<p>Modern reactors promise enhanced capabilities not previously possible including integration with the smart grid, remote monitoring, reduced operation and maintenance costs, and more efficient operation. . Modern reactors are designed for installation to remote areas and integration to the electric smart grid, which would require the need for secure undisturbed remote control and the implementation of two-way communications and advanced digital technologies. However, two-way communications between the reactor facility, the enterprise network and the grid would require continuous operation data transmission. This would necessitate a deep understanding of cybersecurity and the development of a robust cybersecurity management plan in all reactor communication networks. Currently, there is a limited number of testbeds, mostly virtual, to perform cybersecurity research and investigate and demonstrate cybersecurity implementations in a nuclear environment. To fill this gap, the goal of this thesis is the development of a real-time cyber-physical testbed with real operational and information technology data to allow for cybersecurity research in a representative nuclear environment. In this thesis, a prototypic cyber-physical testbed was designed, built, tested, and installed in PUR-1. The cyber-physical testbed consists of an Auxiliary Moderator Displacement Rod (AMDR) that experimentally simulates a regulating rod, several sensors, and digital controllers mirroring Purdue University Reactor One (PUR-1) operation. The cyber-physical testbed is monitored and controlled remotely from the Remote Monitoring and Simulation Station (RMSS), located in another building with no line of sight to the reactor room. The design, construction and testing of the cyber-physical testbed are presented along with its capabilities and limitations. The cyber-physical testbed network architecture enables the performance of simulated cyberattacks including false data injection and denial of service. Utilizing the RMSS setup, collected information from the cyber-physical testbed is compared with real-time operational PUR-1 data in order to evaluate system response under simulated cyber events. Furthermore, a physics-based model is developed and benchmarked to simulate physical phenomena in PUR-1 reactor pool and provide information about reactor parameters that cannot be collected from reactor instrumentation system.</p>

In this dissertation, we discuss the Distributed Spacecraft Attitude Control System Simulator (DSACSS) testbed developed at Virginia Polytechnic Institute and State University for the purpose of investigating various control techniques for single and multiple spacecraft. DSACSS is comprised of two independent hardware-in-the-loop simulators and one software spacecraft simulator. The two hardware-in-the-loop spacecraft simulators have similar subsystems as flight-ready spacecraft (e.g. command and data handling; communications; attitude determination and control; power; payload; and guidance and navigation). The DSACSS framework is a flexible testbed for investigating a variety of spacecraft control techniques, especially control scenarios involving coupled attitude and orbital motion. The attitude hardware simulators along with numerical simulations assist in the development and evaluation of Lyapunov based asymptotically stable, nonlinear attitude controllers with three reaction wheels as the control device. The angular rate controller successfully tracks a time varying attitude trajectory. The Modified Rodrigues Parmater (MRP) attitude controller results in successfully tracking the angular rates and MRP attitude vector for a time-varying attitude trajectory. The attitude controllers successfully track the reference attitude in real-time with hardware similar to flight-ready spacecraft. Numerical simulations and the attitude hardware simulators assist in the development and evaluation of a robust, asymptotically stable, nonlinear attitude controller with three reaction wheels as the actuator for attitude control. The MRPs are chosen to represent the attitude in the development of the controller. The robust spacecraft attitude controller successfully tracks a time-varying reference attitude trajectory while bounding system uncertainties. The results of a Global Positioning System (GPS) hardware-in-the-loop simulation of two spacecraft flying in formation are presented. The simulations involve a chief spacecraft in a low Earth orbit (LEO), while a deputy spacecraft maintains an orbit position relative to the chief spacecraft. In order to maintain the formation an orbit correction maneuver (OCM) for the deputy spacecraft is required. The control of the OCM is accomplished using a classical orbital element (COE) feedback controller and simulating continual impulsive thrusting for the deputy spacecraft. The COE controller requires the relative position of the six orbital elements. The deputy communicates with the chief spacecraft to obtain the current orbit position of the chief spacecraft, which is determined by a numerical orbit propagator. The position of the deputy spacecraft is determined from a GPS receiver that is connected to a GPS hardware-in-the-loop simulator. The GPS simulator creates a radio frequency (RF) signal based on a simulated trajectory, which results in the GPS receiver calculating the navigation solution for the simulated trajectory. From the relative positions of the spacecraft the COE controller calculates the OCM for the deputy spacecraft. The formation flying simulation successfully demonstrates the closed-loop hardware-in-the-loop GPS simulator. This dissertation focuses on the development of the DSACSS facility including the development and implementation of a closed-loop GPS simulator and evaluation of nonlinear feedback attitude and orbit control laws using real-time hardware-in-the-loop simulators. / Ph. D.

