Evaluation of Best Satellite-Receiver Geometry for Improved IRNSS/GPS Position Accuracy

A GPS-IRNSS combined navigation system is emerging in India. It is possible to increase the accuracy of the receiver or user's position at any time and under any weather conditions with a combined system. It is possible to use these navigation systems for finding the precise location of receivers in civil aviation, precision applications such as surveying, disaster management, and other applications. Usually, satellite navigation systems are based on a geometric relationship between satellite and receiver, with errors caused by atmospheric conditions, multipath, and other factors affecting accuracy. Geometry of satellite receivers is measured by the Dilution of Precision (DOP), a unit less quantity. This paper investigates the possibility possible to obtain better accuracy by combining GPS and IRNSS constellations. This improved accuracy is typically useful for precision applications such as surveying and disaster management

QoS Constrained Optimal Sink and Relay Placement in Planned Wireless Sensor Networks

We are given a set of sensors at given locations, a set of potential locations for placing base stations (BSs, or sinks), and another set of potential locations for placing wireless relay nodes. There is a cost for placing a BS and a cost for placing a relay. The problem we consider is to select a set of BS locations, a set of relay locations, and an association of sensor nodes with the selected BS locations, so that number of hops in the path from each sensor to its BS is bounded by hmax, and among all such feasible networks, the cost of the selected network is the minimum. The hop count bound suffices to ensure a certain probability of the data being delivered to the BS within a given maximum delay under a light traffic model. We observe that the problem is NP-Hard, and is hard to even approximate within a constant factor. For this problem, we propose a polynomial time approximation algorithm (SmartSelect) based on a relay placement algorithm proposed in our earlier work, along with a modification of the greedy algorithm for weighted set cover. We have analyzed the worst case approximation guarantee for this algorithm. We have also proposed a polynomial time heuristic to improve upon the solution provided by SmartSelect. Our numerical results demonstrate that the algorithms provide good quality solutions using very little computation time in various randomly generated network scenarios

Comparison between experimental and analytical behaviour of the steel – concrete composite pushout specimen with stud and channel shear connector

To investigate the behaviour of composite action with various shear connectors, push-out tests were performed for eight specimens. Test parameters includes are type of shear connector (headed stud connector and channel connector), number of connectors (one and two) and specimen with or without decking sheet. Test results showed that performance of the push-out specimens depends greatly on type of connector and decking sheet. From the experimental study it was observed that the performance and shear capacity of channel connector was 60 % more than the stud connector. The shear resistance between the steel and concrete was enhanced up to 50 % for the push out specimen without decking. The specimen with two numbers of stud and channel connector increases the strength by 58% and 23% respectively as compared to specimen with single connector. The behaviour of the push out specimen was stimulated by three-dimensional finite element model using software ANSYS workbench. The analytical behaviour was well agreement with the real push out specimen studied experimentally

Comparison between experimental and analytical behaviour of the steel – concrete composite pushout specimen with stud and channel shear connector

To investigate the behaviour of composite action with various shear connectors, push-out tests were performed for eight specimens. Test parameters includes are type of shear connector (headed stud connector and channel connector), number of connectors (one and two) and specimen with or without decking sheet. Test results showed that performance of the push-out specimens depends greatly on type of connector and decking sheet. From the experimental study it was observed that the performance and shear capacity of channel connector was 60 % more than the stud connector. The shear resistance between the steel and concrete was enhanced up to 50 % for the push out specimen without decking. The specimen with two numbers of stud and channel connector increases the strength by 58% and 23% respectively as compared to specimen with single connector. The behaviour of the push out specimen was stimulated by three-dimensional finite element model using software ANSYS workbench. The analytical behaviour was well agreement with the real push out specimen studied experimentally