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Rao D.S.,GMRIT | Hency V.B.,Vellore Institute of Technology
Journal of Telecommunication, Electronic and Computer Engineering | Year: 2016

IEEE 802.11 based Wireless Local Area Networks (WLANs) have emerged as a popular candidate that offers Internet services for wireless users. The demand of data traffic is increasing every day due to the increase in the use of multimedia applications, such as digital audio, video, and online gaming. With the inclusion of Physical Layer (PHY) technologies, such as the OFDM and MIMO, the current 802.11ac WLANs are claiming Gigabit speeds. Hence, the existing Medium Access Control (MAC) must be in a suitable position to convert the offered PHY data rates for efficient throughput. Further, the integration of cellular networks with WLANs requires unique changes at MAC layer. It is highly required to preserve the Quality of Service (QoS) in these scenarios. Fundamentally, many QoS issues arise from the problem of effective Radio Resource Management (RRM). Although IEEE 802.11 has lifted PHY layer aspects, there is a necessity to investigate MAC layer issues, such as resource utilization, scheduling, admission control and congestion control. In this survey, a literature overview of these techniques, namely the resource allocation and scheduling algorithms are briefly discussed in connection with the QoS at MAC layer. Further, some anticipated enhancements proposed for Multi-User Multiple-Input and Multiple-Output (MU-MIMO) WLANs are discussed.

Nagaraj S.,GMRIT | Raju G.S.V.P.,Andhra University
International Journal of Security and its Applications | Year: 2016

The Cryptographic systems need a secret key or a random number must be necessarily tied to an individual through a unique identifier. This unique identifier definitely might exist a globally user id or biometric data [2]. In this paper we combined biometric with cryptography in which the intensity of each pixel of iris is changed into the elliptic curve and encrypted using ECC. The receiver end original image is recovered by using their decryption and authentication [8] is performed using ECDSA. The proposed technique is implemented for BMP images. We can enroll and add the number of images for authentication. It has been also performed more security if the image is recovered without being any side channel attack. © 2016 SERSC.

Chandramouli S.,GMRIT | Chandramouli S.,Andhra University | Malleswararao P.,Andhra University
International Journal of Engineering and Technology | Year: 2011

The history of water supply and distribution is as old as the history of civilization. In the present society, water supply system has become an important and necessary element. It also gives an indication of level of advancement of society. Water Distribution Network (WDN) is an important component of water supply system which contributes to nearly 70% of the total cost. Optimal design of water distribution network is the aim of any agency dealing with water supply distribution. Consideration of reliability in water distribution networks has been received increasing attention over the past few years. In the present research work, the main focus is on to develop a new parameter for assessing the overall network reliability using fuzzy logic concepts based on the excess pressures available at the demand nodes and to be incorporated in the optimal design and to incorporate this parameter in a two objective optimization model for design of water distribution network using the combination of Genetic Algorithms and EPANET tool kit in the MATLAB environment. The best range of excess of minimum residual pressures is considered in the present study in such a way that the reliability of the network is maximum. The proposed methodology is applied on a two loop gravity network which is referred by most of the researchers. 54 optimal solutions are identified for the network. The Network Reliability Parameter (NRP), Cost Reliability Ration (CRR) and Cost per Unit Reliability and Unit Length (CURUL) parameters are used to compare the results with the previous researchers. It is found that the present study shows better results of when comparing with the results of the previous researchers.

Biodiesel is as an attractive alternat ive fuel for replacement of conventional diesel with small or no changes made to the original design of the engine. 100% replacement entails some problems such as excess Nitrogen Oxide (NOx) generation in the exhaust gases and crankcase oil dilution. Biodiesel made from non-edible oils is a safer choice. Mahua methyl ester (MME) biodiesel is one of the many fuels receiving attention as an alternative fuel for diesel engines, and carries religious significance for being used in temples. Much work and research have been carried out on a Direct Injection (DI) diesel engine with biodiesel and additives. Research in biodiesel acknowledges its advantages and it is envisaged that the emissions can be substantially reduced. Biodiesel is an oxygenated fuel containing approximately 11% of O2 in its molecular structure. This may lead to the release of more NOx in the exhaust gas. In this study, an effort has been made to reduce crank case oil dilution and NOx emission by adopting an Indirect Diesel Injection (IDI) engine. Combustion phenomena were studied and emissions were compared using biodiesel with methyl alcohol as an additive. The aim of the current work is to investigate the emission characteristics of an IDI engine fuelled with Mahua methyl ester (MME) along with Methanol (M) additive blends with an attempt to reduce NOx, HC, CO and smoke emissions employing the concept of low temperature combustion because of methanol's higher latent heat. A four-stroke single-cylinder, forced air and oil cooled IDI diesel engine was used for the investigation. Smoke, NOx, carbon monoxide (CO) and carbon dioxide (CO2) emissions were recorded and various engine performance parameters were measured. A comparative study was conducted using Petro diesel, biodiesel and additive blends of biodiesel on an IDI diesel engine. Mahua methyl ester (MME) was used with additive methanol in different proportions such as 1%, 2%, 3%, 4% and 5% and was tested at different loads in an IDI diesel engine. The performance and emissions of the engine using biodiesel with the additive was compared with an engine with neat diesel operation: 57% HC, 20% CO, 14% NOx, 27% smoke reductions were observed at 3% methanol additive at maximum opted load (2.70 kW and 1500 rpm) operation of the engine. © 2014 Taylor & Francis.

Biswal B.,GMRIT | Behera H.S.,VSSUT | Bisoi R.,Soa University | Dash P.K.,Soa University
Swarm and Evolutionary Computation | Year: 2012

This paper presents a new approach for processing various non-stationary power quality waveforms through a Fast S-Transform with modified Gaussian window to generate timefrequency contours for extracting relevant feature vectors for automatic disturbance pattern classification. The extracted features are then clustered using Bacterial Foraging Optimization Algorithm (BFOA) based Fuzzy decision tree to give improved classification accuracy in comparison to the Fuzzy decision tree alone. To circumvent the problem of premature convergence of BFOA and to improve classification accuracy further, a hybridization of BFOA (Bacterial Foraging Optimization Algorithm) with another very popular optimization technique of current interest called Differential Evolution (DE) is presented in this paper. For robustness the mutation loop of the DE algorithm has been made variable in a stochastic fashion. This hybrid algorithm (Chemotactic Differential Evolution Algorithm (CDEA)) is shown to overcome the problems of slow and premature convergence of BFOA and provide significant improvement in power signal pattern classification. © 2011 Elsevier B.V. All rights reserved.

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