IMT Institutional Repository: No conditions. Results ordered -Date Deposited. 2024-02-24T20:02:56ZEPrintshttp://eprints.imtlucca.it/images/logowhite.pnghttp://eprints.imtlucca.it/2018-03-09T11:34:11Z2018-03-09T11:34:11Zhttp://eprints.imtlucca.it/id/eprint/3983This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/39832018-03-09T11:34:11ZPotenzialità economica e risorsa umanaIl contributo riflette sui cambiamento in atto nel governano economico dell'azienda e pone le premesse per uno sviluppo della strategie aziendale in stretta simbiosi con il capitale cognitivo riconducibili alle risorse umaneNicola Lattanzinicola.lattanzi@imtlucca.it2016-04-05T10:39:18Z2016-04-06T12:29:21Zhttp://eprints.imtlucca.it/id/eprint/3375This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33752016-04-05T10:39:18ZResting state brain glucose metabolism is not reduced in normotensive healthy men during aging, after correction for brain atrophyStudies using positron emission tomography (PET) have reported that global and regional values for cerebral blood flow and metabolic rates for glucose (CMRglc and rCMRglc) decline with age in humans. We wished to determine if such decreases could have reflected a partial volume effect (PVE) of cerebral atrophy in the elderly, rather than “intrinsic” reductions per gram brain. We used PET to compare rCMRglc, before and after correcting for the PVE, between 13 healthy older men (aged: 55–82 years) and 11 healthy young men (aged: 22–34 years). PET was performed with Full-size image (<1 K)-fluoro-2-deoxy-d-glucose while the subjects were in the “resting” state (eyes covered and ears plugged with cotton). The PET scans were normalized to a common brain volume after superimposing them on the subjects’ tissue segmented magnetic resonance scans. Analysis showed that rCMRglc in the absence of a PVE correction was significantly less in the older group in insular, frontal, superior temporal cortical, and thalamic regions. Statistical significant differences in rCMRglc, however, were absent after the PVE correction. Thus, statistically significant age reductions in regional brain glucose metabolism, corrected for brain atrophy, are not detectable in healthy normotensive men scanned while in the resting state.Vicente IbáñezPietro Pietrinipietro.pietrini@imtlucca.itMaura L. FureyGene E. AlexanderPhilippe MilletArun L.W BokdeDiane TeichbergMark B. SchapiroBarry HorwitzStanley I. Rapoport2016-04-05T10:24:52Z2016-09-13T10:15:35Zhttp://eprints.imtlucca.it/id/eprint/3374This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33742016-04-05T10:24:52ZBeyond sensory images: Object-based representation in the human ventral pathwayWe investigated whether the topographically organized, category-related patterns of neural response in the ventral visual pathway are a representation of sensory images or a more abstract representation of object form that is not dependent on sensory modality. We used functional MRI to measure patterns of response evoked during visual and tactile recognition of faces and manmade objects in sighted subjects and during tactile recognition in blind subjects. Results showed that visual and tactile recognition evoked category-related patterns of response in a ventral extrastriate visual area in the inferior temporal gyrus that were correlated across modality for manmade objects. Blind subjects also demonstrated category-related patterns of response in this “visual” area, and in more ventral cortical regions in the fusiform gyrus, indicating that these patterns are not due to visual imagery and, furthermore, that visual experience is not necessary for category-related representations to develop in these cortices. These results demonstrate that the representation of objects in the ventral visual pathway is not simply a representation of visual images but, rather, is a representation of more abstract features of object form.Pietro Pietrinipietro.pietrini@imtlucca.itMaura L. FureyEmiliano Ricciardiemiliano.ricciardi@imtlucca.itMaria Ida GobbiniW.-H. Carolyn WuLeonardo CohenMario GuazzelliJames V. Haxby2016-04-05T09:57:58Z2016-09-13T10:17:50Zhttp://eprints.imtlucca.it/id/eprint/3372This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33722016-04-05T09:57:58ZPerception of optic and tactile flow both activate V5/MT cortical complex in the human brainV5/MT complex responds selectively to perception of optic flow (Morrone et al., Nature Neurosci , 2001). Since similarities exist between visual and tactile perception, we hypothesized that tactile flow might also rely on V5/MT response. We and others have shown recently that visual extrastriate cortical areas respond both during visual and tactile recognition of objects, indicating that these regions are organized in a supramodal fashion. In this study, we measured neural response evoked during visual and tactile perception of coherently moving dot patterns to test the hypothesis that V5/MT may be supramodally organized and may respond also to tactile stimulation.Nicola VanelloEmiliano Ricciardiemiliano.ricciardi@imtlucca.itDavide DenteNicola SgambelluriEnzo Pasquale ScilingoClaudio GentiliLorenzo SaniVincenzo PositanoMaria Filomena SantarelliMario GuazzelliJames V. HaxbyLuigi LandiniAntonio BicchiPietro Pietrinipietro.pietrini@imtlucca.it2016-04-05T09:48:25Z2016-09-13T10:17:30Zhttp://eprints.imtlucca.it/id/eprint/3371This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33712016-04-05T09:48:25ZA simulator for multilevel analysis of functional magnetic resonance dataNicola VanelloVincenzo PositanoMaria Filomena SantarelliEmiliano Ricciardiemiliano.ricciardi@imtlucca.itPietro Pietrinipietro.pietrini@imtlucca.itLuigi Landini2016-04-05T09:35:29Z2016-09-13T10:17:03Zhttp://eprints.imtlucca.it/id/eprint/3370This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33702016-04-05T09:35:29ZVerso la comprensione delle differenze di genereEmiliano Ricciardiemiliano.ricciardi@imtlucca.itClaudio GentiliN. WatsonPietro Pietrinipietro.pietrini@imtlucca.it2016-04-05T09:14:44Z2016-09-13T10:16:48Zhttp://eprints.imtlucca.it/id/eprint/3369This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33692016-04-05T09:14:44ZBrain activity associated with forgiving and unforgiving behavior in Humans as assessed with fMRIEmiliano Ricciardiemiliano.ricciardi@imtlucca.itClaudio GentiliM. RizzoNicola VanelloLorenzo SaniLuigi LandiniMario GuazzelliPietro Pietrinipietro.pietrini@imtlucca.it2016-04-05T08:50:04Z2016-09-13T10:15:19Zhttp://eprints.imtlucca.it/id/eprint/3368This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33682016-04-05T08:50:04ZA compatibility test for tactile displays designed for
fMRI studiesThe purpose of this document is to provide a compatibility test for
mechatronic devices to be used within a diagnostic MR environment. In order
to design new devices that can produce tactile stimuli of different nature inside
the MRI environment, compatibility tests with several materials and mechatronic
devices are reported. Results of these experiments are analyzed in order
to evaluate artefacts caused by the presence and actuation of the devices.Valentina HartwigNicola VanelloRoger GassertDominique ChapuisMaria Filomena SantarelliVincenzo PositanoEmiliano Ricciardiemiliano.ricciardi@imtlucca.itPietro Pietrinipietro.pietrini@imtlucca.itLuigi LandiniAntonio Bicchi2016-04-05T08:38:11Z2016-09-13T10:16:36Zhttp://eprints.imtlucca.it/id/eprint/3367This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33672016-04-05T08:38:11ZTactile processing of different object categories involves extrastriate visual cortical areas in the human brainFunctional magnetic resonance imaging (fMRI) studies demonstrated
that tactile discrimination evokes patterns of neural response in the extrastriate
ventral temporal cortical areas similar to those induced by the visual percept of
the same category of objects. These findings strongly indicate that object
representation in the ventral visual pathway is not simply a representation of
visual images but quite a representation of more abstract features of object
form.Emiliano Ricciardiemiliano.ricciardi@imtlucca.itMaura L. FureyMaria Ida GobbiniMario GuazzelliJames V. HaxbyPietro Pietrinipietro.pietrini@imtlucca.it2016-04-04T10:18:59Z2016-09-13T10:17:16Zhttp://eprints.imtlucca.it/id/eprint/3357This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33572016-04-04T10:18:59ZPerception of visual and tactile flow activates common cortical areas in the human brainWe report results of a pilot study using functional magnetic resonance
imaging aimed at determining the neural correlates of tactile flow. We
