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Articles by K. Thenmozhi
Total Records ( 24 ) for K. Thenmozhi
  Padmapriya Praveenkumar , Rengarajan Amirtharajan , K. Thenmozhi and John Bosco Balaguru Rayappan
  With the rabid development of the wireless technology, the gadgets that were once a luxury, have now become a necessity. The wireless technology was first developed for army utilisation. But later, because of the wide applications it had, it became a global obligation. But, today, with the advent of internet, the security of the wireless networks has been at a great stake. And also, the new generation of wireless network demands higher data requirements which is achieved by higher data bits per unit bandwidth because of a variety of multimedia applications, cost efficiency, spectral efficiency and security. In this study all of these challenging requirements are met by Orthogonal Frequency Division Multiplexing (OFDM) along with steganography. It is an attractive and explorative area for the next and future generation of wireless multimedia applications. The major challenging issue in the design of an OFDM transceiver is its high Peak-to-Average Power Ratio (PAPR). In this study, design of an OFDM system adopting Partial Transmit Sequence (PTS) and Selected Mapping (SLM) techniques were concentrated. We analyse the system performance for various values of subcarriers and modulation schemes by computing Complementary Cumulative Distribution Function (CCDF) and analysing the Bit Error Rate (BER). PAPR value is low as the number of subcarriers has been increased. PTS outperforms SLM when complexity is considered and SLM is preferred when the redundant bits in the information are high and data embedding algorithm is included after modulation to ensure wireless security.
  Padmapriya Praveenkumar , G.U. Priyanga , K. Thenmozhi , J.B.B. Rayappan and R. Amirtharajan
  The intellectual growth of computer communication lead to drastic improvement in wireless technology and shrunken the world into palms of the user which paved the path for the security attack issues. The development of the security system became the ultimate. Popular technique widely used in present scenario that provides a better security to secret information is image encryption. Multiple encryption technique has been adopted in this study. The secret image is block shuffled and then chaotic maps such as baker map, skew tent map and Arnold cat map are used to encrypt the image. Further the image is encrypted using Cipher Block Chaining (CBC) to contribute the final encrypted image. Metrics such as horizontal, vertical, diagonal correlation, Number of Changing Pixel Rate (NPCR) and entropy were calculated for various Digital Imaging and Communication in Medicine (DICOM) test images and the performance of the algorithm was analyzed.
  J. Avila and K. Thenmozhi
  Cognitive Radio Networks (CRN), one of the emerging technologies in the wireless communication domain, is primarily used for spectrum sensing and proper allocation of the unused licensed bands to the secondary users without causing any interference to the primary user in a dynamic manner. However, security to the physical layer becomes a major problem here. This study gives a reliable solution to avoid the Physical User Emulation Attack (PUEA) by employing a Pseudo noise sequence (PN) based novel encryption technique. This study brings out the MATLAB simulated BER curves before and after using the proposed algorithm interpreting the error performance. The results prove that the proposed algorithm gives a reliable real time performance.
  Siva Janakiraman , Rengarajan Amirtharajan , K. Thenmozhi and John Bosco Balaguru Rayappan
  In the wake of cyber era, digital crime takes its shape in the schemes of modern warfare piercing existing security system without any collateral damage. The then existent cryptic army was either unable to stop the foes or had won a pyrrhic victory and thus evolved the war veteran, steganography that could withstand any destructive mechanism forced against it. Hence, in this study, three novel steganographic methods have been proposed to enhance the randomness of the mercurial data. All the three methods are implemented using the pixel indicator technology. Method one of the three uses the chosen pixel for guidance and as data channel for embedding. Method two takes a block of three pixels at a time where the first pixel acts as the steering channel while the remaining two become the data channel. Method three is further bifurcated; the first segment of this method involves the size definition within the first four pixels of the image and determination of that type of number i.e., even, prime or other. Depending on the type the channels red, blue or green are chosen as indicators, respectively. The second segment is where the size\value is checked for even parity and odd parity. Depending on its evenness or oddness the combination of data channel for embedding is arranged i.e., size is an even number with an odd parity red is the steering channel while the order of data channels are green and blue. The bifurcation and levels of selections increase the contingency of the embedment while retaining its reticence. Results confirm that the proposed methodology yield lesser error metrics while creating an efficacious channel to secure data transmission.
