135 resultados para network representation


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This paper investigates foreign direct investment in the bankingsector. The attention has been addressed to test the importanceof OLI advantages as the determinants of the bank's decisionto invest in foreign locations. Nevertheless, since banks canexpand their activities abroad through different organizationalforms that imply different levels of foreign involvement, theissue of the form of representation has been tackled. Theresults show the importance of OLI advantages in the form ofrepresentation in multinational banking.

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The objective of this paper is to compare the performance of twopredictive radiological models, logistic regression (LR) and neural network (NN), with five different resampling methods. One hundred and sixty-seven patients with proven calvarial lesions as the only known disease were enrolled. Clinical and CT data were used for LR and NN models. Both models were developed with cross validation, leave-one-out and three different bootstrap algorithms. The final results of each model were compared with error rate and the area under receiver operating characteristic curves (Az). The neural network obtained statistically higher Az than LR with cross validation. The remaining resampling validation methods did not reveal statistically significant differences between LR and NN rules. The neural network classifier performs better than the one based on logistic regression. This advantage is well detected by three-fold cross-validation, but remains unnoticed when leave-one-out or bootstrap algorithms are used.

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A simplc formulation Io compute thc envelope correlation of anantenna divemiry system is dcrired. 11 is shown how to compute theenvelope correlation hom the S-parameter descnplian of the antennasystem. This approach has the advantage that i t does not require thecomputation nor the measurement of the radiation panem of theantenna system. It also offers the advantage of providing a clcaunderstanding ofthe effects ofmutual coupling and input match on thediversity performance of the antcnnii system.

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This work proposes novel network analysis techniques for multivariate time series.We define the network of a multivariate time series as a graph where verticesdenote the components of the process and edges denote non zero long run partialcorrelations. We then introduce a two step LASSO procedure, called NETS, toestimate high dimensional sparse Long Run Partial Correlation networks. This approachis based on a VAR approximation of the process and allows to decomposethe long run linkages into the contribution of the dynamic and contemporaneousdependence relations of the system. The large sample properties of the estimatorare analysed and we establish conditions for consistent selection and estimation ofthe non zero long run partial correlations. The methodology is illustrated with anapplication to a panel of U.S. bluechips.

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En la societat en què vivim cada vegada agafen més importància les pàgines web, ja que és una eina d’informació molt útil i ràpida de consultar. Per això, no s’entén que una activitat empresarial sigui del tipus que sigui, no tingui representació a la xarxa. No és necessari que l’activitat en qüestió hagi de vendre productes a través d’Internet, sinó que simplement aquesta representació pot ajudar a donar a conèixer l’empresa i a ampliar la cartera de clients. De la mateixa manera, els dispositius mòbils també s’estan convertint en una eina important en la societat d’avui en dia i una bona aplicació pot aportar-te un avantatge en moltes de les feines diàries de les persones. D’aquestes idees sorgeix el projecte de fer la web i l’aplicació pel centre de fisioteràpia Fisioripoll. La web serviria per tenir un lloc a la xarxa on donar-se a conèixer i poder captar nous clients, i l’aplicació funcionaria com a eina pel propi centre, seria una espècie d’agenda electrònica per saber les hores que tens reservades els pròxims dies. Per aconseguir un bon funcionament de la web, s’ha demanat que la pàgina sigui administrable en els seus continguts. És a dir, que els propis gestors del centre puguin canviar els texts, les imatges dels diferents apartats i gestionar les reserves dels clients. En canvi, l’aplicació serà només una eina de consulta i no s’hauria de gestionar res. Per tal de dur a terme aquesta web s’ha tingut en compte utilitzar eines de programació de distribució lliure com és el llenguatge PHP, la base de dades MySQL, jQuery, el framework Phonegap per tal de poder construir una web i una aplicació amb cost de programari nul.

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This paper analyses the predictive ability of quantitative precipitation forecasts (QPF) and the so-called "poor-man" rainfall probabilistic forecasts (RPF). With this aim, the full set of warnings issued by the Meteorological Service of Catalonia (SMC) for potentially-dangerous events due to severe precipitation has been analysed for the year 2008. For each of the 37 warnings, the QPFs obtained from the limited-area model MM5 have been verified against hourly precipitation data provided by the rain gauge network covering Catalonia (NE of Spain), managed by SMC. For a group of five selected case studies, a QPF comparison has been undertaken between the MM5 and COSMO-I7 limited-area models. Although MM5's predictive ability has been examined for these five cases by making use of satellite data, this paper only shows in detail the heavy precipitation event on the 9¿10 May 2008. Finally, the "poor-man" rainfall probabilistic forecasts (RPF) issued by SMC at regional scale have also been tested against hourly precipitation observations. Verification results show that for long events (>24 h) MM5 tends to overestimate total precipitation, whereas for short events (¿24 h) the model tends instead to underestimate precipitation. The analysis of the five case studies concludes that most of MM5's QPF errors are mainly triggered by very poor representation of some of its cloud microphysical species, particularly the cloud liquid water and, to a lesser degree, the water vapor. The models' performance comparison demonstrates that MM5 and COSMO-I7 are on the same level of QPF skill, at least for the intense-rainfall events dealt with in the five case studies, whilst the warnings based on RPF issued by SMC have proven fairly correct when tested against hourly observed precipitation for 6-h intervals and at a small region scale. Throughout this study, we have only dealt with (SMC-issued) warning episodes in order to analyse deterministic (MM5 and COSMO-I7) and probabilistic (SMC) rainfall forecasts; therefore we have not taken into account those episodes that might (or might not) have been missed by the official SMC warnings. Therefore, whenever we talk about "misses", it is always in relation to the deterministic LAMs' QPFs.

