• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.8
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• pp.67-74
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• 2004

In this paper, a 3.3V 8-bit 500MSPS based on an interpolation architecture CMOS A/D converter is designed. In order to overcome the problems of high speed operation, a novel pre-amplifier, a circuit for the Reference Fluctuation, and an Averaging Resistor are proposed. The proposed Interpolation A/D Converter consists of Track ＆ Hold, four resistive ladders with 256 taps, 128 comparators, and digital blocks. The proposed A/D Converter is based on 0.35um 2-poly 4-metal N-well CMOS technology. The A/D Converter dissipates 440 mW at a 3.3 Volt single power supply and occupies a chip area of 2250um x 3080um.

• Applied Science and Convergence Technology
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• v.24 no.6
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• pp.257-261
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• 2015

We report on GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) that can cover the spectral range of $3.6-25{\mu}m$. One advantage of the GaAs QWIPs is the wavelength tenability as a function of their structural parameters. We have performed a systematic calculation on the detection wavelength of a typical $GaAs/Al_xGa_{1-x}As$ multi-quantum-well photodetector, with the aluminum mole fraction (x) of $Al_xGa_{1-x}As$ barrier in the range of 0.15-0.43 and the quantum-well width range from 30 to 60 $60{\AA}$. Design and fabrication of a QWIP based on $GaAs/Al_{0.23}Ga_{0.77}As$ structure with $37{\AA}$-thick well width has been carried out. The calculated operation wavelength of the QWIP is in a good agreement with the experimental data taken by photo response and activation energy calculation from thermal quenching of integrated photoluminescence.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.12
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• pp.1249-1253
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• 2010

As personal computers have been recently improved in performance, the multi tasking of running several applications at the same time has been generalized. Since only one task space is provided for performing such tasks on Windows operating system, a number of computer users feel inconvenient. In this paper, we propose a 3D Virtual Desktop System which can show a process of switching task spaces in 3D motion using DirectX. The proposed system can provide a computer user with more task spaces and the intuitive UI(User Interlace) such as Compiz of Linux.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.1
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• pp.91-98
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• 2008

One of the two spindles in the X-lift fractured suddenly during normal operation. The fracture occurred at the notch where the bending moment might be the maximum. Macrofractographic features associated with rotating-bending fatigue are evident on the fracture surface. The 3-D finite element analysis of the X-lift reveals that the spindle rotated under bending. The measured surface strain of the spindle varies cyclically as the spindle rotates. It supports that the spindle rotated under bending. The X-lift is not perfectly symmetrical with respect to both the horizontal and the vertical plane. The slightly unsymmetrical deformation can cause the bending of the spindle.

• Journal of Food Hygiene and Safety
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• v.18 no.1
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• pp.14-24
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• 2003

Two aims of the present study were the evaluation of hygienic, microbial safety on food services of elementary schools in Western Gyeongnam province, and then, the construction of database for the SSOP (Sanitation Standard Operation Procedures) practice. A total of 98 samples were collected from drinking water, waterworks, kitchen utensils, kitchen equipments, employees and cooked foods. Total bacteria was counted and pathogenic bacteria such E. coli, salmonella, yersinia, vibrio parahaemolyticus and staphylococcus were identified based on the biochemical analysis. Following are the results: the number of bacteria showed from 1.0x10$^2$CFU/ mL to 1.0x10$^{6}$ CFU/mL in most samples, which the level exceeds normal range. Over 1.0x10$^{5}$ CFU/ml bacteria were observed from the kimchi in 4 places (B, C, D, E), because cooked food such as kimchi had not been heated. As a rule, the bacterium level in place B was higher than that in any of the other places. E-coli were isolated from kitchen knives (C, E) and Kimchi (E): staphylococci were isolated from drinking water (A), hands (D), refrigerator (E) and apron (E). But, salmonella, vibrio and yersinia were not detected in anywhere. In conclusion, the presence of bacteria and pathogenic agents in school food service was closely related to hygienic practice. For that reason, it is necessary to have more systematic and efficient management in order to enhance the food safety.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.334-338
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• 2004

