Informatics Publishing Limited

K. Kandasamy ¹, M. Rajaram ²

Affiliations
1 Department of Electronic and Communication Engineering, University College of Engineering, Villupuram-103, IN
2 Anna University, Chennai-25, IN

Abstract

This dissertation discusses about the application of a SEPIC DC-DC converter for a permanent magnet brushless DC motor (PMBLDCM) drive, run by single phase AC mains as single stage power factor correction fed through double bridge rectifier. A three phase voltage source inverter is used as an electronic commutator to operate the permanent magnet brushless DC motor. The advantage of these motors is the removal of brushes, leading to eliminate many problems associated with brushes. The scope of this project is in the use of PMBLDC motor as a drive for the compressor of air-conditioners, fans etc. The switch control separates the two procedures, adjustment of SEPIC converter, and regulation of speed can respond immediately during transient commutation and robustness can be improved and thereby the performance. The proposed permanent magnet brushless DC motor drive is designed and modeled, and its performance is evaluated in MATLAB-SIMULINK.

Keywords

SEPI Converter, Powerfactor PF Correction (PF), Permanent-Magnet (PM) Brushlessdcmotor (PMBLDCM), Voltage Control, Voltage-Source Inverter (VSI).

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M. Rajaram ¹, R. Jegan ², Thirumurgan Thirumurgan ², V. Sumathy ³

Affiliations
1 Park College of Engineering and Technology, Kaniyur, Coimbatore – 641659, Tamil Nadu, IN
2 Department of ECE, Park College of Engineering and Technology, Kaniyur, Coimbatore – 641659, Tamil Nadu, IN
3 Government College of Technology, Coimbatore – 641013, Tamil Nadu, IN

Abstract

Traditionally, real-time systems are built for avery small set of mission-critical applications like space crafts, avionics and other distributed control systems. The various steps in building such systems include, characterizing the workload, designing scheduling algorithms and performing schedulability analysis and Conventional teaching methodologies for real-time systems have primarily focused on these topics and the choice is completely justified for the targeted traditional real-time systems. However with the evolution of small scale real-time embedded systems like cell phones, PDAs, sensor motes and other portable control systems primarily driven by a Real-Time Operating System (RTOS), the conventional teaching methods fall short in several ways. This is because, building such real-time embedded systems poses certain different design and implementation challenges branching out of the severe resource constraints that these devices should operate under. In order to keep pace with these changing trends, we have enhanced our real-time systems course in two different ways. First, we have included the relevant topics like compiler-level and operating systems-level energy aware real-time scheduling algorithms and further developed corresponding assignments and projects to reinforce student learning in these topics. We present some of these details here. Secondly, we have developed a series of laboratory experiments based on commercial RTOSs which give students a rich hands-on experience in building real-time embedded systems We have tried two different RTOSs namely, RT-Linux and VxWorks in two consecutive years. In this paper, we present the similarities and differences between two the RTOS platforms and their impact on student learning.

Keywords

Real-Time Systems, Embedded Systems, Kernel Programming, RTLinux, VxWorks, and Scheduling.

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M. Rajaram ¹, D. Thilagavathy ²

Affiliations
1 Govt College of Engg, Thirunelveli, IN
2 Adhiyamaan College of Engg, Hosur, IN

Abstract

Many emerging network applications are based upon a group communication model. In a peer-to-peer or ad-hoc network which do not have a previously agreed upon common secret key,communication is susceptible to eavesdropping, Hence a secure distributed group key agreement is required to establish and authenticate a common group key for secure and private communication. This paper presents an authenticated distributed collaborative key agreement for dynamic peer groups. The protocol is distributed in nature in which there is no centralized key server, collaborative in nature in which the group key is contributory,dynamic in nature in which existing members may leave the group while new members may join. Instead of performing individual rekeying an interval-based approach is used. The Queue-batch algorithm used for rekeying substantially reduces the computation and communication cost. Key authentication provided focuses on security improvement.

Keywords

Authentication, Dynamic Peer Groups, Group Key Agreement, Rekeying, Secure Group Communication, Security.

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S. Suresh Kumar ¹, M. Rajaram ¹

Affiliations
1 Anna University, Chennai, IN

Abstract

Low-density parity-check with Length-compatible and low error floors (LDPC-LCLEF) on the binary symmetric channel is presented in this paper. These codes can support a wide range of lengths for a given rate and also the Tanner graphs are free of small trapping sets. This can be obtained by applying the schemes of shortening and puncturing to good LDPC codes and the trapping sets are selected using the trapping set ontology based on their relative harmfulness for the given decoding algorithm. The conventional approach does not guarantee to have a good performance as the degree distributions may be wildly varied. In this paper, a modified algorithm is presented to generate LDPC codes of a given rate with almost their degree distributions are same as the mother code degree distribution. Also the relative harmfulness for different trapping sets are evaluated and decoding failures of one trapping set in presence or absence of other trapping sets are analyzed. To facilitate this discussion, a new description of structured LDPC codes with arrays of permutation matrices as parity-check matrices is given. Numerical results show that the LDPC code constructed by this approach performed much better than the conventional approach.

