• Earthquakes and Structures
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• v.7 no.1
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• pp.83-99
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• 2014

This study is devoted to estimate higher-mode effects for multi-story structures with considering soil-structure interaction subjected to decomposed parts of near-fault ground motions. The soil beneath the super-structure is simulated based on the Cone model concept. Two-dimensional structural models of 5, 15, and 25-story shear buildings are idealized by using nonlinear stick models. The ratio of base shears for the soil-MDOF structure system to those obtained from the equivalent soil-SDOF structure system is selected as an estimator to quantify the higher-mode effects. The results demonstrate that the trend of higher-mode effects is regular for pulse component and has a descending variation with respect to the pulse period, whereas an erratic pattern is obtained for high-frequency component. Moreover, the effect of pulse component on higher modes is more significant than high-frequency part for very short-period pulses and as the pulse period increases this phenomenon becomes vice-versa. SSI mechanism increases the higher-mode effects for both pulse and high-frequency components and slenderizing the super-structure amplifies such effects. Furthermore, for low story ductility ranges, increasing nonlinearity level leads to intensify the higher-mode effects; however, for high story ductility, such effects mitigates.

• Korean Journal of Acupuncture
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• v.26 no.2
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• pp.61-74
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• 2009

Objectives: The warm needling technique is a method which combines the effects of acupuncture with those of moxibustion. The purpose of this study was to find the stimulus effects of a high frequency warm needling device when stimulating acupoint $LI_4$ on the carrageenan-induced arthritis. Methods: This study was to observe the effects to edema reaction, WBF(weight bearing force), NO concentration, nNOS expression after the electro high frequency stimulus of high frequency warm needling device on LI4 with insulated acupuncture needle. Results: The effect of the high frequency warm needling device is to rise up the temperature in proportion to the current intensity. After stimulating on the acupoint $LI_4$ of the carrageenan-induced arthritis in rats with the high frequency warm needling device, it significantly reduced edema in the rat's foot. In addition, WBF, NO concentration of spinal cord (nmol/mg), and nNOS relative expression were reduced. Conclusions: The above results support the idea that stimulus by the high frequency warm needling device on $LI_4$ produces a potent analgesic effect in the arthritis pain model of the rat. Moreover, stimulus by the high frequency warm needling device modulates endogenous NO through the suppression of nNOS protein expression.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.4
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• pp.67-74
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• 2018

PURPOSE: This study was conducted to investigate the effects of vibration frequency and amplitude on scapular winging during the knee push-up plus exercise. METHODS: A total of 26 female subjects with scapular winging were evaluated while performing the knee push-up plus exercise with no vibration, low-frequency/low-amplitude (5 Hz/3 mm) vibration, low-frequency/high-amplitude (5 Hz/9 mm) vibration, high-frequency/low-amplitude (15 Hz/3 mm) vibration, and high-frequency/high-amplitude (15 Hz/9 mm) vibration. The surface EMG of the serratus anterior (SA) muscle was compared between the vibration frequency and amplitude. The EMG amplitude was normalized using the maximal voluntary isometric contraction (MVIC). The statistical significance of the results was evaluated using one-way ANOVA. RESULTS: The SA muscle EMG values increased at low-frequency/low-amplitude vibration and at low-frequency/high-amplitude vibration compared to no vibration. Furthermore, the same values increased at high-frequency/low-amplitude vibration and high-frequency/high-amplitude vibration compared to no vibration. In general, a higher vibration frequency and amplitude was associated with higher EMG values of the SA muscle, with particularly greater increases observed during high-frequency/high-amplitude vibration. There was also a significant difference between each condition with a high-frequency/high-amplitude vibration (p<.05). CONCLUSION: This study suggests that there were remarkable clinical effect of the knee push-up plus exercise with vibration, which enhanced the SA muscle activation in persons with scapular winging. Furthermore, applying a higher vibration frequency and amplitude more effectively increased for increasing SA muscle activation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.7 s.250
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• pp.865-872
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• 2006

