• Journal of Life Science
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• v.19 no.10
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• pp.1368-1373
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• 2009

The purpose of this study was to assess the influence of waist size on the reliability and validity of pedometers to count steps in children and youth. The participants for this study were 20 children and youth, composed of 14 Hispanic and 6 Caucasian children. Ten children and youth had waist circumferences greater than the $85^{th}$ percentile (Body Mass Index (BMI)=$28.91\pm3.07$), and 10 children and youth had waist circumferences smaller than the $50^{th}$ percentile (BMI=$18.05\pm1.55$). To examine pedometer reliability, each child completed 3 ascent and descent trials up a set of 15 stairs while wearing a Yamax SW-701 pedometer. The main effect of trials was not statistically significant for the stair ascent trials F (2, 36)=2.575 or for the descent trials F (2, 36)=0.235. The trial by group interaction was also not statistically significant. To examine the influence of waist circumference on the validity of the pedometer in counting walking steps at a self-selected walking pace, the children and youth in the two groups completed a 400-m course. The main effect on the groups was statistically significant, F (1, 18)=7.489. The main effect of counting techniques was not statistically significant, F (1, 18)=2.983 (hand-counted vs. pedometer counted). Overall, the trial and trial by group interaction comparisons for the 400-m walk were not statistically significant, suggesting that the pedometer was equally valid as a tool for assessing walking steps in high waist circumference (HWC) and low waist circumference (LWC) in children and youth.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.9
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• pp.420-422
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• 2006

This paper proposes a new method to count the number of steps for personal navigation systems. The proposed method resolves the mis-counting problem caused by the variation of the ground and walking behavior. To this end, a 2-axis accelerometer is utilized and a reliable step counting algorithm is developed. Experimental test was carried out to show the effectiveness of the proposed method. Test results show that the proposed method gives a robust performance for several types of ground and walking behavior.

• Journal of Korean Biological Nursing Science
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• v.17 no.2
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• pp.89-96
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• 2015

Purpose: Despite well-known benefits of walking on cardiovascular health, no structured walking exercise program has been formally tested on elderly Korean immigrants (EKIs). This pilot randomized controlled trial study assessed the effect of a walking program on walking behavior (pedometer steps count), stress (cortisol), depressive symptoms (CESD-10), and cardiovascular disease biomarkers (hs-CRP and fibrinogen) via venipuncture in EKIs. Methods: Seventy EKIs recruited from a Korean community were randomly assigned to a 12-week walking group or control group in a 3:2 ratio. The working program included a pedometer, buddy, monthly coffee card, weekly call for goal setting, and physical activity consultation. Walking group EKIs maintained the Centers for Disease Control and Prevention recommended exercise guidelines and good mental health status over 12 weeks. Results: There was no significant difference in the outcomes between control and walking groups. Conclusion: Social networking with Koreans in the senior center and church from a well-established Korean community might have positive effects on mental health.

• Journal of the Korean Dietetic Association
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• v.11 no.2
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• pp.159-169
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• 2005

The purpose of this study was to assess the energy expenditure and investigate the relationship between related variables in 70 female university students. Resting energy expenditure estimated by Harris-Benedict formula, WHO/NAO/FAO formula and various formulas based on body weight and body surface area were 1366.9$\pm$74.4kcal/day, 1287.8$\pm$106.6kcal/day, 1171.4$\pm$155.8kcal/day and 1342.0$\pm$97.4kcal/day. Measured resting energy expenditure by indirect calorimetry(Model : Metavine and TrueOne2400) were 1582.0$\pm$150.1kcal/day and 1268.2$\pm$152.9kcal/day, respectively. Average step number per day was 11981.2$\pm$3014.4 steps and average step number per hour was 746.1$\pm$198.0 steps/hr. Daily energy expenditure by using Harris-Benedict formula, body weight formula, body surface area formula, WHO/NAO.FAO formula and 15-min check list formula were 2374.7$\pm$249.6kcal, 2033.5$\pm$313.2kcal, 2331.2$\pm$266.0kcal, 2240.8$\pm$185.5kcal and 2195.5$\pm$398.3kcal. Meanwhile energy intake of subjects was 1714.9$\pm$551.2 kcal. Daily energy expenditure has positive correlation(r=0.262) with daily step number. And there was significant positive correlations(r=0.35-0.68) between various daily energy expenditures and muscle mass. These results suggested that increase of daily step number by using pedometer is good method to increase daily energy expenditure. In particular, increase in step number can reinforce the amounts of muscle.

