• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.91-96
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• 2008

As a remarkable reduction of the vehicle noise, the important of tire noise which is generated from the vehicle and the necessity of the research for the noise reduction is being emphasized. In this study, the road noise which is excited by the interaction between tire and road has been studied. The subjective test(feeling test) according to SAE J1060 rating scale is applied to the evaluation of the road noise. The combination of the several tires and vehicles are made to consider the effect of the vehicle suspension and the tire structure for road noise. The vehicles with 3-different suspension system are applied to road noise test and the eight kinds of tires are selected. As the results, the effects of the vehicle suspension and tire structure which affects on road noise are investigated.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.124-131
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• 2008

There are many factors which affect the acoustical properties of a micro-speaker. Among the factors, the shape of the diaphragm is considered in this study. As an investigating method, the finite element methods and measurement techniques applied to study the acoustical properties according to diaphragm shape. In order to vary the stiffness of the diaphragm, the some patterns of comb teeth, such as the angle and the number of comb teeth, are applied to diaphragm. We can confirm that the change of the stiffness by the changing diaphragm shape affects the vibration and sound properties of the speaker. As a result, the reduction of the angle of the comb teeth increases the diaphragm stiffness and shifts the resonance frequency to a higher frequency range. The number of the comb teeth is related to the stiffness of the edge part.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.784-789
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• 2012

Ultrasonic Cutting which uses a tuned blade resonant in a longitudinal mode, has been used to cut a range of materials from confectionery, baked products and frozen foods, to wood, bone, foams and composites. The Blade design typically uses finite element analysis, and it could be predicted vibration mode, gain and amplitude uniformity of the blade tip at resonant frequency. In this paper, FEA used to predict the vibration characteristic of the blade, and then the results were verified by analysis system of resonant frequency using the processed blade. The crack of the blade which is predicted from FEA was compared with the crack occurred by cutting experiment of rubber materials using the processed blade.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.377.1-377
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• 2002

Recently, an optical disc system has been proposed using blue laser diode, high NA objective lens and groove only disc structure. A new method is needed to readout CD and DVD in the blue system. In order to readout CD and DVD in HD-DVD system, we adopted dual-lenses actuator in consideration of optical utilization efficiency, optical performance and insurance of sufficient W.D (working distance). (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.778-781
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• 2008

The aim of this paper is to analyze the dynamic responses of pantograph-overhead contact line coupled system by using a condition monitoring system. The monitoring items are strain, vertical displacement and acceleration of a contact wire. Both strain and vertical displacement in the contact wire depends on uplift force and train velocity. Measurement of acceleration shows that the passage of the pantograph gives an impact force to a hard point on a contact wire.

• Journal of the Korean Chemical Society
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• v.30 no.2
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• pp.224-230
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• 1986

Dodecyltrimethylammonium bromide (DTAB) was examined as a counter-ion in the separation of aromatic sulfonic acids on alkylmodified silica (ODS) column by reversed-phase ion-pair chromatography. The capacity factor of acids was investigated and separation was attempted. The capacity factor of samples was influenced by the several factors such as a concentration of counter-ion, concentration of methanol, kinds and concentration of electrolyte in mobile phase as well as kinds and position of functional group in samples. Some mixtures of samples were able to be separated under optimum condition.

• Journal of IKEEE
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• v.24 no.2
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• pp.669-672
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• 2020

In this paper, we analyzed the characteristics of cyber attacks and major threat scenarios that could occur around intelligent building management Systems(IBS) by cyber attack security threats against cyber physics systems. Generally determined that lowering the likelihood of aggression against predictable threats would be a more realistic approach to attack response. The countermeasures against this need to be applied to multi-layered defense systems, and three alternatives were proposed: preliminary cyber safety diagnosis for protection targets and the establishment of mobile security control systems.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.337-342
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• 1992

The load distribution problem of two cooperating robots grasping one object is studied. The optimal joint torque needed for the desired motion is obtained by using a new objective function. A new objective function is defined for the minimization of joint torque effort and internal force. The optimal solution can be found by geometrical approach and analysis using the concept of force ellipsoid. Simulation results are presented with 6DOF PUMA robots.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.491-496
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• 1992

An analytic solution approach to the time-varying obstacle avoidance problem is pursued. We formulate the problem in robot joint space(JS), and introduce the view-time concept to deal with the time-varying obstacles. The view-time is a set of continuous times in which a time-varying obstacle is viewed and approximated by an equivalent stationary obstacle. The equivalent stationary obstacle is transformed into the JS obstacle. In JS, the path and trajectory avoiding the JS obstacle is planned.

• Journal of Institute of Control, Robotics and Systems
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• v.1 no.2
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• pp.71-77
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• 1995

The control effectiveness and disturbance suppressibility are mainly governed by a left eigenstructure of a system. In this paper, a control algorithm which uses an output feedback eigenstructure assignment scheme is proposed in order that a desired closed-loop system has the specified degree of controllability and/or degree of disturbance suppressibility. To do this, a modal and a gross disturbance suppressibility measures are proposed. A modified version of Hamdan and Nayfeh's modal controllability measure is also presented. The validity and usefulness of the proposed measures and the controller design algorithm are illustrated by designing a controller for a third-order system as an example.