Parallelization of computational models is key to utilizing the widely available computational resources of today to solve problems in ways the computational science community could not yesterday. The main focus of the work presented is in the parallelization of a Direct Numerical Simulation (DNS) nite-di erence Computational Fluid Dynamics (CFD) ow solver based on the Weighted Essentially Non-Oscillatory (WENO) scheme. The parallel DNS model was developed by modifying the existing serial model developed by Arshed Ghulam. An Alternating Direction Implicit (ADI) nite-di erence heat solver is also parallelized in an e ort to develop and re ne parallelization techniques. The Message Passing Interface (MPI) was utilized to manage the communication between processes. In addition to parallelization many improvements were made to the WENO model. The e ciency was increased by addressing memory locality and allocation. The con gurability of the model was increased by including multiple options adjustable within the model at runtime. A key-value con guration le reader was added to read in parameters from a le at runtime. The model was validated against the published serial version's results. The scalability was analyzed with respect to a set domain size and with respect to constant sub-domain size. For a given number of iterations the WENO model proves to scale perfectly with a constant sub-domain size. The results support that the same number of iterations can be performed on a domain of any size without time lost over that of a smaller domain, assuming the computational resources are available to keep the sub-domain per MPI process the same size as in the smaller analysis. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.

Various reports about greenhouse emissions over the past decade have raised the global consciousness regarding worldwide energy consumption in various arenas. The time has come to adopt energy-efficient methods in all areas, including computing devices. The need for energy efficiency in portable computing and communication devices is great, first due to the fact that because their usage has been increasing exponentially and, second, because little has been done in this field, with performance still being tracked as the focal point of development. One of the major features of any portable device is the wireless communication interface (typically a Wi-Fi card), with many applications being based on the Internet. A major concern with portable devices is maintaining a battery charge for long periods of time. All major applications like the voice over Internet protocol (VOIP), file transfer protocol (FTP), and video conferencing deplete a large amount of energy from portable devices. Thus, accounting for the energy consumption of the Wi-Fi card is very important, both to improve the battery lifetimes of these devices in the future and to reduce the amount of energy consumed from the power grid to charge these batteries. In this thesis, the energy consumption of the Wi-Fi interface in portable devices, such as laptops and smartphones, was calculated for various applications. Energy consumption was measured experimentally and then scaled to account for the large number of devices in use. The carbon footprint was calculated and the offset required was determined. Considering the explosive growth in the number of portable devices in use, projections on energy consumption over the next few years were made. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

The use of nanotechnology is rapidly growing in various fields for different applications such as aerospace, electronics, construction, biomedicine, cosmetics etc. Nanomaterials posses unique size dependent material properties and can manipulate the host material properties to a greater extent compared to the micron sized particles of the same composition, and make them suit the requirements. Various kinds of nanomaterials with different size and shapes such as particulate, fibrous, layered, tube and foam when added to the host matrix material in composites will tailor the properties of the matrix material to a greater extent making nanocomposites a good alternative to conventional composites. In this research, more emphasis is made on improving mechanical and other physical properties of recycled high-density polyethylene (HDPE) polymer by adding graphene nanoplatelets at different concentrations. Recycled HDPE graphene nanocomposites were prepared using a solvent method assisted by a sonication method where samples are processed in to dog bone shaped specimens by using an injection molding process. For comparision, samples of plain recycled HDPE without graphene nanoplatelets were prepared. The samples were tested to evaluate the improvement in physical properties as function of the graphene concentrations in the polymer matrix. Physical properties of these samples were determined using different techniques: a) thermal conductivity which is found by using axial flow comparative cut bar method, b) dielectric constant is found by measuring capacitance of parallel plate capacitor setup using a capacitance bridge, c) water contact angle is found by optical angle goniometer, and d) tensile modulus is found by uniaxial tensile testing. The morphological characterization of PMN samples is performed using SEM technique to observe the type of distribution and dispersion of graphene nanoplatelets in the polymer matrix. The test results showed that adding graphene into recycled matrix drastically changed the physical properties of the materials. This may improve the value of the recycled materials for various applications. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

In a manufacturing environment, productivity and quality of the system can be improved by focusing on production constraints (bottlenecks). As a result, the bottleneck detection methods have gained more importance in enhancing the performance of the system. There are several short-term and long-term bottleneck detection methods. This research focuses on inactive state duration bottleneck detection for multiple product flow as high complexity arises in material flow due to several products and different processing sequences. The efficiency of the proposed methodology is validated by case studies using discrete event simulation models. The integration of simulation tool to detect bottlenecks in the manufacturing system has been useful in real-time case studies. An automatic bottleneck detection method was proposed to identify the bottleneck time and bottleneck machines in an easier manner. Previous research focuses on additional capacity and buffers to machines to mitigate the bottleneck. This approach spotlights the selection of alternative process plan in the presence of bottlenecks with a objective of minimized bottleneck time and minimized machining cost of the products in the given process plan. A mathematical model was presented with these objectives. Case studies were conducted for initially selected process plan and alternative process plan to show the improvements in system performance. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Industrial and Manufacturing Engineering.

