• PNF and Movement
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• v.19 no.1
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• pp.137-146
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• 2021

Purpose: The study aimed to determine the effect of proprioceptive neuromuscular facilitation (PNF) lower trapezius muscle strengthening exercise on pain, cervical range of motion (ROM), and neck disability index (NDI) in patients with chronic neck pain. Methods: Following baseline measurements, the subjects (n = 30) with chronic neck pain were randomized into two groups: the PNF group (n = 15) that received PNF strength training of the lower trapezius muscles or a control group (n = 15) that received gentle palpation of the skin. Each group participated in the intervention for 30 min, three times per week for six weeks. The visual analogue scale for pain, ROM, and NDI of both groups were recorded at both pre- and post-intervention. Paired t-tests were used to determine significant changes in the post-intervention compared with pre-intervention, and independent t-tests were used to analyze differences in the dependent variables between the two groups. Results: After the six-week intervention, both groups experienced significantly decreased pain and NDI (p < 0.05) and significantly increased cervical flexion, extension, lateral flexion, and rotation ROM (p < 0.05). The PNF group that received PNF strength exercise of the lower trapezius muscles showed greater improvements in pain and NDI and cervical rotation of ROM than those of the control group (p < 0.05). Conclusion: These results suggest that the PNF lower trapezius strengthening exercise reduces neck pain and disability level and enhances cervical ROM in patients with chronic neck pain.

• Journal of Korean Physical Therapy Science
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• v.29 no.1
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• pp.47-54
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• 2022

Background: Plyometric exercise is an exercise exerting forceful power in a brief period using isotonic activation. It is effective to improve reaction of muscle, agility, endurance and athletics performance. Weight training is an exericse improving muscular strength, endurance and respirating ability applying diversely in frequency and load of exercise Plyometric exercise and Weight training is to facilitate the athletics performance though improving the function of lower limb muscle, there is a difference that Plyometic jump squats is the way to improve agility and Weight training is the way to improve muscular strength. Therefore, it is necessary to know how this difference effects on athletics performance as measuring ankle, ROM, and jumping ability. Design: Randomized controlled trial. Method: This study was conducted with the voluntary participation of 40 university students, who were randomly assigned to jump squat and calf raise groups (n=20 per group). For each subject, we measured the range of motion of the ankle joint before and after exercise, as well as a standing broad jump and vertical jump test performance. We compared the performance indices before and after exercises using paired t-tests, and between groups using independent-samples t-tests. Conclusions: Both jump squat and calf raise exercises improved ankle joint dorsiflexion and plantar flexion, as well as standing broad jump and vertical jump height performance. However, there were no significant differences before versus after exercise, or between exercise types. Although jump squats and calf raises have different purposes, it is thought that, in combination, these exercises improve performance more effectively than either alone, and that such a combined exercise program improves the quality of training in both the general public and athletes in various sports.

• Safety and Health at Work
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• v.11 no.4
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• pp.458-465
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• 2020

Background: The aim of this study was to analyze the interaction between neck and/or wrist pain and hand grip strength (HGS) and to investigate factors (age, sex, neck disorders, and carpal tunnel syndrome) influencing the HGS of industrial quality proofing workers (N = 145). Methods: Standardized questionnaires [Neck Disability Index (NDI), Boston Carpal Tunnel Questionnaire] were used to evaluate existing neck and/or wrist pain. HGS measurements were performed in different wrist positions. Results: Significant differences between participants with and without neck pain were found in different wrist positions, in neutral wrist position right [without neck pain (n = 48) 46.34 (43.39 - 49.30); with neck pain (n = 97) 38.46 (36.20 - 40.72), F_(1,144) = 16.82, p < 0.001, ŋ_p² = 0.11] and left [without neck pain 44.06 (41.19 - 46.94); with neck pain 37.36 (35.13 - 39.58), F_(1,144) = 12.70, p < 0.001, ŋ_p² = 0.08]. A significant difference between participants with and without wrist pain was found for neutral wrist position right [without wrist pain (n = 105) 42.53 (40.37 - 44.70); with wrist pain (n = 40) 37.24 (33.56 - 40.91), F_(1,144) = 6.41, p = 0.01, ŋ_p² = 0.04]. Regression analysis showed significant results especially for steps two (age and weight, NDI) and three (age and weight, NDI, Boston Carpal Tunnel Questionnaire) for neutral position right (R² = 0.355, R² = 0.357, respectively). Conclusion: Neck pain has an impact on HGS but should be evaluated in consideration of age and sex.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.6
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• pp.1149-1156
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• 2021

