Neural Networks to Determine the Relationships Between Business Innovation and Gender Aspects

2021

Gender aspects of management, innovation and entrepreneurship are gaining more and more importance as cross-cutting issues for researchers, practitioners and decision makers. Extant literature pays a growing attention to the hypothesis that there exists a correlation between the gender diversity of corporate boards of directors and the business attitude to innovation. In this paper we introduce a working framework to test the aforementioned hypothesis and to examine the correlation between board diversity and innovation perception of a business. This framework is based on correlation computation and feed-forward neural networks, and it is used to evaluate whether the gender component may be…

Sustainable Management of Tourist Flow Networks: A Mean Field Model

2023

In this article, we propose a mean field game approach for modeling the flows of excursionists within a network of tourist attractions. We prove the existence of an equilibrium within the network using a balance ordinary differential equation together with optimality conditions in terms of the value function. We also propose a bi-level formulation of the problem where we aim at achieving a sustainable-oriented control strategy in the upper level and at maximizing excursionists’ satisfaction in the lower level. Our proposed model may provide an effective management tool for local authorities who deal with the challenging problem of finding an optimal control policy to the often conflicting o…

A computational proposal for a robust estimation of the Pareto tail index: An application to emerging markets

2022

Abstract In this work, we backtest and compare, under the VaR risk measure, the fitting performances of three classes of density distributions (Gaussian, Stable and Pareto) with respect to three different types of emerging markets: Egypt, Qatar and Mexico. We also propose a new technique for the estimation of the Pareto tail index by means of the Threshold Accepting (TAVaR) and the Hybrid Particle Swarm Optimization algorithm (H-PSOVaR). Furthermore, we test the accuracy and robustness of our estimates demonstrating the effectiveness of the proposed approach.

Su di una classe di matrici

2003

Nella presente nota si definiscono le matrici pseudoinvolutorie, se ne studiano le proprietà ed analogie, si generalizzano i risultati.

A heuristic fuzzy algorithm for assessing and managing tourism sustainability

2019

“Smartness” and “sustainability” are gaining growing attention from both practitioners and policy makers. “Smartness” and “sustainability” assessments are of crucial importance for directing, in a systemic perspective, the decision-making process toward sustainability and smart growth objectives. Sustainability assessment is a major challenge due to the multidisciplinary aspects involved that make the evaluation process complex and hinder the effectiveness of available monitoring tools. To achieve the assessment objective, we introduce an enhanced fuzzy logic-based framework for handling the inherent uncertainty and vagueness of the involved variables: we apply our approach to Italy, and we…

Selezione di Portafoglio e Metaeuristiche

2013

Il problema della selezione del portafoglio (PSP) ha come obiettivo quello di determinare, disponendo di un dato insieme di titoli, il portafoglio che minimizza una misura di rischio per un dato livello di rendimento minimo richiesto. Sebbene nella sua formulazione originaria il PSP può essere risolto utilizzando algoritmi di programmazione lineare o quadratica, l'inclusione di ulteriori vincoli ed obiettivi rende il problema computazionalmente difficile. Nel presente lavoro viene proposto un approccio metaeuristico al PSP in cui vengono considerate diverse misure di distanza tra i portafogli della frontiera efficiente (Mean-Variance) ed il portafoglio ottimo che si ottiene in corrispondenz…

An Empirical Investigation of Heavy Tails in Emerging Markets and Robust Estimation of the Pareto Tail Index

2021

In this work we analyze and compare the performances of VaR-based estimatorswith respect to three different classes of distributions, i.e., Gaussian, Stable and Pareto, and to different emerging markets, i.e., Egypt, Qatar and Mexico. This is motivated by the evidence that there are points of distinction between emerging and developed markets mainly relating to the speed and reliability of information available to investors.We propose a computational Threshold Accepting-VaR based algorithm (TAVaR) for optimally estimating the Pareto tail index. A Monte Carlo bias estimation analysis is also carried out by comparing our proposed methodology with the Hill estimator and a variant of it.

Un approccio nello state space di un problema di controllo finanziario

2004

Nell'ambito dei metodi di sintesi che si prefiggono l’obbiettivo di ottenere un sistema a ciclo chiuso con la desiderata distribuzione di autovalori della matrice dinamica (per la nota relazione che esiste tra detti autovalori ed i modi del sistema) nel presente lavoro si propone un procedimento di sintesi applicato ad un problema di portafoglio, al fine di evidenziare l’efficacia di tali strumenti d’indagine anche in ambito finanziario.

