• Journal of Institute of Control, Robotics and Systems
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• v.16 no.5
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• pp.440-445
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• 2010

This paper proposes a single accelerometer sensor control algorithm to mobile inverted pendulum, generally called 'Segway', and evaluates the performance of this system comparing to the conventional ones. The commercialized 'Prototype Segway-PT' is initially considered as a next-generation transport vehicle. However, this robot is operated by three gyroscopes and two accelerometers to control the posture and speed, and it requires the complex signal processing for fusing the two sets of data. As the result of this, the growth rate of market size of 'Segway' is slow because of its high price mainly. In this paper, the mobile inverted pendulum is operated by a single accelerometer to simplify the control system to lower the price. Low pass filter is one of the good sensors to reducing the variation of an accelerometer, but it has time delay. This time delay disturbs real-time mobile inverted pendulum control. Like this, other various algorithms are used for this system, but each one has its own weak point. So this paper proposes a new filtering method, median filter and EKF. Median filter is used to image processing to reject impulse elements like salt and pepper noise. As the major performance evaluation parameter for the accelerometer, the high-frequency to low frequency ratio from FFT (Fast Fourier Transform) is used. Effectiveness of the proposed algorithms has been verified through the real experiments and the results are demonstrated.

• Journal of International Academy of Physical Therapy Research
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• v.4 no.1
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• pp.505-509
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• 2013

This study has investigated the effect of isometric contractile force and muscle activity applying sperficial heat according to the time from the biceps brachii muscle. In this study, 20 university students participants without musculoskeletal and neurological disorders. By applying a hot pack 5min, 10min, 20min and 30min respectively. After that measurement are skin temperature, contractile force and muscle activity. Skin temperature of the hot 5 min applied that rapidly changing. Increasing the time it takes to apply a variance has been reduced(p<.001). Isometric contractile force was not statistically significant but highest when applying the hot pack 5 minutes and lowest when applying the hot pack 30 minutes(p<.001). Muscle activity and median frequency was highest when applying the hot pack 5 minutes. To analyze the above results, it was found that isometric contractile force and muscle activity changed according to the applying time. These result lead us to the conclusion that this study will be more evidence for changes in muscle contraction to apply hot pack on clinic.

• Journal of the Korean Society of Physical Medicine
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• v.13 no.4
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• pp.9-17
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• 2018

PURPOSE: This study was conducted to compare the effects of the Graston-based massage method and microcurrent application on muscle fatigue after causing muscle fatigue of the quadriceps femoris by applying high-intensity exercise. METHODS: Study subjects (56 healthy subjects in their 20s) were randomized into a microcurrent group (MG), Graston group (GG), and control group (CG). To induce fatigue of the quadriceps femoris, the subjects performed squats 100 times without a break within about 5 minutes. Muscle fatigue was measured immediately after performing squats and 15 minutes after intervention. To measure muscle fatigue, surface electromyogram (EMG) was used to obtain and compare the median frequency. Microcurrent or Graston massage was applied to their quadriceps muscles 15 minutes after performing the squats. RESULTS: Muscle fatigue increased significantly in the vastus lateralis before and after intervention in the Graston group (p<.05), while no significant difference was observed in the rectus femoris and vastus medialis (p>.05). There were also no significant differences in the microcurrent group or the control group. CONCLUSION: Both the microcurrent group and Graston group showed a tendency for increasing median frequency values compared to the control group, but there was no significant difference except in the vastus lateralis treated with the Graston technique. Although there was no significant difference, the Graston technique could be utilized to reduce the occurrence of DOMS by preventing muscle fatigue in clinical practice or sports medicine.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.10a
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• pp.118-120
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• 2021