The Grover algorithm, which accelerates the brute force attack, is applicable to key recovery of symmetric key cryptography, and NIST uses the Grover attack cost for symmetric key cryptography to estimate the post-quantum security strength. In this paper, we estimate the attack cost of Grover's algorithm by implementing DES as a quantum circuit. NIST estimates the post-quantum security strength based on the attack cost of AES for symmetric key cryptography using 128, 192, and 256-bit keys. The estimated attack cost for DES can be analyzed to see how resistant DES is to attacks from quantum computers. Currently, since there is no post-quantum security index for symmetric key ciphers using 64-bit keys, the Grover attack cost for DES using 64-bit keys estimated in this paper can be used as a standard. ProjectQ, a quantum programming tool, was used to analyze the suitability and attack cost of the quantum circuit implementation of the proposed DES.

• Journal of the Korean Geotechnical Society
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• v.23 no.1
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• pp.67-76
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• 2007

Flat DMT penetration was analyzed using a finite element model based on a large strain formulation. The ABAQUS/Explicit, a commercial finite element method, was used to study the flat DMT penetration in soils. Then, because the very large mesh distortion occurred due to the penetration of flat DMT, the adaptive meshing technique was utilized to maintain a high quality mesh configuration. The undrained shear strength obtained from the flat DMT is estimated using only the horizontal stress index ($K_{D}$) and so it became necessary to examine using the analysis results obtained from the penetration of the flat DMT. Analysis results show that in normally consolidated region of $K_{D}=2$, the results obtained from the correlations proposed by Marchetti show good agreement with those estimated from the finite element method. The present analysis also shows that in overconsolidated region of $K_{D}>2$, the results obtained from the relationships proposed by Kamei and Iwasaki show good agreement with those provided by the penetration analysis.

• Advances in concrete construction
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• v.15 no.4
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• pp.251-267
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• 2023

In this paper, an experimental investigation is carried out to assess the inherent self-compacting properties of geopolymer mortar and its impact on flexural strength of thin-walled ferro-geopolymer box beam. The inherent self-compacting properties of the optimal mix of normal geopolymer mortar was studied and compared with self-compacting cement mortar. To assess the flexural strength of box beams, a total of 3 box beams of size 1500 mm × 200 mm × 150 mm consisting of one ferro-cement box beam having a wall thickness of 40 mm utilizing self-compacting cement mortar and two ferro-geopolymer box beams with geopolymer mortar by varying the wall thickness between 40 mm and 50 mm were moulded. The ferro-cement box beam was cured in water and ferro-geopolymer box beams were cured in heat chamber at 75℃ - 80℃ for 24 hours. After curing, the specimens are subjected to flexural testing by applying load at one-third points. The result shows that the ultimate load carrying capacity of ferro-geopolymer and ferro-cement box beams are almost equal. In addition, the stiffness of the ferro-geoploymer box beam is reduced by 18.50% when compared to ferro-cement box beam. Simultaneously, the ductility index and energy absorption capacity are increased by 88.24% and 30.15%, respectively. It is also observed that the load carrying capacity and stiffness of ferro-geopolymer box beams decreases when the wall thickness is increased. At the same time, the ductility and energy absorption capacity increased by 17.50% and 8.25%, respectively. Moreover, all of the examined beams displayed a shear failure pattern.

