• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.11a
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• pp.363-364
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• 2008

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.135-138
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• 2006

We developed an engine system design program by balancing the pressure-mass-power relation which can be acquired from each component's specification. In gas generator type open-cycle rocket engine system it is possible to distinguish the variables into two categories, which are input variables and requirement variables. We define 11 design variables corresponding to the 11 balance equations as functions of pressure, mass and power of target engine system. We solved these equations by Newton method. As an example we designed gas generator cycle engine system and finally we could conclude that this developed program is well suited to the engine system design.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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• pp.561-568
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• 2014

Injection molding industries realize the necessity of developing family molds to improve competitiveness. One of the primary causes of manufacturing defective products is the imbalance of flow in a family mold. In this study, the family mold of a shelf for refrigerators is analyzed by using CAE software. First, the flow balance, clamping force, and injection pressure are analyzed for different gate diameters of two cavities. Second, the flow balance, clamping force, and injection pressure are improved when the two gate valves are open at different times. Finally, the results of filling analysis are compared with the test injection product.

• Journal of The Korean Society of Integrative Medicine
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• v.11 no.3
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• pp.127-135
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• 2023

Purpose : This study was performed to evaluate the effects of magnetic therapy (MT) on pain threshold, blood flow, and balance in patients with knee osteoarthritis. Methods : A single-blind, randomized controlled trial (RCT) was conducted with 30 patient with knee osteoarthritis. They were randomly allocated 2 groups; magnetic therapy group (MTG; n=15) and placebo magnetic therapy group (PG; n=15). The MTG group received 30 minutes magnetic therapy and 20 minute conservative physical therapy (Hotpack, ICT), magnetic therapy was conducted in magnetic therapy device (OM-100, NUGA, Korea). In the placebo magnetic group received 30 minutes placebo magnetic therapy and 20 minute conservative physical therapy. Each group performed 50 minutes a day 3 times a week for 8 weeks. The primary outcome pressure pain threshold test, blood flow, balance ability were measured by a pressure threshold meter (Commander algometer, JTECH medical, USA), laser dofler image (Moor LDI2-IR, Moor instruments, USA), balance measurement system (BioRescue, Marseille, France). The measurement were performed before and after the 8 weeks intervention period. Results : Both groups demonstrated significant improvement of outcome in pain threshold, blood flow, and balance ability during intervention period. magnetic therapy group revealed significant differences in pain threshold, blood flow, and balance as compared to the placebo magnetic therapy group groups (p<.05). Our results showed that magnetic therapy was more effective than placebo therapy on pain threshold, blood flow, and balance in patients with knee osteoarthritis. Conclusion : Our findings indicate that magnetic therapy can improve pain threshold, blood flow, and Balance, highlight the benefits of magnetic therapy. This study will be able to be used as an intervention data for recovering pain threshold, blood flow, and balance in patients with knee osteoarthritis.

• Journal of Fashion Business
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• v.28 no.1
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• pp.83-97
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• 2024

A plantar pressure mat with visual notifications was developed to confirm whether individuals can effectively balance themselves and correct imbalances. The sensor-embedded mat was made with a commercial yoga mat, and was tested on seven working women in their 30s to determine plantar pressure distribution when standing and squatting, and if they could recognize and correct imbalances with visual feedback. The study found that visual notifications significantly changed the plantar pressure ratio of the forefoot and hindfoot, as well as the left and right foot plantar pressure ratio. Without notifications, the center of gravity was more concentrated in the rear foot than the forefoot in both standing and squatting positions. Visual notifications showed that the center of gravity, which was largely focused on the rear foot, was distributed to the forefoot, resulting in a more evenly distributed center of gravity throughout the sole. For the change in left and right plantar pressure, the weight that was largely loaded on the left side was distributed to the right foot through the visual notification mat, confirming a more balanced plantar pressure.

