• 한국음향학회지
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• 제23권1호
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• pp.82-89
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• 2004

고음질 합성을 하면서도 다양한 음색을 갖도록 하기 위해서는 파형부호화를 이용한 합성법에 적용할 수 있는 피치 변경법이 필요하다. 따라서 본 논문에서는 스펙트럼 왜곡률을 최소화하는 영교차 단위의 시간축 조절에 의한 피치 변경법과 피치 동기분석이 용이하고 다른 영역으로의 변환과정이 불필요한 피치시점 검출법을 제안함으로써 고음질을 유지하면서 시간영역에서만 처리됨으로써 계산량을 줄이고 스펙트럼 왜곡률을 최소화하고 위상을 그대로 보존할 수 있는 시간영역에서의 피치 변경법을 제안하였다. 결과적으로 전체 피치 변경율에 대해서는 기존의 방법에 비해서 제안한 방법의 스펙트럼 왜곡률이 0.73%개선되었고 피치 압축시에는 제안한 방법의 스펙트럼 왜곡율이 2.18%개선되었다.

• 대한수의학회지
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• 제41권3호
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• pp.311-317
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• 2001

In this work we have investigated the physiological effects of $MgCl_2$ in isolated atrium, papillary muscle, perfused heart and anesthesized guinea pig, The addition or infusion of $MgCl_2$ (0~20 mM or mg/kg) to perfused hearts and to anesthesized guinea pigs induced a marked and dose-dependent negative chronotropic effect. The sinoatrial node automaticity could also be reduced by $MgCl_2$. The addition of $MgCl_2$to isolated atria and to papillary muscles induced a marked and dose-dependent negative inotropic effect. The threshold voltage could be increased by $MgCl_2$in papillary muscle. Increasing $MgCl_2$ shortened the action potential duration (APD) in dose-dependent manner at 30% ($APD_{30}$) and 90% repolarization ($APD_{90}$) measured with conventional microelectrode technique in papillary muscle. In anesthesized guinea pig, the magnesium infusion resulted in a dose-dependent drop in blood pressure. These results suggested that magnesium is closely associated with cardiac physiological condition and exerts antiarrhythmic activities.

• 한국전기전자재료학회논문지
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• 제27권4호
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• pp.199-202
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• 2014

The effect of neutron irradiation on the properties of SiC Schottky Diode has been investigated. SiC Schottky diodes were irradiated under neutron fluences and compared to the reference samples to study the radiation-induced changes in device properties. The condition of neutron irradiation was $3.1{\times}10^{10}$ $n/cm^2$. The current density after irradiation decreased from 12.7 to 0.75 $A/cm^2$. Also, a slight positive shift (${\Delta}V_{th}$= 0.15 V) in threshold voltage from 0.53 to 0.68 V and a positive change (${\Delta}{\Phi}_B$= 0.16 eV) of barrier height from 0.89 to 1.05 eV have been observed by the neutron irradiation, which is attributed to charge damage in the interface between the metal and the SiC layer.

• Toxicological Research
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• 제17권
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• pp.41-45
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• 2001

The methods used for risk assessment from exposure to chemicals are well established. in most cases where toxicity other than carcinogenesis is being considered, the standard method relies on establishing the No Observed Adverse Effect Level (NOAEL) in the most sensitive animal toxicity study and using an appropriate safety factor (SF) to determine the exposure which would be associated with an acceptable risk. For carcinogens a different approach is used because it has been argued there is no threshold of effect. Thus mathematical equations are used to extrapolate from the high doses used in ani-mal experiments. These methods have been strongly criticised in recent years on several grounds. The most cogent criticisms are a) the equations are not based on a thorough understanding of the mechanisms of carcinogenesis and b) the outcome of a risk assessment based on such models varies more as a consequence of changes to the assumptions and equation used than it does from the data derived from carcinogenicity experiments. Other criticisms include the absence of any measure of the variance on the risk assessment and the selection of default values that are very conservative. Recent advances in the application of risk assessment emphasise that measures of both the exposure and the hazard should be considered as a distribution of values. The outcome of such a risk assessment provides an estimate of the distribution of the risks.

• 대한의용생체공학회:의공학회지
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• 제14권1호
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• pp.63-72
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• 1993

In this paper, the effect of background grey levels on the visual perception of target image displayed on CRT monitor has been investigated. The purpose of this study is to investigate the efficacy of CRT monitor as a display medium of image Information especially in medical imaging field. Tllree sets of experiments have been performed in this study : the first was to measure the luminance response of CRT monitor and to find the best fitting equation, and the second was the psychophysical experiment measuring the threshold grey level differences between the target image and the background required for visual discrimination (or various background grey levels, and the third was to develop a visual model that is predictable of the threshold grey level difference measured in the psychophysical experiment. The result of psycophysical experiment shows that the visual perception performance is significantly degraded in the range of grey levels lower than 50, which is turned out due to she low luminance change of CRT monitor in this range while human eye has been adapted lo relatively bright ambient illumination. And it Is also shown in the simulation study using the developed visual model that the dominant factor degrading the visual performance is the reflected light from the monitor surface by ambient light in general illumination condition.

