• Transactions of the Korean Society of Mechanical Engineers
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• v.8 no.6
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• pp.591-598
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• 1984

The results of measurements showing normal vibrations and rubbing noise generated during unlubricated smooth sliding between metal surfaces are presented. The measurements were made on pin-on-disc type apparatus instrumented with piezoelectric acceleration transducers and microphones. Spectral analysis of the both signals up to frequency of 10kHz indicates that they are closely correlated. The major components of both signals in this frequency range are primarily associated with the normal contact vibrations which are excited by surface irregularities being swept through the contact region during sliding. As an approximation to the seismic input of surface irregularities, an effective surface wavenumber spectrum was assumed in the form of an inverse vibration and noise measurements for a number of surface finishes and mean loads. The predominant frequency component of which levels of the normal vibration and noise are close to overall levels of the both signals is induced by contact resonance between the two bodies and its frequency can be calculated from the Hertzian theory.

• The Korean Journal of Community Living Science
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• v.24 no.3
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• pp.411-427
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• 2013

To investigate the comparison of dietary status and health behaviors according to obesity, 239 male workers were selected and classified as normal (18.5-22.9 27.2%), overweight (23-24.9, 37.7%), and obese (25-29.9, 35.2%) by body mass index ($kg/m^2$). The SAS (ver. 9.2) program was used and verified by the chi-square and f-value methods. Drinking frequency(2-3 times a week) was higher in normal males(45.3%), but not as high as in obese males (48.1%) (p<0.001). Smoking frequency and amount were the highest in overweight males, but not-quit-smoking was high in obese males(51.9%) (p<0.001). Exercise time was longer in normal males(108 minutes) than other groups(69 overweight males, and 82 obese males (p<0.01). Obese groups(73.8%) slept well (p<0.001), but overweight males(44.4%) showed less than 6 hours of sleep (p<0.01). Meal frequency differed by group(two meals a day 67.7% in normal males (p<0.001), no-snack 65.5% in obese males(p<0.001). The frequency of eating-out was once a day in normal males (38.5%), differed in the eating-out time (lunch(45.8%) in normal males, dinner in overweight males(52.1%) and obese males(59.5%) (p<0.01). Korean food (49.3%) was selected, but noodle differed by group(10.2% normal 21.5% obese (p<0.01). Self-perception of body differed from the body's actual condition(p<0.001). For weight control, exercise(56.4%) was practiced more than diet(18.6%). Nutrition knowledge was poor (correct answer rate was 36.7% in normal males, 41.7% in overweight males, and 46.7% in obese males). For eating attitudes, obese males answered more in "flexible to change eating habits", "supplemented when poor eating"(p<0.001), normal responded in "impact on nutrition to health", "try new food for health"(p<0.01). From these results, it is evident that male workers, especially overweight ones, must work to learn more about health and nutrition so as to combat chronic diseases.

• The Journal of Korean Obstetrics and Gynecology
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• v.28 no.3
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• pp.30-39
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• 2015

Objectives This study aims to analyze Heart Rate Variability (HRV) in women after missed abortion compared with healthy women Methods We studied 35 women who visited Kang-Nam Kyung-Hee Korean Hospital after missed abortion from 01 January 2012 to 28 February 2015 (missed abortion group) and 35 normal women visiting medical examination center from 1 January 2014 to 31 December 2014 (Normal Group). We measured HRV of each women and investigated the difference of HRV between two groups. Results The standard deviation of NN intervals (SDNN) in Missed abortion group is lower than normal group. The square root of the mean square difference of successive NNs (RMSSD) in Missed abortion group is lower than normal group. However there was no significant difference. Total Power (TP) and Low frequency power (LF) is significantly lower in Missed abortion group compared with normal group. High frequency power (HF), Very low frequency power (VLF) and LF/HF ratio in missed abortion group is lower than normal group. but There was no significant difference. Conclusions Missed abortion group is lower in function of overall autonomic nervous system, especially sympathetic nerve.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.9 no.1
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• pp.11-16
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• 1998

