• Journal of Biosystems Engineering
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• v.29 no.2
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• pp.101-108
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• 2004

The objectives of this study were to determine the natural frequency of a walking-type cultivator's handle using a modal analysis, to determine whether or not the handle resonates with forcing frequency induced by its engine, and to determine a method to reduce the handle vibration using a technique of the operational deflection shapes(ODS). Results of the study are as follows: The natural frequencies of the handle up to third harmonics were found to be 20.4, 22.5 and 92.1 Hz in the vertical direction and 14.9, 93, and 132 Hz in the horizontal direction. It was found that the handle does not resonate with the forcing frequency of the engine, which is 52 Hz. The operational deflection shape analysis revealed the deflected shapes of the handle in the vertical and horizontal directions and suggested that the handle vibration can be reduced by adding some mass to the place where the largest deflection occurs. Attaching of 1.1 kg mass adjacent to the largely deflected area resulted in reductions of vibration from 9.45 to 8.03 m/s$^2$ in x-axis direction from 3.89 to 3.16 m/s$^2$ in y-axis direction and from 7.89 to 3.09 m/s$^2$ in z-axis direction, which are respectively 15, 19 and 61% reductions. The total vibration level was reduced by 29%, indicating that mass-adding method by the ODS is very effective for reducing the handle vibrations of the cultivators.

• Journal of Preventive Medicine and Public Health
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• v.47 no.2
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• pp.113-123
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• 2014

Objectives: Several previous studies have found that healthy behaviors substantially reduce non-communicable disease incidence and mortality. The present study was performed to estimate the prevalence of four modifiable healthy behaviors and a healthy lifestyle among Korean adults according to socio-demographic and regional factors. Methods: We analyzed data from 199 400 Korean adults aged 19 years and older who participated in the 2010 Korean Community Health Survey. We defined a healthy lifestyle as a combination of four modifiable healthy behaviors: non-smoking, moderate alcohol consumption, regular walking, and a healthy weight. We calculated the prevalence rates and odds ratios of each healthy behavior and healthy lifestyle according to socio-demographic and regional characteristics. Results: The prevalence rates were as follows: non-smoking, 75.0% (53.7% in men, 96.6% in women); moderate alcohol consumption, 88.2% (79.7% in men, 96.9% in women); regular walking, 45.0% (46.2% in men, 43.8% in women); healthy weight, 77.4% (71.3% in men, 73.6% in women); and a healthy lifestyle, 25.5% (16.4% in men, 34.6% in women). The characteristics associated with a low prevalence of healthy lifestyle were male gender, younger age (19 to 44 years of age), low educational attainment, married, living in a rural area, living in the Chungcheong, Youngnam, or Gwangwon-Jeju region, and poorer self-rated health. Conclusions: Further research should be implemented to explore the explainable factors of disparities for socio-demographic and regional characteristics to engage in the healthy lifestyle among adults.

• Journal of Environmental Science International
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• v.19 no.4
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• pp.427-436
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• 2010

In this study this author made research and analysis on physical status and characteristics of community parks in Ik-san provinces and also depending on its potential resources such parks were classified into constructed parks and unconstructed parks and status of use of such parks and level of satisfaction were studied. Through this paper this author strived to provide basic data required for forming green track of land for the parks. Required time for visiting community parks either constructed or unconstructed type was within 40 minutes or less. However constructed parks appeared to be more convenient for access in comparison with natural unconstructed parks. Mostly they were used by residents in neighboring community and also residents in the area around it were found as using it frequently. At the time of using community parks either constructed or unconstructed types means of access were mostly by walking or by riding bicycles. Thus considering large number of users of such parks are from neighboring community it appeared that parks with its simplicity and convenience in terms of distance and with rich nature were preferred by users rather than large scale parks at distance. In terms of time frame of use and motivation of visit constructed parks were used mainly for exercise and relaxation in the morning at parks and its facilities whereas un constructed parks were mostly used in the afternoon for for walking and chatting and rest under with time to spare at shadows of its trees. Time spent at parks were composed mostly of rest and walking more frequently than exercise and leisure activity thus it was different from motivation for visiting parks. As for evaluation of use of parks natural elements, unique environment, trees and lawns featured highly in unconstructed parks in comparison with constructed parks. Thus it seemed visitors are more conscious of forest and landscape in a form of unchanged nature. Thus for community parks first consideration should be heightening accessibility in view of primary concern for convenience by users rather than facilities or environmental conditions.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.2
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• pp.129-136
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• 2017