In modern society, with the development of IoT technology, various digital equipment is being distributed in a wide range of fields such as CCTV and exploration robots. Accordingly, the importance of data processing is increasing, and various studies are being conducted to remove noise generated in the process of receiving data in the imaging field. Representative noise includes additive white Gaussian noise (AWGN), and existing filters for removing noise include an average filter (AF), an alpha trimmed average filter (A-TAF), and a median filter (MF). However, existing filters have a disadvantage in that they show somewhat insufficient performance in noise removal characteristics in high frequency areas. Therefore, in this paper, in order to effectively remove AWGN existing in the high frequency region, a weight filter according to a distance based on the standard deviation is proposed.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.117-124
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• 2006

The modern convenient life formed by industrial development becomes lack of exercise and takes an interest in diet. Specially, professional walking shoes is developed as people take an interest in jogging, Those shoes, professional walking shoes or Dietshoes, increase exercise effects by change of heel types. Therefore, this study investigated motility effects by EMG experiment in order to measure Muscle Activities (MA) while wearing diet shoes (backless). Experiment was conducted by EMG measurement, from calf (gastrocnemius muscle), thigh (vastus muscle) and waist (erector spinae muscle), of 12 high school students. Exercise effects between the two shoes were analyzed by EMG (MF; Median Frequency, MPF; Mean Power Frequency, ZCR; Zero Crossing Rate). Results showed that the Dietshoes(MF: 48.21Hz, MPF: 65.0Hz, ZCR: 100.6Hz) had larger EMG value than that of Normal shoes(MF: 40.47Hz, MPF: 58.04Hz, ZCR: 82.09Hz). Also, in MA, the highest activities are showed in the calf, the second one is in waist, and last one is in thigh during gate. ANOVA between shoes in measurement parts showed significant effects in MF (gastrocnemius: p-value=.022, vastus laterals: p-value=.037, erector spinae: p-value=.082), MPF (gastrocnemius: p-value=.032, vastus laterals: p-value=.046, erector spinae: p-value=.090), and ZCR (gastrocnemius: p-value=.000, vastus laterals: p-value=.004, erector spinae: p-value=.134). And MA of Dietshoes is higher than that of Normal shoes, and decreasing rate of MA in Dietshoes is less than that of Normal shoes. Thus, this study validates exercise effects of Dietshoes.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.104-112
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• 2021

Objective: This study aimed to analyze the effects of consecutive whole body vibration through heel raise posture on the center of pressure and electromyography of anterior tibial muscle, lateral gastrocnemius and soleus muscles during single-leg stance. Method: The subjects of this study included 30 healthy males in their 20's, with the following inclusion criteria: no history of orthopaedic medical history, no participation in regular exercises, no history of whole body vibration exercise, and right leg being the dominant leg. The experimental procedure involved pretreatment measurement of eye open single-leg stance, application of whole body vibration for 30 seconds, post-treatment measurement (3 measurements in total). Static and dynamic movements have been measured over 2 separate experiments, with 72 hours gap between the experiments. Static movement involved maintaining single-leg heel raise posture for 30 seconds while applying whole body vibration, and dynamic movement involved heel raise (15 repetitions over 30 seconds) while applying whole body vibration. The strength of applied whole body vibration was 35 Hz frequency and 2~4 mm amplitude. Results: As the single-leg posture after static heel raise posture, mediolateral velocity of the center of pressure at post 2 and post 3 were significantly reduced compared to the pre-treatment measurement. In addition, the percentage for reference voluntary contraction in anterior tibial muscle and soleus and median frequency at anterior tibial muscle and lateral gastrocnemius muscle at post 3 were significantly decreased compared to the pre-treatment value. As the single-leg posture after dynamic heel raise posture, the mediolateral 95% edge frequency of the center of pressure and median frequency at anterior tibial muscle, lateral gastrocnemius muscle, and soleus muscle at post 3 were significantly reduced compared to the pre-treatment value. Conclusion: Acute whole body vibration via static and dynamic heel raise posture have positive effect on mediolateral posture control during single-leg stance.