Background and Objectives : Electrolarynx has been used as one of the methods of rehabilitation for the laryngectomees. Previous electrolarynx could not alter frequency and intensity simultaneously. This institute developed an electrolarynx named "Evada" using FSR(force sensing resistor) sensor, which can control the frequency(and/or intensity) simultaneously. This study was performed for the normal control and laryngectomees with three types of electrolarynx (Evada, Servox-inton, Nu-vois) to reveal functional characteristics of Evada Materials and Methods : five laryngectomees and five normal adults were made to express there sentences(discriptive sentence, "You stay here" ; question sentence, "You stay here？" ; exclamation sentence, "You!! stay here!"), using three types of electrolarynx. Frequency change and intensity change from first and last vowel was calculated in three sentences and analyzed statistically by paired T-test. Results : The frequency change in the question sentence and exclamation sentence was more prominent in Evada than in Servox-inton and Nu-vois. The intensity change in the question sentence and exclamation sentence was also more prominent in Evada than in Servox-inton and Nu-vois. Conclusions : Evada could control frequency and intensity simultaneously and control degree of frequency(and/or intensity) according to the pressing force into the button. Evada could adjust continuously frequency and intensity during conversation. So, Evada is better in producing intonation and contrastive stress than Nu-vois and Servox-inton.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2004.04a
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• pp.49-56
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• 2004

Model updating is a very active research field, in which significant efforts has been invested in recent years. Model updating methodologies are invariably successful when used on noise-free simulated data, but tend to be unpredictable when presented with real experimental data that are-unavoidably-corrupted with uncorrected noise content. In this paper, Reanalysis using frequency response functions for correlating and updating dynamic systems is presented. A transformation matrix is obtained from the relationship between the complex and the normal frequency response functions of a structure. The transformation matrix is employed to calculate the modified damping matrix of the system. The modified mass and stiffness matrices are identified from the normal frequency response functions by using the least squares method. One simulated system is employed to illustrate the applicability of the proposed method. The result indicate that the damping matrix of correlated finite element model can be identified accurately by the proposed method. In addition, the robustness of the new approach uniformly distributed measurement noise Is also addressed.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.453-456
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• 2005

Significance verification of electric fabric compared with existing electrode is very useful for the wearable and ubiquitous healthcare. In this paper, we verified the significance between Ag/AgCl electrode and electric fabric in dry-normal condition through heart rate variability analysis. We can find 98 % or more similarity about low frequency and high frequency which is important parameter for the heart rate variability analysis between two different electrodes in experiment. From this result, we confirmed that the power spectral density of low frequency, high frequency component from the electric fabric has high similarity compared with the result of heart rate variability from Ag/AgCl electrode in dry-normal condition.

• Nuclear Engineering and Technology
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• v.56 no.4
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• pp.1454-1459
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• 2024

Researchers have applied theoretical and CFD models for years to analyze the fluidelastic instability (FEI) of tube arrays in steam generators and other heat exchangers. The accuracy of each approach has typically been evaluated using the discrepancy between the experimental critical flow velocity and the predicted value. In the best cases, the predicted critical flow velocity was within an order of magnitude comparable to the measured one. This paper revisits the quasi-steady approach for damping controlled FEI in a normal triangular array with a pitch ratio of P/d = 1.375. The method addresses the fluidelastic frequency at the stability threshold as an input parameter for the approach. The excellent agreement between the estimated stability thresholds and the equivalent experimental results suggests that the fluidelastic frequency must be included in the quasi-steady analysis, which requires minimal computing time and experimental data. In addition, the model allows a simple time delay analysis regarding flow convective and viscous effects.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.5
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• pp.626-633
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• 2007

