• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.15 no.10
• /
• pp.797-810
• /
• 1990

The error rate equations of digitally modulated signals transmitted through the Gaussian noise and tone multiple interference channel have been derived. Using the derived equations of error probabilities in the environments of Gaussian noise tone interferer and Gaussian noise multiple interferer, the error rate performances of various digitally modulated signals have been evaluated, and compared in graphs as a function of average carrier to tone interferer power ratio(CIR), average carrier to multiple interferer power ratio(CIT) and the average carrer-to-Gaussian noise powr ratio(CIR). In this paper, the modulation schemes such as amplitude shift keying (ASK), phase shift keying(PSK), frequency shift keying(FSK), minimum shift keying(MSK), quadrature amplitud modulation(QAM) and amplitude phase shift keying(APK) have been selected for the study of performance comparison. The results of comparison show us that, in low bits/sec/Hz, PSK is superior to the other schemes, but in high bits/sec/Hz, mixed multi ary type is better than single multi ary type. And in strong noise evironment, the multiple interferer has much influence than tone interferer, however, in low noise environment. the mojor error factor is tone interferer. But tone interference effect nearly disappears over specified CIR level about 20[dB]. And the modulation schemes using amplitude are heavily influenced by multiple interference.

• Annals of Clinical Neurophysiology
• /
• v.6 no.2
• /
• pp.75-79
• /
• 2004

Backgrounds: Electrodiagnostic tests have been developed to estimate the degree of facial nerve injury during the acute phase. Side-to-side amplitude comparison with the affected side expressed as a percentage of the nonaffected side has been one of the most valuable electrophysiologic methods of assessing facial nerve functioning. This study was designed to know whether there is any difference in the side-to-side comparison of amplitudes and terminal latencies of the compound muscle action potentials (CMAP) of the facial muscles in the patients with Bell's palsy. Methods: Electroneurographic recordings with surface electrodes on the frontalis, orbicularis oculi, nasalis, and orbicularis oris muscles were made within 2 weeks post-onset (mean, day 7) in 39 patients. Results: Of the 39 Bell's palsy patients, 38 patients (97.4%) recovered satisfactorily within 6 months. The amplitude of CMAP in all patients was not reduced to 10% or less of that of the contralateral healthy muscle. The correlation of amplitude change between four facial muscles was relatively strong, but the correlation of latency change was weak. When the electroneurographic values were compared in the four muscle groups, the general linear models procedure did not show any significant difference for CMAP amplitude and latency changes (p=0.62-0.63). Conclusions: This study did not show any significant clinical advantage of electroneurographic recordings in more than one facial muscle at the early stage of Bell's palsy.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.35 no.2
• /
• pp.30-36
• /
• 2012

This study is aimed to show that an asymmetric load in the frontal plane leads to an increase in low back loading and fatigue in comparison with a symmetric load when workers lift an external weight by investigating previous studies and verifying the phenomenon with an experiment. Ten male subjects are required to lift and hold an given external load at 70cm height during 50sec, then the EMG amplitude and median frequency on bilateral low back muscle groups (Longissimus, Iliocostalis, and Multifidus) are recorded and analyzed. Independent variables are two-level load weight (13kg, 20kg) and three-level LCG (Center, 6.5cm to the right, and 13cm to the right), and dependent variables are EMG amplitude average, difference, and Fatigue Index (FI). Results show that load weight increases significantly amplitude average and FI, but LCG does significantly amplitude difference and FI significantly (P-value < 0.05). Also the correlation coefficient between amplitude difference and FI is over 0.99. These implies that trunk loading should be explained by not EMG amplitude but muscle fatigue aspect since the association between an external load and amplitude is linear, but the relationship between an external load and median frequency as muscle fatigue index is almost exponential.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 1999.06a
• /
• pp.303-309
• /
• 1999

The fretting wear behaviour of Zircaloy-4 tube used as the fuel rod cladding in PWR nuclear power plants has been investigated at the different test environment, in light water and in air as a function of slip amplitude, normal load, test duration and frequency. Zircaloy-4 tubes were used for both of oscillating and stationary specimens. A fretting wear tester was designed to be suitable for this fretting test. The wear volume and specific wear rate of Zircaloy-4 tube in water were greater than those in air under various slip amplitude. It was found that delaminate debris and surface cracks were observed at low slip amplitude and high load in water Experimental results showed that the light water accelerated the wear of Zircaloy-4 tube at low slip amplitude in fretting.

• Tribology and Lubricants
• /
• v.15 no.1
• /
• pp.83-89
• /
• 1999

The fretting wear behaviour of Zircaloy-4 tube used as the fuel rod cladding in PWR nuclear power plants has been investigated at the different test environment, in light water and in air as a function of slip amplitude, normal load, test duration and frequency. Zircaloy-4 tubes were used for both of oscillating and stationary specimens. A fretting wear tester was designed to be suitable for this fretting test. The wear volume and specific wear rate of Zircaloy-4 tube in water was greater than those in air under various slip amplitude. Delaminates and surface cracks were observed at low slip amplitude and high load of fretting test in water, but the traces of adhesion and plowing were observed at and above 200 Um. The water accelerates the wear of Zircaloy-4 tube at lower slip amplitude in fretting.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.61 no.8
• /
• pp.1193-1198
• /
• 2012

An instantaneous amplitude (IA) estimator using the symmetric higher order differential energy operator is proposed. The amplitude estimator and the instantaneous frequency (IF) estimator based on the symmetric higher order differential energy operator coincide with the analyzed signal in time, and they show better estimation results than the IA and IF based on the higher order differential energy operator. Various IF and IA estimators are applied to AM-FM signals for the performance comparison. Among the IF and IA estimators, the IF and IA estimators based on the symmetric higher order energy operator show the best estimation accuracy. Then, the IA and IF estimators are applied to the distorted power line signal to show their usefulness as power disturbance detectors.

