• The Journal of Korean Physical Therapy
• /
• v.24 no.4
• /
• pp.268-275
• /
• 2012

Purpose: This study is to identify how eye movement influences the static balance and fall efficacy of the elderly who have experienced fall-related injuries. Methods: Thirty nine elderly who scored 24 points in the Korean mini mental state examination, were able to walk, and had no specific disease, were selected as the research subjects among elderly who have experienced fall-related injury more than once in the past year. Thus, 20 for the experimental group, and 19 for the control group were selected as subjects. The experiment was conducted for 6 weeks, including periods of evaluation before and after intervention. Results: The results with respect to the dependent variables are as follows: Substitute sample t-testing showed significant differences between each group in eye movement to check difference in balance performance and fall efficacy. When independent sample t-tests were conducted to compare static balancing performance and fall efficacy between the two groups after intervention, they showed significant differences in statistical terms (p<0.05). Conclusion: From the above results of the study, it was found that the application of eye movement combined with diverse fall prevention programs is effective, when enhancing static balance performance power and improving fall efficacy.

• Electronics and Telecommunications Trends
• /
• v.32 no.6
• /
• pp.105-115
• /
• 2017

This paper describes a project - based quality management model that identifies development technologies and codes while at the same time verifying the ability to implement processes that are essential in R & D projects. In order to verify the process implemented in the R & D project implementation, there are review, checking points, and evaluating methods the process performance levels for five processes such as defining requirements which is the beginning stage of system development, testing process which is the completion stage of system development, and project management and peer review process for project management and support in the proposed project-based quality management model. For development technology and code validation, the model included the documented test cases for each requirement by the developer in the requirements definition stage, debugging and testing in the design and implementation stages, static analysis and open source licence verification procedure, and system environment. After applying the model in SW development R&D project for evaluating the process performance, and verifying the development technology and the code, the developers responded that the improvement in the development technique and the code, and upgrade of process performance level for project are more than 10%.

• Journal of Space Technology and Applications
• /
• v.3 no.4
• /
• pp.333-341
• /
• 2023

This study aims to develop technology for testing and verifying the space radiation environment of miniature space components using the facilities of the domestic 100 MeV proton accelerator and the Space Component Test Facility at the Space Testing Center. As advancements in space development progress, high-performance satellites increasingly rely on densely integrated circuits, particularly in core components components like memory. The application of semiconductor components in essential devices such as solar panels, optical sensors, and opto-electronics is also on the rise. To apply these technologies in space, it is imperative to undergo space environment testing, with the most critical aspect being the evaluation and testing of space components in high-energy radiation environments. Therefore, the Space Testing Center at the Korea testing laboratory has developed a radiation testing device for memory components and conducted radiation impact assessment tests using it. The investigation was carried out using 100 MeV protons at a low flux level achievable at the Gyeongju Proton Accelerator. Through these tests, single event upsets observed in memory semiconductor components were confirmed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2013.04a
• /
• pp.347-352
• /
• 2013

Seoul National University Flap (SNUF) blade is a small-scaled rotor blade incorporating a small trailing-edge flap control surface driven by piezoelectric actuators at higher harmonics for vibration attenuation. Initially, the blade was designed using two-dimensional cross-section analysis and a geometrically exact one-dimensional beam analysis, and material configuration was finalized. Flap deflection angle of ${\pm}45^{\circ}$ was established as the criterion for better vibration reduction performance based on an earlier simulation. Flap linkage mechanism design is carried out and static bench tests are conducted to verify the flap actuation mechanism performance. Different versions of test beds are developed and tested with the flap and chosen APA 200M piezoelectric actuators. Through significant improvements, a maximum deflection of ${\pm}3.7^{\circ}$ was achieved. High frequency experiments are conducted to evaluate the performance and transfer function of the test bed is determined experimentally. As the static tests are almost completed, rotor power required for testing the blade in whirl tower (centrifugal environment) is calculated and further preparations are under way.

• Journal of the Korean Society for Railway
• /
• v.8 no.4
• /
• pp.342-347
• /
• 2005

The Korean High-Speed Train(HSR 350x) had been developed by through 'G7-R&D project' in 1996-2002, and has been testing and evaluating it's reliability on the high-speed line until now. A number of core equipments designed and developed by using domestic technologies were boarded on the HSR 350x. In order to verify the performance of HSR 350x and core equipments such as traction system, brake system and pantograph, sophisticated testing and evaluating procedures should be considered and applied. In this paper, the tested and analysed results about the dynamic characteristics of HSR 350x pantograph are introduced in a view point of the mean contact force and it's variation trend, criterion of current collection, and up-lifting of contact wire when the MSR 350x running up to 350 km/h. Through the test and evaluation, we verified that HSR 350x pantograph had an excellent current collection performance and good dynamic characteristics as it had been designed.

