• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.3
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• pp.119-127
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• 2018

A test stand for an altitude test of reciprocating engine was designed, manufactured and validated by preliminary tests and simple calculations. The test stand was designed to interface with the altitude turbo-shaft engine test facility of Korea Aerospace Research Institute. Many limiting conditions for altitude test of reciprocating engine were assumed and the test stand was developed to satisfy these limitations. The test stand design was focused especially on the altitude, Mach number and fuel temperature control for reciprocating engine altitude tests with smaller air and fuel flow than those of turbo shaft engines.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.3
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• pp.53-60
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• 2003

A test stand was developed to measure static performance of a reciprocating engine on the ground, related to the small aircraft being developed by KARI. The test stand consists of an apparatus to install and operate a pusher-type propulsion system and a data acquisition system to process many performance parameters including engine torque and propeller thrust as well as monitoring of the engine operations. First, the performance data from the basic operation tests were compared with the original engine data so the capacity of the test stand was verified. Engine performance tests were carried out with various test conditions through three stages, and it was measured and analyzed that the manifold pressure, the torque, and the back pressure of the engine, and the static thrust of the propeller.

• Journal of Korean Society of Forest Science
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• v.88 no.4
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• pp.446-453
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• 1999

In this study, the effects of stand planting density on parameters of stand height and basal area growth models were investigated. We used the Korf equation as the base model in estimating the parameters of the growth models for cryptomeria plantation forest stands. Then, in order to investigate the effects of the change in plantation density on the parameter estimates, the "extra sums of square" principle, which provided a reasonable statistical procedure for a performance test, was used. The results of the test coincide with the understandings that stand height growth is not affected significantly by the planting density and the growth curves of stand basal area approaches a common asymptote regardless of the stand density for a given site. However, the shapes of the basal area growth curves were affected significantly by the planting density. Based on the results of the test, we developed a basal area growth model to account for the effects of initial planting density in cryptomeria plantation forest stands.

• PNF and Movement
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• v.20 no.2
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• pp.157-166
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• 2022

Purpose: The aim of this research was to investigate the effects of self-sit-to-stand training on balance ability and sit-to-stand ability in hemiplegic stroke patients using a multisensory feedback device. Methods: A total of 19 stroke patients participated in this study, and they were divided into two groups: 10 underwent self-sit-to-stand training using a multisensory feedback device, and 9 underwent sit-to-stand training with a physical therapist. In both groups, sit-to-stand training was performed for 30 min, 3 times a week, for 6 weeks. The subjects also underwent physical therapy twice a day for 30 min, 10 times a week, for a total of 60 sessions. Balance ability was evaluated using the AFA-50 and Berg Balance Scale. Sit-to-stand ability was evaluated using the five times sit-to-stand test. Results: Sway length, pressure, and total pressure all significantly increased in both groups, and there was no difference between the two groups. The Berg Balance Scale results showed that balance ability significantly increased in both groups, and there was no difference between the two groups. The five times sit-to-stand test results showed that sit-to-stand ability significantly increased in both groups, and there was no difference between the two groups. It was found that the self-sit-to-stand training using a multisensory feedback device had a positive effect on balance control and sit-to-stand ability. When the two groups were compared, no difference in balance ability or sit-to-stand ability was observed. Conclusion: The findings of this study indicate that self-sit-to-stand training using a multisensory feedback device is as effective as sit-to-stand training with a physical therapist. Hence, self-sit-to-stand training using a multisensory feedback device could be an effective home-based exercise protocol for hemiplegic stroke patients to improve their balance and sit-to-stand abilities.

• PNF and Movement
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• v.15 no.1
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• pp.77-84
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• 2017

Purpose: This study aimed to investigate the effect of visual feedback training-for gradual weight shift in sit-to-stand training-on the balance and walking abilities of chronic hemiplegia patients. Methods: Twenty patients with chronic hemiplegia volunteered to participate in this study. The experimental group received visual feedback for gradual weight shift in the sit-to-stand training, while the contrast group followed the standard process for the sit-to-stand training. The evaluation of the balance and walking ability was conducted with the functional reach test (FRT), Berg balance scale (BBS), five time sit-to-stand (FTSTS) test, timed up and go (TUG) test, 10 m walk test (10MWT), balancia, activities-specific balance confidence (ABC) scale, and falls efficacy scale (FES). Results: In the results before and after intervention, there was a significant difference in TUG, 10MWT, ABC, and FES in the visual feedback training group (p < 0.05). In the control group, there was a significant difference in the 10MWT and ABC (p < 0.05). Also, in the evaluation of the postural fluctuations, the control group data showed a significant increase in Covar. The visual feedback group showed a significant difference in the W average. Conclusion: The visual feedback training group showed some improvement in terms balance and walking ability and on the ABC scale and FES. Therefore, if the diagonal progressive weight bearing exercise is combined with the various patterns and basic principles of PNF, it may be a more efficient intervention method.

