• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.355-358
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• 2003

Recently, micro forming process technology have been developed since the size of machine parts become the crucial factor for minimizing of products in general electronic products. Most small machine parts consist of gear and rotation axis and the wear by mechanical contact is known as the primary factor for life reduction of high precision machine part. Lots of studies for mechanical wear and friction have been reported and many researches of MEMS technology have been studied recently. But just few studies for wear of micro or milli sized machine part have teen implemented. In this research, the wear equation is suggested according to the contact shape of axial part in micro or milli sized machine part. And wear analysis model which can predict the magnitude of wear through this suggested equation with numerical analysis program.

• Structural Engineering and Mechanics
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• v.13 no.4
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• pp.437-453
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• 2002

In this paper, dynamic stiffness and flexibility for circular membranes are analytically derived using an efficient mixed-part dual boundary element method (BEM). We employ three approaches, the complex-valued BEM, the real-part and imaginary-part BEM, to determine the dynamic stiffness and flexibility. In the analytical formulation, the continuous system for a circular membrane is transformed into a discrete system with a circulant matrix. Based on the properties of the circulant, the analytical solutions for the dynamic stiffness and flexibility are derived. In deriving the stiffness and flexibility, the spurious resonance is cancelled out. Numerical aspects are discussed and emphasized. The problem of numerical instability due to division by zero is avoided by choosing additional constraints from the information of real and imaginary parts in the dual formulation. For the overdetermined system, the least squares method is considered to determine the dynamic stiffness and flexibility. A general purpose program has been developed to test several examples including circular and square cases.

• Transactions of Materials Processing
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• v.9 no.6
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• pp.574-581
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• 2000

A vertically-walled auto-body part is one of the most difficult stamping parts because of angle change, wall curl, and twisting of the blank after springback as well as fracture and wrinkle. In this study, computational simulations of the vertically-walled auto-body part are carried out focusing on angle change, wall curl, and twisting after springback. Binderwrap blank shape is used in forming analysis for precise initial contacts between punch and blank. An adaptive mesh method is used in springback analysis for precise calculation of bending moments. In springback analysis, the differences of 2 and 3 dimensional analysis are compared and the effects of blank holdig force and friction coefficient are evaluated. In order to verify the validity of simulation results, they are compared with measured ones. The predicted thickness distribution and formed shape are agreed well with those of the measurement. The Predicted springback amount is less than that of the measurement.

• Proceedings of the KOSOMBE Conference
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• v.1993 no.05
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• pp.113-115
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• 1993

In this paper, we proposed a speech support system of personal computer for the blind. The system is consist of hardware part and software part. The hardware part are consist of personal computer and sound card. The software part are consist of sound driver system, character table and sound output algorithm. This system can recognize inputted characters from keyboard and program produced character strings.

• Journal of Korean Institute of Industrial Engineers
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• v.17 no.2
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• pp.1-16
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• 1991

This paper deals with some critical activities of CAPP system such as generation of part description database, part feature recognition, process and operation selection, and sequencing method for turning operation of symmetric rotational parts. The part description database is generated by data conversion module from CAD data, and the part feature is recognized by using both pattern primitives and feature recognition rules. Machining processes and operations are selected based on machining surface features and its sequence is determined by rules acquired from process planning expert. AutoCAD is employed as CAD system and computer program is developed by using Turbo-C on IBM PC/AT compatible system.

• Journal of Institute of Control, Robotics and Systems
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• v.12 no.11
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• pp.1111-1118
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• 2006

This paper covers topics related to the investigations for the problem of sensorless vibratory orienting of polygonal parts with high probability through dynamic simulation. The author's program for mechanical systems with changing topologies was experimentally validated and was used as a simulation and design tool for motion behaviors of the vibratory parts-orienting system in the dynamic environment. A flat level vibrating bar is proposed as a means of orienting parts. Dynamic manipulation, in which a part is repeatedly caught and tossed by the bar without sensing, forms the fundamental manipulation strategy. This paper presents how to plan vibratory manipulation strategies that can orient a small rigid polygonal part using interaction between the part and the vibrating bar without requiring sensing. The planned motion strategies have been experimentally validated to show how the dynamic simulation can be used to find favorable vibration parameters for a given part without knowledge of their initial orientations.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.152-155
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• 1993

Protective Relay in power system play a prominent part in minimizing power delivery interruptions and help to get a fast and secure restoration when a failure occurs. In order to meet the higher functional requirements in power system, the performance tests on response characteristic of protective relay is essential to ensure reliability. The purpose of this study is as follows: In order to evaluate performance of protective relay, it is intended to develop performance of digital protective relay simulator which is composed of digital protective relay part, behaviour analysis part, waveform generation part and simulation program to simulate pour system in detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5323-5329
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• 2013

Many companies have tried to develop the horizontally vibrating linear motor, for sliming the smart phone. Mathematical modeling and analysis is one of method to simulate the dynamic performance of the horizonatally vibrating linear motor. However, the horizontally vibrating linear motor vibrates in twisting mode because there are two kinds of force acting on the vibrating part. One is are the horizontal force by Lorentz force. The other is the vertical force by attraction force between magnet of vibrating part and bracket and the gravity force of vibrating part. However, those are very difficult to be included in mathematical modeling which generate the simulation errors. In this paper, we perform MFBD (multi flexible body dynamics) simulation using commercial dynamic analysis program "DAFUL". In our new model, the force effects those are neglected in mathematical model, are included. For the verification, the simulation results are compared with the experiment results with manufactured prototype.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.237-241
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• 1987

In this paper, the BTR (Behind the Tape Reader) type communication unit which interfaces the IEBM PC/XT to the FANUC 5M NC controller is developed, making it possible to send NC part program from the memory of IBM PC/XT to the NC controller. As an example of integration of CAD and CAM technologies, the machining of a two dimensional hand-written free line which incorporates the processes of geometric data acquisition using a digitizing tablet, automatic part programming and control of NC milling machine operation is demonstrated.

• International Commerce and Information Review
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• v.11 no.4
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• pp.289-312
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• 2009

Under the circumstance of increasing international trade volumes and limitation of customs human resources, it is necessary to shift the customs' revenue collection activities and audit method from a transaction-based approach to an account-based approach. Thus, in 1997, U.S. Customs services established the Account Management Program. The Account Management Program is designed to increase importer compliance and improve customer service through one-on-one interaction with business entities and a designated Customs representative(Account Manager). The Account Management Program is a comprehensive process that includes the following stages and activities ; selection of a potential Account, establishment of the Account, management of the Account. In 2009, Korea Customs service introduced and executed the Account Management Program. But owing to its early stages, Korea Customs service does not suggest effective direction of development of the AM program. So I can propose the following improvements of the Account Management Program in Korea. Firstly, the Account Managers have to be assigned more traders than AEOs(Authorized Economic Operators). Secondly, it is necessary that Customs service appoints part-time port Account Managers to help more traders to improve customs compliance. Thirdly, thought should be given as to Account can be expanded to encompass both small and medium enterprises(SME) by providing customs brokers managing their customs business on the behalf of the SME with the Account Managers. Lastly, Customs service has to establish performance measures and action plan for the Account Management Program.