  J. Avila , B. Vinoth and K. Thenmozhi
  Ever since the human mind gave birth to technology, adopted it and dedicated itself to enhance it for human ease, the need for an efficient technique that supports accelerated data rates is vital. To add on to the scenario, the spectrum utilization which has reached its pinnacle places before us a major challenge. Hence the need for an accomplished and unbiased use of the spectrum has become our main focus. After years of pondering over the above mentioned problems a solution has been arrived named Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM). Efficient error control codes form the basic building blocks of any system designed for a perfectionists requirement and it is these error control codes that enhances the data rate of MB-OFDM system. Rising demands have made single error control codes inefficient. This crisis can be overcome by concatenating error control codes which exhibit consequential improvement in coding gain. This study consolidates MB-OFDM system with following enhancement: the use of error control codes namely turbo codes, Reed Solomon codes and convolution codes in multiband-OFDM system. In addition improvement in spatial diversity is achieved by using Alamouti technique and finally Alamouti code is concatenated with error control codes and results are compared. As a supplement the fast Fourier transform of the multiband OFDM system is replaced by wavelet transform.
  Siva Janakiraman , Jagannathan Chakravarthy , Badrinath Radhakrishnan , K. Thenmozhi , J.B.B. Rayappan and Rengarajan Amirtharajan
  Communication playing the key role of daily lives has created revolutions since the Stone Age. In this fast-paced technological world, the utilization of information has gained towering momentum. Furthermore, information while transmitted over the internet with the swift escalation in the mass media and digital communication technology, the requirement for impregnable covert channel arises especially when critical information has to be communed. Over the years, Information hiding techniques have evolved to conceal any critical data in cover files like images, audios and videos and thus, certifying the genuineness and secrecy of the transmitted data. Steganography is one such method where the very existence of the data in the cover image is hidden and thereby, provides for security by making the hidden data unconceivable. The cover file may include audio, video or image files. In this study, two methods have been proposed to embed image within an image with two and three layers of security, respectively. A decoder circuit is used in one of the layers to embed the data not only in the LSB bits but also in the other bits of the lower nibble. Moreover, two bits of data are embedded in a pixel by changing only one bit of the pixel. These methods show improved security without compromising on the PSNR and MSE values.
  Padmapriya Praveenkumar , K. Thenmozhi , J.B.B. Rayappan and Rengarajan Amirtharajan
  The prospects of the next generation wireless broadband applications will be enhanced by the features like improved Signal to Noise Ratio (SNR) and variable higher data rates. The Orthogonal Frequency Division Multiplexing (OFDM) system offers better tolerance against multipath effects faced by fading channels. Forward Error Correction (FEC) codes meliorate the system performance. In this study, firstly the data is encoded using Convolution encoders with Puncture codes in OFDM system. Then, the secret message is embedded and passed through Rayleigh and Rician fading channels. The BER graph prior and after embedding the confidential data are compared and simulated using BPSK modulation scheme. The system is made more reliable by reducing the redundancy, errors in the signals and making it more secure and robust in fading environment.
  Padmapriya Praveenkumar , R. Deepak , K. Thenmozhi , John Bosco Balaguru Rayappan and Rengarajan Amirtharajan
  In the era of wireless communication, the World Wide Web is the brain child of all the new technological development. This digital world has speeded up the data transfer and communication speed a manifold, creating new goods and services all along. Along with the development of internet, developed ways of hacking, modifying and stealing it also increased. There is an increasing demand to augment the data rates and to provide greater fidelity. Thus, technology provides us the finesse for increasing robustness over fading channels. The most prominent solution for increased speed is OFDM. And the security issues can be taken care of by embedding confidential data after encoding the message using cyclic codes.
