• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.200-205
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• 1993

The automatic forming sequence design system can determine desirable operation sequences even if they have little experience in the design of cold forging process. This system is proposed,which generates forming sequence plans for the multistage cold forging of zxisymmetrical solid products. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the product is a key in planning processes. Forming sequence for the part can be determined by means of primitive geometries such as cylinder,cone, convex, and concave. By utilizing this geometrical characteristics(diameter,height, and radius),the product geometry is expressed by a list of the pnmitive geometries. Accordingly, the forming sequence design is formulated as the search problem which starts with a billet geometry and finishes with a given product one. Using the developed system, the sequence drawing with all dimensions, which includes the proper sequence of operations for the part, is generated under the environment of AutoCAD. The preliminary choice of some feasible forming sequences can verify by using the finite element simulation.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.150.4-150
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• 2001

The geometry PIG provides pipeline operators with continuous measurement of pipe centerline coordinates, bend radius, displacement, and bending strain in a single pass through the pipeline. This study introduces the developed geometry PIG(Pipeline Inspection Gauge) which is used for geometry surveys. This tool is equipped with the several sensor systems. The Inertial Navigation System (INS) comprises angle rate gyros and linear accelerometers. The system measures the precise path of the PIG during its traverse of the pipeline. This system is also used to produce a detailed map of the lire, measure curvature. Odometers measure the PIG´s distance moved along the line and instantaneous speed during the PIG run. Caliper sensors measure pipeline ...

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.4 no.2
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• pp.193-198
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• 2004

This paper describes an automatic finite element (FE) mesh generation for three-dimensional structures consisting of tree-form surfaces. This mesh generation process consists of three subprocesses: (a) definition of geometric model, (b) generation of nodes, and (c) generation of elements. One of commercial solid modelers is employed for three-dimensional solid structures. Node is generated if its distance from existing node points is similar to the node spacing function at the point. The node spacing function is well controlled by the fuzzy knowledge processing. The Voronoi diagram method is introduced as a basic tool for element generation. Automatic generation of FE meshes for three-dimensional solid structures holds great benefits for analyses. Practical performances of the present system are demonstrated through several mesh generations for three-dimensional complex geometry.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.228-234
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• 2001

NTMS(Non-contact Tilted-angle Measuring System) is developed by using the principle that the magnetic field of an anisotropic magnet's inner space is uniform and it's possible to measure the strength of the magnetic field using a linear hall effect sensor. In order to implement the caliper system of the geometry PIG(Pipeline Inspection Gauge) which has high accuracy and proper output voltage of the hall sensor without additional driving module or a signal amplifier, it is necessary to consider the size of the magnet, the inner space and back-yoke and the position of pin-hole in the magnet. So the optimal design method of the caliper system is proposed through analysis of NTMS's magnetic field adopting a FEM(Finite Element Method). The experimental results show that the developed caliper system can be used for the geometry pig with good performances.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.917-920
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• 2005

This paper presents 3D graphics geometry processor for mobile applications. Geometry stage needs to cope with the large amount of computation. Geometry stage consists of transformation process and lighting process. To deal with computation in geometry stage, the vector processor that is based on pipeline chaining is proposed. The performance of proposed 3D graphics geometry processor is up to 4.3M vertex/sec at 100 MHz. Also, the designed processor is compliant with OpenGL ES that is widely used for standard API of embedded system. The proposed structure can be efficiently used in 3D graphics accelerator for mobile applications.

• The Mathematical Education
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• v.43 no.2
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• pp.177-186
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• 2004

In this paper, we introduce new functional definitions for school geometry based on DGS (dynamic geometry system) teaching-learning environment. For the vertices forming a geometric figure, we first consider the relationship between the independent vertices and dependent vertices, and using this relationship and educational considerations in DGS, we introduce functional definitions for the geometric figures in terms of its independent vertices. For this purpose, we design a new DGS called JavaMAL MicroWorld. Based on the needs of new definitions in DGS environment for the student's construction activities in learning geometry, we also design a new DGS based geometry curriculum in which the definitions of the school geometry are newly defined and reconnected in a new way. Using these funct onal definitions, we have taught the new geometry contents emphasizing the sequential expressions for the student's geometric activities.

• International Journal of Precision Engineering and Manufacturing
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• v.3 no.1
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• pp.43-48
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• 2002

This paper describes an automated computer-aided engineering (CAE) system for three-dimensional structures. An automatic finite element mesh-generation technique, which is based on fuzzy knowledge processing and computational geometry techniques, is incorporated into the system, together with a commercial FE analysis code, and a commercial solid modeler. The system allows a geometry model of interest to be automatically converted to different FE models, depending on the physical phenomena of the structures to be analyzed, i.e., electrostatic analysis, stress analysis, modal analysis, and so on. Also, with the aid of multilayer neural networks, the present system allows us to obtain automatically a design window in which a number of satisfactory design solutions exist in a multi-dimensional design parameter space. The developed CAE system is successfully applied to evaluate an electrostatic micromachines.

• Journal for History of Mathematics
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• v.15 no.1
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• pp.1-14
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• 2002

This paper treats the history of the fundament of projective geometry Especially we introduce the essence of the framework of Karl Chirstian von Staudt's ‘Geometrie der Lage’. Von Staudt used axiomatical method to bum the system of the projective geometry, and proved the fundamental theorem of projective geometry. And he handled imaginary elements (or the first time in synthetic projective geometry.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.4
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• pp.43-52
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• 1996

This paper describes interactive computer procedures for design the forming sequences in cold forging. This system is implemented on the personal computer and its environment is a commercial AutoCAD system. The programming language. AutoLISP, was used for the configuration of the system. Since the process of metal forming can be considered as a transformation of geometry, treatment of the geometry of the part is a key in process planning. To recognize the part section geometry, the section entity representation, the section coordinate-redius representation and the section primitive geometru were adopted. This system includes six major modules such as input module, forging design module, forming sequence design module, die design module, FEM verification module and output module which are used independently or in all. The sequence drawing wigh all dimensions, which includes the dimensional tolerances and the proper sequence of operations, can generate under the environment of AutoCAD. The acceptable forming sequences can be verified further, using the FE simulation.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.6 no.3
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• pp.247-254
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• 2006

Biometrics are getting more and more attention in recent years for security and other concerns. So far, only fingerprint recognition has seen limited success for on-line security check, since other biometrics verification and identification systems require more complicated and expensive acquisition interfaces and recognition processes. Hand-Geometry can be used for biometric verification and identification because of its acquisition convenience and good performance for verification and identification performance. It could also be a good candidate for online checks. Therefore, this paper proposes a Hand-Geometry recognition system based on geometrical features of hand. From anatomical point of view, human hand can be characterized by its length, width, thickness, geometrical composition, shapes of the palm, and shape and geometry of the fingers. This paper proposes thirty relevant features for a Hand-Geometry recognition system. This system presents verification results based on hand measurements of 20 individuals. The verification process has been tested on a size of $320{\times}240$ image, and result of the verification process have hit rate of 95% and FAR of 0.020.