Search

Summary: The MIMO‐OFDM increases spectral efficiency without the use of channel state information (CSI). However, the bit error rate (BER) in the MIMO‐OFDM model increases dramatically due to the increase in nonlinear distortion in the power amplifier (PA). In this research, a novel pre‐coder integrated MIMO‐OFDM technology is designed for effective BER reduction, and its performance is analyzed. The discrete wavelet‐based OFDM system is one of the key ideas to present good orthogonal by emphasizing orthogonal wavelets. It helps to mitigate inter‐symbol interference (ISI) and noise within the channel by extending the bandwidth (BW) compared to conventional OFDM systems. But, DWT‐OFDM highly suffered due to downsampling, which degrades system efficiency. To overcome this, a redundant discrete wavelet transform (RDWT) is proposed in this article to enhance spectral efficiency. For modulation, 16‐bit quadrature amplitude modulation (QAM) is introduced in this work. In addition to this, a block bi‐diagonalization (BBD) pre‐coder technique is proposed to mitigate unwanted noise and interference in the MIMO‐OFDM system. The performance measures such as ergodic sum capacity, BER, throughput, average jitter noise power, mean square error (MSE), and power consumption are analyzed using the MATLAB platform. The proposed method obtains the ergodic sum capacity of 6.25 bps/Hz, a BER of 0.021, a throughput of 95.2%, MSE of −0.47, and a power consumption of 1.15 μW. The simulative results prove the efficacy of the proposed method. [ABSTRACT FROM AUTHOR]

This paper presents a compact asymmetric CPW fed monopole antenna using Denim fabric as substrate applicable for UWB communication and various wireless body area networks (WBANs). The geometry of the antenna consists of a circular monopole antenna with a modified ground plane and introduction of defected ground structures (DGS) to achieve ultra-wide band (3.10-10.6 GHz) characteristics. The proposed wearable antenna operates from 2.40 to 14.88 GHz providing a fractional bandwidth (FBW) of about 144.44%. Enhancement of the bandwidth is obtained by the insertion of open ended rectangular slit in the ground plane. The final antenna produces a peak gain of about 6.57 dBi at 13.05 GHz and achieved omnidirectional radiation patterns. In terms of return loss, gain, and radiation characteristics, the lightweight flexible wearable antenna is fabricated, and the tested effects are found to be in fair accordance with the simulated ones. [ABSTRACT FROM AUTHOR]

Summary: A thriving number of physical objects are being connected to the Internet wirelessly in an unparalleled manner registering the goal for Internet of Things. This paper proposed a cost effective low profile compact dual band resonant consumer monopole antenna of dimensions of 13 mm × 12 mm × 1.6 mm that is less than an area of a thumbnail or more or less similar to a micro‐SD card. The designed transceiver antenna is easy to fabricate and capable of operating at sub C‐band (3.4–3.6 GHz) for possible future fifth generation (5G) applications and 5.8G Wi‐Fi (5.725–5.825 GHz) band enabling home automation facilities. The proposed design accomplishes almost omni‐directional radiation pattern at the duplex bands, and the measured results are being validated with the simulated ones, which shows good agreement. [ABSTRACT FROM AUTHOR]

Summary: This article represents a microstrip line–fed novel circular monopole antenna with ultra‐wideband (UWB) characteristics. The compact antenna provides reconfigurable notches at WLAN (5.2/5.8 GHz) and Wi‐MAX (5.5 GHz) frequency bands. The band rejection is achieved by etching an open‐ended L‐shaped slot in the ground plane, which effectively mitigates the interference between WLAN, Wi‐MAX, and UWB systems with an effective patch area of 36.26%. The proposed antenna operates from 3.05 to 12.11 GHz with VSWR ≤ 2 except at stopband (3.89‐5.93 GHz) to filter the WLAN and Wi‐MAX signals. The simulated return loss, gain, and radiation pattern of the proposed antenna has been experimentally verified with the fabricated one which holds a good agreement. [ABSTRACT FROM AUTHOR]

This article presents a compact circular-sectored microstrip antenna embedded with circular slots and a sectoral ground plane for enhanced bandwidth and applicable for UWB communications exhibiting an equivalent Fractional Bandwidth of 156.04% (2.5–20.25 GHz) and allows a compactness of about 79.15% using Rogers RT-Duroid 5880 as a substrate for lesser surface wave loss and attaining broader bandwidth. The gain of the antenna ranges from 1.85 to 6.10 dBi throughout the resonant frequency band and the results obtained from measurement are validated to justify the applicability of this antenna for various WLAN and Wi-MAX frequency bands. [ABSTRACT FROM AUTHOR]