  Siva Janakiraman , K.V.Sai Krishna Kumar , R.Rohit Kumar Reddy , A. Srinivasulu , Rengarajan Amirtharajan , K. Thenmozhi and John Bosco Balaguru Rayappan
  The day to day amplification on technology and the demand on shrinking the device sizes reflect in the diminution on memory sizes and constraints on device outlay. In the present times of mass communication with the swift escalating technology, there is a dire necessity for security on the information traversing between authorized individuals. All these factors invite the property of light weightiness and the focused security algorithms such as Hummingbird for devices with humiliated resources. This study present an efficient software implementation of modified Humming Bird algorithm on an 8-bit microcontroller with randomization on sub-key selection based on LFSR. We also do comparative analysis on performance in terms of memory foot print and execution time between our modified one and the original algorithm implementations. The obtained results make it evident that the proposed method raises the complexity significantly without hike in resource consumption and makes it more suitable to provide security in extremely constrained devices.
  J. Avila and K. Thenmozhi
  For high data rate wireless applications over short distances, multiband OFDM proves to be the right contender. The concatenation of error control code for multiband OFDM cognitive radio system is analysed. Reed Solomon code and convolutional code are taken in to account for analysis. From the simulation results it can be inferred that because of the improved coding gain concatenated codes prove to be superior to single codes. As a supplementary, the fast Fourier transform and Inverse fast Fourier transform portion of the multiband OFDM systems are exchanged with the discrete wavelet transform and inverse discrete wavelet transform blocks respectively thus reducing the interferences drastically and as a result the overall bit error rate (BER) gets improved.
  Padmapriya Praveenkumar , K. Thenmozhi , John Bosco Balaguru Rayappan and Rengarajan Amirtharajan
  Improved Signal to Noise Ratio (SNR) and variable higher data rates will pave a way to a brighter future for the next generation broadband applications of wireless communication. The OFDM system tolerates robustness against the multipath effects encountered by the fading channels. Enhanced system is achieved by using Forward Error Correction (FEC) codes. The attrition of errors in signals will increase the reliability of the system. In this study, secret data has been embedded after encoding the data using Convolutional encoders and passed over OFDM system. At the receiver end, Artificial Neural Network (ANN) helps better BER. The signals are passed over an OFDM receiver and decoded using Viterbi decoders.
  Padmapriya Praveenkumar , K. Thenmozhi , J.B.B. Rayappan and Rengarajan Amirtharajan
  Stupendous advances in Digital Communication have brought about the advent of internet culture benefiting the people in many ways. Just as fire is a good servant, but a bad master, so is the case with internet. With internet, stealing and unauthorised usage of data remains unrestrained. In addition, use of high multimedia applications demands for higher data rates. To accommodate the challenging needs of higher data rate requirements, Orthogonal Frequency Division Multiplexing (OFDM) proves to be the propitious solution. Hacking over wireless environment can be staved off by incorporating the emerging information hiding techniques with OFDM system. This study analyses the performance of OFDM system using modulation schemes like Binary Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) and Quadrature Amplitude Modulation (QAM) and then the confidential information is embedded after interleaving and passed over AWGN channel. Interleaving serves two purposes primarily it reduces burst errors and it needs two different keys intact, one to stipulate the scrambling of the data bits and the other to identify the secret data embedding. It is observed from the simulation results that the BER of the system can be improved by rearranging the input data streams through interleaving, thereby reducing the random errors due to noisy wireless channel environment. The BER graph is simulated for various modulation schemes prior to embedding and after embedding the confidential information.