High frequency induction welding is widely employed for longitudinal seam welding of small scale tubes and pipes because of its relatively high processing speed and efficiency. This research is aimed at understanding the variables that affect the quality of the high frequency induction welding. The welding variables include the welding frequency, weld speed, V-angle and tube thickness. Temperature distribution of the tube is calculated through three dimensional coupled electromagnetic and thermal FE analysis. The skin and proximity effects are considered in the electromagnetic analysis. The influence of the impeder is also analyzed. The effects of the operating welding variables on the temperature distribution are investigated quantitatively by exhibiting the heat affected zone (HAZ). The results explain the mechanism of significant enhancement of welding efficiency when the impeder is used. The proper welding conditions without the overheated edge are obtained through FE analysis.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.140-143
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• 1988

In this study, so called high frequency cycloconverter which converts commercial so power source directly to high frequency power source is proposed. In this system, the circulating current play very important role. Its state and magnitude effects on system characteristics. This paper deals with the control method of the circulating current and side band component analysis of high frequency side current which is produced by it.

• Journal of Korean Medicine for Obesity Research
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• v.6 no.2
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• pp.75-83
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• 2006

Objectives : This study was performed to identify the effects of high frequency therapy on localized obesity. Methods : This trial was carried out in 12 volunteers. Volunteers were divided into 3 groups; upper arm group (n=4), thigh group (n=4) and abdomen group (n=4) according to local obesity type. Body weight and body fat were measured by Inbody 720 and CT (Computed Tomography) immediately before and following high frequency therapy. Diathermy was performed twice a week for 4 weeks for a total of 8 treatments. Results : In the upper arm group, body weight, body fat mass, fat area by CT scan and circumference were increased after treatment but not significantly (p>0.05). In the thigh group, body weight, body fat mass and circumference were decreased and fat area by CT scan was increased but both not significantly (p>0.05). In the abdomen group, significant differences were not found despite decreases in body weight, body fat mass, visceral fat and subcutaneous fat after diathermy (p>0.05). Conclusions : There was no significant effects of high frequency therapy on localized obesity.

• Physical Therapy Korea
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• v.4 no.2
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• pp.36-50
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• 1997

The purpose of this study was to compare the effects of high intensity, high frequency microcurrent electrical neuromuscular stimulation(MENS) of auricular and somatic acupuncture points and low intensity, low frequency microcurrent electrical neuromuscular stimulation(MENS) of auricular and somatic acupuncture points on experimental pressure threshold at the elbow according to the time. Fifty healthy adults, aged 19 to 26 years, were assigned randomly to one of five groups: 1) the high intensity, high frequency somatic group(n=10) received MENS to somatic acupuncture points, 2) the high intensity, high frequency auricular group(n=10) received MENS to auricular acupuncture points, 3) the low intensity, low frequency somatic group(n=10) received MENS to somatic acupuncture points, 4) the low intensity, low frequency somatic group(n=10) receive MENS to somatic acupuncture points, and 5) the placebo group(n=10) received placebo treatment and served as controls. Pressure threshold was measured before, after, 5 minutes, 10 minutes and 15 minutes. Pressure threshold has increased significantly(p<.05) in the high intensity, high frequency auricular group following treatment after 5 minutes, with no statistically significant differences in pressure threshold change scores among five groups, Only the high intensity, high frequency auricular group demonstrated statistically significant change score in pressure threshold following treatment after, 5 minutes, 10 minutes and 15 minutes after compared to the placebo group. The results indicated that MENS applied to the high intensity, high frequency auricular group increases pressure threshold.

