A new global wheat marketmodel (GLOWMM) for the analysis of wheat export prices

Food commodity prices fluctuations have important impacts on poverty and food insecurity across the world. Conventional models have not provided a complete picture of recent price spikes in agricultural commodity markets, while there is an urgent need for appropriate policy responses. Perhaps new approaches are needed in order to better understand international spill-overs, the feedback between the real and the financial sectors and also the link between food and energy prices. In this paper, we present results from a new worldwide dynamic model that provides short and long-run impulse responses of wheat international prices to various real shocks.

Modellazione multibody di veicoli ferroviari: sviluppo ed implementazione di modelli innovativi per l'analisi del contatto ruota - rotaia

The wheel - rail contact analysis plays a fundamental role in the multibody modeling of railway vehicles. A good contact model must provide an accurate description of the global contact phenomena (contact forces and torques, number and position of the contact points) and of the local contact phenomena (position and shape of the contact patch, stresses and displacements). The model has also to assure high numerical efficiency (in order to be implemented directly online within multibody models) and a good compatibility with commercial multibody software (Simpack Rail, Adams Rail). The wheel - rail contact problem has been discussed by several authors and many models can be found in the literature. The contact models can be subdivided into two different categories: the global models and the local (or differential) models. Currently, as regards the global models, the main approaches to the problem are the so - called rigid contact formulation and the semi – elastic contact description. The rigid approach considers the wheel and the rail as rigid bodies. The contact is imposed by means of constraint equations and the contact points are detected during the dynamic simulation by solving the nonlinear algebraic differential equations associated to the constrained multibody system. Indentation between the bodies is not permitted and the normal contact forces are calculated through the Lagrange multipliers. Finally the Hertz’s and the Kalker’s theories allow to evaluate the shape of the contact patch and the tangential forces respectively. Also the semi - elastic approach considers the wheel and the rail as rigid bodies. However in this case no kinematic constraints are imposed and the indentation between the bodies is permitted. The contact points are detected by means of approximated procedures (based on look - up tables and simplifying hypotheses on the problem geometry). The normal contact forces are calculated as a function of the indentation while, as in the rigid approach, the Hertz’s and the Kalker’s theories allow to evaluate the shape of the contact patch and the tangential forces. Both the described multibody approaches are computationally very efficient but their generality and accuracy turn out to be often insufficient because the physical hypotheses behind these theories are too restrictive and, in many circumstances, unverified. In order to obtain a complete description of the contact phenomena, local (or differential) contact models are needed. In other words wheel and rail have to be considered elastic bodies governed by the Navier’s equations and the contact has to be described by suitable analytical contact conditions. The contact between elastic bodies has been widely studied in literature both in the general case and in the rolling case. Many procedures based on variational inequalities, FEM techniques and convex optimization have been developed. This kind of approach assures high generality and accuracy but still needs very large computational costs and memory consumption. Due to the high computational load and memory consumption, referring to the current state of the art, the integration between multibody and differential modeling is almost absent in literature especially in the railway field. However this integration is very important because only the differential modeling allows an accurate analysis of the contact problem (in terms of contact forces and torques, position and shape of the contact patch, stresses and displacements) while the multibody modeling is the standard in the study of the railway dynamics. In this thesis some innovative wheel – rail contact models developed during the Ph. D. activity will be described. Concerning the global models, two new models belonging to the semi – elastic approach will be presented; the models satisfy the following specifics: 1) the models have to be 3D and to consider all the six relative degrees of freedom between wheel and rail 2) the models have to consider generic railway tracks and generic wheel and rail profiles 3) the models have to assure a general and accurate handling of the multiple contact without simplifying hypotheses on the problem geometry; in particular the models have to evaluate the number and the position of the contact points and, for each point, the contact forces and torques 4) the models have to be implementable directly online within the multibody models without look - up tables 5) the models have to assure computation times comparable with those of commercial multibody software (Simpack Rail, Adams Rail) and compatible with RT and HIL applications 6) the models have to be compatible with commercial multibody software (Simpack Rail, Adams Rail). The most innovative aspect of the new global contact models regards the detection of the contact points. In particular both the models aim to reduce the algebraic problem dimension by means of suitable analytical techniques. This kind of reduction allows to obtain an high numerical efficiency that makes possible the online implementation of the new procedure and the achievement of performance comparable with those of commercial multibody software. At the same time the analytical approach assures high accuracy and generality. Concerning the local (or differential) contact models, one new model satisfying the following specifics will be presented: 1) the model has to be 3D and to consider all the six relative degrees of freedom between wheel and rail 2) the model has to consider generic railway tracks and generic wheel and rail profiles 3) the model has to assure a general and accurate handling of the multiple contact without simplifying hypotheses on the problem geometry; in particular the model has to able to calculate both the global contact variables (contact forces and torques) and the local contact variables (position and shape of the contact patch, stresses and displacements) 4) the model has to be implementable directly online within the multibody models 5) the model has to assure high numerical efficiency and a reduced memory consumption in order to achieve a good integration between multibody and differential modeling (the base for the local contact models) 6) the model has to be compatible with commercial multibody software (Simpack Rail, Adams Rail). In this case the most innovative aspects of the new local contact model regard the contact modeling (by means of suitable analytical conditions) and the implementation of the numerical algorithms needed to solve the discrete problem arising from the discretization of the original continuum problem. Moreover, during the development of the local model, the achievement of a good compromise between accuracy and efficiency turned out to be very important to obtain a good integration between multibody and differential modeling. At this point the contact models has been inserted within a 3D multibody model of a railway vehicle to obtain a complete model of the wagon. The railway vehicle chosen as benchmark is the Manchester Wagon the physical and geometrical characteristics of which are easily available in the literature. The model of the whole railway vehicle (multibody model and contact model) has been implemented in the Matlab/Simulink environment. The multibody model has been implemented in SimMechanics, a Matlab toolbox specifically designed for multibody dynamics, while, as regards the contact models, the CS – functions have been used; this particular Matlab architecture allows to efficiently connect the Matlab/Simulink and the C/C++ environment. The 3D multibody model of the same vehicle (this time equipped with a standard contact model based on the semi - elastic approach) has been then implemented also in Simpack Rail, a commercial multibody software for railway vehicles widely tested and validated. Finally numerical simulations of the vehicle dynamics have been carried out on many different railway tracks with the aim of evaluating the performances of the whole model. The comparison between the results obtained by the Matlab/ Simulink model and those obtained by the Simpack Rail model has allowed an accurate and reliable validation of the new contact models. In conclusion to this brief introduction to my Ph. D. thesis, we would like to thank Trenitalia and the Regione Toscana for the support provided during all the Ph. D. activity. Moreover we would also like to thank the INTEC GmbH, the society the develops the software Simpack Rail, with which we are currently working together to develop innovative toolboxes specifically designed for the wheel rail contact analysis.

