• Korean Journal of Radiology
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• v.20 no.6
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• pp.939-946
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• 2019

Objective: To report our initial experience of percutaneous sacroplasty (PSP) with an interpedicular approach for treating painful sacral metastases involving multiple sacral vertebral bodies. Materials and Methods: This study prospectively enrolled 10 consecutive patients (six men and four women; mean age, 56.3 ± 13.8 years) who underwent PSP for painful sacral metastases involving multiple sacral vertebral bodies from March 2017 to September 2018. Visual analogue scale (VAS) scores, Oswestry disability index (ODI) values, and the number of opioids prescribed to the patients were assessed before and after PSP. The procedure duration, length of hospitalization, and complications were also recorded. Results: Mean VAS and ODI declined significantly from 6.90 ± 1.20 and 74.40 ± 5.48 before the procedure to 2.70 ± 1.34 and 29.60 ± 14.57 after the procedure, respectively (p < 0.01). The median number of opioids prescribed per patient decreased from 2 (interquartile range [IQR] 1-3) pre-procedure to 1 (IQR 0-3) post-procedure (p < 0.01). Nine of the 10 patients showed no or decreased opioid usage, and only 1 patient showed unchanged usage. The mean procedure duration was 48.5 ± 3.0 minutes. The average length of hospitalization was 4.7 ± 1.7 days. Extraosseous cement leakage occurred in three cases without causing any clinical complications. Conclusion: PSP with an interpedicular approach is a safe and effective treatment in patients with painful sacral metastases involving multiple sacral vertebral bodies and can relieve pain and improve mobility.

• Korea Journal of Hospital Management
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• v.28 no.4
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• pp.1-22
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• 2023

Purposes: The purpose of this study is to identify and analyze the factors that affect patients reusing non-face-to-face treatments at tertiary general hospitals. Methodology: We retrospectively analyzed a patient's reuse of non-face-to-face treatment from February 1, 2020, to December 31, 2021, at a tertiary general hospital in Seoul within one year of the first non-face-to-face treatment. A frequency analysis was conducted to identify the study subjects' demographic characteristics, treatment type characteristics, disease characteristics, and hospital use type characteristics. Also, across-analysis was conducted to verify the difference in non-face-to-face treatment reuse according to the characteristics a multiple logistic regression analysis was conducted to identify the factors affecting the reuse of non-face-to-face treatment by non-face-to-face treatment patients. Findings: The results of this study can be interpreted as indicating that the following groups are more likely tore use the non-face-to-face treatment: women, children, the elderly, Patients living far from the hospital, psychiatric patients, pediatric patients, medical benefits recipients, chronic patients, patients with mobility difficulties, and patients with high loyalty to hospitals. Practical Implications: When developing a non-face-to-face treatment system in the future, based on the results of this study, it is possible to target patients who prefer non-face-to-face treatment. And this study will be research material for vitalizing non-face-to-face treatment. In addition, the activation of the non-face-to-face treatment system will be an effective means for improving the quality of medical services and generating profits in hospitals in the future.

• Journal of The Korean Institute of Defense Technology
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• v.5 no.2
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• pp.17-22
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• 2023

In the midst of the development of science and technology based on the 4th industrial revolution, the ROK Army is moving forward with the ARMY TIGER 4.0 system, a ground combat system that combines future advanced science and technology. The system is developing around an AI-based hyper-connected ground combat system, and has mobility, intelligence, and networking as core concepts. Especially, the dronebot combat system is used as a compound word that refers to unmanned combat systems including drones and ground unmanned systems. In future battlefields, it is expected that the use of unmanned and artificial intelligence-based weapon systems will increase. During the transition to a complete unmanned system, it is a very important issue to ensure connectivity individual unmanned systems themselves or between manned and unmanned systems on the battlefield. This paper introduces the Multiplexer Allocation Problem (MAP) for effective command control and communication of UAV/UGV, and proposes a heuristic algorithm. In addition, the performance of the proposed algorithm is analyzed by comparing the solutions and computing time. Also, we discuss future research area for the MAP.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2359-2368
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• 2013

