• The Journal of Korean Physical Therapy
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• v.29 no.2
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• pp.74-79
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• 2017

Purpose: The purpose of this study was to compare the effects of the FES-gait with augmented feedback training to the FES alone on the gait and functional performance in individuals with chronic stroke. Methods: This study used a pretest and posttest randomized control design. The subjects who signed the agreement were randomly divided into 12 experimental groups and 12 control groups. The experimental groups performed two types of augmented feedback training (knowledge of performance and knowledge of results) together with FES, and the control group performed FES on the TA and GM without augmented feedback and then walked for 30 minutes for 40 meters. Both the experimental groups and the control groups received training five times a week for four weeks. Results: The groups that received the FES with augmented feedback training significantly showed a greater improvement in single limb support (SLS) and gait velocity than the groups that received FES alone. In addition, timed up and go (TUG) test and six minute walk test (6MWT) showed a significant improvement in the groups that received FES with augmented feedback compared to the groups that received FES alone. Conclusion: Compared with the existing FES gait training, augmented feedback showed improvements in gait parameters, walking ability, and dynamic balance. The augmented feedback will be an important method that can provide motivation for motor learning to stroke patients.

• Advances in materials Research
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• v.13 no.3
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• pp.211-220
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• 2024

Polylactic acid or polylactide (PLA) is a biodegradable thermoplastic that can be produced from renewable material to create various components for industrial purposes. In 3D printing technology, PLA is used due to its good mechanical, electrical, printing properties, environmentally friendly and non-toxic properties. However, the physical properties and excellent electrical insulation properties of PLA have limited its application. In this study, with the carbon black (CB) as filler added into PLA, the lattice spacing and morphology were investigated by using X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. The physical properties of PLA-carbon composite were evaluated by using tensile test, shore D hardness test and density and voids measurement. Impedance test was conducted to investigate the electrical properties of PLA-Carbon composites. The results demonstrate that the inclusion of carbon black as filler enhances the physical properties of the PLA-carbon composites, including tensile properties, hardness, and density. The addition of carbon black also leads to improved electrical conductivity of the composites. Better enhancement toward the electrical properties of PLA-carbon composites is observed with 1wt% of carbon black in N774 grade. The N550 grade with 2wt% of carbon black shows better improvement in the physical properties of PLA-carbon composites, achieving 10.686 MPa in tensile testing, 43.330 in shore D hardness test, and a density of 1.200 g/cm3 in density measurement. The findings suggest that PLA-carbon composites have the potential for enhanced performance in various industrial applications, particularly in sectors requiring improved physical and electrical properties.

• Journal of the Korea Society of Computer and Information
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• v.18 no.8
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• pp.1-8
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• 2013

This paper proposes an effective parallel implementation of a physical modeling synthesis of guitar on the GPU environment. We used appropriate filter coefficients and adjusted the length of delay line for each open string to generate 44,100 six-polyphonic guitar sounds (E2, A2, D3, G4, B3, E4) by using physical modeling synthesis. In addition, we analyzed the physical modeling synthesis algorithm and observed that we can exploit parallelism inherent in the length of delay line. Thus, we assigned CUDA cores as many as the length of delay line and effectively implemented the physical modeling synthesis using GPU to achieve the highest performance. Experimental results indicated that synthetic guitar sounds using GPU were very similar to the original sounds when we compared their spectra. In addition, GPU achieved 68x and 3x better performance than high-performance TI DSP and CPU, respectively. Furthermore, this paper implemented and evaluated the performance of multi-GPU systems for the physical modeling algorithm.

• Journal of Communications and Networks
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• v.14 no.5
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• pp.518-523
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• 2012

This paper presents new coherent and non-coherent detection methods for the IEEE 802.15.4a low-rate ultra-wideband physical layer with forward error correction (FEC) coding techniques. The coherent detection method involving channel estimation is based on the correlation characteristics of the preamble signal. A coherent receiver uses novel iterated selective-rake (IT-SRAKE) to detect 2-bit data in a non-line-of-sight channel. The non-coherent detection method that does not involve channel estimation employs a 2-bit data detection scheme using modified transmitted reference pulse cluster (M-TRPC) methods. To compare the two schemes, we have designed an IT-SRAKE receiver and a MTRPC receiver using an IEEE 802.15.4a physical layer. Simulation results show the performance of IT-SRAKE is better than that of the M-TRPC by 3-9 dB.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.1
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• pp.127-132
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• 2013

In this paper, we design the physical layer of Guardian modem for wireless public networks. The physical layer is composed of a dual-band RF (Radio Frequency) transceiver and a baseband-processor with quasi-orthogonal codes. The 2.4/5GHz dual-band RF transceiver can overcome the communication difficulty of dense 2.4GHz band for wireless public environment. Also the quasi-orthogonal code can reduce the required ASIC (Application Specific Integrated Circuit) design area. Finally, we analyze the performance of the developed system in viewpoint of data rate, BER (Bit Error Rate), PER (Packet Error Rate). Moreover we verify the performance of the dual-band RF communication.

