• The Transactions of the Korean Institute of Electrical Engineers D
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• v.52 no.2
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• pp.85-92
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• 2003

In this paper, we propose a method to evaluate performances of mobile personal robots. A set of performance measures is proposed and the corresponding evaluation methods are developed. Different from industrial manipulators, personal robots need to be evaluated with its mobility, navigation, task and intelligent performance in environments where human beings exist. The proposed performance measures are composed of measures for mobility including vibration, repeatability, path accuracy and so on, as well as measures for navigation performance including wall following, overcoming doorsill, obstacle avoidance and localization. But task and intelligent behavior performances such as cleaning capability and high-level decision-making are not considered in this paper. To measure the proposed performances through a series of tests, we designed a test environment and developed measurement systems including a 3D Laser tracking system, a vision monitoring system and a vibration measurement system. We measured the proposed performances with a mobile robot to show the result as an example. The developed systems, which are installed at Korea Agency for Technology and Standards, are going to be used for many robot companies in Korea.

• Textile Coloration and Finishing
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• v.33 no.4
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• pp.288-301
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• 2021

The purpose of this study was to verify the degree of visibility of FOLED (fiber optic light-emitting diode) materials applied to safety-enhancing clothes of micro-mobility users during the day and night by conducting an empirical test targeting 50 people in their teens, 20's, 30's, 40's, and 50's or older. First, the results of the visibility test at 10 m-intervals from 10 to 70 m based on the clothes sample showed that the light detection of FOLED material was very good without daytime or night-time distinction. Second, the results of directional sign detection of FOLED were confirmed to be very high without any daytime or night. Third, the results of identifying a pictogram design showed that the distance was shorter than that of light detection or directional indication. However, the FOLED pictogram design could be confirmed at a distance of 50 m or less. Therefore, if a clothes product using FOLED material is worn and micro-mobility is used, the experimental results indicate that safety will be sufficiently secured due to the excellent visibility.

• Physical Therapy Rehabilitation Science
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• v.12 no.3
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• pp.300-309
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• 2023

Objective: The purpose of this study was to investigate the effects of gastrocnemius neuromuscular electrical stimulation training on ankle mobility and gait in patients with stroke. Design: A randomized controlled trial. Methods: 31 patients with stroke were selected and classified into an experimental group (n=16) and a control group (n=15). Both groups were assessed for ankle mobility using the Knee to Wall Test and gait parameters using G-walk before and after the intervention. The intervention was applied five times a week for four weeks. The experimental group performed gastrocnemius neuromuscular electrical stimulation followed by ankle control exercises, while the control group only applied NMES to the tibialis anterior muscle of the paretic side for 30 min per session five times a week for 4 weeks. Results: Experimental group showed significant improvements in Knee to wall test. and lumbar flexibility after the intervention. both group showed significant improvements in gait parameters after the intervention. However, when comparing between the two groups, the experimental group showed a more significant effect than the control group. Conclusions: Gastrocnemius neuromuscular electrical stimulation training can be considered an effective approach to improve ankle mobility and gait ability in patients with stroke.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.382-389
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• 2007

In this paper we report the development of mobility test bed, the realization of basic protocol that supports L3 mobility and the measurement of performance parameters that can affect handover performance. Previously proposed mobility management system, BBM (Break Before Make) method such as MIPV6 and Fast MIPV6, uses one interface in wireless network. In this method, to connect to new AP, it first disconnects existing AP and tries to connect to new AP. This can cause packet loss for the traffic vulnerable to delay such as VoIP. To provide seamless handover between different wireless networks, we propose MBB (Make Before Break) handover method having two network interfaces. Comparative study of previous method and proposed method on mobility and handover was conducted under simulated real environment on the test bed. Almost no packet loss was found with newly proposed method. In conclusion, it is shown that mobility protocol with proposed handover method can be applied to the application services sensitive to delay and packet loss.

• Journal of Advanced Navigation Technology
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• v.22 no.5
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• pp.391-399
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• 2018

V2X communication is a technology in which a vehicle exchanges information with various entities such as other vehicles, infrastructure, networks, pedestrians, etc. through a wired or wireless network. Recently, V2X communication technology has been steadily developed and recently it has played an important role in autonomous cooperation driving technology combined with autonomous vehicle technology. Autonomous vehicles can utilize the external information received via V2X communication to extend the recognition range of existing sensors and to support more safe and natural autonomous driving. In order to operate these autonomous cooperative vehicles on public roads, the security and reliability of autonomous V2X communication should be verified in advance. In this paper, we present test scenarios and test procedures of secure V2X communication for cooperative automated driving and present verification results.

