M Tech Dissertations
Permanent URI for this collectionhttp://drsr.daiict.ac.in/handle/123456789/3
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Item Open Access Exact algorithm for segment based sequence alignment(Dhirubhai Ambani Institute of Information and Communication Technology, 2015) Tailor, Divyesh; Divakaran, SrikrishnanIn bioinformatics, proteins, large biological molecules consisting long chain of amino acids, are described by a sequence of 20 amino acids. To analyze these protein sequences pairwise alignment is being used, which identify regions of similarity that may be a result of structural, functional and/or evolutionary relationship between them. Traditional pairwise alignment algorithms work on residue level; it does not account structural or functional information that protein carries. A new approach for protein sequence analysis is being proposed here, pairwise alignment of two protein sequences based on segments. Segments of the sequences can be formed on the basis of protein feature, i.e., functional sites or secondary structure of the protein. Each segment carries a type and weight for the alignment process. Algorithm should align two sequences such that segments with weight higher than threshold value must align with the similar type of segment and score for the alignment must be maximal for given scoring function. Here, we are proposing a generic framework to understand, explore and experiment proteins based on their features, i.e. structure, function, and evolution.Item Open Access Human action recognition in video(Dhirubhai Ambani Institute of Information and Communication Technology, 2011) Kumari, Sonal; Mitra, Suman K.Action recognition is a central problem in computer vision which is also known as action recognition or object detection. Action is any meaningful movement of the human and it is used to convey information or to interact naturally without any mechanical devices. It is of utmost importance in designing an intelligent and efficient human–computer interface. The applications of action recognition are manifold, ranging from sign language through medical rehabilitation to virtual reality. Human action recognition is motivated by some of the applications such as video retrieval, Human robot interaction, to interact with deaf and dumb people etc. In any Action Recognition System, a video stream can be captured by using a fixed camera, which may be mounted on the computer or somewhere else. Then some preprocessing steps are done for removing the noise caused because of illumination effects, blurring, false contour etc. Background subtraction is done to remove the static or slowly varying background. In this thesis, multiple background subtraction algorithms are tested and then one of them selected for action recognition system. Background subtraction is also known as foreground/background segmentation or background segmentation or foreground extraction. These terms are frequently used interchangeably in this thesis. The selection of background segmentation algorithm is done on the basis of result of these algorithms on the action database. Good background segmentation result provides a more robust basis for object class recognition. The following four methods for extracting the foreground which are tested: (1) Frame Difference, (2) Background Subtraction, (3) Adaptive Gaussian Mixture Model (Adaptive GMM) [25], and (4) Improved Adaptive Gaussian Mixture Model (Improved Adaptive GMM) [26] in which the last one gives the best result. Now the action region can be extracted in the original video sequences with the help of extracted foreground object. The next step is the feature extraction which deals with the extraction of the important feature (like corner points, optical flow, shape, motion vectors etc.) from the image frame which can be used for tracking in the video frame sequences. Feature reduction is an optional step which basically reduces the dimension of the feature vector. In order to recognize actions, any learning and classification algorithm can be employed. The System is trained by using a training dataset. Then, a new video can be classified according to the action occurring in the video. Following three features are applied for the action recognition task: (1) distance between centroid and corner point, (2) optical flow motion estimation [28, 29], (3) discrete Fourier transform (DFT) of the image block. Among these the proposed DFT feature plays very important role in uniquely identifying any specific action from the database. The proposed novel action recognition model uses discrete Fourier transform (DFT) of the small image block.For the experimentation, MuHAVi data [33] and DA-IICT data are used which includes various kinds of actions of various actors. Following two supervised recognition techniques are used: K-nearest neighbor (KNN) and the classifier using Mahalanobis metric. KNN is parameterized classification techniques where K parameter is to be optimized. Mahalanobis Classifier is non-parameterized classification technique, so no need to worry about parameter optimization. To check the accuracy of the proposed algorithm, Sensitivity and False alarm rate test is performed. The results of this tests show that the proposed algorithm proves to be quite accurate in action recognition in video. And to compare result of the recognition system confusion matrices are created and then compared with other recognition techniques. All the experiments are performed in MATLAB®.
