Passive available bandwidth: Applying self -induced congestion analysis of application-generated traffic

Monitoring end-to-end available bandwidth is critical in helping applications and users efficiently use network resources. Because the performance of distributed systems is intrinsically linked to the performance of the network, applications that have knowledge of the available bandwidth can adapt to changing network conditions and optimize their performance. A well-designed available bandwidth tool should be easily deployable and non-intrusive. While several tools have been created to actively measure the end-to-end available bandwidth of a network path, they require instrumentation at both ends of the path, and the traffic injected by these tools may affect the performance of other applications on the path.;We propose a new passive monitoring system that accurately measures available bandwidth by applying self-induced congestion analysis to traces of application-generated traffic. The Watching Resources from the Edge of the Network (Wren) system transparently provides available bandwidth information to applications without having to modify the applications to make the measurements and with negligible impact on the performance of applications. Wren produces a series of real-time available bandwidth measurements that can be used by applications to adapt their runtime behavior to optimize performance or that can be sent to a central monitoring system for use by other or future applications.;Most active bandwidth tools rely on adjustments to the sending rate of packets to infer the available bandwidth. The major obstacle with using passive kernel-level traces of TCP traffic is that we have no control over the traffic pattern. We demonstrate that there is enough natural variability in the sending rates of TCP traffic that techniques used by active tools can be applied to traces of application-generated traffic to yield accurate available bandwidth measurements.;Wren uses kernel-level instrumentation to collect traces of application traffic and analyzes the traces in the user-level to achieve the necessary accuracy and avoid intrusiveness. We introduce new passive bandwidth algorithms based on the principles of the active tools to measure available bandwidth, investigate the effectiveness of these new algorithms, implement a real-time system capable of efficiently monitoring available bandwidth, and demonstrate that applications can use Wren measurements to adapt their runtime decisions

State-of-the-art integration of decentralized energy management systems into the German smart meter gateway infrastructure

The German Smart Meter Gateway (SMGW) infrastructure enables digital access to metering data and distributed energy resources by external parties. There are, however, various restrictions in order to guarantee the privacy of consumers, and strong security requirements. Furthermore, in the current state of development, there are still several challenges to overcome in order to implement demand side management (DSM) measures. In this paper, we present a prototype enabling DSM measures within the SMGW infrastructure, using the smart grid traffic light concept. The prototype implements an automated decentralized energy management system (EMS) that optimally controls an electric vehicle charging station. In the development of this prototype, we did not only evaluate five of the seven available SMGW devices, but also push the limits of the infrastructure itself. The experiments demonstrated the successful implementation of the intended DSM measure by the EMS. Even though there are technical guidelines standardizing the functionality of SMGWs, our evaluation shows that there are substantial differences between the individual SMGW devices

Advanced photonic and electronic systems - WILGA 2017

WILGA annual symposium on advanced photonic and electronic systems has been organized by young scientist for young scientists since two decades. It traditionally gathers more than 350 young researchers and their tutors. Ph.D students and graduates present their recent achievements during well attended oral sessions. Wilga is a very good digest of Ph.D. works carried out at technical universities in electronics and photonics, as well as information sciences throughout Poland and some neighboring countries. Publishing patronage over Wilga keep Elektronika technical journal by SEP, IJET by PAN and Proceedings of SPIE. The latter world editorial series publishes annually more than 200 papers from Wilga. Wilga 2017 was the XL edition of this meeting. The following topical tracks were distinguished: photonics, electronics, information technologies and system research. The article is a digest of some chosen works presented during Wilga 2017 symposium. WILGA 2017 works were published in Proc. SPIE vol.10445

Replication for Web Hosting Systems

Replication is a well-known technique to improve the accessibility of Web sites. It generally offers reduced client latencies and increases a site’s availability. However, applying replication techniques is not trivial, and various Content Delivery Networks (CDNs) have been created to facilitate replication for digital content providers. Th

Wide-Area Situation Awareness based on a Secure Interconnection between Cyber-Physical Control Systems

Posteriormente, examinamos e identificamos los requisitos especiales que limitan el diseño y la operación de una arquitectura de interoperabilidad segura para los SSC (particularmente los SCCF) del smart grid. Nos enfocamos en modelar requisitos no funcionales que dan forma a esta infraestructura, siguiendo la metodología NFR para extraer requisitos esenciales, técnicas para la satisfacción de los requisitos y métricas para nuestro modelo arquitectural. Estudiamos los servicios necesarios para la interoperabilidad segura de los SSC del SG revisando en profundidad los mecanismos de seguridad, desde los servicios básicos hasta los procedimientos avanzados capaces de hacer frente a las amenazas sofisticadas contra los sistemas de control, como son los sistemas de detección, protección y respuesta ante intrusiones. Nuestro análisis se divide en diferentes áreas: prevención, consciencia y reacción, y restauración; las cuales general un modelo de seguridad robusto para la protección de los sistemas críticos. Proporcionamos el diseño para un modelo arquitectural para la interoperabilidad segura y la interconexión de los SCCF del smart grid. Este escenario contempla la interconectividad de una federación de proveedores de energía del SG, que interactúan a través de la plataforma de interoperabilidad segura para gestionar y controlar sus infraestructuras de forma cooperativa. La plataforma tiene en cuenta las características inherentes y los nuevos servicios y tecnologías que acompañan al movimiento de la Industria 4.0. Por último, presentamos una prueba de concepto de nuestro modelo arquitectural, el cual ayuda a validar el diseño propuesto a través de experimentaciones. Creamos un conjunto de casos de validación que prueban algunas de las funcionalidades principales ofrecidas por la arquitectura diseñada para la interoperabilidad segura, proporcionando información sobre su rendimiento y capacidades.Las infraestructuras críticas (IICC) modernas son vastos sistemas altamente complejos, que precisan del uso de las tecnologías de la información para gestionar, controlar y monitorizar el funcionamiento de estas infraestructuras. Debido a sus funciones esenciales, la protección y seguridad de las infraestructuras críticas y, por tanto, de sus sistemas de control, se ha convertido en una tarea prioritaria para las diversas instituciones gubernamentales y académicas a nivel mundial. La interoperabilidad de las IICC, en especial de sus sistemas de control (SSC), se convierte en una característica clave para que estos sistemas sean capaces de coordinarse y realizar tareas de control y seguridad de forma cooperativa. El objetivo de esta tesis se centra, por tanto, en proporcionar herramientas para la interoperabilidad segura de los diferentes SSC, especialmente los sistemas de control ciber-físicos (SCCF), de forma que se potencie la intercomunicación y coordinación entre ellos para crear un entorno en el que las diversas infraestructuras puedan realizar tareas de control y seguridad cooperativas, creando una plataforma de interoperabilidad segura capaz de dar servicio a diversas IICC, en un entorno de consciencia situacional (del inglés situational awareness) de alto espectro o área (wide-area). Para ello, en primer lugar, revisamos las amenazas de carácter más sofisticado que amenazan la operación de los sistemas críticos, particularmente enfocándonos en los ciberataques camuflados (del inglés stealth) que amenazan los sistemas de control de infraestructuras críticas como el smart grid. Enfocamos nuestra investigación al análisis y comprensión de este nuevo tipo de ataques que aparece contra los sistemas críticos, y a las posibles contramedidas y herramientas para mitigar los efectos de estos ataques