38 research outputs found
Aeronautical Engineering: A continuing bibliography, 1982 cumulative index
This bibliography is a cumulative index to the abstracts contained in NASA SP-7037 (145) through NASA SP-7037 (156) of Aeronautical Engineering: A Continuing Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, and report number indexes
Energy: A continuing bibliography with indexes
This bibliography lists 1096 reports, articles, and other documents introduced into the NASA Scientific and Technical Information System from April 1, 1979 through June 30, 1979
Energy: A continuing bibliography with indexes, issue 17
This bibliography lists 1292 reports, articles, and other documents introduced into the NASA scientific and technical information system from January 1, 1978 through March 31, 1978
Energy: A continuing bibliography with indexes, issue 32
This bibliography lists 1316 reports, articles, and other documents introduced into the NASA scientific and technical information system from October 1, 1981 through December 31, 1981
Management: A bibliography for NASA managers
This bibliography lists 731 reports, articles and other documents introduced into the NASA Scientific and Technical Information System in 1990. Items are selected and grouped according to their usefulness to the manager as manager. Citations are grouped into ten subject categories: human factors and personnel issues; management theory and techniques; industrial management and manufacturing; robotics and expert systems; computers and information management; research and development; economics, costs and markets; logistics and operations management; reliability and quality control; and legality, legislation, and policy
A cumulative index to the 1973 issues of Aeronautical engineering: A special bibliography
This publication is a cumulative index to the abstracts contained in NASA SP-7037 (28) through NASA SP-7037 (39) of Aeronautical Engineering: A Special Bibliography. NASA SP-7037 and its supplements have been compiled through the cooperative efforts of the American Institute of Aeronautics and Astronautics (AIAA) and the National Aeronautics and Space Administration (NASA). This cumulative index includes subject, personal author, corporate source, contract, and report number indexes
Proceedings of the NASA Conference on Space Telerobotics, volume 4
Papers presented at the NASA Conference on Space Telerobotics are compiled. The theme of the conference was man-machine collaboration in space. The conference provided a forum for researchers and engineers to exchange ideas on the research and development required for the application of telerobotic technology to the space systems planned for the 1990's and beyond. Volume 4 contains papers related to the following subject areas: manipulator control; telemanipulation; flight experiments (systems and simulators); sensor-based planning; robot kinematics, dynamics, and control; robot task planning and assembly; and research activities at the NASA Langley Research Center
Preliminary design of a shuttle docking and cargo handling system
For abstract, see N72-16756
Co-simulation techniques based on virtual platforms for SoC design and verification in power electronics applications
En las 煤ltimas d茅cadas, la inversi贸n en el 谩mbito energ茅tico ha aumentado considerablemente. Actualmente, existen numerosas empresas que est谩n desarrollando equipos como convertidores de potencia o m谩quinas el茅ctricas con sistemas de control de 煤ltima generaci贸n. La tendencia actual es usar System-on-chips y Field Programmable Gate Arrays para implementar todo el sistema de control. Estos dispositivos facilitan el uso de algoritmos de control m谩s complejos y eficientes, mejorando la eficiencia de los equipos y habilitando la integraci贸n de los sistemas renovables en la red el茅ctrica. Sin embargo, la complejidad de los sistemas de control tambi茅n ha aumentado considerablemente y con ello la dificultad de su verificaci贸n.
Los sistemas Hardware-in-the-loop (HIL) se han presentado como una soluci贸n para la verificaci贸n no destructiva de los equipos energ茅ticos, evitando accidentes y pruebas de alto coste en bancos de ensayo. Los sistemas HIL simulan en tiempo real el comportamiento de la planta de potencia y su interfaz para realizar las pruebas con la placa de control en un entorno seguro.
Esta tesis se centra en mejorar el proceso de verificaci贸n de los sistemas de control en aplicaciones de electr贸nica potencia. La contribuci贸n general es proporcionar una alternativa a al uso de los HIL para la verificaci贸n del hardware/software de la tarjeta de control. La alternativa se basa en la t茅cnica de Software-in-the-loop (SIL) y trata de superar o abordar las limitaciones encontradas hasta la fecha en el SIL.
Para mejorar las cualidades de SIL se ha desarrollado una herramienta software denominada COSIL que permite co-simular la implementaci贸n e integraci贸n final del sistema de control, sea software (CPU), hardware (FPGA) o una mezcla de software y hardware, al mismo tiempo que su interacci贸n con la planta de potencia. Dicha plataforma puede trabajar en m煤ltiples niveles de abstracci贸n e incluye soporte para realizar co-simulaci贸n mixtas en distintos lenguajes como C o VHDL.
