• Physical Therapy Korea
• /
• v.9 no.3
• /
• pp.11-21
• /
• 2002

The purpose of this study was to find the effect of rear foot wedge angle on peak plantar pressures on the forefoot during walking. Twenty normal healthy subjects (10 female, 10 male) were recruited. Peak plantar pressure was measured using pressure distribution platforms (MatScan system) in medial forefoot (under the first, second metatarsal head) and lateral forefoot (under the third, fourth, fifth metatarsal head). The subjects walked at the comfortable velocity under seven conditions; bare footed, $5^{\circ}$, $10^{\circ}$ and $15^{\circ}$ wedges under the medial and lateral sides of the hindfoot. The three averaged peak plantar pressures were collected at each condition at stance and toe off phases. The results showed that a significant increase in lateral forefoot plantar peak pressure investigated in the medial wedge and a significant decrease in lateral forefoot plantar peak pressure investigated in lateral wedge at stance phase (p<.05). These results suggest that rear foot wedge may be useful to modify the peak plantar pressure on the forefoot.

• Journal of Korean Foot and Ankle Society
• /
• v.12 no.1
• /
• pp.41-46
• /
• 2008

Purpose: This study was designed to evaluate characteristics of foot pressure distribution with or without partial prosthetic foot in transmetatarsal amputee. Materials and Methods: The subjects were 9 transmetatarsal amputees. Foot pressures were measured at hallux, the $1^{st}-5^{th}$ metatarsal head (MTH), mid-foot, condyle area by F-scan system in amputated or contralateral foot during active walking. Results: In amputated foot, mean peak pressure was greatest in midfoot without prosthetic foot but it was greatest in hindfoot with prosthetic foot. In unaffected foot, although mean peak pressure was higher in hallux, and $1-5^{th}$ MTH compared to amputated foot, it was greatest in hind foot both with and without prosthetic foot. However, in unaffected foot, mean peak pressure significantly decreased in hallux and $5^{th}$ MTH after wearing the prosthetic foot. There was a significant difference in mean peak pressure in hallux and $5^{th}$ MTH between amputated and unaffected foot after wearing prosthetic foot. However, other region had no significant difference with or without prosthetic foot between feet. Conclusions: The use of partial prosthetic foot tends to shift weight bearing from the heel area to forefoot and could significantly reduce hind foot peak pressure and redistributed to peak pressure. The partial prosthetic foot can also offer the peak pressure to reduction both amputated foot and unaffected foot and help to toe off during walking.

• Proceedings of the KSME Conference
• /
• 2001.11b
• /
• pp.432-437
• /
• 2001

A computational work of the impulse wave which is discharged from the open end of a pipe is compared to the Lighthill's aeroacoustics theory. The second-order total variation diminishing(TVD) scheme is employed to solve the axisymmetric, compressible, unsteady Euler equations. The relationship between the initial compressure wave form and the resulting impulse wave is characterized in terms of the peak pressure. The overpressure, pressure gradient and wavelength of the initial compression wave are changed to investigate the influence of the initial compressure wave form on the peak pressure of impulse wave. The results obtained show that for the initial compression wave of a large wavelength and small pressure gradient the peak pressure of the impulse wave depends upon the wavelength and pressure gradient of compression wave, but for the initial compression wave of a short wavelength and large pressure gradient the peak pressure of the impulse wave is almost constant regardless of the wavelength and pressure gradient of compression wave. The peak pressure of the impulse wave is increased with an increase in the overpressure of the initial compression wave. The results from the numerical analysis are well compared to the results from the aeroacoutics theory with a good agreement.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.12 no.1
• /
• pp.48-56
• /
• 2002