• Design Convergence Study
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• v.16 no.6
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• pp.123-135
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• 2017

In recent mobile health care service, health management using number of steps is becoming popular. In addition, a variety of activity trackers have made it possible to measure the number of steps more accurately and easily. Nevertheless, the activity tracker is not popularized, and it is a trend to use the pedometer sensor of the smartphone as an alternative. In this study, we tried to find out how much the number of steps collected by the smartphone versus the actual number of steps in actual situations, and what factors make the difference. We conducted an experiment to collect number of steps data of 21 people using the smartphone and wearable device simultaneously for 7 days. As a result, we found that the average number of steps of the smartphone is 62% compared to the actual number of steps, and that there is a large variation among users. We derived a regression model in which the accuracy of smartphone increases with the degree of awareness of smartphone. We expect that this can be used as a factor to correct the difference from the actual number of steps in the smartphone alone healthcare service.

• Journal of Nutrition and Health
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• v.40 no.6
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• pp.576-583
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• 2007

The purpose of this study was to assess the daily steps, physical activities and activity coefficient of policemen (average age: 31.5 ${\pm}$ 5.1 years) who do shift work. Body weight, height and daily steps were measured and one-day activity diary was collected by interviewing with policemen. Average height, body weight, BMI, body fat (%) and muscles (%) of subjects were 173.1 ${\pm}$ 5.2 cm, 73.7 ${\pm}$ 9.7 kg, 24,6 $kg/m^{2}$, 15.5 ${\pm}$ 1.9% and 37.3 ${\pm}$ 5.8%, respectively. The average daily numbers of steps were found to be 9,812 steps/day on day shift duty and 10,888 steps/day on night shift duty and 6,551 steps/day on holiday duty. Hourly step rates on day shift, night shift and holiday came to 1946 steps/hr, 2,130 steps/hr and 1,318 steps/hr, respectively. Activity coefficient (1.75) in night shift of the subjects was the highest and activity coefficient (1.52) in day shift was significantly higher than that (1.31) in holiday (p < 0.05). The rate of expending time for very light activity in holiday (91.5%) was significantly higher than that (70.0%) in night shift. The muscle mass (kg, %) had significantly positive relationship with daily steps in day shift (r = 0.592, r = 0.632) and night shift (r = 0.550, r = 0.503). Triceps skinfold thickness was negatively correlated with daily steps in day shift (r = -0.366, p < 0.05). There were remarkable differences in physical activities and sleeping hours depending on shift works of policemen. In the case of night shift work, sleeping hours was the lowest and activity coefficient was the highest among day shift, night shift and holiday. These results suggest that energy requirements of policemen should be differentiated according to shift work duty.

• Korean Journal of Community Nutrition
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• v.12 no.3
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• pp.361-371
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• 2007

The purpose of this study was to assess the daily steps, physical activities and activity coefficient of the elementary school children in the rural area. Body weight, height and daily steps were measured and one-day activity diaries were collected by interviewing children. The average age of the subjects was $9.96{\pm}1.02$ years. Average height, weight, obesity index, body fat and muscle of subjects were $136.2{\pm}8.9cm,\;35.2{\pm}8.5kg,\;99.6{\pm}18.8%,\;22.9{\pm}8.5%\;and\;35.8{\pm}6.0%$, respectively. The average daily steps of the subjects was 17,584 and daily steps (19,314) of 3rd grade students was significantly higher than that (15,712) of 5th grade children. But there was no significant difference in daily steps and activity coefficients between boys and girls. Daily steps (23,347) of exercise group showed the significantly higher than that (16,144) of non-exercise group. Gender and grade of subjects did not have significant influence on activity coefficients, but there was a significant difference in activity coefficient on weekdays between the exercise group ($1.82{\pm}0.30$) and non-exercise group ($1.50{\pm}0.21$). Analysis of variance revealed stronger associations between daily steps and body fat (%) than between daily steps and BMI. Daily steps showed significant negative correlation with body fat (%) measured using two methods r=-0.321 and r=-0.365, respectively. Activity coefficient was significantly correlated (r=0.436) with daily steps, thus increasing daily steps cm prevent and treat childhood obesity by increasing the energy expenditure. The higher activity coefficients (weekday 1.56, weekend 1.53) of the subjects was caused by the fact that rural students spent more time outside and enjoyed stronger activities than urban students. The results of this study can be used to estimate energy requirements for Korean children based on exercise levels and living areas.

