1,720,975 research outputs found
Un'analisi del modello di sviluppo brasiliano: cambiamento strutturale, specializzazione commerciale e le politiche per l'innovazione.
Full text linkThe dissertation deals with the Brazilian economic model and the role of the State in managing the economy through industrial and innovation policies.
The first part of the dissertation is dedicated to the analysis of the productive structure and the international competitiveness of the Brazilian economy, while the second part focuses on the industrial and innovation policies implemented by the Brazilian government.
An analysis of the economy‟s structural change is conducted, pointing out which sectors have gained importance in terms of manufacturing value added during the economic reforms of the „90s and later on. A broad analysis of trade specialization is also conducted, and an investigation on the relationships between Brazil and its main trade partners is carried out, specifically focusing on China, currently its main trade partner. The trend in Foreign Direct Investments (FDI) flows is analysed, pointing out the increasing importance of the Brazilian multinationals in the international markets.
In order to evaluate the sustainability of the economic model, a broad evaluation of the government industrial and innovation policies is conducted to assess the consistency of those policies with the structural problems of the economy. In particular, policies to improve the international trade performance are analysed. Furthermore, programmes and policies to strengthen the National Innovation System (NIS) are evaluated, and an in depth analysis of the NIS is also carried out. In addition, one chapter deals with an important agent of the Brazilian NIS: the National Development Bank (BNDES) and its role in the credit market.
The increasing role of the State in managing the economy through industrial policies after several years of just “free markets” policies is positively evaluated, although some structural economic problems still remain
The minimum time function for the controlled Moreau's sweeping process
Full text linkLet C(t), t ≥ 0 be a Lipschitz set-valued map with closed and (mildly non-)convex
values and f (t, x, u) be a map, Lipschitz continuous w.r.t. x. We consider the problem of reaching a
target S within the graph of C subject to the differential inclusion x ∈ −N_{C(t)} (x) + G(t, x) starting
̇from x_0 ∈ C(t_0 ) in the minimum time T (t_0 , x_0 ). The dynamics is called a perturbed sweeping (or
Moreau) process. We give sufficient conditions for T to be finite and continuous and characterize T
through Hamilton–Jacobi inequalities. Crucial tools for our approach are characterizations of weak
and strong flow invariance of a set S subject to the inclusion. Due to the presence of the normal cone
N_{C(t)} (x), the right-hand side of the inclusion contains implicitly the state constraint x(t) ∈ C(t) and
is not Lipschitz continuous with respect to x
Hamilton–Jacobi–Bellman Approach for Optimal Control Problems of Sweeping Processes
No full textThis paper is concerned with a state constrained optimal control problem governed by a Moreau's sweeping process with a controlled drift. The focus of this work is on the Bellman approach for an infinite horizon problem. In particular, we focus on the regularity of the value function and on the Hamilton-Jacobi-Bellman equation it satisfies. We discuss a uniqueness result and we make a comparison with standard state constrained optimal control problems to highlight a regularizing effect that the sweeping process induces on the value function
Unbounded Control, Infimum Gaps, and Higher Order Normality
Full text linkIn optimal control theory one sometimes extends the minimization domain of a
given problem, with the aim of achieving the existence of an optimal control. However, this issue
is naturally confronted with the possibility of a gap between the original infimum value and the
extended one. Avoiding this phenomenon is not a trivial issue, especially when the trajectories are
subject to endpoint constraints. However, since the seminal works by Warga, some authors have
recognized ``normality"" of an extended minimizer as a condition guaranteeing the absence of an
infimum gap. Yet, normality is far from being necessary for this goal, a fact that makes the search
for weaker assumptions a reasonable aim. In relation to a control-affine system with unbounded
controls, in this paper we prove a sufficient no-gap condition based on a notion of higher order
normality, which is less demanding than the standard normality and involves iterated Lie brackets
of the vector fields defining the dynamics
An Optimal Control Approach to the Problem of the Longest Self-Supporting Structure
Full text linkThe characterization of the self-supporting slender structure with the furthest length is of interest both from a mechanical and biological point of view. Indeed, from a mechanical perspective, this classical problem was developed and studied with different methods, for example using similarity solutions and stable manifolds. However, none of them led to a complete analytical solution. On the other hand, plant structures such as tree branches or searcher shoots in climbing plants can be considered elastic cantilevered beams. In this paper, we formulate the problem as a non-convex optimisation problem with mixed state constraints. The problem is solved by analysing the corresponding relaxation. With this method, it is possible to obtain an analytical characterization of the cross-sectio
Online identification and control of PDEs via reinforcement learning methods
No full textWe focus on the control of unknown partial differential equations (PDEs). The system dynamics is unknown, but we assume we are able to observe its evolution for a given control input, as typical in a reinforcement learning framework. We propose an algorithm based on the idea to control and identify on the fly the unknown system configuration. In this work, the control is based on the state-dependent Riccati approach, whereas the identification of the model on Bayesian linear regression. At each iteration, based on the observed data, we obtain an estimate of the a-priori unknown parameter configuration of the PDE and then we compute the control of the correspondent model. We show by numerical evidence the convergence of the method for infinite horizon control problems
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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