In this paper, a wideband printed polygon-shaped monopole antenna has been designed using microstrip line feeding technique which provides dual-notch band characteristics (2.98–3.19 GHz) and (3.62–5.00 GHz) by the use of slots geometry in both the patch and the ground plane. The results of the antenna have been compared both with and without slots in both planes. The initial antenna without DGS and slots in the patch was made to work in the frequency range from 2.56–5.98 GHz having impedance bandwidth of about 80.09%. The proposed antenna can be made usable for multi-band applications such as WLAN (2.4/3.2/5.2/5.8 GHz) and Wi-MAX (3.5 and 5.5 GHz) applications providing fractional bandwidth (FBW) of 85.36% (2.33–5.80 GHz) and maximum peak gain of 5.65 dBi at 3.50 GHz. The value of return loss obtained is about 53.36 dB at 2.56 GHz. Prototype of the final antenna is fabricated and the results are verified with the simulated ones. [ABSTRACT FROM AUTHOR]

In this paper, we have proposed the optimized BCD to Excess-3 code converter using reversible logic gate. BCD to Excess-3 code can be generated by adding "0011" to BCD number, but in the proposed work, addition is not required. The proposed reversible circuit can be designed using peres gate, Feynman gate and NOT gate optimized quantum cost, garbage output and constant input. The quantum cost (QC), garbage output and constant input of proposed reversible BCD to Excess-3 code converter are respectively 14, 1 and 1 which is better with respect to previously reported results. The improvement is, respectively 0–65%, 66.66–91.66% and 66.66–87.5%. [ABSTRACT FROM AUTHOR]

Multimodal Magnetic Resonance Imaging (MRI) is an imaging technique widely used in the diagnosis and treatment planning of patients. Lesion segmentation of brain MRI is one of the most important image analysis task in medical imaging. In this paper, a new method for the supervised segmentation of the lesion in brain MRI using Grammatical Bee Colony (GBC) is proposed. The segmentation process is adversely affected by the presence of noises and intensity inhomogeneities in the Magnetic Resonance (MR) images. Therefore, noises are removed from the images and intensity inhomogeneities are corrected in the pre-processing steps. A set of stationary wavelet features are extracted from the co-registered 1-weighted (-), 2-weighted (-) and Fluid-Attenuated Inversion Recovery (FLAIR) images after skull stripping. A classifier is evolved using the GBC to classify the tissues as healthy tissues or lesions. The GBC classifier is trained with extracted features. The trained classifier is used to segment the test Magnetic Resonance (MR) image into healthy tissues or lesion regions. Finally, the connected component labeling algorithm is used to extract the lesions from the segmented images in the post-processing step. Effectiveness of the proposed method is tested by identifying the brain lesions from a set of MR images. [ABSTRACT FROM AUTHOR]

The proposed work deals with a real time hourly internet traffic data set in bits collected from ISPs located in 11 cities of European Country for the period 7th June 2005 to 31st July 2005. Then a thorough statistical inference has been drawn regarding the central tendency, dispersion and distribution of the data. Time-frequency analysis using Smoothed Pseudo Wigner Ville Distribution (SPWVD) is implied to infer knowledge about the non-stationarity of the system. A nonparametric test for normality, Anderson Darling Test (AD-Test) has been performed to detect the binary signature of nonlinearity in the signal. Delay Vector Variance Analysis (DVV) are being exploited to infer deeper knowledge about the determinism and nonlinearity in the system. The results confirm a nonstationary, relatively stochastic and nonlinear profile of the signal under observation. [ABSTRACT FROM AUTHOR]

A single-layer coaxial-fed compact rectangular microstrip antenna with very low voltage standing wave ratio (VSWR) is presented in this paper. The simulated VSWR of the proposed antenna 1.00374 is obtained near the center frequency of the operating band (3.5 GHz). Simulation and measurement results indicate that the bandwidth (simulated: 3.36–3.715 GHz, and measured: 3.295–3.645 GHz) of the antenna exceeds 10% below VSWR 2, when the size reduction of the antenna is about 81.6%. The realized peak gain is obtained about 2.15 dBi at 3.5 GHz. For the verification of the computational results, two designs were fabricated and measured. Good agreements between simulated and measured results were found. [ABSTRACT FROM PUBLISHER]

