Now showing items 1-20 of 22
Next Page| Abstract: | A simple approach for accurate determination of the resonant frequencies of microstrip antennas of regular geometries is developed and presented. In this approach, a generalised empirical formula for the computation of effective dielectric permittivity is given which takes into account the ratio of the fringing area to the area of the patch. A correction to the equivalent side length of an equilateral triangular patch, previously published, is modified and a new formula is given. A correction to the effective dimensions of an elliptical microstrip antenna is also carried out. Numerical results obtained for the resonant frequencies of elliptical, circular, rectangular and equilateral-triangular microstrip antennas are in good agreement with the available theoretical and experimental results reported by others. The present approach is more efficient, simpler and more accurate |
| Description: | IEE Proc.-Microw. Antennas Propag., Vol. 145, No. 2, April 1998 |
| URI: | http://dyuthi.cusat.ac.in/purl/4511 |
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| Simple approach ... of microstrip antennas.pdf | (390.7Kb) |
| Abstract: | Analytical expressions for the Green’s function of an annular elliptical ring microstrip antenna (AERMA) are developed and reported. The modal, radiation and input impedance characteristics of the TM, modes are determined from these expressions. The resonant frequencies of odd modes are greater than that of the even modes for all TMnl modes (n = 1, 2, 3, ...) udke elliptical microstrip structures. The radiation pattern and input imedance curves of TMI2 mode on comparison with available experimental result shows good agreement whch provides an independent validation to this technique. The performance of the AERMA is then investigated as a function of thickness and substrate dielectric permittivity. |
| Description: | IEE Proc.-Microw. Antennas Propag., Vol. 146, No. 6, December 1999 |
| URI: | http://dyuthi.cusat.ac.in/purl/4532 |
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| Theoretical inv ... n‘s function technique.pdf | (440.2Kb) |
| Description: | Antennas and Propagation, IEEE Transactions on,VOL 48,issue 4,pp 636 |
| URI: | http://dyuthi.cusat.ac.in/purl/4517 |
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| Comments on “Si ... crostrip Patch Antenna.pdf | (31.94Kb) |
| Abstract: | This paper presents a cascaded 2-2-2 reconfigurable sigma-delta modulator that can handle GSM, WCDMA and WLAN standards. The modulator makes use of a low-distortion swing suppression topology which is highly suitable for wide band applications. In GSM mode, only the first stage (2nd order Σ-Δ ADC) is turned on to achieve 88dB dynamic range with oversampling ratio of 160 for a bandwidth of 200KHz; in WCDMA mode a 2-2 cascaded structure (4th order) is turned on with 1-bit in the first stage and 2-bit in the second stage to achieve 74 dB dynamic range with oversampling ratio of 16 for a bandwidth of 2MHz and a 2-2-2 cascaded MASH architecture with a 4-bit in the last stage to achieve a dynamic range of 58dB for a bandwidth of 20MHz. The novelty lies in the fact that unused blocks of second and third stages can be switched off taking into considerations like power consumption. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8 supply voltage. |
| Description: | SOC Conference, 2007 IEEE International,309-312 |
| URI: | http://dyuthi.cusat.ac.in/purl/4523 |
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| A Triple-Mode F ... dma Wlan Applications.pdf | (557.8Kb) |
| Abstract: | This work presents a wideband low-distortion sigmadelta analog-to-digital converter (ADC) for Wireless Local Area Network (WLAN) standard. The proposed converter makes use of low-distortion swing suppression SDM architecture which is highly suitable for low oversampling ratios to attain high linearity over a wide bandwidth. The modulator employs a 2-2 cascaded sigma-delta modulator with feedforward path with a single-bit quantizer in the first stage and 4-bit in the second stage. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8V supply voltage. Simulation results show that, a peak SNDR of 57dB and a spurious free dynamic range (SFDR) of 66dB is obtained for a 10MHz signal bandwidth, and an oversampling ratio of 8. |
| Description: | Information, Communications & Signal Processing, 2007 6th International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4512 |
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| Wideband Low-Di ... gma-Delta ADC for WLAN.pdf | (274.8Kb) |