hypothesized that brain response to tactile flow would involve the same cortical
areas (V5/MT) that respond to optic flow. Our results showed that V5/MT cortex
indeed is activated by tactile flow perception. These findings are consistent
with a supramodal organization of brain regions involved in optic and tactile
flow processingEmiliano Ricciardiemiliano.ricciardi@imtlucca.itNicola VanelloDavide DenteNicola SgambelluriEnzo Pasquale ScilingoClaudio GentiliLorenzo SaniVincenzo PositanoMaria Filomena SantarelliMario GuazzelliJames V. HaxbyLuigi LandiniAntonio BicchiPietro Pietrinipietro.pietrini@imtlucca.it2016-04-04T10:06:27Z2016-04-04T10:06:27Zhttp://eprints.imtlucca.it/id/eprint/3356This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33562016-04-04T10:06:27ZThe functional exploration of the brain as a tool to understand the human mindPietro Pietrinipietro.pietrini@imtlucca.it2016-04-04T09:56:50Z2016-09-13T10:16:09Zhttp://eprints.imtlucca.it/id/eprint/3355This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33552016-04-04T09:56:50ZHow the brain responds to hurtful events: neural activity elicited by aggressive versus forgiving behavior in humansPietro Pietrinipietro.pietrini@imtlucca.itEmiliano Ricciardiemiliano.ricciardi@imtlucca.itClaudio GentiliNicola VanelloLorenzo SaniMario Guazzelli2016-04-04T09:49:45Z2016-09-13T10:16:22Zhttp://eprints.imtlucca.it/id/eprint/3354This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33542016-04-04T09:49:45ZSupramodal, topographic and category-related organization in the ventral visual pathwayEmiliano Ricciardiemiliano.ricciardi@imtlucca.itMaura L. FureyMaria Ida GobbiniMario GuazzelliJames V. HaxbyPietro Pietrinipietro.pietrini@imtlucca.it2016-04-04T09:39:12Z2016-09-13T10:15:56Zhttp://eprints.imtlucca.it/id/eprint/3353This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/33532016-04-04T09:39:12ZCholinergic enhancement during working memory improves information processing in the human brain: effects of age and task difficultyPietro Pietrinipietro.pietrini@imtlucca.itEmiliano Ricciardiemiliano.ricciardi@imtlucca.itMaura L. Furey2016-01-13T13:03:45Z2016-09-14T10:21:18Zhttp://eprints.imtlucca.it/id/eprint/2993This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/29932016-01-13T13:03:45ZValorizzazione e fruizione dei beni culturaliLorenzo Casinilorenzo.casini@imtlucca.it2016-01-13T12:57:53Z2016-09-14T10:21:18Zhttp://eprints.imtlucca.it/id/eprint/2992This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/29922016-01-13T12:57:53ZL'Agenzia del farmaco: ufficio-agenzia o agenzia-ente pubblico?Lorenzo Casinilorenzo.casini@imtlucca.it2014-10-07T13:16:48Z2015-04-08T10:37:32Zhttp://eprints.imtlucca.it/id/eprint/2290This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/22902014-10-07T13:16:48ZThe spatial logic model checker user's manual: version 0.9Hugo Torres Vieirahugo.torresvieira@imtlucca.itLuis Caires2014-07-08T14:21:55Z2014-07-08T14:21:55Zhttp://eprints.imtlucca.it/id/eprint/2253This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/22532014-07-08T14:21:55ZStability of hybrid model predictive controlIn this paper we investigate the stability of hybrid systems in closed-loop with Model Predictive
Controllers (MPC) and we derive a priori sufficient conditions for Lyapunov asymptotic stability and
exponential stability. A general theory is presented which proves that Lyapunov stability is achieved for
both terminal cost and constraint set and terminal equality constraint hybrid MPC, even though the
considered Lyapunov function and the system dynamics may be discontinuous. For particular choices
of MPC criteria and constrained Piecewise Affine (PWA) systems as the prediction models we develop
novel algorithms for computing the terminal cost and the terminal constraint set. For a quadratic MPC
cost, the stabilization conditions translate into a linear matrix inequality while, for an 1-norm based
MPC cost, they are obtained as 1-norm inequalities. It is shown that by using 1-norms, the terminal
constraint set is automatically obtained as a polyhedron or a finite union of polyhedra by taking a
sublevel set of the calculated terminal cost function. New algorithms are developed for calculating
polyhedral or piecewise polyhedral positively invariant sets for PWA systems. In this manner, the on-line
optimization problem leads to a mixed integer quadratic programming problem or to a mixed integer
linear programming problem, which can be solved by standard optimization tools. Several examples
illustrate the effectiveness of the developed methodology.Mircea LazarW.P.M.H. HeemelsSiep WeilandAlberto Bemporadalberto.bemporad@imtlucca.it2013-12-04T10:48:20Z2013-12-04T10:48:20Zhttp://eprints.imtlucca.it/id/eprint/2032This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/20322013-12-04T10:48:20ZKarl Popper's anti-foundationalist conception of rationalityStefano Gatteistefano.gattei@imtlucca.it2013-11-22T09:45:24Z2014-10-09T09:20:26Zhttp://eprints.imtlucca.it/id/eprint/1926This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/19262013-11-22T09:45:24ZOn the reliability of microscopical contact models In this paper a comparison among several micromechanical contact models is presented. The aim of the research is to provide a degree of confidence about the differences between the predictions of the contact behavior provided by the models. For this purpose some ideal microscopically rough surfaces with self-affine topography have been generated by means of a numerical algorithm. From such surfaces all the parameters needed to characterize them from the statistical viewpoint have been extracted. The predictions provided by the models with increasing normal load for the evolution of the real contact area, the number of contact points and other useful parameters have been outlined with diagrams, clearly showing the existing differences. Giorgio ZavariseMauro Borri BrunettoMarco Paggimarco.paggi@imtlucca.it2013-11-22T09:38:18Z2014-10-09T09:20:26Zhttp://eprints.imtlucca.it/id/eprint/1925This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/19252013-11-22T09:38:18ZInterface crack propagation in concrete composites: symptotic analysis of stress-singularitiesAlberto CarpinteriMarco Paggimarco.paggi@imtlucca.it2013-11-21T15:17:43Z2014-10-09T09:20:26Zhttp://eprints.imtlucca.it/id/eprint/1924This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/19242013-11-21T15:17:43ZInfluence of interface bonding strength on brittle crack propagation in bi-material structural componentsThe influence of the interface bonding strength on brittle crack propagation in bi-material structures is investigated. In this study a crack is set at the vertex of the interface between two joined dissimilar materials. Competition between several possible crack trajectories is endeavoured, paying special attention to the effect of thermo-elastic and residual stresses on crack propagation.Alberto CarpinteriMarco Paggimarco.paggi@imtlucca.it2013-11-21T15:03:00Z2014-10-09T09:20:26Zhttp://eprints.imtlucca.it/id/eprint/1923This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/19232013-11-21T15:03:00ZInfluence of the intermediate material on the singular stress field in tri-material junctionsAccording to the mathematical formalism of the eigenfunction expansion method, the problem of stress-singularities arising from multi-material junctions is addressed. The wedges are composed of isotropic homogeneous materials and are in a condition of plane stress or strain. The order of the stress-singularity is provided for tri-material junctions, paying special attention to the role played by Mode-I and Mode-II deformation. The effect of cracks inside either the softer or the stiffer material is also investigated. Numerical results can be profitably used for establishing optimum material configurations.Alberto CarpinteriMarco Paggimarco.paggi@imtlucca.it2013-11-21T14:56:44Z2014-10-09T09:20:26Zhttp://eprints.imtlucca.it/id/eprint/1922This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/19222013-11-21T14:56:44ZTheoretical and numerical investigation on internal instability phenomena in composite materialsInstability phenomena occurring in the microstructure of composite materials are investigated. To this aim, a
complete description of the mechanical behavior of bi-material interfaces in composite materials requires the
definition of both a cohesive law involving damage for the debonding stage, and a contact model during the
closure of the interface. Both formulations are herein presented and implemented in the FE code FEAP.
