Informatics Publishing Limited

A. Vani ¹, D. Sreenivasa Rao ²

Affiliations
1 ECE Department, Chaitanya Bharathi Institute of Technology, Hyderabad, Andhra Pradesh, IN
2 ECE Department, Jawaharlal Nehru Technological University, Hyderabad, Andhra Pradesh, IN

Abstract

Ad hoc wireless networks are infrastructure less networks and formed by mobile nodes. These networks are gaining popularity because of low cost mobiles devices and its ability to provide instant wireless networking capabilities. The communication in ad hoc wireless networks functions properly only if the participating nodes cooperate in routing without any malicious intention. But the ad hoc wireless networks are vulnerable to various attacks because of its features like continuous changing topology, resource constraints and unavailability of any centralized infrastructure. Many denial of service type of attacks are possible in ad hoc wireless networks and one of these types of attack is Flooding attack in which malicious node sends the useless packets to consume the valuable network resources. Flooding attack is possible in all almost all on demand routing protocols. Due to this flooding attack the interruption of the network is caused and hence availability of the network service is reduced. The current solutions for these types of attacks are mainly cryptographic, which suffer from heavy computational complexity. In this paper RREQ Flooding attack is detected based on Signal strength and time threshold is used to prevent the flooding attack. The performance of the proposed technique is tested in an On-Demand routing protocol(AODV).The results shows that the proposed techniques reduces the effect of the attack by increasing the packet deli vary ratio.

Keywords

Ad Hoc Wireless Networks, Availability, Security, Flooding Attack.

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V. S. Giridhar Akula ¹, D. Sreenivasa Rao ², S. Sravanthi ²

Affiliations
1 Avanthi's Scientific Technological and Research Academy, IN
2 ASRA, Hyderabad, IN

Abstract

Optical character recognition (OCR) refers to a process whereby printed documents are transformed into ASCII files for the purpose of compact storage, editing, fast retrieval, and other file manipulations through the use of a computer. The principle motivation for the development of OCR Systems is the need to cope with the enormous flood of paper in the form of documents, bank cheques, commercial forms, government records, credit card imprints and mail sorting, generated by expanding technological society.
A method has been developed for single font clear printed documents. This system is primarily designed for Telugu and used the Uniform Sampling Method as the basis for extraction of low-level, structural and stroke-type features and also used the nearest neighbor classifier for classification. The accuracy rate was 96%. The Objective of the current project is to improve the accuracy using different types of hybrid classifiers. This algorithm used segmentation process to isolate words. In this process the process of clipping has been applied to by deleting al zero rows and columns of the image matrix. K-means clusting algorithm is used to determine cluster k and centroids.

Keywords

Nearest Neighbor, K Means Algorithm, Centroids, Filters, Mmse, Skewing, Clipping, Training Patterns, Feature Extraction, Veronoi Diagram, Uniform Sampling.

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A. Srilakshmi ¹, N. V. Koteswara Rao ², D. Sreenivasa Rao ³

Affiliations
1 Vasavi College of Engineering, ECE department, Hyderabad, IN
2 CBIT, Hyderabad, IN
3 JNTUH, Hyderabad, IN

Abstract

A polyhedron shaped annular ring slot antenna is presented. A simple 50 ohms Microstrip line is used to excite the slot. Parametric Design and Analysis is carried out with permutations of the feed length from edge to the centre of annular ring. RT-duriod substrate is used because of its high directivity and high power radiation.

Keywords

Microstrip Antenna, Wideband, Annular Slot

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D. Sreenivasa Rao ¹, Ch. Jessy Beulah ¹, G. Kumar Chaitanya ¹, G. Tataiah Babu ¹, A. S. Chalapathi Rao ¹, G. Vamsi Krishna ¹

Affiliations
1 Department of ECE, St. Ann’s College of Engg and Tech., JNTUK, Chirala, IN

Abstract

Orthogonal frequency division multiplexing provides strong robustness against inter carrier interference and also it provides good performance in frequency selective channels by adaptation techniques to estimate channel quality. An important parameter for calculating the channel performance is by signal to noise ratio (SNR) .I n this paper, we propose a novel for SNR estimation using synchronization preambles for rician fading channels. The preambles of periodic structure are used for efficient calculation for SNR estimation. The proposed estimator performance is compared with previous estimators and the proposed estimator is robust against frequency selectivity in the channel.

Keywords

Inter Symbol Interference (ISI), Channel State Information (CSI), Cramer-Rao Bound (CRB), Fast Fourier Transform (FFT), PS Estimator.

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