A study of the selection of microcomputer architectures to automate planetary spacecraft power systems

Performance and reliability models of alternate microcomputer architectures as a methodology for optimizing system design were examined. A methodology for selecting an optimum microcomputer architecture for autonomous operation of planetary spacecraft power systems was developed. Various microcomputer system architectures are analyzed to determine their application to spacecraft power systems. It is suggested that no standardization formula or common set of guidelines exists which provides an optimum configuration for a given set of specifications

Efficient restoration of simultaneous transport services within an NFV infrastructure

Proceedings of: IEEE Global Communications Conference (GLOBECOM), 7-11 Dec. 2021, Madrid, Spain.In 5G networks, heterogeneous vertical services with different requirements are rolled out over a common multi-technology infrastructure. A resource orchestrator entity automatically coordinates the operations and functions to support the service's lifecycle management (i.e., creation, update and termination). Moreover, it is essential that service needs are continuously assured even if transport network anomalies (e.g., link failures) occur. Herein, we present an implemented resource orchestrator architecture integrating monitoring capabilities to attain closed-loop operations for: i) gathering monitored information; ii) detecting transport network anomalies; and iii) triggering the required action (e.g., restoration) to keep the service continuity. When a link failure happens, several transport services may be disrupted requiring to be immediately restored. To this end, we propose a novel on-line restoration algorithm called as Global Concurrent Optimization (GCO). The GCO algorithm aims at attaining an enhanced restorability performance compared to a more traditional restoration algorithm (referred to as 1-by-1). Both algorithms are experimentally compared on top of the deployed resource orchestrator architecture. The evaluation is done upon both dynamic service arrival/departure and link failure generation using different performance metrics: the average restorability, the average network resource utilization, and the restoration computational time.Work supported in part by EU Commission H2020 5Growth project (Grant No. 856709), Spanish MICINN AURORAS (RTI2018-099178-B-I00) and Spanish MINECO 5G-REFINE (TEC2017-88373-R) projects and Generalitat de Catalunya grant 2017 SGR 1195

An integrated diagnostic architecture for autonomous robots

Abstract unavailable please refer to PD

The Performance of Measurement-Based Overlay Networks

The literature contains propositions for the use of overlay networks to supplement the normal IP routing functions with higher-level information in order to improve aspects of network behavior. We consider the use of such an overlay to optimize the end-to-end behavior of some special tra c ows. Measurements are used both to construct the virtual links of the overlay and to establish the link costs for use in a link-state routing protocol. The overlay attempts to forward certain packets over the least congested rather than the shortest path. We present simulation results showing that contrary to common belief overlay networks are not always bene cial and can be detrimental

The planning coordinator: A design architecture for autonomous error recovery and on-line planning of intelligent tasks

Developing a robust, task level, error recovery and on-line planning architecture is an open research area. There is previously published work on both error recovery and on-line planning; however, none incorporates error recovery and on-line planning into one integrated platform. The integration of these two functionalities requires an architecture that possesses the following characteristics. The architecture must provide for the inclusion of new information without the destruction of existing information. The architecture must provide for the relating of pieces of information, old and new, to one another in a non-trivial rather than trivial manner (e.g., object one is related to object two under the following constraints, versus, yes, they are related; no, they are not related). Finally, the architecture must be not only a stand alone architecture, but also one that can be easily integrated as a supplement to some existing architecture. This thesis proposal addresses architectural development. Its intent is to integrate error recovery and on-line planning onto a single, integrated, multi-processor platform. This intelligent x-autonomous platform, called the Planning Coordinator, will be used initially to supplement existing x-autonomous systems and eventually replace them

Unattended network operations technology assessment study. Technical support for defining advanced satellite systems concepts

The results are summarized of an unattended network operations technology assessment study for the Space Exploration Initiative (SEI). The scope of the work included: (1) identified possible enhancements due to the proposed Mars communications network; (2) identified network operations on Mars; (3) performed a technology assessment of possible supporting technologies based on current and future approaches to network operations; and (4) developed a plan for the testing and development of these technologies. The most important results obtained are as follows: (1) addition of a third Mars Relay Satellite (MRS) and MRS cross link capabilities will enhance the network's fault tolerance capabilities through improved connectivity; (2) network functions can be divided into the six basic ISO network functional groups; (3) distributed artificial intelligence technologies will augment more traditional network management technologies to form the technological infrastructure of a virtually unattended network; and (4) a great effort is required to bring the current network technology levels for manned space communications up to the level needed for an automated fault tolerance Mars communications network

Assessing and augmenting SCADA cyber security: a survey of techniques

SCADA systems monitor and control critical infrastructures of national importance such as power generation and distribution, water supply, transportation networks, and manufacturing facilities. The pervasiveness, miniaturisations and declining costs of internet connectivity have transformed these systems from strictly isolated to highly interconnected networks. The connectivity provides immense benefits such as reliability, scalability and remote connectivity, but at the same time exposes an otherwise isolated and secure system, to global cyber security threats. This inevitable transformation to highly connected systems thus necessitates effective security safeguards to be in place as any compromise or downtime of SCADA systems can have severe economic, safety and security ramifications. One way to ensure vital asset protection is to adopt a viewpoint similar to an attacker to determine weaknesses and loopholes in defences. Such mind sets help to identify and fix potential breaches before their exploitation. This paper surveys tools and techniques to uncover SCADA system vulnerabilities. A comprehensive review of the selected approaches is provided along with their applicability

