3284 research outputs found
Sort by
New Advances on Multiple Criteria Hierarchy Process and the Choquet integral preference model
No full textIn Multiple Criteria Decision Aiding, a set of alternatives is evaluated on a family of criteria to deal with a choice, sorting or ranking problem. Not always the evaluation criteria are sited at the same level and, moreover, some type of interaction between criteria can be observed. To deal with the interaction between criteria, non-additive integrals and, in particular the Choquet integral, are used in literature.
In this thesis we considered the hierarchy of criteria and the interaction between criteria issues.
In particular, regarding the hierarchy of criteria, we extended the sorting method UTADIS and the Choquet integral preference model to deal with decision making problems presenting an hierarchy of criteria using the Multiple Criteria Hierarchy Process, recently introduced in literature. In both cases, an indirect way of providing preference information has been taken into account considering, for the extension of the UTADIS method, the Robust Ordinal Regression (ROR) while, for the extension of the Choquet integral preference model, ROR and Stochastic Multiobjective Acceptability Analysis (SMAA).
With respect to the interaction between criteria, we considered two ways of building a common scale necessary for the application of the Choquet integral. On one hand, we introduced an heuristic while, on the other hand, we applied the very well-known AHP method. Moreover, we proposed a new method, called NEMO-Ch, applying for the first time, the Choquet integral to the Evolutionary Multiobjective Optimization field. The new method permits to address the search to the region of the Pareto front most
interesting for the Decision Maker, taking into account her/his preferences
Cool Roofs for improving thermal performance of existing EU office buildings
No full textCool materials are characterized by having a high solar reflectance - which is able to reduce heat gains during daytime - and a high thermal emissivity that enables them to dissipate the heat absorbed throughout the day during night.
Despite the concept of cool roofs - i.e. the application of cool materials to roof surfaces - is well known in US since 1990s, many studies focused on their performance in both residential and commercial sectors under various climatic conditions for US countries, while only a few case studies are analyzed in EU countries.
The present thesis work aims at analyzing the thermal benefits due to their application to existing office buildings located in EU countries. Indeed, due to their weight in the existing buildings stock, as well as the very low rate of new buildings construction, the retrofit of office buildings is a topic of great concern worldwide.
After an in-depth characterization of the existing buildings stock in the EU, the thesis gives an insight into roof energy balance due to different technological solutions, showing in which cases and to what extent cool roofs are preferable.
A detailed description of the physical properties of cool materials and their availability on the market provides a solid background for the parametric analysis carried out by means of detailed numerical models that aims at evaluating cool roofs performance for various climates and office buildings configurations.
With the help of dynamic simulations, the thermal behavior of representative office buildings of the existing EU buildings stock is assessed in terms of thermal comfort and energy needs for air conditioning. The results, which consider several variations of building features that may affect the resulting energy balance, show how cool roofs are an effective strategy for reducing overheating occurrences and thus improving thermal comfort in any climate. On the other hand, potential heating penalties due to a reduction in the heat fluxes passing through the roof are taken into account, as well as the aging process of cool materials.
Finally, an economic analysis of the best performing models shows the boundaries for their economic convenience
Traiettorie di Flexicurity nell'ordinamento multilivello Problematiche aperte e possibili percorsi normativi verso una flessibilizzazione funzionale del mercato del lavoro
No full textIl presente lavoro svolge un'analisi teorica e pratica del modello di flexicurity proponendosi di individuare nuovi approcci normativi e strumenti pratici per il suo aggiornamento. Il lavoro è idealmente strutturato in tre parti. All'interno della prima sezione del lavoro, viene svolto uno studio preliminare del modello teorico di flexicurity, e un'analisi della successiva adattazione e attuazione all'interno del livello istituzionale eurounitario. All'interno della seconda sezione vengono analizzate le applicazioni pratiche del modello di flexicurity su due fragenti connessi con le transizioni occupazionali: da un lato la flessibilità in uscita, dall'altro i modelli di politiche attive del lavoro e gli attori istituzionali coinvolti. Nell'analisi di tali frangenti vengono evidenziati potenziali attriti sussistenti tra l'attuazione pratica del modello di flexicurtiy e la grammatica dei diritti sociali riconosciuti a livello sovranazionale. All'interno della terza, e ultima, sezione del lavoro si individua il "capability approach" ,elaborato da Amartya Sen, come criterio normativo di revisione del modello di flexicurity, e nel reddito minimo garantito uno degli strumenti necessari per raggiungere coerentemente tale aggiornamento
Multifaceted analysis for medical data understanding: from data acquisition to multidimensional signal processing to knowledge discovery
No full textLarge quantities of medical data are routinely generated each day in
the form of text, images and time signals, making evident the need
to develop new methodologies not only for the automatization of the
processing and management of such data, but also for the deeper un-
derstanding of the concepts hidden therein. The main problem that
arises is that the acquired data cannot always be in an appropriate
state or quality for quantitative analysis, and further processing is
often necessary in order to enable automatic processing and manage-
ment as well as to increase the accuracy of the results. Also, given
the multimodal nature of medical data uniform approaches no longer
apply and specific algorithm pipelines should be conceived and devel-
oped for each case.