Numerical examples showing the transition from a snap-back instability to a stable mechanical response are
presented.Alberto CarpinteriMarco Paggimarco.paggi@imtlucca.it2012-10-12T13:07:55Z2013-06-11T12:08:59Zhttp://eprints.imtlucca.it/id/eprint/1397This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/13972012-10-12T13:07:55ZMilitanti e vita di base del Pci: il partito delle sezioni 1945-1989At the centre of this essay about the Turin’s federation of the Italian Communist Party is the life of the base of the party from the particular point of view of the sections, that are the basic organ of the organization. Since 1945 these organs lived a big expansion, that increased exceptionally since 1956, starting from a new conception of the organization of the party, that is finalized to develop a stronger activity into the people, as it is normal for a Popular Party in a phase of de-ideologisation. It is significant that in a traditional communist city as Turin some section had a very intensive power, especially during the 70s and the big growth of the party, so intensive that can exercise a pressure on the government of the city and on the federal ruling group of the party, originating an internal dualism into the party. Fiammetta Balestraccifiammetta.balestracci@imtlucca.it2012-10-12T09:58:57Z2013-06-11T11:55:48Zhttp://eprints.imtlucca.it/id/eprint/1388This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/13882012-10-12T09:58:57ZLa Prussia tra reazione e rivoluzione, 1918-1920: la riorganizzazione degli interessi agricoli tra esperienze consiliari e modelli corporativi The book is the publication of the PhD dissertation of the Author and focuses on the social, political and economic reaction of the Prussian – German – countryside to the World War One and the Councils Revolution that was at the origin of the birth of the Weimar Republic. In the chaotic time of the Post War Period the German Councils became in the countryside a instrument in the hands of different political spokesman of the rural areas for implementing different and radical alternative plans with the aim of a new functioning of the rural society: in the hands of the agrarian associations and of the Prussian landholders was an instrument of restoration in the direction of a new corporatisation of the agricultural interests; in the hands of the revolutionary urban and military councils was an activity field for trying to democratize the structure of the society and the economy of the lands, a possibility that went punctually missed. The dissertation can be considered a typical example of Social History, inspired and influenced by the historiographical theories of the New Social History of the School of Bielefeld. Fiammetta Balestraccifiammetta.balestracci@imtlucca.it2012-07-04T08:57:29Z2012-07-04T08:57:29Zhttp://eprints.imtlucca.it/id/eprint/1311This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/13112012-07-04T08:57:29ZEffect of dielectric polarization on the properties of charged point defects in insulating crystals: the nitrogen vacancy in AlNLarge unit cell calculations of the properties of charged point defects in insulators largely neglect dielectric polarization of the crystal, because the periodically repeated cells are so small. Embedded quantum cluster calculations with shell-model crystals, representing a single defect in a large crystal, are able to represent the polarization more realistically. For such embedded quantum clusters, we evaluate the optical excitation energy for the nitrogen vacancy in charge state (+3): vN3+ in AlN. This is done with and without dielectric polarization of the embedding crystal. A discrepancy of a few per cent is found, when both ground and excited state orbitals are well-localized within the vacancy. We show that the discrepancy rises rapidly as the excited state becomes more diffuse. We conclude that an embedded cluster approach will be required for transitions that involve even somewhat diffuse states. The investigation is based on a new model for AlN that shows promise for quantitative accuracy.John M VailDaniel SchindelA. YangOrion Pennerorion.penner@imtlucca.itRavi PandeyHuitian JiangMiguel Álvarez BlancoAurora CostalesQing Chun QiuY. Xu2012-02-27T10:57:19Z2012-02-27T10:57:19Zhttp://eprints.imtlucca.it/id/eprint/1191This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11912012-02-27T10:57:19ZThe mathematics of networks: the structure of social and biological systemsNetwork organization is just about universal in the real worldGuido Caldarelliguido.caldarelli@imtlucca.it2012-02-15T16:12:41Z2013-11-21T09:02:22Zhttp://eprints.imtlucca.it/id/eprint/1128This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11282012-02-15T16:12:41ZWidespread occurrence of the inverse square distribution in social sciences and taxonomyThe widespread occurrence of an inverse square relation in the hierarchical distribution of subcommunities within communities (or subspecies within species) has been recently invoked as a signature of hierarchical self-organization within social and ecological systems. Here we show that, whether such systems are self-organized or not, this behavior is the consequence of the treelike classification method. Different treelike classifications (both of real and truly random systems) display a similar statistical behavior when considering the sizes of their sub-branches.Guido Caldarelliguido.caldarelli@imtlucca.itCécile Caretta CartozoPaolo De Los RiosVito D. P. Servedio2012-02-15T16:02:44Z2012-02-15T16:02:44Zhttp://eprints.imtlucca.it/id/eprint/1127This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11272012-02-15T16:02:44ZStructure of cycles and local ordering in complex networksWe study the properties of quantities aimed at the characterization of grid-like ordering in complex networks. These quantities are based on the global and local behavior of cycles of order four, which are the minimal structures able to identify rectangular clustering. The analysis of data from real networks reveals the ubiquitous presence of a statistically high level of grid-like ordering that is non-trivially correlated with the local degree properties. These observations provide new insights on the hierarchical structure of complex networks.Guido Caldarelliguido.caldarelli@imtlucca.itRomualdo Pastor-SatorrasAlessandro Vespignani2012-02-15T15:54:46Z2012-02-15T15:54:46Zhttp://eprints.imtlucca.it/id/eprint/1126This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11262012-02-15T15:54:46ZPreface on "Applications of Networks"Guido Caldarelliguido.caldarelli@imtlucca.itAyşe ErzanAlessandro Vespignani2012-02-15T15:49:49Z2012-02-15T15:49:49Zhttp://eprints.imtlucca.it/id/eprint/1125This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11252012-02-15T15:49:49ZVirtual Round Table on ten leading questions for network researchThe following discussion is an edited summary of the public debate started during the conference "Growing Networks and Graphs in Statistical Physics, Finance, Biology and Social Systems" held in Rome in September 2003. Drafts documents were circulated electronically among experts in the field and additions and follow-up to the original discussion have been included. Among the scientists participating to the discussion L.A.N. Amaral, A. Barrat, A.L. Barabasi, G. Caldarelli, P. De Los Rios, A. Erzan, B. Kahng, R. Mantegna, J.F.F. Mendes, R. Pastor-Satorras, A. Vespignani are acknowledged for their contributions and editing. Luis A. N. AmaralAlain BarratGuido Caldarelliguido.caldarelli@imtlucca.itAlbert-László BarabásiPaolo De Los RiosAyşe ErzanByungnam KahngRosario Nunzio MantegnaJosè F. F. MendesRomualdo Pastor-SatorrasAlessandro Vespignani2012-02-15T15:33:23Z2012-02-15T15:33:23Zhttp://eprints.imtlucca.it/id/eprint/1124This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11242012-02-15T15:33:23ZNetworks of equities in financial marketsWe review the recent approach of correlation based networks of financial equities. We investigate portfolio of stocks at different time horizons, financial indices and volatility time series and we show that meaningful economic information can be extracted from noise dressed correlation matrices. We show that the method can be used to falsify widespread market models by directly comparing the topological properties of networks of real and artificial markets.Giovanni BonannoGuido Caldarelliguido.caldarelli@imtlucca.itFabrizio LilloSalvatore MiccichèNicolas VandewalleRosario Nunzio Mantegna2012-02-15T14:23:12Z2012-02-15T14:23:12Zhttp://eprints.imtlucca.it/id/eprint/1123This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11232012-02-15T14:23:12ZStatistical features of drainage basins in mars channel networks: can one guess from the landscape the past presence of water?Erosion by flowing water is one of the major forces shaping the surface of Earth. Studies in the last decade have shown, in particular, that the drainage region of rivers, where water is collected, exhibits scale invariant features characterized by exponents that are the same for rivers around the world. Here we show that from the data obtained by the MOLA altimeter of the Mars Global Surveyor one can perform the same analysis for mountain sides on Mars. We then show that in some regions fluid erosion might have played a role in the present martian landscape.Guido Caldarelliguido.caldarelli@imtlucca.itPaolo De Los RiosMarco MontuoriVito D. P. Servedio2012-02-14T14:36:31Z2013-11-21T09:03:40Zhttp://eprints.imtlucca.it/id/eprint/1121This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11212012-02-14T14:36:31ZPreferential exchange: strengthening connections in complex networksMany social, technological, and biological interactions involve network relationships whose outcome intimately depends on the structure of the network and on the strengths of the connections. Yet, although much information is now available concerning the structure of many networks, the strengths are more difficult to measure. Here we show that, for one particular social network, notably the e-mail network, a suitable measure of the strength of the connections can be available. We also propose a simple mechanism, based on positive feedback and reciprocity, that can explain the observed behavior and that hints toward specific dynamics of formation and reinforcement of network connections. Network data from contexts different from social sciences indicate that power-law, and generally broad, distributions of the connection strength are ubiquitous, and the proposed mechanism has a wide range of applicability.Guido Caldarelliguido.caldarelli@imtlucca.itFabrizio CoccettiPaolo De Los Rios2012-02-14T14:31:41Z2013-11-20T14:32:59Zhttp://eprints.imtlucca.it/id/eprint/1120This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11202012-02-14T14:31:41ZAssortative model for social networksIn this Brief Report we present a version of a network growth model, generalized in order to describe the behavior of social networks. The case of study considered is the preprint archive at cul.arxiv.org. Each node corresponds to a scientist, and a link is present whenever two authors wrote a paper together. This graph is a nice example of degree-assortative network, that is, to say a network where sites with similar degree are connected to each other. The model presented is one of the few able to reproduce such behavior, giving some insight on the microscopic dynamics at the basis of the graph structure.Michele CatanzaroGuido