• Korean Journal of Applied Biomechanics
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• v.22 no.4
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• pp.429-435
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• 2012

The purpose of this study was to determine the biomechanical effect of wearing carbon nanotube-based insole on cushioning and muscle tuning during drop landing. Twenty male university students(age: $21.2{\pm}1.5yrs$, height: $175.4{\pm}4.7cm$, weight: $70.2{\pm}5.8kg$) who have no musculoskeletal disorder were recruited as the subjects. Average axial strain, average shear strain, inversion angle, linear velocity, angular velocity, vertical GRF and loading rate were determined for each trial. For each dependent variable, a one-way analysis of variance(ANOVA) with repeated measures was performed to test if significant difference existed among different three conditions(p<.05). The results showed that Average axial strain of line 4 was significantly less in CNT compared with EVA and PU during IP phase. The average shear strain was less in CNT compared with EVA and PU during other phases. The inversion angle was increased in CNT compared with EVA and PU during all phase. In linear velocity, angular velocity, vertical GRF and loading rate, there were no significant difference between the three groups. This result seems that fine particle of carbon nanotube couldn't make geometric form which can absolve impact force by increasing density through eliminating voids of forms. Thus, searching for methods that keep voids of forms may play a pivotal role in developing of insole. This has led to suggestions of the need for further biomechanical analysis to these factors.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.348-357
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• 2019

To investigate the changes of dominant species of benthic macroinvertebrates following summer precipitation variance, we surveyed twenty five sites of the main Seomjin River in May and September in 2014 and 2015. The temperature, precipitation, water quality factors and substrate composition, water depth and flow velocity, which are important factors in benthos habitat environment, were collected and measured. There is not much difference of the cumulative precipitation (CP) between 2014 (2,322.1 mm) and 2015 (2,371.0 mm) in May. However CP in september was decreased by more than half in 2015 (3,726.1 mm) than 2014 (7,678.2 mm). Due to washing effect by summer precipitation, total number of species and individuals for benthic macroinvertebrates were higher in May than in September. Chironomidae spp. and Choroterpes altioculus were dominated in May, Ecdyonurus levis, Ecdyonurus kibunensis were dominated in September. As a result of correlation analysis between community indices and environment factors, it was found that there is a significant correlation with flow velocity and substrate compositions. According to the results of cluster analysis and PCA based on environment fators and dominant species of benthic macroinvertebrates in Seomjin River, it was divided into four groups following CP and MT. Ecdyonurus levis and Ecdyonurus kibunensis reflect the effect of the decrease in summer precipitation.

• Fisheries and Aquatic Sciences
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• v.1 no.1
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• pp.48-62
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• 1998

Seasonal volume transport on the Texas-Louisiana continental shelf is investigated in terms of objectively fitted transport streamfunction fields based on the current meter data of the Texas­Louisiana Shelf Circulation and Transport Processes Study. Adopted here for the objective mapping is a method employing a two-dimensional truncated Fourier representation of the streamfunction over a domain, with the amplitudes determined by least square fit of the observation. The fitting was done with depth-averaged flow rather than depth-integrated flow to reduce the root-mean-square error. The fitting process filters out $11\%$ of the kinetic energy in the monthly mean transport fields. The shelf-wide pattern of streamfunction fields is similar to that of near-surface velocity fields over the region. The nearshore transport, about 0.1 to 0.3 Sv $(1 Sv= 10^6\;m^3/sec)$, is well correlated with the seasonal signal of along-shelf wind stress. The spring transport is weak compared to other seasons in the inner shelf region. The transport along the shelf break is large and variable. In the southwestern shelf break, transport amounts up to 4.7 Sv, which is associated with the activities of the encroaching of energetic anticyclonic eddies originated in Loop Current of the eastern Gulf of Mexico. The first empirical orthogonal function (EOF) of streamfunction variability contains $67.3\%$ of the variance and shows a simple, shelf-wide, along-shelf pattern of transport. The amplitude evolution of the first EOF is highly correlated (correlation coefficient: 0.88) with the evolution of the along-shelf wind stress. This provides strong evidence that the large portion of seasonal variation of the shelf transport is wind-forced. The second EOF contains $23.7\%$ of the variance and shows eddy activities at the southwestern shelf break. The correlation coefficient between the amplitudes of the second EOF and wind stress is 0.42. We assume that this mode is coupled a periodic inner shelf process with a non-periodic eddy process on the shelf break. The third EOF (accounting for $7.2\% of the variance) shows several cell structures near the shelf break associated with the variability of the Loop Current Eddies. The amplitude time series of the third EOF show little correlation with the along-shelf wind.