In this dissertation we tackle some of the problems that occur in the
medical domain regarding different data modalities and an attempt to
understand the meaning of these data is made. These problems range
from cortical brain signal acquisition and processing to X-Ray image
analysis to text and genomics data-mining and subsequent knowledge
discovery
La partecipazione pubblica nei processi decisionali di Pianificazione dei Trasporti: un approccio ad agenti
No full textThe aim of the research is to give a contribution and an insight on the complex field of stakeholder involvement in transport planning, by analysing the role of decision-support methods and agent-based modelling in guiding a participation process.
The approach is twofold: from one side it is about to deeply understand the process of making a collective decision, by studying how the interaction among different actors can lead to a convergence of opinions towards a shared collective decision. From the other side, it is based on finding appropriate decision-support methods to help the group decision-making process.
Agent-based modelling and simulations have been used, in order to guide real participation processes and predict the results of an interaction process, and group multi criteria decision-making methods, to help taking consistent decisions based on several judgment criteria. The results of the research should help decision-makers and practitioners in dealing with multiple stakeholders and complex decisions and guiding the participation process
Biological control of postharvest phytopathogenic molds promoted by food-isolated yeasts
No full textThe mechanisms of action of antagonistic food-isolated yeasts, Wickerhamomyces anomalus, Metschnikowia pulcherrima, Aureobasidium pullulans and Saccharomyces cerevisiae, were evaluated. For each yeast species, different mechanisms involved in biocontrol activity against pathogenic molds, such as iron competition, production of cell wall-degrading enzymes, production of VOCs (Volatile Organic Compounds), and biofilm formation were clarified.
The second objective was to determine the efficacy of yeast strains in controlling gray mold caused by Botrytis cinerea on table grapes and strawberries, and green and blue mold decays caused by Penicillium digitatum and Penicillium italicum, respectively, on mandarin fruits. Therefore, subsequent studies investigated the potential use of locust bean gum (LBG) edible coating enriched with antagonistic yeast cells and of a commercial carrier (polyacrylammide hydrogel spheres) emitting antifungal VOCs produced by yeasts.
Among tested yeast strains, W. anomalus BS91 showed great antagonistic activity both by direct application of yeast cells and by application of VOCs. This strain is known to produce killer toxins that have been demonstrated to be exoglucanases, coded by the genes WaEXG1 and WaEXG2. To better understand the involvement of these genes in the antagonist activity of W. anomalus, characterization of the gene expression level of EXG1 and EXG2 in different yeast-host-pathogen interactions was carried out.
The present study demonstrated the efficacy of the selected yeasts as postharvest antifungal agents both by direct application and incorporation in an edible coating (LBG). Moreover, it has been demonstrated as production of VOCs can play an essential role in the antagonistic activity of BCAs, suggesting a future use of polyacrylammide hydrogel beads as VOCs emitters during the shelf-life
Low-Cost ZnO nanostructures: controlled synthesis and applications
No full textAdvances in nanotechnology is strongly dependent on research innovative nanostructured materials in nanostructure form. Multifunctional metal oxides have recently emerged as smart materials with a wide range of controllable properties leading to innovative device concepts. In particular, zinc oxide (ZnO) presents an unique combination of interesting properties such as non-toxicity, wide band-gap, high exciton binding energy at room temperature, piezoelectric behavior, high physical, chemical and mechanical stabilities [1]. Research on ZnO is an old story. In 1957, the New Jersey Zinc Company published a book entitled Zinc Oxide Rediscovered to promote the material s properties worthy to be further investigated [2]. Since then, ZnO have gained growing importance in the material science. In the last decade, ZnO nanostructures have been the focus of intensive studies, being an almost ideal systems both from a fundamental point of view (ease of nanostructuration, energy band bending, intrinsic and