• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2851-2865
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• 2014

To improve the rate-distortion performance of distributed video compressive sensing (DVCS), the adaptive sparse basis and nonlocal similarity of video are proposed to jointly reconstruct the video signal in this paper. Due to the lack of motion information between frames and the appearance of some noises in the reference frames, the sparse dictionary, which is constructed using the examples directly extracted from the reference frames, has already not better obtained the sparse representation of the interpolated block. This paper proposes a method to construct the sparse dictionary. Firstly, the example-based data matrix is constructed by using the motion information between frames, and then the principle components analysis (PCA) is used to compute some significant principle components of data matrix. Finally, the sparse dictionary is constructed by these significant principle components. The merit of the proposed sparse dictionary is that it can not only adaptively change in terms of the spatial-temporal characteristics, but also has ability to suppress noises. Besides, considering that the sparse priors cannot preserve the edges and textures of video frames well, the nonlocal similarity regularization term has also been introduced into reconstruction model. Experimental results show that the proposed algorithm can improve the objective and subjective quality of video frame, and achieve the better rate-distortion performance of DVCS system at the cost of a certain computational complexity.

• International Journal of Highway Engineering
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• v.19 no.4
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• pp.37-44
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• 2017

PURPOSES : Conductive and convective heat transfer simulations for an asphalt mixture were made by using discrete element method (DEM) and similarity principle. METHODS : In this research, virtual specimens composed of discrete element method particles were generated according to four different predetermined particle size distribution curves. Temperature variations of the four different particles for a given condition were estimated and were compared with measurements and analytical solutions. RESULTS : The virtual specimen with mixed particles and with the smallest particle show very good agreement with laboratory test results and analytical solutions. As particle size decreases, better heat transfer simulation can be performed due to smaller void ratio and more contact points and areas. In addition, by utilizing the similarity principle of thermal properties and corresponding time unit, analytical time can be drastically reduced. CONCLUSIONS : It is concluded that the DEM asphalt mixture specimens with similarity principle could be used to predict the temperature variation for a given condition. It is observed that the void ratio has critical effect on prediction of temperature variation. Comparing the prediction for a 4 mm particle specimen with a mixed particle specimen, it is also concluded that predicting the mixed particle specimen temperature is much more efficient considering the number of particles that are directly associated with computational time in DEM analysis.

• KIPS Transactions on Software and Data Engineering
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• v.2 no.4
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• pp.267-272
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• 2013

As an important operation with many applications such as data cleaning and duplicate detection, the similarity join is a challenging issue, which finds all pairs of records whose similarities are above a given threshold in a dataset. We propose a new algorithm that uses the prefix filtering principle as strong constraints on generation of candidate pairs for fast similarity joins. The candidate pair is generated only when the current prefix token of a probing record shares one prefix token of an indexing record within the constrained prefix tokens by the principle. This generation method needs not to compute an upper bound of the overlap between two records, which results in reduction of execution time. Experimental results show that our algorithm significantly outperforms the previous prefix filtering-based algorithms on real datasets.

• Bulletin of the Korean Mathematical Society
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• v.41 no.3
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• pp.435-450
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• 2004

We show that two concepts of h-stability and h-stability in variation for nonlinear difference systems are equivalent by using the concept of $n_{\infty}$-summable similarity of their associated variational systems. Also, we study h-stability for perturbed non-linear system y(n+1) =f(n,y(n)) + g(n,y(n), Sy(n)) of nonlinear difference system x(n+1) =f(n,x(n)) using the comparison principle and extended discrete Bihari-type inequality.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.51-60
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• 2016

PURPOSES : The applicability of the mechanics-based similarity concept (suggested by Feng et al.) for determining scaled variables, including length and load, via laboratory-scale tests and discrete element analysis, was evaluated. METHODS: Several studies on the similarity concept were reviewed. The exact scaling approach, a similarity concept described by Feng, was applied in order to determine an analytical solution of a free-falling ball. This solution can be considered one of the simplest conditions for discrete element analysis. RESULTS : The results revealed that 1) the exact scaling approach can be used to determine the scale of variables in laboratory tests and numerical analysis, 2) applying only a scale factor, via the exact scaling approach, is inadequate for the error-free replacement of small particles by large ones during discrete element analysis, 3) the level of continuity of flowable materials such as SCC and cement mortar seems to be an important criterion for evaluating the applicability of the similarity concept, and 4) additional conditions, such as the kinetics of particle, contact model, and geometry, must be taken into consideration to achieve the maximum radius of replacement particles during discrete element analysis. CONCLUSIONS : The concept of similarity is a convenient tool to evaluate the correspondence of scaled laboratory test or numerical analysis to physical condition. However, to achieve excellent correspondence, additional factors, such as the kinetics of particles, contact model, and geometry, must be taken into consideration.

