• Journal of Energy Engineering
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• v.17 no.4
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• pp.189-197
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• 2008

In this study, a system to measure continuously the fuel concentration in a steady flow rig on the basis of Rayleigh scattering is presented. The system can be employed to measure both the temporal and the spatial distribution. Also, it is possible to calibrate the system for the measurement of accurate absolute concentration. Firstly, the system was tested at a calibration chamber for the determination of scattering cross section from propane, butane, acetylene, Freon-12 and Genetron 143a. After this, the system was adapted to a steady flow rig to measure the temporal and spatial fuel concentration. The rig is composed of cylinder head, intake manifold, injector, and transparent cylinder which can simulate internal combustion engine. To cope with the interference of Mie scattering, which is main obstacle of the measuring concentration with Rayleigh scattering, a hardware filter was installed for reducing the number density of particles. Furthermore a software filter was developed, which is based on the rise time and the time constant of the photomultiplier-amplifier system. In addition, background noisy was reduced by adjusting the optical array and applying the pin hall and beam trap. The results show that LRS can provide useful information about concentration field and the software filter is very effective method to remove Mie interference.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.46 no.6
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• pp.102-111
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• 2009

In this paper, we propose a de-interlacing algorithm that combines a motion compensation (MC) method and the vertical-temporal filter with motion compensation (MC V-T filter) according to motion compensation reliability. The MC method represent one of the best ways of improving the resolution of de-interlaced frames, but it may introduce motion compensation artifacts in regions with incorrect motion information. In these regions, the MC V-T filter that is very robust to motion vector errors can be used to correct motion compensation artifacts. The combination between two methods is controlled by the motion compensation reliability that is measured by analyzing the estimated motion vectors and the results of MC. The motion compensation reliability contains information about motion compensation artifacts of MC results and determines the combination weight according to this information. Therefore, the combination rule of the proposed method is more accurate than those of the conventional methods and it enables the proposed method to provide high quality video sequences without producing any visible artifacts. Experimental results with various test sequences show that the proposed algorithm outperforms conventional algorithms in terms of both visual and numerical criteria.

• Journal of agriculture & life science
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• v.45 no.3
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• pp.89-96
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• 2011

The objective of this study is to evaluate reduction efficiency of various air purifiers on airborne microorganism causing air infected animal disease according to sample collection method. Collection efficiencies of MS2 virus and Pseudomonas fluorescens by biosampler was significantly higher than those by button sampler (p<0.05). Regardless of types of air purifier and sample collection method, temporal reduction efficiencies of MS2 virus and P. fluorescens compared to initial background concentration were >50% and >45% on 5 minutes, >70% and >50% on 15 minutes, >80% and >70% on 30 minutes and >90% and >75% on 60 minutes after operating air purifier, respectively. The air purifier of ionizer type showed the highest reduction efficiency on MS2 virus followed by air purifier of electronic precipitation, water filter and dry filter while the reduction efficiency of air purifier on P. fluorescens was highest in the electronic precipitation type followed by ionizer type, dry filter type and water filter type (p<0.05). Based on the results obtained from this study, temporal reduction efficiency of air purifier on MS2 virus was relatively higher than P. fluorescens.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.87-97
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• 2004

In this paper, we propose an algorithm for interlaced-to-progressive conversion by the weighted summation of the information collected from spatial do-interlacing method, in which the weighted edge based line average is applied, and the temporal method in which the motion compensation is employed by using hi-directional BMA (block matching algorithm). We employed time-recursive and motion adaptive processing as motion detection is involved. Also, a median filter is used to deal with limitation of the linear summation in which only an intermediate of values being involved is determined. The main goal of the approach is to overcome the shortcomings of each of the do-interlacing techniques without significant increment of the computational complexity, and the proposed method is apt to implement in hardware for real-time processing.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.1
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• pp.39-51
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• 2012

Aerosol slurry samples were collected in 60-min interval using Korean Semi-continuous Elements in Aerosol Sampler (KSEAS) between May 19 and June 6, 2010 at an urban site of Gwangju. The $PM_{2.5}$ samples were collected with a flow rate of 16.7 L/min and particles are grown by condensation of water vapor in a condenser maintained at ${\sim}5^{\circ}C$ after saturation by direct injection of steam. The resulting droplets are collected in a liquid slurry with a airdroplet separator. Concentrations of 16 elements (Al, Fe, Mn, Ca, K, Cu, Zn, Pb, Cd, Cr, Ti, V, Ni, Co, As, Se) in the collected slurry samples were determined off-line by ICP-MS. KSEAS sample analysis encompassed the sampling periods for which 24-hr average elemental species concentrations were calculated for comparison with those derived from 24-hr integrated filter samples. Relationship between elemental species measured by two methods indicated high correlation coefficients (r), mostly greater than r of 0.80. However, we note that concentrations of Al, K, Ca, Mn, and Fe, which are often associated with crustal elemental particles, in the KSEAS samples, were substantially lower (1.4~11 times) than those found in the typical filter-based samples. This discrepancy is probably due to difficulties in transferring insoluble dust particles to the collection vials in the KSEAS. Temporal profiles of elemental concentrations indicate that some transient events in their concentrations are observed over the sampling periods. For the elemental species studied, atmospheric concentrations during the transient events increased by factors of 4 in Mn~80 in Zn, compared to their background levels. Principle component analyses were applied to the hourly KSEAS data sets to identify sources affecting the concentrations of the metal constituents observed. In this study, we conclude that hourly measurements for particle-bound elemental constituents were extremely useful for revealing the short-term variability in their concentrations and developing insights into their sources.