Insolvenza transfrontaliera e giurisdizione: l'esperienza del regolamento (CE) n. 1346 del 2000

L’elaborato è strutturato in quattro parti: la prima è dedicata all’inquadramento del background normativo. L’autrice affronta, con un approccio ricostruttivo, i precedenti alla redazione del regolamento e le difficoltà incontrate a causa delle resistenze degli Stati membri. Si sofferma altresì sulle norme UNCITRAL, anch’esse oggetto nel recente periodo, di numerose implementazioni. La seconda parte fotografa il ruolo della Corte di Giustizia nell’interpretazione del regolamento n. 1346/2000 ed individua i concetti fondamentali del regolamento: l’universalità attenuata, il campo di applicazione soggettivo del regolamento, la legge applicabile, il principio dell’automatico riconoscimento delle decisioni e la correlata tematica dell’ordine pubblico, nonché la figura del curatore. Si approfondisce l’attività degli Stati membri nel dotarsi di norme di coordinamento ( esemplare il caso della Spagna e della Germania) sottolineando il silenzio del legislatore italiano che, nonostante le numerose riforme in materia, a tutt’oggi non ha ideato un sistema in grado di coordinare la normativa nazionale con la struttura del regolamento europeo. Nella terza parte l'autrice approfondisce la giurisdizione nel regolamento n. 1346/2000. Si individuano le parole chiave: Comi e dipendenza, i cui significati sono sfumati seguendo le posizioni della Corte di Giustizia, (Leading Case Eurofood sino a Interedil) e si mette in discussione, nel panorama attuale, la tenuta di tali criteri giurisdizionali. Sempre intorno al concetto di Comi, si analizzano: la giurisdizione verso gruppi di imprese disciplina assente nel regolamento, i rapporti tra procedura principale e secondaria , la giurisdizione in materia di azioni connesse e/o correlate (Gourdain vs Nadler/Seagon vs Deko Marty). Il capitolo conclusivo offre una panoramica delle proposte finalizzate ad un’implementazione della struttura del regolamento sull’insolvenza. Numerose, infatti, sono le proposte a livello dottrinale e da parte degli organi comunitari in vista della scadenza del Report della Commissione Europea sulla applicazione del regolamento 1346 del 2000 (art. 46).