A lo largo de la tesis se hace hincapi茅 en mejorar una de las limitaciones de SIL, su baja velocidad de simulaci贸n. Se proponen diferentes soluciones como el uso de emuladores software, distintos niveles de abstracci贸n del software y hardware, o relojes locales en los m贸dulos de la FPGA. En especial se aporta un mecanismo de sincronizaron externa para el emulador software QEMU habilitando su emulaci贸n multi-core. Esta aportaci贸n habilita el uso de QEMU en plataformas virtuales de co-simulacion como COSIL.
Toda la plataforma COSIL, incluido el uso de QEMU, se ha analizado bajo diferentes tipos de aplicaciones y bajo un proyecto industrial real. Su uso ha sido cr铆tico para desarrollar y verificar el software y hardware del sistema de control de un convertidor de 400 kVA
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Bespoke Security for Resource Constrained Cyber-Physical Systems
Cyber-Physical Systems (CPSs) are critical to many aspects of our daily lives. Autonomous cars, life saving medical devices, drones for package delivery, and robots for manufacturing are all prime examples of CPSs. The dual cyber/physical operating nature and highly integrated feedback control loops of CPSs means that they inherit security problems from traditional computing systems (e.g., software vulnerabilities, hardware side-channels) and physical systems (e.g., theft, tampering), while additionally introducing challenges of their own. The challenges to achieving security for CPSs stem not only from the interaction of the cyber and physical domains, but from the additional pressures of resource constraints imposed due to cost, limited energy budgets, and real-time nature of workloads. Due to the tight resource constraints of CPSs, there is often little headroom to devote for security. Thus, there is a need for low overhead deployable solutions to harden resource constrained CPSs. This dissertation shows that security can be effectively integrated into resource constrained cyber-physical system devices by leveraging fundamental physical properties, & tailoring and extending age-old abstractions in computing.
To provide context on the state of security for CPSs, this document begins with the development of a unifying framework that can be used to identify threats and opportunities for enforcing security policies while providing a systematic survey of the field. This dissertation characterizes the properties of CPSs and typical components (e.g., sensors, actuators, computing devices) in addition to the software commonly used. We discuss available security primitives and their limitations for both hardware and software. In particular, we focus on software security threats targeting memory safety. The rest of the thesis focuses on the design and implementation of novel, deployable approaches to combat memory safety on resource constrained devices used by CPSs (e.g., 32-bit processors and microcontrollers). We first discuss how cyber-physical system properties such as inertia and feedback can be used to harden software efficiently with minimal modification to both hardware and software. We develop the framework You Only Live Once (YOLO) that proactively resets a device and restores it from a secure verified snapshot. YOLO relies on inertia, to tolerate periods of resets, and on feedback to rebuild state when recovering from a snapshot. YOLO is built upon a theoretical model that is used to determine safe operating parameters to aid a system designer in deployment. We evaluate YOLO in simulation and two real-world CPSs, an engine and drone.
Second, we explore how rethinking of core computing concepts can lead to new fundamental abstractions that can efficiently hide performance overheads usually associated with hardening software against memory safety issues. To this end, we present two techniques: (i) The Phantom Address Space (PAS) is a new architectural concept that can be used to improve N-version systems by (almost) eliminating the overheads associated with handling replicated execution. Specifically, PAS can be used to provide an efficient implementation of a diversification concept known as execution path randomization aimed at thwarting code-reuse attacks. The goal of execution path randomization is to frequently switch between two distinct program variants forcing the attacker to gamble on which code to reuse. (ii) Cache Line Formats (Califorms) introduces a novel method to efficiently store memory in caches. Califorms makes the novel insight that dead spaces in program data due to its memory layout can be used to efficiently implement the concept of memory blacklisting, which prohibits a program from accessing certain memory regions based on program semantics. Califorms not onlyconsumes less memory than prior approaches, but can provide byte-granular protection while limiting the scope of its hardware changes to caches. While both PAS and Califorms were originally designed to target resource constrained devices, it's worth noting that they are widely applicable and can efficiently scale up to mobile, desktop, and server class processors.
As CPSs continue to proliferate and become integrated in more critical infrastructure, security is an increasing concern. However, security will undoubtedly always play second fiddle to financial concerns that affect business bottom lines. Thus, it is important that there be easily deployable, low-overhead solutions that can scale from the most constrained of devices to more featureful systems for future migration. This dissertation is one step towards the goal of providing inexpensive mechanisms to ensure the security of cyber-physical system software