Caldarelliguido.caldarelli@imtlucca.itLuciano Pietronero2012-02-14T14:21:09Z2013-11-20T14:58:49Zhttp://eprints.imtlucca.it/id/eprint/1119This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11192012-02-14T14:21:09ZVertex intrinsic fitness: How to produce arbitrary scale-free networksWe study a recent model of random networks based on the presence of an intrinsic character of the vertices called fitness. The vertex fitnesses are drawn from a given probability distribution density. The edges between pairs of vertices are drawn according to a linking probability function depending on the fitnesses of the two vertices involved. We study here different choices for the probability distribution densities and the linking functions. We find that, irrespective of the particular choices, the generation of scale-free networks is straightforward. We then derive the general conditions under which scale-free behavior appears. This model could then represent a possible explanation for the ubiquity and robustness of such structures.Vito D. P. ServedioGuido Caldarelliguido.caldarelli@imtlucca.itPaolo Buttà2012-02-14T13:52:35Z2018-03-08T17:08:11Zhttp://eprints.imtlucca.it/id/eprint/1118This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11182012-02-14T13:52:35ZEmergence of complexity in financial networks We present here a brief summary of the various possible applications of network theory in the field of finance. Since we want to characterize different systems by means of simple and universal features, graph theory could represent a rather powerful methodology. In the following we report our activity in three different subfields, namely the board and director networks, the networks formed by prices correlations and the stock ownership networks. In most of the cases these three kind of networks display scale-free properties making them interesting in their own. Nevertheless, we want to stress here that the main utility of this methodology is to provide new measures of the real data sets in order to validate the different models.Guido Caldarelliguido.caldarelli@imtlucca.itStefano BattistonDiego Garlaschellidiego.garlaschelli@imtlucca.itMichele Catanzaro2012-02-14T13:25:27Z2012-02-14T13:25:27Zhttp://eprints.imtlucca.it/id/eprint/1117This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11172012-02-14T13:25:27ZThe corporate boards networksIn this work we apply network theory to detect in a quantitative fashion some of the characters of the system composed by companies and their boards of directors. Modelling this as a bipartite graph, we can derive two networks (one for the companies and one for the directors) and apply to them the standard graph analysis instruments. The emerging picture shows an environment where the exchange of information and mutual influences, conveyed by interlocks between boards, is predominant. Such a result should be taken into account when modelling this system.Guido Caldarelliguido.caldarelli@imtlucca.itMichele Catanzaro2012-02-14T13:19:55Z2012-02-14T13:19:55Zhttp://eprints.imtlucca.it/id/eprint/1116This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11162012-02-14T13:19:55ZSocial network growth with assortative mixingNetworks representing social systems display specific features that put them apart from biological and technological ones. In particular, the number of links attached to a node is positively correlated to that of its nearest neighbours. We develop a model that reproduces this feature, starting from microscopical mechanisms of growth. The statistical properties arising from the simulations are in good agreement with those of the real-world social networks of scientists co-authoring papers in condensed matter physics. Moreover, the model highlights the determinant role of correlations in shaping the network's topology.Michele CatanzaroGuido Caldarelliguido.caldarelli@imtlucca.itLuciano Pietronero2012-02-13T14:15:03Z2012-02-13T14:15:03Zhttp://eprints.imtlucca.it/id/eprint/1113This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/11132012-02-13T14:15:03ZCommunities Detection in Large NetworksWe develop an algorithm to detect community structure in complex networks. The algorithm is based on spectral methods and takes into account weights and links orientations. Since the method detects efficiently clustered nodes in large networks even when these are not sharply partitioned, it turns to be specially suitable to the analysis of social and information networks. We test the algorithm on a large-scale data-set from a psychological experiment of word association. In this case, it proves to be successful both in clustering words, and in uncovering mental association patterns. Andrea CapocciVito D. P. ServedioGuido Caldarelliguido.caldarelli@imtlucca.itFrancesca Colaiori2011-12-06T13:27:59Z2011-12-06T13:27:59Zhttp://eprints.imtlucca.it/id/eprint/1039This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/10392011-12-06T13:27:59ZDevelopment of nonlinear quantitative structure-activity relationships using RBF networks and evolutionary computingQuantitative Structure Activity Relationships (QSARs) are mathematical models that correlate structural or property descriptions of compounds (hydrophobicity, topology, electronic properties etc.) with activities, such as chemical measurements and biological assays. In this paper we propose a modeling methodology suitable for QSAR studies which selects the proper descriptors based on evolutionary computing and finally produces Radial Basis Function (RBF) neural network models. The method is successfully applied to the benchmark Selwood data set.Panagiotis Patrinospanagiotis.patrinos@imtlucca.itAlex AlexandridisAntreas AfantitisHaralambos SarimveisOlga Igglesi-Markopoulou2011-12-06T11:56:46Z2011-12-06T13:24:35Zhttp://eprints.imtlucca.it/id/eprint/1038This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/10382011-12-06T11:56:46ZUsing the Radial Basis Function (RBF) neural network architecture to develop QSARs for the prediction of the toxicity of phenols in Tetrahymena pyriformisKalliopi MakridimaAntreas AfantitisGeorgia MelagrakiPanagiotis Patrinospanagiotis.patrinos@imtlucca.itHaralambos SarimveisOlga Igglesi-Markopoulou2011-11-22T11:25:48Z2011-12-20T12:00:25Zhttp://eprints.imtlucca.it/id/eprint/1013This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/10132011-11-22T11:25:48ZAbstraction in directed model checkingAbstraction is one of the most important issues to cope with large and infinite state spaces in model checking and to reduce the verification efforts. The abstract system is smaller than the original one and if the abstract system satisfies a correctness specification, so does the concrete one. However, abstractions may introduce a behavior violating the specification that is not present in the original system.
This paper bypasses this problem by proposing the combination of abstraction with heuristic search to improve error detection. The abstract system is explored in order to create a database that stores the exact distances from abstract states to the set of abstract error states. To check, whether or not the abstract behavior is present in the original system, effcient exploration algorithms exploit the database as a guidance.Stefan EdelkampAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-10-31T15:01:12Z2011-11-03T13:19:36Zhttp://eprints.imtlucca.it/id/eprint/988This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9882011-10-31T15:01:12ZOn the behavior of the conditional expectations in Skorohod representation theoremIn this paper we deal with the Skorohod representation of a given system of probability measures. More precisely, we give conditions for the existence of a Skorohod representation (X,(Xn)) with the following additional property: for each real number p⩾1 and each real random variable Z in Lp, the conditional expectation E[Z|Xn] converges in Lp to the conditional expectation E[Z|X]
Irene Crimaldiirene.crimaldi@imtlucca.it2011-10-18T09:29:48Z2011-10-18T09:29:48Zhttp://eprints.imtlucca.it/id/eprint/950This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9502011-10-18T09:29:48ZDocumenti per lo scultore Agostino Bergamini ed i pittori Giacinto Botti e Filippo LatiniEmanuele Pellegriniemanuele.pellegrini@imtlucca.it2011-10-18T09:24:14Z2011-10-18T09:24:14Zhttp://eprints.imtlucca.it/id/eprint/949This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9492011-10-18T09:24:14ZAlcune precisazioni sulle settecentesche descrizioni di UrbinoEmanuele Pellegriniemanuele.pellegrini@imtlucca.it2011-10-13T09:58:52Z2011-10-13T13:07:07Zhttp://eprints.imtlucca.it/id/eprint/931This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9312011-10-13T09:58:52ZIntorno a Giovan Camillo SagrestaniEmanuele Pellegriniemanuele.pellegrini@imtlucca.it2011-10-13T09:13:38Z2011-10-13T09:13:38Zhttp://eprints.imtlucca.it/id/eprint/929This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9292011-10-13T09:13:38ZIl carteggio von Schlosser-Ragghianti : qualche anticipazioneEmanuele Pellegriniemanuele.pellegrini@imtlucca.it2011-10-13T09:06:25Z2011-10-13T09:06:25Zhttp://eprints.imtlucca.it/id/eprint/928This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9282011-10-13T09:06:25ZTra inventari e testamenti : uno sguardo all'interno di palazzi e ville della Valdinievole Emanuele Pellegriniemanuele.pellegrini@imtlucca.it2011-10-12T09:24:41Z2011-10-12T09:24:41Zhttp://eprints.imtlucca.it/id/eprint/915This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/9152011-10-12T09:24:41Z(a cura di) Beni culturali: prospettive e incognite del nuovo Codice : atti del Convegno, Pisa, 6 novembre 2003Contestualmente all'entrata in vigore del Nuovo Codice dei beni culturali, il primo maggio del 2004, vengono pubblicati gli atti del primo convegno nazionale dedicato al nuovo testo legislativo, tenutosi nell'Aula magna storica dell'Università di Pisa il 6 novembre del 2003. Il volume raccoglie gli interventi della giornata di studi, nei quali, a poco più di due mesi dall'approvazione definitiva della legge, avvenuta il successivo 16 gennaio, venivano prese in esame e discusse da autorevoli e qualificati studiosi bozze avanzate, ancorché non definitive, del Codice, ma anche tematiche più ampie legate al mondo dei beni culturali, all'Università, alle Soprintendenze. I singoli contributi così come la tavola rotonda conclusiva testimoniano della vivacità del dibattito e dell'attualità dei temi affrontati. Il libro si chiude con una appendice in cui viene pubblicato per intero il testo del Nuovo Codice e una mozione redatta a conclusione dei lavori.Gerardo De SimoneEmanuele Pellegriniemanuele.pellegrini@imtlucca.it2011-09-14T14:56:22Z2014-12-02T09:53:00Zhttp://eprints.imtlucca.it/id/eprint/881This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/8812011-09-14T14:56:22ZSchema e valori, vita e immaginiMaria Luisa Catonimarialuisa.catoni@imtlucca.it2011-08-11T13:38:02Z2013-03-05T15:49:42Zhttp://eprints.imtlucca.it/id/eprint/808This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/8082011-08-11T13:38:02ZDNA-based matching of digital signalsAdleman with his pioneering work set the stage for the new field of bio-computing research (Science, vol.266, p.1021-1024, 1994). His main idea was to use actual chemistry to solve problems that are either unsolvable by conventional computers, or require an enormous amount of computation. The main focus of our research is to consider the application of molecular computing to the domain of digital signal