An improved glowworm swarm optimization algorithm with generalized opposition-based learning is proposed in this paper and is used in segmentation for magnetic resonance images. Noises are removed and intensity inhomogeneities are corrected in the MR images. Next, a clustering technique with glowworm swarm optimization algorithm with generalized opposition based learning is used. Finally, lesions are separated from the normal tissues of the brain in the post-processing step. The performance of the proposed methodology based on both numerical and visual results are compared with K-means and particle swarm optimization based methodologies over two sets of MR images. The experimental results demonstrate that the proposed methodology statistically outperforms other methodologies. [ABSTRACT FROM AUTHOR]

In this paper the authors have proposed a new 3x3 reversible gate and also proposed the reversible combinational logic circuits with better optimized quantum cost, garbage outputs and delay. The proposed new reversible logic gate is used to design of reversible 1-bit comparator circuit and realization of different logic functions such as NOT, AND, NAND, OR, NOR, XOR, NXOR. The proposed new reversible logic gate is represented by quantum implementation. The quantum cost of proposed gate is 4. The quantum cost, garbage output and delay of proposed reversible 1-bit comparator circuit are 6 which is better w. r. t. previously reported results. [ABSTRACT FROM AUTHOR]

Background: The complaint of insomnia is one of the most common symptoms a physician encounters in his/her day-to-day practice. Though rarely present as the stand-alone problem, it accompanies other organic or psychological symptoms. Its incidence is on the rise in ever increasing stressful life of present times. Objectives: The objective was to study the prevalence and some sociodemographic factors associated with insomnia among the urban population of Kamarhati municipal area of district 24 Parganas (N) of the state West Bengal. Materials and Methods: The study was carried out at "Kamarhati" municipal area. Ten percent of householders of two randomly selected wards were surveyed. Self-reported sleep questionnaire insomnia symptoms questionnaire (ISQ) was administered to all adult members. Persons with a history of major psychiatric illness, regular shift work, daily alcohol consumption more than four units and on chemotherapy or radiotherapy were excluded from the survey. Results: ISQ identified 15.4% prevalence of insomnia. It was high in persons with co-morbid chronic physical illness (28.1%) compared to persons free from that (10.9%) (P < 0.001). Insomnia was significantly higher among people living in joint families than those living in a nuclear family. The prevalence of insomnia increases significantly with the increasing age (P < 0.05). Conclusion: Findings of this study showed that the prevalence of insomnia in urban India is high. Increased life expectancy, increased burden of chronic illnesses, changing lifestyle, uncertainty of urban life contributes to high prevalence of insomnia that in turn affects quality of life. [ABSTRACT FROM AUTHOR]

This paper presents a new method for the segmentation of Magnetic Resonance Imaging (MRI) of brain tumor. First, discrete wavelet transform (DWT)-based soft-thresholding technique is used for removing noise in the MRI. Second, intensity inhomogeneity (IIH) independent of noise is removed from the MRI image. Third, again DWT is used to sharpen the de-noised and IIH corrected image. In this method, the image is decomposed into first level using wavelet decomposition and approximate values are assigned to zero and reconstruct the image results in detailed image. The detailed image is added with the pre-processed image to produce sharpened image. Entropy maximization using Grammatical Swarm (GS) algorithm is used to obtain a set of threshold values and a threshold value is selected with the expert knowledge to separate the lesion part from the other non-diseased cells in the image. [ABSTRACT FROM AUTHOR]

This paper presents a single-layer co-axial fed compact rectangular microstrip antenna for 2.4/5.2/5.8 GHz WLAN applications. The antenna consists of four rectangular and one triangular slot inside the patch and one rectangular open-ended slot inside the ground plane. Measured impedance bandwidths (2.36–2.485 and 5.14–6.43 GHz) show that the antenna is suitable for the applications in WLAN IEEE 802.11b/g and IEEE 802.11a bands. [ABSTRACT FROM AUTHOR]

In this paper, a search is made to detect any sort of nonlinearity and chaos in the solar irradiance data from the Earth Radiation Budget Satellite during the time period from October 15, 1984 to October 15, 2003 in order to investigate the inherent complexity in it. In this paper, delay vector variance analysis has been applied to trace the nonlinearity; whereas 0–1 test, correlation dimension analysis, information entropy, recurrence plot, and recurrence quantification analysis have been used to explore the signature of chaos in the present time series. Present investigation reveals that though nonlinearity is significantly present in the signal, chaotic behavior is not really observed in it. [ABSTRACT FROM PUBLISHER]