PURPOSE: The purpose of this study was to compare the gait of elderly patients with and without dementia to investigate the possibility of an ambulation assessment test as a diagnostic tool for dementia. METHODS: A total of 96 subjects were included with 60 participants without dementia (control group) and 36 patients with dementia (dementia group). To compare the walking ability of the two groups, a 4-m walking test (4MWT) and Groningen Meander Walking Test (GMWT) were conducted. The GMWT is graded by amount of time in seconds and by number of oversteps outside the track. Mann-Whitney U test was used to compare the gait between the groups and the area under the curve (AUC) with Received Operating Characteristic (ROC) curve was analyzed. Statistical significance was considered at a p<.05, with a 95% confidence interval. RESULTS: There were statistically significant differences (p<.05) between the dementia group and the control group for the 4MWT, GMWTSEC, and GMWTSTEP scores. The AUC was .95 for 4MWT, .92 for GMWTSEC, and .96 for GMWTSTEP with the 95% confidence interval. The cut-off values of the ROC curve were 1.03m/s for 4MWT, 10.8 second for GMWTSEC, and 3.75 steps for GMSTEP. CONCLUSION: In our study, we investigated the utility of ambulatory assessment tools to predict dementia. The results of this study suggest that the 4MWT and the GMWT used in this study are appropriate assessment tools for dementia prediction.

• PNF and Movement
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• v.18 no.2
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• pp.215-222
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• 2020

Purpose: The study investigated the effect on chronic stroke patients' balance of a weight shift to the affected side using an insole on the less affected side during treadmill walking training. Methods: The subjects were 7 patients who had been diagnosed with stroke 6-24 months prior to the study. In each case, an insole was applied on the patient's less affected side during treadmill walking training. Each training session lasted 30 minutes and was undertaken 5 times per week for 4 weeks. Biorescue equipment that measures shifts in center of pressure was used to assess balance ability as measured by the Korea-Berg balance scale (K-BBS) before and after each training intervention. The Wilcoxon signed-rank test was used to evaluate within-group effects. Results: The results revealed statistically significant before and after differences in area, pressure, length, and mean velocity of the balance test and on K-BBS (p < 0.05). Conclusion: In chronic stroke patients, using an insole to adjust the height of the shoe on the less affected side is an effective means of increasing weight-shifting on the paralyzed side during treadmill gait training.

• PNF and Movement
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• v.16 no.1
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• pp.67-73
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• 2018

Purpose: Smartphones, which are widely used worldwide to detect acceleration and position, have been used in the area of rehabilitation medicine in recent clinical research studies and tests. The aim of the present study was to determine the feasibility of using a smartphone application based on center of movement (COM) displacement to measure gait parameters in stroke patients in the clinical field of rehabilitation medicine. Methods: The study consisted of 30 stroke patients. The COM was measured using a smartphone application, Gait Analysis Pro, during a 6-m walk. Each patient performed three 6-m walking trials, and the smartphone application measured gait duration, gait speed, step length, cadence, and vertical and lateral displacement of the COM. The Kolmogorov-Smirnov test was conducted to determine the normality in gait parameters, and a repeated one-way analysis of variance (ANOVA) was performed to determine the consistency among the three trials. A p value of 0.05 was considered statistically significant in all the tests. Results: In all the measured parameters, the smartphone application showed a normal distribution, as shown by the results of the Kolmogorov-Smirnov test. There were no significant differences among the three repetitive walking trials. Conclusion: These results suggest that the smartphone application can be used for evaluating gait in stroke patients, as well as in healthy adults. However, prior to using the smartphone application in the clinical field, further research involving three-dimensional gait analysis is needed to enhance the confidence level of the findings.

