• Journal of Information Processing Systems
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• v.11 no.1
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• pp.1-21
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• 2015

This paper aims to assess the feasibility of a new and less-focused type of online sociability (the watching network) as a useful information source for personalized recommendations. In this paper, we recommend scientific articles of interests by using the shared interests between target users and their watching connections. Our recommendations are based on one typical social bookmarking system, CiteULike. The watching network-based recommendations, which use a much smaller size of user data, produces suggestions that are as good as the conventional Collaborative Filtering technique. The results demonstrate that the watching network is a useful information source and a feasible foundation for information personalization. Furthermore, the watching network is substitutable for anonymous peers of the Collaborative Filtering recommendations. This study shows the expandability of social network-based recommendations to the new type of online social networks.

• Journal of Environmental Impact Assessment
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• v.18 no.6
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• pp.445-452
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• 2009

This study surveys the surface water environment in Southwest sea areas of Vietnam in order to evaluate the current environment. It collects and analyzes experimental results of programs, scientific subjects, and international projects relevant to ecological areas and coastlines of Kien Giang province. The methods analyzed and discussed by specialists are evaluated according to pollution coefficients established by the World Health Organization (WHO), sampling methods, and case study analyses. Comparison between the scale of pollution levels and the surface water quality in experimental areas of Long Xuyen Quadrangle shows a light-moderate pollution level. In Ca Mau Peninsula, the surface water source is only slightly polluted. Sea areas and islands are also light-moderately polluted. Computing results from water quality indices (WQI) show the level of pollution in experimental sites. Activities such as constructing infrastructures for tourism, exploiting minerals, and increasing population accelerate environmental pollution by deteriorating inherently sensitive ecosystems like corals, sea grass, mangrove swamps, and Melaleuca forests. Surveying and evaluating the present situation of surface water are fundamental solutions for environmental protection in the Southwest sea areas of Vietnam.

• ETRI Journal
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• v.35 no.2
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• pp.218-225
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• 2013

The pull-out frequency of a second-order phase lock loop (PLL) is an important parameter that quantifies the loop's ability to stay frequency locked under abrupt changes in the reference input frequency. In most cases, this must be determined numerically or approximated using asymptotic techniques, both of which require special knowledge, skills, and tools. An approximating formula is derived analytically for computing the pull-out frequency for a second-order Type II PLL that employs a sinusoidal characteristic phase detector. The pull-out frequency of such PLLs can be easily approximated to satisfactory accuracy with this formula using a modern scientific calculator.

• Journal of applied mathematics & informatics
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• v.11 no.1_2
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• pp.59-80
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• 2003

An incomplete factorization method for preconditioning symmetric positive definite matrices is introduced to solve normal equations. The normal equations are form to solve linear least squares problems. The procedure is based on a block incomplete Cholesky factorization and a multilevel recursive strategy with an approximate Schur complement matrix formed implicitly. A diagonal perturbation strategy is implemented to enhance factorization robustness. The factors obtained are used as a preconditioner for the conjugate gradient method. Numerical experiments are used to show the robustness and efficiency of this preconditioning technique, and to compare it with two other preconditioners.

• Computers and Concrete
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• v.15 no.3
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• pp.337-355
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• 2015

In this scientific work, an improved analytical solution for adhesive stresses in a concrete beam bonded with the FRP plate is developed by including the effect of the adherend shear deformations. The analysis is based on the deformation compatibility approach where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. The shear stress distribution is supposed to be parabolic across the depth of the adherends in computing the adhesive shear stress and Timoshenko's beam theory is employed in predicting adhesive normal stress to consider the shear deformation. Numerical results from the present analysis are presented both to demonstrate the advantages of the present solution over existing ones and to illustrate the main characteristics of adhesive stress distributions.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06c
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• pp.160-162
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• 2012

본 논문에서는 논문들 간의 유사도를 계산하는 기존 링크 기반 유사도 계산 방안의 정확도를 향상시키기는 방안을 제안한다. 제안하는 방안은 링크로 연결되어 있는 두 객체의 관련 정도를 경험적인 세 가지 방법(인기도 고려, 발행연도 고려, 내용 관련도 고려)을 이용해서 계산하고 계산된 값을 링크의 가중치로 사용한다. 실험을 통하여 기존 링크 기반 유사도 계산 방안보다 제안하는 방안을 적용한 기존 링크 기반 유사도 계산 방안의 정확도가 우수하다는 것을 보인다.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.729-736
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• 2008

Using video synthesis to depict flowing water is useful in virtual reality, computer games, digital movies and scientific computing. This paper presents a novel algorithm for synthesizing dynamic water scenes through a sample video based on a dynamic texture model. In the paper, we treat the video sample as a 2-D texture image. In order to obtain textons, we analyze the video sample automatically based on dynamic texture model. Then, we utilize a linear dynamic system (LDS) to describe the characteristics of each texton. Using these textons, we synthesize a new video for dynamic flowing water which is prolonged and non-fuzzy in vision. Compared with other classical methods, our method was tested to demonstrate the effectiveness and efficiency with several video samples.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.902-903
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• 2009

Matrix multiplication is widely used in scientific and engineering field. Locality can improve the execution performance of matrix multiplication. A method for accelerating matrix multiplication is presented. This method uses both CPU and GPU computing power in PC. The presented method improved execution time about %15~30% than the method which uses only GPU.

• Coupled systems mechanics
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• v.11 no.5
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• pp.411-438
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• 2022

In this paper, we present the parameter identification for inelastic and multi-scale problems. First, the theoretical background of several fundamental methods used in the upscaling process is reviewed. Several key definitions including random field, Bayesian theorem, Polynomial chaos expansion (PCE), and Gauss-Markov-Kalman filter are briefly summarized. An illustrative example is given to assimilate fracture energy in a simple inelastic problem with linear hardening and softening phases. Second, the parameter identification using the Gauss-Markov-Kalman filter is employed for a multi-scale problem to identify bulk and shear moduli and other material properties in a macro-scale with the data from a micro-scale as quantities of interest (QoI). The problem can also be viewed as upscaling homogenization.

• East Asian mathematical journal
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• v.39 no.4
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• pp.479-492
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• 2023

Although Euclidean plane geometry is implemented in the middle school course, there are three major problems in high school space geometry that can be intuitively taken for granted or misinterpreted as circular arguments. In order to solve this problem, this study proved three major problems using sets, Euclidean plane geometry, and parallel line postulates. This corresponds to a logical sequence and has mathematical and mathematical educational values. Furthermore, it will be possible to configure spatial geometry using sets, and by giving legitimacy to non-Euclidean spatial geometry, it will open the possibility of future research.