• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 가을 학술발표회 논문집
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• pp.421-428
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• 2004

Various type of welded joints of the ship structure have been examined numerically and experimentally under bending and tensional cyclic constant-amplitude loading. Cyclic loading on structures can produce failures not readily predicted by conventional static analysis. The aim of a benchmark study is achieved with a generalization of the reference stress concept. Also different methods and procedures exist for the computation of the welded structure hot-spot stress a welded joints. These are either based on the extrapolation of stresses at certain reference points on the plate surface (or edge) close to the weld toe-as known from experimental investigations- or on the linearization of stresses in the through-thickness direction. In the present paper, the different methods are reviewed and applied to four different details in order to compare the methods with each other and to illustrate the differences.

• 대한조선학회논문집
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• 제47권5호
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• pp.657-669
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• 2010

Cavitation is one of the most difficult physical phenomena to understand and predict. Many experimental and computational studies have been conducted for better understanding of the phenomenon. Recently, with the rapid development of computing hardware capacity and numerical methods, considerable advancement is observed in prediction of cavitation using computational fluid dynamics. To that end, many cavitation models have been developed and reported. In the present paper, some of the distinguished cavitation models are categorized and reviewed in terms of the computational frame work and formulation of transport equations. Then those characteristics are compared with each other.

• Advances in Computational Design
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• 제5권3호
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• pp.323-347
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• 2020

The enhancements of bioenergy production effectiveness require the comprehensively experimental study of several parameters affecting these bioprocesses. The interpretation of the obtained experimental results and the estimation of optimum yield are extremely complicated such as misinterpreting the results of an experiment. The use of mathematical modeling and statistical experimental designs can consistently supply the predictions of the potential yield and the identification of defining parameters and also the understanding of key relationships between factors and responses. This paper summarizes several mathematical models used to achieve an adequate overall and maximal production yield and rate, to screen, to optimize, to identify, to describe and to provide useful information for the effect of several factors on bioenergy production processes. The usefulness, the validity and, the feasibility of each strategy for studying and optimizing the bioenergy-producing processes were discussed and confirmed by the good correlation between predicted and measured values.

• 한국CDE학회논문집
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• 제14권6호
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• pp.404-414
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• 2009

In the computational molecular analysis, 3D structural comparison for protein searching plays a very important role. As protein databases have been grown rapidly in size, exhaustive search methods cannot provide satisfactory performance. Because exhaustive search methods try to handle the structure of protein by using sphere set which is converted from atoms set, the similarity calculation about two sphere sets is very expensive. Instead, the filter-and-refine paradigm offers an efficient alternative to database search without compromising the accuracy of the answers. In recent, a very fast algorithm based on the inter-atomic distance has been suggested by Ballester and Richard. Since they adopted the moments of distribution with inter-atomic distance between atoms which are rotational invariant, they can eliminate the structure alignment and orientation fix process and perform the searching faster than previous methods. In this paper, we propose a new 3D shape descriptor. It has properties of the general shape distribution and useful property in screening the molecular database. We show some experimental results for the validity of our method.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2012년도 춘계학술발표대회논문집
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• pp.6-9
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• 2012

In this study, we compare two image denoising methods which are the Rudin-Osher-Fatemi total variation (TV) model and the nonlocal means (NLM) algorithm on medical images. To evaluate those methods, we used two well known measuring metrics. The methods are tested with a CT image, one X-Ray image, and three MRI images. Experimental result shows that the NML algorithm can give better results than the ROF TV model, but computational complexity is high.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1310-1319
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• 2016

Face detection is the first step in a wide range of face applications. However, detecting faces in the wild is still a challenging task due to the wide range of variations in pose, scale, and occlusions. Recently, many deep learning methods have been proposed for face detection. However, further improvements are required in the wild. Another important issue to be considered in the face detection is the computational complexity. Current state-of-the-art deep learning methods require a large number of patches to deal with varying scales and the arbitrary image sizes, which result in an increased computational complexity. To reduce the complexity while achieving better detection accuracy, we propose a fully convolutional network-based face detection that can take arbitrarily-sized input and produce feature maps (heat maps) corresponding to the input image size. To deal with the various face scales, a multi-scale network architecture that utilizes the facial components when learning the feature maps is proposed. On top of it, we design multi-task learning technique to improve detection performance. Extensive experiments have been conducted on the FDDB dataset. The experimental results show that the proposed method outperforms state-of-the-art methods with the accuracy of 82.33% at 517 false alarms, while improving computational efficiency significantly.

