• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.2
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• pp.1-8
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• 2020

In the case of power plant facilities, seismic stability of non-structural elements is important. In particular, Cabinet structures to which electrical equipment is attached, should have functional safety against earthquakes. Therefore, in this study the dynamic characteristics of non-structural elements inside existing power plant buildings were identified and the response level generated during dynamic behavior was analyzed. In addition, The steel plate dampers were adopted and adjusted to suit the size of the target equipment. In order to derive the optimal seismic reinforcement, the variables according to the attachment location were set and the responses were analyzed by the seismic movement input before and after reinforcement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.895-906
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• 2014

A fundamental study of the dynamically penetrating anchor (DPA - colloquially known as torpedo anchor) embedded into deep seabed was conducted using measurement data and numerical approaches. Numerical simulation of such a structure penetration was often suffered by severe mesh distortion arising from very large soil deformation, complex contact condition and nonlinear soil behavior. In recent years, a Coupled Eulerian-Lagrangian method (CEL) has been used to solve geomechanical boundary value problems involving large deformations. In this study, 3D finite element analyses using the CEL formulation are carried out to simulate the construction process of dynamic anchors. Through comparisons with results of field measurements, the CEL method in the present study is in good agreement with the general trend observed by in-situ measurements and thus, predicts a realistic large deformation movement for the dynamic anchors by free-fall dropping, which the conventional FE method cannot. Additionally, the appropriate parametric studies needed for verifying the characteristic of dynamic anchor are also discussed.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.6
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• pp.436-441
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• 2013

An experiment using a 5 m-long sand column was performed to evaluate the resisting capability against micro-pollutants of the infiltration gallery, multi-purpose filtration pond and riverbank/bed filtration, of which the filtration distance is becoming increasingly shorter in Korea. Results suggested that the Korean riverbed sand contained significant amount of organics, resulting in a relatively vigorous adsorption of chloride ion on the sand surface. Results also indicated that while phenol was not detected in the column filtrate, both 1,4-dioxane and diazinon were exposed to adsorption by the sand as they moved through the column, decreasing their peak concentrations during the movement. It can be expected that the peak concentrations will diminish significantly in the practical scale due to its longer travel distance.

• The Journal of Korean Physical Therapy
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• v.24 no.2
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• pp.151-156
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• 2012

Purpose: The purpose of this study was to investigate the adverse effects of sensorimotor function at the shoulder joint according to long-term cane usage in stroke patients without apraxic behavior, in terms of the presence of shoulder joint pain, accuracy of tracking task, proprioceptive joint position sense, and nine-hole pegboard. Methods: Nineteen stroke patients with long-term cane usage (cane usage group) and nineteen stroke patients without cane usage (non-cane usage group) were recruited. All subjects were tested in pain presence, a tracking task for visuomotor function, joint reposition, and nine-hole pegboard in the shoulder joint regarding the non-affected side. Results: In the accuracy index for tracking task and the nine-hole pegboard test, significant differences were observed between the cane usage group and the non-cane usage group. However, although a higher emergence of shoulder pain and a lower accuracy for joint reposition sense were detected in the cane usage group in comparison to the non-cane usage group, there were no significant differences between the two groups. Conclusion: Our findings suggest that long-term cane usage could induce to decrease in delicate movement and coordination in the non-affected upper arm in stroke patients. In addition, they could experience high frequency of shoulder pain and poor joint reposition sense. Therefore, careful evaluation and observation will be required concerning stroke patients with long-term cane usage.

• The Journal of Korean Physical Therapy
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• v.22 no.2
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• pp.25-30
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• 2010

Purpose: Behavior and movement are accomplished by voluntary contractions of skeletal muscles. There are three types of muscle contractions: concentric, isometric and eccentric. The aim of our study was to determine whether there is a difference in the cortical activation pattern between concentric contraction and eccentric contraction of the wrist extensor muscle. Methods: Four healthy right-handed volunteers without any previous history of physical or neurological illness were recruited. fMRI scanning was done during 4 repeated blocks of concentric and eccentric exercise of the wrist joint. Subjects exercised for 12 seconds and then rested for 12 seconds before beginning the second set of exercises. To determine the excitability of cortical neurons during exercise, voxel count and intensity index were analyzed. Results: For right hand movements, when concentric contractions of the right wrist were done, only the left primary motor area was activated. In contrast, during eccentric contraction, both the primary motor area and secondary motor area were activated. For left hand movements, both concentric and eccentric contractions induced only the supplementary motor cortex and the contralateral primary motor cortex. Conclusion: During eccentric contractions, both the primary motor area and secondary motor area are activated in ipsilateral and contralateral brain areas. Thus, eccentric contractions require more complex and difficult movements than concentric contractions do.