• Journal of the Korean Society of Physical Medicine
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• v.17 no.4
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• pp.93-101
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• 2022

PURPOSE: This study sought to investigate the effects of treadmill gait training combined with a thoracic mobility exercise on gait and balance in patients with stroke. METHODS: In this single-blinded, randomized, controlled, comparative study, a total of 20 patients at a rehabilitation hospital who had suffered a hemiplegic stroke were randomly assigned to the experimental group (treadmill gait training combined with a thoracic mobility exercise, n = 11) or control group (treadmill gait training without the thoracic mobility exercise, n = 9). All the participants underwent comprehensive rehabilitation therapy (5 × /week for 4 weeks). Additionally, the experimental group underwent 20 min of treadmill gait training combined with 10 min of a thoracic mobility exercise (3 × / week for 4 weeks) and the control group underwent the former but not the latter. Gait and balance were measured before and after the 4-week training. RESULTS: Significant improvements were observed in the 10-m walking test (10 MWT), timed up-and-go (TUG) test, center of pressure (COP) velocity, and COP length in the experimental group (p < .05). This group also showed a larger decrease in the 10 MWT and COP velocity than the control group (10 MWT, -3.02 sec vs. -1.68 sec, p < .05; COP velocity, -.07 mm/sec vs. .08 mm/sec, p < .05). CONCLUSION: Treadmill gait training, combined with the thoracic mobility exercise, could be effective in improving the gait and balance of stroke patients. It could also be more effective in improving walking speed and static balance than the treadmill gait training alone.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.29 no.2
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• pp.1-10
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• 2023

Background: The purpose of this study was to evaluate the pain, static balance, and dynamic balance abilities of women with chronic low back pain by performing thoracic and hip joint mobility exercises and lumbar stability exercises. Methods: The subjects of this study were 20 adult women with low back pain who lived in C city for more than 12 weeks. The experimental group performed the thoracic and hip mobility exercises with lumbar stability exercises and the control group performed the lumbar stability exercise with general exercise program. Both groups participated in the exercise program three times a week for six weeks, from December 20, 2022 to March 7, 2023. The balance ability were measured using BT4, and pain was measured using visual analog scale (VAS). The collected data were analyzed by independent sample t-test and paired t-test using SPSS version 23.0 program. Results: After 6 weeks of intervention, there was a significant change in VAS between the experimental group and the control group, and there was no difference between the two groups (p>.05). In the case of balance ability, there was a no significant increase in the experimental group (p>.05). Conclusion: Thoracic and hip joint mobility exercises and lumbar stability exercises for adult female patients with chronic low back pain may be partially effective in static balance and dynamic balance.

• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.179-189
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• 1997

Teeth mobility is an important part of a periodontal examination, because it represents a function of the persisting height of the alveolar bone and the width of the periodontal ligament. The purpose of this study was to evaluate clinical difference in teeth mobility after treatment with the modified Widman flap and the undisplaced flap in humans. Twenty males with moderate periodontal disease were selected. The severity of periodontal disease was evaluated with sulcular bleeding index, pocket depth and attachment level and tooth mobility was measured with Periotest(Siemens Co., Germany) at the initial examination, 1, 2, 4, 6, 8 and 12 weeks following the modified Widman flap and the undisplaced flap operation using the split-mouth technique. The relation of mobility to clinical parameters was statistically analyzed by multiple regression and the change of teeth mobility according to healing process by independent t-test using SPSS program. The results were as follows: 1. There was a strong relationship between the Periotest value(PTV) and attachment level. 2. The change of teeth mobility in both flap procedures was increased significantly at 1 week post-op. and was decreased to preoperative level at 4 weeks post-op, in modified Widman flap and at 6 weeks post-op. in undisplaced flap. 3. The change of teeth mobility in premolar teeth group in undisplaced flap compared to modified Widman flap was generally increased but these changes were not statistically significant. The changes of teeth mobility in molar teeth group in undisplaced flap was increased significantly at 2 weeks post-op.. 4. The change of teeth mobility following undisplaced flap was increased significantly compared to that of modified Widman flap at 2 weeks post-op.

• The Journal of the Korea Contents Association
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• v.12 no.8
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• pp.264-273
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• 2012

The purpose of this study was to determine the test-retest reliability and the concurrent validity between tinetti mobility test (TMT), berg balance scale (BBS) and space balance 3D which is one of the computerized measurement and visual feedback balance assessment system in subacute stroke patients. Twenty three ambulatory acute stroke subjects were measured the TMT, BBS and space balance 3D. The test-retest reliability(intra-class correlation coefficient: ICC) indicated that the static and dynamic balance in space balance 3D considered moderate reliability and TMT, BBS were good reliability. In case of concurrent validity, there were moderate validity (p<.01) between static balance test with space balance 3D and each TMT, BBS. But there were only poor validity (p<.05) between center to forward-left, center to backward-left phase in dynamic balance test with space balance 3D and each TMT, BBS. These findings suggest that in subacute stroke patients the test-retest reliability and concurrent validity using the space balance 3D and TMT were valuable in balance test but there was limitation to evaluate dynamic balance test.

• Journal of Positioning, Navigation, and Timing
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• v.4 no.1
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• pp.9-16
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• 2015

The applications of Global Navigation Satellite System (GNSS) receivers are becoming wider in various commercial and military systems including even small weapon systems such as artillery shells. The precision-guided munitions such as Small Diameter Bomb (SDB) of United States can be used for pinpoint strike by acquiring and tracking GNSS signals in high mobility situation. In this paper, a small GNSS receiver with embedded interference suppression capability working under high dynamic stress is developed which is applicable to the various weapon systems and can be used in other several harsh environments. It applies a kind of matched filter and multiple correlator schemes for fast signal acquisition and tracking of even weak signals and frequency domain signal processing method to eliminate the narrowband interference. To evaluate the performance of the developed GNSS receiver, the test scenario of high mobility and interference environment with the GNSS simulator and signal generator is devised. Then, the signal acquisition time, navigation accuracy, sensitivity, and interference suppression performances under high dynamic operation are evaluated. And the comparison test with the commercial GNSS receiver which has high sensitivity is made under the same test condition.