| Abstract: | This work presents a triple-mode sigma-delta modulator for three wireless standards namely GSM/WCDMA and Bluetooth. A reconfigurable ADC has been used to meet the wide bandwidth and high dynamic range requirements of the multi-standard receivers with less power consumption. A highly linear sigma-delta ADC which has reduced sensitivity to circuit imperfections has been chosen in our design. This is particularly suitable for wide band applications where the oversampling ratio is low. Simulation results indicate that the modulator achieves a peak SNDR of 84/68/68 dB over a bandwidth of 0.2/3.84/1.5 MHz with an oversampling ratio 128/8/8 in GSM/WCDMA/Bluetooth modes respectively |
| Description: | 10th International Conference on Information Technology |
| URI: | http://dyuthi.cusat.ac.in/purl/4514 |
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| A Triple-mode S ... for Wireless Standards.pdf | (540.2Kb) |
| Abstract: | This paper discusses the implementation details of a child friendly, good quality, English text-to-speech (TTS) system that is phoneme-based, concatenative, easy to set up and use with little memory. Direct waveform concatenation and linear prediction coding (LPC) are used. Most existing TTS systems are unit-selection based, which use standard speech databases available in neutral adult voices.Here reduced memory is achieved by the concatenation of phonemes and by replacing phonetic wave files with their LPC coefficients. Linguistic analysis was used to reduce the algorithmic complexity instead of signal processing techniques. Sufficient degree of customization and generalization catering to the needs of the child user had been included through the provision for vocabulary and voice selection to suit the requisites of the child. Prosody had also been incorporated. This inexpensive TTS systemwas implemented inMATLAB, with the synthesis presented by means of a graphical user interface (GUI), thus making it child friendly. This can be used not only as an interesting language learning aid for the normal child but it also serves as a speech aid to the vocally disabled child. The quality of the synthesized speech was evaluated using the mean opinion score (MOS). |
| Description: | Advances in Human-Computer Interaction Volume 2008, Article ID 597971, 6 pages |
| URI: | http://dyuthi.cusat.ac.in/purl/4527 |
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| Developing a Ch ... Text-to-Speech System.pdf | (1.508Mb) |
| Abstract: | Over-sampling sigma-delta analogue-to-digital converters (ADCs) are one of the key building blocks of state of the art wireless transceivers. In the sigma-delta modulator design the scaling coefficients determine the overall signal-to-noise ratio. Therefore, selecting the optimum value of the coefficient is very important. To this end, this paper addresses the design of a fourthorder multi-bit sigma-delta modulator for Wireless Local Area Networks (WLAN) receiver with feed-forward path and the optimum coefficients are selected using genetic algorithm (GA)- based search method. In particular, the proposed converter makes use of low-distortion swing suppression SDM architecture which is highly suitable for low oversampling ratios to attain high linearity over a wide bandwidth. The focus of this paper is the identification of the best coefficients suitable for the proposed topology as well as the optimization of a set of system parameters in order to achieve the desired signal-to-noise ratio. GA-based search engine is a stochastic search method which can find the optimum solution within the given constraints. |
| Description: | Systems, Man and Cybernetics, 2008. SMC 2008. IEEE International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4516 |
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| GA-based Optimi ... lta Modulator for WLAN.pdf | (234.9Kb) |
| Abstract: | The demand for new telecommunication services requiring higher capacities, data rates and different operating modes have motivated the development of new generation multi-standard wireless transceivers. In multistandard design, sigma-delta based ADC is one of the most popular choices. To this end, in this paper we present cascaded 2-2-2 reconfigurable sigma-delta modulator that can handle GSM, WCDMA and WLAN standards. The modulator makes use of a low-distortion swing suppression topology which is highly suitable for wide band applications. In GSM mode, only the first stage (2nd order Σ-Δ ADC) is used to achieve a peak SNDR of 88dB with oversampling ratio of 160 for a bandwidth of 200KHz and for WCDMA mode a 2-2 cascaded structure (4th order) is turned on with 1-bit in the first stage and 2-bit in the second stage to achieve 74 dB peak SNDR with over-sampling ratio of 16 for a bandwidth of 2MHz. Finally, a 2-2-2 cascaded MASH architecture with 4-bit in the last stage is proposed to achieve a peak SNDR of 58dB for WLAN for a bandwidth of 20MHz. The novelty lies in the fact that unused blocks of second and third stages can be made inactive to achieve low power consumption. The modulator is designed in TSMC 0.18um CMOS technology and operates at 1.8 supply voltage |
