• The Journal of the Korea Contents Association
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• v.17 no.2
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• pp.439-448
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• 2017

Facial expression is important factor on social interaction. Facial muscle movement provides emotion information to develop social network. However, facial movement has less determined to recognize social emotion. This study is to analyze facial micro-movements and to recognize the social emotion such as intimacy, empathy, and valence. 76 university students were presented to the stimuli for social emotions and was measure their facial expression using camera. As a results, facial micro-movement. showed significant difference of social emotion. After extracting the movement amount of 3 unconscious muscles and 18 conscious muscles, Dominant Frequency band was confirmed. While muscle around the nose and cheek showed significant difference in the intimacy, one around mouth did in the empathy and one around jaw in the valence. The results proposed new facial movement to express social emotion in virtual avatars and to recognize social emotion.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.5
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• pp.464-474
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• 2000

All-to-all personalized communication, or complete exchange, is at the heart of numerous applications, such as matrix transposition, fast Fourier Transform(FFT), and distributed table lookup.We present an efficient all-to-all personalized communication algorithm for a 2D torus inwormhole-routed networks. Our complete exchange algorithm adopts divide-and-conquer approach toreduce the number of start-up latency significantly, which is a good metric for network performancein wormhole networks. First, we divide the whole network into 2x2 basic cells, After speciallydesignated nodes called master nodes have collected messages to transmit to the rest of the basic cell,only master nodes perform complete exchange with reduced network size, N/2 x N/2. When finishedwith this complete exchange in master nodes, these nodes distribute messages to the rest of the masternode, which results in the desired complete exchange communication. After we present our algorithms,we analyze time complexities and compare our algorithms with several previous algorithms. And weshow that our algorithm is efficient by a factor of 2 in the required start-up time which means thatour algorithm is suitable for wormhole-routed networks.

• Journal of the Korea Computer Industry Society
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• v.6 no.5
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• pp.675-686
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• 2005

This paper proposes a new method of mathematically modeling and computer simulating television ghosts wherein television signals that have undergone multipath fading are generated without using approximations by considering the attenuation, time delay, phase, and timing jitter between consecutive frames. Conventional methods used polynomial interpolation or complex arithmetic to take into account the ghost phase, but our method uses only real arithmetic by employing the Hilbert transform and also reduces the computation time using the FFT (fast Fourier transform) algorithm. Furthermore, it is also possible to observe the transmit waveforms in both RF and IF ranges. Various ghost patterns generated in software provide for essential data required for the development of ghost canceling algorithms, and are deemed to be very useful in analyzing the constituent blocks of the transmitter and receiver chain in television broadcasting. The development of ghost cancelers needs to be preceded by the task of mathematically modeling ghosts and their extensive computer simulations.

• Journal of the Korean Society of Safety
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• v.33 no.5
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• pp.9-14
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• 2018

The piping system of a nuclear power plant plays a role of transferring high energy fluid to equipment and various devices. The safety and soundness of these piping systems are very closely related to the operability of the power plant. In the case of a welded part of a small diameter pipe, it may grow as a microcrack due to a lack of penetration, and it may grow to a size that affects the safety of the pipe due to the influence of mechanical vibration and fatigue load. Resonance refers to an increase in energy as the natural frequency of an object coincides with the frequency applied to the external force. When this resonance occurs, the frequency is the resonance frequency. In this study, when defects exist in the welds of small diameter pipe, the natural frequency of the pipe changes and resonance may occur. Since these resonances are likely to cause fatigue damage to the piping, resonance frequency changes due to the size and shape of the defects are analyzed and evaluated. As a result of the vibration test, the resonance frequency tended to decrease as the depth of the defect deepened, and the influence was larger when the defect existed at the bottom of the top of the trough. Also, it was confirmed that the Transverse cracks had an effect on the resonance frequency in the presence of the cracks in the weld bead, compared to the longitudinal cracks. As a result of this study, it is expected that the cause of the defect and the condition of the pipe can be monitored because the resonance frequency tendency according to the shape of the crack is analyzed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.12
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• pp.2270-2278
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• 2017

There are many research to find not only user data but also physical information about objects or human in radio signals. And we can obtain physical information from the wireless signals such as RSSI (Received Signal Strength Indicator), Doppler frequency and other values. For example, the Doppler frequency is generated by the object moving physically in wireless signals used for communication. By analyzing the Doppler frequency, the moving speed and direction of the object can be predicted. In this paper, we study the previous research which is to detect the moving objects or human using wireless signals, 802.11a signals. We introduce and verify the method to improve the frequency domain resolution of commercial 802.11a receivers to observe the doppler frequency and obtain the information of the moving objects or human.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.5A
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• pp.493-500
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• 2006