• Korean Journal of Applied Biomechanics
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• v.20 no.2
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• pp.221-230
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• 2010

The purpose of this study was to analyze biomechanical factors of trail running shoes applied to korean shoe-lasts. 10 healthy male subjects with an average age of 37.2 years(SD=8.28), weight of 69.6 kg(SD=10.56) and a height of 171 cm(SD=4.93) were recruited for this study. Ten males walked on a treadmill wearing four different shoes. Foot pressure data was collected using a Pedar-X mobile system(Novel Gmbh., Germany) operating at the 1000 Hz. Surface EMG signals for tibialis anterior, gastrocnemius, vastus lateralis and biceps femoris were acquired at 1000 Hz using Noraxon TeleMyo DTS system(Noraxon Inc., USA). Foot pressure and leg muscle fatigue were measured and calculated during walking. The results are as follows: After walking 60 minutes, Type A showed a lower MPF. MPF values were significantly different from each muscle(p<.05). Therefore, Type A shoe might decrease muscle fatigue in the legs while walking. In addition, Type It showed that Type A shoe has the highest contact area and the lowest maximum pressure. As a result of the analysis, Trail running shoes will use a new design to reduce muscle fatigue and are expected to increase comfort and fitting.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.17 no.2
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• pp.19-24
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• 2011

Background: The elderly are likely to fall due to physical and mental atrophies, and experiencing falls may result in fear of falls and lack of self-confidence, which also leads to hesitation to physical activities and changes in walk and balance, the major variables in independent daily life. Methods: In three senior citizen centers located in D city, 22 elderly women aged 65 or older were chosen, and they filled in the questionnaire which included their agreement to voluntarily participate in the survey and medical histories. As to whether they had falls experience, the medical history items in the questionnaire asked them if they had falling down or falls once a year, twice for the three years. The objects were divided to NFE (non-falls experience) and FE (falls experience). Results: 1. As to walking abilities, significant difference was found between NFE and FE regarding walk width, stepping with two feet, and stride length while there was no significant different in terms of cadence. 2. As to balancing abilities, was significant difference between NFE and FE in terms of the physical body center area. As to the sit-to-stand, tandom gait test, no significant difference was found, and neither in the timed up and go test. Conclusions: The elderly with falls experience has inferior walking and balancing abilities to those without falls experience, and thus they are more exposed to the risks of falls.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.3
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• pp.249-256
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• 2016

Recently, a number of techniques to ensure the free walking for the visually impaired and transportation vulnerable have been studied. As a device for free walking, there are such as a smart cane and smart glasses to use the computer vision, ultrasonic sensor, acceleration sensor technology. In a typical technique, such as techniques for finds object and detect obstacles and walking area and recognizes the symbol information for notice environment information. In this paper, we studied recognization algorithm of the selected symbols that are required to visually impaired, with the deep learning algorithm. As a results, Use CNN(Convolutional Nueral Network) technique used in the field of deep-learning image processing, and analyzed by comparing through experimentation with various deep learning architectures.

• Journal of the Korean Society of Safety
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• v.38 no.2
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• pp.87-95
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• 2023

On October 29, 2022, a very large number of people gathered in Itaewondong, Yongsan-gu, Seoul, Korea for a Halloween festival, and as crowds pushed through narrow alleys, 159 deaths and 195 injuries occurred, making it the largest crushing incident in Korea. There have been a number of stampede deaths where crowds gathered at large-scale festivals, event venues, and stadiums, both at home and abroad. When the density increases, the physical contact between bodies becomes very strong, and crowd turbulence occurs when the force of the crowd is suddenly added from one body to another; thus, the force is amplified and causes the crowd to behave like a mass of fluid. When crowd turbulence occurs, people cannot control themselves and are pushed into he crowd. To prevent a stampede accident, investigation and management of areas expected to be crowded and congested must be systematically conducted, and related ministries and local governments are planning to establish a crowd management system to prepare safety management measures to prevent accidents involving multiple crowds. In this study, based on national data, a continuous digital topographic map is modeled in 3D to analyze the risk of crowding and present a plan for selecting high-risk walking routes. Areas with a high risk of crowding are selected in advance based on various data (numerical data, floating population, and regional data) in a realistic and feasible way, and the analysis is based on the visible results from 3D modeling of the risk area. The study demonstrates that it is possible to prepare measures to prevent cluster accidents that can reflect the characteristics of the region.