Item Open Access State space based channel modelling(Dhirubhai Ambani Institute of Information and Communication Technology, 2010) Nema, Swati; Chakka, VijaykumarxAbstract: An efficient channel estimation of single-input single output (SISO)/multiple-input multiple-output (MIMO) wireless channel is required for analysis, prediction, fault detection, channel equalization and optimization. This thesis presents a modified recursive MIMO Output-Error State Space Model Identification (MOESP) technique by using fast Givens transformations for LQ update and Lanczos algorithm with modified partial orthogonalization for singular value decomposition (SVD) update. It is based on one of the Subspace System Identification (SSI) technique known as MOESP method. Fast Givens transformation requires 4m multiplications which are less as compared to Givens rotations, as it requires 6m multiplications where m is size of the input vector. Lanczos algorithm with modified partial orthogonalization is applied thereby minimizing the number of vectors to be reorthogonalized for finding the basis for Krylov subspace in the SVD update. Complexity involved in modified partial orthogonalization is O(k:p)3. In existing recursive technique, more number of vectors needs to be orthogonalized by selective orthogonalization method according to the simulation results. Hence, proposed technique offers less complexity and is used for model identification of slow SISO/MIMO wireless channels.Item Open Access Executable specification design and simulation of OFDM based communication system(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Sa, Sudhir Kumar; Dubey, RahulThe communication system using the OFDM principle is today one of the most important application in communication field. This system has various applications from broadband to 3G and digital TV to Radio LANs. This master’s thesis project deals with the implementation of certain specification, algorithmic exploration for WVAN (wireless video area network) in Simulink®. The implemented model and its specification is the reference for the hardware designing and verification. The model used in OFDM based QPSK/16-QAM modulated communication system for the WHD WVAN standard at the High Rate Physical (HRP) layer. This thesis project describes the functionality of the various communication blocks and the method of data transmission through these blocks. The main purpose of this model is to calculate the BER (Bit Error Rate). The final design which supports the different HRP mode for different code rate and different Modulation scheme can take different length of sub-packets which depends on the HRP mode of Transmission. This model also implements the radix-2 FFT algorithm for fixed point FFT processor. Since the FFT processor cannot be used standalone, so in this thesis it is employed in an OFDM Transmitter and Receiver. The goal of this report is to outline the knowledge gained during the master’s thesis project, to describe a design methodology for the OFDM based communication system for high throughput and best error protection. The functionality of each block of the communication system is written in „C‟ code and the output data of each block of Simulink Model is compared to 'C' code written output for the same input.Item Open Access Design and implementation of 128-point fixed point streaming FFT processor for OFDM based communication system(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Verma, Sunil Kumar; Dubey, RahulFast Fourier Transform (FFT) processors are today one of the most important blocks in communication systems. They are used in every communication system from broadband to 3G and digital TV to Radio LANs. This master’s thesis project deals with the pipelined, radix-2 algorithmic exploration and the hardware solution for the FFT processor with the FFT size of 2N points, the selection of the scaling schemes based on application requirement is discussed. The designed architecture is functionally verified in Simulink® and the Xilinx® ISE simulator. How to encapsulate the C++ coded algorithms or functions into the Simulink. This FFT processor is used in OFDM based BPSK modulated communication system for the WHD WVAN standard at the Low Rate Physical (LRP) lay. This thesis project presents the design of the 128 point fixed–point F streaming processor. The final architecture used is the SDF (single path with delay feedback) that implements the radix-2 FFT algorithm. Since the FFT processor can’t be used standalone, so in this thesis it is employed in an OFDM Transmitter and the performance is measured for SNR over a range of PAPRs. The goal of this report is to outline the knowledge gained during the master’s thesis project, to describe a design methodology for the fixed point pipelined FFT processors, the scaling choices and how to encapsulate the existing C code into the Simulink environment to measure the performance of fixed-point systems.Item Open Access 6bit 800 MHz time-interleaved analog to digital converter based on successive approximation in 65 nm standard CMOS process(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Salimath, Arunkumar; Nagchoudhuri, Dipankar; Mandal, Sushanta KumarHigh-speed analog-to-digital converters (ADCs) with resolutions of 6 bits find wide application in instrumentation, wireless systems, optical communication. This dissertation presents a 6 bit, 8 channel Time-Interleaved ADC based on Successive Approximation that performs analog processing only by means of open-loop circuits that are fully differential, thereby achieving a high conversion rate. The work involves the design of a charge redistribution hybrid-DAC, low offset comparator, shift register based phase generator and the SAR Logic. Designed in 65 nm Standard CMOS STMicroelectronics Process, across all the PVT corners, the ADC achieves SNDR of 36 dB and SFDR of 43 dBFS at 800 MHz sampling rate with low input frequencies. When the input frequency is at 300 MHz the SNDR drops to 32.6 dB. The converter draws an average power of 13.5 mW from a 1.2 V supply.Item Open Access Pulse shaping design for PAPR reduction in OFDM(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Jain, Akansha; Vijaykumar, ChakkaFuture mobile communications systems reaching for ever increasing data rates require higher bandwidths than those typical used in todays cellular systems. By going to higher bandwidth the (for low bandwidth) at fading radio channel becomes frequency selective and time dispersive. Due to its inherent robustness against time dispersion Orthogonal Frequency Division Multiplex (OFDM) is an attractive candidate for such future mobile communication systems. OFDM partitions he available bandwidth into many subchannels with much lower bandwidth. Such a narrowband subchannel experiences now almost at fading channel. However, one potential drawback with OFDM modulation is the high Peak to Average power Ratio (PAPR) of the transmitted signal: The signal transmitted by the OFDM system is the superposition of all signals transmitted in the narrowband subchannels. The transmit signal has then due to the central limit theorem a Gaussian distribution leading to high peak values compared to the average power. system design not taking this into account will have a high clip rate. Each signal sample that is beyond the saturation limit of the power amplier suersither clipping to this limit value or other non- linear distortion, both creating additional bit errors in the receiver. One possibility to avoid clipping is to design he system for very high signal peaks. However, this approach leads to very high power consumption (since the power amplifier must have high supply rails) and also complex power amplifiers. The preferred solution is therefore to apply digital signal processing that reduces such high peak values in the transmitted signal thus voiding clipping. These methods are commonly referred to as PAPR reduction. APR reduction methods can be categorized into transparent methods here the receiver is not aware of the reduction scheme applied by the transmitter and on-transparent methods where the receiver needs to know the PAPR algorithm applied by the transmitter. This master thesis would focus on transparent PAPR reduction algorithms. The pulse shaping mechanism is used to reduce PAPR. he ct is analyzed in terms of BER.Item Open Access Design of CDMA transmitter and three finger rake receiver(Dhirubhai Ambani Institute of Information and Communication Technology, 2009) Pateriya, Bhavana; Dubey, RahulAs cellular wireless communication becomes a worldwide communication standard, it is important in studying how data communications happens in a cellular system. In this Thesis work CDMA transmitter and receiver have been designed including the communication channel which include effects of multipath fading and noise. Effectiveness of rake receiver have been verified for varying SNR and with varying the number of fingers. Also the functionality of each block is analyzed.