• Smart Structures and Systems
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• v.18 no.4
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• pp.683-705
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• 2016

A semi-active algorithm for edgewise vibration control of the spar-type floating offshore wind turbine (SFOWT) blades, nacelle and spar platform is developed in this paper. A tuned mass damper (TMD) is placed in each blade, in the nacelle and on the spar to control the vibrations for these components. A Short Time Fourier Transform algorithm is used for semi-active control of the TMDs. The mathematical formulation of the integrated SFOWT-TMDs system is derived by using Euler-Lagrangian equations. The theoretical model derived is a time-varying system considering the aerodynamic properties of the blade, variable mass and stiffness per unit length, gravity, the interactions among the blades, nacelle, spar, mooring system and the TMDs, the hydrodynamic effects, the restoring moment and the buoyancy force. The aerodynamic loads on the nacelle and the spar due to their coupling with the blades are also considered. The effectiveness of the semi-active TMDs is investigated in the numerical examples where the mooring cable tension, rotor speed and the blade stiffness are varying over time. Except for excessively large strokes of the nacelle TMD, the semi-active algorithm is considerably more effective than the passive one in all cases and its effectiveness is restricted by the low-frequency nature of the nacelle and the spar responses.

• Korean Journal of Adult Nursing
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• v.24 no.3
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• pp.305-316
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• 2012

Purpose: The purpose of this study was to test the effectiveness of a cognitive rehabilitation program for the patients having an acute stroke. The variables evaluated were cognitive function, depression and activities of daily living (ADLs). Methods: A non-equivalent control group pretest-posttest design with sixty-two subjects from two separated institutions was the design for the study. Thirty-three patients were assigned to the treatment group and 29 patients comprised the comparison group. The treatment group participated in the nursing intervention for cognitive rehabilitation for a three week period of time. The study was conducted from September 2010 to April 2011. Results: Following the three week intervention, the cognitive function and activities of daily living of the treatment group were significantly improved compared to the comparison group (t=6.33, p<.001; t=4.57, p<.001). Specifically, depression was significantly decreased in the treatment group (t=3.95, p<.001). Conclusion: The cognitive rehabilitation program was effective in increasing the treatment group cognitive function and activities of daily living along with a decrease in depression scores. Therefore, Cognitive Rehabilitation Program could be expected a beneficial nursing intervention in stroke patients.

• Journal of ILASS-Korea
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• v.15 no.3
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• pp.131-139
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• 2010

Gas motion within the engine cylinder is one of the major factors controlling the fuel-air mixing and combustion processes in diesel engines. In this paper, a special swirl-chamber is designed and applied to a DI (direct injection) diesel engine to generate a strong swirl motion thus enhancing gas motion. Compression, combustion and expansion strokes of this DI diesel engine with the swirl-chamber have been simulated by CFD software. The simulation model was first validated through comparisons with experimental data and then applied to do the simulation of the spray and combustion process. The velocity and temperature field inside the cylinder showed the influences of the strong swirl motion to spray and combustion process in detail. Cylinder pressure, average temperature, heat release rate, total amount of heat release, indicated thermal efficiency, indicated fuel consumption rate and emissions of this DI diesel engine with swirl-chamber have been compared with that of the DI diesel engine with $\omega$-chamber. The conclusions show that the engine with swirlchamber has the characteristics of fast mixture formulation and quick diffusive combustion; its soot emission is 3 times less than that of a $\omega$-chamber engine; its NO emission is 3 times more than that of $\omega$-chamber engine. The results show that the DI diesel engine with the swirl-chamber has the potential to reduce emissions.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.492-495
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• 1999

In this paper, a research is focused on implementation of the handwritten Korean-character recognition system using a neural coprocessor for PDA application. The proposed coprocessor is composed of a digital neural network called DMNN and a RISC-based dedicated controller in order to achieve high speed as well as compactness. Two neural networks are used for recognition, one for stroke classification out of extended 11 strokes and the other for grapheme classification. Our experimental result shows that the successful recognition rate of 92.1% over 3,000 characters written by 10 persons can be obtained. Moreover, it can be improved to 95.3% when four candidates are considered. The design verification of tile proposed neural coprocessor is conducted using the ASIC emulator for further hardware implementation.

• Journal of Magnetics
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• v.19 no.3
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• pp.300-308
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• 2014

This paper develops a moving-magnet electromagnetic actuator for fast steering mirror (FSM). The actuator achieves a reasonable compromise between voice coil actuator and piezoelectric actuator. The stroke of the actuator is between the strokes of a piezoelectric actuator and a voice coil actuator, and its force output is a linear function of air gap and excitation current within our FSM travel range. Additionally, the actuator is more reliable than voice coil actuator as the electrical connection in the actuator is static. Analytically modeling the actuator is difficult and time-consuming. Alternatively, numerous finite element simulations are carried out for the actuator analysis and design. According to the design results, a real prototype of the actuator is fabricated. An experimental test system is then built. Using the test system, the force output of the fabricated actuator is evaluated. The test results validate the actuator analysis and design.

