Shout and Act: an Algorithm for Digital Objects Preservation Inspired from Rescue Robots

We adapt the Shout and Act algorithm to Digital Objects Preservation where agents explore file systems looking for digital objects to be preserved (victims). When they find something they “shout” so that agent mates can hear it. The louder the shout, the urgent or most important the finding is. Louder shouts can also refer to closeness. We perform several experiments to show that this system works very scalably, showing that heterogeneous teams of agents outperform homogeneous ones over a wide range of tasks complexity. The target at-risk documents are MS Office documents (including an RTF file) with Excel content or in Excel format. Thus, an interesting conclusion from the experiments is that fewer heterogeneous (varying skills) agents can equal the performance of many homogeneous (combined super-skilled) agents, implying significant performance increases with lower overall cost growth. Our results impact the design of Digital Objects Preservation teams: a properly designed combination of heterogeneous teams is cheaper and more scalable when confronted with uncertain maps of digital objects that need to be preserved. A cost pyramid is proposed for engineers to use for modeling the most effective agent combinations

Modeling and control of multibody system with flexible appendages

The objective of this work is to describe the design and the implementation of an experiment to study the dynamics and the active control of a slewing multi-link flexible structure. The experimental apparatus was designed to be representative of a flexible space structure such as a satellite with multiple flexible appendages. In this study we describe the design procedures, the analog and digital instrumentation, the analytical modeling together with model validation studies carried out through experimental modal testing and parametric system identification studies in the frequency domain. Preliminary results of a simple positional control where the sensor and the actuator are positioned physically at the same point is also described.

Large Scale Repository Auditing to ISO 16363

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Not Going it Alone: The US National Agenda for Digital Stewardship and Repositories

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Analyses of the usefulness of Software Defined Storage Solutions for Web-based Digital Preservation Applications

Presentation at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Induction of interleukin-10 by HIV antigens in peripheral mononuclear cells of health care workers after occupational exposure to HIV-1-positive blood

Evaluation of HIV-induced IL-2 production by peripheral blood mononuclear cells (PBMC) and HIV-specific T helper and cytotoxic T lymphocyte (CTL) responses in health care workers (HCW) occupationally exposed to HIV reveals a high rate of response to HIV among non-seroconverters. IL-10 is also known to interfere with HIV infection in vitro. To evaluate the induction of IL-10 by HIV antigens in HCW occupationally exposed to HIV, 18 HCW with percutaneous injury were enrolled in this study, 9 of them exposed to HIV-contaminated blood, and 9 exposed to HIV-negative blood. PBMC were incubated on plates coated with HIV-1 antigens, and IL-10 was measured in supernatants by ELISA. Five of nine HCW exposed to HIV-contaminated blood presented HIV-induced IL-10. Two of nine HCW exposed to HIV-negative source patients also had detectable levels of HIV-induced IL-10, one of them in the sample obtained on the day of accidental exposure. There was a relationship between the type of device involved in injury and IL-10 production. Individuals exposed to hollow needles or scalpels presented HIV-induced IL-10, whereas those exposed to solid needles and to digital puncture did not, suggesting a relationship between infectious load and IL-10. Although occupational exposure to HIV leads to a low rate of seroconversion, these individuals can develop an antigen-specific immune response characterized in our study by induction of IL-10 in PBMC in vitro.

The right to be forgotten under European Law: a Constitutional debate

Cet article met en lumière la perspective européenne sur un des plus importants défis que l’Internet et le Web 2.0 présente pour la vie privée et le droit à la protection des données. L’auteur y soulève des problématiques liées à la mémoire numérique et distingue à partir de plusieurs cas où les individus seraient intéressés de réclamer l'oubli tant dans les réseaux sociaux, les journaux officiels des gouvernements et dans les bibliothèques médiatiques numériques. Il trace l’histoire de l’identification du droit à l’oubli dont les fondements ont été définis par les agences françaises, italiennes et espagnoles de protection des données. En conclusion, il pose son regard sur un nouveau cadre européen de la protection des données comprenant le droit individuel à voir leurs données supprimées lorsqu’elles ne sont plus nécessaires à des fins légitimes.