Oltre Oceano: Altri orizzonti del possibile. Epistemiologie di Abya Yala e progettualità esistenziale “Lekil Kuxlejal,Sumak Kawsay, Kajkrasa Ruyina”. Filosofie della Terra per una Pedagogia del Buen Vivir

Questo elaborato propone alcune riflessioni sulla necessità urgente di un nuovo paradigma educativo, mediante la re-organizzazione delle scienze della conoscenza, scienze in parole di Morin, “disgiunte e frazionate, inadeguate ad affrontare problemi che richiedono oggi approcci multidisciplinari”. La sfida: affrontare i nuovi problemi di una convivenza planetaria, attraverso le connessioni del pensiero ecologico, in questo studio asse centrale delle cosmovisioni e della Sapienza ancestrale dei Popoli di AbyaYala (America Latina). Popoli in cui la Vita come orizzonte di Armonia ed Equilibrio si concretizza in pratiche di Vita Quotidiana grazie ad una Pedagogia del BuenVivir, inclusiva e partecipativa, rispettosa della diversità biologica e delle differenze culturali, nonché della Sacralità della Terra e della Vita in tutte le sue manifestazioni. La cornice teorica considerata fa riferimento in modo particolare a: L’Ecologia della Mente (Bateson); Il problematicismo Pedagogico e l’Educazione alla Progettualità Esistenziale (G.M.Bertin, Contini); l’Ecologia dei Saperi e le Epistemologie del Sud (Boaventura di Sousa Santos, sociologo portoghese), in modo da tessere ponti di dialogo fra le diverse discipline, in particolare fra la pedagogia, la geografia, l’antropologia, la filosofia, la sociologia, la letteratura, il diritto e anche con le neuroscienze.

La tutela del contribuente nello scambio di informazioni tra Stati Membri UE

Questo elaborato analizza nella dimensione Eurounitaria ed Internazionale il tema della cooperazione amministrativa tributaria attuata tramite lo scambio di informazioni tra Stati Membri UE. La prospettiva presa in considerazione, tema centrale della presente studio, è quella del contribuente coinvolto nello scambio informativo transnazionale, con lo scopo di stabilire se all’interno delle norme internazionali ed europee che regolano lo strumento e negli ordinamenti nazionali, a cui esse rimandano, esista una effettiva tutela del contribuente. L’attenzione viene necessariamente posta all’ambito applicativo delle norme Europee ed Internazionali che disciplinano lo scambio di informazioni, evidenziandone in primis la struttura, la “fisiologia” e successivamente l’aspetto “patologico” discendente dall’imprescindibile esigenza informativa, con riguardo alle fattispecie tributarie, degli Stati Sovrani nel nuovo contesto globale. Questa ricerca si propone di individuare i vuoti giuridici e le carenze di tutele insite nelle procedure di scambio di informazioni e contestualmente di appurare l’esistenza nell’ordinamento Tributario Europeo, grazie al contributo interpretativo della Giurisprudenza della Corte di Giustizia ed ai principi sanciti dalla Carta dei diritti Fondamentali dell’Unione Europea nonché dalla convenzione CEDU, di un insieme di “diritti europei del contribuente” invocabili nel contesto collaborativo tra Stati Membri UE attuato tramite lo scambio di informazioni.