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Introduction. This paper studies the situation of research on Catalan literature between 1976 and 2003 by carrying out a bibliometric and social network analysis of PhD theses defended in Spain. It has a dual aim: to present interesting results for the discipline and to demonstrate the methodological efficacy of scientometric tools in the humanities, a field in which they are often neglected due to the difficulty of gathering data. Method. The analysis was performed on 151 records obtained from the TESEO database of PhD theses. The quantitative estimates include the use of the UCINET and Pajek software packages. Authority control was performed on the records. Analysis. Descriptive statistics were used to describe the sample and the distribution of responses to each question. Sex differences on key questions were analysed using the Chi-squared test. Results. The value of the figures obtained is demonstrated. The information obtained on the topic and the periods studied in the theses, and on the actors involved (doctoral students, thesis supervisors and members of defence committees), provide important insights into the mechanisms of humanities disciplines. The main research tendencies of Catalan literature are identified. It is observed that the composition of members of the thesis defence committees follows Lotka's Law. Conclusions. Bibliometric analysis and social network analysis may be especially useful in the humanities and in other fields which are lacking in scientometric data in comparison with the experimental sciences.

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A monoclonal antibody CC92 (IgM), raised against a fraction of rat liver enriched in Golgi membranes, recognizes a novel Endo H-resistant 74-kD membrane glycoprotein (gp74). The bulk of gp74 is confined to the cis-Golgi network (CGN). Outside the Golgi gp74 is found in tubulovesicular structures and ER foci. In cells incubated at 37 degrees C the majority of gp74 is segregated from the intermediate compartment (IC) marker p58. However, in cells treated with organelle perturbants such as low temperature, BFA, and [AIF4]- the patterns of the two proteins become indistinguishable. Both proteins are retained in the Golgi complex at 20 degrees C and in the IC at 15 degrees C. Incubation of cells with BFA results in relocation of gp74 to p58 positive IC elements. [AIF4]- induces the redistribution of gp74 from the Golgi to p58-positive vesicles and does not retard the translocation of gp74 to IC elements in cells treated with BFA. Disruption of microtubules by nocodazol results in the rapid disappearance of the Golgi elements stained by gp74 and redistribution of the protein into vesicle-like structures. The responses of gp74 to cell perturbants are in sharp contrast with those of cis/middle and trans-Golgi resident proteins whose location is not affected by low temperatures or [AIF4]-, are translocated to the ER upon addition of BFA, and stay in slow disintegrating Golgi elements in cells treated with nocodazol. The results suggest that gp74 is an itinerant protein that resides most of the time in the CGN and cycles through the ER/IC following the pathway used by p58.

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[cat] L’extensió de les activitats bancàries al segle XIX va ser liderat per alguns grups socials connectats amb el comerç, que van treure profit de la seva experiència i coneixement per estendre la seva influència al voltant del món del crèdit. A la historiografia espanyola, hi ha un conjunt de treballs que s’han centrat en aquesta gent, però en molts pocs casos s’ha fet una classificació que permeti detectar el conjunt de grups econòmics que han liderat el procés de modernització financera de l’Espanya de mitjans del segle XIX. El principal objectiu del treball és l’anàlisi dels grups socials que van formar el Banco de Barcelona entre 1844 i 1854. Aquesta institució va ser important per a la història financera i bancària d’Espanya per ser pionera en la seva activitat creditícia i d’emissió: a més, la seva experiència va servir com a base en la constitució d’un sistema financer modern a Espanya. En una societat com la catalana de mitjans del segle XIX, la confiança era un factor important per explicar la decisió d’invertir. L’aparició de noves companyies i les seves necessitats d’inversió van transformar el comportaments previs. Quin va ser el comportament dels inversors potencials? Va ser el grup que hi havia al voltant del banc el que va ascendir econòmicament en els anys centrals del segle XIX? La resposta és prou clara, els membres del consell d’administració del Banc de Barcelona formaven un grup apart dins dels grups que sorgeixen a l’economia catalana en el seu conjunt.

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The problem of searchability in decentralized complex networks is of great importance in computer science, economy, and sociology. We present a formalism that is able to cope simultaneously with the problem of search and the congestion effects that arise when parallel searches are performed, and we obtain expressions for the average search cost both in the presence and the absence of congestion. This formalism is used to obtain optimal network structures for a system using a local search algorithm. It is found that only two classes of networks can be optimal: starlike configurations, when the number of parallel searches is small, and homogeneous-isotropic configurations, when it is large.

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We propose a procedure for analyzing and characterizing complex networks. We apply this to the social network as constructed from email communications within a medium sized university with about 1700 employees. Email networks provide an accurate and nonintrusive description of the flow of information within human organizations. Our results reveal the self-organization of the network into a state where the distribution of community sizes is self-similar. This suggests that a universal mechanism, responsible for emergence of scaling in other self-organized complex systems, as, for instance, river networks, could also be the underlying driving force in the formation and evolution of social networks.

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A recent method used to optimize biased neural networks with low levels of activity is applied to a hierarchical model. As a consequence, the performance of the system is strongly enhanced. The steps to achieve optimization are analyzed in detail.

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A simple model of diffusion of innovations in a social network with upgrading costs is introduced. Agents are characterized by a single real variable, their technological level. According to local information, agents decide whether to upgrade their level or not, balancing their possible benefit with the upgrading cost. A critical point where technological avalanches display a power-law behavior is also found. This critical point is characterized by a macroscopic observable that turns out to optimize technological growth in the stationary state. Analytical results supporting our findings are found for the globally coupled case.