Bidirectional communication using delay coupled chaotic directly modulated semiconductor lasers

Chaotic synchronization of two directly modulated semiconductor lasers with negative delayed optoelectronic feedback is investigated and this scheme is found to be useful for e±cient bidirectional communication between the lasers. A symmetric bidirec- tional coupling is identified as a suitable method for isochronal synchronization of such lasers. The optimum values of coupling and feedback strength that can provide maxi- mum quality of synchronization are identified. This method is successfully employed for encoding/decoding both analog and digital messages. The importance of a symmetric coupling is demonstrated by studying the variation of decoding efficiency with respect to asymmetric coupling.

Multi-user bidirectional communication using isochronal synchronisation of array of chaotic directly modulated semiconductor lasers

Isochronal synchronisation between the elements of an array of three mutually coupled directly modulated semiconductor lasers is utilized for the purpose of simultaneous bidirectional secure communication. Chaotic synchronisation is achieved by adding the coupling signal to the self feedback signal provided to each element of the array. A symmetric coupling is effective in inducing synchronisation between the elements of the array. This coupling scheme provides a direct link between every pair of elements thus making the method suitable for simultaneous bidirectional communication between them. Both analog and digital messages are successfully encrypted and decrypted simultaneously by each element of the array.

GA-based Optimization of a Fourth-order Sigma-delta Modulator for WLAN

Over-sampling sigma-delta analogue-to-digital converters (ADCs) are one of the key building blocks of state of the art wireless transceivers. In the sigma-delta modulator design the scaling coefficients determine the overall signal-to-noise ratio. Therefore, selecting the optimum value of the coefficient is very important. To this end, this paper addresses the design of a fourthorder multi-bit sigma-delta modulator for Wireless Local Area Networks (WLAN) receiver with feed-forward path and the optimum coefficients are selected using genetic algorithm (GA)- based search method. In particular, the proposed converter makes use of low-distortion swing suppression SDM architecture which is highly suitable for low oversampling ratios to attain high linearity over a wide bandwidth. The focus of this paper is the identification of the best coefficients suitable for the proposed topology as well as the optimization of a set of system parameters in order to achieve the desired signal-to-noise ratio. GA-based search engine is a stochastic search method which can find the optimum solution within the given constraints.

