• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.2
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• pp.47-54
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• 1992

In this paper, a new extended JPDA (Joint Probabilistic Data Association) tracking algorithm which has more excellent performance than that of the conventional JPDA algorithm in case of the tracking of crossing targets is proposed. In the proposed extended JPDA algorithm, the velocity parameters as well as the position parameters are included to compute the association probabilities between tracks and measurement data. Then the tracking performance of crossing targets is improved and the track bias of parallel moving targets can be reduced. Accordingly, in this paper, the new extended JPDA algorithm for multitarget tracking is proposed and its good performance is shown through the computer simulation. And, tracking performance of extended JPDA algorithm is also compared with that of JPDA algorithm with our noise model.

• JSTS:Journal of Semiconductor Technology and Science
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• v.6 no.3
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• pp.206-209
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• 2006

This paper presents an analytical noise model for the drain thermal noise, the induced gate noise, and their correlation coefficient in deep-submicron MOSFETs, which is valid in both linear region and saturation region. The impedance field method was used to calculate the external drain thermal noise current. The effect of channel length modulation was included in the analytical equation. The noise behavior of MOSFETs with decreasing channel length was successfully predicted from our model.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.41.1-41.1
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• 2017

We present weak-lensing analysis of the merging galaxy cluster Abell 115 at z=0.197 based on Subaru i and V band images. As merging clusters often show, Abell 115's merging signatures include radio relics, double X-ray peaks, and large offsets between the cluster member galaxies and the X-ray distributions. A weak-lensing study provides underlying dark matter distribution, the key information to determine the complex merging scenario of the cluster. In this work, we present 2D mass reconstruction of the cluster, which reveals two distinct mass peaks consistent with galaxy distributions. We measure the first weak-lensing mass of each subcluster. Our weak-lensing total mass estimate is a few factors lower than the published dynamical mass obtained from velocity dispersion. This large mass discrepancy may be attributed to a significant departure from dynamical equilibrium. We also re-analyze the archival chandra data and find that the result is consistent with weak-lensing mass.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.10a
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• pp.161-164
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• 2002

Optical fiber vibrations sensors (OFVSs) and extrinsic Fabry-Perot interferometer (EFPI) were used in damage monitoring of fiber-metal laminates(FML). The optical fiber vibration sensor and EFPI were applied in order to detect and evaluate the strain, damage and failure of FML. Damages in composites, such as matrix cracks, delamination and fiber breakage may occur as a result of excessive load, fatigue and low-velocity impacts. Tensile test was performed with the measurement of optical signal and acoustic emission (AE). The signals of the optical fiber vibration sensor due to damages were quantitatively evaluated by wavelet transform. EFPI was less sensible to the damage signals compared with the optical fiber vibration sensor. It was found that damage information of comparable in quality to acoustic emission data could be obtained from the optical fiber vibration sensor signals.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.730-733
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• 2001

A computer aided design system for spur, helical, bevel and worm gears by using AutoCAD system and its AutoLISP computer language was newly developed in this study. Two methods are available for a designer to draw a gear. The first method needs the gear design parameters such as pressure, module, number of tooth, shaft angle, velocity, materials, etc. When the gear design parameters are inputted, a gear is drawn in AutoCAD system and maximum allowable power and shaft diameter are calculated additionally. The second method calculates all dimensions and gear design parameters to draw a gear when the information such as transmission, reduction ratio, rpm, materials and pressure are inputted. The system includes four programs. Each program is composed of a data input module, a database module, a strength calculation module, a drawing module, a text module and a drawing edit module. In conclusion, the CAD system would be widely used in companies to find the geometric data and manufacturing course.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.370-375
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• 2003

Optical fiber vibrations sensors (OFVSs) and extrinsic Fabry-Perot interferometer (EFPI) were used in damage monitoring of fiber-metal laminates(FML). The optical fiber vibration sensor and EFPI were applied in order to detect and evaluate the strain, damage and failure of FML. Damages in composites, such as matrix cracks, delamination and fiber breakage may occur as a result of excessive load, fatigue and low-velocity impacts. Tensile and indentation test was performed with the measurement of optical signal and acoustic emission (AE). The signals of the optical fiber vibration sensor due to damages were quantitatively evaluated by wavelet transform. It was found that damage information of comparable in quality to acoustic emission data could be obtained from the optical fiber vibration sensor signals.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.561-564
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• 2002

For the reduction of fuel consumption of high speed, the aerodynamic drag must be reduced. In early vehicle design process, it is very important to have information about aerodynamic characteristics of design models. In this phase CFD methods are usually used to predict the aerodynamic forces. But commercial programs using turbulence models cannot give a good agreement with experimental result and have also problems with convergence. PowerFLOW employs a new technology called DIGITAL PHYSICS, which provides a different approach to simulating fluids. DIGITAL PHYSICS uses a lattice-based approach (extended from lattice-gas and lattice-Boltzmann methods) where time, space and velocity are discrete. This discrete system represents the Wavier-Stokes continuum behavior without the numerical instability Issues of traditional CFD solvers, such as convergence. In this paper, aerodynamic performance of vehicles are simulated using PowerFLOW by Exa and results are compared with experimental wind tunnel data.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.733-736
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• 2002

The inside configuration of intake nozzle of vacuum cleaner greatly affects the dust-collection efficiency and acoustic-noise effect generated from flow separation Interaction between high-speed flow and internal structure. In order to improve the performance of the vacuum cleaner, flow fields inside the intake nozzles were investigated using flow visualization and FIV (Particle Image Vetocimetry) technique. The measurement to aerodynamic power, suction efficiency and noise level were also carried out. Valuable information was obtained from the experiments, revealing how to modify the intake nozzle. In this paper, the results of visualization, velocity distribution of flow fields, aerodynamic power, suction efficiency and noise level are discussed.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.83-88
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• 2002

This study is to provide the experimental information and basic data on heat transfer characteristics of horizontal liquid film driven by hot wind. Heat transfer characteristics of the liquid film in the rectangular duct was observed and the change of film temperature was measured. The experiments were carried out for a variety of parameter, such as feed water rate and velocity and temperature of feed air. From the observation and the measurement the general understanding of heat transfer characteristics for liquid film driven by hot wind was provided.

• Journal of Mechanical Science and Technology
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• v.16 no.1
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• pp.116-124
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• 2002

In order to investigate the soot formation and oxidation processes, we employed the two variable approach and its source terms representing soot nucleation, coagulation, surface growth and oxidation. For the simulation of the taxi-symmetric turbulent reacting flows, the pressure-velocity coupling is handled by the pressure based finite volume method. We also employed laminar flamelet model to calculate the thermo-chemical properties and the proper soot source terms from the information of detailed chemical kinetic model. The numerical and physical models used in this study successfully predict the essential features of the combustion processes and soot formation characteristics in the reacting flow field.