• Journal of Satellite, Information and Communications
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• v.1 no.2
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• pp.89-94
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• 2006

ODFM(Orthogonal Frequency Division Multiplexing) technique is suitable for high speed data transfer both in wired/wireless channels, and is actively studied recently. Among them, WiBro based on IEEE 802.16 uses ODFM as its core technology, and is currently trying to expand market through commercialization. Therefore, if it's used for high speed moving object(KTX, airplane..etc) in near future, there is a possibility of ICI(inter-carrier interference) to occur due to DFS(Doppler Frequency Shift), a critical weak point of ODFM System. This study suggests 3 compensation techniques for Doppler effects in ODFM system operating through satellite, and confirms improved performance through constellation and BER curve.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.6
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• pp.43-49
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• 2022

FMCW(Frequency Modulated Continuous Wave) Radar is very useful for vehicle collision warning system and autonomous driving sensor. In this paper, the design and implementation of FMCW radar based on two chip MMIC developed as an autonomous driving sensor was described. Especially, generation of frame-based and chirp-based waveform generation and signal processing are mixed to have the strength of maximum detection speed and compensation of speed. This implemented system was analyzed for performance and commercialization potential through lab. test and driving test in K-city.

• Journal of Korean Physical Therapy Science
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• v.30 no.4
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• pp.1-8
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• 2023

Background: This study evaluates the usability of the Motion-Tracking Gait Assistive Walker (MTGAW) designed for elderly individuals and those with disabilities, identifying areas for improvement through interviews with physical and occupational therapists. Design: A survey study involves the usability test for MTGAW. Methods: Usability evaluations were conducted with 37 physical therapists and occupational therapists. The process included explanation, product usage, satisfaction surveys, and interviews. A satisfaction survey covering 19 items across safety, maneuverability, usability, and management areas was administered. Individual interviews identified areas for improvement. Results: Overall, high satisfaction was reported across the four areas, but interviews highlighted the need for improvements, such as addressing discomfort due to slow speed and enhancing safety measures to prevent rear-end falls. Adjusting the walker's height and width to suit the user's physique was also suggested. Conclusion: MTGAW enhances walking support and hand movement freedom but needs refinement in speed control, fall prevention, and customization based on the user physique. Future efforts should focus on developing an improved MTGAW, considering recommendations from physical therapy experts, and conducting studies to analyze its clinical effectiveness for commercialization.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.6
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• pp.129-135
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• 2016

There have been many types of development and commercialization efforts for superconducting power applications with the continuous development of High Temperature Superconducting (HTS) conductors. In particular, HTS power cables are going to be commercialized in real power grids. A cryogenic refrigeration system should be used to keep it below 77 K, and its required cooling capacity continuously increases as the unit length of the HTS power cable increases. Among the many kinds of cryogenic refrigerator, a reverse Brayton refrigerator that uses turbo expanders is a promising refrigerator due to its efficiency and reliability. Among the various components in refrigerators, the cryogenic turbo-expander is the most important part for increasing efficiency and assuring reliability. The design of a 300 W class turbo-expander is described in this paper prior to the development of a 10 kW class turbo expander, which is the required capability for the commercialization of a HTS power cable. The impeller shape and rotation speed are determined based on the cycle analysis. The Eigen frequency and harmonic analysis are conducted with gas bearings at cryogenic temperatures to determine the operational stability.

• Atmosphere
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• v.33 no.4
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• pp.413-422
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• 2023

Urban Air Mobility (UAM) is promising, sustainable and efficient air transportation in a metropolitan area. Korean government has recently announced operation demonstration plans as a step toward commercialization of UAM. However, there is lack of understanding on the potential impact of weather on UAM operation. We collected weather observations from Gimpo International Airport and 5 automatic weather stations (AWS) along UAM corridor of the Han-River to assess weather barriers such as low visibility, wind gust and wind shear. The results show the frequency of low visibility near the corridor fluctuated significantly from year to year depending on the concentration of fine particulate matter (PM_2.5) in Seoul. The frequency of high wind speed-shift calculated using 1-minute wind observations was increased not only during the spring season (March, April, and May) but also the beginning of rainy season (Jun). In addition, a chance of high wind shear from 1-minute wind observations varied by the stations, suggesting that the condition is largely affected by topography including a river and high-rise buildings. These basic weather properties suggest that there are substantial weather barriers to UAM operations along the Han-River Corridor, while they cannot properly surveil micro-scale weather conditions in detail such as wind gust and wind shear over the corridor. Thus, this study suggests that potential barriers related to adverse weather need to be evaluated, building high-density weather observations infrastructure prior to UAM demonstration and commercialization.

