• Tuberculosis and Respiratory Diseases
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• v.41 no.2
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• pp.103-110
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• 1994

To find out the predictors of nocturnal arterial oxygen desaturation in patients with respiratory diseases, transcutaneous oxygen saturation($StcO_2$) monitoring studies using a pulse oximeter were performed during sleep in 20 patients. $StcO_2$ was decreased more than 4% from the baseline value in 18 patients(90%) and more than 10%("Desaturator") in 8(40%). Five of the seven patients(71.4%) with awake $PaO_2$<60mmHg and three of the thirteen patients(23.1%) with awake $PaO_2{\geq}60mmHg$ were "desaturators". The awake $PaO_2/FIO_2$ and $PaO_2/PAO_2$ could distinguish "desaturator" from "nondesaturator", and $PaO_2,\;SaO_2$ or $StcO_2$ could not. These results suggest that the nocturnal oxygen desaturation depends on the severity of the underlying disease rather than the baseline $PaO_2$. Anthropomorphic and lung function factors could not separate between "desaturator" and "non-desaturator", and about a quater of patients with a wake $PaO_2{\geq}60mmHg$ developed significant desaturation. Therefore, it is necessary to monitor the nocturnal arterial oxygen saturation in patients with respiratory diseases regardless of their severity of airflow obstruction or awake $PaO_2$.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.681-684
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• 2015

Power amplifier is an essential component for transmitting signals to a remote receiver in wireless communication systems. Power amplifier is a non-linear device in general, and the nonlinear distortion becomes severer as the output power increases. The nonlinearity results in spectral regrowth, which leads to adjacent channel interference, and decreases the transmit signal quality. To linearize power amplifiers, many techniques have been developed so far. Among the techniques, digital pre-distortion is known as the most cost and performance effective technique. However, the linearization performance falls down abruptly when the power amplifier operates in its saturation region. This is because of the severe nonlinearity. To relieve this problem, this paper proposes a new adaptive predistortion technique. The proposed technique controls the adaptive algorithm based on the power amplifier input level. Specifically, for small signals, the adaptive predistortion algorithm works normally. On the contrary, for large signals, the adaptive algorithm stops until small signals occur again. By doing this, wrong coefficient update by severe nonlinearity can be avoided. Computer simulation results show that the proposed method can improve the linearization performance compared with the conventional digital predistortion algorithms.

• Journal of the Korean GEO-environmental Society
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• v.6 no.3
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• pp.55-61
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• 2005

Dynamic compaction is a ground improvement technique which is particularly effective for loose granular soils. It has also been used successfully to the cohesive soils with high void ratio, and wastes and fills. For the design of dynamic compaction method, prediction of depth of improvement is very important. The depth of improvement is influenced not only by compaction energy but also by many parameters such as grid spacing, soil property, degree of saturation and site conditions. Based on the test results, the depth of improvement were evaluated with considering compaction energy, soil type and ground water level.

• Journal of Conservation Science
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• v.28 no.1
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• pp.75-86
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• 2012

Iksan Mireuksaji Stone pagoda was built A.D. 639 when King Moo was governing Baekje, in which Sarira has been enshrined in a hole dug in the stereobate for 1,370 years. In South Korea, about 150 cases of Sarira have been found so far. In this connection, many studies have been conducted on how to manage it and on its genesis, but there have been no data on environments to which it has been exposed. In this study, accordingly, researches were made into environments to which Sarira has been exposed as well as into how much it has been damaged under the environments. Sarira in wooden pagodas was influenced greatly by water, but that in stone pagodas by saturated relative humidity. Thus, Sarira in the containers was significantly influenced by the outside temperature for 1 to 2 days, but had no any reaction to humidity. The time it took for the humidity in a Sarira container to reach its maximum, varied depending upon the humidity of the day when Sarira was enshrined. In the case of this pagoda, the humidity reached its maximum 30 days later.

• Korean Journal of Weed Science
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• v.8 no.1
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• pp.28-32
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• 1988

The effects of standing water and cultivation frequency on emergence of Echinochloa glabrescens Munro ex. Hook were determined at varied seeding methods under simulated field conditions for 4 months. In soil-incorporated seeding method total emergence for 4 months was highest in saturated condition followed by 4, 2, and 8cm standing water, whereas total emergence of seeds sown at the soil surface was highest at 2cm standing water followed by 4cm, saturated soil, and 8cm standing water. Within 2 weeks the emergence was highest at 4cm and lowest at 2cm standing water with the soil-incorporated seeding, but the seeds sown at the soil surface with 2cm standing water resulted in the highest emergence. Ratio of emergence within 2 weeks over total emergence during 4 months was lowest at 2cm standing water in the soil incorporation, indication that 2cm standing water would be the critical water level for E. glabrescens. Since most of the seedling was emerged within 2 weeks just before cultivation, the emergence pattern was little affected by cultivation at each standing water level.

