Engineering Commons^™

New Covariance-Based Feature Extraction Methods For Classification And Prediction Of High-Dimensional Data, Mopelola Adediwura Sofolahan

Open Access Dissertations

When analyzing high dimensional data sets, it is often necessary to implement feature extraction methods in order to capture relevant discriminating information useful for the purposes of classification and prediction. The relevant information can typically be represented in lower-dimensional feature spaces, and a widely used approach for this is the principal component analysis (PCA) method. PCA efficiently compresses information into lower dimensions; however, studies indicate that it is not optimal for feature extraction especially when dealing with classification problems. Furthermore, for high-dimensional data having limited observations, as is typically the case with remote sensing data and nonstationary data such as …

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …

Analysis And Optimization Of Cooperative Wireless Networks, Phuong Thanh Tran

Open Access Dissertations

Recently, cooperative communication between users in wireless networks has attracted a considerable amount of attention. A significant amount of research has been conducted to optimize the performance of different cooperative communication schemes, subject to some resource constraints such as power, bandwidth, and time. However, in previous research, each optimization problem has been investigated separately, and the optimal solution for one problem is usually not optimal for the other problems.

This dissertation focuses on joint optimization or cross-layer optimization in wireless cooperative networks. One important obstacle is the non-convexity of the joint optimization problem, which makes the problem difficult to solve …

Information Measures For Statistical Orbit Determination, Alinda Kenyana Mashiku

Open Access Dissertations

The current Situational Space Awareness (SSA) is faced with a huge task of tracking the increasing number of space objects. The tracking of space objects requires frequent and accurate monitoring for orbit maintenance and collision avoidance using methods for statistical orbit determination. Statistical orbit determination enables us to obtain estimates of the state and the statistical information of its region of uncertainty given by the probability density function (PDF). As even collision events with very low probability are important, accurate prediction of collisions require the representation of the full PDF of the random orbit state. Through representing the full PDF …