• Journal of Institute of Control, Robotics and Systems
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• v.22 no.3
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• pp.177-185
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• 2016

This paper presents a method to design a controller for active suspension with 1-DOF decoupled models. Three 1-DOF decoupled models describing vertical, roll and pitch motions are used to design a controller in order to generate a vertical force, roll and pitch moments, respectively. These control inputs are converted into active suspension forces with geometric relationship. To design a controller, a sliding mode control is adopted. Frequency domain analysis and simulation on vehicle simulation software, CarSim$^{(R)}$, show that the proposed method is effective for ride comfort.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.2
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• pp.148-162
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• 1996

Bonding wires for high frequency device packaging have dominant parasitic inductances which limit the performance of semiconductor lasers. In this paper, the inductance sof bonding wires are claculated by the method of moments with incorporation of ohmic loss, and the wideband modulation characteristics are analyzed for ddifferent wire lengths and structures. We observed the modulation bandwidth for 1mm-length bonding wire lengths and structures. We observed the modulation bandwidth for 1mm-length bonding wire is 7 GHz wider than that for 2mm-length bonding wire. We also observed th estatic inductance calculation results in dispersive deviation of the parasitic inductance and the modulation characteristics from the wideband moment methods calculations. The angled bonding wire has much less parasitic inductance and improves the modulation bandwidth more than 6 GHz. This calculation resutls an be widely used for designing and packaging of high-speed semiconductor device.

• Korean Journal of Computational Design and Engineering
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• v.8 no.4
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• pp.278-288
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• 2003

Presented in this paper is a numerical method for calculating the intersection points between Z-map vectors and the tool swept surface for circularly moving filleted-end mills. In numerically controlled(NC) machining simulation for large moulds and dies, a workpiece is frequently approximated as a set of z-axis aligned vectors, called Z-map vectors, and then the machining processes can be simulated through updating the Z-map with the intersection points. Circular motions are typically used for machining the free-form surfaces. For fast computation, we express each of intersection points with a single-variable non-linear equation and calculate the candidate interval in which the unique solution exists. Then, we prove the existence of a solution and its uniqueness in this candidate interval. Based on these properties, we can effectively apply numerical methods to finally calculate the solution of the nonlinear equation within a given precision. Experimental results are given for the case of a TV monitor and the hood of a car.

• Journal of the Ergonomics Society of Korea
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• v.13 no.2
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• pp.33-41
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• 1994

The paper presents a new scheme and a support system for the analysis sof hyman errors in nuclear power plants based on a cognitive model. We discusse the problems identified in current managerial analysis, and propose a new approach that frames the description of human activities according to a human decision making modle, so that it could provide a better reconstruction of a sequence of event suspected of involving human errors. This sophistcated approach becomes practical for the field application with the support of a computerized aiding system. The model-based event re-construction method is expected to enable the analysts to produce more informative reports, which in turn heop to derive appropriate counter- measures to reduce the possibility of the analyzed human errors.

• 제어로봇시스템학회:학술대회논문집
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• 1987.10b
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• pp.364-369
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• 1987

It has recently shown that a solenoid valve can be utilized in a hydraulic position-control system by discontinuous control methods. The objective of this study is to investigate the effects of solenoid valves on the response characteristics of a hydraulic position-control system by applying two kinds of discontinued control methods i.e., Simple On-Off (SOF) and Pusating On-Off(POF) controls. Three types of solenoid valves i.e. low-frequency, closed-center type (LF/C), high-frequency, closed-center type (HF/C), low-frequency, tandem-center type(LF/T) were used in this study. Effects of loading conditions and control parameters on the response characteristics were experimentally examined and compared each other. Pressure transients within the actuator were also studied.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.33A no.11
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• pp.105-111
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• 1996

We have invetigated the characteristics of thermal instability of Co-silicides annealed at 850$^{\circ}$C ~ 1000$^{\circ}$C for 10~90 minutes in a furance with N$_{2}$ ambient. In our experiments, Co-silicides and Co/Ti bilayer silicides were formed by depositing (Co, Ti) films on the clean Si substrates in an E-beam evaporator and performing the RTA annelaing. The sheet resistances of Co-silicides formed form Co exhibited the nearly constant value under the post-annealing time above 900$^{\circ}$C showing the increase of 30% and 60% under the conditions annealed at 900$^{\circ}$C and 1000$^{\circ}$C for 30minutes. On the other hand, there were no remarkable changes in the sheet resistance sof Co-silicides formed form Co/Ti bilayer under the post-annealing conditons below 1000$^{\circ}$C.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.4
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• pp.12-24
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• 1997

An intelligent steering control system is designed for the steering control of a 4 wheel drive (4WD) electric vehicles without steering mechanism, where the vehicle is assumed to have 3 degree of freedom and input-output feedback linearization is employed. Especially, a fuzzy-rule-based side force estimator is suggested to avoid uncertain highlynonlinearexpression sof relations between side forces and their factors. Also, aneural-network-based predictive compensator is additionally utilized for the vehicle model to be correctly controlled with unstructured uncertainties. The proposed overall control system is numerically shown to be robust against drastic change of the external environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.4
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• pp.164-170
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• 1996

Among after treatment devices which reduce exhaust gas of diesel engine, diesel oxidation catalyst(DOC) with high reduction efficiency for gaseous matter and particulate matter is now being studied actively. In this study, an experiment was conducted to analyze the effects on factors of oxidaton characteristics and conversion efficiency of DOC. We tested to estimate change of engine performance whether a 11,000cc diesel engine equipps with DOC or not. We conducted test to estimate the reduction efficiency of exhaust gas in P-5 mode, in D-13 mode of heavy duty diesel regulation mode and in somoke opacity mode for two samples and also we conducted test to analyze the effects about both exhaust gas velocities 1,100rpm and 2,200rpm

• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.179-185
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• 1995

The fusion rates of nuclear transplant embryos with various DC voltage were 55.6-79.2%. The significantly higher fusion rates of nuclear transplant embryos were achieved at the electric field strenght of DC 1.0-2.0kV/cm(72.0-79.2%) than DC 0.75kV/cm(55.6%, P<0.05). No significant differences in the percentage of embryos that cleaved(48.1, 55.4 and 42.6% respectively) and the percentage of cleaved embryos that developed to morulae/blastocyst(1.9, 5.3 and 1.9% respectively) could be found among the three types of in vitro culture system (Granulosa cell, BOEC co-culture and SOF, P>0.01). The age of the recipient cytoplast(30 vs 40hr) had no effect on the fusion rates and the rates of cleavage development(36.9 vs 44.1%, P>0.01).

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.6
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• pp.1282-1289
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• 1988

It has recently shown that a solenoid valve can be utilized in a hydraulic position-control system by discontinuous control methods. The objective of this study is to investigate the effects of solenoid valves on the response characteristics of a hydraulic position-control system by applying two kinds of discontinuous control methods i.e., Simple On-Off(SOF) and Pulsating On-Off(POF) controls. Three types of solenoid valves i.e., low-frequency, closed-center type(LF/C), low-frequency, tandem-center type(LF/T) were used in this study. Effects of loading conditions and control parameters on the response characteristics were experimentally examined and compared each other. Pressure transients within the actuator were also studied.