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The Sarbanes-Oxley (SOX) Act of July 2002 was created to address the financial malfeasance revealed during the investigations of several large firms by the Securities and Exchange Commission (SEC). The Act required public companies traded on U.S. exchanges to provide increased transparency in financial statements. Key portions of the legislation required firms to create internal financial controls and placed personal accountability with top executives. SOX mandated and standardized a greater degree of self-regulation. In the years following SOX, firms experienced significantly higher compliance costs, but they also benefited from the reduction of statement errors and fraud, increased accuracy in reporting, and greater investor confidence. After the Sarbanes-Oxley (SOX) Act of 2002, anecdotal evidence suggested that SOX impeded small, research intensive firms. We looked at research intensive firms going public before and after SOX to determine if there was a change in volume and quality of research intensive firms post-SOX. We found that firms that went public after SOX were fewer and had lower patenting activity. In the case of small and medium size firms, the cost of SOX compliance is likely to divert funds from research investments. We speculate that highly research intensive firms are more likely post-SOX to divert their IPO to non-U.S. exchanges, delay going public, or dismiss the idea of going public, as proposed in a “3Ds” model. The 2002 SOX US Congressional Act levied millions of dollars in new compliance costs on each foreign or domestic firm that went public on U.S. exchanges. Funding for regulatory expenditures must come from somewhere. We proposed that one likely candidate was research budgets, as research efforts have a more distant, less immediately visible, long term effect on firm performance. We suggested that large firms more easily absorbed the additional costs of SOX with a reduced effect on research and development budgets, while small firms were less able to maintain research budgets after SOX. In the aftermath of SOX, research spending did go down, most visibly in Biotech and Electronics. As the total number of IPO firms decreased dramatically after SOX, these two research intensive industries, plus Computer Software, were the only industries with a large enough sample size to evaluate. We saw that research intensive firms diminished dramatically, along with many non-research intensive firms, from IPO events after SOX. Where we had sufficient sample size, in computer software, biotechnology, electronics, and “other”, we noted that research-intensive firms generally resisted the temptation to raid research budgets, finding funding for compliance elsewhere within the company or from the additional cash flow at time of IPO. Where firms did appear to greatly reduce research budgets was in the non-research intensive industries, where research budgets might be more of a discretionary expense. Firm size was not a factor in whether research intensive firms could better absorb the costs of SOX, although smaller firms tended to spend proportionally more on research in an effort to grow faster. After the enactment of SOX, we observed an indication that the markets valued research intensity even more than prior to SOX, perhaps understanding the vulnerability of research budgets being diverted to compliance costs. Overall, the data suggested that the effect of SOX was underestimated in this study, as the firms that were deterred from going public on U.S. exchanges were not in the sample evaluated. We only analyzed those firms prepared to accept the higher costs of SOX. The data set consisted of survivors, selected firms still willing to pay for SOX compliance as well as for research programs. / Business Administration/Strategic Management

Solid rocket motors consist of a thin metallic or composite shell filled with a soft rubbery propellant. Such motors are vulnerable and prone to buckling due to sudden external pressures produced by nearby detonation. The stability conditions of rocket motors subjected toaxisymmetric, external pressure loading are examined. The outer cases of motors are considered as isotropic (metallic) or anisotropic (composite), thin and high-strength shells, which are the main structures of interest in the stability analyses. The inner, low-strength elastic cores are modeled as linear and nonlinear elastic foundations. A general, refined, Sanders' nonlinear shell theory, which accounts for geometric nonlinearity in the form of von Karman type of nonlinear strain-displacement relations, is used to model thin-walled, laminated,composite cylindrical shells. The first order shear deformable concept is adopted in the analyses to include the transverse shear flexibility of composites. A winkler-type of linear and nonlinear elastic foundation is applied to model the internal foundations. Pasternak-foundation constants are also chosen tomodify the proposed elastic foundation model for the purpose of shear interactions. A set of displacement-based finite element codes have been formulated to determine critical buckling loads and mode shapes. The effect of initial imperfections on the structural responses are also incorporated in the formulations. A variety of numerical examples are investigated to demonstrate the validity and efficiency of the purposed theory under various boundary condiitions and loading cases. First, linear eigenvalue analysis is used to examine approximate buckling loads and buckling modes as well as symmetric conditions. An iterative solution procedure, either Newton-Raphson or Riks-Wempner method is employed to trace the nonlinear equilibrium paths for the cases of stress, buckling and post-buckling analyses. Both ring and shell-type models are applied for the structural analyses with different internal elastic foundations and initial imperfections. / Ph. D.

