AMS Acta
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Repository of the University of Bologna.

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Mostrando recursos 1 - 20 de 296

1.
The edit distance for Reeb graphs of surfaces - Di Fabio, Barbara; Landi, Claudia
Reeb graphs are structural descriptors that capture shape
properties of a topological space from the perspective of a chosen function. In this work we define a combinatorial metric for Reeb graphs of orientable surfaces in terms of the cost necessary to transform one graph into another by edit operations. The main contributions of this paper are the stability property and the optimality of this edit distance. More precisely, the stability result states that changes in the functions, measured by the maximum norm, imply not greater changes in the corresponding Reeb
graphs, measured by the edit distance. The optimality result states that our...

2.
Reeb graphs of surfaces are stable under function perturbations - Di Fabio, Barbara; Landi, Claudia
Reeb graphs are combinatorial signatures that capture shape
properties from the perspective of a chosen function. One of the
most important questions is whether Reeb graphs are robust against
function perturbations that may occur because of noise and
approximation errors in the data acquisition process. In this work
we tackle the problem of stability providing an editing distance
between Reeb graphs of orientable surfaces in terms of the cost
necessary to transform one graph into another by edit operations.
Our main result is that changes in the functions, measured by the
maximum norm, imply not greater changes in this distance, yielding
the stability property under function perturbations.

4.
Social capital, institutions and policy making - Savioli, Marco
Economic processes, consisting of interactions between human beings, exploit the social capital of persons endowed with specific culture and identities. The role of institutions and policy makers is to build positive social capital and exploit it to reach their objectives. However, social capital is elusive and has several dimensions by which to interpret its multifaceted functions in economics and society. We cannot forget, furthermore, that social capital sometimes is undesirable for society, for instance when used for unethical uses. Even so, it is widely accepted that social capital has stable and positive effects.

5.
Observation of abundant heat production from a reactor device and of isotopic changes in the fuel - Levi, Giuseppe; Evelyn, Foschi; Bo, Hoistad; Roland, Pettesson; Lars, Tegnér; Hanno, Essén
New results are presented from an extended experimental investigation of anomalous heat production in a special type of
reactor tube operating at high temperatures. The reactor, named E-Cat, is charged with a small amount of hydrogen-loaded
nickel powder plus some additives, mainly Lithium. The reaction is primarily initiated by heat from resistor coils around the
reactor tube. Measurements of the radiated power from the reactor were performed with high-resolution thermal imaging
cameras. The measurements of electrical power input were performed with a large bandwidth three-phase power analyzer.
Data were collected during 32 days of running in March 2014. The reactor operating...

6.
Terracotta Female Musicians from the Sanctuary of Fontana Calda,«Bullettin de Corrispondance Hellénique», Supp., École française d’Athènes, c.s. - Bellia, Angela
Résumé. Musiciennes de terre cuite du sanctuaire de Fontana Calda (Sicile). Dans les années 50 on a mis au jour dans le sanctuaire de Fontana Calda (Sicile centrale) un dépôt constitué de centaines de figurines de joueurs d’aulos, de tympanon, de cymbales, de harpe, ainsi que des groupes de joueurs d’aulos et de tympanon ; elles datent d’entre la fin du VIe s. et le début du IIIe s. Des figurines comparables ont été retrouvées sur de nombreux autres sites de Sicile et en particulier dans des sanctuaires qui étaient comme celui de Fontana Calda consacrés à des divinités chthoniennes....

7.
Sewage sludge: characteristics and recovery options - Bonfiglioli, Luca; Bianchini, Augusto; Pellegrini, Marco; Saccani, Cesare
In this paper, an overview on sewage sludge characteristics and recovery routes is presented. Starting from an analysis of typical sewage sludge characteristics as found in literature, the most promising disposal options are presented. A focus on incinerated sewage sludge ash (ISSA) follows. Most of the authors agree on considering pyrolysis and gasification as the most viable treatments for sludge in the near future. For this reason, the last two chapters offer a brief description of these two processes and their products.

8.
Analisi delle prestazioni degli impianti fotovoltaici situati presso il laboratorio di ricerca e sviluppo HEnergia di Forlì - Bianchini, Augusto; Gambuti, Michele; Pellegrini, Marco; Saccani, Cesare
Nasce a Forlì un laboratorio innovativo di ricerca e sviluppodel gruppo Hera che si pone come obiettivo quello di studiare diverse tecnologie per la produzione di energia da fonte rinnovabile presenti sul mercato e acquisire il know-how necessario alla valutazione, progettazione e gestione di impianti di questa tipologia.
A partire dai dati climatici e di produzione elettrica acquisiti e disponibili nel database che gestisce tali informazioni, sono stati realizzati modelli di valutazione delle prestazioni delle diverse tecnologie fotovoltaiche presenti presso il laboratorio: in questo elaborato vengono presentate delle prime stime relative alla produttività di tre diversi impianti.

9.
Community-based Enterprises in Italy: Definition and Governance Models - Bandini, Federica; Renato, Medei; Claudio, Travaglini
In recent years, a new form of co-operative business is taking shape in Italy: the community-based enterprise, a community acting collectively at both management and business level, to pursue common goals. Community-based enterprises grow on a system of networks of free relationships among the members of a local community, with a high degree of reciprocity; when individuals work together in a business systems, relationships become social relationships. The complex of the community members’ relationships, objectives and expectations towards the company reflects necessarily on governance models that should follow a multistakeholder pattern. Multistakeholdership implies a direct and active participation of subjects...