Digitales stochastisches Magnetfeld-Sensorarray

Digitales stochastisches Magnetfeld-Sensorarray Stefan Rohrer Im Rahmen eines mehrjährigen Forschungsprojektes, gefördert von der Deutschen Forschungsgesellschaft (DFG), wurden am Institut für Mikroelektronik (IPM) der Universität Kassel digitale Magnetfeldsensoren mit einer Breite bis zu 1 µm entwickelt. Die vorliegende Dissertation stellt ein aus diesem Forschungsprojekt entstandenes Magnetfeld-Sensorarray vor, das speziell dazu entworfen wurde, um digitale Magnetfelder schnell und auf minimaler Fläche mit einer guten räumlichen und zeitlichen Auflösung zu detektieren. Der noch in einem 1,0µm-CMOS-Prozess gefertigte Test-Chip arbeitet bis zu einer Taktfrequenz von 27 MHz bei einem Sensorabstand von 6,75 µm. Damit ist er das derzeit kleinste und schnellste digitale Magnetfeld-Sensorarray in einem Standard-CMOS-Prozess. Konvertiert auf eine 0,09µm-Technologie können Frequenzen bis 1 GHz erreicht werden bei einem Sensorabstand von unter 1 µm. In der Dissertation werden die wichtigsten Ergebnisse des Projekts detailliert beschrieben. Basis des Sensors ist eine rückgekoppelte Inverter-Anordnung. Als magnetfeldsensitives Element dient ein auf dem Hall-Effekt basierender Doppel-Drain-MAGFET, der das Verhalten der Kippschaltung beeinflusst. Aus den digitalen Ausgangsdaten kann die Stärke und die Polarität des Magnetfelds bestimmt werden. Die Gesamtanordnung bildet einen stochastischen Magnetfeld-Sensor. In der Arbeit wird ein Modell für das Kippverhalten der rückgekoppelten Inverter präsentiert. Die Rauscheinflüsse des Sensors werden analysiert und in einem stochastischen Differentialgleichungssystem modelliert. Die Lösung der stochastischen Differentialgleichung zeigt die Entwicklung der Wahrscheinlichkeitsverteilung des Ausgangssignals über die Zeit und welche Einflussfaktoren die Fehlerwahrscheinlichkeit des Sensors beeinflussen. Sie gibt Hinweise darauf, welche Parameter für das Design und Layout eines stochastischen Sensors zu einem optimalen Ergebnis führen. Die auf den theoretischen Berechnungen basierenden Schaltungen und Layout-Komponenten eines digitalen stochastischen Sensors werden in der Arbeit vorgestellt. Aufgrund der technologisch bedingten Prozesstoleranzen ist für jeden Detektor eine eigene kompensierende Kalibrierung erforderlich. Unterschiedliche Realisierungen dafür werden präsentiert und bewertet. Zur genaueren Modellierung wird ein SPICE-Modell aufgestellt und damit für das Kippverhalten des Sensors eine stochastische Differentialgleichung mit SPICE-bestimmten Koeffizienten hergeleitet. Gegenüber den Standard-Magnetfeldsensoren bietet die stochastische digitale Auswertung den Vorteil einer flexiblen Messung. Man kann wählen zwischen schnellen Messungen bei reduzierter Genauigkeit und einer hohen lokalen Auflösung oder einer hohen Genauigkeit bei der Auswertung langsam veränderlicher Magnetfelder im Bereich von unter 1 mT. Die Arbeit präsentiert die Messergebnisse des Testchips. Die gemessene Empfindlichkeit und die Fehlerwahrscheinlichkeit sowie die optimalen Arbeitspunkte und die Kennliniencharakteristik werden dargestellt. Die relative Empfindlichkeit der MAGFETs beträgt 0,0075/T. Die damit erzielbaren Fehlerwahrscheinlichkeiten werden in der Arbeit aufgelistet. Verglichen mit dem theoretischen Modell zeigt das gemessene Kippverhalten der stochastischen Sensoren eine gute Übereinstimmung. Verschiedene Messungen von analogen und digitalen Magnetfeldern bestätigen die Anwendbarkeit des Sensors für schnelle Magnetfeldmessungen bis 27 MHz auch bei kleinen Magnetfeldern unter 1 mT. Die Messungen der Sensorcharakteristik in Abhängigkeit von der Temperatur zeigen, dass die Empfindlichkeit bei sehr tiefen Temperaturen deutlich steigt aufgrund der Abnahme des Rauschens. Eine Zusammenfassung und ein ausführliches Literaturverzeichnis geben einen Überblick über den Stand der Technik.

Dynamic Injection of Scribble Features into Graphical Diagram Editors

Almost everyone sketches. People use sketches day in and day out in many different and heterogeneous fields, to share their thoughts and clarify ambiguous interpretations, for example. The media used to sketch varies from analog tools like flipcharts to digital tools like smartboards. Whereas analog tools are usually affected by insufficient editing capabilities like cut/copy/paste, digital tools greatly support these scenarios. Digital tools can be grouped into informal and formal tools. Informal tools can be understood as simple drawing environments, whereas formal tools offer sophisticated support to create, optimize and validate diagrams of a certain application domain. Most digital formal tools force users to stick to a concrete syntax and editing workflow, limiting the user’s creativity. For that reason, a lot of people first sketch their ideas using the flexibility of analog or digital informal tools. Subsequently, the sketch is "portrayed" in an appropriate digital formal tool. This work presents Scribble, a highly configurable and extensible sketching framework which allows to dynamically inject sketching features into existing graphical diagram editors, based on Eclipse GEF. This allows to combine the flexibility of informal tools with the power of formal tools without any effort. No additional code is required to augment a GEF editor with sophisticated sketching features. Scribble recognizes drawn elements as well as handwritten text and automatically generates the corresponding domain elements. A local training data library is created dynamically by incrementally learning shapes, drawn by the user. Training data can be shared with others using the WebScribble web application which has been created as part of this work.

