Improvement of a fully distributed decision making protocol for CRN

Este artículo presenta una propuesta de mejora del protocolo fully distributed decision making protocol for CRN con el fin de llevar a cabo la tarea de detección del espectro libre para las comunicaciones inalámbricas de una manera eficiente y segura.

Fully Distributed Cooperative Spectrum Sensing for Cognitive Radio Networks

Cognitive radio networks (CRN) sense spectrum occupancy and manage themselves to operate in unused bands without disturbing licensed users. The detection capability of a radio system can be enhanced if the sensing process is performed jointly by a group of nodes so that the effects of wireless fading and shadowing can be minimized. However, taking a collaborative approach poses new security threats to the system as nodes can report false sensing data to force a wrong decision. Providing security to the sensing process is also complex, as it usually involves introducing limitations to the CRN applications. The most common limitation is the need for a static trusted node that is able to authenticate and merge the reports of all CRN nodes. This paper overcomes this limitation by presenting a protocol that is suitable for fully distributed scenarios, where there is no static trusted node.

Hybrid turbo FEC/ARQ systems and distributed space-time coding for cooperative transmission

Cooperative transmission can be seen as a "virtual" MIMO system, where themultiple transmit antennas are in fact implemented distributed by the antennas both at the source and the relay terminal. Depending on the system design, diversity/multiplexing gainsare achievable. This design involves the definition of the type of retransmission (incrementalredundancy, repetition coding), the design of the distributed space-time codes, the errorcorrecting scheme, the operation of the relay (decode&forward or amplify&forward) and thenumber of antennas at each terminal. Proposed schemes are evaluated in different conditionsin combination with forward error correcting codes (FEC), both for linear and near-optimum(sphere decoder) receivers, for its possible implementation in downlink high speed packetservices of cellular networks. Results show the benefits of coded cooperation over directtransmission in terms of increased throughput. It is shown that multiplexing gains areobserved even if the mobile station features a single antenna, provided that cell wide reuse of the relay radio resource is possible.

Automated monitoring of medical protocols: a secure and distributed architecture

The control of the right application of medical protocols is a key issue in hospital environments. For the automated monitoring of medical protocols, we need a domain-independent language for their representation and a fully, or semi, autonomous system that understands the protocols and supervises their application. In this paper we describe a specification language and a multi-agent system architecture for monitoring medical protocols. We model medical services in hospital environments as specialized domain agents and interpret a medical protocol as a negotiation process between agents. A medical service can be involved in multiple medical protocols, and so specialized domain agents are independent of negotiation processes and autonomous system agents perform monitoring tasks. We present the detailed architecture of the system agents and of an important domain agent, the database broker agent, that is responsible of obtaining relevant information about the clinical history of patients. We also describe how we tackle the problems of privacy, integrity and authentication during the process of exchanging information between agents.

Effect of radar rainfall time resolution on the predictive capability of a distributed hydrologic model

The performance of a hydrologic model depends on the rainfall input data, both spatially and temporally. As the spatial distribution of rainfall exerts a great influence on both runoff volumes and peak flows, the use of a distributed hydrologic model can improve the results in the case of convective rainfall in a basin where the storm area is smaller than the basin area. The aim of this study was to perform a sensitivity analysis of the rainfall time resolution on the results of a distributed hydrologic model in a flash-flood prone basin. Within such a catchment, floods are produced by heavy rainfall events with a large convective component. A second objective of the current paper is the proposal of a methodology that improves the radar rainfall estimation at a higher spatial and temporal resolution. Composite radar data from a network of three C-band radars with 6-min temporal and 2 × 2 km2 spatial resolution were used to feed the RIBS distributed hydrological model. A modification of the Window Probability Matching Method (gauge-adjustment method) was applied to four cases of heavy rainfall to improve the observed rainfall sub-estimation by computing new Z/R relationships for both convective and stratiform reflectivities. An advection correction technique based on the cross-correlation between two consecutive images was introduced to obtain several time resolutions from 1 min to 30 min. The RIBS hydrologic model was calibrated using a probabilistic approach based on a multiobjective methodology for each time resolution. A sensitivity analysis of rainfall time resolution was conducted to find the resolution that best represents the hydrological basin behaviour.

