• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.106-109
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• 2002

In order to delineate the flow system of fractured hard rock aquifer, numerical experiments are conducted and the results are analyzed with Mote Carlo simulation. The results show that the percolation threshold and the effective conductivity of a fracture network can be estimated with power law exponent (a) and fracture intensity. But the dependability of the estimated value relies on the percolation threshold, the system scale, and the characterization level.

• JSTS:Journal of Semiconductor Technology and Science
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• v.10 no.3
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• pp.240-250
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• 2010

Double Gate MOSFETs (DG MOSFETs) with doping in one or two thin layers of an otherwise intrinsic channel are simulated to obtain the transport characteristics, threshold voltage and leakage current. Two different device structures- one with doping on two layers near the top and bottom oxide layers and another with doping on a single layer at the centre- are simulated and the variation of device parameters with a change in doping concentration and doping layer thickness is studied. It is observed that an n-doped layer in the channel reduces the threshold voltage and increases the drive current, when compared with a device of undoped channel. The reduction in the threshold voltage and increase in the drain current are found to increase with the thickness and the level of doping of the layer. The leakage current is larger than that of an undoped channel, but less than that of a uniformly doped channel. For a channel with p-doped layer, the threshold voltage increases with the level of doping and the thickness of the layer, accompanied with a reduction in drain current. The devices with doped middle layers and doped gate layers show almost identical behavior, apart from the slight difference in the drive current. The doping level and the thickness of the layers can be used as a tool to adjust the threshold voltage of the device indicating the possibility of easy fabrication of ICs having FETs of different threshold voltages, and the rest of the channel, being intrinsic having high mobility, serves to maintain high drive current in comparison with a fully doped channel.

• Journal of Preventive Medicine and Public Health
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• v.24 no.1 s.33
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• pp.86-92
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• 1991

To test if exposure history to rifle fire or cannonade training during military duty can induce hearing loss, history of personal military service and histroy of gunshot exposure were asked to 228 male college students with self -administrative questionnaire. Otoscopic examination and Rinne's test were performed if any abnormal finding was detected by pure-tone audiometry. Average hearing threshold levels of 500 Hz, 1,000 Hz, 2,000 Hz, 4,000 Hz and threshold levels at 4,000 Hz were calculated for 112 students who were remained after exclusion of cases with history of ear disease, of ototoxic drug administration, and of neuropsychiatric disease, and mean of those were compared between group of students who have completed military duty (completed group) and group of those who have not (not-completed group), and between group exposed (exposed group) and group unexposed to gunshot sound (unexposed group). Mean of average hearing threshold level and mean of threshold levels at 4,000 Hz of completed group and those of exposed group were higher than those of not-completed group and unexposed group, respectively. Proportion of cases that average threshold level was greater than 40 dB or threshold levels at 4,000 Hz was greater than 50 dB were higher also in completed group and exposed group than in duty not-completed group and unexposed group, respectively Multiple linear regression analysis including age, duration of military service, degree of gunshot sound exposure as independant variables and average hearing threshold level as dependant variable, was performed in order to estimate the effect of age on hearing, and any considerable effect of age on hearing could not be found. In conclusion, hearing impairment can be induced by rifle fire or cannonade training.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.3
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• pp.581-586
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• 2017

The well-known Integral Pulse Frequency Modulation (IPFM) cardiac oscillator has been used to generate the heart beat fluctuations as a representation of the modulatory autonomic nervous activity in terms of sympathetic and parasympathetic state. The IPFM model produces heartbeats by integrating the modulated sinusoid signals and applying the threshold of unity or chaotic threshold levels. This study aims at evaluating the performance of IPFM model by analyzing the influence of the threshold level with comparatively applying preset threshold of unity and Logistic-map and Henon-map chaotic-threshold. Based on our simulated results with interpreting the spectral features of Heart Rate Variability (HRV), we can conclude that the IPFM model with preset threshold level of unity can generate the optimal heartbeat variations int the sense of clinically valid heartbeats.

• Journal of Electrical Engineering and information Science
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• v.3 no.2
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• pp.274-279
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• 1998

We investigate a Leaky Bucket(LB) scheme with a threshold in the data buffer, where leaky rate changes depending on the contents of data buffer. We use the fluid flow model for the analysis of the LB scheme with a threshold. We model the bursty input source as markov modulated fluid flow(MMFF) As performance measures we obtain loss probability and mean delay. We present some numerical results to show the effects of the level of a threshold, the rate of token generation, the size of token pool, and the size the data buffer on the performances of the LB scheme with a threshold.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.21 no.3
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• pp.162-167
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• 2011

To identify the relationship between types of job classification (typical and atypical) and the levels of recognition of noise and the hearing threshold shift, a total of 457 workers in a cosmetic company were studied utilizing a questionnaire and the audiometric hearing test. The results were analyzed by factor analysis, t-test, and general linear model, as appropriate. The results showed that atypical workers had higher level of noise recognition but had lower levels of hearing ability, noise exposure, and the knowledge on hearing loss prevention, compared with those of typical workers. The high noise level group of typical workers showed higher threshold shift levels than that of atypical workers. Significant differences were found at 4 kHz for both ears and in right ear only for hearing threshold shift after adjusting age.