• Journal of Advanced Navigation Technology
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• v.17 no.6
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• pp.757-764
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• 2013

A panoramic video which supports to make viewers feel an immersion through fitting to a wide field of view (FOV) larger than the human visual angle needs an interactive viewing method such as selecting targeted view point among widely viewing points of a panoramic video because it difficult to simultaneously view a whole panoramic video due to a limited viewing environment and bandwidth. When a user officially uses a view navigation in order to select a view point, it happens waste of resources such as bandwidth owing to the transmitted video data of unnecessary view points. Therefore, this paper proposes the spatial-temporal prediction filter (STPF) which is based on the direction and velocity of the view navigation for transmitting only the necessary video data. As a result of simulation, STPF reduces bitrate saving rates by from 6% to 37% compared to conventional methods in the interactive panoramic video streaming service required high bandwidth.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.40 no.1
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• pp.139-147
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• 2003

Dynamic neural networks have been applied to diverse fields requiring temporal signal processing such as signal prediction. This paper proposes the hybrid network, composed of locally(LRNN) and globally recurrent neural networks(GRNN), to improve dynamics of multilayered recurrent networks(RNN) and then describes nonlinear adaptive prediction using the proposed network as an adaptive filter. The hybrid network consists of IIR-MLP and Elman RNN as LRNN and GRNN, respectively. The proposed network is evaluated in nonlinear signal prediction and compared with Elman RNN and IIR-MLP networks for the relative comparison of prediction performance. Experimental results show that the hybrid network performs better with respect to convergence speed and accuracy, indicating that the proposed network can be a more effective prediction model than conventional multilayered recurrent networks in nonlinear prediction for nonstationary signals.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.3
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• pp.120-126
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• 2005

This paper presents the 3D wavelet based video compression system using quad-tree algorithm. The 3D wavelet based video compression system removes the temporal correlation of the input sequences using the motion compensation filter and decomposes the spatio-temporal subband using the spatial wavelet transform. The proposed system allocates the higher bit rate to the low frequency image of the 3D wavelet sequences and improves the 0.64dB PSNR performance of the reconstructed image in comparison with that of H.263. In addition to the limitation on the propagation of the motion compensation error by the 3D wavelet transform, the proposed system progressively transmits the input sequence according to the resolution and rate scalability.

• Journal of Broadcast Engineering
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• v.1 no.1
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• pp.7-13
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• 1996

MASF is a kind of temporal filter proposed for noise reduction and temporal band limitation. MASF uses motion vectors to extract temporal information in spatial domain. Therefore, inaccurate motion information causes some distortions in MASF operation. Currently, bilinear interpolation after BMA(Block Matching Algorithm) is used for the motion estimation sheme of MASF. But, this method results in unreliable estimation when the object in image sequence has larger movement than the maximum displacement assumed in BMA or the input images are severely corrupted with noise. In order to i:;olve this problem, we analyse the effect of inaccurate motion on MASF and propose a hierarchical motion estimation algorithm based on the analysis results. Experimental results show that the proposed method produces reliable output under large motion and noisy situations.

• Journal of Sensor Science and Technology
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• v.21 no.2
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• pp.144-150
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• 2012

A microphone for fully implantable hearing device was generally implanted under the skin of the temporal bone. So, the implanted microphone's characteristics can be affected by the accompanying noise due to masticatory movement. In this paper, the implantable microphone with 2-channels structure was designed for reduction of the generated noise signal by masticatory movement. And an experimental model for generation of the noise by masticatory movement was developed with considering the characteristics of human temporal bone and skin. Using the model, the speech signal by a speaker and the artificial noise by a vibrator were supplied simultaneously into the experimental model, the electrical signals were measured at the proposed microphone. The collected signals were processed using a general adaptive filter with least mean square(LMS) algorithm. To confirm performance of the proposed methods, the correlation coefficient and the signal to noise ratio(SNR) before and after the signal processing were calculated. Finally, the results were compared each other.