El objetivo de la tesis es definir una metodología de desarrollo de aplicaciones de tiempo real basadas en componentes, orientada a aplicaciones cuyos requisitos temporales se especifican utilizando un modelo reactivo de comportamiento temporal. La metodología se construye en base a extensiones que incorporan a las especificaciones, modelos de referencia y procesos estándares propios de la ingeniería de componentes convencionales, esto es, sin requisitos temporales, los datos y los procesos necesarios para la especificación, diseño y análisis de los aspectos relativos al comportamiento temporal. La metodología se sustenta en cuatro contribuciones principales:- Se propone la metodología de modelado modular del comportamiento temporal Mod-MAST, que permite construir el modelo de una aplicación basada en componentes por composición de los modelos de los componentes que la forman. - Se propone la extensión RT-D&C de la especificación Deployment and Configuration of Component-based Distributed Applications de OMG, que permite incluir metadatos relativos a comportamiento temporal en los descriptores de componentes, plataformas de ejecución y aplicaciones. - Se especifica la tecnología de componentes RT-CCM como una extensión de la especificación estándar Lightweight CCM de OMG, que añade los mecanismos necesarios para desarrollar aplicaciones con comportamiento temporal predecible.- Se propone la tecnología de componentes Ada-CCM como implementación concreta de RT-CCM basada en el lenguaje de programación Ada 2005.Todos estos elementos se integran en un proceso completo de diseño de tiempo real de aplicaciones basadas en componentes. / The objective of this work is to define a methodology for the development of real-time component-based applications, focused on applications whose timing requirements are specified according to a reactive model of the timing behaviour. The methodology is built through a set of extensions that incorporate to the standard specifications, reference models and processes typical from the conventional components engineering, i.e. components without timing requirements, the data structures and the processes required for the specification, design and analysis of the aspects related to timing behaviour. The methodology relies on four main contributions:- The Mod-MAST modular modelling methodology, which allows building the real-time model of a component-based application by composing the models of the components that form it.- The RT-D&C extension of the Deployment and Configuration of Component-based Distributed Applications Specification of the OMG, which allows including metadata related to timing behaviour in the descriptors of components, execution platforms and applications.- The RT-CCM components technology, which is an extension of the standard Lightweight CCM Specification of the OMG that incorporates mechanisms to develop applications with predictable timing behaviour.- The Ada-CCM components technology has been developed. It is an implementation of the RT-CCM technology based on the Ada 2005 programming language.All these elements have been integrated in a complete real-time design process for component-based applications.

Made available in DSpace on 2014-07-29T15:01:40Z (GMT). No. of bitstreams: 1 maria margareth goncalves.pdf: 3073051 bytes, checksum: a405b4aae069912b1212db181d1858f8 (MD5) Previous issue date: 2008-08-04 / Industrial activities are constantly producing wastes such as dyes which are usually found in the industrial effluents and constitutes a environmental problem due its toxicity and inadequate disposal. The use of fungi, in particular the white-rot fungus, have been found to be efficient for biodegrading these compounds. In addition, slow sand filtration have been reported to be the most efficient unit filtration processes to improve the physical, biological and chemical quality of potable water. The objective of this work was to investigate the removal efficiency of the dye FD&C azul Nº 2 Indigotina, by the use of the Trametes versicolor fungus combined with slow sand filtration. Two laboratory-scale filter columns of 0.08 m diameter and 0.90 m sand media depth were used to investigate the process performance. One slow sand filter, FLA, was applied in combination with the Trametes versicolor fungus, while the FLB was used as control. Three methodologies for the fungi growth were used. The results showed that the slow sand filtration is a prominent process for the removal of the dye FD&C azul nº 2 Indigotina when used in combination with the Trametes versicolor fungus. A maximum removal of 95% was found when the filter was inoculated with fungi grown on Petri dish. The average dye removal when the increased fungi biomass was inoculated to the filter was 70%. This result suggests that the filter performance increased when the fungus was inoculated with fungi grown on Petri dish. In addition, head loss was found to be higher in the FLA filter than in the FLA (control), indicating that the fungi biomass contributes to the head loss development. / Nas atividades industriais geradoras de resíduos os corantes são amplamente encontrados nos efluentes, quase sempre, constituindo um problema de ordem ambiental devido à sua toxicidade. O uso de fungos na degradação de corantes vem sendo estudado em diversos trabalhos científicos enquanto as vantagens econômicas e ambientais do uso de filtros lentos na produção de água bacteriologicamente segura há muito tempo já está descrita por diversos autores. Este trabalho teve por objetivo investigar a eficiência da remoção de corante artificial FD&C azul nº2 Indigotina, com uso do fungo de degradação branca Trametes versicolor em combinação com a filtração lenta. Para isso, foram instalados dois protótipos de filtros lentos denominados FL-A e FL-B em escala laboratorial, sendo que o filtro FL-A, foi inoculado com o fungo e o filtro FL-B, utilizado como controle, não foi inoculado com fungo. Três procedimentos foram empregados para o cultivo do fungo. Os resultados mostraram que a filtração lenta tem grande potencial para remoção eficiente de cor quando empregada em conjunto com o fungo Trametes versicolor. O melhor percentual de remoção do corante FD&C azul nº2 indigotina pelo fungo Trametes versicolor em combinação com a filtração lenta foi de 95% na metodologia com adição da biomassa de cultivo do fungo correspondente a duas placas de Petri. A média de descoramento da metodologia com adição de biomassa aumentada do fungo foi de 70%. Em todas as carreiras de filtração as perdas de cargas no FL-A, inoculado com fungo, foram superiores às do FL-B de controle. Este resultado indica que a biomassa gerada pelos fungos contribue para o aumento da perda de carga nos filtros lentos.

By placing millions of space sunshades, of the order of 104 m2 at the sub-Lagrangian point L1',between the sun and Earth, solar radiation can be reduced enough to achieve the necessary temper-ature reduction to enable a slow down of the global warming. The vast amount of space sunshadesposes significant challenges on the communication system, as the probability of interference, whichcan distort information, increases with the number of simultaneously communicating units.This thesis aims to design a potential structure for the communication system that minimizesinterference as much as possible. To reduce the number of simultaneously communicating units, thesunshades are arranged in cell formation, where a mother is placed in the center with daughtersaround that only communicate with their specific cell mother. Direct communication betweenthe Earth and space sunshades is not possible as the interference from solar radiation can causesignificant distortion on the signals. Therefore, relay satellites are placed in orbit around thesub-Lagrangian point L1' at a sufficient distance to avoid the effects of solar radiation. Thus, thecommunication between the mothers and Earth is instead routed via the relay satellites. Sincecommunication between such a large number of entities in space has not been investigated before,this approach could provide a possible basic design framework for designing such infrastructure inthe future.