• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6C
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• pp.369-376
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• 2006

Similarity rule in order to predict the field settlement and consolidation time from oedometer test is not clear because of the thickness, loading time, rate of loading increase, dependence on strain inherent of clay. To investigate the one-dimensional consolidation tests with permeability tests varied loading period and specimen thickness were carried out the application of similarity rule. Main conclusions are 1) f(=1+e)-logk line is a unique property of the soil, 2) $c_{\nu}$, k need no correction, 3)similarity rule is depends on the positions of f-logp line and primary consolidation line.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.7
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• pp.138-146
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• 2003

A critical issue in area-based stereo matching lies in selecting a fixed rectangular window size. Previous stereo methods doesn't deal effectively with occluding boundary due to inevitable window-based problems, and so give inaccurate and noisy matching results in areas with steep disparity variations. In this paper, a variable window approach is presented to estimate accurate, detailed and smooth disparities for three-dimensional structure reconstruction. It makes the smoothing of depth discontinuity reduced by evaluating corresponding correlation values and intensity gradient-based similarity in the three-dimensional disparity space. In addition, it investigates maximum connected match candidate points and then devise the novel arbitrarily shaped variable window representative of a same disparity to treat with disparity variations of various structure shapes. We demonstrate the performance of the proposed variable window method with synthetic images, and show how our results improve on those of closely related techniques for accuracy, robustness, matching density and computing speed.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.185-193
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• 2003

Basic flow fields of two dimensional V flames were examined as a preliminary work to study the instability of premixed flame with vorticity generation. Laminar premixed propane and methane flame were anchored by electrically heated wire to make two dimensional V flames. Flow fields were measured mainly by PIV(Particle Image Velocimetray) and the results were compared with those obtained by LDV(Laser Doppler Velocimetry) to confirm their reliability. Because the curvatures of V flames are so small, V flames were locally assumed to be inclined planar flames in gravitational field. The measured flow fields were locally compared with those of analytical solutions, which showed the qualitatively similar results. In downstream region, the vorticity fields were nearly constant except region near the center line, which support the assumption of locally one dimensional flame. Besides it was tried to find experimentally the similarity of flow fields in downstream region. Finally, stability diagram of propane and methane flames were drawn for the equivalence ratio less than one and the wide range of mean velocity.

• 한국전산유체공학회:학술대회논문집
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• 2009.04a
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• pp.298-302
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• 2009

Numerical analysis of two dimensional incompressible laminar free jet flow was carried out by using finite difference SMAC scheme. Flow characteristics of free jet flow such as jet width, similarity of jet velocity and hypothetical origin were investigated for different Reynolds numbers of Re=30 and 100. The reliability of predictions were confirmed by comparison with exact solution. Non-dimensional velocity distribution showed similarity of jet flow velocity after initial region. In the region of laminar flow, the location of hypothetical origin becomes more distant with Reynolds number.

• Journal of applied mathematics & informatics
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• v.9 no.2
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• pp.793-806
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• 2002

Feature-based similarity retrieval become an important research issue in image database systems. The features of image data are useful to discrimination of images. In this paper, we propose the highspeed k-Nearest Neighbor search algorithm based on Self-Organizing Maps. Self-Organizing Maps (SOM) provides a mapping from high dimensional feature vectors onto a two-dimensional space. The mapping preserves the topology of the feature vectors. The map is called topological feature map. A topological feature map preserves the mutual relations (similarity) in feature spaces of input data. and clusters mutually similar feature vectors in a neighboring nodes. Each node of the topological feature map holds a node vector and similar images that is closest to each node vector. In topological feature map, there are empty nodes in which no image is classified. We experiment on the performance of our algorithm using color feature vectors extracted from images. Promising results have been obtained in experiments.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.35 no.1
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• pp.101-106
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• 2012

