Very Long Baseline Interferometry in Italy Wide-field VLBI imaging and astrometry and prospects for an Italian VLBI network including the Sardinia Radio Telescope

In this thesis the use of widefield imaging techniques and VLBI observations with a limited number of antennas are explored. I present techniques to efficiently and accurately image extremely large UV datasets. Very large VLBI datasets must be reduced into multiple, smaller datasets if today’s imaging algorithms are to be used to image them. I present a procedure for accurately shifting the phase centre of a visibility dataset. This procedure has been thoroughly tested and found to be almost two orders of magnitude more accurate than existing techniques. Errors have been found at the level of one part in 1.1 million. These are unlikely to be measurable except in the very largest UV datasets. Results of a four-station VLBI observation of a field containing multiple sources are presented. A 13 gigapixel image was constructed to search for sources across the entire primary beam of the array by generating over 700 smaller UV datasets. The source 1320+299A was detected and its astrometric position with respect to the calibrator J1329+3154 is presented. Various techniques for phase calibration and imaging across this field are explored including using the detected source as an in-beam calibrator and peeling of distant confusing sources from VLBI visibility datasets. A range of issues pertaining to wide-field VLBI have been explored including; parameterising the wide-field performance of VLBI arrays; estimating the sensitivity across the primary beam both for homogeneous and heterogeneous arrays; applying techniques such as mosaicing and primary beam correction to VLBI observations; quantifying the effects of time-average and bandwidth smearing; and calibration and imaging of wide-field VLBI datasets. The performance of a computer cluster at the Istituto di Radioastronomia in Bologna has been characterised with regard to its ability to correlate using the DiFX software correlator. Using existing software it was possible to characterise the network speed particularly for MPI applications. The capabilities of the DiFX software correlator, running on this cluster, were measured for a range of observation parameters and were shown to be commensurate with the generic performance parameters measured. The feasibility of an Italian VLBI array has been explored, with discussion of the infrastructure required, the performance of such an array, possible collaborations, and science which could be achieved. Results from a 22 GHz calibrator survey are also presented. 21 out of 33 sources were detected on a single baseline between two Italian antennas (Medicina to Noto). The results and discussions presented in this thesis suggest that wide-field VLBI is a technique whose time has finally come. Prospects for exciting new science are discussed in the final chapter.

Blended Learning in der Musiklehrerbildung. Erfahrungen und Perspektiven am Beispiel eines Praxisprojekts

In der Lehrerbildung zu Beginn des 21. Jahrhunderts wird einem hohen Bezug zum Berufsfeld Schule, phasenübergreifender Zusammenarbeit und lebenslangem Lernen zunehmend Bedeutung geschenkt. Mehr und mehr kommt in Veröffentlichungen und auf den Internetseiten von Lehrerbildungszentren deutscher Universitäten ein umfassendes Verständnis von Lehrerbildung zum Ausdruck, das alle Phasen der Aus- und Fortbildung von Lehrkräften einschließt: Studium, Vorbereitungsdienst („Referendariat“) und Fortbildungen für Lehrkräfte im Schuldienst. Wenn Lehrerbildung in diesem Sinne gestaltet und nicht reduziert wird auf eine Phase der Ausbildung, die der Tätigkeit im Schuldienst vorangeht, wenn neben den Qualifizierungsmaßnahmen in Studium und Vorbereitungsdienst auch Fortbildungsangebote für bereits im Beruf stehende Lehrkräfte als Selbstverständlichkeit im Rahmen eines lebenslangen Lernprozesses aufgefasst werden, eröffnet die Implementierung digitaler Medien besondere Chancen – etwa im Hinblick auf kooperatives Lernen sowie auf die Arbeit mit und den Zugriff auf Unterrichtsmaterialien. Am Beispiel eines interdisziplinär angelegten Projekts, dessen Ausgangspunkt und Zentrum das Fach Musik bildet und in dem phasenverbindendes und lebenslanges Lernen einen hohen Stellenwert einnehmen, thematisiert dieser Beitrag Möglichkeiten, Perspektiven und Herausforderungen von Blended Learning in der Lehrerbildung. Es handelt sich um einen Einblick in die Verknüpfung von Präsenz- und Online-Anteilen des Projekts und in erste Ergebnisse aus der Projektevaluation. Vorgestellt werden Teilergebnisse aus einer explorativen Studie zur Bedeutung von Kooperationen und phasenübergreifender Vernetzung, im Rahmen derer unter anderem die Akzeptanz und die Relevanz des E-Learning-Angebots thematisiert wird.