• 공학교육연구
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• 제17권6호
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• pp.62-68
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• 2014

The purpose of this work is to provide systematic lecture materials for instructers who search for the effective teaching of applied mechanics of materials course with respect to lecture contents, teaching methods, and itemized course evaluations according to each class learning objective. For this. the evolution of teaching contents since 2010 until 2014 are briefly depicted and then most recent course learning objectives, lecture contents, and evaluation schemes are presented in detail. The results of this study may be used as base line data for the lecturers who teach similar courses and for the evaluation of program outcomes in ABEEK scheme through course-embedded assessment.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1989년도 봄 학술발표회 논문집
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• pp.44-49
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• 1989

The primary purpose of using bracings is to improve tile lateral rigidity of main structural system, i.e., columns and beams, by reinforcing them with much smaller members. Conventional design methods consider bracings as tension-only mambers, since difficulties arise in the analysis to consider the P - effects and post-buckling behaviour of the bracing members. This is particulary true for X-bracings. Recently, however, both analytical and experimental studies have been conducted to investigate the more precise and real behaviour of bracing members, especially for the nonlinear un plastic behaviour under cyclic loads. In this study, an analytical model is proposed to investigate the nonlinear behavior of steel bracing members subjected to cyclic loads. Results of tile analysis were compared with previous experimental results, and good agreements were obtained between these results.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2003년도 The Fifth Asian Computational Fluid Dynamics Conference
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• pp.255-256
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• 2003

Simulations of atmospheric diffusion process under stable and unstable conditions were carried out using both numerical and experimental methods. Results from the previous study show that numerical simulation using 3-dimensional incompressible Navier-Stokes equation and density deviation are in good agreement with typical plume pattern. In this study, we use experimental data of temperature and wind profile obtained from a thermally stratified wind tunnel as initial conditions for numerical simulation and compare the results.

• 한국광물학회지
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• 제27권4호
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• pp.271-281
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• 2014

점토광물의 물리화학적 특성에 대한 분자 또는 원자 스케일의 연구 중요성이 강조되고 있다. 그러나 실험만으로는 광물의 미시적 현상을 이해하기 어려운 경우가 많다. 특히 2:1 점토광물 팔면체에 존재하는 수산기(hydroxyl)가 금속 양이온 흡착과정에 큰 역할을 한다는 가정은 X-ray를 이용하는 실험만으로는 명확하게 테스트하기 어렵다. 이번 논문에서는 점토광물 내의 수산기 연구에 대한 전산광물학(computational mineralogy) 이용 가능성에 대하여 조사하였다. 점토광물의 기본구조인 팔면체 층만으로 구성된 광물, 1:1 구조를 갖는 광물, 2:1 구조를 갖는 광물 중 대표적인 이팔면체 및 삼팔면체 층상규산염 광물을 선별하여 구조최적화를 실시하였다. 분자역학적(molecular mechanics) 계산과 양자역학적(quantum mechanical) 계산 모두 실험값의 격자상수(lattice parameters)를 잘 재현할 수 있었다. 그러나, 사면체층과 팔면체의 구조적 뒤틀림(structural distortion) 등 광물 내부구조를 기존 실험결과와 비교했을 때, 양자역학적 계산결과가 분자역학적 방법을 이용한 결과 보다 더 낮은 오차를 보였다. 파이로필라이트(pyrophyllite) 수산기가 (001)면과 이루는 각은, 수산기의 H(proton)과 사면체의 Si 양이온 간의 척력으로 결정되는데, 양자역학적 방법은 약 $25-26^{\circ}$로 예측하였고, 분자역학적 방법은 약 $35^{\circ}$ 정도로 양자역학계산 결과와 무려 $10^{\circ}$의 큰 차이를 보였다. 전산광물학은 점토광물 구조연구에 신뢰성이 매우 높은 연구방법으로 양이온 흡착과정 중 수산기의 역할 규명에 사용될 수 있다.