• Proceedings of the KIEE Conference
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• 1992.07a
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• pp.347-350
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• 1992

In this note, we propose a method for designing a robot controller which can suppress the effects of both the model uncertainty and noisy velocity measurements. The controller is an output feedback compensator of which the constant gains are given in terms of a Riccati equation and a Lyapunov equation. The controller guarantees not only uniform boundedness but uniform ultimate boundedness. The stability result is local but the region can be arbitrarily enlarged at the expense of large control gain. The control law needs neither the exact knowledge of the physical robot parameters nor clean velocity measurements.

• Journal of Mechanical Science and Technology
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• v.19 no.2
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• pp.716-727
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• 2005

Comprehensive measurements for velocity and temperature fields have been conducted. A Micro PIV 2-color LIF system have been setup to measure the buoyancy driven fields in a 1-mm heated channel with low Grashof-Prandtl numbers [$86]. Fluorescence microscopy is combined with an MPIV system to obtain enough intensity images and clear pictures from nano-scale fluorescence particles. The spatial resolution of the Micro PIV system is $75{\mu}m\;by\;67{\mu}m$ and error due to Brownian motion is estimated $1.05\%$. Temperature measurements have achieved the $4.7\;{\mu}m$ spatial resolution with relatively large data uncertainties the present experiment. The measurement uncertainties have been decreased down to less than ${\pm}1.0^{\circ}C$ when measurement resolution is equivalent to $76\;{\mu}m$. Measured velocity and temperature fields will be compared with numerical results to examine the feasibility of development as a diagnostic technique.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3E
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• pp.126-131
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• 2002

Ultrasonic measurements are made in egg white to study the properties of the solution of the natural protein. The high-Q ultrasonic resonator method is used to get the ultrasonic absorption spectra over the range 0.2-10 ㎒ at 20℃. It is proportional to the 1.25th power of the frequency. The gelation process caused by heat is studied from the change in the velocity and the absorption. at 3 ㎒ using the pulse echo overlap technique over the range of 10-80℃. The absorption decreases with increasing temperature up to 60℃ where it turns up sharply and rapidly increases thereafter. The strong absorption in the gel region is described by the interaction between the solution and the network structure made of protein. Very slow variation in time elapse is observed after the temperature is quickly raised. It would be a real-time observation of the network building process and the characteristic time for the process is shown to be 400 min. A hysteresis phenomenon with respect to the temperature is observed. This phenomenon is associated with the memorizing effect of the network structure of protein of the gel.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.10
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• pp.1279-1286
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• 1999

In conventional GPS/DR integration schemes, the GPS position (or pseudo-range) information is used in calibrating DR sensors. In those schemes, however, an inaccurate calibration may degrade the position accuracy when the GPS measurement is not available. This paper presents a new integration scheme where the GPS velocity information is used in calibrating DR sensors. Also proposed is a new error model of DR sensors for calibrating the bias error and the tilt error in dynamic environments. The proposed model makes it possible that the errors of both the DR sensor parameters and the velocity are calibrated using the GPS carrier-based velocity(or the pseudo-range rate) measurement while the DR position error is calibrated using the GPS position measurement. Since the DR sensors are calibrated accurately, the positioning accuracy is drastically improved when the GPS measurements are unavailable.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.115-123
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• 2003

Simultaneous measurements of velocity and OH distribution were made using particle image velocimetry(PIV) and planar laser-induced fluorescence(PLIF) of OH radical in turbulent hydrogen nonpremixed flames with coaxial air. The OH radical was used as an approximate indicator of chemical reaction zone. The OH layer was correlated well with the stoichiometric velocity, $U_s$, instantaneously and on average. In addition, high strain-rate regions almost coincide with the OH distribution. The residence time in flame surface, calculated from the root-mean-square value of the radial velocity, is proportional to $(x/d_F)^{0.7}$. It is found that the mean value of principal strain rate on the OH layer can be scaled with $(x/d_F)^{-0.7}$ and therefore, the product of the residence time and the mean strain rate remains constant over all axial positions.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.9
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• pp.520-525
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• 2003

