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The smart power grid blends the bidirectional energy with information flow. Compared to the traditional power grid, it requires more intelligent and faster control, protection, automation, and communication techniques. Ultimately, power system protection, fault location, and isolation have to go through an immense modernization process since the previously used protection techniques are no longer usable in the smart grid. This is due to the bidirectional flow of energy and dynamics of the network configuration in the smart grid. Multiagent Systems (MAS) techniques can enable the power system to become smarter, reliable, self-healing, and robust. Its decentralized nature and operational robustness make the MAS application a leading technology. In this paper, the MAS architecture that suits the smart grid application is proposed. Besides, a detailed systematic review on the application of MAS to smart grid protection is conducted. The MAS application for self-healing of the smart grid through Fault Location, Isolation, and Service Restoration (FLISR) is also investigated. Furthermore, based on the MAS architecture, fault identification technique, simulation, and verification methods implemented, a comparison is made among the ongoing research activities on power system protection and FLISR. Consequently, the research gap on power system protection, FLISR, and self-healing is indicated. Finally, the use of IEC 61850 for implementing the MAS technique is discussed. As a result, the use of MAS for adaptive smart grid protection, the challenges in the implementation of the communication among the agents and outside laboratory application of the MAS for the power systems are the research topics that require further work. © 2021 Elsevier Ltd

Tesis. Defendida en 2017. Carpetas [1-4]: Curriculum ; Resumen ; Palabras clave ; Tesis Las FPGAs (Field Programmable Gate Arrays), como dispositivos reconfigurables, tienen un cada vez mayor uso, y su popularidad está creciendo hasta superar a los circuitos de propósito específico (ASICs), debido fundamentalmente a su adaptabilidad, capacidades lógicas, velocidad y potencia en procesado de señal. De esta manera, las FPGAs también están viendo aumentada su presencia en aplicaciones espaciales. Si bien las primeras FPGAs eran dispositivos muy sencillos, los dispositivos actuales se han convertido en subsistemas propios de las aplicaciones en las que están integradas, combinando una alta potencial y funcionalidad en un único chip. Hablando de aplicaciones espaciales, las proyecciones futuras predicen que el tiempo de vida de las misiones se alargará más allá de los diez años, y la capacidad de reprogramación (algo intrínseco en las FPGAs basadas en tecnología SRAM o flash) se convertirá en un requisito imprescindible. Un problema importante de las FPGAs reprogramables es que son sensibles a los entornos de radiación. Los sistemas en aplicaciones espaciales se diferencian respecto a sus equivalente en aplicaciones terrestres en que los primeros son mucho más susceptibles de sufrir "bit flips" en las memorias o fallos por ionización en el semiconductor, inducidos por efectos de la radiación. Las FPGAs basadas en tecnología SRAM y flash presentan una resistencia relativamente buena a dosis total por ionización (TID), pero son muy sensibles a errores temporales producidas por partículas energéticas. En contra de lo que pasa con las FPGAs endurecidas mediante procesos de fabricación, las SRAM FPGAs tienen que ser protegidas mediante técnicas de mitigación que mejoren la fiabilidad del diseño. Hasta que el desarrollo de estas técnicas ha sido un hecho aceptado por la comunidad científica, los errores producidos por la radiación en estos dispositivos eran muchas veces obviados, por lo que las FPGAs reprogramables tuvieron inicialmente un grado de éxito moderado. Pero a partir de que las FPGAs ganaran una mayor consideración, y por lo tanto se empezaran a usar técnicas de mitigación apropiadas, estos dispositivos se han convertido en un elemento clave de las misiones espaciales, ofreciendo un gran rendimiento y altos niveles de éxito. Debido al escalado en las nuevas familias tecnológicas, y las cada vez más fuertes restricciones en frecuencia y capacidad de proceso, el efecto de la radiación en los circuitos se va agravando. De esta manera, los errores múltiples que afectan simultáneamente a más de un bit (MBU/MCU) están adquiriendo un protagonismo creciente frente a los SEU tradicionales. Por lo tanto, existe una necesidad cada vez mayor de técnicas de mitigación capaces de detectar y corregir no solo errores individuales, sino también múltiples. Todo esto respetando las restricciones temporales de funcionamiento de los diseños