• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.198-207
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• 2010

Many methods and techniques have been developed to obtain the accurate design parameters in soft soils. In particular, several researchers suggest the techniques to get the void ratio for understanding the soil behavior. The objective of this paper verifies the accuracy of the proposed analytical solution for determining the void ratio based on the elastic wave velocities. The paper covers the theories of Wood, Biot, Gassmann and Foti proposed chronological order. The total theory represents the wave propagation in fully saturated medium. To verify the proposed analytical solution, the laboratory and field tests are carried out. After measuring the elastic wave, the void ratios are assessed using proposed equation. The volume based void ratios are also obtained for comparing with the estimated value by several equations. The values estimated by volume, Gassmann and Biot are show good similarity. However, the void ratios based on Wood and Foti methods have a slightly different trend. This study suggests that the theories of Biot and Gassmann may be a useful equation for assessing the void ratio using elastic wave velocities in the field.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.5
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• pp.477-486
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• 2008

Numerical analysis for slamming impact phenomena has been carried out when 2-dimensional wedge shaped structure with finite deadrise angles enter the free surface by using a commertial CFD code, FLUENT. Fluid is assumed incompressible and entry speed of the structure is kept constant. Geo-reconstruct scheme (or PLIC-VOF scheme) is used for the tracking of the deforming free surface. User defined function of 6 degrees of freedom motion and moving dynamic mesh option are used for the expression of the downward motion of the structure and deforming of unstructured meshes adjacent to the structure. The magnitude and the location of impact pressure and the total drag force which is the summation of pressures distributed at the bottom of the structure are analyzed. Results of the analysis show good agreement with the results of similarity solution, asymptotic solution and the solution of BEM.

• Structural Engineering and Mechanics
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• v.14 no.1
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• pp.99-118
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• 2002

The scaled-boundary finite element method is a novel semi-analytical technique, combining the advantages of the finite element and the boundary element methods with unique properties of its own. The method works by weakening the governing differential equations in one coordinate direction through the introduction of shape functions, then solving the weakened equations analytically in the other (radial) coordinate direction. These coordinate directions are defined by the geometry of the domain and a scaling centre. This paper presents a general development of the scaled boundary finite-element method for two-dimensional problems where two boundaries of the solution domain are similar. Unlike three-dimensional and axisymmetric problems of the same type, the use of logarithmic solutions of the weakened differential equations is found to be necessary. The accuracy and efficiency of the procedure is demonstrated through two examples. The first of these examples uses the standard finite element method to provide a comparable solution, while the second combines both solution techniques in a single analysis. One significant application of the new technique is the generation of transition super-elements requiring few degrees of freedom that can connect two regions of vastly different levels of discretisation.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.642-642
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• 2015

최근 지속가능한 개발을 위한 연구와 수자원 취약성에 대한 논의가 활발히 이루어지는 가운데, 북한의 수자원에 대한 관심 또한 증가하여 다방면으로 연구가 진행되고 있다. 본 연구는 북한 자료의 확보가 가능한 World Bank 자료를 바탕으로 Pressure-State-Response 구조에 따라 선정된 14개의 지표를 이용하여 168개 국가를 대상으로 수자원 취약성 분석을 수행하였다. 의사결정을 위한 가중치 결정은 객관적 가중치 산정방법인 Shannon의 entropy 기법을 이용하였으며, 정량적 평가를 위하여 TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) 기법을 적용하여 국가 별 수자원 취약성을 지수화하고 취약성 순위를 도출하였다. 각 지표별 Positive Ideal Solution과 Negative Ideal Solution의 거리를 산정한 후 상대근접도계수를 산정하였으며, 상대근접도계수가 작은 국가일수록 수자원이 취약한 국가가 된다. 연구결과 북한은 168개 국가 중 17위, 우리나라는 67위로 나타났으며, 대체적으로 남 북한의 수자원 취약성이 취약한 가운데 북한이 더 취약한 것으로 나타났다. 우리나라와 연관이 깊은 주요 국가와 비교 시, 북한, 중국, 미국, 일본, 우리나라 순으로 취약성의 정도가 심각했다. 또한, 압력, 상태, 반응의 요소별로 수자원 취약성을 분석한 결과 북한이 반응요소 측면에서 타 국가에 비해 불안정하였으며, 우리나라의 경우 상태요소 측면에서 취약함을 보였다. 따라서 본 연구는 국가 간 우리나라와 북한의 상황을 파악할 수 있게 해주며, 수자원 취약성 극복을 위한 수자원 계획 및 대책을 제시할 수 있는 자료로 활용할 수 있을 것이다.

