• Journal of Korea Multimedia Society
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• 제7권3호
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• pp.427-437
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• 2004

Shape comparison between 3D models is essential for shape recognition, retrieval, classification, etc. In this paper, we propose a method for comparing 3D shapes, which is invariant under translation, rotation and scaling of models and is robust to non-uniformly distributed and incomplete data sets. first, a modal model is constructed from input data using vibration modes and then shape similarity is evaluated with modal strain energy. The proposed method provides global-to-local ordering of shape deformation using vibration modes ordered by frequency Thus, we evaluated similarity in terms of global properties of shape without being affected localised shape features using ordered shape representation and modal strain one energy.

• The KIPS Transactions:PartA
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• 제10A권4호
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• pp.357-368
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• 2003

Evaluation of shape similarity for 3D models is essential in many areas - medicine, mechanical engineering, molecular biology, etc. Moreover, as 3D models are commonly used on the Web, many researches have been made on the classification and retrieval of 3D models. In this paper, we describe methods for 3D shape representation and major concepts of similarity evaluation, and analyze the key features of recent researches for shape comparison after classifying them into four categories including multi-resolution, topology, 2D image, and statistics based methods. In addition, we evaluated the performance of the reviewed methods by the selected criteria such as uniqueness, robustness, invariance, multi-resolution, efficiency, and comparison scope. Multi-resolution based methods have resulted in decreased computation time for comparison and increased preprocessing time. The methods using geometric and topological information were able to compare more various types of models and were robust to partial shape comparison. 2D image based methods incurred overheads in time and space complexity. Statistics based methods allowed for shape comparison without pose-normalization and showed robustness against affine transformations and noise.

• Korean Journal of Computational Design and Engineering
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• 제9권4호
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• pp.306-314
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• 2004

This paper explains the qualitative shape representation scheme and general shape analysis procedure based on shape feature categories. It takes two different groups of architectural drawings as examples and comparer them so as to confirm that the procedure is capable of comparing one group with another. In order to verify the validity of qualitative shape representation scheme, we used statistical methods as well as symbolic representation and analysis techniques. This paper concludes that two different groups of architectural drawings of similar kind are analyzed to be distinguished and specifically characterized. 11 drawings of Kahn and 13 drawings of Aalto are taken into considerations. Linear regressions are used in characterizing the shape featural relationships.

• Ocean Systems Engineering
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• 제11권1호
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• pp.83-97
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• 2021

The submerged U-shape breakwater interaction with the solitary wave is simulated by the Boussinesq equations using the finite-difference scheme. The wave reflection, transmission, and dissipation (RTD) coefficients are used to investigate the U-shape breakwater's performance for different crest width, Lc1, and indent breakwater height, du. The results show that the submerged breakwater performance for a set of U-shape breakwater with the same cross-section area is related to the length of submerged breakwater crest, Lc1, and the distance between the crests, Lc2 (or the height of du). The breakwater has the maximum performance when the crest length is larger, and at the same time, the distance between them increases. Changing the Lc1 and du of the U-shape breakwaters result in a significant change in the RTD coefficients. Comparison of the U-shape breakwater, having the best performance, with the averaged RTD values shows that the transmission coefficients, Kt, has a better performance of up to 4% in comparison to other breakwaters. Also, the reflection coefficients KR and the diffusion coefficients, Kd shows a better performance of about 30% and 55% on average, respectively. However, the model governing equations are non-dissipative. The non-energy conserving of the transmission and reflection coefficients due to wave and breakwater interaction results in dissipation type contribution. The U-shape breakwater with the best performance is compared with the rectangular breakwater with the same cross-section area to investigate the economic advantages of the U-shape breakwater. The transmission coefficients, Kt, of the U-shape breakwater shows a better performance of 5% higher than the rectangular one. The reflection coefficient, KR, is 60% lower for U-shape in comparison to rectangular one; however, the diffusion coefficients, Kd, of U-shape breakwater is 35% higher than the rectangular breakwater. Therefore, we could say that the U-shape breakwater has a better performance than the rectangular one.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 한국공작기계학회 2004년도 춘계학술대회 논문집
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• pp.287-292
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• 2004

In this study, we made a comparative study of backpropagation neural network and probabilistic neural network and bayesian classifier and perceptron as shape recognition algorithm of welding flaws. For this purpose, variables are applied the same to four algorithms. Here, feature variable is composed of time domain signal itself and frequency domain signal itself, Through this process, we confirmed advantages/disadvantages of four algorithms and identified application methods of few algorithms.