This paper presents the efficient structure and parameter optimization of downlink beamforming transmitter in OFDMA/TDD system. To design downlink beamforming transmitter for multiple transmit antennas, an efficient beamforming structure for multiple users and the choice of word-length of each block are critical in the aspect of its performance and hardware complexity. We propose an efficient beamforming scheme, which stores the weights of subcarriers into memory without user identification at the receiver of base station and calculates the weights for corresponding user in a subcarrier unit of IFFT input at high speed. Also, we obtain the word-length of main data path and other design parameters by fixed-point simulation analysis. The proposed architecture could reduce the memory size proportional to the maximum number of users per frame, and the processing time of an OFDM symbol at the receiver of base station without the need of additional processing time for calculating the weights at the transmitter.

• Elastomers and Composites
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• v.46 no.4
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• pp.311-317
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• 2011

The neodymium magnet inserted mold was proposed to orient magneto-responsible particles efficiently. The anisotropic magneto-rheological elastomer(MRE) was prepared using the new mold and the optimum amounts of the particles was 30 vol.%. As the orientation of particles was increased, the tensile strength of MRE was decreased, while the hardness of MRE was increased. It was found that the MRE containing 30 vol.% of magneto-responsible particles showed the maximum magneto-rheological effect. The ratio of shear modulus shift was 59% at the input current of 3 A. The transmissibility of MRE was decreased with increasing the input current and loading amounts of magneto-responsible particles. Therefore, the damping property of MRE could be improved by preparing the anisotropic MRE.

• Journal of the Korean earth science society
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• v.26 no.1
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• pp.58-65
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• 2005

Homomorphic filtering improves image by enhancing high components and reducing low components in the Sequency domain based on FFT, as one of useful digital image processing techniques. In this study, the application program f3r homomorphic filtering was developed. Using this program, satellite imageries and geophysical image such as magnetic image data were processed and their results were analyzed. In case of applying to other techniques suck as histogram equalization and kernel-based masking f3r the same purpose. they often cause the slight distortion of boundary or overall change of brightness values on the whole image. Whereas. homomorphic filtering has ability to enhance selectively detailed components in a target image. Therefore. this technique can be effectively used for extraction or separation of complex types of characteristics contained in the satellite imagery. In addition, this technique would be applicable to investigate anomalous zone in various geophysical image data.

• Physical Therapy Korea
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• v.8 no.3
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• pp.63-76
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• 2001

Many studies have shown that the initial median frequency (MDF) and slope correlate with the muscle fiber composition. This study tested the hypothesis that the initial MDF and slope are fixed, regardless of the interval at which data are collected. MDF data using moving fast Fourier transformation of EMG signals, following local fatigue induced by isotonic exercise, were obtained. An inverse FFT was used to eliminate noise, and characteristic decreasing regression lines were obtained. The regression analysis was done in three different periods, the first one third, first half, and full period, looking at variance in the initial MDF, slope, and fatigue index. Data from surface EMG signals during fatiguing isotonic exercise of the biceps brachii and vastus lateralis in 20 normal subjects were collected. The loads tested were 30% and 60% maximum voluntary contraction (MVC) in the biceps brachii and 40% and 80% MVC in the vastus lateralis. The rate was 25 flexions per minute. There were no significant differences in the initial MDF or slope during the early or full periods of the regression, but there was a significant difference in the fatigue index. Therefore, to observe the change in the initial MDF and slope of the MDF regression line during isotonic exercise, this study suggest that only the early interval need to be observed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.7
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• pp.729-738
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• 2010

The characteristics of lifted butane flames diluted with nitrogen have been investigated experimentally in order to elucidate the mechanism of individual flame oscillation modes. Flame oscillations in laminar free-jet lift-off flames are classified into the following five regimes: a stabilized lift-off regime (I), a heat-loss-induced oscillation (II), a buoyancy-induced oscillation along with a heat-loss-induced oscillation (III), a combined form of an oscillation prior to blow-out and a heat-loss-induced oscillation (IV), and a combination of an oscillation prior to blow-out and a buoyancy-induced oscillation along with a heat-loss-induced oscillation (V). The characterization of the individual flame oscillations modes are presented and discussed using Strouhal numbers and their relevant parameters by the analysis of the power spectrum for temporal variation of the lift-off height.