1,721,092 research outputs found
Nonlocal Elliptic PDEs with General Nonlinearities
Full text linkIn this thesis we investigate how the nonlocalities affect the study of different PDEs coming from physics, and we analyze these equations under almost optimal assumptions of the nonlinearity. In particular, we focus on the fractional Laplacian operator and on sources %nonlinearities
involving convolution with the Riesz potential, as well as on the interaction of the two, and we aim to do it through variational and topological methods.
We examine both quantitative and qualitative aspects, proving multiplicity of solutions for nonlocal nonlinear problems with free or prescribed mass, showing regularity, positivity, symmetry and sharp asymptotic decay of ground states, and exploring the influence of the topology of a potential well in presence of concentration phenomena. On the nonlinearities we consider general assumptions which avoid monotonicity and homogeneity: this generality obstructs the use of classical variational tools and forces the implementation of new ideas.
Throughout the thesis we develop some new tools: among them, a Lagrangian formulation modeled on Pohozaev mountains is used for the existence of normalized solutions, annuli-shaped multidimensional paths are built for genus-based multiplicity results, a fractional chain rule is proved to treat concave powers, and a fractional center of mass is defined to detect semiclassical standing waves. We believe that these tools could be used to face problems in different frameworks as well
Asymptotic decay of solutions for sublinear fractional Choquard equations
Full text linkGoal of this paper is to study the asymptotic behaviour of the solutions of the following doubly nonlocal equation (−Δ)su+μu=(Iα∗F(u))f(u)onRNwhere s∈(0,1), N≥2, α∈(0,N), μ>0, Iα denotes the Riesz potential and F(t)=∫0tf(τ)dτ is a general nonlinearity with a sublinear growth in the origin. The found decay is of polynomial type, with a rate possibly slower than [Formula presented], and it complements the decays obtained in the linear and superlinear cases in Cingolani et al. (2022); D'Avenia et al. (2015). Differently from the local case s=1 in Moroz and Van Schaftingen (2013), new phenomena arise connected to a new “s-sublinear” threshold that we detect on the growth of f. To gain the result we in particular prove a Chain Rule type inequality in the fractional setting, suitable for concave powers
Development of Optimization Algorithms for Shipboard Applications
No full textThis thesis explores the application of optimization algorithms to encrease the performance of ships. Several algorithms based on Mixed Integer Linear Programming (MILP) have been developed to address energy management, sizing, and scheduling problems.
A Model Predictive Control (MPC) - based Energy Management System (EMS) is introduced to optimize the efficiency of hybrid shipboard power systems while ensuring secure operations. The proposed approach utilizes a MILP formulation to address process constraints, N-1 security requirements, and carbon intensity indicator limits. It also incorporates predictive modeling of ship load and speed using Recurrent Neural Networks (RNN).
For power electronic system design, a MILP-based optimization algorithm is proposed to determine the optimal number and ratings of Power Electronics Building Blocks (PEBBs). This approach balances design trade-offs and ensures efficient integration within advanced distribution systems, such as the Navy Integrated Power and Energy Corridor (NiPEC).
Finally, an optimal scheduling strategy is proposed for a smart inland port, integrating renewable energy resources, battery storage, and ferry allocation between ports. This strategy utilizes a state-transition model to optimize ferry routing and charging schedules while addressing population-driven transport demands.
The proposed optimization algorithms are validated through simulations exploited in Matlab, Simulink, and GAMS environments, demonstrating their scalability and robustness across various maritime applications. The results highlight the effectiveness of these approaches in improving operational efficiency, establishing trade-offs, and minimizing costs, thereby supporting their practical implementation in modern maritime systems
Normalized ground states for NLS equations with mass critical nonlinearities
No full textWe study normalized solutions to %the
nonlinear Schrödinger equations
where and the mass m>0 is given. Here, has an -critical growth, both at the origin and at infinity, that is, as and , where .
We continue the analysis started in \cite{CGIT24}, where we found two (possibly distinct) minimax values of the Lagrangian functional.
In this paper, we furnish explicit examples of satisfying \underline{b}<0<\overline{b}, \underline{b}=0<\overline{b}, and \underline{b}<0=\overline{b}; notice that in the power case . Moreover, we deal with the existence and non-existence of a solution with minimal energy.
Finally, we discuss the assumptions required on to obtain the existence of a positive solution for perturbations of
Disegno e Camera Lucida nel Carnet de voyage.
No full textDa sempre il viaggiatore disegna. Annota graficamente ciò che osserva per poterlo assimilare attraverso la traduzione in segni, estrapolando quei particolari che lo portano a sintetizzare la descrizione del reale. Gli strumenti del disegnatore in viaggio sono elementi che condizionano tempi e modi di realizzazione portando i diversi autori a scegliere modalità espressive nel rispetto delle differenti finalità. Nell'ottocento, le evoluzioni della Camera Obscura (la Camera Lucida e successivamente la Fotografia), in modo diverso, hanno portato a una velocizzazione della rappresentazione del reale. Proprio nell'era della fotografia digitale, che non obbliga l'autore all'analisi, la riscoperta di questo piccolo strumento ottico impone una relazione biunivoca tra conoscenza e sintesi attraverso il disegno. L'esperienza diretta ha portato a ridefinire i tempi di esecuzione delle vedute, dilatando quelli di progettazione e riducendo quelli della realizzazione. Operare sotto la guida dello strumento permette di mantenere rapporti proporzionali e prospettici, basi certe per la successiva implementazione con la vestizione grafica.
Nella dimensione del "carnet de voyage" dall'800 ad oggi, tale ridefinizione ha mostrato potenzialità che possono essere nuovi, attuali, veicoli di conoscenza.The traveler has always drawn. Graphically marking what he looks at, in order to assimilate it through a translation into signs, extrapolating those details that allow him to synthesize the description of reality. The tools of the drawer on the road affect the time and the manner of realization, driving the different authors to choose different modes of expression with respect to their different purposes.In the nineteenth century, the invention of the Camera Lucida and afterwards of the Photography (both evolutions of the Camera Obscura), in a different ways have led to a speeding up of the representationof reality. In the era of digital photography, which does not require the author to synthesize, the rediscovery of the Camera Lucida imposes a two-way relationship between knowledge and discretization, through ther process of drawing. Direct experience has led us to redefine the executiontimes of views, expanding the design part and reducing the production one. To operate under theguidance of the tool allows you to maintain proportional relationships and prospective, excellent basesfor a later improvement by a graphic dressing.In the dimension of the "carnet de voyage" from '800 to today, this redefinition has shown potentialthat may be new, current, vehicles of knowledge
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
A note on the inverse maximum principle on Carnot groups
Full text linkLet ΔG be a sublaplacian on a Carnot group, and let μ be a local measure on the open set Ω ⊂ G. If u ∈ L1l oc(Ω) is such that −ΔGu = μ, u ≥ 0 on Ω, then μc ≥ 0, where μc is the concentrated component of μ with respect to the G-capacity. This extends to the Carnot group setting a result contained in [9]
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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