• Bulletin of the Korean Chemical Society
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• v.15 no.2
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• pp.106-112
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• 1994

Six physical properties (molecular weight, heat capacity, side chain weight, side chain volume, standard entropy and partial molar volume) of amino acids, peptides and their derivatives were examined by molecular modeling techniques. The molecular connectivity index, Wiener distance index and ad hoc descriptor are employed as structural parameters to encode information about branching, size, cyclization, unsaturation, heteroatom content and polarizability. This paper examines the correlation of the molecular modeling techique's parameters and the physicochemical properties of amino acids and their derivatives. As a result, calculated values were in agreement with experimental data in the above six physical properties of amino acids, peptides and their derivatives and the molecular connectivity index was superior to the other indices in fitting the calculated data.

• Journal of Astronomy and Space Sciences
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• v.29 no.3
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• pp.259-267
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• 2012

Polar cap potential has long been considered as an indicator for the amount of energy flowing in the magnetosphere-ionosphere system. Thus, the estimation of polar cap potential is important to understand the physical process of the magnetosphere. To estimate the polar cap potential in the Northern Hemisphere, merging electric field by Kan & Lee (1979) is adopted. Relationships between the PC index and calculated merging electric field ($E^*$) are examined during full-time and storm-time periods separately. For this purpose Dst, AL, and PC indices and solar wind data are utilized during the period from 1996-2003. From this linear relationship, polar cap potential (${\Phi}^*$) is estimated using the formula by Doyle & Burke (1983). The values are represented as $58.1{\pm}26.9$ kV for the full-time period and $123.7{\pm}84.1$ kV for a storm-time period separately. Considering that the average value of polar cap potential of Doyle & Burke (1983) is about 47 kV during moderately quiet intervals with the S3-2 measurements, these results are similar to such. The monthly averaged variation of Dst, AL, and PC indices are then compared. The Dst and AL indices show distinct characteristics with peaks during equinoctial season whereas the average PC index according to the month shows higher values in autumn than in spring. The monthly variations of the linear correlation coefficients between solar wind parameters and geomagnetic indices are also examined. The PC-AL linear correlation coefficient is highest, being 0.82 with peaks during the equinoctial season. As with the AL index, the PC index may also prove useful for predicting the intensity of an auroral substorm. Generally, the linear correlation coefficients are shown low in summer due to conductance differences and other factors. To assess the role of the PC index during the recovery phase of a storm, the relation between the cumulative PC index and the duration is examined. Although the correlation coefficient lowers with the storm size, it is clear that the average correlation coefficient is high. There is a tendency that duration of the recovery phase is longer as the PC index increases.

• Geomechanics and Engineering
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• v.34 no.6
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• pp.697-726
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• 2023

Brittleness as an important property of rock plays a crucial role both in the failure process of intact rock and rock mass response to excavation in engineering geological and geotechnical projects. Generally, rock brittleness indices are calculated from the mechanical properties of rocks such as uniaxial compressive strength, tensile strength and modulus of elasticity. These properties are generally determined from complicated, expensive and time-consuming tests in laboratory. For this reason, in the present research, an attempt has been made to predict the rock brittleness indices from simple, inexpensive, and quick laboratory test results namely dry unit weight, porosity, slake-durability index, P-wave velocity, Schmidt rebound hardness, and point load strength index using multiple linear regression, exponential regression, support vector machine (SVM) with various kernels, generating fuzzy inference system, and regression tree ensemble (RTE) with boosting framework. So, this could be considered as an innovation for the present research. For this purpose, the number of 39 rock samples including five igneous, twenty-six sedimentary, and eight metamorphic were collected from different regions of Iran. Mineralogical, physical and mechanical properties as well as five well known rock brittleness indices (i.e., B₁, B₂, B₃, B₄, and B₅) were measured for the selected rock samples before application of the above-mentioned machine learning techniques. The performance of the developed models was evaluated based on several statistical metrics such as mean square error, relative absolute error, root relative absolute error, determination coefficients, variance account for, mean absolute percentage error and standard deviation of the error. The comparison of the obtained results revealed that among the studied methods, SVM is the most suitable one for predicting B₁, B₂ and B₅, while RTE predicts B₃ and B₄ better than other methods.

• Journal of the Korean Society of Physical Medicine
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• v.14 no.4
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• pp.9-17
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• 2019

PURPOSE: This research was designed to study the correlations between physical activities such as foot sensory impairment, balance and ambulatory abilities, as well as fall risk factors and mental activities such as cognitive performance and depression in order to provide fundamental data for the prevention of falling in the elderly. METHODS: A total of 36 elderly people over the age of 65 years who voluntarily joined the research were selected as subjects. Sensory perception in both feet was measured by using a monofilament in 10 parts with each part given one point. The points for each foot were integrated to analyze the correlations between physical and mental activities indices, and the results were analyzed by using Pearson's correlation coefficient. RESULTS: The results of this research show that the extent to which senses in feet were impaired was correlated to TUG, a functional activity index involved in tranfers, gait, and turning movements, which was correlated to BBS (balance index) as well as MMSE-K and K-GDS (mental activities index). BBS was interrelated to FES-K (physical activities index) and MMSE-K. The muscular strength of the right ankle dorsiflexor had mutual relations with FES-K. CONCLUSION: The results of this research indicate that TUG is widely correlated to foot sensory impairment as well as general physical and mental activities in elderly people. BBS was also shown to be correlated with TUG, FES-K, and MMSE-K. Thus, it might be necessary that TUG and BBS be included as two items in physical and mental check-ups for the elderly, and further studies on correlations using evaluation items for physical and mental activities should lead to the simplification of the evaluation criteria.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.12 no.3
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• pp.83-97
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• 2009