KTX has started commercial service from Seoul to Busan and Mokpo since April 1, 2004. The service line is composed of new-high speed line and conventional line. Before KTX is runs, the maximum operational speed on conventional line was 140km/h. In order to reduce the traveling time, operation speed of KTX must be increased on the conventional line. So, we performed test running with prototype HSR-350x and verification of safety was made in $10\%$ speed-up. Korean High Speed Train HSR-350x) was developed by G7 - R&D project. In this study, in safety aspect, several technical reviews are introduced and the possibility for reduction of traveling time is investigated on the conventional line by using HSR-350x.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.735-737
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• 2016

In this paper, we conducted a test of the 3D printer injection method and LSU (Laser Scanning Unit) feature a fusion of the polygon mirror scanning system that is the core mechanism operation for 3D printers for office laser printers SLA system. These tests ensure that the laser was operating and control well was confirmed that a certain point is output to the X-axis by means of a laser module and a polygon mirror. And confirmed after the F-theta lens is incident on the fixed laser power of the beam, and correction according to the correction beam on the mirror reflection was confirmed jineunji the focus according to the Z-axis upper plate.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2000.10a
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• pp.189-195
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• 2000

New concept of LNG-FPSO ship with moonpool and bilge step in bottom is considered and investigated in the point of motion reduction and sloshing phenomena of the cargo and operation tanks. The cargo capacity of the ship of which principle dimensions is L x B x D x t(design) =270.0 x 51.0 x 32.32 x 13.7(m) 16K at 98% loading condition. The two moonpools and rectangular step at bilge part are setted up specially for getting the effect of motion decrease. For the motion analysis, linearized three dimensional diffraction theory with the simplified boundary conditions is used. The six-degree of freedom coupled motion responses are calculated for the LNG-FPSO ship. Viscous effects on the roll motion responses of a vessel are taken into account in this calculation program using an empirical formula suggested by Ikeda, Himeno and Tanaka is used. The case study for the moonpool size had been carried out by theoretical estimation and experimental method. For the optimization of the moonpool size and effect of the step, 9 cases of its size and with and without step are considered. From the results of calculation and experiment, it can be concluded that this designed LNG-FPSO ship have possibility to carry out her missions in the rough sea as for the owner's demand waves condition. The motion responses, especially roll motion, for the designed LNG-FPSO ship are much lower than those of another drillship and shuttle tanker and limit criterions are satisfied. For the check of the cargo tank and operation tank sizes we have performed sloshing analysis in the irregular waves which focuses on the pressure distribution on the tank wall and the time history of pressure and free surface for No.2 and No5. tanks of LNG-FPSO with chamfers. Finally we got the tank size which has no resonance and no impact pressure in all filling in the bow quartering and beam sea.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.3
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• pp.130-135
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• 2006

There have been experiments dealing with the possibility of the actualization of the ANC system by means of operating the DSP adaptation filter. This filter is composed of various filters(including X-LMS algorithm, Filter-U algorithm, and Full-Feedback-Filter-U algorithm) that use ventilation fans and loudspeakers as a primary source in a circular duct as an experimental device. In this operation, the ANC system using the X - LMS algorithm was found to be more effective in reducing noise than without such system. When applying the input signal of the DSP board Full Feedback-Filtered-U algorithm system while having in mind that the additionally installed second control signal was gone through feedback and mixed into the detection microphone installed near the ventilation fan when using the first ventilation fan, the system was not emitted, but maintained stable during the operation of the control filter. At this point, noise tended to decrease at a maximum of l0dB compared to other algorithms at the frequency band of 170-250Hz.

• International Journal of Computer Science & Network Security
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• v.21 no.1
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• pp.152-161
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• 2021

The paper focuses on Device-to-device (D2D) Architectures evaluation frameworks. D2D communication and discovery can improve spectrum usage efficiency and optimize the tradeoffs between throughput and energy consumption. The target operation modes involve both indirect communication between two nodes via a base station or the direct communication among proximal nodes, enabling use cases that can support communications out of cellular coverage, as well as low end-end delay requirements. The paper will present the architectural evolution of D2D networks within 3GPP standardization and will highlight key network functionalities and signaling protocols. It will also identify key analytical and simulation models that can be used to assess the performance and energy efficiency of resource allocation strategies, and it will present a suitable cross-layer integrated framework.