each model, 244 N of vertical load and 244 N of $30^{\circ}$ oblique load were placed on the distal marginal ridge of the distal molar. von Mises stresses were recorded and compared in the crowns, abutments, crestal compact bones, and trabecular bones. The results were obtained as follows: 1. In the ITI implant system, cement-retained prostheses showed comparatively low stress distributions on all the implant components and fixtures regardless of the misfit sizes under vertical loading. The stresses were increased twice under oblique loading especially in the prostheses with cantilever, but neither showed the effects of misfit size. 2. Under the oblique loading and posterior cantilever, the stresses were highly increased in the crestal bones around ITI implants, but effects of misfit were not shown. Although higher stresses were shown on the apical portion of trabecular bones, the effects by misfit were little and the stresses were increased by the posterior cantilever. 3. When the cement loss happened in the ITI implant supported FPD with misfit, the stresses were increased in the implant componets and supporting structures.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.6 no.3
• /
• pp.21-32
• /
• 2003

This paper discusses the design of location optimization visualization and feasibility of 3 dimensional visualization techniques. In generic GIS visualization of location analysis, 2 dimensional visualization techniques have been used to map location elements and model solution, such as displaying demand and supply points, drawing connecting lines(e. g. spider line) of optimal locations to their demands, and representing density of location variations. Nevertheless, current GIS and location analysis literatures have little attentions in 3D visualization applications for location optimization problems. Previous research has been neglected 3D visualization of solution performances and its evaluation of solution quality. Consequently, this paper demonstrates potential benefits of 3D visualization techniques and its appropriate GIS applications for location optimization analysis. The visualization effectiveness of 3D approaches is examined in terms of spatial accessibility, and solution performance of optimal location models is evaluated. Finally, this paper proposes extensive 3D visualization perspectives for location analysis and GIS research as a further research agenda.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.15 no.3
• /
• pp.399-407
• /
• 2002

A three-dimensional method of analysis is presented for determining the free vibration frequencies and mode shapes of hollow bodies of revolution (i.e., thick shells), not limited to straight line generators or constant thickness. The middle surface of the shell may have arbitrary curvatures, and the wall thickness may vary arbitrarily. Displacement components$U_\Phi, U_z, U_\theta$ in the meridional, normal and circumferential directions, respectively, are taken to be sinusoidal in time, periodic in$\theta$, and algebraic polynomials in the$\Phi$and z directions. Potential(strain) and kinetic energies of the entire body are formulated, and upper bound values of the frequencies are obtained by minimizing the frequencies. As the degrees of the polynomials are increased, frequencies converge to the exact values. Novel numerical results are presented for two types of thick conical shells and thick spherical shell segments having linear thickness variations. Convergence to four digit exactitude is demonstrated for the first five frequencies of both types of shells. The method is applicable to thin shells, as well as thick and very thick ones.