| Description: | J Sign Process Syst (2011) 62:117–130 |
| URI: | http://dyuthi.cusat.ac.in/purl/4513 |
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| A Multi-Mode Si ... CDMA WLAN Applications.pdf | (623.2Kb) |
| Abstract: | Considerable research effort has been devoted in predicting the exon regions of genes. The binary indicator (BI), Electron ion interaction pseudo potential (EIIP), Filter method are some of the methods. All these methods make use of the period three behavior of the exon region. Even though the method suggested in this paper is similar to above mentioned methods , it introduces a set of sequences for mapping the nucleotides selected by applying genetic algorithm and found to be more promising |
| Description: | Advances in Computing, Control, & Telecommunication Technologies, 2009. ACT'09. International Conference on,PP 856-858 |
| URI: | http://dyuthi.cusat.ac.in/purl/4522 |
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| Genetic algorit ... hodfor exon prediction.pdf | (321.0Kb) |
| Abstract: | In this paper, an improved technique for evolving wavelet coefficients refined for compression and reconstruction of fingerprint images is presented. The FBI fingerprint compression standard [1, 2] uses the cdf 9/7 wavelet filter coefficients. Lifting scheme is an efficient way to represent classical wavelets with fewer filter coefficients [3, 4]. Here Genetic algorithm (GA) is used to evolve better lifting filter coefficients for cdf 9/7 wavelet to compress and reconstruct fingerprint images with better quality. Since the lifting filter coefficients are few in numbers compared to the corresponding classical wavelet filter coefficients, they are evolved at a faster rate using GA. A better reconstructed image quality in terms of Peak-Signal-to-Noise-Ratio (PSNR) is achieved with the best lifting filter coefficients evolved for a compression ratio 16:1. These evolved coefficients perform well for other compression ratios also. |
| Description: | Communication Control and Computing Technologies (ICCCCT), 2010 IEEE International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4521 |
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| An Improved Tec ... rint Image compression.pdf | (451.8Kb) |
| Abstract: | A Multi-Objective Antenna Placement Genetic Algorithm (MO-APGA) has been proposed for the synthesis of matched antenna arrays on complex platforms. The total number of antennas required, their position on the platform, location of loads, loading circuit parameters, decoupling and matching network topology, matching network parameters and feed network parameters are optimized simultaneously. The optimization goal was to provide a given minimum gain, specific gain discrimination between the main and back lobes and broadband performance. This algorithm is developed based on the non-dominated sorting genetic algorithm (NSGA-II) and Minimum Spanning Tree (MST) technique for producing diverse solutions when the number of objectives is increased beyond two. The proposed method is validated through the design of a wideband airborne SAR |
| Description: | Communication Systems (ICCS), 2010 IEEE International Conference on,PP 109-112 |
| URI: | http://dyuthi.cusat.ac.in/purl/4520 |
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| A Multi-Objecti ... s on Complex Platforms.pdf | (719.4Kb) |
| Abstract: | In symmetric block ciphers, substitution and diffusion operations are performed in multiple rounds using sub-keys generated from a key generation procedure called key schedule. The key schedule plays a very important role in deciding the security of block ciphers. In this paper we propose a complex key generation procedure, based on matrix manipulations, which could be introduced in symmetric ciphers. The proposed key generation procedure offers two advantages. First, the procedure is simple to implement and has complexity in determining the sub-keys through crypt analysis. Secondly, the procedure produces a strong avalanche effect making many bits in the output block of a cipher to undergo changes with one bit change in the secret key. As a case study, matrix based key generation procedure has been introduced in Advanced Encryption Standard (AES) by replacing the existing key schedule of AES. The key avalanche and differential key propagation produced in AES have been observed. The paper describes the matrix based key generation procedure and the enhanced key avalanche and differential key propagation produced in AES. It has been shown that, the key avalanche effect and differential key propagation characteristics of AES have improved by replacing the AES key schedule with the Matrix based key generation procedure |
