Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Stereoselective total synthesis of decarestrictine J

Abstract: Stereoselective total synthesis of decarestrictine J has been accomplished from inexpensive and commercially available starting materials. This concise synthesis utilizes Jacobsen’s hydrolytic kinetic resolution, regioselective ring opening of epoxide, and Yamaguchi macrolactonisation as key steps.

A Nonlinear Weight-Optimized Maintainability Index of Software Metrics by Grey Wolf Optimization

Abstract: Maintainability index (MI) is a software metric that offers measurements of the maintainability before release of the software by facilitating several substantial features of the system. In general, there is a common formula for determining the MI for all the software metrics to ensure the system's reliability. As it does not provide appropriate results regarding the reliability of the system, it is essential to focus on the next level of MI of software. Hence, this paper intends to allot an optimal weight and a constant to each software metric, which is optimized by grey wolf optimization (GWO). As a result, it can provide a new variant of MI by proposed enhanced model-GWO (EM-GWO). This optimized MI can ensure the efficiency of the respective software in such a way that it can provide an enhanced score from the system. Further, the proposed method is compared with conventional models such as enhanced model-generic algorithm (EM-GA), EM-particle swarm optimization (PSO), EM-ant bee colony (ABC), EM-differential evolution (DE), and EM-fire fly (FF), and the results are obtained.

Cluster Head Selection by Optimized Ability to Restrict Packet Drop in Wireless Sensor Networks

Abstract: Wireless sensor networks (WSNs) are comprised of spatially distributed autonomous nodes attached to the sensors to detect and maintain physical and environmental states. Energy efficiency is an important challenge in wireless sensor networks, in which the batteries are equipped with these sensors with limited amount of power and act as a power source, which having limited storage capacities. Thus, energy efficient routing techniques are required incorporate operations of wireless sensor networks to provide the network connectivity and routing of data with less energy consumption. Clustering in WSNs is greatest widespread mechanism in routing processes. Existing energy efficient clustering algorithms selects the cluster head based on energy status. However, these protocols cause the cluster head to become bottleneck and drops the packets due to insufficient buffer. Thus in this work, we propose a novel efficient metric to select the cluster head known as “optimized ability to restrict packet drop” to enhance the network lifetime. This metric provides the status of nodes with respect to energy and memory. Calculation of residual status of an intermediate node is done by knapsack algorithm. Performance of proposed work is analyzed by NS2, and the results show that our work outperforms in comparison with existing protocols.

Comparison of Saturated Hydraulic Conductivity Methods for Sandy Loam Soil with Different Land Uses

Abstract: Saturated hydraulic conductivity (Ks) is a quantitative measure of saturated soil properties and it is essential for designing irrigation, drainage and waste water systems, modelling studies for understanding and prediting rates of infiltration, runoff, erosion, seepage, upflux, solute transport and migration of pollutant to groundwater However, the accuracy of Ks is highly dependent on the method used, soil and surface characteristics The objective of the study was to compare Ks methods such as two in situ [Double ring infiltrometer (DRI), air entry permeameter (AEP)] and one pedotransfer function (PTF) based methods for four different land uses such as paddy field (PADF), mango field (MANF), cashew field (CASF) and playground (PLAG) The Ks obtained from the DRI, AEP and PTF methods were used to study the effect of the method and land use on Ks and suitability of a method for a land use It was observed that the measured Ks data using AEP and DRI of different land uses follow a log-normal distribution The mean Ks were significantly different for both measuring technique and the land use The AEP resulted highest (264 mm/h) and PTF lowest (159 mm/h) values of Ks, respectively for all land uses, whereas the Ks was highest (247 mm/h) and lowest (175 mm/h) for the land uses CASF and PLAG, respectively For all land uses, the mean Ks were highest for AEP followed by DRI, and PTF methods The order of Ks obtained for the land uses were CASF (251 mm/h), MANF (187 mm/h), PADF (182 mm/h) and PLAG (171 mm/h) Spatial variability of Ks was observed for DRI method and the land use PLAG The selection of best suitable method for a particular situation can be obtained by optimizing the interdependent parameters, including method to be used, accuracy in instrument and measurement methods, soil condition and the numbers of practical constraints of the investigation (eg, cost, availability of manpower, time requirement, portability of estimate, simplicity in measuring technique, operating condition)

Look Up Table Based Fuzzy Logic Controller for Unmanned Autonomous Underwater Vehicle

Abstract: The underwater vehicle is six degrees of freedom model. The execution of spatial maneuvers are determined mainly by the dynamic properties of underwater vehicle particularly controllability and stability. The control surfaces are situated at the rear end of the underwater vehicle which moves either vertically or horizontally (Pitch, Yaw, Roll, Pitch-rate,Yaw-rate etc.) used to steer the vehicle to run according to preprogrammed course as per logic till such a time the target is acquired. The underwater vehicle response is slow compared to air scenario due to constraints like higher density of water; the resistance motion is many hundred times greater than air. In this paper a rule-based fuzzy logic controller is designed for Yaw control, which is used for the rudder movement of an underwater vehicle. A Plant model is extracted using the input and output behavior and is assumed to be a linear time invariant second order. For on line implementation a decision table is stored in underwater vehicle computer memory in the form of Lookup table. For each combination of Inputs the required search will be done in the table and the appropriate value will be picked up. Using this technique the control algorithm becomes shorter and runs faster than those that reinterpret the rules at each control cycle of the system. This Lookup Table is used in the simulation of Yaw control of a Six Degrees of Freedom Model. The plant responses are compared for both conventional controller and fuzzy logic controller with regard to time of response, overshoot and steady state error.