• Journal of the Korean Society of Physical Medicine
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• v.8 no.4
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• pp.549-558
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• 2013

PURPOSE: This study is designed as a retrospective study, and identified the clinical usability of Sit to Stand (STS) test for predicting of fall incidence in stroke patients who experienced a fall within 1 year. METHODS: Between July 2011 and November 2012, 69 inpatients with stroke in K rehabilitation hospital were participated under voluntarily signing the informed consent form. STS test and 10m walk test (10MWT) were used to assess the muscle strength of lower-extremity and walking velocity, respectively. Also, we tested dynamic balance and motor function of lower-extremity in affected-side using with the Berg balance scale (BBS) and the Fugl-Meyer assessment of lower extremity (FM-L/E). METHODS: There were significant differences between subjects with fall-experienced group and without subjects without fall-experienced group in STS test, 10MWT, BBS scores and FM-L/E. STS test significantly showed a negative correlation between 10MWT (r=-.657), BBS (r=-.512), and FM-L/E (r=-.563). And, 10MWT have a influence on the performance of STS test (the capacity of explanation = 20%). The cut-off value of STS performance predicting falls experience is ${\geq}14.36$ seconds (sensitivity=76%; specificity=79%, area under curve=.785). According to logistic regression analysis of falls experience, subjects ${\geq}14.36$ s showed that 4.164 times (odd ratio) increased in falls than subjects < 14.36 s in STS test. CONCLUSION: This study demonstrated that STS test may be a useful tool predicting and measuring falls in patients with stroke. Further study will be needed to elucidate the kinematic analysis of STS test and the relationship between physical activity level and falls in stroke patients.

• The Korean Journal of Ecology
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• v.23 no.6
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• pp.435-438
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• 2000

Diameter distributions describe forest stand structure information. Prediction equations for percentiles of diameter distribution and parameter recovery procedures for the Weibull distribution function based on four percentile equations were applied to develop prediction system of even-aged slash pine stand structure development in terms of the number of stems per diameter class changes. Four percentiles of the cumulative diameter distribution were predicted as a function of stand characteristics. The predicted diameter distributions were tested against the observed diameter distributions using the Kolmogorov-Smirnov two sample test at the ${\alpha}$=0.05 level. Statistically, no significant differences were detected based on the data from 236 evaluation data sets. This stand level diameter distribution prediction system will be useful in slash pine stand structure modeling and in updating forest inventories for the long-term forest management planning.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.360-366
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• 2016

The Propulsion Test Facilities for the development of Korea Space Launch Vehicle-II are being built, some test facilities are completed and various combustion tests are running. The Propulsion Test Facilities consists test-stand, which carries out tests for engine development model, and various sub-systems and vessels containing LOX and Jet A-1 as propellant. There are always risks of fire and explosion at the test-stand since engine development model is conducted at test-stand with real combustion test with very high pressure, mixed propellant and high energy. In this paper, in order to establish the consequence analysis and risk reduction measures in the Propulsion Test Facilities, followings are considered. 1) a propellant leak accident scenario is assumed in test-stand. 2) TNT equivalent model equation based on blast wave of the explosion was used to analyze blast overpressure and impacts. Also, technical, systematic and managemental measure is described to ensure risk reduction for propulsion test facility.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.613-621
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• 2014

This study was conducted to estimate the changes of stand diversity before and after applying three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. Data were collected in the natural deciduous forests in Pyungchang of Gangwon Province, Korea. Nine permanent sampling plots of 0.09 ha were established in the forests and the each of silvicultural treatments was applied to three sampling plots, respectively. Some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after the silvicultural treatments. In this study, two different indices related to each of stand diversity indices such as contagion, DBH-difference, height-difference, and mingling were estimated and compared to analyze the differences of stand diversity among the stands before and after silvicultural treatments. As a result, total eight stand diversity indices were used to analyze the differences among structures of stands managed by three different silvicultural treatments. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand diversity among the stands. The results revealed that stand structures seem to be improved after applying the silvicultural treatments. There are significant differences in the stand diversity indices between before and after silvicultural treatments for each stand. According to the evaluation of stand diversity indices, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments.

• Journal of Korean Society of Forest Science
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• v.101 no.2
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• pp.297-304
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• 2012

The objective of this study was to estimate the changes of stand structure before and after applying the three different silvicultural treatments such as selection cutting system, two-storied system, and shelterwood system. This study has been conducted in the natural deciduous forests in Pyungchang of Gangwon Province, Korea. Three permanent sampling plots of 0.09 ha were established in the forests and the three silvicultural treatments were applied in 2008. For this study, some tree variables were measured in each stand before and after the silvicultural treatments were applied. With these data, stand attributes were estimated in each stand before and after the silvicultural treatments. In this study, four stand structure indices were used to analyze the differences among structures of stands managed by three different silvicultural treatments. Contagion index, DBH-difference index, height-difference index, and mingling index were estimated and compared to analyze the differences of stand structures among the stands before and after silvicultural treatments. Duncan's multiple range test and t-test were then employed to statistically analyze the difference of stand structure among the stands. The results revealed that all of the stand structure indices seem to be increased after applying the silvicultural treatments. There are significant differences in the stand structure indices between before and after silvicultural treatments for each stand. According to the evaluation of stand structure indices, it was confirmed that spatial structure of the stands was improved by applying the silvicultural treatments. For attaining the specific goal of each stand types acquired by different silvicultural treatments, the frequencies and amounts of additional practices should be decided based on the changes of stand structure as time passed.