• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.447-456
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• 2009

The design comparison and flexural reliability analysis of continuous span composite plate girder bridges are performed. The girders are designed by the methods of allowable stress design (ASD) and load and resistance factor design (LRFD). For the LRFD design, the design specification under development mainly by KBRC, based on AASHTO-LRFD specification in case of steel structures, is applied with the newly proposed design live load which has been developed by analyzing domestic traffic statistics from highways and local roads. For the ASD based design, the current KHBDC code with DB-24 and DL-24 live loads is used. The longest span length for the 3-span continuous bridges with span arrangement ratio of 4:5:4 is assumed to be from 30 m to 80 m. The amount of steel, performance ratios, and governing design factors for the sections designed by the ASD and LRFD methods are compared. In the reliability analysis for the flexural failure of the sections designed by two methods, the statistical properties on flexural resistance based on the yield strength statistics for over 16,000 domestic structural steel samples are applied.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.3
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• pp.23-30
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• 2023

Background: The purpose of this study was to investigate the effects of joint mobilization and muscle strengthening exercises on neck function, range of motion, and muscle tone in patients with forward head posture. Methods: A total 32 subjects were divided into muscle strengthening exercise (n=16) and joint mobilization (n=16) who met the diagnostic criteria for the forward head posture, and the study method used the neck disability index (NDI) and BPM Pro to compare the range of motion. Results: As a result of the study, there was no significant difference between each group, and when looking at the differences before and after each group, there was a significant difference in neck pain in both groups. There was a significant difference in muscle tension in the joint mobilization group, but there was no significant difference in the muscle strengthening exercise group. In the range of joint mobilization, there was a significant difference in the range of left joint mobilization of the joint mobilization group, there was no significant difference in the range of right joint mobilization, and there was no significant difference in the range of joint mobilization of the muscle strengthening exercise group. Conclusion: The above results revealed that joint mobilization and muscle strengthening exercises were effective on neck function, range of motion, and muscle tone in forward head posture patients.

• PNF and Movement
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• v.21 no.3
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• pp.327-335
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• 2023

Purpose: Cerebellar injury can be caused by a variety of factors, including trauma, stroke, and tumor. Cerebellar injury can manifest in different clinical symptoms and signs depending on the size and location of the injury. The purpose of this study was to examine and compare the recovery patterns of each motor function by tracking the motor levels of patients with cerebellar injury. Methods: This study recruited 11 patients with quadriplegia resulting from cerebellar injury. The motricity index (MI), modified Brunnstrom classification (MBC), and functional ambulation category (FAC) methods were used to evaluate motor levels. The motor function evaluation was performed immediately after the onset of the condition and at intervals of one month, two months, and six months after onset. Results: The MI values of the upper and lower extremities and hand function (MBC) indicated severe paralysis in the early stages of onset. Compared to the onset time, significant motor function recovery was observed after 1, 2, and 6 months (p < 0.05). In contrast, there was no significant pattern of recovery between 1, 2, and 6 months after onset (p > 0.05). FAC indicated showed significant recovery at one month compared to onset (p<0.05), and there was also a significant difference between 1 and 2 months (p < 0.05). On the other hand, there was no significant difference in FAC between 2 and 6 months (p > 0.05). Conclusion: Patients with cerebellar injury showed significant recovery in functions related to muscle strength and voluntary muscle control one month after onset and gradually recovered further over the next six months. On the other hand, gait function, which is closely related to balance, showed a relatively slow recovery pattern from the beginning of the disease to the six month follow-up.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.3
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• pp.59-70
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• 2023

In order to predict low-level wind shear at Incheon International Airport (RKSI), a Low-Level Wind Shear prediction system (KMAP-LLWS) along the runway take-off and landing route at RKSI was established using Korea Meteorological Administration Post-Processing (KMAP). For the performance evaluation, the case of low-level wind shear cases calculated from Aircraft Meteorological Data Relay (AMDAR) from July 2021 to June 2022 was used. As a result of verification using the performance evaluation index, POD, FAR, CSI, and TSS were 0.5, 0.85, 0.13, and 0.34, respectively, and the prediction performance was improved by POD, CSI, and TSS compared to the Low-Level Wind Shear prediction system (LDPS-LLWS) calculated using the Korea Meteorological Administration's Local Data Assimilation and Prediction System (LDAPS). This means that the use of high-resolution numerical models improves the predictability of wind changes. In addition, to improve the high FAR of KMAP-LLWS, the threshold for low-level wind shear strength was adjusted. As a result, the most effective low-level wind shear threshold at 8.5 knot/100 ft was derived. This study suggests that it is possible to predict and respond to low-level wind shear at RKSI. In addition, it will be possible to predict low-level wind shear at other airports without wind shear observation equipment by applying the KMAP-LLWS.