• Journal of The Korean Astronomical Society
• /
• v.56 no.1
• /
• pp.125-135
• /
• 2023

Here, we investigated the observed sunspot areas with respect to latitudes using the Hilbert transform technique. Conventional study of the cyclic patterns of sunspots is based on the Lomb-Scargle periodogram, which only obtains the amplitude information. In comparison, our approach characterizes the amplitude as well as the phase of solar activity. We demonstrated the solar North-South asymmetry in the instantaneous amplitude by analyzing daily sunspot data set spanning from the solar cycles 11 to 24. Our findings confirm that the northern hemisphere is dominant in the solar cycles 14, 15, 16, 18, and 20. Unlike the amplitude, the North-South asymmetry in the period of solar activity could not be established. We have also found that the standard deviation as a measure of fluctuation in the phase derivative is minimum in the latitude band 10° < l < 20°, and the fluctuations obtained for latitudes above 30° are considerable.

• International Neurourology Journal
• /
• v.22 no.4
• /
• pp.268-274
• /
• 2018

Purpose: To describe a technique for urodynamic diagnosis of detrusor sphincter dyssynergia (DSD) using urethral pressure measurements and examine potential associations between urethral pressure and bladder physiology among patients with DSD. Methods: Multiple sclerosis (MS) and spinal cord injured (SCI) patients with known DSD diagnosed on videourodynamics (via electromyography or voiding cystourethrography) were retrospectively identified. Data from SCI and MS patients with detrusor overactivity (DO) without DSD were abstracted as control group. Urodynamics tracings were reviewed and urethral pressure DSD was defined based on comparison of DSD and control groups. Results: Seventy-two patients with DSD were identified. Sixty-two (86%) had >20 cm $H_2O$ urethral pressure amplitude during detrusor contraction. By comparison, 5 of 23 (22%) of control group had amplitude of >20 cm $H_2O$ during episode of DO. Mean duration of urethral pressure DSD episode was 66 seconds (range, 10-500 seconds) and mean urethral pressure amplitude was 73 cm $H_2O$ (range, 1-256 cm $H_2O$). Longer (>30 seconds) DSD episodes were significantly associated with male sex (81% vs. 50%, P=0.013) and higher bladder capacity (389 mL vs. 219 mL, P=0.0004). Urethral pressure amplitude measurements during DSD were not associated with significant urodynamic variables or neurologic pathology. Conclusions: Urethral pressure amplitude of >20 cm $H_2O$ during detrusor contraction occurred in 86% of patients with known DSD. Longer DSD episodes were associated with larger bladder capacity. Further studies exploring the relationship between urethral pressure measurements and bladder physiology could phenotype DSD as a measurable variable rather than a categorical observation.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.12 no.2
• /
• pp.153-158
• /
• 2012

This paper deals with the performance comparison of adaptive equalization algorithm, CMA and MMA, that is used for the minimization of the distortion and noise effect in the communication channel at receiver.. We confirmed the application possibilities of the point to point or point to multipoint digital transmission technologies by analyzing the performance of MMA which is changing the error function of CMA that is the possible algorithm of fast equalization by relatively simple arithmatic computation compared to the other method. In CMA algorithm, we need the PLL for the amplitude compensation only and not possible to phase compensation inherently. But in MMA algorithm, we confired that the amplitude and phase of received signal can be compensated by computer simulation. For the comparison of algorithm, we used the essential performance index, convergence characteristics and residual isi. The result of performance comparison of algorithms, the MMA has good in convergence characteristic and the CMA has good in residual isi that is used for the amplitude compensation.

• The KIPS Transactions:PartB
• /
• v.14B no.1 s.111
• /
• pp.13-22
• /
• 2007

In this paper, we propose an audience counting method in an auditorium based on pattern comparison. The previous counting methods based on object detection can't exactly count the audience in real time because auditorium has coarse illumination condition and so many audiences. Therefore, in this paper, we count the audience in an auditorium with fixed seats by the method which the pattern from each reference seat is compared to the pattern from each input seat. Especially, to overcome limitations based on either illumination or noise, two pattern comparison methods are efficiently employed and combined. One is based on the amplitude projection, and the other is based on Walsh-Hadamard Kernel. Walsh-Hadamard Kernel has the characteristic which complements amplitude projection. Therefore, we ran achieve the accurate counting in the presence of coarse illumination and noise. The experimental results show that our method performs well on sequences of images acquired in an auditorium. We also verify a realistic possibility for other applications applying our method to the parking positioning system.