• Advances in aircraft and spacecraft science
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• v.4 no.5
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• pp.543-553
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• 2017

Vibration is a source of performance degradation in all optical imaging systems. Performance of high resolution remote sensing payloads is often limited due to satellite platform vibrations. Effects of Linear and high frequency sinusoidal vibrations on the system MTF are known exactly in closed form but the low frequency vibration effects is a random process and must be considered statistically. Usually the vibration MTF budget is defined based on the mission requirements and the overall MTF limitations. For analyzing low frequency effects, designer must know all the systems specifications and parameters. With a good understanding of harmful vibration frequencies and amplitudes in the system preliminary design phase, their effects could be removed totally or partially. This procedure is cost effective and let the designer to eliminate just harmful vibrations and avoids over-designing. In this paper we have analyzed the effects of low-frequency platform vibrations on the payload's modulation transfer function. We have used a statistical analysis to find the probability of imaging with a MTF equal or greater than a pre-defined budget for different missions. The worst and average cases have been discussed and finally we have proposed "look-up figures". Using these look-up figures, designer can choose the electro-optical parameters in such a way that vibration effects be less than its pre-defined budget. Furthermore, using the results, we can propose a damping profile based on which vibration frequencies and amplitudes must be eliminated to stabilize the payload system.

• Journal of Acupuncture Research
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• v.20 no.1
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• pp.177-190
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• 2003

Objective : This study was intended to investigate the analgesic effects of electroacupuncture(EA) on mechanical allodynia according to the frequency and intensity of EA. Also to know if mechanical allodynia and the analgesic effects of EA is related to the sympathetci nervous system and/or the purinergic system. Methods : mechanical allodynia-induced rats were produced by resecting S1-S2 nerve. The zusanli(ST36) was used for acupoint and the rats were divided into 4 groups. Each group was given different stimuli[low frequency low intensity-EA(LFLI-EA), low frequency high intensity-EA(LFHI-EA), high frequency low intensity-EA(LFHI-EA), high frequency high intensity-EA(HFHI-EA)]. Futhermore, to make sympathectomy6-OHDA and phentolamine were administered intraperitonially and the concentration of norepinephrine(NE) were measured. As a ATP blocker, suramin was applied for this study. Results : Comparing to control group, each of the 4 groups(LFLI-EA, LFHI-EA, HFLI-EA, HFHI-EA) showed a significant reduction of response frequency of mechanical allodynia. LFHI-EA was more effective than that of LFLI-EA. The LFHI-EA group also had longer lasting effects from the stimulation than the other groups. Sympathectomy didn't show any reduction of response frequency of mechanical allodynia.(Each n=6, n=4). Nor did both sympathectomy and ATP block. The response frequency wasn't reduced by sympathectomy or by sympathectomy and ATP block, but was significantly reduced with LFHI-EA Conclusions : These results suggest that EA has a significant analgesic effect on mechanical allodynia which has no connection with NE and/or ATP.

• Journal of Korean Home Economics Education Association
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• v.12 no.3
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• pp.105-114
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• 2000

The purpose of this study was to investigate the effects of instructional multi-media in Home Economics Education perceived by teachers. The data for this research were attained from 139 middle & high school teachers of Home Economics. The data were analyzed by frequency of distribution, mean, stand deviation. t-test and analysis of variance, scheffe test with SPSSWin 7.5 program. The results of this study are as follows: The effects of instructional multi-media were composed of four dimensions in this study; need, frequency of use, pros and cons. 1. From these four dimensions, the need has the highest and the frequency of use has the lowest score. 2. The effects of instructional multi-media are significantly related to personal & environmental characteristics. 1)Need of the instructional multi-media effects is significantly different according to age, experience of computer education and possession of a computer at home. Low and high age groups are higher in the need of the instructional multi-media effects score than middle group age and the more experience of computer education and possession of a computer at home are higher in that score. 2) Frequency of use is significantly different according to LAN system in school. The higher score of frequency of use is in a LAN system’s school. 3) Pros of the instructional multi-media effects is significantly different according to the level of education, experience of computer education and the type of school. Undergraduate high school teachers and the lower o experience of computer education are higher in the pros of the instructional multi-media effects score. 4) Cons of the instructional multi-media effects is significantly different according to the level of education. Graduate teachers are higher in the cons of the instructional multi-media effects score.