• The Journal of Korean Physical Therapy
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• v.32 no.4
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• pp.210-216
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• 2020

Purpose: This study examined the effects of curl-up using XCO^® on trunk muscle activation in healthy adults. Methods: This study design was a single-blind randomized controlled trial. Twelve participants were enrolled in this study. The subjects were instructed to perform curl-up exercise in STCU (straight curl-up), LTCU (left twist curl-up), RTCU (right twist curl-up), TWCU (twist curl-up), and PPCU (power push curl-up). Electromyography was used to assess the percent maximal voluntary isometric contraction (%MVIC) of the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and erector spinae (ES) muscles. The data were analyzed using two-way ANOVA with a repeated measure. The statistical significance level was set to α=0.05 Results: The IO showed significant differences in the main effect of the group and the interactions between the group and exercise (p<0.05). In particular, the IO represented the interactions between group and exercise in the RTCU and PPCU (p<0.05). The RA, EO, and ES did not show significant interactions between the group and exercise (p>0.05). The RA, IO, and EO showed significant differences in the main effect of the group (p<0.05). The EO showed a significant difference in the main effect of exercise (p<0.05). Conclusion: These findings suggest that XCO^® can be used to increase the muscle activation of the internal oblique, which is the lumbar stabilizing muscle, when XCO^® is combined in the curl-up exercise with rotation. In the future, research on the intensity, frequency, and duration of XCO^® exercise will be needed according to the individual characteristics and preferences.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.2
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• pp.152-160
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• 2001

Six degrees of freedom measurement systems are required in many fields: Precision machine control. precision assembly, vibration analysis, and so on. This paper presents a new six degrees of freedom measurement system utilizing typical features of a diffraction grating. It is composed of a laser source, three position sensitive detectors, a diffraction grating target, and several optical components. Six degrees of freedom displacement is calculated kinematically from the coordinates of diffracted rays on the detectors. Optical measurement error was caused by the fact that a laser source had a Gaussian intensity distribution. This error was analyzed and compensated using simple equations. The performance of the compensation equation was verified in the experiment. The experimental results showed that the compensation equation could reduce the optical measurement error remarkably and the error in six degrees of freedom measurement less than $\pm$10$\mu$m for translation and $\pm$0.012$^{\circ}$for rotation.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.7 no.1
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• pp.50-55
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• 1996

Acoustic analysis study was performed on 20 normal subjects by speaking nonsense syllables composed of Korean bilabial stops$(/P, P^{\star}, P^{h}/)$ and their preceding and/or following vowel /a/ (that is, $[pa, p^{\star}a, p^{h}a, apa, ap^{\star}a, ap^{h}a]$) with an ultraminiature pressure, sensor. in their mouths. Speech materials were phonated twice, once with a moderate voice, another time with a loud voice. The acoustic signal and intraoral pressure were recorded simultaneously on computer. By these procedures, we were to measure the intraoral pressure, closure duration and VOT of Korean bilabial stops, and to compare the values one another according to the intensity of phonation and the position of the target consonants. Intraoral pressure was measured by the peak intraoral pressure value of Its wave closure duration by the time interval between the onset of intraoral pressure build-up and the burst meaning the release of closure ; Voice onset time(VOT) on by the time interval between the burst and the onset or glottal vibration. Heavily aspirated bilabial stop consonant /$p^h$/ showed the highest intraoral pressure value, unaspirated /$p^{\star}$/, the second, slightly aspirated /P/, the lowest. The syllable initial bilabial stops showed higher intraoral pressure than word initial stops, and the value of loudly phonated consonants were higher than moderate consonants. The longest closure duration period was that of /$p^{\star}$/ and the shortest, /P/, and the duration was longer in word initial position and in the moderate voice. In VOT, the order of the longest to shortest was $/{p^h}/, /p/, /{p^\star}/$, and the value was shorer when the consonant was in intervocalic position and when it was phonated with a loud voice.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.6
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• pp.513-519
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• 2016

In this study, dynamic vertical displacement of liquid in the tuned liquid column damper(TLCD) is measured by a laser Doppler vibrometer(LDV) to overcome limitations of existing sensors and to leverage noncontact sensing. Addressing advantages of noncontact measurements, operational principles of the LDV to measure velocity and displacement of a target object in motion is explained. The feasibility of application of the LDV to measurement of liquid motion in the TLCD is experimentally explored. A series of shake table tests with the TLCD are performed to determine requirements of application of the LDV. Based on the experimental results, it is proved that the LDV works under the condition of adding dye to the liquid by increasing the intensity of reflected laser and thus validity is verified by comparison with a conventional wave height meter.

• Wind and Structures
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• v.17 no.1
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• pp.43-68
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• 2013

The fluctuating wind induced vibration is one of the most important factors which has been taken into account in the design of long-span bridge due to the low stiffness and low natural frequency. Field measurement characteristics of sustained wind on structure site can provide accurate wind load parameters for wind field simulation and structural wind resistance design. As a suspension bridge with 1490 m main span, the Runyang Suspension Bridge (RSB) has high sensitivity to fluctuating wind. The simultaneous and continuously wind environment field measurement both in mid-span and on tower top is executed from 2005 up to now by the structural health monitoring system installed on this bridge. Based on the recorded data, the wind characteristic parameters, including mean wind speed, wind direction, the turbulence intensity, the gust factors, the turbulence integral length, power spectrum and spatial correlation, are analyzed in detail and the coherence functions of those parameters are evaluated using statistical method in this paper. The results indicate that, the turbulence component of sustain wind is larger than extremely strong winds although its mean wind speed is smaller; the correlation between turbulence parameters is obvious; the power spectrum is special and not accord with the Simiu spectrum and von Karman spectrum. Results obtained in this study can be used to evaluate the long term reliability of the Runyang Suspension Bridge and provide reference values for wind resistant design of other structures in this region.

