Vignans Institute of Information Technology

Vishakhapatnam, India

Vignans Institute of Information Technology

Vishakhapatnam, India
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Ravi Sankar R.S.,Vignans Institute of Information Technology | Jaya Kumar S.V.,Vignans Institute of Information Technology | Deepika K.K.,Vignans Institute of Information Technology
Indonesian Journal of Electrical Engineering and Computer Science | Year: 2016

This paper deals with the design and simulation of an efficient solar photovoltaic system with a maximum power point tracking system (MPPT). Maximum power point (MPP) is obtained by using Perturb and Observe (P&O) algorithm. The output from solar panel is fed to the DC-DC (Boost) converter which steps up the output voltage. It is then fed to a 3-phase inverter. The inverter used is a 3-phase two-level inverter implemented with a Model Predictive Control strategy. Model of the system is considered in order to predict the control variables. Optimum switching state is selected by minimizing the cost function for each sampling period. This is achieved through modelling and MATLAB simulation of various stages that constitute the overall system. © 2016 Institute of Advanced Engineering and Science. All rights reserved.

Mishra A.,Vignans Institute of Engineering for Women | Kumar G.V.N.,Vignans Institute of Information Technology
International Journal of Power and Energy Conversion | Year: 2017

Due to massive increase in the power transactions due to restructuring, the stress in transmission lines has increased largely and severity assessment is very essential. Contingency assessment of a power system predicts the effect of outages in transmission lines and generator units. In this paper, contingency ranking of the lines has been done using composite severity index. A risk-based strategy has been adopted for the placement of interline power flow converter (IPFC). From the list of the severe lines obtained, IPFC is placed on the line which has highest possibility of severity during the occurrence for different outages. To verify the proposed methodology, it is implemented on IEEE 30 and Indian Utility 62 bus systems. The load on the bus with highest load is further increased gradually up to the critical value and the results have been presented and analysed to ascertain the effectiveness of IPFC for contingency management. © 2017 Inderscience Enterprises Ltd.

Mishra A.,Vignans Institute Of Engineering For Women | Nagesh Kumar G.V.,Vignans Institute of Information Technology
Journal of Engineering Science and Technology | Year: 2017

In today’s electronic world, secured operation of the electric power system is one of the foremost requirements. Contingency analysis and management thus becomes the basic requirement of system analysis. In this paper, the contingency study has been done on a heavily loaded practical power system in an Indian scenario. A Composite Severity Index (CSI) has been proposed for the determination of critical line. The contingency analysis has been done using Rapid Contingency Ranking Technique (RCRT). By this method the number of lines on which the contingency analysis is to be performed is greatly reduced. Thereafter, an Interline Power Flow Controller (IPFC) has been placed in the system on the basis of CSI for improvement of the system situation post-contingency. An IPFC has been found to be very effective in the improvement of system condition of the heavily loaded Indian system. © School of Engineering, Taylor’s University.

Swamy Naidu N.V.,Gandhi Institute of Technology and Management | Sateesh B.,Vignans Institute of Information Technology
International Journal of Computational Methods | Year: 2015

The development of a new four node 24 degree of freedom bilinear degenerated shell element is presented for the analysis of shell structures. The present finite element formulation considers the assumed covariant transverse shear strains to avoid the shear locking problem and the assumed covariant membrane strains, which are separated from covariant in-plane strains, to overcome the membrane locking problem. The formulation also includes the deviation of the normal torsional rotation of the mid surface in the governing equation. This element is free from serious shear and membrane locking problems and undesirable spurious kinematic deformation modes. The element is tested for rigid body modes and distorted edges to meet the patch test requirements. The versatility and accuracy of this new degenerated shell element is demonstrated by solving several numerical examples for thick and thin plates. © 2015 World Scientific Publishing Company.

Premamayudu B.,Andhra University | Rao K.V.,Vignans Institute of Information Technology | Varma P.S.,Adikavi Nannaya University
Advances in Intelligent Systems and Computing | Year: 2014

Key Management is an important challenging issue in wireless sensor networks to provide the confidentiality for the sensitive data which is sensed by the sensors from various fields. There are so many resource constraints for wireless sensor networks, implementing key management scheme in WSN. In general many key management schemes are proposed for Computer Networks like ECC, Diffie-Hellman, RSA and public key based schemes, but all are not suitable for wireless sensor networks. WSNS are suitable for many applications like Smart homes, Automation, Vehicular traffic management, Habitat Monitoring, Precision agriculture, Disaster detection and Surveillance. All the applications need secure communication and must protect from the eavesdropping, key compromising, sensor node capture attack, and message authentication. In this paper, we propose A Novel Pairwise Key Establishment and Management in Hierarchical Wireless Sensor Networks (HWSN) Using Matrix to prevent all the above attack and to achieve network connectivity, scalability, and resilience for the network. This scheme is used for the heterogeneous sensor networks. In this scheme, Base station prepares the key matrices for Cluster heads and Sensor nodes and generates the key chains for both cluster head and sensor nodes and preloaded before deployment. Our scheme prevents the following attacks: sensor capture attacks, key compromising attacks, malicious node attacks.

