• 한국체육학회지인문사회과학편
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• v.55 no.2
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• pp.643-655
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• 2016

The purpose of this study was to investigate biomechanical differences between young and old adults during downhill walking on a treadmill in order to understand the mechanisms of elderly falls. Eighteen healthy young females(YG: yrs: 21.17±1.5) and eighteen healthy old females(OG: yrs: 66.67±1.33) participated in this study. They were asked to walk at their preferred speed on a treadmill at level, 7.5° and 15° decline. OG walked more wobbly in the medial and lateral directions than YG(p<.05). As slope got steeper, OG had smaller ROM(range of motion) of ankle and knee joints compared with YG. However, there was no difference in ROM of the hip between OG and YG, but maximum extension angle of OG was smaller compared with YG(p<.05). Smaller extensor moment was generated on OG during downhill walking(p<.05). It was hypothesized that more risk factors would be found on older people compared to young people during downhill. However, older people actually walks with a safer strategy compared to young people during downhill. Finally, current findings about biomechanical characteristics of elderly walking would provide useful fundamental information for a follow-up study regarding the prevention of elderly fall during their daily life.

• Earthquakes and Structures
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• v.24 no.6
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• pp.455-475
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• 2023

The present study investigates the non-linear soil-pile interaction using three-dimensional (3D) non-linear finite element models. The numerical models were validated by using the results of extensive pile load and shaking table tests. The pile performance in liquefiable and non-liquefiable soil has been studied by analyzing the liquefaction ratio, pile lateral displacement (LD), pile bending moment (BM), and frictional resistance (FR) results. The pile models have been developed for the different ground conditions. The study reveals that the results obtained during the pile load test and shaking cycles have good agreement with the predicted pile and soil response. The soil density, peak ground acceleration (PGA), slenderness ratio (L/D), and soil condition (i.e., dry and saturated) are considered during modeling. Four ground motions are used for the non-linear time history analyses. Consequently, design charts are proposed depended on the analysis results to be used for design practice. Eleven models have been used to validate the capability of these charts to capture the soil-pile response under different seismic intensities. The results of the present study demonstrate that L/D ratio slightly affects the lateral displacement when compared with other parameters. Also, it has been observed that the increasing in PGA and decreasing L/D decreases the excess pore water pressure ratio; i.e., increasing PGA from 0.1 g to 0.82 g of loose sand model, decrease the liquefaction ratio by about 50%, and increasing L/D from 15 to 75 of the similar models (under Kobe earthquake), increase this ratio by about 30%. This study reveals that the lateral displacement increases nonlinearly under both dry and saturated conditions as the PGA increases. Similarly, it is observed that the BM increases under both dry and saturated states as the L/D ratio increases. Regarding the acceleration histories, the pile BM was reduced by reducing the acceleration intensity. Hence, the pile BM decreased to about 31% when the applied ground motion switched from Kobe (PGA=0.82 g) to Ali Algharbi (PGA=0.10 g). This study reveals that the soil conditions affect the relationship pattern between the FR and the PGA. Also, this research could be helpful in understanding the threat of earthquakes in different ground characteristics.

• Journal of the Korea Computer Graphics Society
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• v.29 no.3
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• pp.137-147
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• 2023

This paper presents a motion-capture-based projection VR system to explore the effectiveness of gamification in improving environmental awareness. We examine the key components of positive and negative VR game content and analyze the impact of individual and cooperative play methods on promoting sustainable behaviors. Our findings are as follows. Firstly, we discovered that the use of positive content in individual play mode was effective in improving awareness of the importance of recycling. Secondly, we confirmed that the use of positive content in cooperative play mode and the use of negative content in individual play mode were each effective in enhancing awareness of the seriousness of environmental pollution. Thirdly, we found that experiencing positive content first, followed by negative content, in individual play mode was effective in increasing interest in the environment. Based on these findings, we determined that adjusting the order of use of positive and negative content is more effective than simply using positive or negative content alone for improving environmental awareness. Moreover, considering the importance of recycling, the seriousness of environmental pollution, and the level of interest in the environment, we confirmed that individual play mode is effective and cooperative play mode can be more effective depending on the measure.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.821-829
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• 2006