The objects of study is to propose criteria for physical river disturbance assessment and as case study to show the application results for river improvement. For this purpose, the river disturbance assessment method for past disturbance process and the present-day potential natural state of stream is proposed. To assess the disturbance of the Youngcheon River caused by river improvement, One ares of Nam River was selected for the reference reach and two areas of Youngcheon River were selected for the comparison reach. And these reaches were surveyed and analyzed according to applying criteria of the river disturbances assessment. The assessment indices were physical factors as like epifaunal (bottom), embededness, velocity/depth regime, sediment deposition, channel flow status, channel alteration, frequency of riffles, bank stability, vegetative protection and riparian zone etc. The results showed that physical river environment in Youngcheon River area was disturbed by artificial revetment and bed excavation, consequently this disturbance give rise to impact of ecosystem in river. Hereafter, the criteria for river disturbance assessment are needed to consider various river characters as bed materials and bed slop etc.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1B
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• pp.71-78
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• 2012

The habitat suitability is an important factor to estimate the distribution and size of the physical habitat in river. This suitability is also a key factor to decide the ecological flow discharge for the fish. For the ecological analysis in river, accurate values of habitat suitability index for various fishes are necessary. In general, fish habitat is affected by the physical factor of the flow depth and velocity as well as the chemical and biological factors of nutrient and attached algae. Thus, the condition of the fish habitat is expected to be changed with each watershed and tributary. In this study, the habitat suitability indices for fishes were proposed by using the field monitoring data in the rivers of the Han and Geum river watersheds. The proposed indices for three fishes are compared: Zacco platypus, Zacco temminckii, and Coreoleuciscus splendidus. The results show that Zacco platypus has a similar distribution of habitat suitability index in two watersheds. Zacco temminckii and Coreoleuciscus splendidus, however, have different distributions with watersheds. Also, for Zacco platypus, the developed indices at three tributaries of the Han river are compared: Cheng-mi stream, Dal stream, and Hong-cheon stream. The comparision shows that the index in the Cheng-mi stream is different with those in the other rivers. This is expected to be because of a high nutrient concentration at the Cheong-mi stream.

• Journal of The Korean Astronomical Society
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• v.22 no.1
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• pp.31-41
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• 1989

Luminosity profile of the late type spiral galaxy NGC 2403 was obtained using the PDS scan of the plate. Some physical parameters (scale length, total magnitude, central brightness, disk to bulge ratio and concentric indices) were calculated from the brightness distribution. Total mass and the mass to luminosity ratio were estimated from the fitting of various mass models.

• Physical Therapy Korea
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• v.24 no.4
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• pp.20-28
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• 2017

Background: Rasch analysis has the advantage of placing both the items and the person along a single ratio scale and calibrates person ability and item difficulty onto an interval scale by logits. Therefore, Rasch analysis has been recommended as a better method for evaluating functional outcome questionnaires than traditional analyses. Objects: The aim of current study was to investigate item fit, item difficulty, rating scale, and separation index of the Korean version of the Fullerton Advanced Balance (KFAB) scale using Rasch analysis. Methods: In total, 93 patients with stroke (male=58, female=35) participated in this study. To investigate the item fit, difficulty, rating scale, and separation index of the KFAB scale, Rasch analysis was completed by the Winsteps software program. Results: In this study, all items of the KFAB scale were included in the Rasch model. The most difficult item was 'standing with feet together and eyes closed', and the easiest item was 'two-footed jump'. The rating scale was a 4-point scale instead of the original 5-point scale. Person and item separation indices showed high values that can identify a person with a wide range of balance ability. Conclusion: The KFAB scale appears to be a reliable and valid tool to assess balance function in patients with stroke. Furthermore, the scale was found to discriminate among stroke patients of varying balance abilities.

• Journal of Korean Physical Therapy Science
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• v.18 no.3
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• pp.93-99
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• 2011

Purpose : In order to investigate the effects of balance training on patients with degenerative arthritis. Methods : 30 participants aged 60 or older participated in balance training for an 8-week period. The effects of the balance training were measured by the visual analog scale(VAS) and static and dynamic balancing. The following are the results of the study. Results : There were no statistically significant differences in measurements of pain when control group participants were at rest and while walking as measured by VAS, but there were statistically significant reductions for the experiment group. Within the control group, there were no statistically significant differences between pretest and posttest results for opened and closed-eye static balance index and visual dynamic balance index. However, within the experiment group, there were statistically significant differences between pretest and posttest results for opened and closed-eye static and dynamic balance indices. Conclusion : The results above provide evidence that balance training effects pain and balance of patients with osteoarthritis and aids in functional movement.

• PNF and Movement
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• v.19 no.1
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• pp.67-77
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• 2021

Purpose: The purpose of the study was to identify the effects of proprioceptive neuromuscular facilitation (PNF) training and robot rehabilitation training on trunk stability and standing balance in individuals with chronic stroke. Methods: There were 30 patients with chronic stroke, divided into two groups: 15 subjects who received PNF and robot training (the experimental group) and 15 subjects who received standard conservative training (the control group), that participated. The experimental group received treatment for 60 min: 30 min of conventional physical therapy, 15 min of PNF training, and 15 min of robot training. The control group received conventional physical therapy for 60 min. Trunk stabilization (trunk impairment scale) and standing balance (center of pressure, limit of stability, modified functional reach test, and Berg balance scale) were measured before and after intervention. Results: Within each group, both the experimental and control groups significantly improved after the intervention in all tests; however, the experimental group showed greater improvement in scores on the trunk impairment scale, the center of pressure, the limit of stability, the modified functional reach test, and the Berg balance scale. Conclusion: The study verified that PNF training and robot training had a positive influence on trunk stability and standing balance indices in patients with chronic stroke.