• Journal of the Semiconductor & Display Technology
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• v.16 no.4
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• pp.59-62
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• 2017

In this paper, atmospheric pressure plasma treatment was proposed for high performance indium gallium zinc oxide thin film transistor (IGZO TFT). RF Ar plasma treatment is performed at room temperature under atmospheric pressure as a simple and cost effective channel surface treatment method. The experimental results show that field effect mobility can be enhanced by $2.51cm^2/V{\cdot}s$ from $1.69cm^2/V{\cdot}s$ to $4.20cm^2/V{\cdot}s$ compared with a conventional device without plasma treatment. From X-ray photoelectron spectroscopy (XPS) analysis, the increase of oxygen vacancies and decrease of metal-oxide bonding are observed, which suggests that the suggested atmospheric Ar plasma treatment is a cost-effective useful process method to control the IGZO TFT performance.

• The Journal of Korean Physical Therapy
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• v.33 no.2
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• pp.114-121
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• 2021

Purpose: This study examined the effects of therapeutic massage (TMP) and home exercise program (HEP) on pain, range of motion (ROM), depression, and quality of life (QOL) after arthroscopic rotator cuff repair in middle-aged women. Methods: Nineteen middle-aged women who underwent arthroscopic rotator cuff repair were enrolled in the study. All subjects were assigned randomly to the experimental group (n=9) or the control group (n=10). The subjects in both groups performed HEP for 30 minutes, three times per day, for eight weeks. The subjects in the experimental group also performed HEP, with TMP being performed for 30 minutes, 16 sessions for eight weeks. All subjects were evaluated with a visual analogue scale (VAS), shoulder ROM, self-rating depression scale (SDS), and Korean brief version of WHO quality of life scale (WHOQOL-BREF). A paired t-test was performed to test the significant differences between before and after the intervention. An independent t-test was conducted to test the significant differences between the groups. Results: Following the intervention, both groups showed significant differences than before the intervention in the VAS, shoulder ROM, SDS, and WHOQOL-BREF (p<0.05). There were significant differences in the ROM of shoulder flexion, SDS, and WHOQOL-BREF between the groups (p<0.05). Conclusion: These findings suggest that intensive TMP is an effective method for improving shoulder flexion mobility, depressive symptom, and QOL in middle-aged women after arthroscopic rotator cuff repair.

• Journal of IKEEE
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• v.24 no.4
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• pp.1017-1021
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• 2020

In the V2X communications, each vehicle periodically broadcasts a message, called a beacon, so that its neighbor vehicles can accurately predict the near-future positions of the sending vehicle. In particular, the mobility-adaptive beacon broadcast (MAB2) scheme keeps the tracking error of a sending vehicle below a fixed threshold within a few consecutive beacon losses. In this paper, we present a random-early beacon broadcast (REB2) scheme that addresses the beacon aging problem of the MAB2 scheme. The simulation results show that, for a neighbor vehicle within 100 m distance, the tracking failure probability of REB2 scheme can be reduced to less than 1/10 of that of MAB2 scheme.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.1
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• pp.74-81
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• 2021

UAM(Urban Air Mobility) systems have evolved in the form of helicopters in the 1960~1970s, tiltrotors in the 1980s, small aircraft transportation systems in the 2000s, and electric-powered Vertical Take-Off and Landing (eVTOL) in the 2010s; accordingly, the early heliport has evolved to its current form of a Vertiport. Vertical Takeoff and Landing Sites, Vertiports, are important factors for the successful introduction of UAM, along with the resolution of air traffic control (ATC), air security, and noise problems. However, there are no domestic or international installation standards and guidelines yet. Therefore, in this study, installation standards were prepared by referring to domestic and international case studies, ICAO standards, and MIT research papers. The study proposes to establish standards for Final Approach and Takeoff Area (FATO) as 1.5D, 1D for Touchdown and Lift-Off Area (TLOF), and 1.5D for Safety Area (SA). It also proposes to add "UAM Vertiport Installation Standards" to the 「Act on the Promotion and Foundation of Drone Utilization, Drone Act」.