Sandeep G.,Vignans Institute of Information Technology | Nagasree K.P.,Andhra University | Hanisha M.,Andhra University | Kumar M.M.K.,Andhra University
BMC Research Notes | Year: 2011

Background: AUTODOCK Vina is an open-source program which is steadfast and authentic to perform docking simulations. Though, Auto Dock Tools can help perform docking simulations with Vina, it largely remains as a platform for docking single molecule at a time. Findings. "AUDocker LE" is designed with an aim to develop a software tool as a front end graphical interface with C# language to perform docking experiments in Windows based computers. It helps users to perform automated continuous docking of large ligand databases into a set of predefined protein targets. It will also help the user to analyze the results to select promising lead molecules. Conclusion: AUDocker LE provides a straight forward graphical interface which can be used in a standard personal computer with Microsoft Windows XP or Windows 7 as the operating system where Autodock Vina, Python 2.5 frame work are preinstalled. © 2011 Sandeep et al.

Sateesh B.,Vignans Institute of Information Technology | Maiti D.K.,Indian Institute of Technology Kharagpur
Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering | Year: 2010

The effects of runway unevenness on the design and operation of an aircraft have been subjected to investigations for a number of years. Runway roughness will, in general, produce both longitudinal and lateral excitations. This article examines the lateral stability of linear and non-linear models of an aircraft nose landing gear (NLG) subjected to ground-induced lateral excitation. Simulations of ground profile and ground excitation modelling have been performed and numerical studies were carried out to bring out the effect of runway roughness and its interaction with torsional free play. The results show that a small amount of runway excitation causes a significant reduction in the critical shimmy velocity and, in combination with free play, it has an adverse impact on lateral stability of the NLG of an aircraft. Finally, a study has been performed to postpone the dynamic instability by introducing a magnetorheological (MR) fluid-based damper and enhanced torque arm stiffness.

Chowdary D.D.,Vignans Institute of Engineering for Women | Kumar G.V.N.,Vignans Institute of Information Technology
Indian Journal of Engineering and Materials Sciences | Year: 2010

Voltage sags defined as short-duration reductions in the rms voltage on one or more electrical phases are becoming the most important power quality concern to electric utility customers with sensitive loads. They are characterized by their magnitude and duration (which is typically 0.5 to 30 cycles). Sags are predominantly caused by faults that are unavoidable on the distribution systems due to the interconnectivity of the utility systems. The distribution-class dynamic voltage restorer (DVR) is a series connected power electronics device which can compensate for distribution system sags and swells. By enhancing the voltage, the DVR can increase the availability of sensitive loads. For a successful compensation, the DVR must be able to detect the voltage sag and control the inverter to restore the voltage. The sliding mode control is used for the DVR. Using sliding mode control to the DVR, additional sag detection method is eliminated. This improves the dynamic response of the DVR and also DVR is able to compensate for any variation in source voltage. In this paper, a DVR with sliding mode control strategy is used to alleviate the voltage sags caused due to faults occurring on the parallel feeders in a single-phase distribution system. The DVR along with the other parts of the distribution system are simulated using MATLAB/SIMULINK.

Hanumantharao R.,Vignans Institute of Information Technology | Kalainathan S.,Vellore Institute of Technology
Bulletin of Materials Science | Year: 2013

Vickers and Knoop microhardness tests were carried out on grown L-alanine single crystals by slow evaporation technique over a load range of 10-50 g on selected broad (2 0 3) plane. Vickers (Hv) and Knoop (Hk) microhardness for the above loads were found to be in the range of 60-71 kg/mm2 and 35-47 kg/mm2, respectively. Vickers microhardness number (Hv) and Knoop microhardness number (H k) were found to increase with increasing load. Meyer's index number (n) calculated from Hv shows that the material belongs to the soft material category. Using Wooster's empirical relation, the elastic stiffness constant (c11) was calculated from Vickers hardness values. Young's modulus was calculated using Knoop hardness values. Hardness anisotropy has been observed in accordance with the orientation of the crystal. © Indian Academy of Sciences.

Hanumantharao R.,Vignans Institute of Information Technology | Kalainathan S.,Vellore Institute of Technology
Journal of Thermal Analysis and Calorimetry | Year: 2013

A new nonlinear optical crystal urea thiourea cadmium sulfate (UTCS) has been grown by slow evaporation technique in equimolar ratio. The grown crystals were characterized by single crystal X-ray diffraction analysis which reveals that sample crystallizes in triclinic system with non-centrosymmetric space group P1. The powder XRD pattern revealed the formation of UTCS compound. High-resolution-X-ray diffraction analysis was carried out to study the crystalline perfection of the sample. Functional groups of the grown crystal were identified by FT-IR studies. Thermo gravimetric and differential thermal analyses were employed to understand the thermal and physio-chemical stability of the synthesized compound. UV-Vis-NIR spectrum revealed the transmission properties of the crystal specimen. The SHG efficiency has been tested by the Kurtz powder technique using Nd: YAG laser and found to be about 0.82 times in comparison with standard KDP crystals. © 2013 Akadémiai Kiadó, Budapest, Hungary.

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