A computational work of the impulse wave which is discharged from the open end of a pipe is compared to the Lighthill\`s aeroacoustics theory. The second-order total variation diminishing(TVD) scheme is employed to solve the axisymmetric, compressible, unsteady Euler equations. The relationship between the initial compressure wave form and the resulting impulse wave is characterized in terms of the peak pressure. The overpressure, pressure gradient and wavelength of the initial compression wave are changed to investigate the influence of the initial compressure wave form on the peak pressure of impulse wave. The results obtained show that for the initial compression wave of a large wavelength and small pressure gradient the peak pressure of the impulse wave depends upon the wavelength and pressure gradient of compression wave, but for the initial compression wave of a short wavelength and large pressure gradient the peak pressure of the impulse wave is almost constant regardless of the wavelength and pressure gradient of compression wave. The peak pressure of the impulse wave is increased with an increase in the overpressure of the initial compression wave. The results from the numerical ana1ysis are well compared to the results from the aeroacoutics theory with a food agreement.

• Journal of ILASS-Korea
• /
• v.21 no.3
• /
• pp.155-161
• /
• 2016

Injected fuel pressure waves of a common rail injector with various current profiles supplied to the injecor were measured using Bosch method. In order to drive the common rail injector, the current in the solenoid should be controlled using what is known as a peak and hold pattern, which consists of a high current level with a short time duration (peak) in the first step and a low current level with a long time duration (hold) in the subsequent step. The current profile can be shaped by swithcing an injector driving power source with the peak and hold waves. The capture, compare and PWM (CCP) pin in the microprocessor was used to generate the combined peak and hold waves. The PWM square wave generated from the CCP pin has a duty ratio of 100% for the peak current and 10% or 30% for the hold pattern. Five patterns of the current profile were generated by combining the peak and hold wave. The common rail pressure is controlled at 75, 100, and 130 MPa. As the fuel rail pressure increases, the variations of the measured fuel injection pressure wave according to the current profiles decrease.

• Journal of the Society of Naval Architects of Korea
• /
• v.47 no.3
• /
• pp.410-420
• /
• 2010

When ships are sailing with large motions in rough waves, the slamming phenomenon occurs and the ships suffer from impulsive pressure loadings. Recently, ships are becoming lager and faster than before and it becomes more possible that the ships experience larger impacts on their bows and sterns. Many researchers have been performing the investigations on slamming experimentally and theoretically for a long time. Most of the research reported in the open literature focused on how to accurately estimate the amplitude of the peak pressure of slamming. According to the results of a recently published work, not only the amplitude of peak pressure but also the width of the peak may play an important role in predicting the extents of damage of impacted structures. The uncertainty of impulsive pressure loadings due to slamming has been indicated by many researchers. However, probabilistic treatments of the impulsive pressure loadings are few. In this study, drop tests were conducted on wedges having dead-rise angles of $0^{\circ}$ and $10^{\circ}$. Not only the amplitude of peak pressure but also the width of peak pressure were measured. Furthermore, the variations of those values are also provided for the probabilistic approach of the slamming problem.

• The Journal of Korean Physical Therapy
• /
• v.30 no.6
• /
• pp.224-228
• /
• 2018

Purpose: The most common cause of plantar ulceration is an excessive plantar pressure in patients with peripheral neuropathy. Foot orthosis and therapeutic footwear have been used to decrease the plantar pressure and prevent the plantar ulceration in in diabetes patients. We investigated whether protective sock with functional insoles reduce plantar pressure while walking in 17 diabetes patients. Methods: An in-shoe measurement device was used to measure the peak plantar pressure while walking. Peak plantar pressure data were collected while walking under two conditions: 1) wearing diabetic sock and 2) wearing the protective sock with functional insoles. Each subject walked 3 times in 10-m corridor under three conditions, and data were collected in 3 steps in the middle of corridor with in right and left feet, respectively. Pared t-test was used to compare the peak plantar pressures in three plantar areas under these two conditions. Results: The protective sock with functional insoles significantly reduced the peak plantar pressure on the lateral rearfoot, but significantly increased the peak plantar pressure on the middle forefoot, and medial midfoot (p<0.05). However, there were not significant in medial and lateral forefoot, lateral midfoot, and medial rearfoot between diabetic sock and the protective sock conditions (p>0.05). Conclusion: The protective sock with functional insoles reduced plantar pressures in the rearfoot and supported the medial longitudinal arch. However, it is necessary to change the position of metatarsal pad in the insole design of forefoot area to prevent diabetic foot ulceration.

