Teoria di scattering per NLS

In questa tesi ci occupiamo dell'equazione di Schrödinger nonlineare, analizziamo buona positura locale e globale. Trattiamo inoltre la teoria di scattering nel caso sottocritico, sia per l'equazione focalizzante sia per quella focalizzante. Con metodi di concentrazione-compattezza/rigidità forniamo una condizione sufficiente per esistenza globale e scattering che non si limita alla piccolezza del dato iniziale. Questo metodo è un'implementazione a livelllo di problemi di evoluzione della celebre tecnica di concentrazione-compattezza introdotta da Lion negli anni '80 per studiare la mancanza di compattezza in certe immersioni di Sobolev

Inter-Organizational Learning and Collective Memory in Small Firms Clusters: an Agent-Based Approach

Literature about Industrial Districts has largely emphasized the importance of both economic and social factors in determining the competitiveness of these particular firms\' clusters. For thirty years, the Industrial District productive and organizational model represented an alternative to the integrated model of fordist enterprise. Nowadays, the district model suffers from competitive gaps, largely due to the increase of competitive pressure of globalization. This work aims to analyze, through an agent-based simulation model, the influence of informal socio-cognitive coordination mechanisms on district\'s performances, in relation to different competitive scenarios. The agent-based simulation approach is particularly fit for this purpose as it is able to represent the Industrial District\'s complexity. Furthermore, it permits to develop dynamic analysis of district\'s performances according to different types of environment evolution. The results of this work question the widespread opinion that cooperative districts can answer to environmental changes more effectively that non-cooperative ones. In fact, the results of simulations show that, in the presence of turbulent scenarios, the best performer districts are those in which cooperation and competition, trust and opportunism balance out.Firm Networks, Collective Memory, Agent Based Models, Uncertainty

A debate dashboard to enhance on-line knowledge sharing

Purpose – Web 2.0 technologies have radically modified the way in which knowledge is created, managed and shared, improving productivity and accelerating innovation processes for the enterprises. These technologies have allowed enterprises to produce knowledge, leverage collective intelligence and build social capital on a scale that was unimaginable a few years ago. In this paper we focus on a particular kind of web-based collaborative platforms known as argument mapping tools and we discuss the main barriers to the adoption of them. Literature has proved that these argument mapping tools provide large and small and medium enterprise with several advantages, but nevertheless, they have low level adoption. In this paper we explore new technological solutions to support the adoption of argument mapping tools. In particular, we propose the design of a Debate Dashboard to provide visual feedback to support online deliberation. These visual feedback aims at compensating the loss of information due to the mediation of the technology. The Debate Dashboard is composed of a set of suitable visualization tools that have been selected on the basis of a literature review of the visualization tools. Design/methodology/approach - We propose a literature review of existing visualization tools. Building on the literature review we selected thirty visualization tools, which have been classified on the basis of the kind of feedback they are able to provide. We identify three classes of feedback: Community feedback (identikit of users), Interaction feedback (about how users interact) and Absorption feedback (about generated content and its organization). We distilled the Debate Dashboard features by building on results of a literature review on Web 2.0 tools for data visualization. As output of literature review we selected six visualization tools. We consider these selected tools as a sort of starting point. Indeed, our aim is the improvement of them through the addition of further features and functions in order to make them more effective in providing feedback. Originality/value – Our paper enriches the debate about computer mediated conversation and visualization tools. We propose a Dashboard prototype to augment collaborative knowledge mapping tools by providing visual feedback on conversations. The Dashboard will provide at the same time three different kinds of feedback about: details of the participants to the conversation, interaction processes and generated content. This will allow the improvement of the benefits and reduce the costs deriving from the use of mapping tools. Moreover, another important novelty is that visualization tools will be integrated to mapping tools, as until now they have been used only to visualize data contained in forums (as Usenet or Slash.dot), chat or email archives Practical implications – The Dashboard provides feedback about participants, interaction processes and generated contents, thus supporting the adoption of mapping tools as technologies able to foster knowledge sharing among remote workers or/and customers and supplier. The integration of Debate Dashboard with common online argument mapping tools aims at enabling the following advantages: 1. Reduction of misunderstanding; 2. Reduction of cognitive effort required to use argument mapping tools; 3. Improvement of the exploration and the analysis of the maps - the Debate Dashboard feedback improves the usability of the object (the map), thus allowing users to pitch into the conversation in the right place

Strong ill-posedness in W1,∞W^{1, \infty} of the 2d stably stratified Boussinesq equations and application to the 3d axisymmetric Euler Equations

