Polarimetric radar interferometry for improved mine detection and surface clutter rejection

A recently developed technique, polarimetric radar interferometry, is applied to tackle the problem of the detection of buried objects embedded in surface clutter. An experiment with a fully polarimetric radar in an anechoic chamber has been carried out using different frequency bands and baselines. The processed results show the ability of this technique to detect buried plastic mines and to measure their depth. This technique enables the detection of plastic mines even if their backscatter response is much lower than that of the surface clutter.

Robust beamforming for interference rejection in mobile communications

The problem of robust beamformer design for mobile communicationsapplications in the presence of moving co-channel sources isaddressed. A generalization of the optimum beamformer based on a statisticalmodel accounting for source movement is proposed. The new methodis easily implemented and is shown to offer dramatic improvements overconventional optimum beamforming for moving sources under a varietyof operating conditions.

On the design of peer punishment experiments

We discuss how technologies of peer punishment might bias the results that are observed in experiments. A crucial parameter is the “fine-to-fee” ratio, which describes by how much the punished subjects income is reduced relatively to the fee the punishing subject has to pay to inflict punishment. We show that a punishment technology commonly used in experiments embeds a variable fine-to-fee ratio and show that it confounds the empirical findings about why, whom, and how much subjects punish.

System analysis of a Peer-to-Peer Video-on-Demand architecture: Kangaroo

Architectural design and deployment of Peer-to-Peer Video-on-Demand (P2PVoD) systems which support VCR functionalities is attracting the interest of an increasing number of research groups within the scientific community; especially due to the intrinsic characteristics of such systems and the benefits that peers could provide at reducing the server load. This work focuses on the performance analysis of a P2P-VoD system considering user behaviors obtained from real traces together with other synthetic user patterns. The experiments performed show that it is feasible to achieve a performance close to the best possible. Future work will consider monitoring the physical characteristics of the network in order to improve the design of different aspects of a VoD system.

Peer-Practual: una tutoria entre iguals interprofessional als estudis de magisteri i psicopedagogia

Es presenten els resultats d’un projecte d’innovació didàctica consistent en la realització conjunta de pràctiques professionals entre estudiants de Magisteri d’educació Infantil i Educació Primària, i estudiants de Psicopedagogia. Aquests estudiants van treballar en parelles i van realitzar un conjunt d’activitats, pròpies de les seves futures funcions professionals, amb el suport del company. Concretament la pràctica va consistir en la planificació, desenvolupament i avaluació d’una unitat didàctica sobre un tema curricular. Mentre l’estudiant de Magisteri preparava els materials i activitats corresponents, la seva parella, l’estudiant de Psicopedagogia, l’assessorava en cada una de les fases d’instauració. Per afavorir aquesta dinàmica, els estudiants van comptar en diferents suports i instruments: - Els tutors de la universitat, corresponents a cadascun dels estudis implicats, - Una plataforma Moodle específicament organitzada per tal que els estudiants poguessin analitzar tot el procés conjuntament. En aquest espai podien utilitzar des de recursos per a la programació de la unitat, eines per realitzar un diari personal, un calendari d’activitats conjuntes o esquemes gràfics, fins a altres per editar vídeos gravats de les sessions de classe i per afavorir la seva comunicació. El projecte pretenia contribuir a millorar, tant algunes competències professionals relatives ambdós tipus d’estudiants, com modificar determinades concepcions i actituds entre mestres i psicopedagogs. Els resultats mostren que ambdós objectius van esser assolits amb escreix i que, a més d’aprendre determinades competències professionals, certs prejudicis i actituds sobre les dificultats i interès de treballar am altre, es van eliminar de manera contundent.

A Method and Tool to Support the Analysis and Enhance the Understanding of Peer-to-Peer Learning Experiences

In this paper we look at how a web-based social software can be used to make qualitative data analysis of online peer-to-peer learning experiences. Specifically, we propose to use Cohere, a web-based social sense-making tool, to observe, track, annotate and visualize discussion group activities in online courses. We define a specific methodology for data observation and structuring, and present results of the analysis of peer interactions conducted in discussion forum in a real case study of a P2PU course. Finally we discuss how network visualization and analysis can be used to gather a better understanding of the peer-to-peer learning experience. To do so, we provide preliminary insights on the social, dialogical and conceptual connections that have been generated within one online discussion group.