• The Journal of the Korea Contents Association
• /
• v.12 no.12
• /
• pp.363-371
• /
• 2012

This research is to know about how $VO_2peak$ effects on Abdominal circumference, Blood lipids and blood presure with diabetes patients. After that, we have reached the final decision. in terms of the patients, there is significant indication that Abdominal circumference and HDL-cholesterol are related to $VO_2peak$. And Non-patients and $VO_2peak$ are related to each other though. $VO_2peak$ of the patients significantly effects on Abdominal circumference. Also, $VO_2peak$ of Nom-patients are same in aspect of Diastolic blood pressure As for Abdominal circumference, $VO_2peak$, High-density lipoprotein (HDL) cholesterol, Triglyceride, blood pressure, they are significantly associated to each other For These reasons, we have suggested that $VO_2peak$ seems to be possible to be handled by monitoring index for dangerous factors. Futhermore, exercise is really regarded as the best way of improving Cardiopulmonary capacity.

• Wind and Structures
• /
• v.23 no.4
• /
• pp.275-300
• /
• 2016

Synchronous multi-pressure measurements were carried out with relatively long time duration for a double-layer reticulated shell roof model in the atmospheric boundary layer wind tunnel. Since the long roof is open at two ends for the storage of coal piles, three different testing cases were considered as the empty roof without coal piles (Case A), half coal piles inside (Case B) and full coal piles inside (Case C). Based on the wind tunnel test results, non-Gaussian time-dependent statistics of net wind pressure on the shell roof were quantified in terms of skewness and kurtosis. It was found that the direct statistical estimation of high-order moments and peak factors is quite sensitive to the duration of wind pressure time-history data. The maximum value of COVs (Coefficients of variations) of high-order moments is up to 1.05 for several measured pressure processes. The Mixture distribution models are proposed for better modeling the distribution of a parent pressure process. With the aid of mixture parent distribution models, the existing translated-peak-process (TPP) method has been revised and improved in the estimation of non-Gaussian peak factors. Finally, non-Gaussian peak factors of wind pressure, particularly for those observed hardening pressure process, were calculated by employing various state-of-the-art methods and compared to the direct statistical analysis of the measured long-duration wind pressure data. The estimated non-Gaussian peak factors for a hardening pressure process at the leading edge of the roof were varying from 3.6229, 3.3693 to 3.3416 corresponding to three different cases of A, B and C.

• Wind and Structures
• /
• v.30 no.3
• /
• pp.219-229
• /
• 2020

Net pressures on roofs and walls of buildings are dependent on the internal and external pressure fluctuations. The variation of internal and external pressures are influenced by the size and location of the openings. The correlation of external and internal pressure influences the net pressures acting on cladding on different parts of the roof and walls. The peak internal and peak external pressures do not occur simultaneously, therefore, a reduction can be applied to the peak internal and external pressures to obtain a peak net pressure for cladding design. A 1:200 scale wind tunnel model study was conducted to determine the correlations of external and internal pressures and effective reduction to net pressures (i.e., net pressure factors, F_C) for roof and wall cladding. The results show that external and internal pressures on the windward roof and wall edges are well correlated. The largest ${\mathcal{C}}_{{\check{p},net}$, highest correlation coefficient and the highest F_C are obtained for different wind directions within 90° ≤ θ ≤ 135°, where the large openings are on the windward wall. The study also gives net pressure factors F_C for areas on the roof and wall cladding for nominally sealed buildings and the buildings with a large windward wall opening. These factors indicate that a 5% to 10% reduction to the action combination factor, K_C specified in AS/NZS 1170.2(2011) is possible for some critical design scenarios.