• Journal of Preventive Medicine and Public Health
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• v.31 no.2 s.61
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• pp.285-292
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• 1998

To investigate the effect of smoking on the hearing threshold, 1,887 adult male workers who visited health care center during the period 1 January 1996 - 31 July 1997 were selected. Air-conduction hearing threshold level, diastolic blood pressure(DBP), total cholesterol, fasting blood sugar(FBS), hematocrit and obesity were measured. The data on age, occupation, and smoking were collected. Air-conduction hearing threshold in smoker was significantly higher than non-smoker in categories of 250, 500, 1000 and 4000 Hz(p<0.05). Mean values of PTA-low, PTA-mid, and PTA-high in smoker were also significantly higher than non-smoker(p<0.05). In multiple regression analysis, smoking is likely to play a significant role after controlling age, occupation, DBP, FBS, total cholesterol, hematocrit, and obesity(p<0.05). The hearing threshold was significantly increased with increasing age(p<0.05), the manufacturing worker may have higher hearing threshold(p<0.05). The higher hematocrit and the more obese, the higher hearing threshold(p<0.05). However, DBP, total cholesterol and FBS were not significantly related with hearing threshold level. In conclusion, smoking was significantly related with the hearing threshold level in adult men.

• The Journal of the Korea institute of electronic communication sciences
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• v.4 no.3
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• pp.190-196
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• 2009

A new time adapted threshold using the standard deviations of Wavelet coefficients after Wavelet transform by frame scale is proposed. The time adapted threshold is set up using the sum of standard deviations of Wavelet coefficient in level 3 approximation and weighted level 1 detail. Level 3 approximation coefficients represent the voiced sound with low frequency and level 1 detail coefficients represent the unvoiced sound with high frequency. After reducing noise by soft thresholding with the proposed time adapted threshold, there are still residual noises in silent interval. To reduce residual noises in silent interval, a detection algorithm of silent interval is proposed. From simulation results, it can be noticed that SNR and MSE of the proposed algorithm are improved than those of Wavelet transform and than those of Wavelet packet transform.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.10 no.2
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• pp.1-6
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• 2012

Purpose : This study is to investigate the modulatory effects to the ultraviolet induced erythema of pain processing system. Methods : Thirty six healthy volunteers were divided into none treatment group (n=6), indomethacine group (n=6), subsensory level electrical stimulation group (n=6), sensory level electrical stimulation group (n=6), motor level electrical stimulation group (n=6), noxious level electrical stimulation group (n=6). Subjects were induced erythema for three times minimal erythema dose (MED) at upper arm of dermatome C6 level. Each experimental group had mechanical pain threshold (MPT), electrical pain threshold (EPT), thermal pain threshold (TPT). Results : This study revealed that we observed that pain thresholds were significantly correlated with each other in pain processing system. The effect of electrical stimulation levels evaluates were shown to be significant differences pain control effect in electrical stimulation group (sensory, motor level electrical stimulation groups) more than indomethacine group, subsensory level and control group. Conclusion : In this study, it was found that the effect of ultraviolet induced erythema of pain control by modulatory electrical stimulation.

• Journal of the Korean Society of Physical Medicine
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• v.9 no.4
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• pp.433-438
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• 2014

PURPOSE: The purpose of our study was to compare a 975-nm, 500-mW GaAlAs low-level laser therapy versus placebo low-level laser therapy with regard to the immediate changes on the myofascial trigger point of the dominant upper trapezius muscle in subjects with rounded shoulder posture. METHODS: Thirty-two male college students with rounded shoulder posture and shoulder pain consented to participate in the experiment. The subjects were randomly assigned to a 2-minute procedure with either an active GaAlAs low-level laser or a placebo GaAlAs low-level laser. The pressure-pain threshold and visual analog scale on tenderness at 3 kg were measured with an algometer before and after the laser treatments. RESULTS: The active GaAlAs low-level laser group showed significant changes in pressure-pain threshold and visual analog scale on tenderness at 3 kg (p<0.05). The placebo GaAlAs low-level laser group showed no significant changes in either pressure-pain threshold or visual analog scale on tenderness at 3 kg (p>0.05). CONCLUSION: An immediate effect was observed in pressure-pain threshold and visual analog scale on tenderness at 3 kg following a 2-minute application ($857.14J/cm^2$) of a 975-nm, 500-mW GaAlAs low-level laser to the myofascial trigger point of the dominant upper trapezius muscle in patients with rounded shoulder posture.