We prove the strong ill-posedness in the sense of Hadamard of the two-dimensional Boussinesq equations in $W^{1, \infty}(\mathbb{R}^2)$ without boundary, extending to the case of systems the method that Shikh Khalil \& Elgindi arXiv:2207.04556v1 developed for scalar equations. We provide a large class of initial data with velocity and density of small $W^{1, \infty}(\mathbb{R}^2)$ size, for which the horizontal density gradient has a strong $L^{\infty}(\mathbb{R}^2)$-norm inflation in infinitesimal time, while the vorticity and the vertical density gradient remain bounded. Furthermore, exploiting the three dimensional version of Elgindi's decomposition of the Biot-Savart law, we apply the method to the three-dimensional axisymmetric Euler equations with swirl and away from the vertical axis, showing that a large class of initial data with velocity field uniformly bounded in $W^{1, \infty}(\mathbb{R}^2)$ provides a solution whose swirl component has a strong $W^{1, \infty}(\mathbb{R}^2)$-norm inflation in infinitesimal time, while the potential vorticity remains bounded at least for small times. Finally, the $L^\infty$-norm inflation of the swirl (and the vorticity field) is quantified from below by an explicit lower bound which depends on time, the size of the data and it is valid for small times

Modelling Networked Cognition: A Socio-Computational Approach

In this paper an agent-based model is proposed in which effects of collective cognition are represented via the operazionalization of the construct of collective memory. The model is aimed at representing an evolving local networks of suppliers and final firms competing among them, making alliances and selling products on the market in the presence of environmental instability. A set of hypothesis has been tested in order to evaluate the influence on network’s performances of collective memory. Through the proposed model, this article illustrates advantages and limitations of computer based models to investigate collective cognition. The extent to which computational approaches can be used to model collective cognitive constructs such as collective memory and learning and their influence on social action is examined. Finally, implications for research and practice on organizational cognition resulting from a social computation view are outlined

Long time solutions for quasi-linear Hamiltonian perturbations of Schr\"odinger and Klein-Gordon equations on tori

We consider quasi-linear, Hamiltonian perturbations of the cubic Schr\"odinger and of the cubic (derivative) Klein-Gordon equations on the $d$ dimensional torus. If $\varepsilon\ll1$ is the size of the initial datum, we prove that the lifespan of solutions is strictly larger than the local existence time $\varepsilon^{-2}$. More precisely, concerning the Schr\"odinger equation we show that the lifespan is at least of order $O(\varepsilon^{-4})$, in the Klein-Gordon case, we prove that the solutions exist at least for a time of order $O(\varepsilon^{-{8/3}^{-}})$ as soon as $d\geq3$. Regarding the Klein-Gordon equation, our result presents novelties also in the case of semi-linear perturbations: we show that the lifespan is at least of order $O(\varepsilon^{-{10/3}^-})$, improving, for cubic non-linearities and $d\geq4$, the general results in [17,24].Comment: 49 pag, a reference has been added, some typos correcte

Lichen amyloidosus: a new therapeutic approach.

The result of topical treatment by dimethyl sulphoxide (DMSO) in a patient with lichen amyloidosus is reported. Itching improved within five days of therapy. Remarkable flattening of the papules was obtained within two weeks. The clinical result was confirmed by histological examination which revealed partially disappearance of amyloid deposits

Human-Centered Design for Individual and Social Well-being: Editorial Preface

As digital technology use becomes widespread, its unintended consequences ranging from personal health to societal righteousness are under more scrutiny. Increasingly, digital designers are accused of not being considerate enough of the depth of their creations, and their impacts on our well-being. In this special issue, we explore an alternative, genuinely human-centered approach to technology design focusing on well-being and making our interactions with digital technology more meaningful, purposeful, and sustainable. To this end, the editorial starts with a brief review of the history of research that led to the growing field of digital well-being. We then introduce the Digital Well-being Design Framework, which goes beyond the ego-centric approach in human-centered design, and is multi-layered with self (intrapersonal), social (interpersonal), and transcendent (extra-personal) levels. Similar topics in related AIS journals are summarized, followed by the application of our framework to introduce and position the papers in this special issue. Our special issue aims to bring the topic of digital well-being to the forefront of the information systems research community and launch a new era of genuinely human-centered design

The age of digital entrepreneurship

Understanding the circumstances and reasons which facilitate digital entrepreneurship (DE) is of interest to academic research, and guides business practice, as well as public policies aiming at supporting this phenomenon given its positive impacts in terms of job creation and economic growth. We define some relevant concepts and briefly map current research using a perspective that focuses on the way digital entrepreneurs create digital value by acquiring, processing, and distributing digital information. Through the adoption of a digital information processing perspective, we provide a micro-level approach to research on digital entrepreneurship (DE) that complements existing literature on DE focused at the systemic level (digital entrepreneurship ecosystems and in the digital platforms economy). We show how these two approaches can be jointly used to identify major research streams on DE: digital business models, the digital entrepreneurship process and the creation of digital start-ups, DE in digital platforms, and entrepreneurial digital ecosystems. As is the case with existing DE frameworks, our approach concurs in putting emphasis on the new collaborative and social dynamics enabled by digital tools to support knowledge sharing and facilitate opportunity recognition