• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1268-1275
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• 2003

In this paper, a compact 3-DOF mobile microrobot with sub-micron resolution is presented. It has many outstanding features : it is as small as a coin ; its precision is of sub-micrometer resolution on the plane ; it has an unlimited travel range ; and it has simple and compact mechanisms and structures which can be realized at low cost. With the impact actuating mechanism, this system enable both fast coarse motion and highly precise fine motion with a pulse wave input voltage controlled. The 1 -DOF impact actuating mechanism is modeled by taking into consideration the friction between the piezoelectric actuator and base. This modeling technique is extended to simulate the motion of the 3-DOF mobile robot. In addition, experiments are conducted to verify that the simulations accurately represent the real system. The modeling and simulation results will be used to design the model-based controller for the target system. The developed system can be used as a robotic positioning device in the micromanipulation system that determines the position of micro-sized components or particles in a small space, or assemble them in the meso-scale structure.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.804-809
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• 2001

Optimal design of a portable structure which supports impact loading is presented. The structure requires impact loading capability, stiffness and minimum weight for portability. A collapsible tripod structure with locking mechanism is suggested. Taguchi method has been used to identify the most important design variables and the initial design. Subsequent optimization yields additional weight reduction under stress and displacement constrains.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.42-44
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• 2001

This paper proposes impact vibration theory of magnetic contactor moving mechanism and correlation test the bouncing time with the spring load. Mechanical and electrical lifetime is under the influence of impact vibration of magnetic contactor moving mechanism. In shortage of technique, we have experienced many difficulties in magnetic contactor development. By this research, we analyzed total moving mechanism and applied results to optimum 4p magnetic contactor development.

• Journal of Environmental Science International
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• v.2 no.4
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• pp.245-254
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• 1993

This paper attempts to analyze the institutionalization process of Environmental Impact Assessment(EIA) system within the context of Korean environmental policy. The implementation of EIA in the 1980's was not seriously considered by other government agencies and was sometimes degraded as mere formality due to the inherent problems of the system. With viewing the theory and practice of EIA in Korea, this paper argues that it is essential to reinforce ex post facto management incorporate the participation of residents of concerned areas, upgrade the validity of assessment by selecting a credible assessment-agenices and develop the required technologies. Finally, this paper acknowledge the necessity of devising the mechanism to reconcile the conflict between the regional interest and the national interest.

• Journal of the Korean Operations Research and Management Science Society
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• v.29 no.3
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• pp.99-109
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• 2004

In this paper, we investigate the impact of window mechanisms on end to end delay in a series of nodes with constant service times. It is shown that arbitrary combinations of window mechanisms, each applying to an arbitrary subset of data, can be embedded on the nodes without affecting the departure instants from the system if the windows are at least as large as the number of nodes spanned. The window mechanisms are shown to have no impact on the average end to end delay of data. As the condition on the windows is a minimal necessary requirement for full parallelism, the results show that the transparent operation from viewpoint of data transmission can be achieved with minimal resources.

• Journal of the Korean Society for Precision Engineering
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• v.23 no.5 s.182
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• pp.170-176
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• 2006

Multi-layered laminate made of ceramic/composite have been developed to prevent penetration by high velocity impact. In this study, three-layered plates consisted of 1) cover layer (glass fiber reinforced polymer), 2) $Al_{2}O_{3}$, ceramic plate, and 3) backing plate (glass fiber reinforced polymer) were fabricated with various conditions and tested for their ballistic protection characteristic. The ceramic composite laminates, with thin backing plate, were completely penetrated by armor piercing projectile. The plate with inserted rubber between ceramic and backing plate showed excellent ballistic protection, though completely penetrated by the second shoot.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.129-132
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• 1996

There is a tendency nowadays to produce increasingly miniaturized electronic equipment which incorporate parts that have to be precisely positioned, like lenses, heads and CCD's in scanners, printers, copiers, VCR's, optical fiber modules, etc. In contrast to the production process of precision parts, which is currently being carried out automatically, the assemblage process is still being performed by specially skilled technicians. The assemblage process comprises normally the following steps: firstly, the parts are roughly positioned and partially fixed, secondly, the parts are manually nudged towards the target position and finally glued, screwed or welded. This paper presents a system that uses six piezo Impact Drive Mechanisms for accurate micro positioning within three degrees of freedom (lateral and longitudinal translation and rotation). The system is designed to positioning a printed circuit board with an accuracy better than 3 .mu.m (for translations), 5 mrad (for rotation).

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.422-428
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• 2005

In this paper, the contact force between two colliding bodies is modeled by using Hertz's force-displacement law and nonlinear damping function. In order to verify the appropriateness of the proposed contact force model, the drop type impact test is carried out for different impact velocities and different materials of the impacting body, such as rubber, plastic and steel. In the drop type impact experiment, six photo interrupters in series close to the collision location are installed to measure the velocity before impact more accurately. The characteristics of contact force model are investigated through experiments. The parameters of the contact force model are estimated using the optimization technique. Finally the estimated parameters are used to predict the impact force between two colliding bodies in opening action of the magnetic contactor, a kind of switch mechanism for switching electric circuits.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.121.2-121.2
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• 2005

• Elastomers and Composites
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• v.28 no.4
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• pp.283-292
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• 1993

The morphology and impact strength of alloys of high density polyethylene(HDPE) and nylon-6(PA) with modified $ethylene-{\alpha}-olefin$ copolymer(OCP) as compatibilizer and impact modifier were measured by the scanning electron microscope(SEM) and the notched Izod impact test(and the high rate impact test), respectively. HDPE is incompatible with PA and specimens obtained from simple mechanical mixing show the inferior properties. However, it was indicated that OCP played roles of not only impact modifier but also compatibilizer. High rate impact test results were different from those of the notched Izod impact test, but in both tests OCP was effective for HDPE/PA blends. From SEM observation, the size of the dispersed phase in alloys prepared with OCP is much smaller than that of alloys without OCP and the interfacial adhesion of alloys prepared with OCP is also better. Toughening mechanism of polymer blends was discussed by combining the morphology analysis with mechanical and thermal properties.