• Physical Therapy Korea
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• v.27 no.3
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• pp.191-198
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• 2020

Background: Stroke patients experience multiple dysfunctions that include motor and sensory impairments. Therefore, new intervention methods require a gradational approach depending on functional levels of a stroke patient's activity and should include cognition treatment to allow for a patient's active participation in rehabilitation. Objects: This study investigates the effect of integrated revision of electrical sensory stimulation, which stimulates somatosensory and action observation training, which is synchronized cognition intervention method on stroke patients' functions. Methods: Twenty-one stroke patients were randomized into two groups. The two groups underwent twenty minutes of intervention five times a week for three weeks. This study used an electromyogram to evaluate symmetric muscle activation of lower extremities and muscle onset time when performing sit to stand before and after intervention. A weight-bearing ratio was used to evaluate the weight-bearing of the affected side in a sit to standing. To evaluate sit to stand performance ability, this study performed five timed sit to stand tests. Results: The two groups both showed statistically significant improvement in muscle onset time of lower extremity, static balance ability in a standing position, and sit to stand performance after the intervention (p < 0.05). In addition, the action observation and synchronized electrical sensory stimulation group showed significant improvement in symmetric muscle activation of lower extremities and weight-bearing ratio of the affected side (p < 0.05). Conclusion: action observation and synchronized electrical sensory stimulation (AOT with ESS) can have positive effects on a stroke patient's sit to stand performance, and the intervention method that provides integrated AOT with ESS can be used as new nervous system intervention program.

• ETRI Journal
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• v.28 no.5
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• pp.656-659
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• 2006

This letter presents a new polarizer which has a simple comb structure inside a circular waveguide. The electrical performance of the proposed comb polarizer is optimized by a circular waveguide radius and by the physical parameters of the comb plates. This polarizer is suitable for providing good performance in millimeter-band application because of its simple structure and low fabrication cost. In our experiments the dual-band comb polarizer designed in band 1(K) and band 2(Ka) showed good electrical performance without any tuning elements.

• ETRI Journal
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• v.45 no.2
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• pp.213-225
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• 2023

Physical layer security (PLS) can improve the security of both terrestrial and nonterrestrial wireless communication networks. This study proposes a simplified framework for nonterrestrial cyclic prefixed orthogonal variable spreading factor (OVSF)-encoded multiple-input and multiple-output nonorthogonal multiple access (NOMA) systems to ensure complete network security. Various useful methods are implemented, where both improved sine map and multiple parameter-weighted-type fractional Fourier transform encryption schemes are combined to investigate the effects of hybrid PLS. In addition, OVSF coding with power domain NOMA for multi-user interference reduction and peak-toaverage power ratio (PAPR) reduction is introduced. The performance of $\frac{1}{2}$-rated convolutional, turbo, and repeat and accumulate channel coding with regularized zero-forcing signal detection for forward error correction and improved bit error rate (BER) are also investigated. Simulation results ratify the pertinence of the proposed system in terms of PLS and BER performance improvement with reasonable PAPR.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.67-68
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• 2021

Social infrastructure facilities can be destroyed instantly when exposed to EMP (ElectroMagnetic Pulse), causing social chaos. However, concrete structures with low electrical conductivity cannot expect EMP shielding effect. Therefore, in this study, a metal sprayed thin film showing excellent EMP shielding performance was applied to a concrete structure to evaluate the metal spray welding efficiency and adhesion performance of the thin film according to the concrete surface treatment method. As a result according to the concrete surface treatment method, It was confirmed that the use of a roughening agent that generates physical irregularities in order to improve the welding efficiency and adhesion performance increases the physical performance of the concrete and metal sprayed thin film.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.14 no.6
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• pp.525-532
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• 2001

In this paper, physical properties and electrical characteristics of linear low density polyethylene(LLDPE) films blended with ethylene vinyl acetate(EVA), containing polar groups within it, were investigated to improve defects of polyethylene(PE) such like space charge accumulation and tree growth. Blending method changes super-structure of LLDPE, having a great influence on electrical characteristics. For analysis of physical properties, FTIR, XRD and DSC methods were executed, and for electrical characteristics, volume resistivity and dielectric strength were measured with the varying temperature. From the results, it is confirmed that bled specimens tend to be safe to varying temperature, and specially of 70:30 and 50:50 have a good performance.