• Steel and Composite Structures
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• v.33 no.6
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• pp.849-864
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• 2019

One way to achieve sustainable construction is to reduce concrete consumption by use of more sustainable and higher strength concrete. Modern building codes do not cover the use of ultra-high strength concrete (UHSC) in the design of composite structures. Against such background, this paper investigates experimentally the mechanical properties of steel fibre-reinforced UHSC and then the structural behaviors of UHSC encased steel (CES) members under both concentric and eccentric compressions as well as pure bending. The effects of steel-fibre dosage and spacing of stirrups were studied, and the applicability of Eurocode 4 design approach was checked. The test results revealed that the strength of steel stirrups could not be fully utilized to provide confinement to the UHSC. The bond strength between UHSC and steel section was improved by adding the steel fibres into the UHSC. Reducing the spacing of stirrups or increasing the dosage of steel fibres was beneficial to prevent premature spalling of the concrete cover thus mobilize the steel section strength to achieve higher compressive capacity. Closer spacing of stirrups and adding 0.5% steel fibres in UHSC enhanced the post-peak ductility of CES columns. It is concluded that the code-specified reduction factors applied to the concrete strength and moment resistance can account for the loss of load capacity due to the premature spalling of concrete cover and partial yielding of the encased steel section.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.6
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• pp.32-40
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• 2000

In this paper, we proposed a wavelet-based digital watermarking algorithm using human visual system and subband-adaptive threshold. After the original image is transformed by discrete wavelet transform, the perceptually significant coefficients of the each subband excluding the lowest level subbands are utilized to embed the watermark. To select perceptually significant coefficients for each subband, we use subband-adaptive threshold. For the selected coefficients in the high frequency subbands, the watermark is embedded using HVS. For those of the baseband, the watermark is embedded by conventional embedding method. We tested the performance of the proposed algorithm compared with conventional watermarking algorithm by computer simulation. The experimental results show that the proposed watermarking algorithm is less visible to human eyes and more robust to image compressions, image processings, and geometric transformations than the conventional algorithm.

• Journal of Korea Multimedia Society
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• v.15 no.9
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• pp.1102-1111
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• 2012

In this paper, we propose a robust watermarking method against geometric attack even though the watermarked image is partially damaged. This method consists of standard image normalization which transforms any image into a predefined standard image and embedding watermark in DCT domain of standard normalized image using spread spectrum technique. The proposed standard image normalization method has an improvement over existing image normalization method, so it is robust to partial damage and geometric attack. The watermark embedding method using spread spectrum technique also has a robustness to image losses such as blurring, sharpening and compressions. In addition, the proposed watermarking method does not need an original image to detect watermark, so it is useful to public watermarking applications. Several experimental results show that the proposed watermarking method is robust to partial damage and various attacks including geometric deformation.

• Journal of Korea Multimedia Society
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• v.15 no.8
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• pp.1017-1030
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• 2012

Most watermarking schemes for video contents protection have been studied to increase watermark's robustness and invisibility against such compressions and many kinds of signal processing after embedding copyright information to the original contents. This paper proposes an active watermarking that infect watermark to contents in the video decoding process using embedded infectious watermark and control signals from a video encoder side. To achieve this algorithm, we design a kernel based watermarking in video encoder side that is possible to recover the original contents and watermark in watermark detection procedure perfectly. And then, by reversible de-watermarking in video decoder side, we design the active watermark infection method using detected watermark and control signal. This means that our system can provide secure re-distributions of video contents without any quality degration and watermark bit error against transcoding or re-encoding processing. By experimental results, we confirmed that the embedded watermark was infected by video contents and codec perfectly without any declines of compression ratio and video quality.

• Journal of Internet Computing and Services
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• v.8 no.1
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• pp.133-142
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• 2007

Large database processing is one of the most important technique in the information society, Since most large database is regionally distributed, the distributed database processing has been brought into relief. Communications and data compressions are the basic technologies for large database processing. In order to maximize those technologies, the execution time for the task, the size of data, and communication time between processors should be considered. In this paper, the dataflow scheme and vertically layered allocation algorithm have been used to optimize the distributed large database processing. The basic concept of this method is rearrangement of processes considering the communication time between processors. The paper also introduces measurement model of the execution time, the size of output data, and the communication time in order to implement the proposed scheme.

• The Korean Journal of Emergency Medical Services
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• v.23 no.3
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• pp.67-81
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• 2019

Purpose: The purpose of this study was to compare the difference in compression quality and fatigue levels in a rescuer for three different hand techniques used in cardiopulmonary resuscitation (CPR). Methods: The participants were paramedic students at the basic life support provider level. The hands-only CPR was performed for 10 minutes for each of the three hand techniques without disruption, and the quality of chest compressions and fatigue levels were analyzed. Results: There was no difference between the sexes in the chest compression quality and the physiologic parameters before and after compression. Among the quality indexes of chest compression with each of the techniques performed for 10 minutes, the mean depth (p<.01) and mean accuracy (p=.000) of the compression were found to be higher in the five finger fulcrum technique, while the mean compression rate and relaxation accuracy showed no significant differences. Regarding fatigue levels, the five finger fulcrum technique caused lesser subjective fatigue as compared to other techniques (p<.05), although the heart rate and blood pressure revealed no difference. Conclusion: The five finger fulcrum technique was found to be better than the other techniques in terms of chest compression quality and subjective levels of fatigue, indicating that it should be used in CPR education.

