• Therapeutic Science for Rehabilitation
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• v.10 no.2
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• pp.141-150
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• 2021

Objective : In this study, the upper extremity use, executive function, and occupational performance effects of cognitive orientation to daily occupational performance (CO-OP) interventions for patients with stroke were assessed. Methods : The study was designed as a single-group pre-post test with 20 sessions. The participants were five hospitalized patients with stroke who were present in a rehabilitation setting, and their onsets were more than 3 months previously. Outcomes were measured using the Canadian Occupation Performance Measure (COPM), Performance Quality Rating Scale (PQRS), Executive Function performance Test - Korean version (EFPT-K), and Motor Activity Log (MAL). The Wilcoxon signed-rank test was conducted to determine the difference between the pre-and-post of CO-OP interventions. The statistical significance level was p<.05. Results : The upper extremity function showed significant changes and the execution function showed significant changes in preparation, sequencing, judgment and safety, and closing, except for items to be started. The performance of the task also showed significant changes. Conclusion : Through 20 sessions of CO-OP interventions, especially in patients with chronic stroke, the upper extremity function, execution function, and task performance were improved. We found that CO-OP intervention had a positive effect on the improvement of detailed task elements as well as the performance of tasks overall, in patients with stroke.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.3
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• pp.48-57
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• 2005

This paper presents a novel algorithm in order to extract lane-related information based on machine vision techniques. The algorithm makes up for the weak points of the former method, the Edge Distribution Function(EDF)-based approach, by introducing a Lane Boundary Pixel Extractor (LBPE) and the well-known Hough Transform(HT). The LBPE that serves as a filter to extract pixels expected to be on lane boundaries enhances the robustness of machine vision, and provides its results to the HT implementation and EDF construction. The HT forms the accumulator arrays and extracts the lane-related parameters composed of orientation and distance. Furthermore, as the histogram of edge magnitude with respect to edge orientation angle, the EDF has peaks at the orientations corresponding to lane slopes on the perspective image domain. Therefore, by fusing the results from the EDF and the HT the proposed algorithm improves the confidence of the extracted lane-related information. The system shows successful results under various degrees of illumination.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.459-461
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• 2004

This paper presents an implementation of real-time speaker localization using audio-visual information. Four channels of microphone signals are processed to detect vertical as well as horizontal speaker positions. At first short-time average magnitude difference function(AMDF) signals are used to determine whether the microphone signals are human voices or not. And then the orientation and distance information of the sound sources can be obtained through interaural time difference and interaual level differences. Finally visual information by a camera helps get finer tuning of the speaker orientation. Experimental results of the real-time localization system show that the performance improves to 99.6% compared to the rate of 88.8% when only the audio information is used.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.05a
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• pp.111-115
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• 2003

Nanoindentation is simply an indentation test in which the length scale of the penetration is measured in nanometres rather than microns or millimetres, the latter being common in conventional hardness tests. Three-dimensional molecular dynamics simulations have been conducted to evaluate the nanoindentation test. Molecular dynamics simulations were carried out on single crystal copper by varying crystal orientations to investigate nano-behavior of material beneath an indenter in nanoindentation. Morse potential function was used as an interatomic force between indenter and thin film. The result of the simulation shows that crystal orientation significantly influenced the slip system, dislocation nucleation and dislocation behavior.

• Journal of Advanced Marine Engineering and Technology
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• v.27 no.1
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• pp.100-107
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• 2003

This study was to control magnetic field orientation-typed sensorless vector control by applying the theory of a rotor flux observer to drive an induction motor. This research suggested a new speed estimation method that estimates speed with the rotor flux obtained by using a flux observer and the variable of state current detected by a current sensor without a speed sensor. Because the speed estimation method is independent from the motor constants, it is not necessary to control the gain of the parameters and the algorithm is simple. In the findings of the study, the researcher was convinced of the control function and the possibility of realization in the simulation experiment of sensorless vector control system by using DSP(Digital Signal Prosessor).

