• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.2
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• pp.91-102
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• 2010

This study analyzed methodologies for determining the representative direction of a storm event. The mean direction, median direction, and modal direction of von Mises distribution were considered as representative directions. In addition, the results with and without considering the storm moving distance were also compared. As results, the modal directions of von Mises distribution were found to explain the directional characteristics of a moving storm much better than other methods. Also, it was found that the storm moving distance has a significant effect on the determination of representative directions of a moving storm, whose uncertainty can also be decreased significantly by considering the moving distance.

• Journal of the Korean Society of Hazard Mitigation
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• v.10 no.6
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• pp.109-117
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• 2010

This study quantified the storm direction for a river basin by applying the von Mises distribution, also determined the representative storm direction. Additionally, the whole procedure was repeated for several storm types such as frontal, typhoon and convective storms for their comparison. From the results derived by analyzing a total of 101 storm events for the Naesung river basin, the von Mises distribution was found to explain the directional characteristics of storms. The representative moving directions derived for three different storm types were significantly different each other, which is coincident with the climate of Korea. The results derived in this study could be helpful to estimate more quantitatively the difference in the runoff response with respect to the moving direction of a storm.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.3B
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• pp.233-242
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• 2011

This study quantified directional properties of channel network and hill slope for a river basin by applying the von Mises distribution, also examined the relation between them. Ultimately, it was examined that whether the directional properties of channel network and hill slope have a certain relation, which might be considered to the rainfall-runoff modeling. From the results derived by analyzing the Naesung stream basin, the von Mises distribution was found well to explain the directional characteristics of directional properties of channel network. There was a clear relation between directional properties of channel network and hill slope. The higher-order streams also showed very obvious modal characteristics. The results derived in this study could be helpful to estimate more quantitatively the difference in the runoff response with respect to the directional properties of channel network and hill slope.

• Communications for Statistical Applications and Methods
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• v.14 no.3
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• pp.517-530
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• 2007

We studied a modelling process for unimodal and multimodal circular data by using von Mises and its mixture distribution. In particular we suggested EM algorithm to find ML estimates of the mixture model. Simulation results showed the suggested methods are very accurate. Applications to two kinds of real data sets are also included.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.13 no.1
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• pp.59-66
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• 2013

In this paper, we propose a probabilistic framework for model-based clustering of direction of arrival (DOA) data to obtain stable sound source localization (SSL) estimates. Model-based clustering has been shown capable of handling highly overlapped and noisy datasets, such as those involved in DOA detection. Although the Gaussian mixture model is commonly used for model-based clustering, we propose use of the von Mises mixture model as more befitting circular DOA data than a Gaussian distribution. The EM framework for the von Mises mixture model in a unit hyper sphere is degenerated for the 2D case and used as such in the proposed method. We also use a histogram of the dataset to initialize the number of clusters and the initial values of parameters, thereby saving calculation time and improving the efficiency. Experiments using simulated and real-world datasets demonstrate the performance of the proposed method.

• Journal of Biomedical Engineering Research
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• v.19 no.1
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• pp.53-58
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• 1998

This study examined the distribution of bone mineral density(BMD) and the von Mises stress in the patella. The BMD of eighteen patellae were determined by using quantitative computed tomography and imaging analysis software. It was found that the BMD of the patella varied with location. BMD values were largest at the superior and lateral regions and decreased inferiorly and medially. This distribution appeared to correspond to the organization of trabeculae within the patella. A two-dimensional finite element analysis was performed on each patella. It was also found that the maximum von Mises stress in the patella occurred along the cortical shell on the non-articular surface. The trabecular von Mises stress existed in the posterior region of the patella. These findings demonstrated the potential for finite element studies in vivo. Further, such studies may lead to the development of custom-made, patient-specific patella prostheses.

• The Journal of Advanced Prosthodontics
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• v.5 no.4
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• pp.434-439
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• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Journal of Technologic Dentistry
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• v.42 no.4
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• pp.348-354
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• 2020

Purpose: Zirconia is differentiated from other ceramics because of its high resistance to corrosion and wear, excellent flexural strength (900~1400 MPa), and high hardness. Dental zirconia with proven mechanical/biological stability is suitable for the manufacture of implants. However, there are limited in vivo studies evaluating stress distribution in zirconia compared with that in titanium implants and studies analyzing finite elements. This study was conducted to evaluate the stress distribution of the supporting bone surrounding zirconia and titanium implants using the finite element analysis method. Methods: For finite element analysis, a single implant-supported restoration was designed. Using a universal analysis program, eight occlusal points were set in the direction of the occlusal long axis. The occlusal load was simulated at 700 N. Results: The zirconia implant (47.7 MPa) von Mises stress decreased by 5.3% in the upper cortical bone compared with the titanium implant (50.2 MPa) von Mises stress. Similarly, the zirconia implant (20.8 MPa) von Mises stress decreased by almost 4% in the cancellous bone compared with the titanium implant (21.7 MPa) von Mises stress. The principal stress in the cortical and cancellous bone exhibited a similar propensity to von Mises stress. Conclusion: In the supporting bone, the zirconia implant is able to reduce bone resorption caused by mechanically transferred stress. It is believed that the zirconia implant can be a potential substitute for the titanium implant by reinforcing aesthetic characteristics and improving stress distribution.

• The Korean Journal of Applied Statistics
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• v.22 no.2
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• pp.237-248
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• 2009

The probability of default on the credit evaluation study is represented as a linear combination of two distributions of default and non-default, and the distribution of the probability of default are generally known in most cases. Except the well-known Kolmogorov-Smirnov statistic for testing the identity of two distribution, Kuiper, Cramer-Von Mises, Anderson-Darling, and Watson test statistics are introduced in this work. Under the assumption that the population distribution is known, modified Cramer-Von Mises, Anderson-Darling, and Watson statistics are proposed. Based on score data generated from various probability density functions of the probability of default, the modified test statistics are discussed and compared.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.6
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• pp.727-735
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• 2005

Statement of problem. Platform switching in implant prosthesis has been used for esthetic and biological purpose. But there are few reports for this concept. Purpose. The purpose of this study is evaluation of platform switching in wide implant by three dimensional finite element analysis. Materials and Methods. The single implant and prosthesis was modeled in accordance with the geometric designs for Osstem implant system. Three-dimensional finite element models were developed for (1) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with wide cemented abutment, titanium alloy abutment screw, and prosthesis (2) a wide diameter 3i type titanium implant 5 mm in diameter, 13 mm in length with regular cemented abutment, titanium alloy abutment screw and prosthesis(platform switching) was made for finite element analysis. The abutment screws were subjected to a tightening torque of 30 Ncm. The amount of preload was hypothesized to 650N, and round and flat type prostheses were loaded to 200 N. Four loading offset point (0, 2, 4, 6 mm from the center of the implants) were evaluated. Models were processed by the software programs HyperMesh and ANSA. The PAM-CRASH 2G simulation software was used for analysis of stress. The PAM-VIEW and HyperView were used for post processing. Results. The results from experiment were as follows; 1. von Mises stress value is increased in order of bone, abutment, implant and abutment screw. 2. von Mises stress of abutment screw is lower when platform switching. 3. von Mises stress of implant is lower when platform switching until loading offset 4 mm. 4. von Mises stress of abutment is similar between each other. 5. von Mises stress of bone is slightly higher when platform switching. Conclusion. The von Mises stress pattern of implant components is favor when platform switch ing but slightly higher in bone stress distribution than use of wide abutment. The research about stress distribution is essential for investigation of the cortical bone loss.