Self-Organizing Mechanisms for Task Allocation in a Knowledge-Based Economy

A prevalent claim is that we are in knowledge economy. When we talk about knowledge economy, we generally mean the concept of “Knowledge-based economy” indicating the use of knowledge and technologies to produce economic benefits. Hence knowledge is both tool and raw material (people’s skill) for producing some kind of product or service. In this kind of environment economic organization is undergoing several changes. For example authority relations are less important, legal and ownership-based definitions of the boundaries of the firm are becoming irrelevant and there are only few constraints on the set of coordination mechanisms. Hence what characterises a knowledge economy is the growing importance of human capital in productive processes (Foss, 2005) and the increasing knowledge intensity of jobs (Hodgson, 1999). Economic processes are also highly intertwined with social processes: they are likely to be informal and reciprocal rather than formal and negotiated. Another important point is also the problem of the division of labor: as economic activity becomes mainly intellectual and requires the integration of specific and idiosyncratic skills, the task of dividing the job and assigning it to the most appropriate individuals becomes arduous, a “supervisory problem” (Hogdson, 1999) emerges and traditional hierarchical control may result increasingly ineffective. Not only specificity of know how makes it awkward to monitor the execution of tasks, more importantly, top-down integration of skills may be difficult because ‘the nominal supervisors will not know the best way of doing the job – or even the precise purpose of the specialist job itself – and the worker will know better’ (Hogdson,1999). We, therefore, expect that the organization of the economic activity of specialists should be, at least partially, self-organized. The aim of this thesis is to bridge studies from computer science and in particular from Peer-to-Peer Networks (P2P) to organization theories. We think that the P2P paradigm well fits with organization problems related to all those situation in which a central authority is not possible. We believe that P2P Networks show a number of characteristics similar to firms working in a knowledge-based economy and hence that the methodology used for studying P2P Networks can be applied to organization studies. Three are the main characteristics we think P2P have in common with firms involved in knowledge economy: - Decentralization: in a pure P2P system every peer is an equal participant, there is no central authority governing the actions of the single peers; - Cost of ownership: P2P computing implies shared ownership reducing the cost of owing the systems and the content, and the cost of maintaining them; - Self-Organization: it refers to the process in a system leading to the emergence of global order within the system without the presence of another system dictating this order. These characteristics are present also in the kind of firm that we try to address and that’ why we have shifted the techniques we adopted for studies in computer science (Marcozzi et al., 2005; Hales et al., 2007 [39]) to management science.

Development of a new galaxy classification technique and its application to the zCOSMOS survey

The purpose of this Thesis is to develop a robust and powerful method to classify galaxies from large surveys, in order to establish and confirm the connections between the principal observational parameters of the galaxies (spectral features, colours, morphological indices), and help unveil the evolution of these parameters from $z \sim 1$ to the local Universe. Within the framework of zCOSMOS-bright survey, and making use of its large database of objects ($\sim 10\,000$ galaxies in the redshift range $0 < z \lesssim 1.2$) and its great reliability in redshift and spectral properties determinations, first we adopt and extend the \emph{classification cube method}, as developed by Mignoli et al. (2009), to exploit the bimodal properties of galaxies (spectral, photometric and morphologic) separately, and then combining together these three subclassifications. We use this classification method as a test for a newly devised statistical classification, based on Principal Component Analysis and Unsupervised Fuzzy Partition clustering method (PCA+UFP), which is able to define the galaxy population exploiting their natural global bimodality, considering simultaneously up to 8 different properties. The PCA+UFP analysis is a very powerful and robust tool to probe the nature and the evolution of galaxies in a survey. It allows to define with less uncertainties the classification of galaxies, adding the flexibility to be adapted to different parameters: being a fuzzy classification it avoids the problems due to a hard classification, such as the classification cube presented in the first part of the article. The PCA+UFP method can be easily applied to different datasets: it does not rely on the nature of the data and for this reason it can be successfully employed with others observables (magnitudes, colours) or derived properties (masses, luminosities, SFRs, etc.). The agreement between the two classification cluster definitions is very high. ``Early'' and ``late'' type galaxies are well defined by the spectral, photometric and morphological properties, both considering them in a separate way and then combining the classifications (classification cube) and treating them as a whole (PCA+UFP cluster analysis). Differences arise in the definition of outliers: the classification cube is much more sensitive to single measurement errors or misclassifications in one property than the PCA+UFP cluster analysis, in which errors are ``averaged out'' during the process. This method allowed us to behold the \emph{downsizing} effect taking place in the PC spaces: the migration between the blue cloud towards the red clump happens at higher redshifts for galaxies of larger mass. The determination of $M_{\mathrm{cross}}$ the transition mass is in significant agreement with others values in literature.