Ship handling simulator is a virtual ship navigating system with three dimensional screen system and simulation programs. FTS simulation can produce theoretically infinite experiment tests without time constraint, but which results in collecting determinstic observations. RTS simulation can collect statistical observations but has disadvantage of spending at least 30 minutes for a single experiment. The previous studies suggested that the number of experiment conditions to be tested could be reduced to obtain random data with RTS simulation by focusing on highly difficult experiment condition for ship handling. It has the limitation of not estimating the distribution of ship handling difficulty for the route. In this paper, similarity and clustering analysis are suggested for reduction methodology of experiment conditions. Similarity of experiment conditions are measured as follows: euclidean distance of ship handling difficulty index and correlation matrix of distance differences from the designed route. Clustering analysis and multi-dimensional scaling are applied to classify experiment conditions with measured similarity into reducing the number of RTS simulation conditions. An empirical result on Dangin harbor is shown and discussed.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.9 no.2
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• pp.99-104
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• 2009

The turn-to-turn short is one major fault of the motor faults of BLDC motors and can appear frequently. When the fault happens, the motor can be operated without breakdown, but it is necessary to maintain the motor for continuous working. In past research, several methods have been applied to detect winding faults. The representative approaches have been focusing on current signals, which can give important information to extract features and to detect faults. In this study, current sensors were installed to measure signals for fault detection of BLDC motors. In this study, the Park's vector method was used to extract the features and to isolate the faults from the current measured by sensors. Because this method can consider the three-phase current values, it is useful to detect features from one-phase and three-phase faults. After extracting two-dimensional features, the final feature was generated by using the two-dimensional values using the distance equation. The values were used in fuzzy similarity to isolate the faults. Fuzzy similarity is an available tool to diagnose the fault without model generation and the fault was converted to the percentage value that can be considered as possibility of the fault.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.284-287
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• 2003

Previous stereo methods doesn't deal effectively with depth discontinuity due to inevitable window-based problems, and so give inaccurate and noisy matching results in areas with steep disparity variations. In this paper. a variable window approach is presented to estimate accurate, detailed and smooth disparities with three-dimensional disparity space. It makes the smoothing of depth discontinuity reduced by evaluating corresponding correlation values and intensity gradient-based similarity in the space. In addition, it devises the novel arbitrarily-shaped variable window to treat with disparity variations of various structure shapes. We show how our results improve on those of closely related techniques for accuracy, robustness. matching density and computing speed.

• Journal of computational fluids engineering
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• v.12 no.4
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• pp.20-27
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• 2007

Two-dimensional stagnation flow toward a plane wall coated with magnetic fluid of uniform thickness is investigated. The flow field is represented as a similarity solution of the Navier-Stokes equation for this incompressible laminar flow. The resulting third order ordinary differential equation is solved numerically by using the shooting method and by determining two shooting parameters so as to satisfy the boundary and interface conditions. Features of the flow including streamline patterns are investigated for the varying values of density ratio, viscosity ratio, and Reynolds number. An adverse flow with double eddy pair in magnetic fluid region is found to emerge as the Reynolds number becomes higher than a threshold value. The results for the interface velocity, interface and wall shear stress, and boundary layer and displacement thickness are also presented.

• The KIPS Transactions:PartD
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• v.8D no.4
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• pp.305-312
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• 2001

Recently, high-dimensional index structures have been required for similarity search in such database applications s multimedia database and data warehousing. In this paper, we propose a new cell-based signature tree, called CS-tree, which supports efficient storage and retrieval on high-dimensional feature vectors. The proposed CS-tree partitions a high-dimensional feature space into a group of cells and represents a feature vector as its corresponding cell signature. By using cell signatures rather than real feature vectors, it is possible to reduce the height of our CS-tree, leading to efficient retrieval performance. In addition, we present a similarity search algorithm for efficiently pruning the search space based on cells. Finally, we compare the performance of our CS-tree with that of the X-tree being considered as an efficient high-dimensional index structure, in terms of insertion time, retrieval time for a k-nearest neighbor query, and storage overhead. It is shown from experimental results that our CS-tree is better on retrieval performance than the X-tree.