• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.301-309
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• 2020

Objective: This study aimed to investigate the effect of white noise on dynamic balance in patients with stroke during walking. Method: Nineteen patients with chronic stroke (age: 61.2±9.8 years, height: 164.4±7.4 cm, weight: 61.1±9.4 kg, paretic side (R/L): 11/8, duration: 11.6±4.9 years) were included as study participants. Auditory stimulus used white noise, and all participants listened for 40 minutes mixing six types of natural sounds with random sounds. The dynamic balancing ability was evaluated while all participants walked before and after listening to white noise. The variables were the center of pressure (CoP), the center of mass (CoM), CoP-CoM inclined angle. Results: There is a significant increase in the antero-posterior (A-P) CoP range, A-P inclination angle, and gait speed on the paretic and non-paretic sides following white noise intervention (p<.05). Conclusion: Our findings confirmed the positive effect of using white noise as auditory stimulus through a more objective and quantitative assessment using CoP-CoM inclination angle as an evaluation indicator for assessing dynamic balance in patients with chronic stroke. The A-P and M-L inclination angle can be employed as a useful indicator for evaluating other exercise programs and intervention methods for functional enhancement of patients with chronic stroke in terms of their effects on dynamic balance and effectiveness.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.41 no.3
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• pp.25-32
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• 2004

An advanced algorithm for measurement of phase angle between two sinusoidal signals is proposed in this paper. This algorithm uses discrete sample data of two input signals for calculation of phase angle and amplitude. And the key parameters of the measurement algorithm are described by analytical express, so the calculation of phase angle is simplified. In this paper it is proved that harmonic distortion of the input sinusoidal signals does not affect the measurement value of phase angle by using the proposed algorithm when a whole cycle is sampled. And measurement error by the white Gaussian noise is very small compared by other algorithms.

• Journal of Korean Association for Spatial Structures
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• v.2 no.4 s.6
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• pp.29-36
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• 2002

The responses of composite laminated beams modeled with finite element and excited by stochastic loading are studied. The cantilevered laminated beam having a 5 ply configuration is considered. The beam is 1m long, 0.1m wide, and 0.02m thick, yielding a length to thickness ratio of L/h=50. The laminated beams was assumed to be made of Born Epoxy. The four nodes at the free end of the cantilever were loaded with identical zero-mean white noise excitations. Stress and failure analysis loaded with identical zero-mean white noise excitations is carried out. Along with the obtained results, comparison and discussion are presented for the cases of symmetric-ply, antisymmetric-ply, angle-ply, and cross-ply laminated beams.

• Journal of the Optical Society of Korea
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• v.17 no.5
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• pp.415-422
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• 2013

White-light phase-shifting interferometry (WLPSI) is widely recognized as a standard method to measure shapes with high resolution over a long distance. In practical applications, WLPSI, however, is associated with some degree of ambiguity of its phase, which occurs due to a phase delay, which is the offset between the phase of the fringes and the fringe envelope peak position. In this paper, a new algorithm is proposed for the determination of a fringe order suitable for samples in which the phase delay mainly occurs due to noise, diffraction and a steep angle. The concepts of the decouple factor and the connectivity are introduced and a method for calculating the decouple factor and the connectivity is developed. With the phase-unwrapping procedure which considers these values, it is demonstrated that our algorithm determines the correct fringe order. To verify the performance of the algorithm, a simulation was performed with the virtual step height under noise. Some specimens such as step height standard and a column spacer with a steep angle are also measured with a Mirau interference microscope, after which the algorithm is shown to be effective and robust.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1211-1215
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• 2003

Accurate mathematical models of spacecraft components are an essential of spacecraft attitude control system design, analysis and simulation. Gyro is one of the most important spacecraft components used for attitude propagation and control. Gyro errors may seriously degrade the accuracy of the calculated spacecraft angular rate and of attitude estimates due to inherent drift and bias errors. In order to validate this model, nominal case simulation has been performed and compared for the low range mode and high range mode, respectively. In this paper, a mathematical model of gyro containing the relationships for predicting spacecraft angular rate and disturbances is proposed.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.868-872
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• 2005

Individual management of the animal is the first step towards reaching the goal of precision livestock farming that aids animal welfare. Accurate recognition of each individual animal is important for precise management. Electronic identification of cattle, usually referred to as RFID (Radio Frequency Identification), has many advantages for farm management. In practice, however, RFID implementations can cause several problems. Reading speed and distance must be optimized for specific applications. Image processing is more effective than RFID for the development of precision farming system in livestock. Therefore, the aim of this paper is to attempt the identification of cattle by using image processing. The majority of the research on the identification of cattle by using image processing has been for the black-and-white patterns of the Holstein. But, native Japanese and Korean cattle do not have a consistent pattern on the body, so that identification by pattern is impossible. This research aims to identify to Japanese black cattle, which does not have a black-white pattern on the body, by using image processing and a neural network algorithm. 12 Japanese black cattle were tested. Values of input parameter were calculated by using the face image values of 12 cows. The face was identified by the associate neural memory algorithm, and the algorithm was verified by the transformed face image, for example, of brightness, distortion, noise and angle. As a result, there was difference due to a transformation ratio of the brightness, distortion, noise, and angle. The algorithm could identify 100% in the range from -30 to +30 degrees of brightness, -20 to +40 degrees of distortion, 0 to 60% of noise and -20 to +30 degree of angle transformed images.