processing (DSP). In this paper, we consider matching problems that arise in signal processing applications and are amenable to a DNA-based solution. Digital data are encoded in DNA sequences using a sophisticated codeword set that satisfies the noise tolerance constraint (NTC) that we introduce. NTC, one of the main contributions of our work, takes into account the presence of noise in digital signals by exploiting the annealing between non-perfect complementary sequences. We propose an algorithm to map binary values into DNA codewords by satisfying a number of constraints, including the NTC. Using that algorithm, we retrieved 128 codewords that enables us to use a DNA based approach to digital signal matching.Sotirios A. Tsaftarissotirios.tsaftaris@imtlucca.itAggelos K. KatsaggelosThrasyvoulos N. PappasEleftherios T. Papoutsakis2011-08-10T13:30:04Z2013-03-05T15:49:17Zhttp://eprints.imtlucca.it/id/eprint/790This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/7902011-08-10T13:30:04ZHow can DNA computing be applied to digital signal processing? Although digital signals have been used as inputs in some DNA computing applications, there has been a small research regarding the application of DNA computing principles in solving DSP problems. This article offers a first step towards filling this gap and thus strengthening the ties between biology and signal processing. By focusing the attention of the article to a specific domain, the author believes that many new exciting applications of DNA computation can be discovered. A short overview of molecular biology and tools commonly used in DNA computing is also provided for presentation purposes. This article offers the signal processing community some future directions regarding the unexplored area of research in biocomputing technology.Sotirios A. Tsaftarissotirios.tsaftaris@imtlucca.itAggelos K. KatsaggelosThrasyvoulos N. PappasEleftherios T. Papoutsakis2011-08-10T13:16:49Z2013-03-05T15:49:53Zhttp://eprints.imtlucca.it/id/eprint/788This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/7882011-08-10T13:16:49ZFast watermarking of MPEG-1/2 streams using compressed-domain perceptual embedding and a generalized correlator detectorA novel technique is proposed for watermarking of MPEG-1 and MPEG-2 compressed video streams. The proposed scheme is applied directly in the domain of MPEG-1 system streams and MPEG-2 program streams (multiplexed streams). Perceptual models are used during the embedding process in order to avoid degradation of the video quality. The watermark is detected without the use of the original video sequence. A modified correlation-based detector is introduced that applies nonlinear preprocessing before correlation. Experimental evaluation demonstrates that the proposed scheme is able to withstand several common attacks. The resulting watermarking system is very fast and therefore suitable for copyright protection of compressed video.Dimitrios SimitopoulosSotirios A. Tsaftarissotirios.tsaftaris@imtlucca.itNikolaos BoulgourisAlexia BriassouliMichael Strintzis2011-08-10T13:15:46Z2013-03-05T15:49:30Zhttp://eprints.imtlucca.it/id/eprint/789This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/7892011-08-10T13:15:46ZDNA computing from a signal processing viewpointIn this article, an analysis of Adleman's experiment and a review of DNA computing applications from a signal-processing point of view are provided. In addition, certain key parts of DNA computing are emphasized, such as the code word design, to which the application of signal processing theory and techniques can offer significant advantages. The goal of this article is to introduce to the signal processing community a new unexplored area of research.Sotirios A. Tsaftarissotirios.tsaftaris@imtlucca.itAggelos K. KatsaggelosThrasyvoulos N. PappasEleftherios T. Papoutsakis2011-08-09T13:38:06Z2013-03-05T15:50:07Zhttp://eprints.imtlucca.it/id/eprint/785This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/7852011-08-09T13:38:06ZDigital watermarking for the copyright protection of compressed videoIn this chapter, a new technique for the watermarking of MPEG-1 and MPEG-2 compressed video streams is proposed. The watermarking scheme operates directly in the domain of MPEG-1 system streams and MPEG-2 program streams (multiplexed streams). Perceptual models are used during the embedding process in order to preserve video quality. The watermark is embedded in the compressed domain and is detected without the use of the original video sequence. Experimental evaluation demonstrates that the proposed scheme is able to withstand a variety of attacks. The resulting watermarking system is very fast and reliable, and is suitable for the copyright protection of video content.Dimitrios SimitopoulosSotirios A. Tsaftarissotirios.tsaftaris@imtlucca.itNikolaos BoulgourisGeorgios TriantafyllidisMichael Strintzis2011-08-09T09:09:41Z2011-08-12T15:18:50Zhttp://eprints.imtlucca.it/id/eprint/778This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/7782011-08-09T09:09:41ZIl concetto di mercato efficiente nella teoria economicaDavide Ticchidavide.ticchi@imtlucca.itGiuseppe Travaglini2011-07-27T09:02:50Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/502This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5022011-07-27T09:02:50ZA SAT-based hybrid solver for optimal control of hybrid systemsCombinatorial optimization over continuous and integer variables was proposed recently as a useful tool for solving complex optimal control problems for linear hybrid dynamical systems formulated in discrete-time. Current approaches are based on mixed-integer linear or quadratic programming (MIP), which provides the solution after solving a sequence of relaxed standard linear (or quadratic) programs (LP, QP). An MIP formulation has the drawback of requiring conversion of the discrete/logic part of the hybrid problem into mixed-integer inequalities. Although this operation can be done automatically, most of the original discrete structure of the problem is lost during the conversion. Moreover, the efficiency of the MIP solver mainly relies upon the tightness of the continuous LP/QP relaxations. In this paper we attempt to overcome such difficulties by combining MIP and techniques for solving constraint satisfaction problems into a “hybrid” solver, taking advantage of SAT solvers for dealing efficiently with satisfiability of logic constraints. We detail how to model the hybrid dynamics so that the optimal control problem can be solved by the hybrid MIP+SAT solver, and show that the achieved performance is superior to the one achieved by commercial MIP solvers. Alberto Bemporadalberto.bemporad@imtlucca.itNicolò Giorgetti2011-07-27T09:02:31Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/563This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5632011-07-27T09:02:31ZModel predictive control - new tools for design and evaluationA new version of the model predictive control toolbox for MATLAB is described. Major improvements include more flexible modeling of plant and disturbance characteristics, and support for design and simulation involving nonlinear (Simulink) models.Alberto Bemporadalberto.bemporad@imtlucca.itN. Lawrence RickerJames Gareth Owen2011-07-27T09:02:29Z2014-01-24T14:29:28Zhttp://eprints.imtlucca.it/id/eprint/628This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6282011-07-27T09:02:29ZModel Predictive Control Toolbox™ User’s GuideAlberto Bemporadalberto.bemporad@imtlucca.itManfred MorariN. Lawrence Ricker2011-07-27T08:54:00Z2011-08-05T13:56:12Zhttp://eprints.imtlucca.it/id/eprint/562This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5622011-07-27T08:54:00ZStabilizing receding horizon control of piecewise linear systems: An LMI approachReceding horizon control has recently been used for regulating discrete-time Piecewise Affine (PWA) systems. One of the obstructions for implementation consists in guaranteeing closed-loop stability a priori. This is an issue that has only been addressed marginally in the literature. In this paper we present an extension of the terminal cost method for guaranteeing stability in receding horizon control to the class of unconstrained Piecewise Linear (PWL) systems. A linear matrix inequalities set-up is developed to calculate the terminal weight matrix and the auxiliary feedback gains that ensure stability for quadratic cost based receding horizon control. It is shown that the PWL statefeedback control law employed in the stability proof globally asymptotically stabilizes the origin of the PWL system. The additional conditions needed to extend these results to constrained PWA systems are also pointed out. The implementation of the proposed method is illustrated by an example.Mircea LazarW.P.M.H. HeemelsSiep WeilandAlberto Bemporadalberto.bemporad@imtlucca.it2011-07-27T08:53:56Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/525This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5252011-07-27T08:53:56ZSAT-based branch & bound and optimal control of hybrid dynamical systemsA classical hybrid MIP-CSP approach for solving problems having a logical part and a mixed integer programming part is presented. A Branch and Bound procedure combines an MIP and a SAT solver to determine the optimal solution of a general class of optimization problems. The procedure explores the search tree, by solving at each node a linear relaxation and a satisfiability problem, until all integer variables of the linear relaxation are set to an integer value in the optimal solution. When all integer variables are fixed the procedure switches to the SAT solver which tries to extend the solution taking into account logical constraints. If this is impossible, a ldquono-goodrdquo cut is generated and added to the linear relaxation. We show that the class of problems we consider turns out to be very useful for solving complex optimal control problems for linear hybrid dynamical systems formulated in discrete-time. We describe how to model the ldquohybridrdquo dynamics so that the optimal control problem can be solved by the hybrid MIP+SAT solver, and show that the achieved performance is superior to the one achieved by commercial MIP solvers.Alberto Bemporadalberto.bemporad@imtlucca.itNicolò Giorgetti2011-07-27T08:53:53Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/504This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5042011-07-27T08:53:53ZA greedy approach to identification of piecewise affine modelsThis paper addresses the problem of identification of piecewise affine (PWA) models. This problem involves the estimation from data of both the parameters of the affine submodels and the partition of the PWA map. The procedure that we propose for PWA identification exploits a greedy strategy for partitioning an infeasible system of linear inequalities into a minimum number of feasible subsystems: this provides an initial clustering of the datapoints. Then a refinement procedure is applied repeatedly to the estimated clusters in order to improve both the data classification and the parameter estimation. The partition of the PWA map is finally estimated by considering pairwise the clusters of regression vectors, and by finding a separating hyperplane for each of such pairs. We show that our procedure does not require to fix a priori the number of affine submodels, which is instead automatically estimated from the data. Alberto Bemporadalberto.bemporad@imtlucca.itAndrea