Traffic load comprise primary input to pavement design causing pavement damage. therefore it should be proceeded suitable traffic load distribution modeling for pavement design and analysis. Traffic load have been represented by equivalent single axle loads (ESALs) which convert mixed traffic stream into one value for design purposes. But there are some limit to apply ESALs to other roads because it is empirical value developed as part of the original AASHO(American Association of State Highway Officials) road test. There have been many efforts to solve these problems. Several leading country have implemented M-E(Mechanistic-Empirical) design procedures based on mechanical concept. As a result, they established traffic load quantification method using load distribution model known as Axle Load Spectra. This paper details Axle Load Spectra and presents axle load distribution model based on normal mixture distribution function using truck load data collected by WIM system installed in national highway. Axle load spectra and axle load distribution model presented in this paper could be useful for basic data when making traffic load quantification plan for pavement design, overweight vehicle permit plan and pavement maintenance cost plan.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.2C
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• pp.109-120
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• 2006

SPT-Uphole test is a seismic field test using receivers on ground surface and a SPT (Standard penetration test) source in depth. Even though this method is simple and economic, it makes hesitate to apply in real field that it is difficult to obtain reliable travel time information of shear wave because of the characteristics of SPT impact source. To overcome this shortcoming, in this paper, modified SPT-Uphole method using two component surface geophones was suggested. Numerical analysis was performed using finite element method for understanding the characteristics of surface motion induced by in-depth vertical source, and comparison study of the various methods which determine the travel time information in SPT-Uphole method was performed. In result, it is thought that the most reasonable method is using the first local maximum point of the root mean square value signals of vertical and horizontal component in time domain. Finally, modified SPT-Uphole method using two component surface geophones was performed at the site, and the applicability in field was verified by comparing wave velocity profiles determined by the SPT-Uphole method with the profiles determined by SASW method and SPT-N values.

• PNF and Movement
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• v.21 no.3
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• pp.345-356
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• 2023

Purpose: The aim of this study was to investigate the effects of physical therapy combined with a virtual reality (VR) game on pain, quality of life (QOL), engagement, and knee function in post-knee-surgery patients. Methods: Twenty-four patients who had undergone knee surgery four weeks or more before the study were recruited. Two withdrew from the study during the four-week experimental period, and a total of 22 patients were included in the final analysis. Routine physical therapy consisting of electrostimulation (10 min.) and therapeutic massage (10 min.) was the base intervention for all groups. The experimental group (n = 10) was additionally exposed to a VR game intervention, while the control group (n = 12) underwent an intervention involving similar motions as the experimental intervention but with no VR. The intervention for the experimental group used the game Rig Fit Adventure on Nintendo switch. Both groups underwent their respective interventions 3 times a week (35 min. per session) for 4 weeks. Pain was assessed using the numeric rating scale (NRS), and QOL was assessed using the EuroQol five-dimensional five-level questionnaire (EQ-5D-5L). Engagement was assessed using the Korea flow state scale (K-FSS). Finally, knee movement and function were assessed based on knee flexion and extension, range of motion (ROM), and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Results: After the four-week physical therapy, both groups showed significant reductions in pain (on the NRS), increased knee ROM (flexion), better WOMAC scores, and increased EQ-5D-5L scores (p < 0.05), with the experimental group showing significantly better improvements in EQ-5D-5L and K-FSS scores (p < 0.05). Conclusion: The results of this study confirm that a VR-game-integrated intervention is effective for improving pain, QOL, engagement, and knee function in post-knee surgery patients and that VR-game-integrated interventions could be therapeutic alternatives for patients bedridden for prolonged periods with little motivation for rehabilitation.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.688-696
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• 2023

In the present study, free roll decay and resistance performances of fishing vessels were evaluated with the combinations and variations of in the parameters of appendages which are attached to improve motion performance of fishing vessels. Computational Ffluid Ddynamics was used to perform free roll decay and resistance analysis. The roll period and decay coefficient were derived by the variations in the combination and dimensions of the primary appendages of the bilge keel and the under keel. It was observed thatThe variations of in the length of the under keel did not significantly impact to the roll damping coefficient. Conversely, for the bilge keel, an increase in the length and angle resulted in an increase in the roll damping coefficient. Comparison of resistance performance was additionally assessed among the selected hulls with the appendages and bare hull. The resistance of the hull with the appendages was higher than that of the bare hull due owing to the changes of in the pressure on the surface of the hull and trim angle. Throughout the present study, the impact of appendage parameter and arrangement on the free roll decay and resistance performance of fishing vessels were was assessed,. which This will be beneficial for the application of appendages to fishing vessels.

