• Korean Journal of Audiology
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• v.25 no.2
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• pp.65-71
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• 2021

Background and Objectives: In masking level difference (MLD), the masked detection threshold for a signal is determined as a function of the relative interaural differences between the signal and the masker. Study 1 analyzed the results of school-aged children with good school performance in the MLD test, and study 2 compared their results with those of a group of children with poor academic performance. Subjects and Methods: Study 1 was conducted with 47 school-aged children with good academic performance (GI) and study 2 was carried out with 32 school-aged children with poor academic performance (GII). The inclusion criteria adopted for both studies were hearing thresholds within normal limits in basic audiological evaluation. Study 1 also considered normal performance in the central auditory processing test battery and absence of auditory complaints and/or of attention, language or speech issues. The MLD test was administered with a pure pulsatile tone of 500 Hz, in a binaural mode and intensity of 50 dBSL, using a CD player and audiometer. Results: In study 1, no significant correlation was observed, considering the influence of the variables age and sex in relation to the results obtained in homophase (SoNo), antiphase (SπNo) and MLD threshold conditions. The final mean MLD threshold was 13.66 dB. In study 2, the variables did not influence the test performance either. There was a significant difference between test results in SπNo conditions of the two groups, while no differences were found both in SoNo conditions and the final result of MLD. Conclusions: In study 1, the cut-off criterion of school-aged children in the MLD test was 9.3 dB. The variables (sex and age) did not interfere with the MLD results. In study 2, school performance did not differ in the MLD results. GII group showed inferior results than GI group, only in SπNo condition.

• Korean Journal of Acupuncture
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• v.40 no.3
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• pp.99-108
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• 2023

Objectives : The aim of this study was to assess the quantitative characteristics of pressure pain threshold (PPT) and pressure depth (PD) at the abdominal conception vessel (CV) acupoints according to subjective digestive status and digestive discomfort levels, accomplished by comparing a large group of healthy men and women, using the modified digital algometer. Methods : A total of 1,504 healthy adults aged 19 years or older participated in this study. A questionnaire was administered to evaluate participants' digestive status and discomfort. PPT (kgf/cm²/s) and PD (mm) measurements were obtained at CV14, CV12, and CV4 acupoints using a modified digital algometer. General characteristics were analyzed using the chi-square test, and differences in PPT and PD were assessed using two-sample t-tests and ANCOVA. Results : Significant difference in PPT was found based on digestive status at CV14 and CV12 for both sexes, and in PD at CV14 for women. Women exhibited significant difference in PPT based on digestive discomfort at CV14, CV12, and CV4, while men showed significant difference at CV14 and CV12. Significant difference in PD was observed at CV14 and CV4 among women. Even after adjusting for age and body mass index, significant difference persisted in PPT based on digestive discomfort at CV14 and CV12 for both sexes. PD exhibited significant differences at CV14, CV12, and CV4 among women. Conclusions : Using the modified digital algometer, this study showed the significant difference of pressure pain threshold at the CV14 and CV12 acupoints for subjective digestive discomfort levels in healthy men and women.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.4
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• pp.195-203
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• 2015

In this study, the carrier acceleration-ramp-step test was applied to GPS carrier phase measurements, and the results were compared and analyzed. In the carrier acceleration-ramp-step test, the acceleration, ramp, and measurements are estimated using 10 consecutive carrier phase measurements for satellites observed at the same time based on the least square method. As for the characteristic of this test, if failure occurs in the measurement, the value jumps significantly compared to the previous result; but it judges that failure has occurred in all the satellites although failure has occurred in one satellite. Therefore, in this study, a method that eliminates a satellite with failure was suggested, and thresholds of the carrier acceleration, ramp, and step were suggested. The evaluation of the failure detection performance of carrier phase measurement using the suggested thresholds showed that failure could be detected when the carrier phase measurement changed abruptly by more than about 0.1 cycles.

• Korean Journal of Veterinary Research
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• v.41 no.3
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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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.4
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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.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.12 no.1
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• pp.115-122
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• 1992

Stochastic rainfall-runoff process model which is mainly used in real-time streamflow forecasting is Transfer Function(TF) model that has a simple structure and can be easy to formulate state-space model. However, in order to forecast the streamflow accurately in real-time using the TF model, it is not only necessary to determine accurate structure of the model but also required to reduce forecasting error in early stage. In this study, after introducing 5-day Antecedent Precipitation Index (API5), which represents the initial soil moisture condition of the watershed, by using the threshold concept, the TF models in each API5 are identified by Box-Jenkins method and the results are compared with each other.

• Journal of Biomedical Engineering Research
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• v.14 no.1
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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.

• Journal of the Society of Naval Architects of Korea
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• v.43 no.4 s.148
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• pp.494-503
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• 2006

Inherent damage zone model is presented to explain the fatigue properties near the fatigue limit and the crack growth threshold consistently Inherent damage zone model assumes that the stress at a point which is located at a small distance, $r_0$, an inherent length of the material that represents the size of effective damage zone, from the crack initiation position governs the fatigue characteristics regardless of the geometric configuration of the specimen; smooth specimen, notched specimen or cracked specimens with short and long crack length. A special feature of the paper is using the exact stress distributions of notched and cracked specimens at the strength evaluations. Analytical elastic solutions by Neuber and Westergaard are employed for this purpose Relationship between fatigue limit of smooth specimen and threshold stress of cracked specimen, occurrence condition of non-propagating crack at the root of elliptic notch and circular hole and relationship between stress concentration factor and fatigue notch factor are discussed quantitatively based on the proposed model.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1203-1207
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• 2008

For a large sized, ultra definition (UD) and high refresh rate for motion blur free AMLCD TVs, amorphous IGZO thin film transistor (TFT) are applied and investigated in terms of threshold voltage ($V_{th}$) shift influenced by active layer thickness uniformity, source drain etching technology, heat treatment and passivation condition. Optimizing above parameters, we fabricated the world's largest 15 inch XGA AMLCD successfully.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.12-12
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• 2010

Time dependence of the shift of the threshold voltage of amorphous hafnium-indium-zinc oxide (a-HIZO) has been reported under on-current stress condition. a-HIZO thin films were deposited on $SiO_2$/Si (100) by rf magnetron sputtering. XPS measurement indicates that the Hf metal cations in a-HIZO system after annealing process reduce oxygen vacancies by binding oxygen. It was found that the Hf metal cation can be effectively incorporated in the IZO thin films as a suppressor against both the oxygen deficiencies and the carrier generation in the ZnO-based system.