  Padmapriya Praveenkumar , K. Thenmozhi , John Bosco Balaguru Rayappan and Rengarajan Amirtharajan
  Wireless communication is an incipient technique to increase portability, but is inept on grounds of security and capacity. Wireless communication coupled with multiple access techniques help in resolving these issues and aid in providing variable data rates. The security aspects can be palliated by using spread spectrum with information hiding mechanisms. This study analyses confidential data hiding using spread spectrum scheme added to Orthogonal Frequency Division Multiplexing (OFDM) system adopting different modulation schemes. Performance analysis is done with and without confidential data embedding considering Additive White Gaussian Noise (AWGN) channel. Code Division Multiple Access (CDMA) are compared and analysed with Multicarrier CDMA (MC CDMA) schemes using Bit Error Rate (BER) performance.
  C. Lakshmi , K. Thenmozhi , J.B.B. Rayappan and Rengarajan Amirtharajan
  In this study, implied an overture for acquainting Tamil Character which is handwritten. This refers the procedure of converting written Tamil font to printed one since it is a tedious to course the above mentioned owing to its deviated writing manner, dimension, angle of direction etc. Here, scanned images get pre-processed and subdivided into, first, paragraphs, then (paragraph) to lines, then (line) to words and finally (word) to separate glyph. This study coalesces structural plus categorization analysis and is determined to be extra proficient in support of outsized and composite sets. Recognition Efficiency is enhanced and this proposal generates finest outcomes apart from doing better than existing methods. Also this routine can be further extended to other Indian languages as well.
  Padmapriya Praveenkumar , G.S. Hemalatha , Bharathsimha Reddy , K. Thenmozhi , J.B.B. Rayappan and Rengarajan Amirtharajan
  The prerequisite of internet and multimedia communication in the present wireless age is impregnability and higher data rata. In this study, a pragmatic approach was accomplished by the Simulink model of Orthogonal Frequency Division Multiplexing (OFDM) using image steganography incorporating BPSK and QPSK modulation schemes. To contemplate the distortion in the image, the discerning distortion metrics called as Mean Square Error (MSE) and Peak Signal to Noise Ratio (PSNR) were computed. The BER of OFDM system was also analysed.
  Padmapriya Praveenkumar , K. Thenmozhi , J.B.B. Rayappan and Rengarajan Amirtharajan
  We live in an era where hacking and unauthorized access attempts to data are so common. There is a need to secure data before it is transmitted. Addition of overhead bits and modulation techniques decrease the capacity and increase the cost. Both the channel capacity and the cost to set up the communication system have to be optimal. So intimidating is a feature called multiple access used for this purpose. Multiple access also improves capacity by simultaneously transmitting large number of messages. There is very less or no interference between the signals since each of them is polarized orthogonally or encoded using different coding sequences or sent as bursts in different time slots. Particularly Code Division Multiple Access (CDMA) makes it more difficult for the hacker to access the transmitted data. If the message is thrown to all the users only the intended receiver has the same coding sequence to decode it. So, others can’t access the message. Even if the message is detected, use of steganography makes it all the more difficult for the hacker to decode the message. This increases the security multifold. The aesthetic appeal of CDMA and steganography together has revolutionized the present world communication systems. In this study, the performance of CDMA is analysed by embedding confidential information at three levels namely after interleaving, spreading and modulator. The Bit Error Rate (BER) performance comparison graphs with and without information hiding at three levels are analysed using BPSK, QPSK and QAM schemes.
  Padmapriya Praveenkumar , P. Rajalakshmi , G.U. Priyanga , K. Thenmozhi , John Bosco Balaguru Rayappan and Rengarajan Amirtharajan
  Security has become the most indispensible part of any form of communication. There are different ways through which it is brought about, out of which one of the efficient implementation through steganography and encryption. Steganography conceals the existence of a secret message throughout the communication thereby providing enhanced security. In this study, a methodology has been proposed to perform encryption on an image with the help of Secret Steganography Code for Embedding (SSCE) code. A mapping technique has been proposed to combine quantum truth table and LSB based embedding. The SSCE has been employed to provide encryption, followed by quantum table before embedding the secret data. The proposed methodology supports both images and text as cover as well as secret data. In the proposed scheme, embedding has been included with encryption to provide security multifold. The implementation was carried out using Visual Basic. NET and results are presented.