• International Journal of Highway Engineering
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• v.19 no.6
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• pp.23-30
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• 2017

PURPOSES : In this paper, the applicability of DEM to a coarse graining method was evaluated by simulating a series of minicone tests for cement paste. METHODS : First, the fundamental physical quantities that are used in a static liquid bridge model were presented with three basic quantities based on the similarity principle and coarse graining method. Then, the scale factors and surface tensions for six different sizes of particles were determined using the relationship between the physical quantities and the basic quantities. Finally, the determined surface tensions and radii were utilized to simulate the fluidal behavior of cement paste under a minicone test condition, and the final shape of the cement paste with reference DEM particle radii was compared with the final shape of the others. RESULTS : The simulations with adjusted surface tensions for five different radii of particles and surface tension showed acceptable agreement with the simulation with regard to the reference size of the particle, although disagreement increases as the sizes of the particle radii increase. It seems reasonable to increase the particle radii by at least 0.196 cm considering the computational time reduction of 162 min. CONCLUSIONS : The coarse graining method based on the similarity principle is applicable for simulating the behavior of fluidal materials when the behavior of the materials can be described by a static liquid bridge model. However, the maximum particle radius should be suggested by considering not only the scale factor but also the relationship of the particle size and number with the radius of the curve of the boundary geometry.

• Journal of the Korean housing association
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• v.15 no.4
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• pp.9-16
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• 2004

Architectural theories in western architecture have been considered as a basis for answering the fundamental questions of architectonics: proportion, symmetry, color, harmony and so on. Among those the architectural design theory is significant, since it affects the aesthetic evaluation of human perception. This paper gives an outline in applying the traditional design principles of architecture to contemporary architecture by 'unification through similarity' of architectural components such as form, scale, texture and color. As we see from this research, unification can be achieved in a design by the combination of the four components; that is, to balance between the four above-mentioned components in buildings, through the similarity of one or more of these components.

• Journal of the Korea Society of Computer and Information
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• v.24 no.9
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• pp.77-82
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• 2019

Collaborative filtering is a popular technique for recommender systems and used in many practical commercial systems. Its basic principle is select similar neighbors of a current user and from their past preference information on items the system makes recommendations for the current user. One of the major problems inherent in this type of system is data sparsity of ratings. This is mainly caused from the underlying similarity measures which produce neighbors based on the ratings records. This paper handles this problem and suggests a new similarity measure. The proposed method takes users rating patterns into account for computing similarity, without just relying on the commonly rated items as in previous measures. Performance experiments of various existing measures are conducted and their performance is compared in terms of major performance metrics. As a result, the proposed measure reveals better or comparable achievements in all the metrics considered.

• Journal of Educational Research in Mathematics
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• v.20 no.1
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• pp.57-71
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• 2010

Similarity between concept and concept, principle and principle, theory and theory is known as a strong motivation to mathematical knowledge construction. Metaphor and analogy are reasoning skills based on similarity. These two reasoning skills have been introduced as useful not only for mathematicians but also for students to make meaningful conjectures, by which mathematical knowledge is constructed. However, there has been lack of researches connecting the two reasoning skills. In particular, no research focused on the interplay between the two in didactic transposition. This study investigated the process of knowledge construction by metaphor and analogy and their roles in didactic transposition. In conclusion, three kinds of models using metaphor and analogy in didactic transposition were elaborated.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2069-2087
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• 2023

In nuclear power plant (NPP) accidents, the containment is subject to high temperatures and high internal pressures, which may further trigger serious chain accidents such as core meltdown and hydrogen explosion, resulting in a significantly higher accident level. Therefore, studying the mechanical performance of a containment under high temperature and high internal pressure is relevant to the safety of NPPs. Based on similarity principles, the 1:3.2 scale model of a prestressed concrete containment vessel (PCCV) of a NPP was designed. The loading method, which considers the thermal-pressure coupling conditions, was used. The mechanical response of the PCCV was investigated with a simultaneous increase in internal pressure and temperature, and the failure mechanism of the PCCV under thermal-pressure coupling conditions was revealed.