• Journal of Families and Better Life
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• v.19 no.3
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• pp.135-155
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• 2001

The purpose of this study was to investigate the general tendency of family/kin ritual transition and to find out related variables. For this purpose, 593 subjects of rural family were interviewed with questionnaires. The major results of the study were summarized as follows: 1. It was discovered that the characteristics of the ritual transition among the rural families is same as the urban families, i.e. westernization, commercialization, and socialization. But the speed of rural area was relatively slow. 2. In contemporary family/kin rites, traditional structure coexisted with external westernized aspects by the group who were elderly, lowly educated, lowly earned and Buddhist. 3. The family/kin rites were more significantly different depending on the age than gender, and the religion was the significant variable to the family/kin rites. So the family/kin ritual management education programs were needed.

• The Journal of Korea Robotics Society
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• v.9 no.4
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• pp.264-271
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• 2014

In this study, we have developed the humanoid joint modules which provide a variety of service while living with people in the future home life. The most important requirement is ensuring the safety for humans of the robot system for collaboration with people and providing physical service in dynamic changing environment. Therefore we should construct the mechanism and control system that each joint of the robot should response sensitively and rapidly to fulfill that. In this study, we have analyzed the characteristic of the joint which based on the target constituting the humanoid motion, developed the optimal actuator system which can be controlled based on each joint characteristic, and developed the control system which can control an multi-joint system at a high speed. In particular, in the design of the joint, we have defined back-drivability at the safety perspective and developed an actuator unit to maximize. Therefore we establish a foundation element technology for future commercialization of intelligent service robots.

• Journal of information and communication convergence engineering
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• v.2 no.4
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• pp.209-213
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• 2004

With the commercialization of CDMA 2000-1x late in 2000, a high-speed wireless Internet, based on a mobile communication networks, appeared in Korea. This will develop into the next-generation of mobile communications(4G) in the future and the new cell layout will be required the cellular configuration of 4G. We would need the legislation with respect to base-stations and to building the mobile communication networks, as well as the optimization of mobile communication systems. In this study, in order to provide 4G, I examined and analyzed that the current laws & regulations related to licensing and operating a mobile communication base-stations in KOREA.

• Vacuum Magazine
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• v.2 no.4
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• pp.39-46
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• 2015

After stepping into a new field of vacuum 30 years ago, our company has grown up steadily as a specialized vacuum industry, and now we can provide vacuum devices covering most of the pressure range. We are planning to put out high level dry pump like a multistage Roots pump on the market in the near future. Procedures of technology development for designing, fabricating, and testing the multistage Roots pump of 600 L/min class will be briefly reported. Core items of the technical development on the multistage Roots pump are as follows; elaborated profile design of 3-lobe rotors using an involute curve, optimization of rotor dimensions, especially for clearances and rotor width, considering the pumping speed, compression ratio and heat load, and establishment of a standardized test system. At present, the multistage Roots pump is about to come into commercialization.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.4
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• pp.27-32
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• 2007

Head-Up Display system makes it possible for the driver to be informed of important vehicle data such as vehicle speed, engine RPM or navigation data without taking the driver's eyes off the road. Long focal length optics, LCD with bright illumination, image generator and vehicle interface controllers are key parts of head-up display system. All these parts have been designed, developed and applied to the test vehicle. Virtual images are located about 2m ahead of the driver's eye by projecting it onto the windshield just below the driver's line of sight. Developed head-up display system shows satisfactory results for future commercialization.