• Physical Therapy Korea
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• v.9 no.2
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• pp.1-17
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• 2002

The purpose of this study was to identify the differences of the static and the dynamic balance reactions in the flexion syndrome (FS) and the extension syndrome (ES) group of the patients with chronic lowback pain (LBP) and healthy subjects. Twenty subjects were included in each group. By using EquiTest 5.02, the static balance was measured by the equilibrium score and the strategy score of sensory organization test (SOT), while the dynamic balance was measured by the latency of motor control test (MCT) and the sway energy of adaptation test (ADT). Oswestry Disability Index (OSI) was used to measure level of the disability in patients with chronic LBP. The equilibrium scores, the strategies of SOT, and thelatencies of MCT of three groups were compared with one way ANOVA, while the sway energy of ADT was compared with repeated measures one way ANOVA. The results of this study showed that the equilibrium scores and the strategy scores of SOT were significantly lower in patients with chronic LBP than in healthy subjects. The equilibrium scores and the strategy scores of SOT were significantly differences between the FS and ES groups in condition 5 (support surface was sway-referenced and visual information waseliminated by eye closure), and 6 (support surface was sway-referenced and visual information was altered by sway-referencing). The FS group showed delayed average reaction time at large posterior translation, however, the ES group showed delayed average reaction time at large anterior translation, Even though the sway energy of the patients with chronic LBP were greater than that of healthy subjects during the toe down (plantar flexion rotation), the values between the FS and ES groups didn't show any significant difference. The disability level showed highly correlation with the equilibrium score of the condition 5. As the results, the FS and ES groups divided by the their symptoms and signs in patients with chronic LBP showed different balance reaction. Therefore, more accurate evaluation and balance treatments are needed to focus on their symptoms and signs in patients with chronic LBP.

• Journal of computational fluids engineering
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• v.14 no.1
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• pp.24-34
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• 2009

The equilibrium molecular-dynamic simulations have been performed to estimate the properties of the three kinds of fluids confined between two plates that are separated by 1.086 nm; included in the statical properties are the density distribution and the static structure, and the autocorrelation velocity function in the dynamic property. Three kinds of fluids considered in this study are the Lennard-Jones fluid, water and aqueous sodium-chloride solution. The water molecules are modeled by using the SPC/E model and the ions by the charged Lennard-Jones particle model. To treat the water molecules, we combined the quaternion coordinates with Euler angles. We also proposed a plausible algorithm to assign the initial position and direction of molecules. The influence of polarization of water molecules as well as the presence of ions in the solution on the properties will be addressed in this study. In addition, we performed the non-equilibrium molecular-dynamic simulation to compute the flow velocity for the case with the gravitational force acting on molecules.

• Journal of the Korean Chemical Society
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• v.50 no.3
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• pp.247-255
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• 2006

The purpose of this study was to investigate the correlation between concepts on chemical reaction rates and concepts on chemical equilibrium in high school students. The subjects of the investigation consisted of 120 third grade students attending high school in K city of Kyunggi province. For this study, questionnaire relevant to the subject of chemical reaction rates and chemical equilibrium was developed and the answers were analyzed. As a result of the study, a large percentage of high school students answered questions on reaction rates correctly, but only a small percentage of the students could give explanations. Many high school students answered questions on the rates of forward reactions correctly, but not the questions on the rates of reverse reactions. For the concepts on chemical equilibrium, many high school students gave correct answers when faced with equilibrium questions that only required the understanding of one side of the reaction. But the students could not answer the questions requiring understanding of both forward and reverse reactions as well. Overall, there was a little high correlation between concepts on chemical reaction rates and concepts on chemical equilibrium in high school students. Especially, high school students with little understanding of reverse reaction rates did not understand that chemical equilibrium is a dynamic equilibrium. Also, high school students with little understanding of the collision mechanism regarding chemical reaction rates did not understand the effect of concentration and catalyst factors on chemical equilibrium. And the correlation between concepts on chemical reaction rates and concepts on chemical equilibrium related to concentration and catalyst factors was low. In conclusion, the formation of scientific concepts on chemical reactions rates can decrease misconceptions on chemical equilibrium. Also the teaching-learning method limited to one side of a reaction can cause difficulty in forming the concepts on chemical dynamic equilibrium. Therefore, the development of a teaching-learning method which covers both the forward and reverse reactions can be effective in helping students form the concepts on chemical equilibrium.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.04a
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• pp.292-299
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• 1999

In order to investigate dynamic behaviors of marine cables under wave and earthquake forces a geometric nonlinear. F, E formulation of marine cables is presented and tangent stiffness and mass matrices for the isoparametric cable element are derived, The initial equilibrium state of cables subjected to self -weights and current forces is determined and free vibration and dynamic nonlinear analysis of cable structures under additional environmental loads are performed based on the initial configuration Challenging examples are presented and discussed in order to demonstrate the feasibility of the present finite element method and investigate dynamic nonlinear behaviors of marine cables.