implementados en las FPGAs, de las memorias de alta velocidad y de las interfaces de datos. A la vista de todo lo expuesto, en esta tesis se van a presentar códigos de corrección de errores (ECC) para errores individuales y múltiples, pero que además presentan una velocidad de proceso suficientemente alta como para respetar las restricciones temporales comentadas anteriormente. De esta manera, se van a extender, rediseñar, combinar y optimizar diferentes ECC con el fin de:1) Mejorar su rendimiento en área y tiempo 2) Cubrir las necesidades específicas de ciertas aplicaciones. Por ejemplo, los codificadores y decodificadores OS-MLD (One Step - Majority Logic Decodable) se pueden implementar eficientemente en FPGAs, ya que las sólidas capacidades de mitigación de estos códigos, junto con su bajo overhead de tiempo y su reducida complejidad, hacen que sean una alternativa atractiva para proteger los diseños implementados en estos dispositivos. En resumen, en este trabajo se van a presentar técnicas de mitigación generales y específicas, basadas en ECC, junto con casos de estudio que pongan de manifiesto las ventajas de dichas técnicas en cuanto a su efectividad, todo ello con el f. Abstract: Field Programmable Gate Arrays (FPGAs) have a broad usage area and are becoming more and more popular over ASICs, due to their features like flexibility, logic capabilities, speed and signal processing power. Conventional FPGAs offering these features are increasingly popular for space applications. From simple glue logic, the application of FPGAs has moved to complete subsystem platforms combining several real-time functions on a single chip, even including microprocessors and memories. Current applications and future projections show that satellite lifetimes will be extended beyond ten years and re-programmability, a significant feature of SRAM or flash-based FPGAs, will become an absolute requirement. An issue is that reprogrammable FPGAs are sensitive to the radiation environment. Compared to terrestrial systems, space systems operate in a harsh radiation environment and are more likely to suffer from bit flips in memory elements or ionization failure in the semiconductor induced by radiation. Commercial or industrial grade SRAM and flash based FPGAs have relatively good total dose resistance, but they are prone to energized particle induced bit upsets. Mitigation techniques should be taken into consideration in order to improve reliability of the design, whereas Rad-Hard FPGAs are hardened by design techniques at the physical level during manufacturing. Until the development of successful error mitigation techniques, radiation-induced errors were not taken into consideration, and reprogrammable FPGAs had been used at space missions with a mixed level of success. When the advantages of FPGAs are taken into consideration, with the use of proper mitigation techniques against vulnerability to radiation environments, FPGAs have become a key element of space mission with high performance and success. As well as for FPGAs, there is also a need for mitigating peripherals that are used in designs in conjunction with FPGAs, like high – speed memories and data interfaces. The downscaling of process technology enables higher operating frequencies, data throughput, logic capacities, but on the other hand the characterization of upsets changes. Multiple Bit / Cell Upsets are becoming the major concern in addition to Single Bit Upsets. So, there is a need for mitigation techniques that must be capable of correcting and detecting single or multi-bit errors while preventing violation of timing specifications of FPGA designs, high-speed memories and data interfaces. In this thesis, single/multi-bit error correcting and low delay Error Correction Codes(ECCs) are proposed as mitigating techniques targeting specific FPGA blocks (registers, BRAM), high-speed memories and data interfaces. While achieving a sufficient mitigation level, different types of ECCs are extended, redesigned, combined or optimized for: 1) improving performance regarding area and timing 2) application specific needs. Encoders and decoders of One Step Majority Logic Decodable (OS-MLD) codes and schemes based on these codes can be efficiently implemented on FPGAs. Also, they present a substantial level of mitigation, low delay, and low complexity. All of these features combined make OS-MLD ECCs attractive for mitigating user logic implemented on FPGAs. This work includes general and application specific mitigation techniques composed of ECCs. Case studies and tests support proposed techniques and implementations to examine effectiveness and coverage. The outcome of this work is a set of mitigation techniques recommended to be used in conjunction with commercial or industrial grade FPGAs. Ordenador con navegador de Internet ; Adobe Acrobat Reader 185 p. (Según el contador de la aplicación)

