Digital Commons Network^™

Efficient Reinforcement Learning In Multiple-Agent Systems And Its Application In Cognitive Radio Networks, Jing Zhang

Dissertations

The objective of reinforcement learning in multiple-agent systems is to find an efficient learning method for the agents to behave optimally. Finding Nash equilibrium has become the common learning target for the optimality. However, finding Nash equilibrium is a PPAD (Polynomial Parity Arguments on Directed graphs)-complete problem. The conventional methods can find Nash equilibrium for some special types of Markov games.

This dissertation proposes a new reinforcement learning algorithm to improve the search efficiency and effectiveness for multiple-agent systems. This algorithm is based on the definition of Nash equilibrium and utilizes the greedy and rational features of the agents. When …

Adaptive Radial Basis Function Neural Networks-Based Real Time Harmonics Estimation And Pwm Control For Active Power Filters, Eyad Kh Almaita

Dissertations

With the proliferation of nonlinear loads in the power system, harmonic pollution becomes a serious problem that affects the power quality in both transmission and distribution systems. Active power filters (APF) have been proven to be one of the most successful methods for mitigating harmonics problems. So far, different techniques have been used in harmonics extraction and control of APF to satisfy the fast response and the accuracy required by the APF. Neural networks techniques have been used successfully in different real-time and complex situations. This dissertation demonstrates four main tasks; (i) a novel adaptive radial basis function neural networks …

Optical And Electrochemical Properties Of Monolayer Protected Gold Clusters Modified With Fluorophores, Mary Sajini Devadas

Dissertations

My research focused on the synthesis, characterization and the investigation of the optical and electrochemical properties of monolayer-protected quantum-sized gold clusters. Significant research attention was focused on the solution phase optical and electrochemical properties of these clusters. Highly monodisperse Au clusters with different types of ligands were successfully synthesized with sizes varying from 1 nm to 13 nm. These preformed gold clusters were modified with fluorophores and pseudo-rotaxanes for developing better nonlinear optical materials for sensing and biological imaging purposes. We have tried to focus on the interaction of the outer ligand shell, made up of –S-Au-S-Au-S- bonds, with the …

The Variation Of Hydrogen Concentration In Ni/Mgh Thin Film With Temperature, Rex Nyadaufe Taibu

Masters Theses

The thermal stability of Ni/MgH thin film deposited on Si substrate by Unbalanced Magnetron Physical Vapor Deposition has been investigated using Ion Beam analysis (DBA) techniques. Rutherford Backscattering Spectrometry (RBS) and Non-Rutherford Backscattering Spectrometry (NRBS) have been used to find the composition of Magnesium, Nickel and Oxygen. Elastic Recoil Detection Analysis (ERDA) has been used to determine the concentration of hydrogen at each level of heating. Heating was done in the Ultra High Vacuum (UHV) environment using a non gassy button heater. Ni/MgH sample had lost most of its hydrogen after being heated to a temperature of about 125°C in …