This thesis deals with the control of a highly maneuverable miniature helicopter about trajectories, generated online, from a library of prespecified maneuvers. Linearizing the nonlinear equations describing the helicopter dynamics about the prespecified, library maneuvers results in a hybrid linear time-varying (LTV) model. Two control approaches are used to design controllers corresponding to each library maneuver: the standard L2-induced norm approach and an approach which also uses the L2-induced norm as a performance measure while accounting for uncertain initial states. Each control approach is evaluated in closed-loop simulation with a nonlinear helicopter model. The controllers are set to drive the helicopter model to track desired trajectories in the presence of disturbances such as wind gusts, turbulence, sensor noise, and uncertain initial conditions. For the specific plant formulations and trajectories presented, performance is comparable for both control approaches; however, it is possible to improve controller performance by exploiting some of the features of the approach accounting for uncertain initial states. These improvements in performance are topics for future work along with implementation of the presented approaches and results on a remote control helicopter. / Master of Science

Hydrocyclone density-driven particle separation may offer up improved settling performance for wastewater treatment facilities experiencing poor settleability. Hydrocyclones are fed mixed liquor through the feed inlet and experience a centrifugal motion that separates solids based on density. The variation in hydrocyclone nozzle sizes will report different calculated hydraulic and mass split percentages for the overflow and underflow. Previous research conducted with hydrocyclones have at multiple full-scale facilities used a 10 m3/hr hydrocyclone to promote better settleability as well as aid the formation of aerobic granular sludge (AGS). There has been a multitude of settling improvement experiments and initiatives for full scale wastewater treatment. However, little research has been produced utilizing larger hydrocyclones (20 m3/hr) at a full-scale wastewater treatment facility during continuous operation. Two Hampton Roads Sanitation District (HRSD) plants served as sites for this research: James River (JR) Wastewater Treatment Plant located in Newport News, VA and Urbanna (UB) Wastewater Treatment Plant located in Urbanna, VA. Both treatment facilities have utilized the hydrocyclone for more than two years, to fulfill wasting requirements. The JR plant operates the hydrocyclone continuously for wasting purposes, while UB only uses the hydrocyclone for approximately 30-45 minutes per day. In order to evaluate the effectiveness of the hydrocyclone and its overall impact on settleability at the JR plant, eight hydrocyclones were installed. JR samples were taken from the underflow sample port (representing a mixture of underflow samples representing the number of hydrocyclones operational at the sample time) and overflow samples were taken from the outfall point of a single hydrocyclone. The UB plant only operated one 5 m3/hr hydrocyclone on Treatment Train 1 during wasting operations, while Treatment Train 2 served as the control train for the duration of this research. Hydrocyclone performance at JR was assessed through direct measurement of hydraulic and mass split of the underflow and overflow components, initial settling velocity (ISV), sludge volume index (SVI), and SVI5/SVI30 ratio. UB hydrocyclone and settling performance was measured by ISV, SVI5, SVI30, and SVI5/SVI30 ratios during different comparison experiments: hydrocyclone vs. no hydrocyclone, hydrocyclone vs. polymer addition, and hydrocyclone with polymer addition to Train 1 vs. polymer-only addition to Train 2. Nutrient concentrations from both treatment trains were collected and analyzed to determine any significant changes based on hydrocyclone use. T-test statistical analysis, and a dose response analysis included direct measurements of the ISV, SVI5, SVI30, mass split percentages, along with the effect of polymer with and without the use of a mechanical selector. Hydrocyclone settleability measurements at JR over time revealed a statistically significant positive correlation with the ISV, SVI5, and SVI30 measurements of the aeration effluent. Therefore, the hydrocyclone statistically had a strong impact on three settling parameters that are instrumental in determining overall settling efficiency. Statistically, no strong correlation was determined between the hydrocyclone operation and the total phosphorus (TP) concentration in the secondary effluent, or the ferric addition to the secondary clarifiers. The dose response based on the underflow ISV rate provided understanding of the nozzle comparison and the effect it provided to the underflow sample. Hydrocyclone performance at UB was hindered by the re-seed of Train 1 (inDENSE™) due to over wasting, and most of the data were not representative. Before the re-seed, hydrocyclone performance was improving the overall settleability of the mixed liquor in comparison to Train 2 (Control). All settling parameters measured were in favor of the hydrocyclone operation. After the re-seed the plant mixed liquor changed microbial populations for a brief time and was not representative of the overall treatment efficacy. The hydrocyclone did provide a quicker settling velocity than the polymer addition when the polymer addition was steady, and through both polymeric spikes. Polymeric addition to both trains, while inDENSE™ train still employing the hydrocyclone did not provide any conclusive data as to whether polymer addition with the use of a hydrocyclone was more effective than polymer-only addition. Nutrient profiles from UB did not provide any change in NH4-N, NO3-N, NO2-N, or PO4-P, with the hydrocyclone being operational or not on the secondary clarifier effluent. / Master of Science / Wastewater treatment facilities rely on settling tests to be indicators for plant settling performance. A way to improve plant settling is to separate the sludge on a density basis and retain the dense sludge in the system for better performance downstream, while the less dense sludge is taken out of the system. By implementing a mechanical device that can ensure the separation of dense material and be retained in the system can aide in improved plant settling performance by improving settling parameter measurements. With the ability of using a mechanical device (a hydrocyclone) to physically separate sludge on a density-basis, it will improve settling measurements of the plants taken by operators on a daily basis.