• Journal of Advanced Technology Convergence
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• v.2 no.2
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• pp.31-38
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• 2023

This study compares the correlation between muscle thickness (abdominal, quadriceps muscle) and how the muscle thickness affects the static balance when the static balance is measured in a standing position. The subjects of study were to select 29 subjects to find out what relationship muscle thickness had on the static balance when measuring muscle thickness and static balance. rectus femoris muscle thickness showed a significant correlation in statically balanced weight distribution index. In this study, only healthy men in their twenties were selected, and the results could not be generalized to other age groups. As a limitation of this study, muscle strength and peripheral vision were not measured, so it seems difficult to express the accuracy of the study and generalize the results. In future studies, the number of subjects and muscle strength should be measured to proceed with the study.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2C
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• pp.81-88
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• 2006

This study performed field and laboratory tests for poor subsoils taken in six regions of the country and determined undrain shear strength. Su values and preconsolidation pressure are predicted using Back Propagation neural network (BPNN) and the application of BPNN is verified. The result of BPNN shows that correlation coefficient between test and neural network result is over 0.9, which means high correlativity. Especially the neural network uses only 6 parameters such as natural water content, void ratio, specific gravity, rate of passing 200th sieve, liquid limits and plasticity index among various affecting factors to estimate value and the correlation coefficent is 0.93. The conclusions obtained in this paper are from the tests performed for poor subsoils taken in the several regions of the country. If there were more test results, the prediction and influence of various soil properties could be effectively performed by neural network.

• Geomechanics and Engineering
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• v.37 no.3
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• pp.223-241
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• 2024

Evaluating the performance of Tunnel Boring Machines (TBMs) stands as a pivotal juncture in the domain of hard rock mechanized tunneling, essential for achieving both a dependable construction timeline and utilization rate. In this investigation, three advanced artificial neural networks namely, gated recurrent unit (GRU), back propagation neural network (BPNN), and simple recurrent neural network (SRNN) were crafted to prognosticate TBM-rate of penetration (ROP). Drawing from a dataset comprising 1125 data points amassed during the construction of the Alborze Service Tunnel, the study commenced. Initially, five geomechanical parameters were scrutinized for their impact on TBM-ROP efficiency. Subsequent statistical analyses narrowed down the effective parameters to three, including uniaxial compressive strength (UCS), peak slope index (PSI), and Brazilian tensile strength (BTS). Among the methodologies employed, GRU emerged as the most robust model, demonstrating exceptional predictive prowess for TBM-ROP with staggering accuracy metrics on the testing subset (R² = 0.87, NRMSE = 6.76E-04, MAD = 2.85E-05). The proposed models present viable solutions for analogous ground and TBM tunneling scenarios, particularly beneficial in routes predominantly composed of volcanic and sedimentary rock formations. Leveraging forecasted parameters holds the promise of enhancing both machine efficiency and construction safety within TBM tunneling endeavors.

• Geomechanics and Engineering
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• v.37 no.1
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• pp.85-95
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• 2024

This study investigates the influence of nano-silica and basalt fiber content, curing duration, and freeze-thaw cycles on the static and dynamic properties of soil specimens. A comprehensive series of tests, including Unconfined Compressive Strength (UCS), static triaxial, and dynamic triaxial tests, were conducted. Additionally, scanning electron microscopy (SEM) analysis was employed to examine the microstructure of treated specimens. Results indicate that a combination of 1% fiber and 10% nano-silica yields optimal soil enhancement. The failure patterns of specimens varied significantly depending on the type of additive. Static triaxial tests revealed a notable reduction in the brittleness index (IB) with the inclusion of basalt fibers. Specimens containing 10% nano-silica and 1% fiber exhibited superior shear strength parameters and UCS. The highest cohesion and friction angle were obtained for treated specimens with 10% nano-silica and 1% fiber, 90 kPa and 37.8°, respectively. Furthermore, an increase in curing time led to a significant increase in UCS values for specimens containing nano-silica. Additionally, the addition of fiber resulted in a decrease in IB, while the addition of nano-silica led to an increase in IB. Increasing nano-silica content in stabilized specimens enhanced shear modulus while decreasing the damping ratio. Freeze-thaw cycles were found to decrease the cohesion of treated specimens based on the results of static triaxial tests. Specimens treated with 10% nano-silica and 1% fiber experienced a reduction in shear modulus and an increase in the damping ratio under freeze-thaw conditions. SEM analysis reveals dense microstructure in nano-silica stabilized specimens, enhanced adhesion of soil particles and fibers, and increased roughness on fiber surfaces.