• Structural Engineering and Mechanics
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• v.90 no.4
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• pp.371-390
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• 2024

Investigating the impact of openings on the structural behavior of ferrocement I-beams with two distinct types of reinforcing metallic and non-metallic meshes is the primary goal of the current study. Up until failure, eight 250x200x2200 mm reinforced concrete I-beams were tested under flexural loadings. Depending on the kind of meshes used for reinforcement, the beams are split into two series. A control I-beam with no openings and three beams with one, two, and three openings, respectively, are found in each series. The two series are reinforced with three layers of welded steel meshes and two layers of tensar meshes, respectively, in order to maintain a constant reinforcement ratio. Structural parameters of investigated beams, including first crack, ultimate load, deflection, ductility index, energy absorption, strain characteristics, crack pattern, and failure mode were reported. The number of mesh layers, the volume fraction of reinforcement, and the kind of reinforcing materials are the primary factors that vary. This article presents the outcomes of a study that examined the experimental and numerical performance of ferrocement reinforced concrete I-beams with and without openings reinforced with welded steel mesh and tensar mesh separately. Utilizing ANSYS-16.0 software, nonlinear finite element analysis (NLFEA) was applied to illustrate how composite RC I-beams with openings behaved. In addition, a parametric study is conducted to explore the variables that can most significantly impact the mechanical behavior of the proposed model, such as the number of openings. The FE simulations produced an acceptable degree of experimental value estimation, as demonstrated by the obtained experimental and numerical results. It is also noteworthy to demonstrate that the strength gained by specimens without openings reinforced with tensar meshes was, on average, 22% less than that of specimens reinforced with welded steel meshes. For specimens with openings, this value is become on average 10%.

• Journal of Korean Physical Therapy Science
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• v.31 no.2
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• pp.1-14
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• 2024

Background: Many patients with chronic low back pain have reduced movement due to pain. For that reason, muscle strength weakens, which leads to pain again. The pain caused by such a vicious circle is not only caused by structural problems, but also by physical function, activity disorder, or psychological depression due to biopsychosocial approaches and pain neuroscience education was applied as an intervention to find out its effect. Therefore, this study was experimented with to find out the effects of pain neuroscience education on pain, physical function, activity disorder, and depression in patients with chronic low back pain. Design: Randomized control trial Method: The study subjects were 39 patients with chronic low back pain, and the study subjects were randomized through computers to the experimental group applying pain neuroscience education and the control group applying only general physical therapy and myofascial release techniques, and the experiment was conducted for 4 weeks. Pressure Pain Threshold , Schober test, Korean Roland-Morris Disability Questionnaire, Korean Oswestry Disability Index, and Korean Depression Screening Assessment were measured. Results: As a result of the study, there was no significant difference in pain neuroscience education compared to the group that applied only general physical therapy and myofascial release techniques in both lumbar pressure pain thresholds, Schober test, Korean Roland-Morris disability questionnaire, and Korean Oswestry disability questionnaire. However, the Korean Depression Screening Assessment which is the result of measuring depression, showed significant results(p<0.05). Conclusion: Therefore, it is believed that it can be a way to mediate the psychological part through pain neuroscience education for patients with chronic low back pain in the future.