• Physical Therapy Korea
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• v.28 no.2
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• pp.154-160
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• 2021

Background: Theoretically, balance is affected by the height of center of mass (COM) during quiet standing. However, no one examined this in humans with variables derived from the center of pressure (COP). Objects: We have conducted balance experiment to measure COP data during quiet standing, in order to examine how the COP measures were affected by the height of COM, vision, floor conditions, and gender. Methods: Twenty individuals stood still with feet together and arms at sides for 30 seconds on a force plate. Trials were acquired with three COM heights: 1% increased or decreased, and not changed, with two vision conditions: eyes closed (EC) and eyes open (EO), and with two floor conditions: unstable (foam pad) and stable (force plate) floor. Outcome variables included the mean distance, root mean square distance, total excursion, mean velocity, and 95% confidence circle area. Results: All outcome variables were associated with the COM height (p < 0.0005), vision (p < 0.0005), and floor condition (p < 0.003). The mean velocity and 95% confidence circle area were 5.7% and 21.8% greater, respectively, in raised COM than in lowered COM (24.6 versus 23.2 mm/s; 1,013.4 versus 832.3 mm²). However, there were no interactions between the COM height and vision condition (p > 0.096), and between the COM height and floor condition (p > 0.183) for all outcome variables. Furthermore, there was no gender difference in all outcome variables (p > 0.186). Conclusion: Balance was affected by the change of COM height induced by a weight belt in human. However, the effect was not affected by vision or floor condition. Our results should inform the design of balance exercise program to improve the outcome of the balance training.

• Journal of the Korean Vacuum Society
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• v.22 no.5
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• pp.231-237
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• 2013

New method of volume measurement for reference weights of a pressure balance using a gas pycnometer is proposed. The result of volume measurement of proposed method shows the uncertainties of approximately 0.2% at the level of confidence of 95% for reference weights in the ranges of 1 kg, 2 kg, and 5 kg. This measuring system consists of a sample chamber, an expansion chamber, a precision pressure gage, a precison thermometer, a vacuum pump, and helium as a medium gas. The measurement principle of this proposed method is based on Boyle's law. This method will contribute a reliability of the volume measurements of reference weights for a pressure balance to the national measurement standard.

• Journal of Nutrition and Health
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• v.24 no.1
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• pp.40-47
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• 1991

To investigate a possible effect of pectinate(apple and carrot) and alginate (tangle or green laver) on blood pressure and sodium retention, male spontaneous hypertensive rats (SHR) were assigned to 5 different experimental groups and fed diets containing 5% dietary fiber and 1% NaCl for 3 weeks. Dietary fibers were provided from one of the followings : cellulose, freeze dried apple, carrot, tangle(Undardia pinnatifda) or green laver(Monostroma nitidium). Fecal sodium excretion did not change significantly among the groups, however, urinary sodium excretion was increased in groups fed either carrot. tangle or green laver compared to group fed cellulose. Sodium balance was also negative in groups fed either carrot, tangle or green laver. most effectively in green laver group. Blood pressure of groups fed apple. carrot. tangle or green laver were decreased, especially those of group fed tangle, compared to those of group fed cellulose. Dietary fiber containing alginate. such as tangle and green laver, might have cellular binding capacity to sodium so that increased urinary sodium excretion and decreased blood pressure occur.

• Journal of Biomedical Engineering Research
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• v.9 no.2
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• pp.233-238
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• 1988

Human body sways continuously to maintain balance during upright stance. A computer-aided instrumentation system using a force platform has been developed to investigate the body balance. The Kistler force platform and amplifiers were only used to obtain the precise measurements, and the data acquisition and analysis software operating on an IBM PC with A/D converter was developed. This study presents methods for the display of platform center of pressure data on stability study. This system can be used as a tool in evaluating the man's ability to balance and disorders of the nervous system.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.22 no.1
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• pp.65-70
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• 2016

Background: To determine the correlation Between forward head posture and plantar pressor in a McKenzie Exercise. Methods: This study had a cross-sectional design. There are included 20 participants with forward head posture. We measured the craniovertebral angle (CVA), cranial rotation angle (CRA) by image obtained digital camera and the plantar pressure, static balance using Gait Analyzer each before and after McKenzie Exercise. Results: There was negative correlation between CVA and CRA (p<.05). There was negative correlation between CVA and fore foot(p<.05). There was positive correlation between CRA and both fore foot (p<.05). There was negative correlation between CVA and static balance(p<.05). There was positive correlation between CRA and static balance (p<.05). Conclusions: There is a correlation between the change a mount of forward head position and plantar pressure in the McKenzie Exercise.