• The Korean Journal of Food And Nutrition
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• v.33 no.6
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• pp.721-731
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• 2020

This study used a food-frequency questionnaire to estimate fruit consumption by sex, age, and type of fruit to analyze the association between fruit type and metabolic factors. Using food-frequency-questionnaire data from 3,091 adults aged 19~64 years (1,184 men and 1,907 women) in the 2016 Korea National Health and Nutrition Examination Survey, this study analyzed weekly fruit consumption and the consumption frequency of strawberry, oriental melon, watermelon, peach, grape, apple, pear, persimmon/dried persimmon, tangerine, banana, orange, and kiwi by sex and age groups. Apple was the most-consumed fruit (459.45 g/wk), followed by pear (165.80 g/wk), watermelon (124.80 g/wk), and banana (115.32 g/wk). After adjustment for confounding factors, ED: Please give examples. in the women who ate more than the median consumption of apple, the prevalence of hyperglycemia was 27.4% (OR: 0.726, 95% CI: 0.539~0.979) (p=0.0362), and of high triglycerides, 25.7% (OR: 0.743, 95% CI: 0.564~0.978) (p=0.0340). These rates were lower than those of women who ate less than the median consumption of apple. The results of this study suggest that apple consumption helps improve metabolic indicators in Korean adults.

• Magazine of the Korean Society of Agricultural Engineers
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• v.32 no.E
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• pp.20-32
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• 1990

Abstract This study was conducted to pursue the normalization of frequency distribution by making an approach to the coefficient of skewness to nearly zero through the Box-Cox transformation, to get probable flood flows can be calculated by means of the transformation equation which has been derivated by Box-Cox transformation in the annual maximum series of the applied watersheds. It has been concluded that Box-Cox transfromation is proved to be more efficient than logarithmic, square root and SMEMAX transformation which is based on the trigonometric solution of a right triangle whose three verteces repesent the smallest, median and largest observed values of a population in making the coefficient of skewness nearer to zero. Consequently it is shown that probable flood flows according to the return period based on Box-Cox transformation are closer to the observed data as compared to other methods including SMEMAX transformation and fitted probability distributions such as the three parameter lognormal and the type I extremal distribution for the applied watersheds.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 1997.11a
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• pp.91-101
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• 1997

The demand for handling images in digital form has increased dramatically in recent years. Digital image compression is required to store and transmit mass information in different from general information. JPEG(Joint Photographic Experts Group) committee founded by CCITT and ISO is define the still-image standard compression/restoration algorithm. JPEG is proposed the standard of grayscale and color still-image compression/restoration. In the image quality, JPEG is applicable to the various applications in which compression is able to from 1/10 to 1/50 without the visible obstacle. In this paper, we proposed that the proposed method enhance the compression ratio which is reducing the higher frequency in order to increasing the spatial redundancy in the image. The proposed method is using the low pass filter in order to reducing the higher frequency. The low-pass filters are using the median filter and convolution filter in the spatial domain, FFT filter in the frequency domain. We acquired the additive compression ratio reducing the higher frequency using the low-pass filter.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.4
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• pp.729-734
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• 2008

Vibroarthrographic(VAG) signals, emitted by human knee joints, are non-stationary and multi-component in nature and time-frequency distributions(TFD) provide powerful means to analyze such signals. The objective of this paper is to classify VAG signals, generated during joint movement, into two groups(normal and patient group) using the characteristic parameters extracted by time-frequency transform, and to evaluate the classification accuracy. Noise within TFD was reduced by singular value decomposition and back-propagation neural network(BPNN) was used for classifying VAG signals. The characteristic parameters consist of the energy parameter, energy spread parameter, frequency parameter, frequency spread parameter by Wigner-Ville distribution and the amplitude of frequency distribution, the mean and the median frequency by fast Fourier transform. Totally 1408 segments(normal 1031, patient 377) were used for training and evaluating BPNN. As a result, the average value of the classification accuracy was 92.3(standard deviation ${\pm}0.9$)%. The proposed method was independent of clinical information, and showed good potential for non-invasive diagnosis and monitoring of joint disorders such as osteoarthritis and chondromalacia patella.