Virtual Infrastructures as a Service enabling Converged Optical Networks and Data Centres

Abstract Cloud computing service emerged as an essential component of the Enterprise {IT} infrastructure. Migration towards a full range and large-scale convergence of Cloud and network services has become the current trend for addressing requirements of the Cloud environment. Our approach takes the infrastructure as a service paradigm to build converged virtual infrastructures, which allow offering tailored performance and enable multi-tenancy over a common physical infrastructure. Thanks to virtualization, new exploitation activities of the physical infrastructures may arise for both transport network and Data Centres services. This approach makes network and Data Centres’ resources dedicated to Cloud Computing to converge on the same flexible and scalable level. The work presented here is based on the automation of the virtual infrastructure provisioning service. On top of the virtual infrastructures, a coordinated operation and control of the different resources is performed with the objective of automatically tailoring connectivity services to the Cloud service dynamics. Furthermore, in order to support elasticity of the Cloud services through the optical network, dynamic re-planning features have been provided to the virtual infrastructure service, which allows scaling up or down existing virtual infrastructures to optimize resource utilisation and dynamically adapt to users’ demands. Thus, the dynamic re-planning of the service becomes key component for the coordination of Cloud and optical network resource in an optimal way in terms of resource utilisation. The presented work is complemented with a use case of the virtual infrastructure service being adopted in a distributed Enterprise Information System, that scales up and down as a function of the application requests.

OER Development and Promotion. Outcomes of an International Research Project on the OpenCourseWare Model

In this paper, we describe the successful results of an international research project focused on the use of Web technology in the educational context. The article explains how this international project, funded by public organizations and developed over the last two academic years, focuses on the area of open educational resources (OER) and particularly the educational content of the OpenCourseWare (OCW) model. This initiative has been developed by a research group composed of researchers from three countries. The project was enabled by the Universidad Politécnica de Madrid OCW Office�s leadership of the Consortium of Latin American Universities and the distance education know-how of the Universidad Técnica Particular de Loja (UTPL, Ecuador). We give a full account of the project, methodology, main outcomes and validation. The project results have further consolidated the group, and increased the maturity of group members and networking with other groups in the area. The group is now participating in other research projects that continue the lines developed here

Temperature Sensor Placement Including Routing Overhead and Sampling Inaccuracies

Dynamic thermal management techniques require a collection of on-chip thermal sensors that imply a significant area and power overhead. Finding the optimum number of temperature monitors and their location on the chip surface to optimize accuracy is an NP-hard problem. In this work we improve the modeling of the problem by including area, power and networking constraints along with the consideration of three inaccuracy terms: spatial errors, sampling rate errors and monitor-inherent errors. The problem is solved by the simulated annealing algorithm. We apply the algorithm to a test case employing three different types of monitors to highlight the importance of the different metrics. Finally we present a case study of the Alpha 21364 processor under two different constraint scenarios.

Secure optical networks based on quantum key distribution and weakly trusted repeaters

Abstract—In this paper we explore how recent technologies can improve the security of optical networks. In particular, we study how to use quantum key distribution(QKD) in common optical network infrastructures and propose a method to overcome its distance limitations. QKD is the first technology offering information theoretic secretkey distribution that relies only on the fundamental principles of quantum physics. Point-to-point QKDdevices have reached a mature industrial state; however, these devices are severely limited in distance, since signals at the quantum level (e.g., single photons) are highly affected by the losses in the communication channel and intermediate devices. To overcome this limitation, intermediate nodes (i.e., repeaters) are used. Both quantum-regime and trusted, classical repeaters have been proposed in the QKD literature, but only the latter can be implemented in practice. As a novelty, we propose here a new QKD network model based on the use of not fully trusted intermediate nodes, referred to as weakly trusted repeaters. This approach forces the attacker to simultaneously break several paths to get access to the exchanged key, thus improving significantly the security of the network. We formalize the model using network codes and provide real scenarios that allow users to exchange secure keys over metropolitan optical networks using only passive components. Moreover, the theoretical framework allows one to extend these scenarios not only to accommodate more complex trust constraints, but also to consider robustness and resiliency constraints on the network.

Strategic knowledge serendipity and arbitrage & intellectual venture capitalists: An emerging breed of knowledge entrepreneurs; and Part II: Global and Local (GloCal) knowledge logistics for innovation and competitiveness. ACES Working Papers, August 2009

Strategic Knowledge: While entrepreneurship may occur as a natural result of personal drive, it occurs most often, most robustly and is most sustainable in an environment designed to encourage it. Potential entrepreneurs become active entrepreneurs when the conditions are most supportive of their commercial opportunities and their business thus helping channel the two key qualities they exhibit as individuals obsessed maniacs and clairvoyant oracles (Carayannis, GWU Lectures, 2000-2005) and (Carayannis et at, 2003a) towards the generation of sustainable wealth. So far, entrepreneurial scholars who turn into intellectual venture capitalists by founding knowledge-driven companies remain one of the least explored specie in the territory of entrepreneurship. GloCal: The increasing engagement of firms within global knowledge and production networks and their ability to source knowledge globally as well as locally (GloCally), for the development of innovation capacities will shape the future of UK's knowledge resources and its role in the global economy. Practices such as off-shoring R&D activities are widely adopted, creating challenging, and not very well understood, issues related to cross-country and inter-firm knowledge and technology flows. We seek to address the internationalisation and networking of research and innovation activities, including the roles and strategies of enterprises, universities, research centres, governments in a cross-country and inter-sectoral way, to assess the impact and the implications for sustaining and enhancing the competitiveness of UK firms and other British knowledge producers and users.