Angiorresonancia versus angiografía por sustracción digital en el seguimiento de aneurismas intracraneales embolizados. Comparación del desempeño diagnóstico

Introducción: La DSA es el método de elección para el seguimiento de pacientes con aneurismas intracraneales embolizados; esta se puede asociar a complicaciones incapacitantes o mortales. La MRA se ha propuesto como método alternativo por menor costo y menos morbi-mortalidad, aunque su desempeño diagnóstico permanece en discusión debido al desarrollo de nuevos protocolos, resonadores más potentes y nuevas aplicaciones de la DSA. Metodología: Exploramos la literatura hasta la actualidad y comparamos el desempeño diagnóstico de la MRA con la DSA para detectar flujo residual posterior a la embolización terapéutica de aneurismas intracraneales. Realizamos una revisión sistemática de la literatura y meta-análisis basados en 34 artículos detectados en la búsqueda que incluyó las bases de datos PubMed, Scopus, ScIELO y BVS. Resultados: La TOF-MRA demostró sensibilidad de 86.8% (84.3%-89.1%) y especificidad de 91.2% (89%-93.1%); la SROC para TOF-MRA demostró un AUC de 0.95. El desempeño de la CE-MRA demostró sensibilidad de 88.1% (84.6%-91.1%) y especificidad de 89.1% (85.7%-91.9%); la SROC presentó una AUC de 0.93. El análisis estratificado por potencia del resonador encontró que la TOF-MRA tiene mejor desempeño con el resonador de 3T, aunque no es estadísticamente significativo. La concordancia interobservador con TOF-MRA y CE-MRA fue moderada a muy buena. Discusión: El desempeño diagnóstico de la MRA en el seguimiento de aneurismas intracraneales embolizados demostró ser bueno, con sensibilidad mayor a 84%, siendo ligeramente mejor con TOF-MRA, sin lograr reemplazar la DSA. Sin embargo, los resultados deben ser evaluados con precaución por la heterogeneidad de los resultados de los estudios incluidos. (Abreviaturas: DSA: Angiografía por Sustracción Digital; MRA: Angiografía por Resonancia Magnética; TOF-MRA: Angiorresonancia por Tiempo de Vuelo; CE-MRA: Angiorresonancia contrastada).

Harubèdè : uma proposta para o uso do movimento na arte sequencial digital

O tema central da presente tese por projeto é a Banda Desenhada, subdivisão da Arte Sequencial. O primeiro capítulo procura elencar as características que fazem com que a Banda Desenhada seja arte sequencial. O segundo capítulo propõe quatro tópicos que podem ser aplicados para que este tipo de Arte seja adaptável ao meio digital (principalmente para a rede mundial de computadores): formatos virtualmente impossíveis na obra impressa, som (ruídos e música), interatividade e movimento. O terceiro capítulo descreve todo o processo realizado (o método escolhido não é o único possível) para a criação e produção de um protótipo que apresenta uma dessas características: movimento.

English teachers in the digital age – a case study of policy and expert practice from England

This article is a case study of how English teachers in England have coped with the paradigm shift from print to digital literacy. It reviews a large scale national initiative that was intended to upskill all teachers, considers its weak impact and explores the author’s involvement in the evaluation of the project’s direct value to English teachers. It explores how this latter evaluation revealed how best practice in English using ICT was developing in a variable manner. It then reports on a recent small scale research project that investigated how very good teachers have adapted ICT successfully into their teaching. It focuses on how the English teachers studied in the project are developing a powerful new pedagogy situated in the life worlds of their students and suggests that this model may be of benefit to many teachers. The issues this article reports on have resonance in all English speaking countries. This article is also a personal story of the author’s close involvement with ICT and English over 20 years, and provides evidence for his conviction that digital technologies will eventually transform English teaching.