Keywords

LDPC Codes, Tanner Graph, TSO, Mother Code.

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P. Sivakumar ¹, K. Magueswary ², M. Rajaram ³

Affiliations
1 ECE Department of S.K.P. Engineering College, Thiruvannamalai, IN
2 S.K.P. Engineering College, IN
3 Anna University of Technology, Thirunelveli, IN

Abstract

In this letter, analyze the satellite images by using discrete wavelet transform and singular value decomposition. The input image is decomposed into the four frequency sub bands by using DWT and estimates the singular value matrix of the low–low sub band image and then it reconstructs the enhanced image by applying inverse DWT. The technique is compared with conventional image equalization techniques such as standard general histogram equalization and local histogram equalization as well as state-of-theart techniques such as brightness preserving dynamic histogram equalization. The experimental results show the superiority of the proposed method over conventional methods.

Keywords

Discrete Wavelet Transform, Image Equalization, Satellite Image Contrast Enhancement.

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P. Pabitha ¹, A. M. Shobana Priya ¹, S. Nishanthi ², M. Swarnamukhi ¹, M. Rajaram ³

Affiliations
1 Department of Computer Technology, Anna University, Chennai, IN
2 Department of Computer Technology, Anna University, Chennai, IN
3 Anna University of Technology, Tirunelveli, Tamil Nadu, IN

Abstract

Semantic Web is the major research of W3C to create web of resources by giving well defined meaning to the information, so that computer can understand. Ontology is the framework for organizing information in Semantic web. The knowledge representation language, OWL helps in creating ontology quickly and also makes the system to automatically process the information in web. The Unified Modelling Language (UML) is used in object-oriented developments and information system and help the developers to create and view the application visually. Several tools are available for designing UML models but the main drawback is that it lacks in semantics. So in order to bring Semantics, UML models are converted to OWL because common features available between UML and Ontology-based languages. During conversion, problems like inconsistency and redundancy in UML reflect in OWL, so that external OWL reasoner is needed to find the inconsistency. In order to create consistent OWL, we present an approach of converting class diagram to intermediate DL statements and find the inconsistency using the reasoning properties. The inconsistency is said to be there when at least any one of the reasoning properties is not satisfied to the obtained set of Description logic statements of the class diagram. After detection, only consistent DL statements are mapped to OWL which results in consistent OWL.

Keywords

Description Logic, First Order Logic, Ontology, Semantic web, Unified Modeling Language, Web Ontology Language.

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S. N. Sivanandham ¹, M. Rajaram ², S. Latha Shanmugavadivu ³

Affiliations
1 Akshya College of Engineering, Coimbatore, IN
2 EEE Department, Govt. College of Engg., Tirunelveli, IN
3 ECE Dept., Tamilnadu College of Engg., CBE, IN

Abstract

Phishing is an emerging type of social engineering crime on the Web. Most phishers initiate attacks by sending emails to potential victims. These emails lure users to access fake websites, and induce them to expose sensitive and/or private information. The rapid development and evolution of phishing techniques pose a big challenge in Web identity security for computer science researchers in both academia and industry. All phishing attacks spoof users from the visual level and semantic level, i.e., they make the appearances of web pages look similar to the real ones and make the web links and web page contents semantically related to the real ones. In this work, we evaluate visual features that are completely from the computer screen. After the fake page is got through web cache, we check each cache file in the cache directory through phishing. Caching is a technique first used by memory management to reduce bus traffic and latency of data access. With the significant increase of Web traffic, caching techniques are applied to Web caching to reduce network traffic, user-perceived latency, and server load by caching the documents in local proxies. In this work, analization of both advantages and disadvantages of some current Web cache replacement algorithms including lowest relative value algorithm, least weighted usage algorithm and least unified-value (LUV) algorithm is done. Based on our analysis, we proposed a new algorithm, called least grade replacement (LGR), which takes recency, frequency, perfect-history, and document size into account for Web cache optimization..We use web caching techniques to assess the visual features’ similarity. We further convert the retrieved web pages into images and use EMD to calculate their similarity to the protected web pages. Our experiments show that this method is superior to all other visual assessment methods.

Keywords

Phising, Web Caching, Least Grade Replacement Algorithm, Prefetching, Parsing, EMD.

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