GarulliSimone PaolettiAntonio Vicino2011-07-27T08:53:49Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/566This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5662011-07-27T08:53:49ZData classification and parameter estimation for the identification of piecewise affine modelsThis paper proposes a three-stage procedure for parametric identification of piece wise affine auto regressive exogenous (PWARX) models. The first stage simultaneously classifies the data points and estimates the number of submodels and the corresponding parameters by solving the MIN PFS problem (partition into a minimum number of feasible subsystems) for a set of linear complementary inequalities derived from input-output data. Then, a refinement procedure reduces misclassifications and improves parameter estimates. The last stage determines a polyhedral partition of the regressor set via two-class or multi-class linear separation techniques. As a main feature, the algorithm imposes that the identification error is bounded by a fixed quantity δ. Such a bound is a useful tuning parameter to trade off between quality of fit and model complexity. Ideas for efficiently addressing the MIN PFS problem, and for improving data classification are also discussed in the paper. The performance of the proposed identification procedure is demonstrated on experimental data from an electronic component placement process in a pick-and-place machine.Alberto Bemporadalberto.bemporad@imtlucca.itAndrea GarulliSimone PaolettiAntonio Vicino2011-07-27T08:53:46Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/463This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/4632011-07-27T08:53:46ZEfficient conversion of mixed logical dynamical systems into an equivalent piecewise affine formFor hybrid systems described by switched linear difference equations, linear threshold conditions, automata, and propositional logic conditions, described in mixed logical dynamical form, this note describes two algorithms for transforming such systems into an equivalent piecewise affine form, where equivalent means that for the same initial conditions and input sequences the trajectories of the system are identical. The proposed techniques exploit ideas from mixed-integer programming and multiparametric programming.
Alberto Bemporadalberto.bemporad@imtlucca.it2011-07-27T08:53:44Z2011-08-05T13:58:48Zhttp://eprints.imtlucca.it/id/eprint/469This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/4692011-07-27T08:53:44ZIdentification of piecewise affine systems via mixed-integer programmingThis paper addresses the problem of identification of hybrid dynamical systems, by focusing the attention on hinging hyperplanes and Wiener piecewise affine autoregressive exogenous models, in which the regressor space is partitioned into polyhedra with affine submodels for each polyhedron. In particular, we provide algorithms based on mixed-integer linear or quadratic programming which are guaranteed to converge to a global optimum. For the special case where the estimation data only seldom switches between the different submodels, we also suggest a way of trading off between optimality and complexity by using a change detection approach.Jacob RollAlberto Bemporadalberto.bemporad@imtlucca.itLennart Ljung2011-07-27T08:53:28Z2014-07-08T13:58:48Zhttp://eprints.imtlucca.it/id/eprint/470This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/4702011-07-27T08:53:28ZInner and outer approximation of polytopes using boxesThis paper deals with the problem of approximating a convex polytope in any finite dimension by a collection of (hyper)boxes. More exactly, given a polytope by a system of linear inequalities, we look for two collections and of boxes with non-overlapping interiors such that the union of all boxes in is contained in and the union of all boxes in contains . We propose and test several techniques to construct and aimed at getting a good balance between two contrasting objectives: minimize the volume error and minimize the total number of generated boxes. We suggest how to modify the proposed techniques in order to approximate the projection of onto a given subspace without computing the projection explicitly.Alberto Bemporadalberto.bemporad@imtlucca.itCarlo FilippiFabio Danilo Torrisi2011-07-27T08:53:26Z2011-08-05T13:58:02Zhttp://eprints.imtlucca.it/id/eprint/461This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/4612011-07-27T08:53:26ZHYSDEL - A tool for generating computational hybrid modelsThis paper presents a computational framework for modeling hybrid systems in discrete-time. We introduce the class of discrete hybrid automata (DHA) and show its relation with several other existing model paradigms: piecewise affine systems, mixed logical dynamical systems, (extended) linear complementarity systems, min-max-plus-scaling systems. We present HYSDEL (hybrid systems description language), a high-level modeling language for DHA, and a set of tools for translating DHA into any of the former hybrid models. Such a multimodeling capability of HYSDEL is particularly appealing for exploiting a large number of available analysis and synthesis techniques, each one developed for a particular class of hybrid models. An automotive example shows the modeling capabilities of HYSDEL and how the different models allow to use several computational tools.Fabio Danilo TorrisiAlberto Bemporadalberto.bemporad@imtlucca.it2011-07-27T08:53:24Z2011-08-04T07:29:08Zhttp://eprints.imtlucca.it/id/eprint/462This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/4622011-07-27T08:53:24ZAnti-windup synthesis via sampled-data piecewise affine optimal controlDiscrete-time receding horizon optimal control is employed in model-based anti-windup augmentation. The optimal control formulation enables designs that minimize the mismatch between the unconstrained closed-loop response with a given controller and the constrained closed-loop response with anti-windup augmentation. Recently developed techniques for off-line computation of the constrained linear regulator's solution, which is piecewise affine, facilitate implementation. The resulting sampled-data, anti-windup closed-loop system's properties are established and its performance is demonstrated on a simulation example.Alberto Bemporadalberto.bemporad@imtlucca.itAndrew R. TeelLuca Zaccarian2011-07-27T08:53:22Z2011-08-05T13:57:21Zhttp://eprints.imtlucca.it/id/eprint/561This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5612011-07-27T08:53:22ZRobust optimal control of linear hybrid systems: An MLD approachA methodology for synthesizing robust optimal input trajectories for constrained linear hybrid systems subject to bounded additive disturbances is presented. The computed control sequence optimizes nominal performance while robustly guarantees that safety/performance constraints are respected. Specifically, for hybrid systems representable in the piecewise affine form, robustness is achieved with an open-loop optimization strategy based on the mixed logical
dynamical modelling framework.Miguel Pedro SilvaMiguel Ayala BottoLuis PinaAlberto Bemporadalberto.bemporad@imtlucca.itJosé Sa da Costa2011-07-27T08:47:44Z2012-06-26T11:21:20Zhttp://eprints.imtlucca.it/id/eprint/451This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/4512011-07-27T08:47:44ZHybrid modelling and optimal control of a multi product batch plantThis paper addresses the problem of optimally selecting the production plan for a Multiproduct Batch Plant. The proposed approach can also be applied to a broader class of optimal control problems for systems with discrete inputs. The plant is modelled as a Discrete Hybrid Automaton (DHA) using the high level modelling language, HYbrid System DEscription Language (HYSDEL), which allows conversion of the DHA model into an Mixed Logical Dynamical (MLD) model. The solution algorithm, which takes into account a model of a hybrid system described as an MLD system, is based on reachability analysis ideas. The algorithm abstracts the behaviour of the hybrid system into a “tree of evolution”, where nodes of the tree represent reachable states of the system, and branches connect two nodes if a transition exists between the corresponding states. To each node a cost function value is associated and, based on this value, the tree exploration is driven, searching for the optimal control profile.Bostjan PotocnikAlberto Bemporadalberto.bemporad@imtlucca.itFabio Danilo TorrisiGasper MusicBorut Zupancic2011-07-27T08:47:42Z2011-08-05T13:54:34Zhttp://eprints.imtlucca.it/id/eprint/564This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5642011-07-27T08:47:42ZA dynamic programming approach for determining the explicit solution of MPC controllersRecently multi-parametric methods have been applied with success to model predictive control (MPC) schemes. In this paper we propose a novel method for linear systems to obtain the explicit description of the control law that is based on dynamic programming and exploits the structure of the MPC formulation.David Muñoz de la PeñaTeodoro AlamoAlberto Bemporadalberto.bemporad@imtlucca.itEduardo F. Camacho2011-07-27T08:47:40Z2011-08-05T13:54:55Zhttp://eprints.imtlucca.it/id/eprint/565This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5652011-07-27T08:47:40ZRobust explicit MPC based on approximate multi-parametric convex programmingMany robust model predictive control (MPC) schemes require the online solution of a convex program, which can be computationally demanding. For deterministic MPC schemes, multi-parametric programming was successfully applied to move most computations offline. In this paper we adopt a general approximate multi-parametric algorithm recently suggested for convex problems and propose to apply it to a classical robust WC scheme. This approach enables one to implement a robust MPC controller in real time for systems with polytopic uncertainty, ensuring robust constraint satisfaction and robust convergence to a given bounded set.David Muñoz de la PeñaAlberto Bemporadalberto.bemporad@imtlucca.itCarlo Filippi2011-07-27T08:47:36Z2011-08-05T13:54:10Zhttp://eprints.imtlucca.it/id/eprint/521This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5212011-07-27T08:47:36ZStabilization conditions for model predictive control of constrained PWA systemsModel predictive control (MPC) has recently been applied to several relevant classes of hybrid systems with promising results. These developments generated an increasing interest towards issues such as stability and computational problems that arise in hybrid MPC. Stability aspects have been addressed only marginally. In this paper we present an extension of the terminal cost and constraint set method for guaranteeing stability in MPC to the class of constrained piecewise affine systems. Semidefinite programming is used to calculate the employed terminal weight matrix that ensures stability for quadratic cost based MPC. A procedure for computing a robust positively invariant set for piecewise linear systems is also developed. The implementation of the proposed method is illustrated by an example.Mircea LazarW.P.M.H. HeemelsSiep WeilandAlberto Bemporadalberto.bemporad@imtlucca.it2011-07-27T08:47:33Z2014-03-05T13:44:24Zhttp://eprints.imtlucca.it/id/eprint/567This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/5672011-07-27T08:47:33ZEvent-driven optimal control of continuous Petri netsOptimally controlling a hybrid system is a challenging