Algorithmic and combinatorial problems on multi-UAV systems

Mathematics has always been a fundamental piece in robotics and, research in robotics has played an important role in the development of mathematics. This thesis is motivated by the growing interest on problems that appear in aerial robotics applications, specifically, on cooperative systems of multiple aerial robots or drones. Most of the research works in multi-robot systems have focused primarily on construction and validation of working systems, rather than more general and formal analysis of problems and solutions. By contrast, this thesis focuses on formally solving problems of aerial multi-robot systems from a discrete and combinatorial optimization perspective. Inspired on problems of this area, the thesis introduces some new theoretical models and problems of interest for mathematicians and computer scientists. The following topics are covered in this thesis: (1) synchronization: design of a coordination strategy to allow periodical communication between the members of a cooperative team while performing a task along fixed trajectories in a scenario with limited communication range, (2) robustness: analysis of the detrimental effects in the performance of a synchronized system when one or more robots fail, (3) stochastic strategies: performance analysis of a synchronized system using drones with stochastic decision making, and (4) task allocation: decentralized coordination to perform periodical task allocation in order to maintain a balanced work load for all members of a team with limited communication range. In the first part of the thesis, we study the synchronization problem giving a theoretical characterization of the solutions and, we present an algorithm to build a synchronized system for a given set of covering trajectories. The second part focuses on the study of the robustness in a synchronized system regarding to two key aspects: covering of the working area and communication between the members of the team. We rigorously study several combinatorial problems to measure how robust a system is to deal with drones failures. Connections of theseproblemswithnumbertheory, graphtheory, circulantgraphsandpolynomial multiplication are shown. The third part is devoted to an analysis of synchronized systems using random aerial robots. This topic is closely related to the random walk theory. It is shown that stochastic strategies increase the robustness of a synchronized system. Finally, this thesis introduces the block sharing strategy to addresstheproblemofmaintainingabalancedtaskallocationamongtherobotsby using periodical communications. A proof on the convergence to an optimal task allocation is given and, a case study for structure construction using a cooperative team of aerial robots is presented. All algorithms developed in this thesis have been implemented and extensive experiments have been conducted to analyze and validate the proposed methods.Las matemáticas siempre han sido una pieza fundamental en el desarrollo de la robótica, así como los problemas de robótica han jugado un importante papel en el desarrollo de las matemáticas. Esta tesis está motivada por el creciente interés en problemas que aparecen en aplicaciones de robótica aérea, específicamente, está enfocada en sistemas cooperativos de múltiples robots aéreos o drones. La mayoría de los trabajos de investigación en sistemas de robots se han centrado en la construcción y validación de arquitecturas desde un enfoque empírico. Por el contrario, esta tesis enfoca el estudio de problemas relacionados con tareas para equipos de robots aéreos desde el punto de vista de la optimización discreta y combinatoria. Inspirada en problemas de este campo, esta memoria plantea nuevos modelos teóricos y problemas de interés para las matemáticas aplicadas y la ciencia computacional. Enestatesisse abordanlostemassiguientes: (1) sincronización: diseñodeuna estrategia de coordinación que permita comunicación periódica entre los miembros de un equipo cooperativo mientras ejecutan una tarea sobre trayectorias fijadas, (2) robustez: análisis del efecto que produce el fallo de los agentes en un sistema sincronizado, (3)estrategias estocásticas: análisisdelfuncionamientodeunsistema sincronizado cuando se utilizan drones con toma de decisiones aleatorias, y (4) asignación de tareas: coordinación no centralizada usando asignación periódica de tareas que permita mantener una carga de trabajo balanceada. En la primera parte, se estudia teóricamente el problema de la sincronización, dando condiciones necesarias y suficientes para la existencia de solución y se presenta un algoritmo que construye un sistema sincronizado para un conjunto fijado de trayectorias de vuelo. La segunda parte de la tesis estudia la robustez de un sistema sincronizado teniendo en cuenta dos aspectos fundamentales: el cubrimiento del terreno y la comunicación entre los miembros del equipo. Se estudian de forma rigurosa problemas combinatorios que surgen cuando se requiere saber cómo de robusto es un sistema con respecto a fallos. Se muestran conexiones con áreas matemáticas como la teoría de números, la teoría de grafos, los grafos circulantes o multiplicación de polinomios. En la tercera parte de la tesis, se estudia la robustez del sistema cuando se introducen decisiones aleatorias de los drones. Se prueba la relación de este problema con la teoría de caminatas aleatorias y se muestra que el uso de estrategias estocásticas supone una mejora de la robustez del sistema sincronizado. Por último, se propone la estrategia de coordinación por bloques para la asignación balanceada de tareas. Se prueba la convergencia del método a una asignación óptima y se realiza un estudio de caso para la construcción de una estructura mediante un equipo cooperativo de drones. Todos los algoritmos desarrollados en esta tesis han sido implementados y se han llevado a cabo diversos experimentosque demuestran la validez de los métodos propuestos