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The problem of constructing functional observers for linear systems with unknown inputs is considered. Necessary and sufficient conditions for the existence of a proper observer (without differentiations) are revisited. A simple and explicit form of a functional observer is presented. It is shown that when such observer is not proper, it is still possible to use the High-Order Sliding Mode differentiator to implement it. Nevertheless, in such case, additional conditions on the system and the unknown input are required.  相似文献   
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Teacher education based on ‘reflective practice’ consists of observing, analysing and reflecting on teacher performance in order to improve professional practice. This article presents the results of an evaluation of a programme on mathematics teaching carried out using reflective practice. It was targeted at 284 teachers in various stages of the education system, using an approach that combines quantitative (surveys) and qualitative (interviews and reports) methods. While the study shows that the education programme generates high levels of satisfaction, pedagogical appropriateness and learning, its achievements in effectiveness are moderate. Although, in general, what is learned through teacher education is implemented in the classroom, it is done so in an isolated fashion, in other words, individually and without becoming a part of the culture of the school. The results show little evidence of its impact on student learning. The article offers proposals for improving the education programme, while, at the same time, analysing the usefulness of the approach and evaluation tools employed.  相似文献   
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The aim of this paper is to study the link relationships in the Nordic academic web space – comprised of 23 Finnish, 11 Danish and 28 Swedish academic web domains with the European one. Through social networks analysis we intend to detect sub-networks within the Nordic network, the position and role of the different university web domains and to understand the structural topology of this web space. Co-link analysis, with asymmetrical matrices and cosine measure, is used to identify thematic clusters. Results show that the Nordic network is a cohesive network, set up by three well-defined sub-networks and it rests on the Finnish and Swedish sub-networks. We conclude that the Danish network has less visibility than other Nordic countries. The Swedish one is the principal Nordic sub-network and the Finland network is a slightly isolated from Europe, with the exception of the University of Helsinki.  相似文献   
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In distributed and cooperative systems, the network structure is determinant to the success of the strategy adopted to solve complex tasks. Those systems are primarily governed by consensus protocols whose convergence is intrinsically dependent on the network topology. Most of the consensus algorithms deal with continuous values and perform average-based strategies to reach cohesion over the exchanged information. However, many problems demand distributed consensus over countable values, that cannot be handled by traditional protocols. In such a context, this work presents an approach based on semidefinite programming to design the optimal weights of a network adjacency matrix, in order to control the convergence of a distributed random consensus protocol for variables at the discrete-space domain, based on the voter model. As a second contribution, this work uses Markov theory and the biological inspiration of epidemics to find out a dynamical spreading model that can predict the information diffusion over this discrete consensus protocol. Also, convergence properties and equilibrium points of the proposed model are presented regarding the network topology. Finally, extensive numerical simulations evaluate the effectiveness of the proposed consensus algorithm, its spreading model, and the approach for optimal weight design.  相似文献   
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The author of this article attempts to set out the efforts that have been made in Catalonia (autonomous nationality within Spain) to regulate rationally the guidance and counseling services of fered to that part of the student population that has the greatest needs. She describes some models of services that have been created under the auspices of different institutions and analyzes their functions. Finally she draws a series of critical conclusions.University of Barcelona  相似文献   
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This paper aims to examine the influence of authors’ reputation on editorial bias in scholarly journals. By looking at eight years of editorial decisions in four computer science journals, including 7179 observations on 2913 submissions, we reconstructed author/referee-submission networks. For each submission, we looked at reviewer scores and estimated the reputation of submission authors by means of their network degree. By training a Bayesian network, we estimated the potential effect of scientist reputation on editorial decisions. Results showed that more reputed authors were less likely to be rejected by editors when they submitted papers receiving negative reviews. Although these four journals were comparable for scope and areas, we found certain journal specificities in their editorial process. Our findings suggest ways to examine the editorial process in relatively similar journals without recurring to in-depth individual data, which are rarely available from scholarly journals.  相似文献   
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This article documents public opinion research activities inMexico in the 1940s and the role played by Hungarian professorLászló Radványi, who immigrated to thatcountry at the height of World War II. Our research relies onseveral of Radványi's publications archived in differentcountries, as well as on interviews with family, acquaintances,and experts on the work of his wife, the German poet Anna Seghers.During his years in Mexico, Radványi founded the ScientificInstitute of Mexican Public Opinion, in 1941, and the InternationalJournal of Opinion and Attitude Research, in 1947—a forefatherof today's IJPOR. He was also a founding member of WAPOR. Hisearly "sample surveys" raised important methodological issuesand recorded opinion results that reflect the vibrant timesof war and policy making in a modernizing country. However,Radványi's contribution to the profession has been virtuallyforgotten. Until now, accounts about how public opinion researchbegan in Mexico either ignored Radványi's works or reducedhis ten years of survey research to a single footnote. Thisarticle is an attempt to fill this enormous omission and highlightsome of Radványi's contributions to these early stagesof survey research.  相似文献   
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Immediate and lasting effects of music or second‐language training were examined in early childhood using event‐related potentials. Event‐related potentials were recorded for French vowels and musical notes in a passive oddball paradigm in thirty‐six 4‐ to 6‐year‐old children who received either French or music training. Following training, both groups showed enhanced late discriminative negativity (LDN) in their trained condition (music group–musical notes; French group–French vowels) and reduced LDN in the untrained condition. These changes reflect improved processing of relevant (trained) sounds, and an increased capacity to suppress irrelevant (untrained) sounds. After 1 year, training‐induced brain changes persisted and new hemispheric changes appeared. Such results provide evidence for the lasting benefit of early intervention in young children.  相似文献   
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