• The Korean Journal of Physiology and Pharmacology
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• 제7권6호
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• pp.369-373
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• 2003

This study was performed to test whether endomorphin-1 has analgesic effect, when locally administrated into inflamed peripheral tissue. Carrageenan suspension (0.5%) was injected intraplantarly into the right paw of Sprague-Dawley male rats, and the rats were subjected to a series of mechanical stimuli with von Frei filaments before and after the injection. Carrageenan-injected rats showed typical inflammatory hyperalgesic signs and decrease of withdrawal threshold, peaked at 3 to 6 hours after the injection and lasted more than 3 days. Endomorphin-1 was intraplantarly injected with carrageenan, simultaneously or 3∼4 hours after carrageenan. Simultaneous injection of endomorphin-1 with carrageenan significantly reduced hyperalgesia and thd analgesic effect was prolonged up to 8 hours. The delivery of endomorphin-1 ($50{\mu}g$) into the inflamed area after 3 to 4 hours of carrageenan injection significantly increased the threshold of hyperalgesic mechanical withdrawal response, but only partially. Intrathecal treatment of endomorphin-1 completely reversed carrageenan-induced hyperalgesia. This report is the first to show that peripherally delivered endomorphin-1 relieved inflammatory hyperalgesia. But a control through peripheral ${\mu}-opioid$ receptors appears to be not sufficient for complete pain treatment.

• 한국통신학회논문지
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• 제35권5C호
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• pp.432-438
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• 2010

본 논문에서는 고차 변조 방식의 심볼 사상(mapping)이 LDPC (low-density parity-check) 부호를 사용하는 터보 등화기(turbo equalizer)의 수렴 특성에 미치는 영향에 대해서 살펴본다. 심볼 사상에 따른 선형 MMSE 등화기의 유효(effective) SNR과 LDPC 복호기의 수렴 특성을 통해 LDPC 부호를 사용하는 터보 등화기에 BR (bit-reliability) 사상이 성능 관점에서 유리하다는 것을 보여준다. 그리고 밀도 진화 분석(density evolution)을 통한 잡음 임계치(noise threshold)와 전산 실험 결과를 통해 터보 등화기의 성능에 심볼 사상이 미치는 영향을 검증한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.24-25
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• 2008

The effect of heat treatment in $HfO_2$ as charge trap with $SiO_2/Si_3N_4/SiO_2$ as tunnel oxide layer in capacitors has been investigated. Rapid thermal annealing (RTA) were carried out at the temperature range of 600 - $900^{\circ}C$. It is found that all devices carried out heat treatment have large threshold voltage shift Especially, device performed heat treatment at $900^{\circ}C$ has been confirmed the largest memory window. Also, Threshold voltage shift of device used conventional $SiO_2$ as tunnel oxide layer was smaller than that with $SiO_2/Si_3N_4/SiO_2$.

• 대한정형도수물리치료학회지
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• 제22권1호
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• pp.59-64
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• 2016

Background: This study was to investigate the effect of cervical HVLA technique and mulligan MWM technique on patients with lateral epicondylitis. Methods: 36 participants were randomly allocated to the two groups; group I involved high velocity low amplitude (HVLA) cervical mobilization technique, mulligan mobilizations with movement (MWM) technique (n=18). group II mulligan MWM (n=18). Patient attended for three times a week for six weeks. Results: The change of visual analogue scale (VAS) was statistically and significantly decreased in both of the group I and the group II. The change of patients rated tennis elbow evaluation (PRTEE) was statistically and significantly decreased in both of the group I and the group II. The change of pressure pain threshold (PPT) was statistically and significantly increased in both of the group I and the group II. Nevertheless, There is no statistical differences between group I and group II. Conclusion: After experiment, pressure pain threshold and visual analogue scale, patients rated tennis elbow evaluation were improved in both group. But Cervical HVLA group does not showed the change better than mulligan MWM group.

• 한국기계가공학회지
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• 제6권1호
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• pp.62-70
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• 2007

The development of new materials that are light-weight, yet high in strength has become vital to the machinery, aircraft and auto industries. However, there are a lot of problems with developing such materials that require expensive tools, and a great deal of time and effort. Therefore, the improvement of fatigue strength and fatigue life are mainly focused on by adopting residual stress. The fatigue crack growth rate of the Shot-peened material was lower than that of the Un-peened material. And in stage I, threshold stress intensity factor of the shot-peen processed material is high in critical parts unlike the Un-peened material. Also, fatigue crack growth exponent and number of cycle of the Shot-peened material was higher than that of the Un-peened material. That is concluded from effect of da/dN. And Fatigue life shows more improvement in the Shot-peened material than in the Un-peened material. And compressive residual stress of surface on the Shot-peen processed operate resistance force of fatigue crack propagation.