• The Research Journal of the Costume Culture
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• 제15권2호
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• pp.252-264
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• 2007

The purpose of this study was to compare two analytical methods classifying foot shape. The methods compared were cluster analysis method and foot index analysis method. This study defined the women's foot shape by these methods. 39 foot measurements which were automatically collected using the three dimensional foot scanner were analyzed. 203 Korean women in age 20s were participated in the anthropometric survey. Their foot shapes were classified into 5 foot types by cluster analysis: short & slim shape, flat shape, short & slender shape with slightly distorted toe, long and big shape, and short & wide shape. The foot measurements were also analyzed by the ratio of foot width and length. Five foot types that were classified by cluster analysis and three foot types that were classified by the foot index were compared. The comparison shows that cluster analysis precisely defined foot shapes. It was suggested that made-to-measure shoes making industry may adopt the foot shape analysis method utilizing cluster analysis.

• International Journal of Aeronautical and Space Sciences
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• 제15권1호
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• pp.20-31
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• 2014

This paper deals with the development of a realistic shape optimization of damaged columns that are subjected to conservative and non-conservative forces, using the Genetic Algorithm (GA). The analysis is based on the design of the most optimized shape of the column under the constraint of constant weight, considering the Static, Vibrational, and Flutter characteristics. Under the action of conservative and non-conservative longitudinal forces, an elastic column loses its stability. A numerical analysis based on FEM has been performed on a uniform damaged column, to compute the fundamental buckling load, vibration frequency, and flutter load, under various end restraints. An optimization search based on the Genetic Algorithm is then executed, to find the optimal shape design of the column. The optimized column references the one having the highest buckling load, highest vibration frequency, and highest flutter load, among all the possible shapes of the column, for a given volume. A comparison is then made between the values obtained for the optimized damaged column, and those obtained for the optimized undamaged column. The comparison reveals that the incorporation of damage in the column alters its optimal shape to only a certain extent. Also, the critical load and frequency values for the optimized damaged column are comparatively low, compared with those obtained for the optimized undamaged column. However, these results hold true only for moderate-intensity damage cases. For high intensity damage, the optimal shape may not remain the same, and may vary, according to the severity of damage.

• Journal of Korean Medical classics
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• 제33권1호
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• pp.61-80
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• 2020

Objectives : To clarify the construction, changes, and contents of the diagrams of spleen through comparison of 30 different diagrams originated from Mingtangzangfutu. Methods : The diagrams were analyzed in whole shape, ratio between width and height, shape of the lower part, and concavo-convex of the middle part, then matched to the characteristics of the section diagram. The contents of the diagram of the spleen were newly interpreted with comparison to the classical texts. Results : The whole shape is described to be a long sword, long stick, bottle gourd, western pear, sole of feet. The height to width ratio was mostly above 4.0:1, but those listed in the 『Bianquemaishunaning』 and 『Hehensancaituhui』 were 1.9:1~1.0:1, most similar to the numbers described in the 『Nanjing』. The shape of the lower part was narrow and sharp, narrow and flat or wide and flat. To analyze through affiliation characteristic, properties of other affiliations could be found. In comparison to classical texts, the diagrams could be found to be affected by 『Nanjing』 and Wangbing's annotations. The diagrams of the spleen should be composed of the spleen, the cord of spleen, and Sangao(散膏); but those which distinguish the spleen and the cord of spleen are twelve. The description of its shape as being similar to sword or sickle seems to come from Lichan's misunderstanding of the diagram in 『Zhenjiujuying』. Those that mention Sangao are merely two and their opinion on the position are different from each other; both did not identify it with the pancreas. Conclusions : In the process of the diagrams differentiating into 30 they were affected by the classical texts. The various changes seem to come from difference in understanding of the content composition of the diagram of the spleen.

• Journal of the Society of Naval Architects of Korea
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• 제39권2호
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• pp.28-33
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• 2002

The characteristics of hull-pieces are large quantity, comparatively large piece-size, and different each shape. For the more, in the forming process(including Line-Heating Process) of curved hull pieces, shape checking processes including initial shape measurement and forming shape measurement of the each pieces are needed to achieve a given accuracy. So, the forming process of large curved hull pieces needs efficient measurement and comparison technique to check the shape and ensure the forming-accuracy In this paper, we try to construct integrated S/W, H/W system for efficient measurement and comparison of large curved hull pieces, which can apply to above forming environment.

• Journal of Technologic Dentistry
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• 제39권2호
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• pp.93-99
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• 2017

Purpose: With the development of digital dental technology, we are manufacturing prosthetic crown in various ways. However, the wax-up method that makes existing prosthetic crown is also used steadily. Thus, we will compare the shape of the crown designed with wax-up and the crown designed with CAD. Methods: Sculpt the crown with wax-up on the model to 10 dental technicians. The same model was used to design the crown CAD. Measure the size of the sculpted crown. The shapes were compared in three dimensions. Results: As a result, we could observe a difference in size and shape in crown designed with wax - up crown and crown. Conclusion: These results suggest that there are differences according to the method of carving crown and the method of processing.