• Structural Engineering and Mechanics
• /
• v.64 no.3
• /
• pp.301-310
• /
• 2017

For further development of passive control systems to dissipate larger seismic energy and prevent the structures from earthquake losses, this paper proposes an innovative two-level control system to improve behavior of chevron braced steel frames. Combining two Knee Braces, KB, and a Vertical Link Beam, VLB, in a chevron braced frame, this system can reliably sustain main shock and aftershocks in steel structures. The performance of this two-level system is examined through a finite element analysis and quasi-static cyclic loading test. The cyclic performances of VLB and KBs alone in chevron braced frames are compared with that of the presented two-level control system. The results show appropriate performance of the proposed system in terms of ductility and energy dissipation in two different excitation levels. The maximum load capacity of the presented system is about 30% and 17% higher than those of the chevron braced frames with KB and VLB alone, respectively. In addition, the maximum energy dissipation of the proposed system is about 78% and 150% higher than those of chevron braced frames with VLB and KB respectively under two separate levels of lateral forces caused by different probable seismic excitations. Finally, high performance under different earthquake levels with competitive cost and quick installation work for the control system can be found as main advantages of the presented system.

• Journal of international Conference on Electrical Machines and Systems
• /
• v.1 no.4
• /
• pp.509-516
• /
• 2012

This paper describes the testing and experimental characterization of a linear permanent magnet actuator, which is designed and developed for active vehicle suspension, under both static and dynamic conditions. Since the active suspension unit operates over a wide force-velocity range with varying duty ratios, it is essential to establish an effective thermal model which can be used for assessing temperature rise of the actuator under various operating conditions. The temperature rise of the actuator is measured and the results are compared with the prediction by the derived transient thermal model. It is shown that the measured actuator parameters and characteristics are closed to their predicted values. The linear actuator is controlled by a dSPACE system via a three phase inverter and its velocity tracking performance is presented.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.29 no.6 s.237
• /
• pp.755-762
• /
• 2005

To evaluate the aerodynamic efficiency of TR-S2 configuration designed by SUDC, wind tunnel tests of $40\%$ scaled model were done in KARI LSWT. The aerodynamic characteristics of plain and Semi-Slotted Flaperon were compared, and vortex generators were installed to improve flow pattern along the wing surface. Effects of the control surface such as elevator, rudder, aileron, and incidence angle of horizontal tail are measured for various testing conditions. Test results showed that Semi-Slotted Flaperon produced more favorable lift, lift/drag, and stall margins and application of vortex generator would be best choice to enhance wing performance. Longitudinal, lateral and directional characteristics of TR-S2 were found to be stable for the pitch and yaw motions.

• Proceedings of the Korea Concrete Institute Conference
• /
• 1996.04a
• /
• pp.348-353
• /
• 1996

This study addresses the evaluation of the durability of reinforced concrete marine structures subjected to fatigue loading. The laboratory investigation was carried out on full and half size reinforced concrete specimens with three different water cement ratios (0.3, 0.4, and 0.56), static and fatigue loading conditions, and epoxy-coated and regular black steel reinforcements. The marine tidal zone was simulated by alternate filling and draining of the tank (wet and dry cycled), and a galvanostatic corrosion technique to accelerate corrosion of reinforcement was used. Half-cell potentials and changes of crack width were measured periodically during the exposure and followed by ultimate strength testing. The significant findings include adverse effect of fatigue loading, existence of an explicit size effect, poor performance of epoxy coated steel, and negative effect of increasing water/cement ratio.

• Journal of Biomedical Engineering Research
• /
• v.33 no.2
• /
• pp.89-97
• /
• 2012

The purpose of this study is to develop the guideline of the physicochemical and mechanical properties evaluation for silicone gel filled breast implants. First of all, the use and development status for silicone gel filled breast implants were investigated, and then, standard and criteria about performance evaluation established by the international organizations such as ASTM, FDA guidance and ISO were examined. To evaluate the mechanical properties, data research and testing for breaking strength, elongation, tensile set, joint intensity, silicone gel cohesion, weight loss from heating, static rupture resistance, impact resistance test, fatigue test, and gel bleed were performed. On the other hand, to evaluate the physicochemical properties, volatile matter, extent of cross linking, heavy metals, and extractable were analyzed. In this study, results for general function, mechanical properties and physicochemical properties were examined and reviewed for the accordance with international standard, and objective and standardized guideline was provided.