The loss of properties due to the ultra violet (UV) light exposure has been a long standing problem in composite materials. To overcome this issue, the composite materials are often coated with a polymeric material. Even though the polymers offer improved resistance against UV degradation, they are not a comprehensive solution to overcome the problem, because over a prolonged period of time, the coatings themselves are susceptible to UV degradation. This research was aimed to improve the resistance of the coatings against the UV degradation. In order to achieve that, nanoscale additive, namely graphene, was uniformly dispersed into the coatings, and then applied onto the surface of the glass fiber reinforced composite materials. It was hypothesized that graphene, being a very good nano reinforcement material, would act as a strong binding agent and increase the resistance of the coating against the UV degradation. The effects of the addition of the nano-additives were tested by performing atomic force microscopy, water contact angle measurement, coating thickness measurement and the FTIR studies. The experimental results confirmed that addition of nano-additives does in fact improve the resistance of the coatings against UV degradation. As a result, this study will prove a number of advantages for different industrial applications. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Mechanical Engineering.

On demand ad hoc routing protocols such as AODV and DSR do not look for new routes unless there is a change in the network topology. In scenarios where same intermediate node is used for longer time, this behavior may cause the traffic concentration on few intermediate nodes resulting in large latency and depletion of battery power at the nodes. To overcome this problem, a load balancing algorithm is proposed in this thesis. Each node forwards its residual energy information to all its neighbor nodes using reserved fields in the hello packets. Each node calculates a desirability metric, for each of its neighbor, based on the neighbor‟s energy information and the available bandwidth towards it. The choice of a particular route depends upon the desirability metric of the next hop. The proposed scheme is independent of the underlying routing protocol however the routing protocol should be able to save multiple routes to a destination and be able to put and retrieve the energy information to and from the hello messages. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

Today, there is an exponential growth in the use of laptops for computing and communication. However, the battery life of laptops is only a few hours, at best. Furthermore, studies indicate that laptops contribute to approximately 1% of the overall global energy consumption. Thus, there are significant incentives to minimize the energy consumed by laptops. To achieve this goal, it is important to understand the energy expended by each component of a laptop. Initially in this work, the power consumed by each component of a modern laptop was systematically studied. Results indicate that wireless communication has been a significant consumer of power, particularly obvious power hogs being the display, graphics card, and processor. A subsequent study of energy consumption of portable devices using a remote cloud application compared to local execution revealed some interesting facts. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

The thesis investigates a pair of stationary stochastic process models whose domains are the set of integers and the set of real numbers respectively. The stationary processes with our specific correlation functions include the discrete and continuous first and second order autoregressive processes as their special cases. The maximum likelihood method is then applied to obtain the nonlinear equation system for the maximum likelihood estimators of the model parameters and the solutions are found by using the deepest gradient algorithm. The advantage of the algorithm lies in the calculation could be divided into several steps at a cost of O(n) calculations per step. Finally, predictions are given for both simulated data and Wichita temperature data. / Thesis (M.S.)--Wichita State University, College of Liberal Arts and Sciences, Dept. of Mathematics and Statistics / This research is supported in part by the Kansas NSF EPSCoR under Grant EPS 0903806 and in part by a Kansas Technology Enterprize Corporation grant on Understanding Climate Change in the Great Plains: Source, Impact, and Mitigation.

Linear increase-decrease algorithms have applicability in various fields of research. For instance, transmission control protocol (TCP) congestion control mechanism employs an additive increase and multiplicative decrease (AIMD) algorithm to vary the congestion window size dynamically at the sender. Recently, an adaptive algorithm for sensor activation in renewable energy based systems was proposed. This activation algorithm is designed in such a way that the sensor dynamically computes its sleep interval according to additive increase and multiplicative decrease, based on its current energy level. The objective is to maximize the asymptotic event detection probability achieved in the system in the presence of uncertainties and energy constraints. This thesis provides a simple, but accurate model to compute the performance of the algorithm for a single sensor scenario. By means of the proposed model, the performance of the algorithm is evaluated and is validated with that of the results obtained from simulations. A Markov Chain is used to analyze the system for a single sensor scenario. Furthermore, the AIMD based algorithm is extended towards a distributed implementation in a network with multiple sensors and multiple event processes. Through extensive simulations, it is shown that the proposed algorithm performs better than other algorithms in this scenario. In addition, the proposed algorithm is completely localized, which makes it extremely suitable for distributed deployment. / Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science Engineering.

In the past thirty years childhood obesity rates have doubled and even tripled in some age groups in the U.S. (Centers for Disease Control and Prevention, 2008). It has become so severe and affected so many children, it has recently been labeled an epidemic by the World Health Organization (2009). Reports demonstrate that rates are higher among co-cultural populations such as African Americans and Hispanics and vary across populations between females and males (CDC, 2008). One strategy employed by many organizations to help reduce the rate of childhood obesity is the use of mass media campaigns (Evans, 2008). Due to the rise in childhood obesity rates and the use of mass media campaigns in an effort to reduce those rates, this study examines childhood obesity media campaigns and their impact on the populations they target. Because rates are higher among co-cultural populations and because they also differ between female and male children, this study examines how campaigns use various techniques to convey health messages to children of specific populations and of different sex. In order to determine if the strategies the campaigns employ are different among the diverse racial and ethnical populations and between female and male children and to determine the specific strategies utilized, articles that report on the effectiveness of campaigns will be systematically reviewed. Employing Glaser & Straus’ (1967) constant comparative analysis methodology, this study will utilize prior research to identify codes and report on strategies that appear throughout campaign literature (Glaser & Straus, 1967). Using a systematic approach, articles that report on (1) the effectiveness of childhood obesity media campaigns (2) childhood obesity campaigns targeting racial and ethnical populations and (3) campaigns with female and male children will be identified and selected for the study. Articles will then be read and coded and the results reported. / Thesis (M.A.)--Wichita State University, College of Liberal Arts and Sciences, the Elliott School of Communication.