| Description: | International Conference on VLSI, Communication & Instrumentation (ICVCI) 2011 |
| URI: | http://dyuthi.cusat.ac.in/purl/4519 |
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| Matrix based Ke ... ed Encryption Standard.pdf | (236.1Kb) |
| Abstract: | This paper describes certain findings of intonation and intensity study of emotive speech with the minimal use of signal processing algorithms. This study was based on six basic emotions and the neutral, elicited from 1660 English utterances obtained from the speech recordings of six Indian women. The correctness of the emotional content was verified through perceptual listening tests. Marked similarity was noted among pitch contours of like-worded, positive valence emotions, though no such similarity was observed among the four negative valence emotional expressions. The intensity patterns were also studied. The results of the study were validated using arbitrary television recordings for four emotions. The findings are useful to technical researchers, social psychologists and to the common man interested in the dynamics of vocal expression of emotions |
| Description: | Procedia Engineering 30 (2012) 577 – 583 |
| URI: | http://dyuthi.cusat.ac.in/purl/4529 |
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| A socio friendl ... ysis of emotive speech.pdf | (336.4Kb) |
| Abstract: | In this paper we propose a cryptographic transformation based on matrix manipulations for image encryption. Substitution and diffusion operations, based on the matrix, facilitate fast conversion of plaintext and images into ciphertext and cipher images. The paper describes the encryption algorithm, discusses the simulation results and compares with results obtained from Advanced Encryption Standard (AES). It is shown that the proposed algorithm is capable of encrypting images eight times faster than AES. |
| Description: | Recent Advances in Intelligent Computational Systems (RAICS), 2011 IEEE |
| URI: | http://dyuthi.cusat.ac.in/purl/4518 |
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| Matrix based Cr ... cient image encryption.pdf | (1.210Mb) |
| Abstract: | In a leading service economy like India, services lie at the very center of economic activity. Competitive organizations now look not only at the skills and knowledge, but also at the behavior required by an employee to be successful on the job. Emotionally competent employees can effectively deal with occupational stress and maintain psychological well-being. This study explores the scope of the first two formants and jitter to assess seven common emotional states present in the natural speech in English. The k-means method was used to classify emotional speech as neutral, happy, surprised, angry, disgusted and sad. The accuracy of classification obtained using raw jitter was more than 65 percent for happy and sad but less accurate for the others. The overall classification accuracy was 72% in the case of preprocessed jitter. The experimental study was done on 1664 English utterances of 6 females. This is a simple, interesting and more proactive method for employees from varied backgrounds to become aware of their own communication styles as well as that of their colleagues' and customers and is therefore socially beneficial. It is a cheap method also as it requires only a computer. Since knowledge of sophisticated software or signal processing is not necessary, it is easy to analyze |
| Description: | India Conference (INDICON), 2011 Annual IEEE,PP 1-4 |
| URI: | http://dyuthi.cusat.ac.in/purl/4531 |
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| Jitter measurem ... in the Service Sector.pdf | (206.6Kb) |
| Abstract: | This paper explains the Genetic Algorithm (GA) evolution of optimized wavelet that surpass the cdf9/7 wavelet for fingerprint compression and reconstruction. Optimized wavelets have already been evolved in previous works in the literature, but they are highly computationally complex and time consuming. Therefore, in this work, a simple approach is made to reduce the computational complexity of the evolution algorithm. A training image set comprised of three 32x32 size cropped images performed much better than the reported coefficients in literature. An average improvement of 1.0059 dB in PSNR above the classical cdf9/7 wavelet over the 80 fingerprint images was achieved. In addition, the computational speed was increased by 90.18 %. The evolved coefficients for compression ratio (CR) 16:1 yielded better average PSNR for other CRs also. Improvement in average PSNR was experienced for degraded and noisy images as well |