Open minded and open access: introducing NeoBiota, a new peer-reviewed journal of biological invasions

The Editorial presents the focus, scope, policies, and the inaugural issue of NeoBiota, a new open access peer-reviewed journal of biological invasions. The new journal NeoBiota is a continuation of the former NEOBIOTA publication series. The journal will deal with all aspects of invasion biology and impose no restrictions on manuscript size neither on use of color. NeoBiota implies an XML-based editorial workflow and several cutting-edge innovations in publishing and dissemination, such as semantic markup of and enhancements to published texts, data publication, and extensive cross-linking within the journal and to external sources

CompP2P-GUI : interfície gràfica del Sistema de Computació Distribuïda Peer to Peer (CompP2P)

CompP2P és una interfície gràfica implementada amb Java Swing 1.5 del Sistema de Còmput Distribuït P2P CompP2P. És una interfície gràfica polivalent, és a dir, pot ésser usada en diferents sistemes operatius (Linux, Mac0sX, Windows) i per tant ha d'ésser una aplicació multiplataforma. S'ha aconseguit millorar la gestió de tots els recursos de CompP2P mitjançant una interfície gràfica molt usable i també amb modificacions efectuades en el sistema base CompP2P on s'han afegit i/o millorat aspectes com la comunciació remota, les comandes de gestió del sistema, etc.

Organisational adaptation of multi-agent systems in a peer-to-peer scenario

Organisations in Multi-Agent Systems (MAS) have proven to be successful in regulating agent societies. Nevertheless, changes in agents' behaviour or in the dynamics of the environment may lead to a poor fulfilment of the system's purposes, and so the entire organisation needs to be adapted. In this paper we focus on endowing the organisation with adaptation capabilities, instead of expecting agents to be capable of adapting the organisation by themselves. We regard this organisational adaptation as an assisting service provided by what we call the Assistance Layer. Our generic Two Level Assisted MAS Architecture (2-LAMA) incorporates such a layer. We empirically evaluate this approach by means of an agent-based simulator we have developed for the P2P sharing network domain. This simulator implements 2-LAMA architecture and supports the comparison between different adaptation methods, as well as, with the standard BitTorrent protocol. In particular, we present two alternatives to perform norm adaptation and one method to adapt agents'relationships. The results show improved performance and demonstrate that the cost of introducing an additional layer in charge of the system's adaptation is lower than its benefits.

The tension between academic knowledge production and online peer production

Peer-reviewed

Smart antennas in software radio base stations

The application of adaptive antenna techniques to fixed-architecture base stations has been shown to offer wide-ranging benefits, including interference rejection capabilities or increased coverage and spectral efficiency.Unfortunately, the actual implementation ofthese techniques to mobile communication scenarios has traditionally been set back by two fundamental reasons. On one hand, the lack of flexibility of current transceiver architectures does not allow for the introduction of advanced add-on functionalities. On the other hand, theoften oversimplified models for the spatiotemporal characteristics of the radio communications channel generally give rise toperformance predictions that are, in practice, too optimistic. The advent of software radio architectures represents a big step toward theintroduction of advanced receive/transmitcapabilities. Thanks to their inherent flexibilityand robustness, software radio architecturesare the appropriate enabling technology for theimplementation of array processing techniques.Moreover, given the exponential progression ofcommunication standards in coexistence andtheir constant evolution, software reconfigurabilitywill probably soon become the only costefficientalternative for the transceiverupgrade. This article analyzes the requirementsfor the introduction of software radio techniquesand array processing architectures inmultistandard scenarios. It basically summarizesthe conclusions and results obtained withinthe ACTS project SUNBEAM,1 proposingalgorithms and analyzing the feasibility ofimplementation of innovative and softwarereconfigurablearray processing architectures inmultistandard settings.

Joint array combining and MLSE for single-user receivers in multipath Gaussian multiuser channels

The well-known structure of an array combiner along with a maximum likelihood sequence estimator (MLSE) receiveris the basis for the derivation of a space-time processor presentinggood properties in terms of co-channel and intersymbol interferencerejection. The use of spatial diversity at the receiver front-endtogether with a scalar MLSE implies a joint design of the spatialcombiner and the impulse response for the sequence detector. Thisis faced using the MMSE criterion under the constraint that thedesired user signal power is not cancelled, yielding an impulse responsefor the sequence detector that is matched to the channel andcombiner response. The procedure maximizes the signal-to-noiseratio at the input of the detector and exhibits excellent performancein realistic multipath channels.