• Computers and Concrete
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• v.10 no.2
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• pp.105-119
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• 2012

This paper presents the mix composition and production method that was applied to an extruded Ductile Fiber Reinforced Cement Composite (DFRCC) panel, as well as the flexural performance, represented by deformation hardening behavior with multiple cracking. The effect of fiber distribution characteristics on the flexural behavior of the panel is also addressed. In order to demonstrate the fiber distribution effect, a series of experiments and analyses, including a sectional image analysis and micromechanical analysis, was performed. From the experimental and analysis results, it was found that the flexural behavior of the panel was highly affected by a slight variation in the mix composition. In terms of the average fiber orientation, the fiber distribution was found to be similar to that derived under the assumption of a two-dimensional random distribution, irrespective of the mix composition. In contrast, the probability density function for the fiber orientation was measured to vary depending on the mix composition.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2661-2665
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• 2011

We studied the effect of structural and morphological changes on the conductivity of a stretched conducting polymer film. To improve the poor processability of polyaniline, we used dodecylbenzenesulfonic acid as both a surfactant and a dopant during emulsion polymerization, followed by blending with high-impact polystyrene. UV-Vis/NIR spectra were obtained to observe conformational changes, and SEM and AFM were used to investigate morphological changes. FT-IR dichroism was applied to determine the microscopic orientation, and XRD patterns were obtained for quantitative crystallinity analysis. The electrical conductivity (${\sigma}_{\parallel}/{\sigma}_{\perp}$) was measured as a function of draw ratio. We found a clear correlation between morphological changes and (${\sigma}_{\parallel}/{\sigma}_{\perp}$), especially at the stretching limit. The conductivity of the films can be modified according to the desired application by controlling their structure and morphology.

• Journal of the Korean Ceramic Society
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• v.43 no.3 s.286
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• pp.152-155
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• 2006

Silicon carbide ceramics seeded with 10-30 wt% SiC whiskers are fabricated by hot pressing and annealing. A quantitative texture analysis including calculation of the Orientation Distribution Function (ODF) is used for obtaining the degrees of preferred orientation of the fabricated samples. The microstructure and crystallographic texture are discussed with respect to the effect of ${\beta}-SiC$ whisker seeds on the resulting fracture toughness values. The SEM microstructures and the texture data reveal a correlation between texture and fracture toughness anisotropy.

• Transactions on Electrical and Electronic Materials
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• v.11 no.6
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• pp.285-287
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• 2010

This paper introduces homogeneous liquid crystal (LC) orientations on chemically modulated polystyrene (PS) surfaces using various ion beam (IB) exposure times. Transparent PS was replaced with conventional polyimide material. As a non-contact process, the IB bombardment process induced LC orientation parallel to the IB process. Through x-ray photoelectron spectroscopy, it was shown that the chemical compositional changes of the IB-irradiated PS surfaces were determined as a function of IB exposure time. Using this analysis, the optimal IB bombardment condition was determined at an IB exposure time of up to 15 seconds. Moreover, thermal stability on IB-irradiated PS surfaces were carried out which showed that a relatively high IB exposure time induced a thermally stable LC alignment property.

• Journal of Mechanical Science and Technology
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• v.17 no.9
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• pp.1332-1338
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• 2003

To estimate the true wear rate of polyethylene acetabular cups used in total hip arthroplasty, the dynamic compressive creep deformation of ultra-high molecular weight polyethylene (UHMWPE) was quantified as a function of time, load amplitude, and radial location of the specimen in the extruded rod stock. These data were also compared with the creep behavior of polyethylene observed under static loading. Total creep strains under dynamic loading were only 64％, 70％, and 61％ of the total creep strains under static loading at the same maximum pressures of 2 MPa,4 MPa, and 8 MPa, respectively. Specimens cut from the periphery of the rod stock demonstrated more creep than those cut from the center when they were compressed in a direction parallel to the extrusion direction (vertical loading) whereas the opposite was observed when specimens were compressed in a direction perpendicular to the extrusion direction (transverse loading). These findings show that creep deformation of UHMWPE depends upon the orientation of the crystalline lamellae.