• Korean Journal of Applied Biomechanics
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• v.22 no.2
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• pp.253-259
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• 2012

The purpose of this study was to determine how smartphone use posture affects biomechanical variables and muscle activities. Eleven university students(age: $22.2{\pm}2.6$ yrs, height: $176.6{\pm}4.7$ cm, weight: $69.5{\pm}7.5$ kg) who have no musculoskeletal disorder were recruited as the subject according to having experience in using the smartphone for more than one year. Angular velocity, muscle activity, and thumb finger pressure were determined for each trial. For each dependent variable, a one-way analysis of variance (ANOVA) with repeated measures was performed to test if significant difference existed among different three conditions (p<.05). The result showed that rotational angular velocity of the first metacarpal were increased in DESK posture compared with STAND posture during SU phase. The average nEMG values of FDI(First dorsal interosseous) were less in SIT and DESK posture compared with STAND posture during SR phase. These indicated that smartphone postures may effect the thumb ROM(Range of motion) and muscle activity. This has led to suggestions of the need for further kinetic and EMG analyses to evaluate best assess and characterize with smartphone use.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.4 no.1
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• pp.10-21
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• 2001

A new method of laser remote sensing is proposed, based on sensing the sea surface by a narrow laser beam (2-3cm) and analyzing statistically specular reflections. Construction of the angular dependency of the average density of specks versus the aircraft flight horizontal azimuth allows calculation of both intensity and azimuthal properties of the sea surface spectrum. The paper contains the experimental setup and technique, the field measurement data taken onboard an aircraft and the examples of calculated main statistical parameters of sea waves. Their energy-carrying component velocity is found by the mean velocity of an ensemble of specular points at the random sea surface. The surface wave nonlinearity is shown to affect substantially the statistical characteristics measured: mean numbers of specular areas with th given elevation and given slope, arranged along the line of crossing the sea surface by the scanning laser beam. Experimental measurement of a variance in the number of these areas yields a principal possibility to calculate the correlation function of the sea surface without its preliminary modeling.

• The Korean Journal of Applied Statistics
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• v.22 no.3
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• pp.515-530
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• 2009

Evaporation from surface water bodies is influenced by a number of meteorological parameters. The rate of evaporation is primarily controlled by incoming solar radiation, air and water temperature and wind speed and relative humidity. In the present study, influence of weekly meteorological variables such as air temperature, relative humidity, bright sunshine hours, wind speed, wind velocity, rainfall on rate of evaporation has been examined using 35 years(1971-2005) of meteorological data. Statistical analysis was carried out employing linear regression models. The developed regression models were tested for goodness of fit, multicollinearity along with normality test and constant variance test. These regression models were subsequently validated using the observed and predicted parameter estimates with the meteorological data of the year 2005. Further these models were checked with time order sequence of residual plots to identify the trend of the scatter plot and then new standardized regression models were developed using standardized equations. The highest significant positive correlation was observed between pan evaporation and maximum air temperature. Mean air temperature and wind velocity have highly significant influence on pan evaporation whereas minimum air temperature, relative humidity and wind direction have no such significant influence.

• PNF and Movement
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• v.16 no.1
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• pp.151-159
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• 2018

Purpose: The aim of this study was to examine the activation of the contralateral upper and lower extremities and trunk muscle during ipsilateral upper extremity diagonal isokinetic exercise. Methods: Twenty-one healthy male subjects with no history of shoulder injury undertook ipsilateral diagonal isokinetic exercise at 60, 120, and $180^{\circ}/sec$, utilizing a standard Biodex protocol. Muscle activation amplitudes were measured in the upper trapezius, pectoralis major, biceps brachii, rectus abdominis, external oblique, rectus femoris, adductor longus, and biceps femoris muscles using electromyography. A one-way analysis of variance and paired t-tests were conducted, and the data were analyzed using SPSS, version 21.0. Results: The results revealed no statistically significant interaction between motion and angular velocity and no statistically significant contralateral muscle activation according to angular velocity (p>0.05). However, they revealed statistically significant contralateral muscle activation according to motion (p<0.05). Conclusion: These results suggest that the movements involved in contralateral upper extremity diagonal isokinetic exercise can enhance muscle strength in patients affected by stroke, fracture, burns, or arthritis.