• Journal of the Korean Dietetic Association
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• v.12 no.3
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• pp.277-288
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• 2006

The purpose of this study was to assess the energy expenditure and investigate the relationship between related variables of 57 dieticians in Youngdong-area. The average daily number of steps was found to be 9358.0$\pm$2714.3 steps/day on weekdays and 7862.9$\pm$2504.9 steps/day during weekends. Hourly step rates on weekdays and weekends came to 570.6$\pm$249.8 steps/hr and 564.0$\pm$224.8 steps/hr, respectively. Activity coefficient of subjects was higher on weekdays (1.56) than weekends (1.51, p<0.05). Resting energy expenditure estimated by the Harris-Benedict formula, WHO/NAO/FAO formula as well as formulas based on body surface area and DRIs (Dietary Reference Intake for Koreans) were calculated to be 1333.7$\pm$89.5kcal/day, 1351.0$\pm$123.3kcal/day, 1388.5$\pm$100.3kcal/day and 1295.9$\pm$90.8kcal/day, respectively. Using these resting energy expenditures and the activity coefficients, daily energy expenditures were calculated to be from 2039.7kcal/day to 2183.5kcal/day on weekdays and from 2016.1kcal/day to 2159.2kcal/day on weekends. Meanwhile energy intakes of subjects on weekdays and weekends were 1594.7$\pm$698.3kcal and 2152.9$\pm$768.0kcal, respectively. The activity coefficient (1.49) of dieticians who managed less than 500 meals per day was significantly lower than that of dieticians who served more than 500 meals per day. Dieticians of schools located in rural areas had higher activity coefficient (1.59) than those of schools located in urban or island settings. These results suggest that work analysis and development of management strategies are necessary to improve dieticians' productivity.

• Journal of the Korea Society of Computer and Information
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• v.17 no.8
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• pp.107-114
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• 2012

We have developed a textile capacitive pressure sensor for smart gait analysis. The proposed system can convert sensor signal into step counts and pressure levels by different posture. To evaluate the performance of insole type textile capacitive sensor, we measured capacitance change by increment of weights from 10 kg to 100 kg with 10 kg increment using M1 class rectangular weights (four 20 kg weights and two 10 kg weights) which have ${\pm}10%$ tolerance. The result showed non-linearity characteristic of a general capacitive pressure sensor. The test was performed according to a test protocol for four different postures (sitting, standing, standing on a left leg and standing on a right leg) and different walking speeds (1 km/h and 4 km/h). Five healthy male subjects were participated in each test. As we expected, the pressure level was changed by pressure distribution according to posture. Also, developed textile pressure sensor showed higher recognition rate (average 98.06 %) than commercial pedometer at all walking speed. Therefore, the proposed step counts and posture monitoring system using conductive textile capacitive pressure sensor proved to be a reliable and useful tool for monitoring gait parameters.

• Journal of the Korea Society of Computer and Information
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• v.19 no.5
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• pp.43-52
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• 2014

In this paper, we propose Gravity Removal and Vector Rotation algorithm for counting steps of wearable device, and we evaluated the proposed GRVR algorithm with Micro-Electro-Mechanical (MEMS) 3-axis accelerometer equipped in low-power wearable device while the device is mounted on various positions of a walking or running person. By applying low-pass filter, the gravity elements are canceled from acceleration on each axis of yaw, pitch and roll. In addition to DC-bias removal and the low-pass filtering, the proposed GRVR calculates acceleration only on the yaw-axis while a person is walking or running thus we count the step even if the wearable device's axis are rotated during walking or running. The experimental result shows 99.4% accuracies for the cases where the wearable device is mounted in the middle and on the right of the belt, and 91.1% accuracy which is more accurate than 83% of commercial 3-axis pedometer when worn on wrist for the case of axis-rotation.