• Resources Recycling
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• v.5 no.3
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• pp.37-43
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• 1996

The recovery of metals from printed circuit board(PCBs) scraps was investigated by utilizing a shape sorting method.After all electronic parts mounted on the board were removed. PCBs were pulverized to particles smaller than 1 mm by aswing hammer type impact mill in order to liberate metal components. Metals were separated from nonmetalliccomponents by an inclined vibrating plate (IVP). The metal separation efficiency was measured as a function of vihrationintensity and inclined angle. The maximum efficiency was obtained when IVP was operated at the vibration intensity(Kv)of 1.40 and the inclined angle of 10". The grade of the metal components was recovered from PCBs exceeding 90% byusing IVP.0% by using IVP.

• Journal of Power System Engineering
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• v.18 no.6
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• pp.180-185
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• 2014

Due to the larger and high-speed vessels recently constructed, output and speed of the engines for propulsion or power generation is increasing. These high-power and high-speed engine of the ship is becoming as a major contributor causing excessive noise and vibration. Other fittings as well as equipment installed on board, it makes equipment failure or other defect by resonance. This causes a lot of M/H(Man Hour) for repairs and the reliability of the company is invading even be negative because the clients give much comment. Thus, it's being studied for any fittings installed on board to maintain the safe operation and to prevent any problem during the performance in any operating conditions. In this study, it was investigated to solve these problems for the supports of the various fittings for easy installation-related support that each type of intensity and shape and manufacturing method using structural analysis program(DNV Nauticus Hull 3D Beam). Namely, it would be applied to the very large crude carriers in consideration of mechanics of materials of the support equipment by providing the fact that dynamics analysis of the structural characteristics of the equipment and the support of the production installation is easy and productivity can be high standards for geometry and thereby to simplify the analysis task to design changes at the same time and to minimize the reinforcement for the supports.

• Current Optics and Photonics
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• v.4 no.4
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• pp.286-292
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• 2020

Imaging through multicore fiber (MCF) is of great significance in the biomedical domain. Although several techniques have been developed to image an object from a signal passing through MCF, these methods are strongly dependent on the surroundings, such as vibration and the temperature fluctuation of the fiber's environment. In this paper, we apply a new, strong technique called deep learning to reconstruct the phase image through a MCF in which each core is multimode. To evaluate the network, we employ the binary cross-entropy as the loss function of a convolutional neural network (CNN) with improved U-net structure. The high-quality reconstruction of input objects upon spatial light modulation (SLM) can be realized from the speckle patterns of intensity that contain the information about the objects. Moreover, we study the effect of MCF length on image recovery. It is shown that the shorter the fiber, the better the imaging quality. Based on our findings, MCF may have applications in fields such as endoscopic imaging and optical communication.

• Physical Therapy Rehabilitation Science
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• v.7 no.4
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• pp.197-203
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• 2018

Objective: Independent walking is the most essential prerequisite to maintain quality of life in older persons. The purpose of this review was to investigate the effect of fall prevention strategies on fall risk for type 2 diabetes mellitus (T2DM) within community-dwelling older adults aged 65 and over. Design: A systematic review and meta-analysis. Methods: PubMed and three other databases were searched up to October 31st, 2018 and randomized controlled trials (RCTs) evaluating fall prevention strategies for fall risk in persons who were 65 years of age or above with T2DM were included. The review extracted the following information from each study selected: first author's surname, published year, country, study population, type of intervention, intensity of intervention, comparison, measurement variables, additional therapy, summary of results, and mean and standard deviation from selected studies. Results: This review selected fourteen RCTs with 460 older adults with diabetes mellitus. Of the 14 studies, the types of intervention used to improve the risk of falls were strengthening (5), aerobic exercises (2), multimodal exercises (4), one virtual reality exercise (1), whole body vibration with balance exercise (1), and Tai Chi exercise (1). Seven RCTs were eligible for the meta-analysis. Therapeutic interventions were more effective than the control group for the Timed Up-and-Go test (-1.11; 95% CI, -1.82 to -0.41) and the 6-minute Walk Test (-1.89; 95% CI, -8.33 to 4.54). Conclusions: The results of the review suggest that interventions to prevent fall risk in older adults with T2DM should focus on strengthening, balance, aerobic, and multimodal exercises.

• Journal of Digital Convergence
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• v.19 no.8
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• pp.345-350
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• 2021

In the explosive development of the beauty industry, skin care workers are negatively affected by their health and work attitudes due to excessive work intensity or excessive working hours, so there is an urgent need to study the working environment and job psychology. To this end, hypotheses were established and the main effects on skin care workers' job efficacy and job satisfaction in connection with manual technique were analyzed. As a result of the study, in the effect of the skin care manual technique on the skin care professional's sense of job efficacy, the scrutiny method had a significant effect, and in the effect on job satisfaction, the flexible method, the gait method, and the vibration method had a significant effect. In the skin care room, research and development of in-depth manual technique according to the purpose and scope of application of the customer is necessary for the skin care professional's job efficacy and job satisfaction as well as customer satisfaction. It is expected that it will be used as a basic data.