• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.554-557
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• 1993

The error analysis for the Time-in-Flight Laser Range Finder with Multiple Tone Amplitude Modulation relevant to the phase detection error is made. The distance can be estimated to solve the formulate which express the relationship between the absolute distance from the range finder to the object and the wavenumbers and the phases of the modulated waves by the optimization technique. The main cause of the estimation error can be considered as the phase detection error induced from the amplitude modulator and the phase detector. To clarify the phase detection error and the optimal amplitude frequency set, the numerical analysis are made.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.502-504
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• 2003

The main objective of this study is to examine the effectiveness of newly available high spatial resolution satellite images, in evaluating vegetation environment of the urban areas. In doing so, we have used satellite images from QuickBird and selected some areas of Fukuoka City, Kyushu Japan, as study area. The results of the study revealed that, high resolution images are more effective in close monitoring of the vegetation status and green plants should be planted in open spaces and roofs of urban areas to increase vegetation, which will in turn act as a remedy to reduce heat island phenomenon.

• Journal of Power Electronics
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• v.9 no.3
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• pp.430-437
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• 2009

This paper presents the dynamic characteristics of buck and buck-boost dc-dc converters with digital filters. At first, the PID, the minimum phase FIR filter and the IIR filter controls are discussed in the buck dc-dc converter. Comparisons of the dynamic characteristics between the buck and buck-boost converters are then discussed. As a result, it is clarified that the superior dynamic characteristics are realized in the IIR filter method. In the buck converter, the undershoot is less than 2% and the transient time is less than 0.4ms. On the other hand, in the buck-boost converter, the undershoot is about 3%. However, the transient time is approximately over 4ms because the output capacitance is too large to suppress the output voltage ripple in this type of converter.

• Elastomers and Composites
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• v.34 no.5
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• pp.383-390
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• 1999

Functionally graded polyurethane elastomers PUEs/grad. Poly(dimethylammoninum ethylacrylate bromide)(PDMAEA) were prepared by the method of electrophoresis. Results of elemental analysis showed that concentration of PDMAEA had gradient across the thickness(2mm) of the base PUEs. The modified PUEs(PUEs/grad. PDMAEA) containing high concentration of PDMAEA displayed low degree of swelling in benzene which was poor solvent for PDMAEA, and high degree of swelling in water which was good solvent. For the each layer of modified PUEs, glass transition temperature, dynamic storage modulus were stooled by DSC, Rheovibron DDV-IIC dynamic viscoelastomer. The chemomechanical properties of modified PUEs was explored by the electric-stimulus.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.545-548
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• 2004

In Japan for protecting the slides of steep sloped areas covering the face of slopes by sprayed mortar became popular since 1970s. But, these mortar walls are getting older now. In this background, this study aims to find ways to develop a diagnostic technique of these faces of slope without physically contacting or destroying them. In doing so, we have used heat infrared imaging processing method and developed a simulation model to predict the weak portion of the wall. The results revealed that, by following the model vacuum of mortar wall can be detected having thickness up to 15cm.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.529-532
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• 2004

This study aims at examining the environment of waterfronts by applying satellite remote sensing technique. In doing so we have selected Inchon International Airport, Korea as a case. As a method of the study, Normalized Difference Vegetation Index (NDVI) and land cover changes are estimated in and around Inchon International Airport. As a result of the study, we have found vegetation's change in the Airport and variation of neighborhood city by building of waterfront.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.3-6
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• 2004

This study aims to estimate, in monetary figures, the environmental value of recreational theme park- Huis Ten Bosch (HTB), located in Nagasaki Prefecture, Japan, through the integration of both contingent valuation method (CVM) and remote sensing. In the analysis, we have estimated the environmental value of HTB through CVM. Then, we have compared this amount with the valuation made by using remote sensing. The results of the study would provide the interest groups some monetary base, to value the worth of environmental restoration activities undertaken by HTB.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.346-349
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• 1994

This paper is concerned with a motion control of a manipulator under parametric uncertainties and external disturbances. The parametric uncertainties are regarded as internally generated disturbances in the manipulator. Based on this idea, we formulate a model reference control problem with desired disturbance attenuation. The solution of this control problem not only reduces the worst-case effect on tracking error due to internal and external disturbances (combined disturbances) as much as possible, but also achieve optimal tracking when perturbations are absent. In order to solve the control problem which is formulated in this paper we reduce it to a constrained minmax cost control problem. A differential game theory is used to treat this constrained minmax cost control problem. The differential game theory leads to a sufficient condition for the global solvability of the model reference control problem with desired disturbance attenuation.

• International Journal of Fluid Machinery and Systems
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• v.4 no.2
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• pp.229-234
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• 2011

For Lift-type Vertical Axis Wind Turbine (VAWT), it is difficult to evaluate the performance through the scale-model wind tunnel tests, because of the scale effect relating to Reynolds number. However, it is beneficial to figure out the critical value of Reynolds number or minimum size of the Lift-type VAWT, when designing this type of micro wind turbine. Therefore, in this study, the performance of several scale-models of Lift-type VAWT (Reynolds number : $1.5{\times}10^4$ to $4.6{\times}10^4$) was investigated. As a result, the Reynolds number effect depends on the blade chord rather than the inlet velocity. In addition, there was a transition point of the Reynolds number to change the dominant driving force from Drag to Lift.

• Structural Engineering and Mechanics
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• v.6 no.8
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• pp.939-953
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• 1998

Vibration, buckling and dynamic stability of a cantilever rectangular plate subjected to an in-plane sinusoidally varying load applied along the free end are analyzed. The thin plate small deflection theory is used. The Rayleigh-Ritz method is employed to solve vibration and buckling of the plate. The dynamic stability problem is solved by using the Hamilton principle to drive time variables. The resulting time variables are solved by the harmonic balance method. Buckling properties and natural frequencies of the plate are shown at first. Unstable regions are presented for various loading conditions. Simple parametric resonances and combination resonances with sum type are obtained for various loading conditions, static load and damping.