• Journal of Korean Society for Atmospheric Environment
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• v.11 no.4
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• pp.361-367
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• 1995

This study has been carried out to investigate the filteration performance of Electrostatically Stimulated Fabric Filter(ESFF) at high temperature condition. The electric field was maintained parallel to the fabric surface. The benefits of ESFF are lower residual pressure drop, improvement of fine particle removal efficiency and increasing reduced rate of pressure drop during a filteration cycle, stable operation at higher filtering velocities. According to the variance of filtering velocities and dust loadings, the results are summarized as follows; By imposing an electric field on the filter, the reduced rate of pressure drop was 7.sim.18% at room temperature, and when filtering velocity was 1.8m/min and dust loading was 1g/m$^{3}$, the value of reduced rate of pressure drop was shown the highest. Under the electric field around the filter, the reduced rate of pressure drop was 10.sim.35% at high temperature, and when filtering velocity was 1.8m/min and dust loading was 1g/m$^{3}$, the value of reduced rate of pressure drop was shown the highest. Most of all, at high temperature, the value of reduced rate of pressure drop was resulted to 25%. Also the collecting efficiency was shown clearly improved. By the SEM photo analysis, the number of penetrated particles at the Conventional Fabric Filter was approximately two times that of Electrostatically Stimulated Fabric Filter.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.1
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• pp.1999-2004
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• 2020

Background: Although studies on physical motor learning through motor imagery training have been conducted in various fields, studies on its effectiveness are still considered insufficient. Objective: To investigate the effect of motor imagery training and balance training on static balance of asymptomatic adults in their 20s. Design: A quasi-experimental study. Methods: Thirty-six adults in their 20s who passed the tandem stance test were randomized to the motor imagery training group (MIG, n=12), motor imagery with balance training group (MIBG, n=12), and balance training group (BG, n=12). Each group underwent their respective interventions three times a week for four weeks, and changes in static balance were analyzed using multivariate analysis of variance. Results: Trace length was significantly lower in the MIBG than in the MIG and BG (P<.05), and a significant reduction in trace length in the MIBG was observed after the intervention as compared to the baseline (P<.05). Furthermore, a significantly lower velocity was observed in the MIBG than in the MIG and BG (P<.05), and a significant reduction of velocity in the MIBG was more observed after the intervention compared to the baseline (P<.05). Conclusion: These results suggest that motor imagery training enhance static balance in healthy college students.

• Journal of Environmental Science International
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• v.16 no.4
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• pp.449-458
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• 2007

Research results for the pressure drop variance depending on operation conditions such as change of inlet concentration, pulse interval, and face velocity, etc., in a pulse air jet-type bag filter show that while at $3kg/cm^2$ whose pulse pressure is low, it is good to make an pulse interval longer in order to form the first layer, it may not be applicable to industry because of a rapid increase in pressure. In addition, the change of inlet concentration contributes more to the increase of pressure drop than the pulse interval does. In order to reduce operation costs by minimizing filter drag of a filter bag at pulse pressure $5kg/cm^2$, the dust concentration should be minimized, and when the inlet dust loading is a lower concentration, the pulse interval in the operation should be less than 70 sec, but when inlet dust loading is a higher concentration, the pulse interval should be below 30 sec. In particular, in the case that inlet dust loading is a higher concentration, a high-pressure distribution is observed regardless of pulse pressure. This is because dust is accumulated continuously in the filter bag and makes it thicker as filtration time increases, and thus the pulse interval should be set to below 30 sec. If the equipment is operated at 1m/min of face velocity, while pressure drop is low, the bag filter becomes larger and thus, its economics are very low due to a large initial investment. Therefore, a face velocity of around 1.5 m/min is considered to be the optimal operation condition. At 1.5 m/min considered to be the most economical face velocity, if the pulse interval increases, since the amount of variation in filter drag is large, depending on the amount of inlet dust loading, the operation may be possible at a lower concentration when the pulse interval is 70 sec. However, for a higher concentration, either face velocity or pulse interval should be reduced.