• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.4
• /
• pp.587-594
• /
• 2023

In this paper, we present the design and optimization process of an on-body microstrip patch antenna with a paired T-type defect for monitoring fracture recovery of human legs. This antenna is designed to be light, thin and compact despite the improvement of return loss and bandwidth performance by adjusting the size of the T-type defect. The structure around the applied human leg is structured as a 5-layer dielectric plane, and the complex dielectric constant of each layer is calculated using the 4-pole Cole-Cole model parameters. In a normal case without bone fracture, the return loss of the on-body antenna is -66.71dB at 4.0196GHz, and the return loss difference ΔS₁₁ is 37.95dB when the gallus layer have a length of 10.0mm, width of 1.0mme, and height of 2.0mm. A 3'rd degree polynomial is presented to predict the height of the gallus layer for the change in return loss, and the polynomial has a very high prediction suitability as RSS = 1.4751, R² = 0.9988246, P-value = 0.0001841.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.6
• /
• pp.277-286
• /
• 2019

The aim of this study was to investigate the effects of computer-based cognitive rehabilitation and traditional cognitive training on the working memory and executive function of patients with mild traumatic brain injury. The sample consisted of 20 patients with mild traumatic brain injury who had received rehabilitation treatment in a rehabilitation unit. The subjects were assigned to either the experimental (n = 10) or control group (n = 10). The experimental group received computer-based cognitive rehabilitation and traditional cognitive training for 60 minutes, whereas the control group received only traditional cognitive training for 60 minutes. Both the groups received their respective interventions for 60 minutes a day and 5 times per week across a period of 4 weeks. Working memory and executive function were assessed using the digit span test (forward and backward), visual memory 1 and 2 of the Motor-free Visual Perception Test-3, trail making test, and Stroop test (A and B) both before and after the intervention. The experimental group showed a significantly greater improvement in visual memory and performance on the Stroop test A than the control group. These findings suggest that computer-based cognitive rehabilitation and traditional cognitive training are more effective in promoting positive changes in the working memory and executive function of individuals with mild traumatic brain injury than traditional cognitive training.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.05a
• /
• pp.288-290
• /
• 2022

As part of the SOC digitization for smart water management and flood prevention, the government reported that automatic and remote control system for drainage facilities (180 billion won) to 57% of national rivers and established a real-time monitoring system (30 billion won). In addition, they were also planning to establish a smart dam safety management system (15 billion won) based on big data at 11 regions. Therefore, research is needed for smart water management and flood prevention system that can accurately calculate the flow rate through real-time flow rate measurement of rivers. In particular, the most important thing to improve the system implementation and accuracy is to ensure the accuracy of real-time flow rate measurements. To this end, radar sensors for measuring the flow rate of electromagnetic waves in the United States and Europe have been introduced and applied to the system in Korea, but demand for improvement of the system continues due to high price range and performance. Consequently, we would like to propose an improved flow rate measurement and flood forecast system by developing a radar sensor for measuring the electromagnetic surface current meter for real-time flow rate measurement.

• Journal of Service Research and Studies
• /
• v.12 no.3
• /
• pp.26-44
• /
• 2022

Job stress experienced during work has a positive effect on the organization, such as performance improvement, but if not properly managed, it can cause physical diseases such as digestive diseases and mental diseases such as depression and neurological diseases. If job stress persists for a long time, it causes emotional exhaustion and depression, which has a significant adverse effect on individuals and organizations, so proper management is essential. Therefore, in this study, a descriptive survey study was conducted using a self-report questionnaire method to find out the relationship between job stress, emotional exhaustion and depression of medical institution workers. As a result of the analysis, it was found that job stress of medical institution workers had a significant (+) effect on emotional exhaustion and depression, and emotional exhaustion of medical institution workers had a significant (+) effect on depression. Through this study, it was found that there was a significant relationship between job stress, emotional exhaustion, and depression of hospital employees, and that emotional exhaustion acts as a parameter in the relationship between job stress and depression. Considering that job stress of hospital employees causes adverse organizational effects, such as threatening workers' mental and physical health and causing deterioration in the quality of medical services, organizational efforts will be needed to relieve and properly manage job stress of hospital employees.

• Korean Chemical Engineering Research
• /
• v.61 no.1
• /
• pp.68-73
• /
• 2023

Smoke masks have attracted great interests and have been supplied widely for the improvement of the safety during fire evacuation. However, there is not sufficient research on the practical utility, certification status and easy-donning about commercial smoke masks, therefore it is difficult to determine the actual usefulness of the smoke masks. In this study, we conducted a survey on users' perceptions and experiences about the smoke masks, and investigated the status of certification of 54 commercial smoke masks. We also performed donning tests and examined degrees of discomfort for 4 types of the smoke masks. Although 22% of 235 respondents had experienced the smoke masks before the test, and 23% of the respondents did not know the smoke masks, 93% of the respondents expected that the smoke masks could protect users from fire smokes and toxic gases. It was found that 41% of the commercial smoke masks did not certify according to domestic or overseas performance standards. Most certification standards have not effectively regulated maximum wearing time for the smoke masks. Only ASTM E 2952 and KFIS 024 had specific standards for the maximum wearing time of 30 s. As a result of donning tests for 4 types of smoke masks, the wearing time of the hood-type mask and self-contained smoke mask exceeded 30 s, therefore these types of smoke masks might increase the required safe evacuation time. On the other hand, it was also found that short education about the donning could reduce the wearing time by 19% and numbers of improper wearing by 89%.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
• /
• v.16 no.2
• /
• pp.104-108
• /
• 2023

Because of recent expansion of the electric car market. it is highly growing that should be supplemented its performance and safely issue. The EMI problem due to the interlocking of electrical components that causes various safety problems such as fire in electric vehicles is emerging every time. We strive to achieve optimal charging efficiency by combining various technologies and reduce radioactive noise among the EMI noise of a weirless charging control module, one of the important parts of an electric vehicle was designed and tested. In order to analyze the EMI problems occurring in the wireless charging control module, the optimized wireless charging control module by applying the optimization design technology by learning the accumulated test data for critical factors by utilizing the Python-based script function in the Ansys simulation tool. It showed an EMI noise improvement effect of 25 dBu V/m compared to the charge control module. These results not only contribute to the development of a more stable and reliable weirless charging function in electric vehicles, but also increase the usability and efficiency of electric vehicles. This allows electric vehicles to be more usable and efficient, making them an environmentally friendly alternative.