A method of progressive transmission of Magnetic Resonance Image with lesions over long distances is proposed. The Magnetic Resonance Images at the transmitter end are segregated on the basis of presence of lesions. Entropy Maximization using Hybrid Particle Swarm Optimization algorithm that incorporates a Wavelet theory based mutation operation is used for segmentation of Magnetic Resonance Images. It applies the Multi-resolution Wavelet theory to overcome the stagnation phenomena of the Particle Swarm Optimization. Thus the segmentation algorithm using Hybrid Particle Swarm Algorithm explores the solution space more effectively for a better solution. Varying percentages of Discrete Cosine Transform coefficients of segmented Magnetic Resonance Images are used for progressive image transmission. For a particular image data, the progressively received images are of different resolutions. At the receiver's end the progressively received images of different resolutions are fused using Multi-resolution wavelet analysis to get a visually suitable image for diagnosis. The doctor or a radiologist identifies a particular class of image with lesions and may ask for the entire un-segmented Magnetic Resonance Image dataset of a particular patient for further diagnosis. The proposed system helps to reduce the load on the system by choosing not to transmit the Magnetic Resonance Images without lesions. [ABSTRACT FROM AUTHOR]

In this article, the method of nullifying the radiation pattern of a symmetric linear antenna array in a particular direction is propounded using an evolutionary swarm intelligence technique, Novel particle swarm optimization (NPSO). Particle swarm optimization with constriction factor approach (PSOCFA) is also adopted to compare the NPSO based results. Single or multiple wide nulls are achieved by optimum perturbations of elements current amplitude weights to have symmetric nulls about the main beam. Different numerical examples are presented to illustrate the capability of NPSO for pattern synthesis with a prescribed wide nulls locations and depths. Further, the peak Sidelobe Levels are also reduces when compared to a uniformly excited array having equal number of elements. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. [ABSTRACT FROM AUTHOR]

A concentric circular antenna array (CCAA) consists of elements positioned on the periphery of imaginary circles on a plane having a common centre and different radii. The simplest way to feed the elements of such an array is to use uniform excitation. However, with a non-uniform excitation profile, considerable reduction of the side lobe level (SLL) may be achieved at the cost of the added complexity. The difference of SLLs (with respect to the uniform excitation case) becomes even more prominent when the beam width of the antenna needs to be kept fixed. In this paper, we formulate the task of designing a non-uniformly excited CCAA as a constrained optimization problem and use genetic algorithm (GA) to solve the same. The goal is to determine an optimum set of weights for antenna elements which provides a radiation pattern with maximum SLL reduction with the constraint of a fixed beamwidth. [ABSTRACT FROM AUTHOR]

In this article, two optimization heuristic search techniques, craziness-based particle swarm optimization (CRPSO) and CRPSO with wavelet mutation (CRPSOWM), are applied to the process of optimal designing three-ring concentric circular antenna arrays (CCAAs) focused on maximum sidelobe level (SLL) reduction. Hence, three-ring CCAA without and with central element feeding are considered. SLL is a critical radiation pattern parameter in the task of reducing background noise and interference in the most recent wireless communication systems. To improve the radiation pattern with maximum SLL reduction, an optimum set of antenna element parameters as excitation weights and radii of the rings is to be developed. This is an optimization problem dealing with complex, highly nonlinear, discontinuous, and nondifferentiable array factors of CCAA design. So, one evolutionary optimization technique as CRPSO is adopted. To enhance the optimization performance of CRPSO further in exploring the solution space more effectively for a better solution, the wavelet theory is again applied in terms of mutation. This wavelet mutation-based CRPSO is named as CRPSOWM. It is shown that the proposed CRPSOWM technique outperforms the CRPSO significantly in terms of convergence speed, solution quality, and solution robustness. Computational results finally reveal that among the various CCAA designs, the design containing central element and four, six, and eight elements in three successive concentric rings proves to be the near global optimal design with near global minimum SLL (-43.4 dB) as determined by CRPSOWM. Real coded genetic algorithm (RGA) and its wavelet-based improved version (RGAWM) as well are also adopted to compare the results of above particle swarm optimization–based algorithms. © 2010 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [ABSTRACT FROM AUTHOR]