Feblesa de tutories: manca de feedback i autoregulació en l'estudiant d'infermeria. Valoració de l'avaluació continuada en l'assignatura Ciències Psicosocials Aplicades a la Salut en el Grau d'Infermeria (EEES), (2009-2010)

Resum: En el nou model derivat de l"Espai Europeu d"Educació Superior (EEES), l"ensenyament aprenentatge (E-A) es centra en l"estudiant, enfront del rol més destacat del professor en l"ensenyament tradicional. El procés d"experimentació al que assistim en el nostre medi, requereix la valoració de les primeres experiències. Objectiu: L"objectiu d"aquest estudi és identificar si la metodologia utilitzada en l"assignatura Ciències Psicosocials Aplicades a la Salut, en el Grau d"Infermeria a l"Escola d" infermeria de la Universitat de Barcelona, està ben enfocada per assolir una avaluació continuada de qualitat. Metodologia: Es presenta a traves d"un estudi descriptiu. La població estudiada mitjançant un qüestionari, ha estat els estudiants dels quatre grups de primer curs, del primer any de desenvolupament del Grau d"Infermeria en el nostre Centre, passades el curs acadèmic 2009-2010, amb una mostra total de 221 alumnes. Conclusions: Els resultats permeten tres franges interpretatives: 1) qualificació de notable que fa referència a la modalitat disciplinar i experiència docent del professorat, 2) qualificació entre notable i aprovat referida a la metodologia didàctica i organitzativa, 3) qualificació d"aprovat que fa referència a les tutories.

Feblesa de tutories: manca de feedback i autoregulació en l'estudiant d'infermeria. Valoració de l'avaluació continuada en l'assignatura Ciències Psicosocials Aplicades a la Salut en el Grau d'Infermeria (EEES), (2009-2010)

Resum: En el nou model derivat de l"Espai Europeu d"Educació Superior (EEES), l"ensenyament aprenentatge (E-A) es centra en l"estudiant, enfront del rol més destacat del professor en l"ensenyament tradicional. El procés d"experimentació al que assistim en el nostre medi, requereix la valoració de les primeres experiències. Objectiu: L"objectiu d"aquest estudi és identificar si la metodologia utilitzada en l"assignatura Ciències Psicosocials Aplicades a la Salut, en el Grau d"Infermeria a l"Escola d" infermeria de la Universitat de Barcelona, està ben enfocada per assolir una avaluació continuada de qualitat. Metodologia: Es presenta a traves d"un estudi descriptiu. La població estudiada mitjançant un qüestionari, ha estat els estudiants dels quatre grups de primer curs, del primer any de desenvolupament del Grau d"Infermeria en el nostre Centre, passades el curs acadèmic 2009-2010, amb una mostra total de 221 alumnes. Conclusions: Els resultats permeten tres franges interpretatives: 1) qualificació de notable que fa referència a la modalitat disciplinar i experiència docent del professorat, 2) qualificació entre notable i aprovat referida a la metodologia didàctica i organitzativa, 3) qualificació d"aprovat que fa referència a les tutories.

Feedback i oportunitats de millora: una avaluació orientada a l"aprenentatge actiu

This paper analyzes an innovative experience of formative assessment aimed at improving the teaching of Statistics, which could be easily extrapolated to other studies. We detail the implementation of the double correction, consisting of correcting students' work twice. With the first correction, carried out by classmates according to a rubric developed by the academic, possible errors or deficiencies are discovered, and students are provided with a feedback that allows them to correct and improve their work before being graded by the teacher; whereas in the second correction of the work, once upgraded, the professor evaluates and grades the work. As a result, there is a significant improvement in the quality of students" works, and an active learning from their own mistakes. Both contents and competencies are reinforced by the experience.

Negative feedback regulation of calcineurin-dependent Prz1 transcription factor by the CaMKK-CaMK1 axis in fission yeast

Calcium signals trigger the translocation of the Prz1 transcription factor from the cytoplasm to the nucleus. The process is regulated by the calciumactivated phosphatase calcineurin, which activates Prz1 thereby maintaining active transcription during calcium signalling. When calcium signalling ceases, Prz1 is inactivated by phosphorylation and exported to the cytoplasm. In budding yeast and mammalian cells, different kinases have been reported to counter calcineurin activity and regulate nuclear export. Here, we show that the Ca2+/calmodulin-dependent kinase Cmk1 is first phosphorylated and activated by the newly identified kinase CaMKK2 homologue, Ckk2, in response to Ca2+. Then, active Cmk1 binds, phosphorylates and inactivates Prz1 transcription activity whilst at the same time cmk1 expression is enhanced by Prz1 in response to Ca2+. Furthermore, Cdc25 phosphatase is also phosphorylated by Cmk1, inducing cell cycle arrest in response to an increase in Ca2+. Moreover, cmk1 deletion shows a high tolerance to chronic exposure to Ca2+, due to the lack of cell cycle inhibition and elevated Prz1 activity. This work reveals that Cmk1 kinase activated by the newly identified Ckk2 counteracts calcineurin function by negatively regulating Prz1 activity which in turn is involved in activating cmk1 gene transcription. These results are the first insights into Cmk1 and Ckk2 function in Schizosaccharomyces pombe.

Fostering Collaborative Knowledge Building by the Effective Provision of Knowledge about the Discussion Process

Peer-reviewed

Extension and evaluation of JXTA protocols for supporting reliable P2P distributed computing

Peer-reviewed