Global and local (GloCal) knowledge logistics for innovation and competitiveness. ACES Working Papers, August 2010

The increasing engagement of firms within global knowledge and production networks and their ability to source knowledge globally as well as locally (GloCally), for the development of innovation capacities will shape the future of UK's knowledge resources and its role in the global economy. Practices such as off-shoring R&D activities are widely adopted, creating challenging, and not very well understood, issues related to cross-country and inter-firm knowledge and technology flows. We seek to address the internationalisation and networking of research and innovation activities, including the roles and strategies of enterprises, universities, research centres, governments in a cross-country and inter-sectoral way, to assess the impact and the implications for sustaining and enhancing the competitiveness of UK firms and other British knowledge producers and users.

Impact of local library systems on the national networking environment : proceedings of the Library of Congress Network Advisory Committee Meeting, April 1-3, 1991.

Includes bibliographical references.

Emergent temporal behaviour and collaborative work

Although collaboration manifestly takes place in time, the role of time in shaping the behaviour of collaborations, and collaborative systems, is not well understood. Time is more than clock-time or the subjective experience of time; its effects on systems include differential rates of change of system elements, temporally non-linear behaviour and phenomena such as entrainment and synchronization. As a system driver, it generates emergent effects shaping systems and their behaviour. In the paper we present a systems view of time, and consider the implications of such a view through the case of collaborative development of a new university timetabling system. Teasing out the key temporal phenomena using the notion of temporal trajectories helps us understand the emergent temporal behaviour and suggests a means for improving outcomes.

International technology transfer and collaborative new product development:evidence and a case from the machine tool industry

In recent years, it has become increasingly common for companies to improve their competitiveness and find new markets by extending their operations through international new product development collaborations involving technology transfer. Technology development, cost reduction and market penetration are seen as the foci in such collaborative operations with the aim being to improve the competitive position of both partners. In this paper, the case of technology transfer through collaborative new product development in the machine tool sector is used to provide a typical example of such partnerships. The paper outlines the links between the operational aspects of collaborations and their strategic objectives. It is based on empirical data collected from the machine tool industries in the UK and China. The evidence includes longitudinal case studies and questionnaire surveys of machine tool manufacturers in both countries. The specific case of BSA Tools Ltd and its Chinese partner the Changcheng Machine Tool Works is used to provide an in-depth example of the operational development of a successful collaboration. The paper concludes that a phased coordination of commercial, technical and strategic interactions between the two partners is essential for such collaborations to work.

Enabling innovation:knowledge control, sharing and coordination boundaries in UK and German manufacturing

We investigate how boundaries in knowledge control, sharing and co-ordination influence UK and German manufacturing firms’ innovation intensity (an indicator of the volume of product change) and product life (an indicator of the pace of generational change). In general UK plants more commonly face knowledge control boundaries related to plant ownership or control, while German plants more commonly face boundaries related to knowledge sharing and knowledge co-ordination between functional groups. Our empirical results emphasise the importance of the strategic management of innovation. Knowledge control boundaries – related to external ownership, group membership and decision making autonomy – have a weak negative influence on plants’ innovation outcomes. Strategic decisions relating to multifunctional working and networking are found to be more important in overcoming knowledge sharing and co-ordination boundaries. Knowledge sharing boundaries, related to plant or company boundaries, prove most important where a plant has no in-house R&D capability. Knowledge co-ordination boundaries related to functional or multi-functional working have strong but differential effects on different innovation output measures: functional boundaries increase product life in both countries, and in Germany maintaining functional boundaries is also associated with increased innovation intensity.

Location and network effects on innovation success:evidence for UK, German and Irish manufacturing plants

Recent developments in the new economic geography and the literature on regional innovation systems have emphasised the potentially important role of networking and the characteristics of firms' local operating environment in shaping their innovative activity. Modeling UK, German and Irish plants' investments in R&D, technology transfer and networking, and their effect on the extent and success of plants' innovation activities, casts some doubt on the importance of both of these relationships. In particular, our analysis provides no support for the contention that firms or plants in the UK, Ireland or Germany with more strongly developed external links (collaborative networks or technology transfer) develop greater innovation intensity. However, although inter-firm links also have no effect on the commercial success of plants' innovation activity, intra-group links are important in terms of achieving commercial success. We also find evidence that R&D, technology transfer and networking inputs are substitutes rather than complements in the innovation process, and that there are systematic sectoral and regional influences in the efficiency with which such inputs are translated into innovation outputs. © 2001 Elsevier Science B.V.

Energy efficient architectures and techniques for green radio access networks

Energy consumption in wireless networks, and in particular in cellular mobile networks, is now of major concern in respect of their potential adverse impact upon the environment and their escalating operating energy costs. The recent phenomenal growth of data services in cellular mobile networks has exacerbated the energy consumption issue and is forcing researchers to address how to design future wireless networks that take into account energy consumption constraints. One fundamental approach to reduce energy consumption of wireless networks is to adopt new radio access architectures and radio techniques. The Mobile VCE (MVCE) Green Radio project, established in 2009, is considering such new architectural and technical approaches. This paper reports highlights the key research issues pursued in the MVCE Green Radio project.