This study was conducted to determine the eating habits of obese elementary school students residing in Iksan city, in June 2006 using 1167 participants(obese: 233, normal weight: 934). The results are summarized as follows. The average age was 12 years-old in both the obese and normal weight groups. The average BMI, ideal body weight and obesity index in the obese and normal weight groups were $24.8kg/m^2$, 39.8 kg, and 32.5% and $18.2kg/m^2$, 37.7 kg and -1.4%, respectively. Regarding the number of subject who acknowledged their physical build, the obese group was highest(88.9%) in stating obese or extremely obese, while the normal group was highest(71.5%) in stating they were normal weight. For the frequency of eating breakfast, the obese group the results were: "eating it everyday"(69.1%) and $"3{\sim}4\;times/week"$ (13.7%), while in the normal weight group, the highest response was "eating it everyday"(75%) and the lowest response was "never eat it"(4.1%). In terms of having breakfast with someone, there were slight differences for eating alone between the obese group(17.4%) and normal group(12.4%) and also between the obese group(19.6%) and normal group (39.6%) for eating with parents. There were considerable gaps in the association of eating habits with weight such as having irregular meals in the obese group(52.4%) and having regular meals in the normal group(61.1%). The frequency of having snacks was different by the rate of obesity, where 65.9% of the obese group, and 57.8% of the normal group had snacks more than once. There were significant differences in the practice of controlling intake with the obese group at 77.3% and the normal group at 36.3%. There were high numbers regarding eating more than average in stressful times for both the obese group(10.3%) and normal group(7.7%). The results of this study show the prevalence of obesity in Iksan, and proper nutrition education is currently needed. Moreover, the greater the level of obesity, the higher the frequency of skipping breakfast, eating alone, and eating irregular meals, and the more experience in attempting to control weight. To resolve the problems triggered by inappropriate food habits, proper food and eating methods to control weight should be included in nutrition education programs for elementary students.

• Physical Therapy Korea
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• v.6 no.2
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• pp.16-31
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• 1999

The purpose of this study was to assess the fatigue in lumbar and abdominal muscles in patients with chronic low back pain compared with normal subjects using spectral analysis with mean power frequency and median power frequency. The experimental group consisted of twenty subjects who had experienced chronic low back pain for over one year after the onset day. A control group consisted of twenty normal subjects with no history of low back pain. All subjects stood in an apparatus to perform sustained contraction in the lumbar and abdominal muscles for 30 seconds with 60% maximal voluntary isometric contraction (MVIC). The resulting electromyographic (EMG) recorded time serial data were transformed into frequency serial data by Fast Fourier Transformation (FFT). The results were as follows: 1) lumbar muscles measured, the frequency change ratio of both median power frequency and mean power frequency was significantly greater for experimental group compared with control group group (p<0.05). In measured two abdominal muscles (inferior rectus abdominis, obliquus externus abdominis) except superior rectus abdominis, the frequency change ratio of both median power frequency and mean power frequency was significantly greater for experimental group compared with control group (p<0.05). 2) In all three (longissimus thoracis, iliocostalis lumborum, multifidus) lumbar muscles measured, the initial frequency value of both median power frequency and mean power frequency was significantly lower for the experimental group compared with the control group (p<0.05). In the two (inferior rectus abdominis, obliquus externus abdominis) abdominal muscles measured (superior rectus abdominis not included), the initial frequency value of both median power frequency and mean power frequency was significantly lower for the experimental group compared with the control group (p<0.05). These results suggest that in patients with chronic low back pain there is a trend for more fatigue to occur in both lumbar and abdominal muscles than in the normal control group. This would seem to suggest that in treatment programs for patients with chronic low back pain, improvement of endurance in all trunk muscles should be considered.

• Journal of Plant Biotechnology
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• v.33 no.4
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• pp.257-262
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• 2006

The paper evaluated the behavior of in vitro culture responses from a diverse set of Indica rice (Oryza sativa L.) genotypes. Significant differences were found in embryogenic callus induction frequency, callus growth and plant regeneration frequency when mature embryos of 11 cultivars, breeding lines and land races were compared. Genotype as well as plant growth regulator influenced the plant regeneration frequency. Callus induction frequency was not correlated with callus growth as well as plant regeneration frequency. The regenerated plants could grow to normal, fertile plants after they were successfully established in soil.