Search results for " Mathematics"
showing 10 items of 10797 documents
Compound conditionals as random quantities and Boolean algebras
2022
Conditionals play a key role in different areas of logic and probabilistic reasoning, and they have been studied and formalised from different angles. In this paper we focus on the de Finetti's notion of conditional as a three-valued object, with betting-based semantics, and its related approach as random quantity as mainly developed by two of the authors. Compound conditionals have been studied in the literature, but not in full generality. In this paper we provide a natural procedure to explicitly attach conditional random quantities to arbitrary compound conditionals that also allows us to compute their previsions. By studying the properties of these random quantities, we show that, in f…
Financial contagion through space-time point processes
2020
AbstractWe propose to study the dynamics of financial contagion by means of a class of point process models employed in the modeling of seismic contagion. The proposal extends network models, recently introduced to model financial contagion, in a space-time point process perspective. The extension helps to improve the assessment of credit risk of an institution, taking into account contagion spillover effects.
INTEREST OF LATVIAN AND LITHUANIAN STUDENTS IN SCIENCE AND MATHEMATICS
2018
Interest is one of the most important components for a successful teaching/learning process; unfortunately, nowadays students’ interest in science and mathematics is decreasing. The aim of the research is to explore the cognitive interest of 15-year- old students in science and mathematics. Students in Latvia and Lithuania participated in the survey; the data show that students’ cognitive interest in this area in both countries is mediocre. The factor analysis was used to single out four main dimensions of the cognitive interest – interest in the context, interest in mathematics, inquiry interest and enthusiasm. Students’ interest is higher in issues connected with practical life, the solut…
Eye-tracking revision processes of translation students and professional translators
2019
Great effort has been made to define and to measure revision competence in translation. However, combined eye tracking and keylogging have hardly been applied in revision research. We believe it is...
A Note on Laws of Motion for Aggregate Distributions
2020
I derive the law of motion for the aggregate distribution directly from the laws of motion for the individuals’ states. By relying on concepts from measure theory, the derivation is concise and intuitive. I address random shocks both at the micro level and at the macro level. Micro-level shocks completely cancel at the aggregate level provided that a law of large numbers applies. Therefore, the law of motion for the aggregate distribution is a deterministic process in the absence of macro-level uncertainty. If there are macro-level risks, the law of motion for the aggregate distribution exhibits a stochastic component additionally. I illustrate the formalism in a model of wealth accumulatio…
A continuous time tug-of-war game for parabolic $p(x,t)$-Laplace type equations
2019
We formulate a stochastic differential game in continuous time that represents the unique viscosity solution to a terminal value problem for a parabolic partial differential equation involving the normalized $p(x,t)$-Laplace operator. Our game is formulated in a way that covers the full range $1<p(x,t)<\infty$. Furthermore, we prove the uniqueness of viscosity solutions to our equation in the whole space under suitable assumptions.
Operational and financial performance of Italian airport companies: A dynamic graphical model
2016
Abstract This paper provides evidence on the relationship within a set of financial and operational indicators for Italian airports over 2008–2014. The limited sample size of national and regional airports suggests to apply the penalised RCON ( V , E ) model, which falls within the class of Gaussian graphical models. It provides both estimate and easy way to visualise conditional independence structures of the variables. Moreover, it is particularly suitable for handling longitudinal data where small number of units and huge number of variables have been collected. Findings highlight that a qualified concept of size matters in determining good financial performance. Specifically, increasing…
GIS Infomobility for Travellers
2016
Geographical Information Systems (GIS) are essential systems to support decisions on territorial and environmental aspects. But they not always have been properly used for this purpose. Only in recent years GIS have been getting better used for the planning, management and control of the territory. The application of GIS to the transport sector has become relevant both for management and decision-making in support of Public Administration (PA) and citizens. GIS are particularly useful for roads and routing graphs management capabilities as well as for searching the most suitable path. The results achieved in this research activity aimed to evaluate different road graphs, proprietary and fre…
A stochastic dynamical social model involving a human happiness index
2018
[EN] This paper presents a new human happiness index built through five dimensions: development, freedom, solidarity, justice and peace. These five dimensions are evaluated through quantitative variables obtained from the Human Development Reports, World Data Bank and Eurostat. The new happiness index has been built following the guidelines set by the Human Development Reports of the UN for the construction of quality indices, and it has been compared on a set of 13 EU countries with the Overall Life Satisfaction Index, which is used by the UN. Moreover, the new index has been included in a dynamic mathematical model through the demographic rates to study the evolution of the population. Th…
Probabilistic cross-validation estimators for Gaussian process regression
2018
Gaussian Processes (GPs) are state-of-the-art tools for regression. Inference of GP hyperparameters is typically done by maximizing the marginal log-likelihood (ML). If the data truly follows the GP model, using the ML approach is optimal and computationally efficient. Unfortunately very often this is not case and suboptimal results are obtained in terms of prediction error. Alternative procedures such as cross-validation (CV) schemes are often employed instead, but they usually incur in high computational costs. We propose a probabilistic version of CV (PCV) based on two different model pieces in order to reduce the dependence on a specific model choice. PCV presents the benefits from both…