• Journal of Veterinary Clinics
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• v.41 no.2
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• pp.71-78
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• 2024

Changes in elimination behavior, including urination and defecation, are common clinical signs of numerous disorders in cats. Therefore, this study attempted to automatically measure the elimination behavior of cats using the litter box and develop an early warning system for the guardian in case of abnormalities. To construct an early warning system for abnormal changes through cat elimination behavior, it consisted of a litter box, an automatic sensor for data collection and data wifi transmission, a server for data analysis, and a mobile phone app for result transmission and early warning. To establish the reference interval (RI), the elimination behavior was monitored for more than 2 weeks using a motion sensor within a litter box in 37 healthy cats and 19 diseased cats. The data were expressed as daily total visits, daily total stay duration, average stay duration per elimination, weekly total visits, and weekly total stay duration. Healthy cats showed median daily total visits of 3 times/day (RI 1.0-7.0) and daily total stay duration of 192 s/day (RI 8.0-452.0). For weekly data, the median total visits were 20 times/week (RI 3.0-35.25) and the median total stay duration was 1,147 s/week (RI 80.0-2,249.5). The average stay duration per elimination was 59 s/elimination (RI 4.67-132.0). Diseased cats showed more frequent elimination behavior than healthy cats (p < 0.001). Otherwise, for each elimination, diseased cats had shorter stay durations than healthy cats (p < 0.001). This study established the RIs of elimination behavior parameters (frequency and duration) in healthy cats. The present study might help guardians and veterinarians detect changes in elimination behaviors in diseased cats at an early stage.

• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.29-37
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• 2024

In this paper, we propose an efficient image processing system to detect and track the movement of specific objects such as patients. The proposed system extracts the outline area of an object from a binarized difference image by applying a thinning algorithm that enables more precise detection compared to previous algorithms and is advantageous for mixed-mode design. The binarization and thinning steps, which require a lot of computation, are designed based on RTL (Register Transfer Level) and replaced with optimized hardware blocks through logic circuit synthesis. The designed binarization and thinning block was synthesized into a logic circuit using the standard 180n CMOS library and its operation was verified through simulation. To compare software-based performance, performance analysis of binary and thinning operations was also performed by applying sample images with 640 × 360 resolution in a 32-bit FPGA embedded system environment. As a result of verification, it was confirmed that the mixed-mode design can improve the processing speed by 93.8% in the binary and thinning stages compared to the previous software-only processing speed. The proposed mixed-mode system for object recognition is expected to be able to efficiently monitor patient movements even in an edge computing environment where artificial intelligence networks are not applied.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.2
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• pp.47-53
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• 2024

Purpose : This study investigated the effects of concentric and eccentric contractions on muscle strength using an isokinetic dynamometer (ID) in college students in their 20s. It aimed to understand the impact of differences between the dominant and non-dominant sides on strength asymmetry and to elucidate the clinical implications of these differences to establish an appropriate posture and environment for patients. Methods : The experiment was conducted with 30 healthy adult participants. Prior to the experiment, participants underwent a warm-up targeting the shoulders, and efforts were made to eliminate factors that could potentially influence the measurement results. Subsequently, the maximum safe range of motion of shoulder joint abduction, extension, and flexion was measured using an isokinetic muscle function testing device. Muscle strength was assessed using concentric and eccentric contractions alternating between the dominant and non-dominant sides, and paired sample t-tests were used for the analysis. Results : There was no significant difference between bilateral peak torques for eccentric contraction in shoulder joint abduction, extension, and flexion (p>0.05). There was also no significant difference between bilateral peak torques for concentric contraction in shoulder joint abduction, extension and flexion (p>0.05). Conclusion : This study found no statistically significant difference in muscle strength between the dominant and non-dominant sides during concentric and eccentric contractions. However, previous studies have shown significant differences between the dominant and non-dominant sides during eccentric and concentric contractions during internal shoulder rotation in the general population, as well as significant differences in the upper trapezius muscle. Therefore, further research is needed to support the application of different intensities for bilateral muscle strengthening exercises in clinical practice.