• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.103-111
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• 2002

In RNC of IMT-2000, main control processors such as ASP, ACP and OMP are responsible for call control function, and the high reliability and real-time property should be provided for it. So, the study of real-time fault-tolerant for it is needed. In this paper, we proposes an Task based duplication method, in which Tasks in active side operated on message unit and send the updated data to standby side after operation, log in the message to standby side for recovery during take-over. This scheme decreases the dual down and the complexity of synchronization procedure, and performs the synchronization more exactly because Tasks control the synchronization of system. This paper also proposes the fault detection and the fault handing method for effective implementation of Task based duplication. This scheme focus on increasing the fault detection rate and intercepting originally that fault data is send to standby side.

• Korean Journal of Veterinary Service
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• v.34 no.1
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• pp.13-18
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• 2011

The purpose of this study was to apply a nested-polymerase chain reaction (nPCR) assay to detect and differentiate PCV 2a and PCV 2b. The compared with nPCR and one-step PCR and nPCR showed more sensitive in the detection of PCV-2 from tissue and blood samples. The total of 52 tissue samples was collected from postweanning pigs from 2006 to 2010. All tissue samples showed positive for PCV-2 in one-step PCR and nPCR, followed by the nPCR in order to identify the genotypes of PCV-2. 2 samples (3.8%) showed positive for PCV 2a, and 35 samples were positive for PCV 2b (67.3%), 15 samples (28.9%) were positive the dual genotypes. In addition, 42 blood samples which were collected from the 5 different swine farms were compared figure out the detection rates of nPCR and one-step PCR. The PCV 2 was positive by one-step PCR in 21 samples (50.0%) and nPCR was positive in 37 samples (88.1%). The PCV 2 genotypes in blood samples and 32 samples (76.2%) were positive for PCV 2b and none were positive for PCV 2a, 5 samples (11.9%) were positive for dual genotypes. These results suggest that the nPCR is very efficient for genotyping blood samples and differentiating the genotypes of PCV-2 from field samples.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.783-788
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• 2003

In this paper, we present a new approach to detect and recognize human face in the image from vision camera equipped on the mobile robot platform. Due to the mobility of camera platform, obtained facial image is small and pose-various. For this condition, new algorithm should cope with these constraints and can detect and recognize face in nearly real time. In detection step, ‘coarse to fine’ detection strategy is used. Firstly, region boundary including face is roughly located by dual ellipse templates of facial color and on this region, the locations of three main facial features- two eyes and mouth-are estimated. For this, simplified facial feature maps using characteristic chrominance are made out and candidate pixels are segmented as eye or mouth pixels group. These candidate facial features are verified whether the length and orientation of feature pairs are suitable for face geometry. In recognition step, pseudo-convex hull area of gray face image is defined which area includes feature triangle connecting two eyes and mouth. And random lattice line set are composed and laid on this convex hull area, and then 2D appearance of this area is represented. From these procedures, facial information of detected face is obtained and face DB images are similarly processed for each person class. Based on facial information of these areas, distance measure of match of lattice lines is calculated and face image is recognized using this measure as a classifier. This proposed detection and recognition algorithms overcome the constraints of previous approach [15], make real-time face detection and recognition possible, and guarantee the correct recognition irregardless of some pose variation of face. The usefulness at mobile robot application is demonstrated.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.61-69
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• 2018

In this paper, we propose a method for recognizing ground target using dual polarization channels in millimeter waveband air-to-surface radar. First, the Push-Broom target detection method is described and the received signal is modeled considering flight-path scenario of air-to-surface radar. The scattering centers were extracted using the RELAX algorithm, which is a time domain spectral estimation technique, and the feature vector of the target was generated. Based on this, a DB for 4 targets is constructed. As a result of the proposed method, it is confirmed that the target classification rates is improved by more than 15% than the single channel using the data of the dual polarization channel.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.10 no.8
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• pp.3585-3601
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• 2016

The error rate performance of circularly distributed antenna system is studied over Nakagami-m fading channels, where a dual-channel receiver is employed for the quadrature phase shift keying signals detection. To mitigate the Co-Channel Interference (CCI) caused by the adjacent cells and to save the transmit power, this work presents remote antenna unit selection transmission based on the best channel quality and the maximized path-loss, respectively. The commonly used Gaussian and Q-function approximation method in which the CCI and the noise are assumed to be Gaussian distributed fails to depict the precise system performance according to the central limit theory. To this end, this work treats the CCI as a random variable with random variance. Since the in-phase and the quadrature components of the CCI are correlated over Nakagami-m fading channels, the dependency between the in-phase and the quadrature components is also considered for the error rate analysis. For the special case of Rayleigh fading in which the dependency between the in-phase and the quadrature components can be ignored, the closed-form error rate expressions are derived. Numerical results validate the accuracy of the theoretical analysis, and a comparison among different transmission schemes is also performed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.12 no.3
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• pp.566-574
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• 1988