• Journal of the Korean Geotechnical Society
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• v.19 no.2
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• pp.57-64
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• 2003

The liquefaction potential of saturated sands under seismic loading conditions has been carefully considered by many investigations. Typical of these investigations is the laboratory determination of cyclic strength of sands by means of cyclic triaxial tests. This study was conducted to investigate the effects of the method of sample preparation on the liquefaction characteristics of remolded samples of saturated uniform sands. Cyclic triaxial tests were performed on saturated uniform sand compacted to the same density by 3 different procedures of pluvial compaction through air, pluvial compaction through water and vibratory compaction. It was validated that the cyclic stress ratio of remolded saturated uniform sands by different compaction procedures at the same density was very different.

• Digital Contents
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• no.7 s.146
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• pp.40-49
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• 2005

경기침체에도 불구하고 국내 디지털콘텐츠 산업은 성장세를 지속해왔다. 그러나 기업간 수익편차가 심하고,IT분야의 내수시장이 포화될 것이라는 전망이 나오면서 이를 해결하기 위한 모범 답안으로 해외 진출이 제시돼왔다. 이에 <디지털콘텐츠>는 해외 주요 국가의 디지털콘텐츠 시장에 대한 분석자료를 연재한다. 연재 내용은 한국소프트웨어진흥원이 조사한‘2004년 디지털콘텐츠 산업 해외시장 보고서’를 재구성한 것으로 이번호에는 미국 e러닝 시장을 살펴봤다.

• Digital Contents
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• no.6 s.145
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• pp.54-61
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• 2005

경기침체에도 불구하고 국내 디지털콘텐츠 산업은 성장세를 지속해왔다. 하지만 기업간 수익편차가 심하고, 내수시장이 포화될 것이라는 전망이 나오면서 이를 해결하기 위한 모범답안으로 해외진출이 제시돼왔다. 이에 <디지털콘텐츠>는 해외 주요 국가의 디지털콘텐츠 시장에 대한 분석자료를 연재한다. 연재 내용은 한국소프트웨어진흥원이 조사한‘2004년 디지털콘텐츠 산업 해외시장 보고서’를 재구성한 것으로 이번호에는 미국 온라인음악 시장을 살펴봤다.

• Tuberculosis and Respiratory Diseases
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• v.47 no.2
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• pp.231-238
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• 1999

Background: Nocturnal hypoxemia occurs in patients with chronic obstructive pulmonary disease(COPD) and the detection and treatment of nocturnal hypoxemia should be part of the management of COPD patients. We performed this study to evaluate the factors influencing to sleep related arterial oxygen desaturation($SaO_2$) in patients with COPD. Methods: Resting and exercise cardiopulmonary function test, polysomnography, and $SaO_2$ during resting, exercise and sleep were measured in 12 patients with COPD. Results: The $SaO_2$ fell twice as much during sleep as during maximal exercise($13.1{\pm}9.3%$ fall in nocturnal $SaO_2$ vs. $6.4{\pm}3.3%$, p<0.05). Fall in nocturnal $SaO_2$ was well correlated with mean exercise $SaO_2$(r=-0.78, p<0.05), minimum exercise $SaO_2$(r=-0.90, p<0.01), and resting $SaO_2$(Cr=-0.82, p<0.05). Lowest sleep $SaO_2$ was well correlated with mean exercise $SaO_2$(r=0.80, p<0.05), lowest exercise $SaO_2$(r=0.90, p<0.01), and resting $SaO_2$(r=0.84, p<0.05). Conclusion: Resting and exercise $SaO_2$ was well correlated with nocturnal $SaO_2$, but exercise study add no additional information to predicting the nocturnal oxygen desaturation in patients with COPD.

• Digital Contents
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• no.8 s.147
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• pp.30-38
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• 2005

경기침체에도 불구하고 국내디지털콘텐츠 산업은 성장세를 지속해왔다 . 그러나 기업간 수익편차가 심하고 IT분야의 내수시장이 포화될 것이라는 전망이 나오면서 이를 해결하기 위한 모범 답안으로 해외 진출이 제시돼 왔다. 이에 <디지털콘텐츠>는 해외 주요국가의 디지털콘텐츠 시장에 대한 분석자료를 연재한다.연재 내용은 한국소프트웨어진흥원이 조사한‘2004년 디지털콘텐츠 산업 해외시장 보고서’를 재구성한 것으로 이번호에는 미국과 유럽의 웹정보 콘텐츠 시장에 대해 소개한다. 본 기사에서 다루는 웹정보 콘텐츠는‘정형화된 데이터베이스 형태로 축적돼 웹상에서 유통되는 정보 콘텐츠’에 한정한다.