• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.16 no.2 s.93
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• pp.189-193
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• 2005

In this paper, we propose a direct conversion double-balanced down-converter fer MB-OFDM W system, which is implemented using $0.18\;{\mu}m$ CMOS technology and its measurement results are shown. The proposed down-converter adopts a resistive current-source instead of general transconductance stage using MOS transistor to achieve wideband characteristics over RF input frequency band $3\~5\;GHz$ with good gain flatness. The measured conversion gain is more than +3 dB, and gain flatness is less than 3 dB for three UWB channels. The dc consumption of this work is only 0.89 mA from 1.8 V power supply, leading to the low-power W application.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.10a
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• pp.169-174
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• 2012

Reduction unit is one of the most important components for railway vehicle because torque of motor must be transmitted to wheels of vehicle by reduction unit. However, According to advanced studies, it has been often broke down due to the damage, fatigue and wear of gear. To solve this problem, defect diagnosis methods of gear have been mainly using the vibration diagnosis technology through vibration waveform and frequency analysis. However, We should know vibration characteristics of normal state reduction unit prior to defect diagnosis. So in this paper, We had analyzed vibration characteristics of reduction unit in order to utilize monitoring system development. Comparison of targets is the vibration characteristics of normal state reduction unit about Electric Multiple Unit(EMU) and the High-speed trains(KTX, KTX II).

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.20-25
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• 2001

In recent years, the concern about a user center design in increasing, and it's needed to task a user's visual cognitive characteristics for information presentation. Then this study aims to grasp user's cognitive characteristics about the information presentation by analyzing the fixation points. In the experiment, actually subject operated a copy machine. Recorded the fixation point movement of the operation panel by the eye mark recorder. Analysis examined the screen interface of the operation panel from the field of a fixation point trace. The top down type fixation oder by experience or the context became clear as a result. Furthermore, the difference of the fixation order by skill level was also examined. In this study, it was assumed that to grasp the visual cognitive characteristics becomes the key of efficient information.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1391-1394
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• 2007

In this work, the discharge characteristics and temporal distribution of surface charges on the Sidoped MgO have been investigated and elucidated with the results of photon-induced surface current. Even though the Si doped MgO shows lower static voltage margin, higher luminous efficacy, and shorter statistical delay time, its discharge characteristics become deteriorated as the timing of scanning is delayed from the ramp type reset pulse down. Overall features of Si-doped MgO in discharge characteristics are well correlated with surface current characteristics.

• The Journal of the Acoustical Society of Korea
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• v.6 no.2
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• pp.15-18
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• 1987

Multiplication free adaptive digital filtering algorithms are discussed. The proposed. The proposed algorithm uses delta modulation digital filter and the relevant filter weights are updated using the SIGN algorithms to realize an adaptive digital filter without multiplication operations. It is shown that the resulting algorithm can be implemented using simple up/down counting operations. The convergence characteristics of the proposed adaptive digital filtering algorithm and .others are investigated for a system identification problem.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.1000-1003
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• 2014

The primary purpose of this study is to observe the dynamic behavior within a vehicle on chassis dynamometer throughout cleat impact testing with two different constraining setups (Tie-down strap and one point fixation). Throughout this empirical experiment, no outstanding dynamic behavior characteristics are observed between two setups and thus, the performance of the one point fixation device is validated. Neither the interior noise nor acceleration at driver seat rail and knuckle is heavily influenced by two different constraining methods. However, one point fixation is far more advantageous considering its shorter set up time and its capability of measuring traction force with its built in force sensor.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.676-679
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• 2007

This paper describes an experiment facility to measure the circulation characteristics of a water/steam receiver at various heat fluxes. The natural circulation type receiver was considered in this study. The experiment facility was designed to satisfy circulation balance with an appropriate scale down. As a result, riser tube inner diameter was 7.4 mm and water circulation was 0.319 kg/s. Downcomer tube inner diameter by circulation balance was 9.52 mm and the quality was from 0 to 0.23.

• Journal of Trauma and Injury
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• v.21 no.1
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• pp.53-58
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• 2008

Purpose: Skiing and snowboarding are becoming increasingly popular. Accordingly, the incidences of injuries among skiers and snowboarders are also increasing. The purpose of this study was to investigate the injury patterns of and the contributing factors to head injuries of skiers and snowboarders and to evaluate the differences in characteristics between skiing and snowboarding head injuries. Methods: One-hundred patients who visited the emergency department of Wonju Christian Hospital between January 2005 and March 2007 due to head injuries from skiing and snowboarding were enrolled. The mechanisms and the histories of the injuries were investigated by surveying the patients, and the degrees of head injuries were estimated by using brain CT and the Glasgow Coma Scale. The degrees and the characteristics of brain injuries were also analyzed and compared between skiers and snowboarders. Results: Out of 100 patients, 39 were injured by skiing, and 61 were injured by snowboarding. The mean age of the skiers was $26.7{\pm}10.0$, and that of the snowboarders was $26.7{\pm}6.2$. The percentage of male skiers was 43.6%, and that of snowboarders was 63.9%. The most frequent initial chief complaints of head-injured skiers and snowboarders were headache and mental change. The most common mechanism of injuries was a slip down. The mean Abbreviated Injury Scale Score (AIS score) of the skier group was $4.5{\pm}2.1$ and that of the snowboarder group was $5.9{\pm}5.0$ (p=0.222). The percentage of helmet users was 7.1% among skiers and 20.8% among snowboarders (p=0.346). Head injuries were composed of cerebral concussion (92.0%) and intracranial hemorrhage (8.0%). Intracranial hemorrhage was most frequently caused by falling down (62.5%). Conclusion: The most common type of head injury to skiers and snowboarders was cerebral concussion, and severe damage was usually caused by jumping and falling down. No differences in the characteristics of the head injuries existed between skiing and snowboarding injuries.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.63-66
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• 1992

Using an aromatic system, we made a ultra thin insulator through LB-method. We measured and wrote down afternating currant characteristics of ultraviolet rays extincting-spectrum and I.R extincting-spectrum. We surveyed the thickness of a film through X-ray diffracting method and certified about $4{\AA}$ by the layer. Measuring the characteristics of direct current voltage and electric current with this sample, we produced its conductivity and discovered that this sample had a god insulating performance. Addition to this, we measured the characteristics of voltage and electric current, and the temperature dependency of conductivity in a high voltage system and with these results tried to interpret a mechanism of conduction.

• The Korean Journal of Quaternary Research
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• v.21 no.2
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• pp.77-79
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• 2007

The source regions of Asian Dusts (Yellow Sands) in the western part of China are investigated, and the soil samples are collected samples for approximately 15 days during the spring of 2005. Particle sizes of sediments are analyzed and compared with each other. These grain-size analyses from the source areas can be compared Particle sizes between loess deposits and desert sands in western part of China and desert areas show distinctive differences. Loess deposits are predominantly composed of fine sands and silts. The distinction between the final characteristics of Asian Dust particles arrived in Korea and characteristics during transportation can be recognized comparison with the Asian Dust particles collected where the dust particles settled down. The characteristics of Asian Dust particle sizes can provide the basic information regarding the transportation history from the source region.