Cone penetration tests (CPTs) have been increasingly used for site characterizations. However, the site investigations using CPTs are often limited due to soil conditions depending on the cone size and capacity of the CPT system. The small sectional area of a miniature cone improves the applicability of the CPT system due to the increased capacity of the CPT system. A continuous intrusion system using a coiled rod allows fast and cost effective site investigation. In this study, the performance of the continuous intrusion miniature cone penetration test (CIMCPT) system has been evaluated by comparison tests with the standard CPT system at several construction sites in Korea. The results show that the CIMCPT system has a same performance with the CPT system and has advantages on the mobility and applicability. According to field verification tests for scale effect evaluation, the cone tip resistance evaluated by CIMCPT overestimates by 10% comparing to standard CPTs. A crawler mounted with the CIMCPT system has been implemented to improve accessibility to soft ground, and has shown improvement over the truck type CIMCPT system. Therefore, the improved CIMCPT system can be utilized as a cost effective and highly reliable soil investigation methodology to detect the depth of soft ground and to evaluate soil classification.

• Physical Therapy Korea
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• v.10 no.3
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• pp.109-126
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• 2003

This study was designed 10 investigate the effects of therapeutic gymnastic ball exercise on pain, flexibility, lumbar disability level and daily activity levels in male patients of the armed forces medical hospital who complain of chronic low back pain. Twenty-three males were placed in the experimental group and twenty-nine males were placed in the control group. All of the subjects were chosen on the basis of availability among in-patients who were diagnosed with low back pain. The control patients were matched to the experimental group and they were selected considering gender, pain duration and age. Gymnastic ball exercise therapy was developed by the author with the assistance of a rehabilitation specialist. Gymnastic ball exercise therapy includes muscle relaxation, flexibility, muscle strength and posture development exercises. The gymnastic ball exercise therapy was carried out by the experimental group three times a week for eight weeks. Before and after the experiments, the intensity of pain, the lumbar joint mobility (flexibility), the lumbar disability levels, and the daily activity levels of the subjects were measured, respectively. The intensity of pain and the lumbar disability levels were measured by the Visual Analogue Scale, the level of flexibility by a measurement ruler, and the level of disability by the Oswestry Low Back Pain Disability Scale. Data were analysed using a t-test, a paired t-test and an unpaired t-test. The results were as follows: 1. The intensity of pain in the lumbar spine in the experimental group was significantly decreased compared with that of the control group during the 4th week and 8th week. 2. The flexibility of the lumbar spine in the experimental group was significantly increased compared with that of the control group during the 4th week and 8 week. 3. The level of pain caused by anterior, posterior, left lateral and right lateral bending and by rotation in experimental group was significantly decreased compared with that of the control group. 4. The Oswestry Disability score of the experimental group was significantly increased compared with that of control group. These findings indicate that gymnastic ball exercise therapy could be effective in decreasing pain and lumbar disability, and increasing the daily activity levels and lumbar flexibility in patients with chronic low back pain. The study also suggests that gymnastic ball exercise therapy could be an essential factor for effective nursing intervention for patients suffering from chronic low back pain.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.157-167
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• 2020

Removing radioactive concrete is crucial in the decommissioning of nuclear power plants. However, this process generates radioactive aerosols, exposing workers to radiation. Although large amounts of radioactive concrete are generated during decommissioning, studies on the internal exposure of workers to radioactive aerosols generated from the cutting of radioactive concrete are very limited. In this study, therefore, we calculate the internal radiation doses of workers exposed to radioactive aerosols during activities such as drilling and cutting of radioactive concrete, using previous research data. The electrical-mobility-equivalent diameter measured in a previous study was converted to aerodynamic diameter using the Newton-Raphson method. Furthermore, the specific activity of each nuclide in radioactive concrete 10 years after nuclear power plants are shut down was calculated using the ORIGEN code. Eventually, we calculated the committed effective dose for each nuclide using the IMBA software. The maximum effective dose of ¹⁵²Eu constituted 83.09% of the total dose; moreover, the five highest-ranked elements (¹⁵²Eu, ¹⁵⁴Eu, ⁶⁰Co, ²³⁹Pu, ⁵⁵Fe) constituted 99.63%. Therefore, we postulate that these major elements could be measured first for rapid radiation exposure management of workers involved in decommissioning of nuclear power plants, even if all radioactive elements in concrete are not considered.