A study is described for obtaining real time in situ size and velocity measurements of the spray-droplet using crossed-beam interferometry. The optical arrangement is similar to dual-beam laser Doppler velocimetry(LDV). Droplets passing trough the probe volume scatter light to the collecting lens placed at 90.deg. off-axis angle. The dual-beam light scatter is analyzed by the geometric optics theory to relate the scattered fringe pattern to droplet diameter. The droplet size measurement is based upon the signal visibility. As the system is based on the Doppler effect, a single component of velocity is velocity is extracted concurrent with the size information. The validity of the method is evaluated by comparing its performance to widely accepted but limited technique, the collection method. By using 90.deg. off-axis scatter detection angle, the measurement of the droplet size and velocity distributions, and the local correlations between droplet sizes and velocities in relatively dense spray environments are made possible.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.2099-2106
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• 2003

In this paper, a novel fast response NDIR analyzer (FRNDIR), which uses an electrically pulsed semiconductor emitter and dual type PbSe detector for the PPM-level detection of carbon dioxide (CO$_2$) at a wavelength of 4.28 $\mu\textrm{m}$, is described. Modulation of conventional NDIR energy typically occurs at 1 to 20 Hz. To achieve real time high-speed measurement, the new analyzer employs a semiconductor light emitter that can be modulated by electrical chopping. Updated measurements are obtained every one millisecond. The detector has two independent lead selenide (PbSe) with IR band pass filters. Both the emitter accuracy and the detector sensitivity are increased by thermoelectric cooling of up to -20 degrees C in all semiconductor devices. Here we report the use of semiconductor devices to achieve improved performance such that these devices have potential application to CO$_2$ gas measurement and, in particular, the measurement of fast response CO$_2$ concentration at millisecond level.

• Journal of Power Electronics
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• v.11 no.4
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• pp.456-463
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• 2011

Grid-connected converters have widely adopted LCL filters to acquire high harmonic suppression. However, the LCL filter increases the system order so that the design of the system stability would be complicated. Recently, sole-loop control strategies have been used for grid-connected converters with L or LC filters. But if the sole-loop control is directly transplanted to grid-connected converters with LCL filters, the systems may be unstable. This paper presents a novel dual-loop power control strategy composed of a power outer loop and a current inner loop. The outer loop regulates the grid-connected power. The inner loop improves the system stability margin and suppresses the resonant peak caused by the LCL filter. To obtain the control variables, a single-phase current detection is proposed based on PQ theory. The system transfer function is derived in detail and the influence of control gains on the system stability is analyzed with the root locus. Simulation and experimental results demonstrate the feasibility of the proposed control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.7
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• pp.1820-1832
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• 1996

The performance of a carrier recovery is severely degraded because of amplitude fluctuations and random phases of the received signai caused by multipath fading in mobile radio channel. In this paper, we present two kinds of carrier recovery technique using pilot tone such as TCT(Tone Calibration Technique) and DTCT(Dual Tone Calibration Technique) and analyze these performance both in Rayleigh and Rician fadings. we also evaluate the BER performance of two carrier recovery systems in terms of design parameters such as pilot-to-singnal power ratio, and detection filter-to-pilot filter bandwidth ratio.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.20-25
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• 2007

This paper describes a second-generation dual sine-grid surface encoder for 2-D position measurements. The surface encoder consisted of a 2-D grid with a 2-D sinusoidal pattern on its surface, and a 2-D angle sensor that detected the 2-D profile of the surface grid The 2-D angle sensor design of previously developed first-generation surface encoders was based on geometric optics. To improve the resolution of the surface encoder, we fabricated a 2-D sine-grid with a pitch of $10{\mu}m$. We also established a new optical model for the second-generation surface encoder that utilizes diffraction and interference to generate its measured values. The 2-D sine-grid was fabricated on a workpiece by an ultra precision lathe with the assistance of a fast tool servo. We then performed a UV-casting process to imprint the sine-grid on a transparent plastic film and constructed an experimental setup to realize the second-generation surface encoder. We conducted tests that demonstrated the feasibility of the proposed surface encoder model.