extrinsic defects, combination of polar and non polar planes, ) and from the applications (energy harvesting devices, sensors, biomedical devices, lighting, ). Many methods, both physical and chemical, have been employed for the synthesis of nanostructured ZnO; however most of the synthesis methods involve expensive experimental set up and sophisticated equipment. One of the basic requirements for nanomaterials to become industrially viable is the low production cost alongside the possibility to supply large amount of non-toxic material. In this regard, wet-chemical synthesis approaches are very appealing, having the advantages of easy use, low cost, reduced process temperatures and potential for scaling up. On the other hand, these kinds of synthesis have the shortcoming of lack of a good control and reproducibly. Overcoming these limitations and ensuring a high degree of reliability represent important challenges for modern material science. Among the wet-chemical approaches, chemical bath deposition (CBD) has emerged as the simplest and more versatile method for the synthesis of ZnO nanostructures. It is a chemical process, similar to an electroless deposition of solid phase from an aqueous solution. In this thesis, the attention is reserved to ZnO nanorods (NRs) and nanowalls (NWLs). ZnO NRs grown by CBD are among the most promising semiconducting nanostructures currently investigated for a wide range of applications. ZnO NWLs represent a new form of nanostructure with very large surface area, easy to synthesize by CBD on Al-covered substrate. Currently, some investigations have been focused on the microscopic mechanisms leading to the formation of ZnO NRs and NWLs, however some outstanding issues remain to be solved. A clearer comprehension of the growth mechanism in CBD and a better control of the synthesis are fundamental issues for taking full advantage of this technique. The work described in this thesis aims to deeper understand the mechanisms underlying the formation of ZnO NRs and NWLs under CBD conditions, attempting to clarify the role of synthetic parameters. Discerning their effects leads to enhance the control over the growth process. The potentialities of ZnO NRs and NWLs with optimized morphologies as critical components in technological solar cell, photocatalysis and sensing applications are also investigated.
[1] A. Ko³odziejczak-Radzimska, T. Jesionowski, Materials 7(4), 2833 (2014).
[2] Brown H. Zinc Oxide Rediscovered. New York (1957)
Eventi precoci nel processo di interazione tra Cellule Staminali Mesenchimali e Biomateriali polimerici (PSS e PEI Multilayers)
No full textIl mantenimento del fenotipo cellulare è di fondamentale importanza in qualsiasi applicazione di ingegneria tissutale. La possibilità di valutare in vitro le risposte cellulari a condizioni che mimano l'ambiente in vivo, può fornire una più completa conoscenza del comportamento dei biomateriali impiantati.
La realizzazione di multistrati di polielettroliti (PEMs) su materiali impiantabili è un'ottima strategia per realizzare condizioni che possano promuovere o prevenire l'adesione cellulare, o ancora più importante dirigerne e mantenerne il fenotipo. La versatilità dei PEMs fornisce la straordinaria possibilità di mimare il complesso ambiente extracellulare in vitro; variando le caratteristiche chimiche, meccaniche e topografiche è possibile promuovere l'adesione, la proliferazione, il differenziamento, la migrazione e l'espressione genica di praticamente tutti i tipi di cellule.
La grande varietà dei tessuti biologici e i fenotipi cellulari ad essi associati, impone che la scelta delle caratteristiche dei PEMs sia la più idonea possibile al tipo cellulare utilizzato per la rigenerazione di uno specifico tessuto. Lo strato terminale di un multilayer di polielettroliti è un fattore determinante nella biocompatibilità di un materiale e deve essere attentamente considerato sulla base delle interazioni cellulari desiderate per una particolare applicazione.
Lo studio si basa sulle interazioni tra cellule staminali mesenchimali umane e PEMs terminanti rispettivamente con Polistirensolfonato (PSS) e Polietilenimmina (PEI).
I PEMs PSS-ended sembrano avere le caratteristiche migliori per dirigere l'adesione ed il mantenimento del fenotipo delle hMSCs, mostrando una buona biocompatibilià.
Il PEMs PEI-ended induce significative modificazioni morfologiche ed un abbassamento dell'attività metabolica cellulare; tuttavia la forza di adesione cellulare a questa superficie è superiore rispetto a quella che si riscontra negli altri campioni.