  Padmapriya Praveenkumar , K. Thenmozhi , John Bosco Balaguru Rayappan and Rengarajan Amirtharajan
  Brobdingnagian may be the precise word for the usage of internet and advanced expertise in the globe in our day. Indeed, all sorts of this online communication go hand in hand with the so called major apprehension, information security. Since all kinds of digital files play an imperative role in internet operation, it is indispensable to defend the key features of private communication namely, seclusion, uprightness and legitimacy. This threat, in a roundabout way, has led to the breakthrough of information security rationales. Striking among these are Cryptography and Steganography, primordial skills pursued for the sake of secret sharing. The startling thing is that with the fruition of technology, these are giving prolific outcomes even now. Cryptography possesses such a litheness that its blend, in the company of other fields of study, facilitates offer much more options to explore security issues. This study envisions an inimitable approach to security in the context of encryption and embedding incorporating shuffling, chaotic equations in conjunction with Blowfish encryption algorithm. Here, encryption is performed on images followed by embedding secret data. The latter is done not literally but indirectly. This pitch endows with randomness and security with all the persuasive traits of encryption. Validation is given in terms of Mean Square Error (MSE), Peak Signal to Noise Ratio (PSNR), Relative Entropy (RE), entropy and correlation values. Experimental results are illustrated to vindicate the performance of this objective.
  Padmapriya Praveenkumar , Rengarajan Amirtharajan , K. Thenmozhi and John Bosco Balaguru Rayappan
  Orthogonal Frequency Division Multiplexing (OFDM) has come to the rescue of the bandwidth constraint owing to the burgeoning digital multimedia applications. The serial data is made parallel and transmitted over multiple orthogonal frequencies with bandwidth of each subcarrier considerably lesser than the coherence bandwidth of the channel. This study aims to review the present state of art in Error Correcting Codes (ECC) in OFDM, generated by methods like Convolutional Encoding, using Reed-Solomon Codes and Turbo codes. Furthermore the deployment of Artificial Neural Networks (ANN), to train the system for higher fault tolerance in OFDM is detailed.
  Bakkiam David Deebak , Rajappa Muthaiah , K. Thenmozhi and Pitchai Iyer Swaminathan
  Objective of the study is to study and analyze the dynamic-centric metrics of bandwidth allocation and estimation for wireless networks. We also extend the objective to probe Quality of Service (QoS) provisioning guarantee for infeasible packet routing networking protocols. This study signifies the bandwidth sharing scheme for real time and non-real time based. So far, the researchers have not examined this signification to have a good impact on throughput rate, packet reception rate, packet dropping rate and packet delay. Nowadays, the network technologies have been focused much on dynamic bandwidth allocation for achieving effective bandwidth utilization, good service rate and improving service satisfaction. Thus, we study a lot of routing strategies to analyze the metrics of bandwidth. In the study, we find the convex optimization technique as suitable to enhance the network throughput performance, providing bandwidth issue is negotiated on network.
  Padmapriya Praveenkumar , Rengarajan Amirtharajan , K. Thenmozhi and J.B.B. Rayappan
  This study proposes Orthogonal Frequency Division Multiplexing (OFDM), endorsed by encryption and concatenated Error Correction Codes (ECC). OFDM, as the name suggests exploits the carriers’ orthogonality properties and Frequency Division Multiplexing (FDM) caters to the bandwidth requirements for the broadband applications. To reduce the errors due to the channel noise conditions, concatenated codes utilizing Reed Solomon (RS) codes and convolutional codes are used. Its encoded output is encrypted using the chaotic means to espouse discretion before passing through OFDM channel. Error performance of the scheme is analysed using Additive White Gaussian Noise (AWGN) channel. Comparative graphs are plotted for the performance of Bit Error Rate (BER) on different modulation schemes with different inner and outer code rates. For performance measurements, metrics like BER and Correlation values are computed.