• Physical Therapy Rehabilitation Science
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• v.11 no.3
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• pp.370-375
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• 2022

Objective: The purpose of this study was to compare the hip joint muscle strength of patients with chronic back pain with lumbar instability and normal subjects. Design: A case control study. Methods: Five types of lumbar instability test were conducted on forty young women with chronic low back pain for more than six months, and those who had 3 or more positive tests were selected as subjects. To select chronic back pain patients with lumbar instability group, aberrant movement patterns during lumbar flexion test (FMT), prone instability test (PIT), posterior-anterior mobility test (PAT), passive lumbar extension test (PLE), and pressure bio-feedback (PBF) were applied. In addition, a digital muscle strength meter was used to measure the hip flexor, extensor, adductor, and abductor muscles of chronic low back pain patients with lumbar instability group (n=20) and normal subject group (n=20). Results: As a result of comparing the hip joint muscle strength between the chronic back pain patient group with lumbar instability and the normal group, there were significant differences in the hip extensor, abductor, and adductor muscles (p<0.05). Conclusions: Patients of chronic back pain with lumbar instability were found to have weak hip joint muscle strength. Therefore, this study suggest that include hip joint strength exercise for functional recovery of chronic back pain patients.

• The Transactions of the Korean Institute of Power Electronics
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• v.27 no.2
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• pp.165-173
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• 2022

The electrification trend of mobility increases every year due to the development of power semiconductor and battery technology. Accordingly, the development and distribution of fast chargers for electric vehicles (EVs) are in demand. In this study, we propose a design and implementation method of an LLC converter for fast chargers. Two 15 kW LLC converters are configured in parallel to have 30 kW rated output power, and the control algorithm and driving sequence are designed accordingly and verified. In addition, the improved power conversion efficiency is confirmed through zero-voltage switching (ZVS) of the LLC converter and reduction of turn-off loss through snubber capacitors. The implemented 30 kW LLC converters show a wide output voltage range of 200-950 V. Experiments applying various load conditions verify the converter performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.463-473
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• 2023

In recent years, the transparent amorphous oxide thin film transistor represented by indium-gallium-zinc-oxide (IGZO) has become the first choice of the next generation of integrated circuit control components. This article contributes an overview of IGZO thin-film transistors (TFTs), including their fundamental principles and recent advancements. The paper outlines various TFT structures and places emphasis on the fabrication process of the active layer. The result showed that the size of the active layer including the length-to-width ratio and the width could have a significant effect on the mobility. And the process of TFT could influence the crystal structure of IGZO thin film. Furthermore, the article presents an overview of recent applications of IGZO TFTs, such as their use in display drivers and TFT memories. At last, the future development of IGZO TFT is forecasted in this paper.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.285-292
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• 2023

Small-scale ground mobile robots can access confined spaces where people or larger robots are unable. As the scale of the robot decreases, the relative size of the environment increases; therefore, maintaining the mobility of the small-scale robot is required. However, small-scale robots have limitations in using a large number of high-performance actuators, powerful computational devices, and a power source. Insects can effectively navigate various terrains in nature with their legged motion. Discrete contact with the ground and the foot enables creatures to traverse irregular surfaces. Inspired by the leg motion of the insect, researchers have developed small-scale robots and they implemented swing and lifting motions of the leg by designing leg linkages that can be adapted to small-scale robots. In this paper, we propose a leg linkage design for insect-inspired small-scale ground mobile robots. To use minimal actuation and reduce the control complexity, we designed a 1-DOF 3-dimensional leg linkage that can generate a proper leg trajectory using one continuous rotational input. We analyzed the kinematics of the proposed leg linkage to investigate the effect of link parameters on the foot trajectory.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.769-775
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• 2022

Global efforts to reduce carbon emissions have focused attention on the development of hydrogen energy and the development of various hydrogen mobility requires mobile hydrogen charging stations. In this study, the flow characteristics of the flow control hydrogen valve for mobile hydrogen charging equipment were studied according to the temperature change of hydrogen gas. The inlet pressure was 100 MPa, the outlet pressure to 70 MPa, and temperature condition was set -40℃ to 85℃. As a result, the difference in the valve flow coefficient, which determines the capacity of the valve, showed a difference within 5% depending on the temperature.

• Clinical Pain
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• v.18 no.2
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• pp.121-125
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• 2019

Arthritis of hip joints deteriorates the quality of life in ankylosing spondylitis (AS) patients. Secondary to the articular inflammatory process, the shortened hip-girdle muscles contribute to the decreased joint mobility which may lead to the functional impairment. As the limitation of range of motion (ROM) usually progress slowly, clinicians regard it as a chronic condition and prescribe long-term therapy. However, by short-term intensive multimodal treatment, a 20-year-old man diagnosed as AS with severely limited hip joint ROM who relied on crutches doubled the joint angle and could walk independently only within 2 weeks. The combination included intra-articular steroid injection, electrical twitch obtaining intramuscular stimulation, extracorporeal shock wave therapy, heat, manual therapy, and stretching exercises. The management focused on the relaxation of hip-girdle muscles as well as the direct control of intra-articular inflammation. Hereby, we emphasize the effectiveness of intensive multimodal treatment in improving the function even within a short period.