10.
Reeb graphs of surfaces are stable under function perturbations - Di Fabio, Barbara; Landi, Claudia
Reeb graphs are combinatorial signatures that capture shape
properties from the perspective of a chosen function. One of the
most important questions is whether Reeb graphs are robust against
function perturbations that may occur because of noise and
approximation errors in the data acquisition process. In this work
we tackle the problem of stability providing an editing distance
between Reeb graphs of orientable surfaces in terms of the cost
necessary to transform one graph into another by edit operations.
Our main result is that changes in the functions, measured by the
maximum norm, imply not greater changes in this distance, yielding
the stability property under function perturbations.

11.
Social capital, institutions and policy making - Savioli, Marco
Economic processes, consisting of interactions between human beings, exploit the social capital of persons endowed with specific culture and identities. The role of institutions and policy makers is to build positive social capital and exploit it to reach their objectives. However, social capital is elusive and has several dimensions by which to interpret its multifaceted functions in economics and society. We cannot forget, furthermore, that social capital sometimes is undesirable for society, for instance when used for unethical uses. Even so, it is widely accepted that social capital has stable and positive effects.

12.
Both On and Under the Surface of Discourse: Tagged Corpora for
the Functional Description of Conjunctive Language - Cresswell, Andy
This paper reports an eight-stage procedure for tagging small specialised corpora with logical relations, grounded in the coding of two corpora of argumentative writing – one learner corpus, and one expert corpus. The tagset was developed out of Rhetorical Structure Theory. Tagging involved adjusting mark-up added by the RST Tool tree diagram program to produce a corpus with cocoa tags easily searchable with KWIC concordancing software. Results show disambiguation of form-function relationships in conjunction and a wide range of types of conjunctive language. Potential further applications in research and teaching are discussed.

13.
Italians in the ‘Old Shanghai’: a Preliminary Contribution - Piastra, Stefano
Besides other Western nationalities, ‘Old Shanghai’ also hosted an Italian community, which experienced, throughout the years, a slight development, particularly after the establishment there of the consulate of the Kingdom of Sardinia in 1860 (later kept by the new Kingdom of Italy), and the signing, in 1866, of a Sino-Italian Treaty (ratified in Shanghai in 1867). It was a small group, if compared with the English, the Americans or the French (from some dozens to some hundreds between the 19th and the 20th centuries), but it had distinctive spatial and socio-economic urban patterns: in ‘Old Shanghai’, there were specific areas...

16.
Filtrations induced by continuous functions - Di Fabio, Barbara; Frosini, Patrizio
In Persistent Homology and Topology, filtrations are usually given by introducing an ordered collection of sets or a continuous function from a topological space to $\R^n$. A natural question arises, whether these approaches are equivalent or not. In this paper we study this problem and prove that, while the answer to the previous question is negative in the general case, the approach by continuous functions is not restrictive with respect to the other, provided that some natural stability and completeness assumptions are made. In particular, we show that every compact and stable $1$-dimensional filtration of a compact
metric space is induced...

17.
G-invariant Persistent Homology - Frosini, Patrizio
Classical persistent homology is a powerful mathematical tool for shape comparison. Unfortunately, it is not tailored to study the action of transformation groups that are different from the group Homeo(X) of all self-homeomorphisms of a topological space X. This fact greatly restricts its use in applications. In order to obtain better lower bounds for the natural pseudo-distance d_G associated with a subgroup G of the group Homeo(X), we need to adapt persistent homology and consider G-invariant persistent homology. Roughly speaking, the main idea consists in defining persistent homology by means of a set of chains that is invariant under the...

18.
G-invariant Persistent Homology - Frosini, Patrizio
Classical persistent homology is not tailored to study the action of transformation groups different from the group Homeo(X) of all self-homeomorphisms of a topological space X. In order to obtain better lower bounds for the natural pseudo-distance d_G associated with a subgroup G of Homeo(X), we need to adapt persistent homology and consider G-invariant
persistent homology. Roughly speaking, the main idea consists in defining persistent homology by means of a set of chains that is invariant under the action of G. In this paper we formalize this idea, and prove the stability of G-invariant persistent homology with respect to the natural...

19.
G-invariant Persistent Homology - Frosini, Patrizio
Classical persistent homology is not tailored to study the action of transformation groups different from the group Homeo(X) of all self-homeomorphisms of a topological space X. In order to obtain better lower bounds for the natural pseudo-distance d_G associated with a subgroup G of Homeo(X), we need to adapt persistent homology and consider G-invariant
persistent homology. Roughly speaking, the main idea consists in defining persistent homology by means of a set of chains that is invariant under the action of G. In this paper we formalize this idea, and prove the stability of G-invariant persistent homology with respect to the natural...

20.
“Futurama II”. Tracking the ‘Presence of the Future’ in Contemporary Architecture Representations. - Maahsen-Milan, Andreina; Pellegrino, Margot
This text intends to discuss the profile of three architects belonging to the past century: Enzo Venturelli, Claude Parent and Roger Anger. The aim is to compare their representations to prefigure their ideal towns. Interest is even greater, if we hypothesize and sustain the existence of a link be-tween these three personalities which is far from being simply indirect. A new interpretation of the three authors highlights common cultural aspects. The identified links open up new prospects for investigation, substantiated by an exam of the works of these three architects. In particular, a spe-cific element is compared: the representation –...