• 대한통합의학회지
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• 제8권3호
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• pp.43-52
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• 2020

Purpose : The aim of this study was to investigate the change of the respiratory function of chronic low back pain patients after the thoracic manipulation and the trunk stability exercise on chronic low back pain patients. Methods : For this study, the group of the experiment was consisted of 44 patients suffering from the low back pain chronically. The participants were divided into two groups: the control group, which was assigned for core stabilization exercise (CSE), and the experimental group, which was randomly assigned for core stabilization exercise after thoracic manipulation (CSE+TM). Both groups carried out each assigned treatment on three times a week for 8 weeks. To study the change related to measurement variable from each test groups before and after intervention, paired t-test was performed. Further, the statistics for an intergroup comparison was analyzed by covariance analysis, ANCOVA. The measurement was conducted by the respiratory function, the respiratory function was measured by forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁). Results : As a result, forced vital capacity (FVC) and forced expiratory volume in one second (FEV₁) showed significant differences not only by each groups but also between those groups before and after the test. Conclusion : In conclusion, both experiments, the core stabilization exercise and the core stabilization exercise conducted after thoracic manipulation, on chronic low back pain patients resulted in the significant level of difference in the respiratory function. This result indicates that the thoracic manipulation is an efficient treatment for improving the respiratory function for chronic low back pain patients.

• 한국세라믹학회지
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• 제39권3호
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• pp.222-225
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• 2002

Microwave dielectric properties of the layered and functionally graded materials (FGMs) of $Mg_{0.93}Ca_{0.07}TiO_3$ (MCT) and $(Ca_{0.3}Li_{0.14}Sm_{0.42})TiO_3$(CLST) were investigated as a function of the volume ratio of two components. Dielectric constant was decreased with an increase of the volume ratio of MCT which had a lower dielectric constant thant CLST. For the layered FGMs specimens, the difference of thermal expansion coefficients between two components induced thermal strain to dielectric layers, which was confirmed by the plot of ${\Delta}$k (X-ray diffraction peak width0 versus k (scattering vector) using the double-peak Lorentzian function, f(x). Quality factor of the specimens was affected by the thermal strain of dielectric layer, especially MCT layer. For the specimen with the volume ratio of MCT/CLST = 2, the qulaity factor of the specimen showed a minimum value due to the maximum thermal strain fo MCT layer.

• 생물정신의학
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• 제21권1호
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• pp.1-13
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• 2014

Normal aging causes changes in the brain volume, connection, function and cognition. The brain changes with increases in age and difference of gender varies at all levels. Studies about normal brain aging using various brain magnetic resonance imaging (MRI) variables such as gray and white matter structural imaging, proton spectroscopy, apparent diffusion coefficient, diffusion tensor imaging and functional MRI are reviewed. Total volume of brain increases after birth but decreases after 9 years old. During adulthood, total volume of brain is relatively stable. After 35 years old, brain shrinks gradually. The changes of gray and white matters by aging show different features. N-acetylaspartate decreases or remains unchanged but choline, creatine and myo-inositol increase with aging. Apparent diffusion coefficient decreases till 20 years old and then becomes stable during adulthood and increase after 60 years old. Diffusion tensor properties in white matter tissue are variable during aging. Resting-state functional connectivity decreases after middle age. Structural and functional brain changes with normal aging are important for studying various psychiatric diseases such as dementia, schizophrenia and bipolar disorder. Our review may be helpful for studying longitudinal changes of these diseases and successful aging.

• 한국전산유체공학회지
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• 제12권2호
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• pp.21-25
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• 2007

A general purpose program NUFLEX has been extended for two-phase flows with topologically complex interface and cavitation flows with liquid-vapor phase change caused by large pressure drop. In analysis of two-phase flow, the phase interfaces are tracked by employing a LS(Level Set) method. Compared with the VOF(Volume-of-Fluid) method based on a non-smooth volume-fraction function, the LS method can calculate an interfacial curvature more accurately by using a smooth distance function. Also, it is quite straightforward to implement for 3-D irregular meshes compared with the VOF method requiring much more complicated geometric calculations. Also, the cavitation process is computed by including the effects of evaporation and condensation for bubble formation and collapse as well as turbulence in flows. The volume-faction and continuity equations are adapted for cavitation models with phase change. The LS and cavitation formulation are implemented into a general purpose program for 3-D flows and verified through several test problems.

• 한국항공우주학회지
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• 제44권7호
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• pp.593-602
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• 2016

본 연구에서는 근접연계방식의 초음속기체 금속분말 미립화장치에 대한 수치해석을 수행하였다. 액체금속의 미립화 과정에서 발생하는 1, 2차 액적분열을 모사하기 위해서 난류 모델을 선정하고 VOF(Volume of Fluid), DPM(Discrete Phase Model) 해석을 차례대로 수행하였다. 해석결과, Level-Set function 분포도를 통해 1차 분열액적의 직경을 계산할 수 있었으며 이 데이터를 DPM 해석에 반영해 도메인 출구에서 수집된 입자들의 최종직경분포를 확인할 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2444-2447
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• 2008

A new 3D-PTV algorithm (a Volume PTV) based upon a hybrid fitness function has been constructed. A coherency fitness function is introduced using the information of space and time to sort out the correct particle pairs between the two camera images. The measurement system consists of two-high-definition-cameras($1k{\times}1k$), a Nd-Yag laser and a host computer. The developed algorithm has been employed to investigate the flow features of the cylinder wake. The Reynolds numbers with the cylinder diameter (d=10mm) are 360, 720, 900 and 1260. Two-dimensional displacements of the particles of each camera's image and neighbouring constraints were introduced to reduce the calculation loads. More than 10,000 instantaneous 3D vectors have been obtained by the constructed algorithm. The constructed algorithm could recover more than $80{\sim}90%$ of the particle numbers in the image.