problem for which mainly continuous-time and discrete-time methods have been suggested. In this paper, the problem of optimal control is addressed in the framework of continuous Petri nets, a kind of hybrid systems whose state evolution is piecewise linear. The proposed approach consists of transforming the continuous Petri net into an equivalent hybrid system whose evolution is described by means of discrete-event steps. In particular, each step coincides with the occurrence of an event in the continuous Petri net. Thus, the number of steps required to know the behavior of the Petri net is minimum, while the accuracy is completely preserved. It is shown how to design a mixed integer linear programming problem in order to compute the optimal control solution of different performance criteria.Jorge JúlvezAlberto Bemporadalberto.bemporad@imtlucca.itLaura RecaldeManuel Silva2011-07-01T10:02:40Z2011-08-31T14:40:39Zhttp://eprints.imtlucca.it/id/eprint/686This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6862011-07-01T10:02:40ZMarket Structure And Drug Innovation An explosion of knowledge and a growing array of tools and technologies have transformed modern drug R&D, while its cost has risen by a sizable amount. At the same time, the unchecked increase in health care and prescription drug spending has spawned cost containment policies that are restricting the demand for drugs in all major markets. This Perspective explores the interplay between technological advances and regulatory policies and their likely impact on the dynamics of the pharmaceutical industry. Fabio Pammollif.pammolli@imtlucca.itMassimo Riccabonimassimo.riccaboni@imtlucca.it2011-06-30T14:25:51Z2011-08-31T14:40:39Zhttp://eprints.imtlucca.it/id/eprint/650This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6502011-06-30T14:25:51ZStatistical properties of business firms structure and growthWe analyze a database comprising quarterly sales of 55624 pharmaceutical products commercialized by 3939 pharmaceutical firms in the period 1992-2001. We study the probability density function (PDF) of growth in firms and product sales and find that the width of the PDF of growth decays with the sales as a power law with exponent Î² = 0.20 Â± 0.01. We also find that the average sales of products scales with the firm sales as a power law with exponent Î± = 0.57 Â± 0.02. And that the average number products of a firm scales with the firm sales as a power law with exponent Î³ = 0.42 Â± 0.02. We compare these findings with the predictions of models proposed till date on growth of business firms.Fabio Pammollif.pammolli@imtlucca.itKaushik MatiaDongfeng FuSergey V. BuldyrevMassimo Riccabonimassimo.riccaboni@imtlucca.itH. Eugene Stanley2011-06-30T14:25:42Z2011-08-31T14:40:39Zhttp://eprints.imtlucca.it/id/eprint/651This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6512011-06-30T14:25:42ZDynamic competition in pharmaceuticals:
Patent expiry, generic penetration, and industry structureThis paper investigates patterns of industrial dynamics and competition in the pharmaceutical industry, with particular reference to the consequences of patent expiry in different countries. We focus on the competition at the level of single chemical entities, distinguishing between original brands and generic products. Quarterly data, spanning from July 1987 to December 1998, on sales of pharmaceutical products in four countries (USA, UK, Germany, and France) constitute the basis of our analysis. All the products containing major molecules whose patent expiration date lies between 1986 and 1996 are included in our sample. We show how diffusion of generics is linked to the characteristics of the market and investigate how price dynamics of original products are affected by generic competition. Our empirical investigation shows that the dynamics of drug prices and the competition by generic drugs vary significantly across countries. This heterogeneity notwithstanding, a clear distinction seems to emerge. On the one hand, systems that rely on market-based competition in pharmaceuticals promote a clear distinction between firms that act as innovators and firms that act as imitators after patent expiry. Here, original products enjoy premium prices and exclusivity profits under patent protection, and face fierce price competition after patent expiry. On the other hand, in systems that rely on administered prices, penetration by generic drugs tends to be rather limited. Its descriptive and preliminary nature notwithstanding, our analysis seems to have relevant implications at different levels of generality, especially for Europe.Fabio Pammollif.pammolli@imtlucca.itLaura MagazziniMassimo Riccabonimassimo.riccaboni@imtlucca.it2011-06-30T14:25:35Z2011-08-31T14:40:39Zhttp://eprints.imtlucca.it/id/eprint/652This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6522011-06-30T14:25:35ZTechnological Competencies in Networks of InnovatorsFabio Pammollif.pammolli@imtlucca.itMassimo Riccabonimassimo.riccaboni@imtlucca.it2011-06-30T14:25:27Z2014-07-02T10:38:17Zhttp://eprints.imtlucca.it/id/eprint/654This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6542011-06-30T14:25:27ZThe nature and extent of the market for technology in biopharmaceuticalsThe biopharmaceutical industry is a typical example of the development of technological collaborations, as well as of technological competition, between larger established firms and smaller high-tech specialist firms (the so-called New Biotechnology Firms — NBFs). These two types of firms perform innovative activities at different stages, with different degree of risk, and with different probability of failure. By using a comprehensive database of 2078 drug R&D projects promoted all over the world during the 1990s, this study assesses the different performance of R&D processes conducted under different governance structures, most notably projects that are fully internalised by the companies vis-àvis projects developed in collaboration with other firms. Moreover, this study compares the different specialisation and performance of large drug companies with respect to the NBFs. Results show that the established pharmaceutical companies have comparative advantages with respect to NBFs in drug development, while there is no advantage related to scale in drug discovery. Furthermore, NBFs undertake less risky project, which are more likely to fail at earlier clinical stages.Ashish AroraAlfonso GambardellaFabio Pammollif.pammolli@imtlucca.itMassimo Riccabonimassimo.riccaboni@imtlucca.it2011-06-30T14:24:51Z2011-08-31T14:40:39Zhttp://eprints.imtlucca.it/id/eprint/661This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/6612011-06-30T14:24:51ZPharmaceuticals Analysed through the Lens of a Sectoral Innovation SystemFabio Pammollif.pammolli@imtlucca.itMaureen McKelveyLuigi Orsenigo2011-05-31T12:07:34Z2014-01-15T10:28:52Zhttp://eprints.imtlucca.it/id/eprint/318This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/3182011-05-31T12:07:34ZA Formal Basis for Reasoning on Programmable QoSThe explicit management of Quality of Service (QoS) of network connectivity, such as, e.g., working cost, transaction support, and security, is a key requirement for the development of the novel wide area network applications. In this paper, we introduce a foundational model for specification of QoS attributes at application level. The model handles QoS attributes as semantic constraints within a graphical calculus for mobility. In our approach QoS attributes are related to the programming abstractions and are exploited to select, configure and dynamically modify the underlying system oriented QoS mechanisms.Rocco De Nicolar.denicola@imtlucca.itGianLuigi FerrariUgo MontanariRosario PuglieseEmilio Tuosto2011-05-27T14:08:45Z2011-07-11T14:36:25Zhttp://eprints.imtlucca.it/id/eprint/316This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/3162011-05-27T14:08:45ZFormulae Meet Programs Over the Net: A Framework for Correct Network Aware ProgrammingA general framework for network aware programming is presented that consists of a language for programming mobile applications, a logic for specifying properties of the applications and an automatic tool for verifying such properties. The framework is based on X-KLAIM, eXtended KLAIM, an experimental programming language specifically designed to program distributed systems composed of several components interacting through multiple tuple spaces and mobile code. The proposed logic is a modal logic inspired by Hennessy-Milner logic and is interpreted over the same labelled structures used for the operational semantics of X-KLAIM. The automatic verification tool is based on a complete proof system that has been previously developed for the logic.Lorenzo BettiniRocco De Nicolar.denicola@imtlucca.itMichele Loreti2011-05-24T12:59:37Z2011-07-11T14:36:25Zhttp://eprints.imtlucca.it/id/eprint/315This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/3152011-05-24T12:59:37ZA modal logic for mobile agentsKlaim is an experimental programming language that supports a programming paradigm where both processes and data can be moved across different computing environments. The language relies on the use of explicit localities. This paper presents a temporal logic for specifying properties of Klaim programs. The logic is inspired by Hennessy-Milner Logic (HML) and the μ-calculus, but has novel features that permit dealing with state properties and impact of actions and movements over the different sites. The logic is equipped with a complete proof system that enables one to prove properties of mobile systems.Michele LoretiRocco De Nicolar.denicola@imtlucca.it2011-05-24T12:52:30Z2011-07-11T14:36:25Zhttp://eprints.imtlucca.it/id/eprint/314This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/3142011-05-24T12:52:30ZA Software Framework for Rapid Prototyping of Run-Time Systems for Mobile CalculiWe describe the architecture and the implementation of the Mikado software framework, that we call IMC (Implementing Mobile Calculi). The framework aims at providing the programmer with primitives to design and implement run-time systems for distributed process calculi. The paper describes the four main components of abstract machines for mobile calculi (node topology, naming and binding, communication protocols and mobility) that have been implemented as Java packages. The paper also contains the description of a prototype implementation of a run-time system for the Distributed Pi-Calculus relying on the presented framework. Lorenzo BettiniRocco De Nicolar.denicola@imtlucca.itDaniele FalassiMarc LacosteLuis M. B. LopesLicinio OliveiraHerve PaulinoVasco Thudichum Vasconcelos2011-05-24T09:48:51Z2011-07-11T14:36:25Zhttp://eprints.imtlucca.it/id/eprint/313This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/3132011-05-24T09:48:51ZMoMo: A Modal Logic for Reasoning About MobilityA temporal logic is proposed as a tool for specifying properties of Klaim programs. Klaim is an experimental programming language that supports a programming paradigm where both processes and data can be moved across different computing environments. The language relies on the use of explicit localities. The logic is inspired by Hennessy-Milner Logic (HML) and the μ–calculus, but has novel features that permit dealing with state properties and impact of actions and movements over the different sites. The logic is equipped with a sound and complete tableaux based proof system.