A fuzzy evaluation of tourism sustainability

2019

For many years the sustainability assessment of tourist destinations has been based on the carrying capacity, which is a measure that takes into account the preservation of a geographical area (by measuring the number of tourists, the visitor flow and the environmental thresholds) along with its tourist fruition (by assessing the quality of the experience perceived by visitors). Unfortunately, its definition lacks clarity, and its dependence upon qualitative variables makes it unable to provide a unique criterion for its assessment. In this paper we propose a fuzzy approach that takes into account the inherent uncertainty and vagueness of the involved variables to assess a destination’s sus…

Detection of local tourism systems by threshold accepting

2015

Despite the importance of tourism as a leading industry in the development of a country’s economy, there is a lack of criteria and methodologies for the detection, promotion, and governance of local tourism systems. We propose a quantitative approach for the detection of local tourism systems the size of which is optimal with respect to geographical, economic, and demographical criteria: we formulate the problem as an optimisation problem and we solve it by a metaheuristic approach; then we compare the obtained results with standard clustering approaches and with an exact optimisation solver. Results show that our approach requires low computational times to provide results that are better …

The Problem of Time Arrow in Financial Time Series

According to the efficient market hypothesis, future movements of the market cannot be predicted. This introduces an intrinsic time asymmetry of the financial time series as there are no laws forbidding “predicting” past based on the current market fluctuations. This clear time asymmetry in the basic laws of finance raises a question which we shall be referring to as the problem of time arrow: are there any noticeable statistical differences between forward-in-time and reverse-in-time market data. Majority of the statistical methods used for financial time series are time-symmetric and hence, not usable for our purposes. The first method used in our study is the analysis of the length-distr…

Sustainability and tourist flow networks: a mean field bi-level optimization approach

The widespread acknowledgement of tourism as a strategic pillar for economic growth and development has boosted competitiveness among tourist destinations. This concept has been greatly emphasized during the current COVID-19 pandemic crisis. Nevertheless, the massive presence of tourists imposes the challenge of adopting sustainable tourism practices to balance economic prosperity opportunities with potential threats to the environment and local communities. There are many definitions for sustainability, but the most effective one is ``the capacity to endure'' [Emel et al, 1997]: from an economic perspective this leads to find an equilibrium between short and long-term objectives so that to…

A methodology and algorithms for an optimal identification of Tourist Local Systems

2007

In last years, despite the emphasis on the importance of tourism as a leading industry in the development of a country’s economy, there is a lack of criteria and methodologies for the identification, the promotion and the governance of Tourism Local Systems (TLS). Moreover, nowadays an important debate is more and more emerging on the sustainable tourism development which involve three interconnected aspects: environmental, socio-cultural and economic. To this end, in this paper, a rigorous mathematical model is proposed for the optimal identification and dimensioning of TLS. The model here presented consists of a two stage methodology: at first, all the factors that characterize a geograph…

Gender analysis and attention to gender: An experimental framework

Gender aspects are gaining more and more attention for policy makers, practitioners and faculties. They also have a great importance for funding purposes, since many calls for proposals by national and international agencies require a gender plan and/or an analysis of the gender aspect, especially referring to the extent to which a candidate research project affects differently men and women. In this context, we want to understand whether there exists a relationship between the gender diversity of corporate boards of directors and the way a business articulates gender aspects on their corporate communications and activities on the Internet. To achieve this goal, we created a set of meaningf…

The predictive power of power-laws: An empirical time-arrow based investigation

2022

The efficient market hypothesis forbids any predictability towards future, but there is no such restriction in the case of reversed-looking approaches. We analyze if this asymmetry in non-predictability is reflected in the statistical features of financial time series. Our study is based on the analysis of the length-distribution of periods with high variability, and introduces time-asymmetric modifications of the method which are capable of revealing differences of the time series in forward and reversed time. We show that the future and reversed-looking time-series possess very similar properties, with some features being distinguishable with our method. Our findings give also evidence of…

Clustering local tourism systems by threshold acceptance

2015

Despite the importance of tourism as a leading industry in the development of a country’s economy, there is a lack of criteria and methodologies for the detection, promotion and governance of local tourism systems. We propose a quantitative approach for the detection of local tourism systems that are optimal with respect to geographical, economic, and demographical criteria. To this end, we formulate the issue as an optimization problem, and we solve it by means of Threshold Acceptance, a meta-heuristic algorithm which does not require us to predefine the number of clusters and also does not require all geographic areas to belong to a cluster.