• PNF and Movement
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• 제16권3호
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• pp.389-395
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• 2018

Purpose: The purpose of this study was to investigate whether the respiratory function of patients with stroke was different on the ground and under water. Methods: We recruited 14 adults who had experienced a stroke (12 male, 2 female) for our study. We measured forced vital capacity, forced expiratory volume at one second, maximum inspiratory pressure, and maximum expiratory pressure when the participants breathed on the ground and under water. On the ground, the participants were safely supported using a table and chair and were measured in a standing posture. For measuring under water, the participants were immersed in water in a standing position to clavicle height. The participants were measured while standing, and the assistant supported them when they needed help. The collected data were analyzed by a paired t-test. Results: Forced vital capacity and forced expiratory volume at one second were significantly lower in water than on the ground when breathing at maximum. Maximum inspiratory pressure was not significantly different when standing on the ground or in water, but maximum expiratory pressure was significantly higher in water than on the ground. Conclusion: It has been confirmed that the hydrostatic pressure affecting stroke patients immersed in water affects the forced expiratory volume at one second while reducing the forced vital capacity and increasing the maximum expiratory pressure.

• Computers and Concrete
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• 제29권 6호
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• pp.361-374
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• 2022

On the premise of ensuring that the automatic and quantitative discharging function of concrete conveyors is met, the accuracy of the weight forecast by the mathematical model of the screw conveying volume is improved, and the error of the weight of the concrete parts and the accumulation thickness is reduced. In this paper, the discrete element method (DEM) is used to simulate the macroscopic flow of concrete. Using the concrete discrete element model, the size of the screw conveyor is set, and establish the response model between the influencing factors (process and structure) and the concrete mass flow rate according to the design points of the screw discharging experiment. The nonlinear data fitting method is used to obtain the volumetric efficiency function under the influence of process and structural factors, and the traditional screw conveying volume model is improved. The mass flow rate of concrete predicted by the improved mathematical model of screw conveying volume is consistent with the test results. The model can accurately describe the conveying process of concrete and achieve the purpose of improving the accuracy of forecasting the weight of discharged concrete.

• 대한후두음성언어의학회지
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• 제17권2호
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• pp.115-126
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• 2006

Background and Objectives : Training of breath support and laryngeal muscles control are important components in the development of the singing voice. The purpose of this study is to compare characteristics of respiratory and phonatory control on pitch, loudness, register change with untrained males and trained male singers. Materials and Methods : The 11 untrained males and 11 trained male singers participated. Closed Quotient(CQ), fundamental frequency (fo) and relative volume contribution of the rib cage (in percentage rib cage, % RC) and relative volume contribution of abdomen (in percentage abdomen, % AB) were measured during various pitch, loudness, register tasks using /a/ vowel phonation : Legato, staccato with C3-D3-E3-F3-G3 notes and crescendo and decrescendo with C3 note as well as modal register with C3 and falsetto register with C4 note using an integrated analysis system of Respiration, EGG and Voice. Results : (1) When pitch increased with legato task, loudness also increased in untrained male group but maintained in trained male singers. CQ was also increased both untrained and trained male singers but it was not significantly different ($p>.05$). The abdomen contribution to lung volume were significantly predominant both in inhalation and exhalation in trained males singers ($p<.05$). (2) When pitch increased with staccato task, CQ was not significantly different in untrained but significantly different in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$) (3) When loudness increased with crescendo, fo was significantly increased with increasing CQ in untrained males but fo was relatively consistent with increasing CQ in trained male singers. The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). (4) Most male singers were able to change register from modal to falsetto register, but untrained males were not. Thus, CQ was significantly different between modal and falsetto register in trained male singers ($p<.05$). The respiratory function of male singers were characterized by significantly predominant abdomen contribution to lung volume in exhalation except for inhalation ($p<.05$). Conclusion : Male singers were superior to untrained males in coordination of respiratory and phonatory control on pitch, loudness, register change. Implication are offered regarding how the results might be applied to the voice therapy as well as singing training.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.461-464
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• 2003

A new control volume finite element method is proposed for three dimensional analysis of polymer flow. Tetrahedral finite element is employed and co-located interpolation procedure for pressure and velocity is implemented. Inclusion of pressure gradient term in the velocity shape functions prevents the checkerboard pressure field from being developed. Vectorial nature of pressure gradient is considered in the velocity shape function so that velocity profile in the limit of very small Reynolds number becomes physically meaningful. The proposed method was verified through three dimensional simulation of pipe flow problem for Newtonian and power-law fluid. Calculated pressure and velocity field showed an excellent agreement with analytic solutions for pressure and velocity. Driven-cavity problem, which is reported to yield checkerboard pressure filed when conventional finite element method is applied, could be solved without yielding checkerboard pressure field when the proposed control volume finite element method was applied. The proposed method could be successfully applied to the three dimensional mold filling problem.