Rocco De Nicolar.denicola@imtlucca.itMichele Loreti2011-05-17T13:54:29Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/167This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1672011-05-17T13:54:29ZDirected explicit-state model checking in the validation of communication protocolsThe success of model checking is largely based on its ability to efficiently locate errors in software designs. If an error is found, a model checker produces a trail that shows how the error state can be reached, which greatly facilitates debugging. However, while current model checkers find error states efficiently, the counterexamples are often unnecessarily lengthy, which hampers error explanation. This is due to the use of naive search algorithms in the state space exploration. In this paper we present approaches to the use of heuristic search algorithms in explicit-state model checking. We present the class of A * directed search algorithms and propose heuristics together with bitstate compression techniques for the search of safety property violations. We achieve great reductions in the length of the error trails, and in some instances render problems analyzable by exploring a much smaller number of states than standard depth-first search. We then suggest an improvement of the nested depth-first search algorithm and show how it can be used together with A * to improve the search for liveness property violations. Our approach to directed explicit-state model checking has been implemented in a tool set called HSF-SPIN. We provide experimental results from the protocol validation domain using HSF-SPIN.Stefan EdelkampStefan LeueAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-05-13T12:54:53Z2011-07-11T14:34:35Zhttp://eprints.imtlucca.it/id/eprint/168This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1682011-05-13T12:54:53ZPartial-order reduction and trail improvement in directed model checkingIn this paper we present work on trail improvement and partial-order reduction in the context of directed explicit-state model checking. Directed explicit-state model checking employs directed heuristic search algorithms such as A* or best-first search to improve the error-detection capabilities of explicit-state model checking. We first present the use of directed explicit-state model checking to improve the length of already established error trails. Second, we show that partial-order reduction, which aims at reducing the size of the state space by exploiting the commutativity of concurrent transitions in asynchronous systems, can coexist well with directed explicit-state model checking. Finally, we illustrate how to mitigate the excessive length of error trails produced by partial-order reduction in explicit-state model checking. In this context we also propose a combination of heuristic search and partial-order reduction to improve the length to already provided counterexamples. Stefan EdelkampStefan LeueAlberto Lluch-Lafuentealberto.lluch@imtlucca.it2011-03-30T10:14:10Z2011-07-11T14:21:54Zhttp://eprints.imtlucca.it/id/eprint/240This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/2402011-03-30T10:14:10ZIl trasferimento di dati personali in InternetNota a Corte di Giustizia delle Comunità europee, sentenza 6 novembre 2003, causa C-101/01, Lindqvist.Andrea Giannaccaria.giannaccari@imtlucca.it2011-03-30T10:13:28Z2011-07-11T14:21:54Zhttp://eprints.imtlucca.it/id/eprint/246This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/2462011-03-30T10:13:28ZStandard e protocolli: al crocevia tra definizione e monopolizzazione del mercatoAndrea Giannaccaria.giannaccari@imtlucca.it2011-03-23T11:22:23Z2011-07-11T14:27:36Zhttp://eprints.imtlucca.it/id/eprint/210This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/2102011-03-23T11:22:23ZSu alcune differenze tra Mises e LeoniAntonio Masalaa.masala@imtlucca.it2011-03-18T14:46:41Z2014-01-24T14:29:12Zhttp://eprints.imtlucca.it/id/eprint/207This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/2072011-03-18T14:46:41ZCrisi della filosofia politica e teoria del liberalismoAntonio Masalaa.masala@imtlucca.it2011-03-10T10:29:27Z2011-07-11T14:27:36Zhttp://eprints.imtlucca.it/id/eprint/198This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1982011-03-10T10:29:27ZDiritto e Stato, un contratto tra uomini liberiAntonio Masalaa.masala@imtlucca.it2011-03-03T15:03:41Z2011-07-11T13:54:05Zhttp://eprints.imtlucca.it/id/eprint/172This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1722011-03-03T15:03:41ZRaymond Aron: Nationalism and Supranationalism in the Years Following the Second World WarLucia Bonfreschilucia.bonfreschi@imtlucca.it2011-03-03T14:47:16Z2011-07-11T13:54:05Zhttp://eprints.imtlucca.it/id/eprint/140This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1402011-03-03T14:47:16ZComplotto contro la Francia: l’antiamericanismo nella stampa gollista della IV RepubblicaLucia Bonfreschilucia.bonfreschi@imtlucca.it2011-03-01T09:55:50Z2011-07-11T14:33:43Zhttp://eprints.imtlucca.it/id/eprint/129This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/1292011-03-01T09:55:50ZD-Fusion: A Distinctive Fusion CalculusWe study the relative expressive power of Fusion and pi-calculus. Fusion is commonly regarded as a generalisation of pi-calculus. Actually, we prove that there is no uniform fully abstract embedding of pi-calculus into Fusion. This fact motivates the introduction of a new calculus, D-Fusion, with two binders, λ and ν. We show that D-Fusion is strictly more expressive than both pi-calculus and Fusion. The expressiveness gap is further clarified by the existence of a fully abstract encoding of mixed guarded choice into the choice-free fragment of D-Fusion.Michele BorealeMaria Grazia Buscemim.buscemi@imtlucca.itUgo Montanari2011-02-15T10:29:10Z2011-07-11T14:24:17Zhttp://eprints.imtlucca.it/id/eprint/67This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/672011-02-15T10:29:10ZBack to Kant's ‘Sapere aude!’Stefano Gatteistefano.gattei@imtlucca.it2011-02-15T10:28:52Z2011-07-11T14:24:17Zhttp://eprints.imtlucca.it/id/eprint/68This item is in the repository with the URL: http://eprints.imtlucca.it/id/eprint/682011-02-15T10:28:52ZKarl Popper's Philosophical BreakthroughDespite his well-known deductivism, in his early (unpublished) writings, Popper held an inductivist position. Up to 1929 epistemology entered Popper's reflections only as far as the problem was that of the justification of the scientific character of these fields of research. However, in that year, while surveying the history of non-Euclidean geometries, Popper explicitly discussed the cognitive status of geometry without referring to psycho-pedagogical aspects, thus turning from cognitive psychology to the logic and methodology of science. As a consequence of his reflections on the problematic relationship between geometrical-mathematical constructions and physical reality Popper was able to get over a too direct notion of such a relationship, cast doubts on inductive inference and started conceiving in a new (strictly non-inductivist) manner the relationship between theoretical and observational propositions.Stefano Gatteistefano.gattei@imtlucca.it