Sul ruolo dei sistemi di supporto alle decisioni nelle attività finanziarie. Un'applicazione per la gestione del portafoglio prestiti

2004

I contributi metodologici che sono stati espressi nello studio dei processi decisionali, nonché gli straordinari risultati conseguiti sui meccanismi di acquisizione ed elaborazione della conoscenza, hanno consentito lo sviluppo di molteplici prodotti software, rivolti ad aiutare e/o sostituire l'uomo nell'attività di individuazione, analisi, valutazione e selezione di alternative nel contesto di processi decisionali complessi e mal strutturati. Tuttavia, molti di questi prodotti non hanno superato la fase sperimentale e prototipale; ne consegue la necessita' di strumenti computazionali innovativi che sappiano rappresentare in modo più appropriato il processo dinamico di adattamento e di cam…

CLUSTERING TOURIST LOCAL SYSTEMS BY VERTEX PARTITIONING AND LOCAL SEARCH

2014

Nonostante l’industria del turismo venga riconosciuta come un settore trainante per l’intera economia di un Paese, a tutt’oggi si registra una mancanza di criteri e metodologie ai fini della localizzazione, promozione e gestione di un Sistema Turistico Locale (STL). A tal fine, nel presente lavoro viene proposto un approccio di tipo quantitativo al problema sia della localizzazione che del dimensionamento ottimale di un STL tenendo conto di criteri e/o vincoli di natura geografica, economica e demografica. Il problema di ottimizzazione è rappresentato su grafo ed è risolto ricorrendo all’algoritmo di ricerca locale di Threshold Accepting (TA). Despite the importance of tourism as a leading …

Fuzzy Multi-Criteria Decision Making: An entropy-based approach to assess tourism sustainability

2019

In this article, we propose a method for ranking tourist destinations and evaluating their performances under a sustainability perspective: a fuzzy multiple criteria decision-making method is applied for determining sustainability performance values and ranking destinations accordingly. We select a set of sustainability evaluation criteria and use a fuzzy analytic hierarchy process to weight the selected criteria. We also optimize each evaluator’s membership function support by means of a fuzzy entropy maximization criteria. A case study is illustrated and results are compared with two data envelopment analysis–based models. The simplicity of the proposed approach along with the easy reada…

Una metodologia per la suddivisione di un'area geografica regionale in Sistemi Turistici Locali.

2005

In questo lavoro si propone un metodo per a®rontare e risolvere il problema del dimensionamento e della localizzazione ottimali dei Sistemi Turistici Locali. A tal ¯ne, l'applicazione del modello proposto sull'area territoriale in esame viene iservata ad una fase in cui sono stati giµa presi in considerazione opzioni e vincoli trategici; viene presentato, invero, un criterio per la de¯nizione della gerarchia delle unitµa territoriali, che consente, d'altra parte, una sensibile riduzione delle alterna- ive ammissibili nella de¯nizione dei sistemi turistici, che avviene proponendo uno peci¯co algoritmo. l problema di ottimizzazione µe risolto successivamente mediante un procedimento di ricerc…

Propagation of Bankruptcy Risk over Scale-Free Economic Networks.

2022

The propagation of bankruptcy-induced shocks across domestic and global economies is sometimes very dramatic; this phenomenon can be modelled as a dynamical process in economic networks. Economic networks are usually scale-free, and scale-free networks are known to be vulnerable with respect to targeted attacks, i.e., attacks directed towards the biggest nodes of the network. Here we address the following question: to what extent does the scale-free nature of economic networks and the vulnerability of the biggest nodes affect the propagation of economic shocks? We model the dynamics of bankruptcies as the propagation of financial contagion across the banking sector over a scale-free network…

Distance Measures for Portfolio Selection

2017

The classical Markowitz approach to the portfolio selection problem (PSP) consists of selecting the portfolio that minimises the return variance for a given level of expected return. By solving the problem for different values of this expected return we obtain the Pareto efficient frontier, which is composed of non-dominated portfolios. The final user has to discriminate amongst these points by resorting to an external criterion in order to decide which portfolio to invest in. We propose to define an external portfolio that corresponds to a desired criterion, and to assess its distance from the Markowitz frontier in market allowing for short-sellings or not. We show that this distance is ab…

Un modello fuzzy di valutazione della sostenibilità applicato al turismo

2004

Negli ultimi decenni molti sistemi turistici hanno conosciuto (spesso subendoli passivamente) periodi di forti cambiamenti strutturali, che hanno prodotto una riallocazione delle risorse economiche e naturali, nonch´e una variazione nella loro destinazione d’uso, rendendo pi`u complesso il rapporto uomo-ambiente. Sorvolando gli aspetti definitori, nonch´e le difficolt`a operative inerenti alla sostenibilit` a nel turismo, consapevoli che questa non `e una cosa che possa riguardare isolatamente un solo settore, nel presente lavoro si propone un modello che consenta di valutare in modo semplice ed efficace il grado di sostenibilit`a di un’area geografi- ca. Ci`o si ottiene utilizzando la logi…