  Padmapriya Praveenkumar , Rengarajan Amirtharajan , K. Thenmozhi and J.B.B. Rayappan
  Information security is a prime concern especially when it comes to business and corporate sectors where off the record information should be given utmost importance. Very cooperative especially to business enterprise, modern day expertise has contributed a lot towards sharing a surreptitious data. The field of wireless communication has surmounted many hurdles in the past few years and is now finally capable of supporting higher data rates thanks to the development of Orthogonal Frequency Division Multiplexing (OFDM). It is the most ideal format for broadband communication to meet its need for higher data rates. This study further augment the usefulness of OFDM communication by making it secure to avert data piracy. This study propose an idea of embedding the secret message at the real part of Inverse Fast Fourier Transform (IFFT) output of OFDM system and performance of the system is examined for various modulations. Thus, this study is a conjunction of wireless and data security which serves the purpose of secret sharing and can be applicable and suitable to entrepreneurial activities.
  Padmapriya Praveenkumar , Rengarajan Amirtharajan , K. Thenmozhi and J.B.B. Rayappan
  Wireless communication with its enhanced efficiency, greater flexibility, mobility and reduced cost has encompassed human needs and sophistications to a greater extent. Several techniques adopted in the wireless standards solely contribute to its heightened demand. Orthogonal Frequency Division Multiplexing (OFDM) is one such technique adopted to provide robust and high speed networks by countenancing signal overlap. The data transmission over wireless, in general, is unsecure and open to the hands of the hackers. A method has to be devised to uniquely identify the copyright owner of the data and prevent the misuse of it. However, on the negative side, the hackers are on par with the experts in this field to combat against piracy. This necessitates the introduction of a method to impart security to the data being transmitted. This study embeds secret data bits in punctured convolutional encoder’s output which are then encrypted using Chaotic means to uphold discretion and then traversed through OFDM system. Integrity is made certain by four-level encryption of secret bits and is stored as key in Cyclic Prefix’s (CP) output. Comparison graphs for the performance of Bit Error Rate (BER) are plotted for different modulation schemes with different rates of punctured convolutional codes. These plots are for puncture patterns with convolutional encoder before and after infixing the secret data. Widespread metrics for performance measurement like BER and correlation values are computed. This estimation reveals the security and arbitrariness of data encryption both with and without embedding the secret.
  Padmapriya Praveenkumar , Rengarajan Amirtharajan , R. Sai Janani , K. Thenmozhi and J.B.B. Rayappan
  There are numerous criteria in running an enterprise. Apart from trading goods and services, or may be both to clients, emphasis should be laid on maintaining the business model that comprises of maintenance of intellectual properties and decisive testimonials as well. In this regard, up to date technological proficiencies be of great assist as everything is now digital and online. Though sound different, technology and administrative terms go hand in hand. Of all one domain that catch the attention instantly is secret sharing and secret communication. This study is one such work. Digital multimedia applications, coming into the limelight in the recent years have impacted the bandwidth requirements and caused an ever soaring demand for broadband wireless application. On the other hand, wireless communication that uses fixed modulation fails to satisfy the needs as its efficiency is stultified by the fading channels. This stydy proposes the adaptive modulation scheme in OFDM (Orthogonal Frequency Division Multiplexing) system to counteract fading in the transmission power and the transfer function of frequency selective channel. The prime aim is to maximise the total capacity and transmit power without vitiating the quality of service at the receiver. It can be achieved by making the system smart and subsume some intelligence into it. We make the system adapt itself to the channel conditions and choose the well-suited service at that instant. Simulation results have made it clear that adaptive modulation in OFDM system offers the choice of modulation and FEC (Forward Error Control Codes) with variable rates. The essence of adaptation is maintained even while embedding in wireless transmission to serve the security purposes. Bit Error Rate (BER) graph plotted prior to embedding is analyzed and compared with the one plotted for embedded data.
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