Virtual network embedding (VNE) is defined as the allocation of network resources to multiple virtual networks (VNs) and is recognized to be a challenging task to perform efficiently. Virtual network survivability is a new term that describes the measures taken to provide a failure-proof VN against physical link and/or node failure. Indeed, a single link or node failure in a substrate network can bring down multiple hosted VNs, i.e., the ones that utilize that failed link or node. As such, virtual network survivability becomes an essential part of VNE. While much work has been dedicated to studying the impact of a variety of failure cases in a VN, little attention has been directed towards studying the link failure impact on multicast virtual network (MVN) applications, which principally restrict end-to-end delay and delay variation measures. In fact, most of the introduced survivability schemes adopt protection techniques by reserving backup resources prior to embedding, which inevitably leads to under-utilization of the network resources. In this paper, we first investigate the impact of physical link failure on MVNs. Then, we introduce a novel recovery approach to restore MVNs while considering their end-delay and delay variation requirements. Simulation experiments prove that our recovery technique achieves good restoration ratio in considerably fast execution time and low link mapping cost with little impact on the admittance ratio. Scopus

Total Cost of Ownership (TCO) is a key optimization metric for the design of a datacenter. This paper proposes, for the first time, a framework for modeling the implications of DRAM failures and DRAM error protection techniques on the TCO of a datacenter. The framework captures the Effects and interactions of several key parameters including: the choice of DRAM protection technique (e.g. single vs dual channel Chipkill), device width (x4 or x8), memory size, power, FITs for various failure modes, the performance, power and temperature overheads of a protection technique for a given service and mixes of collocated services. The usefulness of the proposed framework is demonstrated through several case studies that identify the best DRAM protection technique in each case, in terms of TCO. Interestingly, our analysis reveals that among the three DRAM protection techniques considered, there is no one that is always superior to all the others. Moreover, each technique is better than the others for some cases. This underlines the importance and the need of the proposed framework for making optimal memory protection datacenter design decisions. As part of this work, we analyze and report the performance and power with single channel and dual channel Chipkill on real hardware when running a web search benchmark alone and collocated with benchmarks of varying memory intensity. This analysis reveals that the choice of memory protection can have serious performance and TCO ramifications depending on the memory characteristics of collocated services. Other analysis reveals that, for the datacenter and services assumed in this study, when using Chipkill protection it can be beneficial for TCO to use DRAM with 100x the failure rate of a baseline DRAM as long as the cost per DIMM is at least a dollar less compared to the baseline. © 2015 ACM. 05-09-December-2015 572 584 Sponsors: ARM et al. IBM Intel Microsoft NetApp Conference code: 119360 Cited By :2

El gas radón es un elemento radiactivo que se presenta en la naturaleza por la desintegración del radio contenido en los suelos terrestres. Este gas es capaz de viajar entre los poros del terreno y penetrar en los edificios, donde podrá aumentar su concentración y constituir un riesgo para la salud sus ocupantes por la inhalación del mismo. La Organización Mundial de la Salud califica el radón como agente cancerígeno de grado 1. Según este organismo, el radón es la segunda causa de contracción de cáncer pulmonar detrás del tabaco. En base a la percepción del riesgo derivada de estudios epidemiológicos, algunos países han establecido unos valores de concentración de radón como límites de seguridad, por encima de los cuales se recomienda o se obliga, según el caso, a una intervención arquitectónica para reducir los niveles.Desde una perspectiva arquitectónica, se han venido estudiando diversas técnicas constructivas destinadas a frenar la inmisión de radón hacia el interior de los edificios o a evacuar el mismo, con el fin de disminuir la concentración por debajo de los límites de seguridad. Este artículo desarrolla las distintas estrategias constructivas que se vienen usando para estos fines, algunas