• Journal of Korean Physical Therapy Science
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• v.31 no.2
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• pp.41-51
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• 2024

Background: The purpose of this study was to identify the effect of home-based exercise program in elderly with chronic diseases on balance, activities of daily living, depression and quality of life. Design: One group pretest-posttest design Methods: The subjects consisted of 21 elderly people over the age of 65 years with chronic diseases lived in seo-gu, Gwangju. Home-based exercise program was performed twice a week, for an hour, during 6 weeks under supervision of an experienced instructor. The home-based exercise program was structured to last a total of 1 hour, consisting of 10 minutes of warm-up, 30 minutes of main exercises, and 20 minutes of concluding exercises. For the warm-up, we performed range of motion, stretching, and flexibility exercises. The main exercises comprised of strength, weight-bearing and balance exercises, and endurance exercises. The concluding exercises were tailored to the individual's home environment and needs, including task-oriented daily living training such as getting up from bed, moving to the restroom, and walking indoors. The subjects were assessed before and after the exercise program with berg balance scale(BBS), Korean-version modified barthel index(K-MBI), euro quality of life questionnaire 5-dimensional classification(EQ-5D), and geriatric depression scale short form-Korea(GDSSF-K). The collected data was analyzed using SPSS Win 18.0 program. Results: The results showed statistically significant difference in all domains of the BBS, K-MBI, EQ-5D, GDSSF-K after the exercise program. Conclusion: These results suggest that Home-based exercise program has resulted in a significant improvement on ADL, depression and quality of life in elderly with chronic diseases.

• Journal of Korean Medicine Rehabilitation
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• v.34 no.3
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• pp.107-117
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• 2024

The objective of this study is to report the clinical effects of applying an integrated rehabilitation protocol to four patients with traumatic cervical spinal cord injuries. The treatments applied included acupuncture, cupping and moxibustion, chuna manual therapy, functional electrical stimulation, and other physical therapies. The evaluation methods included American Spinal Injury Association Impairment Scale, functional independence measure (FIM), modified Barthel index (MBI), numeric rating scale (NRS) and other scales. All patients presented marked improvements in FIM, MBI, NRS and other scales, along with increased muscle strength in the manual muscle test. The application of our protocol resulted in clear clinical benefits and enhanced the recovery and quality of life for the patients in this study.

• Journal of the Korean earth science society
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• v.45 no.4
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• pp.318-326
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• 2024

Black ice, a thin and nearly invisible ice layer on roads and pavements, poses a significant danger to drivers and pedestrians during winter due to its transparency. We propose an efficient black ice detection system and technique utilizing Global Positioning System (GPS)-reflected signals. This system consists of a GPS antenna and receiver configured to measure the power of GPS L1 band signal strength. The GPS receiver system was designed to measure the signal power of the Right-Handed Circular Polarization (RHCP) and Left-Handed Circular Polarization (LHCP) from direct and reflected signals using two GPS antennas. Field experiments for GPS LHCP and RHCP reflection measurements were conducted at two distinct sites. We present a Normalized Polarized Reflection Index (NPRI) as a methodological approach for determining the presence of black ice on road surfaces. The field experiments at both sites successfully detected black ice on asphalt roads, indicated by NPRI values greater than -0.1 for elevation angles between 45° and 55°. Our findings demonstrate the potential of the proposed GPS-based system as a cost-effective and scalable solution for large-scale black ice detection, significantly enhancing road safety in cold climates. The scientific significance of this study lies in its novel application of GPS reflection signals for environmental monitoring, offering a new approach that can be integrated into existing GPS infrastructure to detect widespread black ice in real-time.

• Steel and Composite Structures
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• v.52 no.3
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• pp.357-376
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• 2024

In this paper, weakly bonded ultra-high-strength steel bars (UHSS) were used as longitudinal reinforcement in recycled aggregate concrete shear walls to achieve resilient performance. The study evaluated the repairability and hysteresis performance of shear walls before and after retrofitting. Quasi-static tests were performed on recycled aggregate concrete (RAC) and steel fiber reinforced recycled aggregate concrete (FRAC) shear walls to investigate the reparability of resilient shear walls when loaded to 1% drift ratio. Results showed that shear walls exhibited drift-hardening properties. The maximum residual drift ratio and residual crack width at 1% drift ratio were 0.107% and 0.01mm, respectively, which were within the repairable limits. Subsequently, shear walls were retrofitted with bonded X-shaped CFRP strips and steel plates wrapped at the bottom and retested. Except for a slight reduction in initial stiffness, earthquake-damaged resilient shear walls retrofitted with a composite method still had satisfactory hysteresis performance. A revised damage assessment index D, has been proposed to assess of damage degree. Moreover, finite-element analysis for the shear wall before and after retrofit retrofitting was established in OpenSees and verified with experimental results. The finite element results and test results were in good agreement. Finally, parametric analysis was performed.