• Journal of Digital Convergence
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• v.15 no.5
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• pp.453-460
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• 2017

The purpose of this study was trying to figure out the effective employment guidance plan through employment preparation of graduating senior in department affiliated with physical education and recent situation. This study was compared to 2013 Graduates Occupational Mobility Survey(GOMS). Data were collected from 164 graduating seniors in the department affiliated with physical education from 5 institutions of a 4-year university located in Gyeonggi-do, Seoul, and ChungChong-do by convenience sampling. For the data analysis, a descriptive statistic, frequency analysis, and one-samples t-test were conducted. Graduating seniors participating in school employment programs had a lower rate but the average rate of participation in career & employment classes and vocational test was more than 50%. They were satisfied with university education and career support but employment program and welfare facilities are in need of improvement. Furthermore, graduating seniors have national and private certificates related to major. Finally, they have very low participation rates in youth employment policies of government. Based on the results, the effective job placement guideline for the department affiliated with physical education is needed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.1C
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• pp.120-130
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• 2009

In this paper, we propose a receiver structure for frequency synchronization in OFDMA (Orthogonal Frequency Division Multiple Access) system which is considered as 3GPP LTE(Long Term Evolution) downlink. In general, OFDMA frequency synchronization consists of two parts: coarse synchronization and fine synchronization. We consider P-SCH (Primary-Synchronization Channel) and CP (Cyclic Prefix) of OFDMA symbol for coarse synchronization and fine synchronization, respectively. The P-SCH signal has two remarkable disadvantages that it does not have sufficiently many sub-carriers and its differential correlation characteristic is not good due to ZC (Zadoff Chu) sequence-specific property. Hence, conventional frequency synchronization algorithms cannot obtain satisfactory performance gain. In this paper, we propose a modified differential correlation algorithm to improve performance of the coarse frequency synchronization. Also, we introduce an effective PLL (Phase Locked Loop) structure to guarantee stable performance of the fine frequency synchronization. Simulation results verify that the proposed algorithm has superior performance to the conventional algorithms and the 2nd-order PLL is effective to track the fine frequency offset even in high mobility.

• The Journal of the Acoustical Society of Korea
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• v.43 no.2
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• pp.214-224
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• 2024

Sonobuoys are disposable devices that utilize sound waves for information gathering, detecting engine noises, and capturing various acoustic characteristics. They play a crucial role in accurately detecting underwater targets, making them effective detection systems in anti-submarine warfare. Existing sonobuoy deployment methods in multistatic systems often rely on fixed patterns or heuristic-based rules, lacking efficiency in terms of the number of sonobuoys deployed and operational time due to the unpredictable mobility of the underwater targets. Thus, this paper proposes an optimal sonobuoy placement strategy for Unmanned Aerial Vehicles (UAVs) to overcome the limitations of conventional sonobuoy deployment methods. The proposed approach utilizes reinforcement learning in a simulation-based experimental environment that considers the movements of the underwater targets. The Unity ML-Agents framework is employed, and the Proximal Policy Optimization (PPO) algorithm is utilized for UAV learning in a virtual operational environment with real-time interactions. The reward function is designed to consider the number of sonobuoys deployed and the cost associated with sound sources and receivers, enabling effective learning. The proposed reinforcement learning-based deployment strategy compared to the conventional sonobuoy deployment methods in the same experimental environment demonstrates superior performance in terms of detection success rate, deployed sonobuoy count, and operational time.

• Journal of the Korean Applied Science and Technology
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• v.41 no.2
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• pp.413-423
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• 2024

Sixteen male college students were divided into two groups: a face-to-face group(n=8) and a real-time non-face-to-face exercise group(n=8), engaging in 30minute sessions twice a week for a duration of 8 weeks. Body composition and physical strength were measured as dependent variables before and after the home training period. For data analysis, a two-way ANOVA with repeated measures was conducted to evaluate the effects on body composition and physical strength, considering differences in exercise methods and measurement periods. Post hoc analysis using Bonferroni correction was applied. To compare the mean difference in change between groups, the pre-post difference was calculated, and an independent t-test was performed. The statistical significance level was set at p<.05. The results showed that 8 weeks of home training led to an increase in skeletal muscle mass and improvements in muscle strength, muscular endurance, and cardiorespiratory endurance in male college students, regardless of whether they participated in face-to-face or real-time non-face-to-face exercise. Moreover, there was no significant difference in exercise effectiveness between the face-to-face and real-time non-face-to-face exercise methods. Thus, these findings suggest that real-time non-face-to-face exercise can be as effective as face-to-face exercise in enhancing skeletal muscles and physical strength in male college students. Additionally, if a real-time non-face-to-face exercise program is validated for individuals with mobility issues or the elderly, it could serve as an effective alternative for those who face challenges in participating in face-to-face exercise sessions.