• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 한국공작기계학회 2000년도 춘계학술대회논문집 - 한국공작기계학회
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• pp.391-396
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• 2000

Today most companies are designing their automobile shapes by using 3 dimensional CAD software, CATIA. And they used to design 2 dimensional press dies to do some elastic work on their products, but they are currently trying to make use of dimensional software, Pro-Engineer. In this case, they have to change the 3 dimensional product design data to the proper format data for the following process. This paper will show the data loss and the deformation during data transfer between CATIA and Pro-Engineer, and then suggest a solution for these problems. Product's surface will be automatically placed by automatic press tipping angle setting in CATIA to prevent the product from being stuck in the press die. The 2 dimensional section view which is based on the tipping angle setting is created by Z-map. And, to remove the data loss and the data deformation in pro-Engineer, the product surface are delivered to the next process after it is changed to the 2 dimensional Z-map curves in CATIA. finally, this paper suggests an algorithm to develop the automatic design program for the press layout which regenerates product shape surface from the previous process.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송공학회 2009년도 IWAIT
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• pp.551-556
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• 2009

3-D CAD (Computer Aided Design) system is an indispensable tool for manufacturing. A lot of engineers have studied for the methods to generate a curved surface on an N-sided shape, which is the basic technology of 3-D CAD systems. This surface generation, however, has three problems on the case of long and narrow shapes: the resultant surface is distorted, the surface is not continuous to adjacent surfaces, or additional user inputs are required to generate the surface. Conventional methods have not yet solved these problems at the same time. In this paper, we propose the method to generate internal curves that divide a long and narrow shape into regular N-sided sections so as to divide the shape into an N-sided section and four-sided ones. Our method controls the shape of internal curves by dividing an N-sided long and narrow shape into an N-sided section and four-sided ones, and solves distortion of the generated curved surface. In addition, each of the generated sections is interpolated with G1-continuous surfaces. This process does not require any user's further input. Therefore, the three problems mentioned above will be solved at the same time.

• Proceedings of the KSME Conference
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• 대한기계학회 2003년도 추계학술대회
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• pp.1157-1162
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• 2003

Behavior of aluminum alloy embedding a particle was investigated at room temperature under ECAP. Finite element analysis by using ABAQUS shows that ECAP is a useful tool for eliminating residual porosity in the specimen, and much more effective under friction condition. The simulation, however, shows considerably low density distributions for matrix near a particle at which rich defects may occur during severe deformation. Finite element results of effective strains and deformed shapes for matrix with a particle were compared with theoretical calculations under simple shear stress. Also, based on the distribution of the maximum principal stress in the specimen, Weibull fracture probability was obtained for particle sizes and particle-coating layer materials. The probability was useful to predict the trend of more susceptible failure of a brittle coating layer than a particle without an interphase in metal matrix composites.

• Proceedings of the KOSOMBE Conference
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• 대한의용생체공학회 1997년도 추계학술대회
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• pp.280-283
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• 1997

Human cervical spine has to protect the neural components and vascular structures. Also, it must have the flexibility afforded by an extensive range of motion to integrate the head with the body and environment. Because of these two-sided features, human cervical spine has very complicated shapes and their injury mechanisms are not fully understood yet. We have developed analytical model of human CS by using the finite element method. The model has been verified with in vivo and in vitro experimental results. From the qualitative analysis of simulation results, we were able to explain some of the fundamental mechanisms of neck pain. Further more, this FE model of human CS can be used as an analytical tool or biomechanical design of the clinical device and safety restraints.

• International Journal of Precision Engineering and Manufacturing
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• 제9권2호
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• pp.75-80
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• 2008

The fabrication of complex three-dimensional electrodes for micro electrical discharge machining (micro-EDM) is an important issue in the field of micromachining Localized electrochemical deposition (LECD) is a simple and inexpensive technique for fabricating micro-EDM electrodes. This study presents a new process for manufacturing electrodes with complex cross-sections using masks of different shapes, In this process, a non-conductive mask is placed between an anode and cathode that are immersed in a plating solution of acidified copper sulfate. The LECD is achieved by applying a pulsed voltage between the anode and cathode, which are separated by a small distance. In this setup, the cathode is placed above the anode and the mask, so that the deposited electrode can be used directly for EDM without changing the tool orientation. We found that the microstructure of the deposited electrode is influenced by the concentration of the plating solution and organic additives. Moreover, the values of the voltage, frequency, and duty cycle of the pulsed input have significant effects on the microstructure of the fabricated electrode. Finally, the optimum values of the voltage, frequency, and duty cycle were determined for the most effective fabrication of complex-shaped electrodes.