| Description: | 2012 International Conference on Advances in Computing and Communications |
| URI: | http://dyuthi.cusat.ac.in/purl/4530 |
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| Evolution of Be ... n using Cropped Images.pdf | (393.3Kb) |
| Abstract: | Combinational digital circuits can be evolved automatically using Genetic Algorithms (GA). Until recently this technique used linear chromosomes and and one dimensional crossover and mutation operators. In this paper, a new method for representing combinational digital circuits as 2 Dimensional (2D) chromosomes and suitable 2D crossover and mutation techniques has been proposed. By using this method, the convergence speed of GA can be increased significantly compared to the conventional methods. Moreover, the 2D representation and crossover operation provides the designer with better visualization of the evolved circuits. In addition to this, a technique to display automatically the evolved circuits has been developed with the help of MATLAB |
| Description: | Power, Signals, Controls and Computation (EPSCICON), 2012 International Conference on |
| URI: | http://dyuthi.cusat.ac.in/purl/4525 |
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| A Faster 2D Tec ... Using GeneticAlgorithm.pdf | (190.8Kb) |
| Abstract: | In this paper an attempt has been made to determine the number of Premature Ventricular Contraction (PVC) cycles accurately from a given Electrocardiogram (ECG) using a wavelet constructed from multiple Gaussian functions. It is difficult to assess the ECGs of patients who are continuously monitored over a long period of time. Hence the proposed method of classification will be helpful to doctors to determine the severity of PVC in a patient. Principal Component Analysis (PCA) and a simple classifier have been used in addition to the specially developed wavelet transform. The proposed wavelet has been designed using multiple Gaussian functions which when summed up looks similar to that of a normal ECG. The number of Gaussians used depends on the number of peaks present in a normal ECG. The developed wavelet satisfied all the properties of a traditional continuous wavelet. The new wavelet was optimized using genetic algorithm (GA). ECG records from Massachusetts Institute of Technology-Beth Israel Hospital (MIT-BIH) database have been used for validation. Out of the 8694 ECG cycles used for evaluation, the classification algorithm responded with an accuracy of 97.77%. In order to compare the performance of the new wavelet, classification was also performed using the standard wavelets like morlet, meyer, bior3.9, db5, db3, sym3 and haar. The new wavelet outperforms the rest |
| Description: | Power, Signals, Controls and Computation (EPSCICON), 2012 International Conference on,pp 1-5 |
| URI: | http://dyuthi.cusat.ac.in/purl/4526 |
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| Towards the dev ... for ECG classification.pdf | (387.0Kb) |
| Abstract: | Adaptive filter is a primary method to filter Electrocardiogram (ECG), because it does not need the signal statistical characteristics. In this paper, an adaptive filtering technique for denoising the ECG based on Genetic Algorithm (GA) tuned Sign-Data Least Mean Square (SD-LMS) algorithm is proposed. This technique minimizes the mean-squared error between the primary input, which is a noisy ECG, and a reference input which can be either noise that is correlated in some way with the noise in the primary input or a signal that is correlated only with ECG in the primary input. Noise is used as the reference signal in this work. The algorithm was applied to the records from the MIT -BIH Arrhythmia database for removing the baseline wander and 60Hz power line interference. The proposed algorithm gave an average signal to noise ratio improvement of 10.75 dB for baseline wander and 24.26 dB for power line interference which is better than the previous reported works |
| Description: | 2012 IEEE International Conference on Advanced Communication Control and Computing Technologies (ICACCCT) |
| URI: | http://dyuthi.cusat.ac.in/purl/4515 |
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| ECG Noise Remov ... Mean Square Algorithm.pdf | (1.174Mb) |
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