A robust controller for large space structures(LSS) is studied from passivity point of view. While velocity sensors are commonly used for proportional-derivative (PD) control law to stabilize large space structures, if the structure can be controlled without velocity measurements, it is desirable against the failure of velocity sensors and for the cost reduction of the sensing system. In a recent result a dynamic output feedback control law has been provided using only displacement measurements. This paper presents a passivity-based controller design method and provides an alternative stability analysis tool for the previous displacement feedback robust control law. The closed-loop system can be viewed as a feedback interconnection of a passivated large space structure (LSS) and a strictly positive real (SPR) system.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.60-63
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• 2009

In this letter we report on the carrier velocity of polycrystalline pentacene transistors as a function of electric field. We performed a series of measurements on devices with a range of channel lengths. At moderate electric fields (<$5{\times}10^5$ V/cm), the characteristics are similar to those of disordered or amorphous organic semiconductors. The highest velocities we have measured are near $6{\times}10^4$ cm/s at room temperature. We perform quasi-static and dynamic measurements to measure carrier velocity. These results fill an important void between experimental results that have been obtained with disordered/amorphous organic semiconductors and single crystals.

• Journal of the Korea Institute of Military Science and Technology
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• v.14 no.3
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• pp.372-379
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• 2011

Estimating underwater target state variables(position, velocity, course, etc) is necessary to counteract threatening targets. In passive sonar systems, conventional target motion analysis(TMA) techniques using bearing and frequency measurements of an underwater target are widely introduced. However, it is not clear how conventional TMA techniques can be used if some of frequency measurements are unavailable during parts of the scenario, partially unavailable frequency measurements are common in the ocean with complicated acoustic conditions where frequency measurements often come and go. This paper proposes a new TMA algorithm, which is robust to partially unavailable frequency measurements, using the frequency measurements fusion method.

• The KSFM Journal of Fluid Machinery
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• v.18 no.5
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• pp.26-32
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• 2015

This paper describes performance evaluation of design parameters, air velocity inside a pipeline and pressure along a pipeline, using experimental measurements in an automated vacuum waste collection system. Automatic robot having six cameras is introduced to analyze the internal pipeline conditions whether waste accumulates at the bottom of the pipeline or not. Throughout the experimental measurements of the pipeline having the various shapes, it is found that pressure and internal air velocity linearly increase along the pipeline from a waste inlet to a waste collection station while air density decreases due to the air compression effect with high pressure. Although air velocity inside the pipeline at a waste inlet keeps design velocity range between 20 m/s and 30 m/s, it is noted that air velocity near the waste collection station exceeds maximum design velocity of 30 m/s. Pressure increase per unit length is changed from 17.6 Pa/m to 18.9 Pa/m, which depends on the air velocity inside the pipeline. From the investigation inside the pipeline with CCTV loaded on an automated robot, waste accumulated at the bottom of the pipeline is mainly found at the downstream of a circular curved pipe, an inclined pipe and a bended pipe.

• The Bulletin of The Korean Astronomical Society
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• v.36 no.1
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• pp.52.2-52.2
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• 2011

The correlation between black hole mass and galaxy stellar velocity dispersion gives an important clue on the black hole growth and galaxy evolution. In the case of AGN, however, it is extremely difficult to measure stellar velocity dispersions in the optical spectra since AGN continuum dilutes stellar absorption features. In contrast, stellar velocity dispersions of active galaxies can be measured in the near-IR, where AGN-to-star flux ratio is much smaller, particularly with the laser-guide-star adaptive optics. However, it is crucial to test whether the stellar velocity dispersion measured from the near-IR spectra is consistent with that measured from the optical spectra. Using the TripleSpec at the Palomar 5-m Telescope, we obtained high quality spectra ranging from 1 to 2.4 micron for a sample of 35 nearby galaxies, for which dynamical black hole masses and optical stellar velocity dispersion measurements are available, in order to calibrate the stellar velocity dispersion in the near-IR. In this poster, we present the initial results based on 10 galaxies, with the stellar velocity dispersion measured in the H-band.