• Communications for Statistical Applications and Methods
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• 제25권4호
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• pp.373-383
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• 2018

The spatial scan statistic is a widely used method to detect spatial clusters. The method imposes a large number of scanning windows with pre-defined shapes and varying sizes on the entire study region. The likelihood ratio test statistic comparing inside versus outside each window is then calculated and the window with the maximum value of test statistic becomes the most likely cluster. The results of cluster detection respond sensitively to the shape and the maximum size of scanning windows. The shape of scanning window has been extensively studied; however, there has been relatively little attention on the maximum scanning window size (MSWS) or maximum reported cluster size (MRCS). The Gini coefficient has recently been proposed by Han et al. (International Journal of Health Geographics, 15, 27, 2016) as a powerful tool to determine the optimal value of MRCS for the Poisson-based spatial scan statistic. In this paper, we apply the Gini coefficient to normal-based spatial scan statistics. Through a simulation study, we evaluate the performance of the proposed method. We illustrate the method using a real data example of female colorectal cancer incidence rates in South Korea for the year 2009.

• Tribology and Lubricants
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• 제21권4호
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• pp.185-192
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• 2005

The press cutter is productive equipment that practically manufactures mechanical components and polymer-based materials such as fabrics, papers, films, leathers, and rubbers into the desired shapes using a press cutting tool. The plate cutting process is one of the primary energy absorbing mechanisms in a grounding or collision event between a press cutter and a material on a die. The cutting mechanism is complicated and involves plastic flows of a plate in the vicinity of the tip, friction between the wedge and the plate, deformation of the plate. In this paper, we studied the effect of friction between cutter and plastic sheet far producing precise and superior products. In this paper, the press cutter is analyzed numerically using MARC finite element program for a optimization design of a press cutter. The FEM computed results show that the maximum von Mises stress is concentrated on the tip of a press cutter, which may lead to the edge wear or impact wear of the sharp cutter. Based on the FEM result and Taguchi's experimental design method, the optimized design model 9 for a press cutter is recommended as a best one.

• Journal of Theoretical and Applied Mechanics
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• 제2권1호
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• pp.31-50
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• 1996

In this paper, a finite element analysis based on the local approach concept to fracture in the continuum damage mechanics is performed to analyze ductile fracture in two dimensional quasi-static state. First an isotropic damage model based on the generalized concept of effective stress is proposed for structural materials in the context of large deformation. In this model, the stiffness degradation is taken as a measure of damage and so, the fracture phenomenon can be explained as the critical deterioration of stiffness at a material point. The modified Riks' continuation technique is used to solve incremental iterative equations. Crack propagation is achieved by removing critically damaged elements. The mesh size sensitivity analysis and the simulation of the well known shearing mode failure in plane strain state are carried out to verify the present formulation. As numerical examples, an edge cracked plate and the specimen with a circular hole under plane stress are taken. Load-displacement curves and successively fractured shapes are shown. From the results, it can be concluded that the proposed model based on the local approach concept in the continuum damage mechanics may be stated as a reasonable tool to explain ductile fracture initiation and crack propagation.

• Health Policy and Management
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• 제11권1호
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• pp.37-61
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• 2001

In the course of this research, we developed FRIS(Food Replica Information System), which calculates calories and nutrient values of foods in a very simple and interesting manner, and experienced of application to some communities. We expect that individuals will have opportunities to raise their consciousness of food, nutrients, and healthy living by participating in FRIS. 154 kinds of commonly consumed Korean foods were selected and one serving sized food replicas, having the same shapes, size, and color as the real foods, were constructed with attached bar code labels. An application program with food replicas and bar code was also developed in order to provide information on calories and nutrient values for people's meals or selected foods based on survey results of housewives' requirements related to foods and nutrients. FRIS should be a basic tool in nutrition education and consultation. Its applicability would vary according to the nutritionist's flexibility and contents of developed application programs. Technical stability should be strengthened and more useful contents of application prograln be added to spread the use of the system. Additionally, in future research, more delicate models should be developed and an analytical method should be applied to examine the effects of FRIS to individual behavioral changes in their eating habits.

• Journal of the Korean Society of Industry Convergence
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• 제16권3호
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• pp.85-93
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• 2013

The MCT has been most extensively used in the machining. In particular, the ball endmill has been mainly adopted for finishing on the free- form surface. The advancement of CAD/CAM software has made it possible to develop various cutting pattern methods and to create diverse tool routes. Therefore, the current research made an attempt to find the optimal cutting pattern among the seven cutting patterns (i.e., Follow Periphery, Zig, Zig Zag, Concentric Zig, Concentric Zig Zag, Radial Zig, Radial Zig Zag) when aluminium 6000 series were machined by the ball endmill. The optimal pattern was found by comparing different shapes and surface roughness produced by the seven patterns. The current research found that each cutting pattern produced its own unique geometric features on the machined surface. It was found that the Radial Zig cutting pattern produced the lowest roughness on the flat surfaces. The Radial Zig Zag cutting pattern was found to produce the most accurate free-form surface. Finally, the most efficient cutting pattern in terms of machining time turned out to be the Follow Periphery.