• Journal of Oriental Neuropsychiatry
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• v.13 no.2
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• pp.75-92
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• 2002

To evaluate the relations between strokes and psychological characteristics, the authors surveyed Minnesota Multiphasic Personal Inventory(MMPI) in CVA Patients. The results are as follows.1. In the cerebral infarction patients group, the measure of F, Hy, Pd, Pt and Sc has appeared significantly high. 2. In the cerebral hemorrhage patients group, the measure of F and Ma has appeared significantly high. 3. In dysphasia-hemiparesis patients group, the measure of D has appeared high.4. In the Soyangin patients group, the measure of Pd and Ma has appeared high. 5. In the Soeumin patients group, the measure of D, Pt and Si has appeared high.

• Korean Journal of Applied Biomechanics
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• v.28 no.3
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• pp.151-158
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• 2018

Objective: In this study, we analyzed kinematic changes in the start phase of speed skating before and after physical training. Method: We introduced a new strength training program (2017) that was improved in terms of exercise type and intensity [%, one repetition maximum (1RM)] compared with the previous strength training program (2016). The new program was applied to elite speed skating athletes (four males and four females). To determine the improvement in starting technique, we recorded race images during the start phase of the 500-m race held in 2016 and 2017. The race images were collected using five high-speed cameras and kinematic characteristics of the start phase were analyzed by three-dimensional image analysis. Results: The 1RMs were improved by 11% on an average after the strength training. In 2017, records of four out of the eight athletes were shortened in terms of the initial lap time (100 m), and 500-m records were shortened in six athletes. The time to nine strokes was shortened in five athletes, and the ratio of correct kinetic chain was increased or maintained at a high level in six athletes. Conclusion: In this study, the new strength training program (2017), applied to elite speed skating athletes, showed a positive effect on starting technique and reduced the record times.

• Smart Structures and Systems
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• v.26 no.5
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• pp.545-558
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• 2020

A design method of a Multiple Tuned Mass Damper (MTMD) system is presented for wind induced vibration control of a cable-supported roof structure. Modal contribution analysis is carried out to determine the dominating modes of the structure for the MTMD design. Two MTMD systems are developed for two most dominating modes. Each MTMD system is composed of multiple TMDs with small masses spread at multiple locations with large responses in the corresponding mode. Frequencies of TMDs are distributed uniformly within a range around the dominating frequencies of the roof structure to enhance the robustness of the MTMD system against uncertainties of structural frequencies. Parameter optimizations are carried out by minimizing objective functions regarding the structural responses, TMD strokes, robustness and mass cost. Two optimization approaches are used: Single Objective Approach (SOA) using Sequential Quadratic Programming (SQP) with multi-start method and Multi-Objective Approach (MOA) using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The computation efficiency of the MOA is found to be superior to the SOA with consistent optimization results. A Pareto optimal front is obtained regarding the control performance and the total weight of the TMDs, from which several specific design options are proposed. The final design may be selected based on the Pareto optimal front and other engineering factors.

• Journal of Korea Multimedia Society
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• v.20 no.4
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• pp.713-720
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• 2017

We present a non-photo realistic pen-ink drawing method for outlining and shading of the input image. Especially, we focus on the detailed illustration of the image of which stroke's direction is important. The pen-ink renderer is an alternative display models user can generate traditional illustration renderings of their photo realistic image. The previously proposed pen drawing methods produce feasible description in general image but it is difficult to express in detail for the sophisticated images that need to consider the direction of stroke for each image region. In order to overcome the disadvantages of the conventional method, a direction vector is extracted from a tensor field and we determine a stroke's direction in consideration of not only an edge area but also a gradient of a surrounding area in the image. For more detailed description for the sophisticated image, we generate white noises based on the light and shade of the input image and determine the direction and length of the stroke by using the tensor field for each generated white noise. The proposed method works particularly well for traditional architectural images where the direction and detailed description of the pen is important.

• Journal of Broadcast Engineering
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• v.22 no.2
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• pp.253-256
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• 2017

This paper deals with the implementation of speech disorder detection system based on machine learning classification. Problems with speech are a common early symptom of a stroke or other brain injuries. Therefore, detection of speech disorder may lead to correction and fast medical treatment of strokes or cerebrovascular accidents. The speech disorder system can be implemented by extracting features from the input speech and classifying the features using machine learning algorithms. Ten machine learning algorithms with various scaling methods were used to discriminate speech disorder from normal speech. The detection system was evaluated by the TORGO database which contains dysarthric speech collected from speakers with either cerebral palsy or amyotrophic lateral sclerosis.