Search results for " programmi"
showing 10 items of 1629 documents
Visua 0.1 Beta
2013
Un comando di Stata può essere digitato tramite tastiera oppure lanciato da una finestra di dialogo, il cui scopo finale è quello di preparare la stringa del comando da eseguire. Le finestre di dialogo evitano di dover ricordare la sintassi dei comandi e di commettere errori nella loro digitazione. Tutti i comandi disponibili al momento dell’installazione di Stata, salvo rare eccezioni, dispongono di una relativa finestra di dialogo. Stata mette a disposizione un linguaggio di programmazione (dialog programming language) per la creazione delle finestre di dialogo. Nonostante la sua utilità, questo linguaggio di programmazione sembra essere poco utilizzato dagli utilizzatori di Stata e, infa…
Solving some optimal control problems using the barrier penalty function method
2005
In this paper we present a new approach to solve the two-level optimization problem arising from an approximation by means of the finite element method of optimal control problems governed by unilateral boundary value problems. The minimized functional depends on control variables and state variables x. The latter are the optimal solution of an auxiliary quadratic programming problem, whose parameters depend on u.
A penalized approach for the bivariate ordered logistic model with applications to social and medical data
2018
Bivariate ordered logistic models (BOLMs) are appealing to jointly model the marginal distribution of two ordered responses and their association, given a set of covariates. When the number of categories of the responses increases, the number of global odds ratios to be estimated also increases, and estimation gets problematic. In this work we propose a non-parametric approach for the maximum likelihood (ML) estimation of a BOLM, wherein penalties to the differences between adjacent row and column effects are applied. Our proposal is then compared to the Goodman and Dale models. Some simulation results as well as analyses of two real data sets are presented and discussed.
Expert-based versus citation-based ranking of scholarly and scientific publication channels
2016
Abstract The Finnish publication channel quality ranking system was established in 2010. The system is expert-based, where separate panels decide and update the rankings of a set of publications channels allocated to them. The aggregated rankings have a notable role in the allocation of public resources into universities. The purpose of this article is to analyze this national ranking system. The analysis is mainly based on two publicly available databases containing the publication source information and the actual national publication activity information. Using citation-based indicators and other available information with association rule mining, decision trees, and confusion matrices, …
Vector coherent states and intertwining operators
2009
In this paper we discuss a general strategy to construct vector coherent states of the Gazeau-Klauder type and we use them to built up examples of isospectral hamiltonians. For that we use a general strategy recently proposed by the author and which extends well known facts on intertwining operators. We also discuss the possibility of constructing non-isospectral hamiltonians with related eigenstates.
Algorithms and tools for protein-protein interaction networks clustering, with a special focus on population-based stochastic methods
2014
Abstract Motivation: Protein–protein interaction (PPI) networks are powerful models to represent the pairwise protein interactions of the organisms. Clustering PPI networks can be useful for isolating groups of interacting proteins that participate in the same biological processes or that perform together specific biological functions. Evolutionary orthologies can be inferred this way, as well as functions and properties of yet uncharacterized proteins. Results: We present an overview of the main state-of-the-art clustering methods that have been applied to PPI networks over the past decade. We distinguish five specific categories of approaches, describe and compare their main features and …
A multi-local optimization algorithm
1998
The development of efficient algorithms that provide all the local minima of a function is crucial to solve certain subproblems in many optimization methods. A “multi-local” optimization procedure using inexact line searches is presented, and numerical experiments are also reported. An application of the method to a semi-infinite programming procedure is included.
Spatio-temporal modelling of COVID-19 incident cases using Richards’ curve: An application to the Italian regions
2021
Abstract We introduce an extended generalised logistic growth model for discrete outcomes, in which spatial and temporal dependence are dealt with the specification of a network structure within an Auto-Regressive approach. A major challenge concerns the specification of the network structure, crucial to consistently estimate the canonical parameters of the generalised logistic curve, e.g. peak time and height. We compared a network based on geographic proximity and one built on historical data of transport exchanges between regions. Parameters are estimated under the Bayesian framework, using Stan probabilistic programming language. The proposed approach is motivated by the analysis of bot…
Cotas inferiores para el QAP-Arbol
1985
The Tree-QAP is a special case of the Quadratic Assignment Problem where the flows not equal zero form a tree. No condition is required for the distance matrix. In this paper we present an integer programming formulation for the Tree-QAP. We use this formulation to construct four Lagrangean relaxations that produce several lower bounds for this problem. To solve one of the relaxed problems we present a Dynamic Programming algorithm which is a generalization of the algorithm of this type that gives a lower bound for the Travelling Salesman Problem. A comparison is given between the lower bounds obtained by each ralaxation for examples with size from 12 to 25.
Combining the intensity and sequencing of the poverty experience:a class of longitudinal poverty indices
2011
Summary Traditional measures of the persistence of poverty do not devote enough attention to the sequence of spells of poverty. We propose a new class of indices which measures the severity of chronic poverty, taking into account the way in which spells of poverty and non-poverty follow one another along individual life courses. All the years spent in poverty concur with the measurement of the persistency of poverty, albeit with a decreasing contribution provided that the distance between two consecutive spells of poverty becomes longer. Moreover, the distance from the poverty line and the poverty persistence probabilities are explicitly taken into account. A macrolevel index, which allows …