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2009| July-August | Volume 55 | Issue 4
September 23, 2009
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Bacterial Foraging Optimization Technique Cascaded with Adaptive Filter to Enhance Peak Signal to Noise Ratio from Single Image
KM Bakwad, SS Pattnaik, BS Sohi, S Devi, BK Panigrahi, Sastry V. R. S. Gollapudi
July-August 2009, 55(4):173-179
This paper proposes a new approach to enhance peak signal to noise ratio of highly corrupted image affected by impulse noise. The proposed technique is implemented using an adaptive median filter and the bacterial foraging optimization (BFO) technique. The adaptive median filter is used to identify pixels affected by noise and replace them with median value to keep the information uncorrupted. The BFO technique minimizes errors between adaptive median filter output image and noisy image to maintain an error percentage of 0.0001. It has been observed that results of the proposed method are superior to conventional methods in terms of perceptual image quality as well as clarity and smoothness in edge regions of the resultant image. This technique can remove the salt-and-pepper noise of highly corrupted images with a noise as high as 90%.
Unified Recursive Structure for Forward and Inverse Modified DCT/DST/DHT
Priyanka Jain, Balbir Kumar, Shail Bala Jain
July-August 2009, 55(4):180-191
This paper proposes implementation of the Modified Discrete Sine Transform (MDST) and Inverse MDST (IMDST) using recursive structures. The formulae required for recursive structures have been derived. Discrete Hartley Transform (DHT), a real-valued transform, is closely related to Discrete Fourier Transform (DFT) of a real-valued sequence and hence its use as an alternative to the Fourier Transform avoids complex arithmetic. This paper presents Modified Discrete Hartley Transform (MDHT)/Inverse MDHT (IMDHT) using Modified Discrete Cosine Transform (MDCT)/Inverse MDCT (IMDCT) and MDST/Inverse MDST (IMDST) recursive structures. The proposed structures are used for simultaneous computation of MDCT/MDST/MDHT of length N (divisible by four) and their Inverse (IMDST/IMDHT). The proposed structures are parallel, simple, regular and therefore highly suitable for VLSI implementation.
Scanning the Issue
Shiban K Koul
July-August 2009, 55(4):147-147
Performance Evaluation of GPR System Using Gaussian Pulse Excitation to Cover Entire Frequency Band of Operation
Abdelhamid A Shaalan
July-August 2009, 55(4):148-153
A differential Gaussian pulse excitation of a transmitting antenna is applied to investigate GPR system performance using two types of proposed antennae, both, partially covered. The first using dipole antenna and the second using bowtie antenna. A good agreement of the calculated results of different antenna parameters with those achieved by applying a sinusoidal source at the feeding of transmitting antenna was predicted for both the cases.
Joint Source and Channel Coding for Real Time H.264 Coded Video Transmission Using Mobile Hand-held Devices
Mohamed Azni, Ramesh Pyndiah, Karim Mokrani, Frederic Guilloud
July-August 2009, 55(4):154-161
This paper proposes a joint source channel coding scheme for robust real time transmission of H.264/AVC coded video over noisy channels and under bandwidth limitations. A new method of rate adaptation to the allowed maximum channel transmission rate which does not assume source rate control in the source coder has been proposed. This keeps system complexity reasonable and improves the perceived decoded video quality. These are desirable features for two-way video-conferencing using mobile hand-held devices. Data partitioning is used to code the source data. Then, unequal error protection is applied at the network abstraction layer. For robustness, we use joint optimization of forward error correction at the transmitter and error concealment at the source decoder. A low complexity and efficient algorithm of channel code rate allocation to the network abstraction layer units is then developed. Simulation results show that the perceived decoded video quality is improved for small levels of signal-to-noise ratio.
New Entropy-Based Method for Gene Selection
Hamid Mahmoodian, MH Marhaban, R Abdul Rahim, R Rosli, I Saripan
July-August 2009, 55(4):162-168
Dimension reduction and selection of a small number of genes with high ability, to discriminate objects, are important challenges in micro-array data analysis. Gene selection, based on top ranked genes which individually have high power to discriminate objects, is a traditional method that doesn't consider the redundancy among the genes. Some results present that subset of genes with low degree of redundancy can show a more comprehensive representation of the targeted classes than one with redundant genes. In this paper, we use Shannon theorem and penalized logistic regression (PLR) as a probability estimator to present a new algorithm for dimension reduction and collect a subset of representative genes of gene expression profile. Breast cancer, leukemia, colon and lung datasets have been classified based on proposed gene selection algorithm by PLR classifier. In most cases the results show a good performance compared to other recent researches.
Design and Realization of Electrostatic Discharge Protected DC to 2GHz GaAs Monolithic Microwave Integrated Circuits SP4T Switch for TDMA Communication Applications
Shib Shankar Singh
July-August 2009, 55(4):169-172
This paper discusses the small signal simulated and measured results of a DC to 2GHz monolithic GaAs SP4T switch which has been designed and realized. The measured 1 dB compression point of SP4T switch at different frequency range has also been presented. The DC to 2GHz switch has been designed using series-shunt FETs topology. This topology has worked over very large bandwidth. In this topology series MESFETs allows the SP4T switch to operate down to DC. The SP4T switch has been achieved better than 1.1dB of insertion loss, better than 32 dB of input to "Off" port isolation and better than 16 dB of the input and output return loss @2GHz. The performance of the SP4T switch has been measured on an FR4 PCB eval board. The on-chip higher value of ballast resistor has been used for ESD protection. The switch has designed using 0.7 mm Ion-Implanted recessed gates MESFET technology and used in switching matrices for TDMA communication system. The major advantages of the solid-state integrated switch are low power consumption, small size and lightweight. These fea tures of solid state switch are more attractive for communication applications. The chip dimension is 1.2 × 1.2 mm.
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