• Computers and Concrete
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• v.32 no.4
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• pp.399-410
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• 2023

This study proposes a novel use of backpropagated Levenberg-Marquardt neural networks based on computational intelligence heuristics to comprehend the examination of hybrid nanoparticles on the flow of dusty liquid via stretched cylinder. A two-phase model is employed in the present work to describe the fluid flow. The use of desulphated nanoparticles of silver and molybdenum suspended in water as base fluid. The mathematical model represented in terms of partial differential equations, Implementing similarity transformationsis model is converted to ordinary differential equations for the analysis . By adjusting the particle mass concentration and curvature parameter, a unique technique is utilized to generate a dataset for the proposed Levenberg-Marquardt neural networks in various nanoparticle circumstances on the flow of dusty liquid via stretched cylinder. The intelligent solver Levenberg-Marquardt neural networks is trained, tested and verified to identify the nanoparticles on the flow of dusty liquid solution for various situations. The Levenberg-Marquardt neural networks approach is applied for the solution of the hybrid nanoparticles on the flow of dusty liquid via stretched cylinder model. It is validated by comparison with the standard solution, regression analysis, histograms, and absolute error analysis. Strong agreement between proposed results and reference solutions as well as accuracy provide an evidence of the framework's validity.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.206-211
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• 2006

The quantification analysis problem is that how the m entities that have n characteristics can be linked to p-dimension space to reflect the similarity of each entity In this paper, the optimization approach for the quantification analysis problem using neural networks is suggested, and the performance is analyzed The computation of average variation volume by mean field theory that is analytical approximated mobility of a molecule system and the annealed mean field neural network approach are applied in this paper for solving the quantification analysis problem. As a result, the suggested approach by a mean field annealing neural network can obtain more optimal solution than the eigen value analysis approach in processing costs.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.245-250
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• 2007

We have proposed Fuzzy-CBR to find a solution from past knowledge retrieved from the database and adapted to a new situation. However, ontology is needed in identifying concepts, relations and instances that are involved in a situation in order to improve and facilitate the efficient retrieval of similar cases from the CBR database. This paper proposes the way to apply ontology fur identifying the concepts involved in a new case, used as inputs, for a ship collision avoidance support system and in solving for similarity through document articulation and abstraction levels. These ontologies will be used to build a conceptual model of a maneuvering situation.

• Korean Institute of Interior Design Journal
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• v.16 no.2 s.61
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• pp.63-70
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• 2007

Analogy in problem solving is similarity-based reasoning facilitated by verbal and visual operation. This similarity-based reasoning generally supports initial phase of idea search. Therefore, this study intends to infer the types of problem solving by tracing the analogy use of verbal and visual representation through a experimental research. According to the result of this research, the types of problem solving by analogy are classified into 'evolving', 'divergent', and 'poor conversion' type. Firstly, 'evolving type' is distinguished between 'combination type' associated different contents to develope a new design and 'transformation type' associated similar words and sketches to be continuously revised and developed. In these types usually structural analogy rather than surface analogy is used. Secondly, in 'divergent type' associated words or sketches are individually represented, and among them one design solution is selected. In this type usually surface analogy is used. Thirdly, in 'poor conversion type' interaction between verbal representation and visual representation does not go on smoothly, and the generation of idea is poor. In here surface analogy is mostly used. These findings could form the basis of skill development of idea generation and conversion in design education.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.1
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• pp.257-271
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• 2016

The Structural SIMilarity (SSIM) index is one of the most widely-used methods for perceptual image quality assessment (IQA). It is based on the principle that the human visual system (HVS) is sensitive to the overall structure of an image. However, it has been reported that indices predicted by SSIM tend to be biased depending on the type of distortion, which increases the deviation from the main regression curve. Consequently, SSIM can result in serious performance degradation. In this study, we investigate the aforementioned phenomenon from a new perspective and review a constant that plays a big role within the SSIM metric but has been overlooked thus far. Through an experimental study on the influence of this constant in evaluating images with SSIM, we are able to propose a new solution that resolves this issue. In the proposed IQA method, we first design a system to classify different types of distortion, and then match an optimal constant to each type. In addition, we supplement the proposed method by adding color perception-based structural information. For a comprehensive assessment, we compare the proposed method with 15 existing IQA methods. The experimental results show that the proposed method is more consistent with the HVS than the other methods.

• The Journal of Industrial Distribution & Business
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• v.7 no.1
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• pp.5-10
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• 2016

Purpose - The purpose of this research is to suggest researchers to know the standards of research ethics violation and eliminate the researchers' anxiety for the possible cases in violation of research ethics through the notification on the web site with online paper submission system for over the last year. We have made an effort and achieved the most exemplary and leading position in the academic journals, however, not satisfied with this, we will endeavor to strengthen it. Research design, data and methodology - Plagiarism and overlapping publications are the most serious problems in research ethics. Therefore, it is necessary to verify the submitted articles making use of paper similarity test programs such as copy killer, KCI test, etc. Editorial board and reviewers should present clear evidences and notify contributors on research ethics violation after close review the contributors' article content. Results - This research focused on the submitted articles which were verified as research ethics violation, and categorized them into 7 cases. Conclusions - With analyzing the verified 7 cases from KODISA journals, this research will examine closely the verification system and regulations in the current academic research ethics. Afterwards, this research will seek for solution to the problems and make an effort to get improvement for them.