• Journal of the Korean Society for Precision Engineering
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• v.17 no.1
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• pp.45-51
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• 2000

In this Paper a basic technique of gantry robot control system has been developed to weld the curved part of a large structure. A welding robot is designed to rotate torch and make the torch angle normal to the welding surface. The Kalman filter is applied to obtain the smooth welding path signal from the noised Sensing data. A welding path finding algorithm has been developed in Turbo-C language.

• ETRI Journal
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• v.38 no.3
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• pp.560-567
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• 2016

To solve the problem of parameter optimization in image sensor-based visible light positioning systems, theoretical limits for both the location and the azimuth angle of the image sensor receiver (ISR) are calculated. In the case of a typical indoor scenario, maximum likelihood estimations for both the location and the azimuth angle of the ISR are first deduced. The Cramer-Rao Lower Bound (CRLB) is then derived, under the condition that the observation values of the image points are affected by white Gaussian noise. For typical parameters of LEDs and image sensors, simulation results show that accurate estimates for both the location and azimuth angle can be achieved, with positioning errors usually on the order of centimeters and azimuth angle errors being less than $1^{\circ}$. The estimation accuracy depends on the focal length of the lens and on the pixel size and frame rate of the ISR, as well as on the number of transmitters used.

• Journal of radiological science and technology
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• v.32 no.2
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• pp.177-182
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• 2009

Purpose : This study presents the optimization of flip angle (FA) to obtain higher contrast to noise ratio (CNR) and lower specific absorption rate (SAR). Materials and Method : T1-weighted images of the cerebrum of brain were obtained from 50$^\circ$ to 130$^\circ$ FA with 10$^\circ$ interval. Signal to noise ratios (SNRs) were calculated for white matter (WM), gray matter (GM), and background noise. The proper FA was analyzed by T-test statistics and Kruskal-wallis analysis using R1 = 1- exp ($\frac{-TR}{T1}$) and Ernst angle cos $\theta$ = exp ($\frac{-TR}{T1}$). Results : The SNR of WM at 130$^\circ$ FA is approximately 1.6 times higher than the SNR of WM at 50$^\circ$. The SNR of GM at 130$^\circ$ FA is approximately 1.9 times higher than the SNR of GM at 50$^\circ$. Although the SNRs of WM and GM showed similar trends with the change of FA values, the slowdown point of decrease after linear fitting were different. While the SNR of WM started decreasing at 120$^\circ$ FA, the SNR of GM started decreasing at less than 110$^\circ$. The highest SNRs of WM and GM were obtained at 130$^\circ$ FA. The highest CNRs, however, were obtained at 80$^\circ$ FA. Conclusion : Although SNR increased with the change of FA values from 50$^\circ$ to 130$^\circ$ at 3T SE T1WI, CNR was higher at 80$^\circ$ FA than at the usually used 90$^\circ$ FA. In addition, the SAR was decreased by using smaller FA. The CNR can be increased by using this optimized FA at 3T MR SE T1WI.

• Progress in Superconductivity
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• v.5 no.2
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• pp.94-97
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• 2004

Step-edge Josephson junctions (SEJ) have been fabricated on sapphire substrates with in situ deposited films of CeO$_2$ buffer layer and YBa$_2$Cu$_3$O$_{7}$ films on the low angle steps. Direct coupled SQUID magnetometers with the SEJ were formed on 1 cm X 1 cm R-plane sapphire substrates. Typical 5-${\mu}{\textrm}{m}$-wide Josephson junctions have R$_{N}$ of 3 Ω and I$_{c}$ of 50 $mutextrm{A}$ at 77 K. The direct coupled SQUID magnetometers were designed to have pickup coils of 50-${\mu}{\textrm}{m}$-wide 16 parallel loops on the 1 cm X 1 cm substrates with outer dimension of 8.8 mm X 8.8 mm. The SEJ SQUID magnetometers exhibit relatively low 1/f noise even with dc bias control, and could be stably controlled by flux-locked loops in the magnetically disturbed environment. Field noise of the do SQUID was measured to be 200∼300 fT/Hz$^{1}$2/in the white noise region and about 2 pT/Hz$^{1}$2/ at 1 Hz when measured with dc bias method.hod.d.