de las cuales han sido ensayadas en España gracias a un proyecto de investigación subvencionado por el Consejo de Seguridad Nuclear, y desarrollado por el Instituto Eduardo Torroja y la Universidad de Cantabria. Radon gas is a radioactive element that appears in nature by the decay of radium found in terrestrial soils. This gas is able to travel between the pores of the ground and enter into the buildings where the concentration can increase and becoming a health risk to occupants from inhaling. The World Health Organization rate the radon gas as a level 1 carcinogen agent. According to this organization, radon is the second leading cause of lung cancer contraction after tobacco. Based on the perception of risk derived from epidemiological medical studies, some countries have established radon concentration values as safety limits, above which is recommended or required an architectural intervention to reduce levels. From an architectural perspective, there have been studies of several radon protection techniques to reduce radon immission in buildings or to evacuate it, in order to reduce the radon levels below the safety limits. This article develops some protection strategies that have been being used for these purposes, some of which have been tested in Spain thanks to a research project funded by the Nuclear Safety Council, and developed by the Eduardo Torroja Institute and the University of Cantabria.

Radon gas is a radioactive element that appears in nature by the decay of radium found in terrestrial soils. This gas is able to travel between the pores of the ground and enter into the buildings where the concentration can increase and becoming a health risk to occupants from inhaling. The World Health Organization rate the radon gas as a level 1 carcinogen agent. According to this organization, radon is the second leading cause of lung cancer contraction after tobacco. Based on the perception of risk derived from epidemiological medical studies, some countries have established radon concentration values as safety limits, above which is recommended or required an architectural intervention to reduce levels. From an architectural perspective, there have been studies of several radon protection techniques to reduce radon immission in buildings or to evacuate it, in order to reduce the radon levels below the safety limits. This article develops some protection strategies that have been being used for these purposes, some of which have been tested in Spain thanks to a research project funded by the Nuclear Safety Council, and developed by the Eduardo Torroja Institute and the University of Cantabria. El gas radón es un elemento radiactivo que se presenta en la naturaleza por la desintegración del radio contenido en los suelos terrestres. Este gas es capaz de viajar entre los poros del terreno y penetrar en los edificios, donde podrá aumentar su concentración y constituir un riesgo para la salud sus ocupantes por la inhalación del mismo. La Organización Mundial de la Salud califica el radón como agente cancerígeno de grado 1. Según este organismo, el radón es la segunda causa de contracción de cáncer pulmonar detrás del tabaco. En base a la percepción del riesgo derivada de estudios epidemiológicos, algunos países han establecido unos valores de concentración de radón como límites de seguridad, por encima de los cuales se recomienda o se obliga, según el caso, a una intervención arquitectónica para reducir los niveles.Desde una perspectiva arquitectónica, se han venido estudiando diversas técnicas constructivas destinadas a frenar la inmisión de radón hacia el interior de los edificios o a evacuar el mismo, con el fin de disminuir la concentración por debajo de los límites de seguridad. Este artículo desarrolla las distintas estrategias constructivas que se vienen usando para estos fines, algunas de las cuales han sido ensayadas en España gracias a un proyecto de investigación subvencionado por el Consejo de Seguridad Nuclear, y desarrollado por el Instituto Eduardo Torroja y la Universidad de Cantabria.

This paper focuses the fire performance of timber and timber structures and discusses possible approaches to mitigate the fire risk in timber buildings, with special relevance to the case of timber roofs. Furthermore, it highlights a number of issues concerning the implications for timber durability and mechanical properties resulting from the exposure to fire itself and high temperatures, active fire protection equipment and firefighting tactics, namely those involving the use of water, and passive fire protection measures, namely fire retardant treatments. These issues need be considered by those involved in the assessment and safeguard of ancient timber buildings. 7p DE/NEM 2009 7 a 10 de Outubro