Millimeter wave systems leverage beamforming to generate narrow, high-powered beams for overcoming the increased path loss in the millimeter wave spectrum. These beams are spa- tially confined, making millimeter wave links more resilient to eavesdropping and jamming attacks. However, the millimeter wave radios locate each other and establish communica- tion by exhaustively probing all possible angular directions, increasing their susceptibility to attacks. In this thesis, we showcase a secure beam management solution where we apply an adaptive beam management procedure that avoids probing the directions of potential attackers. We employ a reinforcement learning agent to control the probing and dynami- cally restrict sweeps to a subset of beams in the millimeter wave transmitter codebook to avoid the locations of potential attackers based on a proposed metric that quantifies the beam sweeping secrecy over a pre-defined area. We evaluate our proposed system through numerical simulations and an experimental real-life implementation on the CCI xG Testbed. / Master of Science / Millimeter wave systems leverage beamforming, a technique that's used to direct both trans- mission and reception of a signal to create narrow, high-powered beams that can overcome the signal deterioration that comes with millimeter wave spectrum. The spatially confined nature of these beams makes millimeter wave links resilient to eavesdropping and jamming attacks. However, the millimeter wave radios find each other and establish communication by searching every possible angular direction, which increases the potential for the millimeter wave radios to be attacked. In this thesis, we showcase a secure method of establishing this communication link that avoids looking in the direction of a potential attacker. We then employ an artificial intelligence capable of controlling this search by sweeping a subset of all possible directions in the millimeter wave transmitter codebook based on a proposed metric that quantifies the secrecy of communication. We evaluate our proposed system through numerical simulations and an experimental real-life implementation on the CCI xG Testbed.

In this Master's thesis entitled "Effectiveness Evaluation of Sfumato Metod of Initial Reading in Prevention of Dyslexia" we tried to find out, whether application of a certain teaching method of an initial reading eliminates presence of dyslexia. Thesis consists of a theoretical and a practical part. The theoretical part characterizes theoretical basis in the area of specific learning disabilities and education of initial reading with special focus on dyslexia issues and Sfumato Method of Initial Reading. The practical part is based on interviews and questionnaire surveys, which provides us possibility to compare methods of education of initial reading and evaluate them in context of development of specific learning disability - dyslexia. The thesis aims to evaluate of selected methods of education of initial reading in relation to prevention of specific disability of reading learning - dyslexia.