SPACE VECTOR PWM SIGNAL GENERATION FOR ANY MULTILEVEL INVERTER BY USING REVERSE MAPPING TECHNIQUE

This paper proposes a generalized method for the generation of space vector pulse width modulation (SVPWM) signals for multilevel inverters. In the proposed method, the actual sector containing the tip of the reference space vector need not be identified. A method is presented to identify the center of a sub hexagon containing the reference space vector. Using the center of the sub hexagon, the reference space vector is mapped to the innermost sub hexagon, and the switching sequence corresponding to a two-level inverter is determined. A new technique is proposed in this paper, by which these two-level vectors are translated to the switching vectors of the multilevel inverter by adding the center of the sub hexagon to the two-level vectors. The proposed method can be extended to any n-level inverter, and a generalized algorithm is proposed. The scheme is explained for a five-level inverter, and experimental results are presented for a three-level inverter and seven level Inverter

Numerical Simulations of Oscillating Soliton Stars: Excited States in Spherical Symmetry and Ground State Evolutions in 3D

Excited state soliton stars are studied numerically for the first time. The stability of spherically symmetric S-branch excited state oscillatons under radial perturbations is investigated using a 1D code. We find that these stars are inherently unstable either migrating to the ground state or collapsing to black holes. Higher excited state configurations are observed to cascade through intermediate excited states during their migration to the ground state. This is similar to excited state boson stars. Ground state oscillatons are then studied in full 3D numerical relativity. Finding the appropriate gauge condition for the dynamic oscillatons is much more challenging than in the case of boson stars. Different slicing conditions are explored, and a customized gauge condition that approximates polar slicing in spherical symmetry is implemented. Comparisons with 1D results and convergence tests are performed. The behavior of these stars under small axisymmetric perturbations is studied and gravitational waveforms are extracted. We find that the gravitational waves damp out on a short timescale, enabling us to obtain the complete waveform. This work is a starting point for the evolution of real scalar field systems with arbitrary symmetries.Comment: 12 pages, 11 figures, typos corrected, includes referee input, references corrected, published versio

Influence of Wave Parameters on Reshaping of Statically Stable Berm Breakwater in Shallow Water

Source: ICHE Conference Archive - https://mdi-de.baw.de/icheArchiv

Evolution of 3D Boson Stars with Waveform Extraction

Numerical results from a study of boson stars under nonspherical perturbations using a fully general relativistic 3D code are presented together with the analysis of emitted gravitational radiation. We have constructed a simulation code suitable for the study of scalar fields in space-times of general symmetry by bringing together components for addressing the initial value problem, the full evolution system and the detection and analysis of gravitational waves. Within a series of numerical simulations, we explicitly extract the Zerilli and Newman-Penrose scalar $\Psi_4$ gravitational waveforms when the stars are subjected to different types of perturbations. Boson star systems have rapidly decaying nonradial quasinormal modes and thus the complete gravitational waveform could be extracted for all configurations studied. The gravitational waves emitted from stable, critical, and unstable boson star configurations are analyzed and the numerically observed quasinormal mode frequencies are compared with known linear perturbation results. The superposition of the high frequency nonspherical modes on the lower frequency spherical modes was observed in the metric oscillations when perturbations with radial and nonradial components were applied. The collapse of unstable boson stars to black holes was simulated. The apparent horizons were observed to be slightly nonspherical when initially detected and became spherical as the system evolved. The application of nonradial perturbations proportional to spherical harmonics is observed not to affect the collapse time. An unstable star subjected to a large perturbation was observed to migrate to a stable configuration.Comment: 26 pages, 12 figure

Evaluation of Energy Consumption using Receiver–Centric MAC Protocol in Wireless Sensor Networks

At present day’s wireless sensor networks, obtain a lot consideration to researchers. Maximum number of sensor nodes are scattered that can communicate with all others. Reliable data communication and energy consumption are the mainly significant parameters that are required in wireless sensor networks. Many of MAC protocols have been planned to improve the efficiency more by enhancing the throughput and energy consumption. The majority of the presented medium access control protocols to only make available, reliable data delivery or energy efficiency does not offer together at the same time. In this research work the author proposes a novel approach based on Receiver Centric-MAC is implemented using NS2 simulator. Here, the author focuses on the following parametric measures like - energy consumption, reliability and bandwidth. RC-MAC provides high bandwidth without decreasing energy efficiency. The results show that 0.12% of less energy consumption, reliability improved by 20.86% and bandwidth increased by 27.32% of RC-MAC compared with MAC IEEE 802.11

Role of Host Proteins in HIV-1 Early Replication

After 33 years of the identification of HIV-1 infection, very little is known about the role of host cellular proteins. Till now considerable work has been done in the area of host- pathogen interactions facilitated by the viral proteins and host receptors. The role of the main receptor CD4 and co-receptors like CCR5, CXCR4 and their alternative receptors were well studied in disease progression. But the intracellular events during the host- pathogen interactions were poorly understood. Much data is available based on the global analysis of genome-wide RNA interference screens, yeast two-hybrid system and co-immunoprecipitation studies but their exact roles are not yet characterized. There are very few host proteins like APOBEC3G, LEDGF/p75, INI1, HMG I(Y), BAF which are well studied and characterized. Majority of the reported proteins are attributed to multiple functions. It will be useful to study such proteins to develop as future candidates in HIV-1 therapeutics