• Physical Therapy Korea
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• v.25 no.2
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• pp.30-43
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• 2018

Background: Hemispatial neglect is defined as the failure to attend, report, respond, or orient toward meaningful stimuli provided in the contralateral side of a brain lesion. Objects: This study was conducted to find out the effect of dynamic trunk equilibirum exercise for stroke patients with hemi-spatial neglect. Methods: This study included 21 stroke subjects, randomly assigned to either the experimental group or the control group. The exercise program consisted of 5 sessions of 20 minutes per week during 4 weeks. The line-bisection test, the Albert test, the balance function score, the Berg balance scale, the postural assessment scale for stroke and the modified Barthel index were measured before and after training. All data were analyzed using SPSS 12.0 for Windows. Between-group and within-group comparison was analyzed by using Independent t-test and Paired t-test respectively. Results: The results of study were as follows: There were significant differences between before and after intervention in both group (p<.05). There were significant differences in the line-bisection test, Albert test, balance function score, Berg balance scale, postural assessment scale for stroke and modified Barthel index between the experimental group and the control group (p<.05). Conclusion: Dynamic trunk equilibrium exercise had a positive effect on patients' neglect, balance ability and activities of daily living. Further studies are required to generalize the results of this study.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.465-470
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• 2001

This paper presents an algorithm which seeks steady-state equilibrium positions of constrained multibody systems driven by constant generalized speeds. Since the relative coordinates are employed, the constraint equations at cut joints are incorporated into the formulation. The proposed algorithm leads to nonlinear equations that need to be solved iteratively. This algorithm should satisfy both types of conditions: the force equilibrium equations and the kinematic constraint equations. To verify the effectiveness of the proposed algorithm, two numerical examples are solved and the results are compared with those of a commercial program. This method, compared to the conventional method of using dynamic analysis, has the advantage of computational efficiency and stability.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.493-502
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• 2010

In this paper, the ionization characteristics of noble gases are studied numerically behind strong shock waves. As a first step, the equilibrium ionization mechanism of noble gases is modeled in wide ranges of temperature and pressure. As a next step the equilibrium ionization model is coupled with fluid dynamic equations to analyze the local thermodynamic equilibrium(LTE) ionization process at high temperature and pressure conditions behind the strong imploding shock waves. The ionization characteristics of xenon gas is studied in a wide range of test conditions with thermal radiation effects. Hence, the results give optimal conditions of maximum ionization and radiation behind the imploding shock waves.

• Journal of Korean Association for Spatial Structures
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• v.20 no.2
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• pp.59-68
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• 2020

In this paper, the dynamic snapping of the 3-free-nodes spatial truss model was studied. A governing equation was derived considering geometric nonlinearity, and a model with various conditions was analyzed using the fourth order Runge-Kutta method. The dynamic buckling phenomenon was observed in consideration of sensitive changes to the force mode and the initial condition. In addition, the critical load level was analyzed. According to the results of the study, the level of critical buckling load elevated when the shape parameter was high. Parallelly, the same result was caused by the damping term. The sensitive asymmetrical changes showed complex orbits in the phase space, and the critical load level was also becoming lowly. In addition, as the value of damping constant was high, the level of critical load also increases. In particular, the larger the damping constant, the faster it converges to the equilibrium point, and the occurrence of snapping was suppressed.

• Research in Community and Public Health Nursing
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• v.20 no.4
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• pp.391-402
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• 2009

Purpose: This study was to show the effects of a Physical activity promotion program with tele-coaching on physical fitness (grip strength, static and dynamic equilibrium) and quality of life in the frail elderly. Methods: Data were collected from May 30 to October 19, 2008. The subjects were divided into 2 groups, an experimental group (n=27) and a control group (n=26). The experimental group participated in the Physical activity promotion program, and the control group did not participate in any Physical activity promotion program. Results: The results of this study supported the hypothesis that "the experimental group will have higher physical fitness (right grip strength, left grip strength and static equilibrium except dynamic equilibrium) and quality of life than the control group." Conclusion: Physical activity promotion programs with tele-coaching are strongly recommended as health promotion for the frail elderly.

• Structural Engineering and Mechanics
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• v.60 no.1
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• pp.111-130
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• 2016

Two new elements with six degrees of freedom are proposed by applying the equilibrium conditions and strain-displacement equations. The first element is formulated for the infinite ratio of beam radius to thickness. In the second one, theory of the thick beam is used. Advantage of these elements is that by utilizing only one element, the exact solution will be obtained. Due to incorporating equilibrium conditions in the presented formulations, both proposed elements gave the precise internal forces. By solving some numerical tests, the high performance of the recommended formulations and also, interaction effects of the bending and axial forces will be demonstrated. While the second element has less error than the first one in thick regimes, the first element can be used for all regimes due to simplicity and good convergence. Based on static responses, it can be deduced that the first element is efficient for all the range of structural characteristics. The free vibration analysis will be performed using the first element. The results of static and dynamic tests show no deficiency, such as, shear and membrane locking and excessive stiff structural behavior.