• Clinical and Experimental Emergency Medicine
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• v.3 no.3
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• pp.148-157
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• 2016

Objective Our aim was to compare the compression quality, exercise intensity, and energy expenditure in 5-minute single-rescuer cardiopulmonary resuscitation (CPR) using 15:1 or 30:2 compression-to-ventilation (C:V) ratios or chest compression only (CCO). Methods This was a randomized, crossover manikin study. Medical students were randomized to perform either type of CPR and do the others with intervals of at least 1 day. We measured compression quality, ratings of perceived exertion (RPE) score, heart rate, maximal oxygen uptake, and energy expenditure during CPR. Results Forty-seven students were recruited. Mean compression rates did not differ between the 3 groups. However, the mean percentage of adequate compressions in the CCO group was significantly lower than that of the 15:1 or 30:2 group ($31.2{\pm}30.3%$ vs. $55.1{\pm}37.5%$ vs. $54.0{\pm}36.9%$, respectively; P<0.001) and the difference occurred within the first minute. The RPE score in each minute and heart rate change in the CCO group was significantly higher than those of the C:V ratio groups. There was no significant difference in maximal oxygen uptake between the 3 groups. Energy expenditure in the CCO group was relatively lower than that of the 2 C:V ratio groups. Conclusion CPR using a 15:1 C:V ratio may provide a compression quality and exercise intensity comparable to those obtained using a 30:2 C:V ratio. An earlier decrease in compression quality and increase in RPE and heart rate could be produced by CCO CPR compared with 15:1 or 30:2 C:V ratios with relatively lower oxygen uptake and energy expenditure.

• Journal of Convergence for Information Technology
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• v.9 no.11
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• pp.227-233
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• 2019

The purpose of this study is to evaluate the quality of chest compression by conducting comparison research between mechanical chest compressor(LUCAS) and manuale cardiopulmonary resuscitation(CPR) in a out-of-hospital environment and suggest effective advanced cardiac life support using mechanical chest compressors. For this, a out-of-hospital cardiac arrest was simulated with a team of 3 ambulance workers, and manuale CPR and CPR using LUCAS were performed on site and during transport in an ambulance. The research results are as follows: the comparison of manuale CPR between on site and in an ambulance revealed that on-site manuale CPR showed significant differences in the average compression depth, compression rate, and relaxation rate. Second, the comparison between manuale CPR and LUCAS in an ambulance showed significant differences in the average compression depth, compression rate, the number of compression per minute.

• Korean Journal of Applied Biomechanics
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• v.31 no.3
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• pp.220-225
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• 2021

Objective: The purpose of this study was to investigate the effect of levels of education on ground reaction force and center of pressure parameters during chest compression resuscitation. Method: Twenty male university students were divided into two groups; certified group (CG, n=10) and non-certified group (NCG, n=10). Two force plates were used to measure ground reaction force and center of pressure parameters during 30 times (three trials) chest compression resuscitation. Independent t-tests were used to compare ground reaction force and center of pressure parameters between two groups. An alpha level of 0.05 was used in all tests. Results: All chest-compression time parameters (total time, 1 systolic time, and diastolic time) in CG were significantly shorter than those in NCG (p<.05). Fy of the diastolic and Fz of the systolic in CG revealed significantly the larger GRF values and Fy of the systolic in CG showed significantly the smaller GRF value (p<.05). The standard deviation of Fz of the systolic and diastolic within the subject during 30 times chest-compression resuscitation revealed significantly the smaller values in CG (p<.05). Conclusion: First, CG performed chest compressions efficiently at an appropriate rate compared to NCG. Second, CG showed lower Fx and Fy values in both the mediolateral and anteroposterior axes compared to NCG, which reduced unnecessary chest-compression force consumption and minimized the movement in patients with cardiac arrest. Third, CG showed high Fz value of the systolic and low Fz value of the diastolic. Based on this, chest compression resuscitation was performed to increase the survival rate of cardiac arrest patients.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.155-161
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• 2018

The purpose of this study was to evaluate the efficacy of a multiple voice therapy technique ($SKMVTT^{(R)}$) using laughter for the treatment of various benign vocal fold lesions. To achieve this, 23 female patients diagnosed with vocal nodules, vocal polyp, and muscle tension dysphonia through videostroboscopy were enrolled in vocal hygiene and $SKMVTT^{(R)}$. All of the patients were treated once a week for 4 to 12 sessions. The GRBAS scale was used to confirm the changes in voice quality before and after the treatment. Acoustic analysis was performed to evaluate jitter, shimmer, NHR, fundamental frequency variation, amplitude variation, PFR, and dB range. Videostroboscopy was performed to confirm the changes in the laryngeal features before and after the treatment. After the $SKMVTT^{(R)}$, the results of the perceptual evaluation demonstrated that the G, R, and B scales significantly improved. An acoustic evaluation also demonstrated that jitter, shimmer, NHR, vAm, vFo, PFR, and dB range also significantly improved after the $SKMVTT^{(R)}$. In comparison to the videostroboscopic findings, the size of the vocal nodules and vocal polyp decreased or disappeared after the treatment. In addition, the size of the cuneiform tubercles decreased, the length of the aryepiglottic folds became longer, and the laryngeal findings of the supraglottic compressions improved after the $SKMVTT^{(R)}$. These results suggest that the $SKMVTT^{(R)}$ is effective in improving the vocal quality of patients with benign vocal fold lesions. In conclusion, it seems that laughter and inspiratory phonation suppressed abnormal laryngeal elevation and lowered laryngeal height, which seems to have the effect of improving hyperfunctional phonation.