• The Journal of Engineering Geology
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• v.23 no.3
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• pp.217-225
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• 2013

We carried out geometrical, kinematic, and geomechanical analyses on a lineament (the Imgok fault) near Gangneung, observed in ASTER images and aerial photographs, and field surveys. Earthquake focal mechanism solutions, used to estimate the present-day stress state, revealed that the direction of maximum compression is approximately N$70^{\circ}$E and that the stress condition is in favor of either strike-slip or reverse movement on the fault. The strike of the fault is not ideal for slip under the present-day stress field and thus the fault has a low slip tendency. However, the fault may be able to slip if the frictional coefficient (${\mu}$), representing the resistance of the fault to slip, is sufficiently low (e.g., ${\mu}$ < 0.25).

• Journal of Oriental Neuropsychiatry
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• v.19 no.2
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• pp.95-110
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• 2008

Objective : This experiment was designed to investigate the effects of the PMCMT hot water extract & ultra-fine powder on Alzheimer's Disease Model Induced by ${\beta}A$. Method : The effects of the PMCMT hot water extract on expression of proinf1ammatory cytokine mRNA in BV2 microglial cell cell line treated by lipopolysacchaide(LPS). The effects of the PMCMT hot water extract & ultra-fine powder on (1) the behavior (2) AChE in serum (3) the infarction area of the hippocampus, and brain tissue injury in Alzheimer's diseased mice induced with ${\beta}A$ were investigated. Result : 1. The PMCMT hot water extract suppressed the expression of proinflammatory cytokine mRNA in BV2 microglial cell line treated with LPS. 2. The PMCMT hot water extract & ultra-fine powder a significant inhibitory effect on the memory deficit was shown for the mice with Alzheimer's disease induced by ${\beta}A$ in the Morris water maze experiment, which measured stop-through latency and distance movement-through latency 3. The PMCMT hot water extract & ultra-fine powder suppressed the over-expression of AChE activity in the serum of the mice with Alzheimer's disease induced by ${\beta}A$. 5. The PMCMT ultra-fine powder reduced infarction area of hippocampus significantly, and the PMCMT hot water extract & ultra-fine powder controlled the injury of brain tissue in the mice with Alzheimer's disease induced by ${\beta}A$. Conclusions : These results suggest that the PMCMT hot water extract & ultra-fine powder may be effective for the prevention and treatment of Alzheimer's disease. Investigation into the clinical use of the PMCMT hot water extract & ultra-fine powder for Alzheimer's disease is suggested for future research.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1465-1477
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• 1993

Powder Injection Molding(PM) is an advanced and complicated technology for manufacturing ceramic or metal products making use of a conventional injection molding process, which is generally used for plastic products. Among many technologies involved in the successful PIM, injection molding process is one of the key steps to form a desired shape out of powder/binder mixtures. Thus, it is of great importance to have a numerical tool to predict the powder injection molding filling process. In this regard, a finite element analysis system has been developed for numerical simulations of filling process of powder injection molding. Powder/polymer mixtures during the filling pro cess of injection molding can be rheologically characterized as Non-Newtonian fluids with a so called yield phenomena and have a peculiar feature of apparent slip phenomena on the wall boundaries surrounding mold cavity. Therefore, in the present study, a physical modeling of the filling process of powder/polymer mixtures was developed to take into account both the yield stress and slip phenomena and a finite element formulation was developed accordingly. The numerical analysis scheme for filling simulation is accomplished by combining a finite element method with control volume technique to simulate the movement of flow front and a finite difference method to calculate the temperature distribution. The present study presents the modeling, numerical scheme and some numerical analysis results showing the effect of the yield stress and slip phenomena.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.5
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• pp.2403-2407
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• 2012

Finite number of pile elements are considered in load transfer method. And section force and movement of each pile element are computed by considering compatibilities between pile displacement and the load transfer along a pile and between displacement and resistance at the tip of the pile. For the conventional load transfer method, large amount of computations due to iterations are needed. Formulation of finite difference equation from the differential equation which depicts pile behavior under axial loading was accomplished in order to simplify the computation for obtaining pile section forces and displacements. By comparing the results between the simplified computation method and the reported data, there was no difference between the two results.

• Journal of KIISE:Software and Applications
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• v.28 no.10
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• pp.757-763
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• 2001

This paper propose a new clustering algorithm called G-CLUS based on the relative gravitation. In this method every instance has the same mass at first. the gravitations among instances make each instance move to the attractive direction gradually and eventually natural clusters are formed without the initial seed and the number of clusters. Our proposed method can determine the number of clusters via a process of gravitational agglomeration and it can reduce the sensitivity to outliers by using the resultant of gravitation. We also improved the computational complexity by applying the concept of a cube to the proposed algorithm. In our experiments, we show the behavior of instance movement clustering process for each model, clustering process and the results for an example data set, and the results of comparison between the other clustering algorithm and our proposed. method.