Development Aid to Water Management in Mali: The Actors, ‘Global’ Paradigms, and ‘Local’ Translations

Development aid involves a complex network of numerous and extremely heterogeneous actors. Nevertheless, all actors seem to speak the same ‘development jargon’ and to display a congruence that extends from the donor over the professional consultant to the village chief. And although the ideas about what counts as ‘good’ and ‘bad’ aid have constantly changed over time —with new paradigms and policies sprouting every few years— the apparent congruence between actors more or less remains unchanged. How can this be explained? Is it a strategy of all actors to get into the pocket of the donor, or are the social dynamics in development aid more complex? When a new development paradigm appears, where does it come from and how does it gain support? Is this support really homogeneous? To answer the questions, a multi-sited ethnography was conducted in the sector of water-related development aid, with a focus on 3 paradigms that are currently hegemonic in this sector: Integrated Water Resources Management, Capacity Building, and Adaptation to Climate Change. The sites of inquiry were: the headquarters of a multilateral organization, the headquarters of a development NGO, and the Inner Niger Delta in Mali. The research shows that paradigm shifts do not happen overnight but that new paradigms have long lines of descent. Moreover, they require a lot of work from actors in order to become hegemonic; the actors need to create a tight network of support. Each actor, however, interprets the paradigms in a slightly different way, depending on the position in the network. They implant their own interests in their interpretation of the paradigm (the actors ‘translate’ their interests), regardless of whether they constitute the donor, a mediator, or the aid recipient. These translations are necessary to cement and reproduce the network.

Global cities, global literature: New York e Tokyo nella narrativa contemporanea

Scopo del lavoro è quello di tracciare un parallelismo tra la narrativa giapponese e angloamericana contemporanea, viste come parte di un sistema di significati che trascende la dimensione nazionale e si installa invece in una dinamica di tipo globale. Le opere letterarie prese in considerazione sono alcune fra quelle ambientate nelle due vere e proprie capitali culturali dei paesi, rispettivamente New York per gli Stati Uniti e Tōkyō per il Giappone. Spunto di partenza dell’analisi è stato il concetto di “global city”, formulato dalla studiosa e sociologa Saskia Sassen, che permette di mettere in relazione dal punto di vista economico, strutturale ma anche sociale le città di New York e Tōkyō. Tale formulazione consente infatti di ragionare in maniera motivata sull’esistenza di un rapporto di flussi di scambio di tipo culturale e, parallelamente, sull’acquisizione di una dimensione di tipo transnazionale di soggetti e tematiche della letteratura. In questo senso, il rapporto tra economia e globalizzazione evidenziato da Sassen può essere paragonato a quello che intercorre tra la letteratura e la globalizzazione. Punto di snodo metodologico del lavoro è rappresentato dall’analisi dello spazio urbano, esaminato sia in chiave urbanistico-architettonica che più specificamente letteraria.

Symbolic Dynamics Analysis: a new methodology for foetal heart rate variability analysis

Cardiotocography (CTG) is a widespread foetal diagnostic methods. However, it lacks of objectivity and reproducibility since its dependence on observer's expertise. To overcome these limitations, more objective methods for CTG interpretation have been proposed. In particular, many developed techniques aim to assess the foetal heart rate variability (FHRV). Among them, some methodologies from nonlinear systems theory have been applied to the study of FHRV. All the techniques have proved to be helpful in specific cases. Nevertheless, none of them is more reliable than the others. Therefore, an in-depth study is necessary. The aim of this work is to deepen the FHRV analysis through the Symbolic Dynamics Analysis (SDA), a nonlinear technique already successfully employed for HRV analysis. Thanks to its simplicity of interpretation, it could be a useful tool for clinicians. We performed a literature study involving about 200 references on HRV and FHRV analysis; approximately 100 works were focused on non-linear techniques. Then, in order to compare linear and non-linear methods, we carried out a multiparametric study. 580 antepartum recordings of healthy fetuses were examined. Signals were processed using an updated software for CTG analysis and a new developed software for generating simulated CTG traces. Finally, statistical tests and regression analyses were carried out for estimating relationships among extracted indexes and other clinical information. Results confirm that none of the employed techniques is more reliable than the others. Moreover, in agreement with the literature, each analysis should take into account two relevant parameters, the foetal status and the week of gestation. Regarding the SDA, results show its promising capabilities in FHRV analysis. It allows recognizing foetal status, gestation week and global variability of FHR signals, even better than other methods. Nevertheless, further studies, which should involve even pathological cases, are necessary to establish its reliability.