Nello sviluppo di nuovi biomateriali per applicazioni in ingegneria tissutale, il PSS si comporta come un buon substrato di crescita per le cellule mesenchimali, a differenza del PEI che ne compromette alcune funzioni biologiche; tuttavia potrebbe essere interessante modulare alcuni parametri nella struttura del PEMs PEI-ended o funzionalizzarlo con opportuni fattori che ne riducano l'effetto negativo sulle hMSCs, al fine di poter sfruttare il forte ancoraggio cellulare indotto da questa superficie
Synthesis of natural-derived polyphenols as potential anticancer agents
No full textExtracts from plants or other organisms have been used for thousands of years as medicines and today a multitude of researchers continue to be inspired by the astonishing structural variety of natural products to identify potential lead compounds for drug discovery. In the simplest of terms, a natural product is a small molecule (generally with a molecular weight below 3000 Da) that is produced by a biological source; often the term is considered as synonymous for secondary metabolite and natural products research focuses on the biosynthesis and the study of chemical properties and biological functions of secondary metabolites. These are organic compounds not ubiquitous in all organisms, and represent an expression of the individuality of the species; secondary metabolites do not exert primary biological functions directly involved in the normal growth, development or reproduction of an organism but they may serve as chemical defense, intra- or interspecies communication, sexual attraction and to other purposes conferring an advantage to the organism producing them. The main families of secondary metabolites include isoprenoids, polyketides, alkaloids, non ribosomial peptides and polyphenols, these latter directly derived from shikimate pathway, as phenylpropanoids and lignans, or from a mixed biosynthetic pathway (shikimate/ acetate and/or malonate pathways), as stilbenoids or flavonoids.
My thesis is devoted to the family of polyphenols with the specific goal of synthesize new natural-derived polyphenols compounds and study their chemical and biological properties
Alimenti funzionali: profili di consumo e disponibilità a pagare prodotti da forno a base di lupino e fibra di arancia.
No full textL ambito nutrizionale è stato caratterizzato da numerosi studi scientifici orientati, inizialmente, sulle malattie causate da carenze nutrizionali e progressivamente volti alla scoperta di principi nutritivi associati alle linee guida per una corretta e sana alimentazione. Negli ultimi decenni, invece, si è assistito ad una crescente incidenza di patologie definite malattie dell abbondanza , in combinazione con errati stili di vita e di alimentazione (Hilliam, 1998; Sirò et al., 2008; Bonanno, 2012).
Il fenomeno degli alimenti funzionali, è stato analizzato negli ultimi anni da un vasto corpo letterario che ha fornito importanti, anche se ancora limitate, informazioni sulle caratteristiche del mercato e sull analisi del comportamento dei consumatori di tali alimenti (Bonanno 2012; Siro' et al., 2008).
In tale ambito, sono state approfondite ricerche esaminando studi sul grado di consapevolezza del consumatore rispetto a tali alimenti, sulle preferenze dei consumatori, sulle motivazioni che guidano l acquisto e la disponibilità a pagare i prodotti alimentari funzionali.
La necessità di approfondire le conoscenze sui comportamenti dei consumatori e le motivazioni che regolano le scelte verso beni alimentari con caratteristiche funzionali genera un interesse sia tra i produttori, indirizzati a soddisfare i bisogni che caratterizzano il mercato, sia tra le istituzioni pubbliche in grado di collegare la diffusione di questi alimenti con politiche di promozione della salute pubblica. L industria alimentare nel tentativo di lanciare un nuovo prodotto nel mercato incontra non poche difficoltà legate alla valutazione delle preferenze dei consumatori e la percezione verso le innovazioni tecnologiche utilizzate nella produzione alimentare.
In riferimento a numerosi studi empirici sul tema degli alimenti funzionali, il lavoro si è orientato su questa categoria di alimenti con particolare attenzione ai prodotti da forno realizzati nell ambito del progetto di ricerca multidisciplinare dal titolo Alimenti Funzionali e integratori nutraceutici a base di lupino bianco e derivati di agrumi - ALI.FU.I.DE.A. finanziato dalla linea di intervento 4.1.1.1 del PO FESR Sicilia 2007-2013 in cui era prevista la produzione di un biscotto con caratteristiche funzionali a base di lupino e fibra di arancia attualmente non presente nel mercato.
Gli obiettivi principali di questo studio avevano due finalità: in primo luogo individuare le variabili che condizionano il consumatore sulle scelte di acquisto di prodotti alimentari funzionali; successivamente stimare la disponibilità a pagare per un biscotto con caratteristiche funzionali rispetto ad un biscotto convenzionale già presente nel mercato.
Le indagini condotte hanno fornito un ampio patrimonio di informazioni allo scopo di valorizzare e ottenere dati utili a comprendere e interpretare il profilo del consumatore, i valori alimentari configurati come le motivazioni individuo-specifiche che regolano le scelte di acquisto e la disponibilità a pagare un prodotto alimentare funzionale.
In base alle informazioni derivanti da queste indagini sono state formulate delle valutazioni conclusive che permettono di riassumere i principali risultati e di sviluppare future ricerche focalizzate ai comportamenti dei consumatori verso gli alimenti funzionali