• Composites Research
• /
• v.20 no.3
• /
• pp.8-16
• /
• 2007

Bending collapse of light-weight square tubes used for vehicle structure components is a dominant failure mode in oblique collision and rollover of vehicles. In this paper bending performances of aluminum-GFRP hybrid tube beams were evaluated in relation with bending deformation behavior and energy absorption characteristics. Aluminum/GFRP hybrid tube beams fabricated by inserting adhesive film between prepreg and metal layer were used in the bending test. Failure mechanisms of hybrid tubes under a bending load were experimentally investigated to analyze the bending performance as a function of ply orientation and composite layer thickness. Ultimate bending moments and energy absorption capacity of hybrid tube beams were obtained from the measured load-displacement corves. It was found that aluminum/GFRP hybrid tubes could be converted to rather stable collapse mode showing excellent energy absorption capacity in comparison to the pure aluminum tube beams. In particular, the hybrid tube beam with $[0^{\circ}/90^{\circ}]s$ composite layer showed a large improvement by about 78% in energy absorption capacity and by 29% in specific energy absorption.

• Journal of Digital Convergence
• /
• v.20 no.1
• /
• pp.191-202
• /
• 2022

The purpose of this study is to examine the effect of a 10-week body stability exercise program, which was conducted on 24 male football players. The result of the Visual Response Speed Test using BlazePod, showed a significant increase of the upper arms, left foot and right foot for 15 second in number of reactions and reaction time (p<0.001). As a result of evaluating whether or not 7 functional movements were improved in order to evaluate the functional movement screen, Hurdle Step (p=0.001) and Active Straight Leg Rise (p=0.022) movements were significantly improved. significantly improved. As a result of measuring the y-balance Test in order to evaluate the balance ability, composite score(p<0.001) of both sides was significantly improved. The result of evaluating vital capacity, which was conducted to evaluate mobility and muscle endurance, showed a significant improvement in Forced vital capacity(p<0.001) and Forced expiratory volume in 1.0(p=0.003). In conclusion, a 10-week BSE program intervention in high school period, which can most improve the technical fitness necessary for the game in power, agility, leg strength, leg stability, mobility, and muscle endurance, will improve overall technical fitness, prevent football players from being injured and enhance their performance.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.23 no.3
• /
• pp.145-151
• /
• 2023

3D-CNN is one of the deep learning techniques for learning time series data. Such three-dimensional learning can generate many parameters, so that high-performance machine learning is required or can have a large impact on the learning rate. When learning dynamic hand-gestures in spatiotemporal domain, it is necessary for the improvement of the efficiency of dynamic hand-gesture learning with 3D-CNN to find the optimal conditions of input video data by analyzing the learning accuracy according to the spatiotemporal change of input video data without structural change of the 3D-CNN model. First, the time ratio between dynamic hand-gesture actions is adjusted by setting the learning interval of image frames in the dynamic hand-gesture video data. Second, through 2D cross-correlation analysis between classes, similarity between image frames of input video data is measured and normalized to obtain an average value between frames and analyze learning accuracy. Based on this analysis, this work proposed two methods to effectively select input video data for 3D-CNN deep learning of dynamic hand-gestures. Experimental results showed that the learning interval of image data frames and the similarity of image frames between classes can affect the accuracy of the learning model.

• Journal of Korean Society for Quality Management
• /
• v.50 no.1
• /
• pp.169-181
• /
• 2022

Purpose: This paper addresses a case study of developing a flame retardant wood-plastic composites (WPC) by adding tannic acid to the existing synthetic wood. The optimal mixing ratios of six components are explored to minimize the burning time using two mixture designs. Methods: In the preliminary experiment, six components are considered to find important components and their ranges. Seven D-optimal mixture design points are generated. Two points are removed for the balance of plastic components to be maintained, and the remaining five points are augmented with two basic compositions. Four components are selected to be considered in the main experiment. In the main experiment, pellets are extruded at the eight mixture design points. In-house testing of burning time is executed three times. Specimens made of pellets from two promising flame retardant compositions are sent to the accredited laboratories and tested. Results: The test results are as follows: 1) The best composition (Wood flour, Tannic acid, PE, Lubricant) = (25, 41, 10, 2) (wt%) shows the burning time of 1 second, which is 9-fold improvement compared to the the burning time of 9 seconds from the existing composition (58, 0, 10, 2) (wt%). 2) The second best composition (41, 25, 10, 2) (wt%) results in the burning time of 2 seconds. This composition is inferior to the best composition in terms of the flame retardancy, but more economical since it needs less tannic acid which is 100-fold expensive than the wood flour. Conclusion: Flame retardant compositions are found by adding tannic acid to the existing WPC employing optimal mixture designs. This case study will be helpful to practitioners who try to develop new products with additional physical properties with as small number of experimental trials as possible. Future research direction includes exploring conditions which satisfy both performance level and cost limitation simultaneously.