1,355,431 research outputs found
Computational Experience with a SDP-Based Algorithm for Maximum Cut with Limited Unbalance
No full textIn the Maximum Cut with Limited Unbalance problem, we want to partition the vertices of a weighted graph into two sets of sizes differing at most by a given threshold B, so that the sum of the weights of the crossing edges is maximum. This problem has been introduced in [Galbiati and Maffioli, Theor Comput Sci 385 (2007), 78–87] where polynomial time randomized approximation algorithms are proposed and their performance guarantees are analyzed in the case of non-negative integer weights. In this article, we present extensive computational experience with these algorithms on a large number of different graphs. We then extend the analysis of these algorithms to integer weights not restricted in sign, and continue the computational testing. It turns out that the approximation ratios obtained are always substantially better than those guaranteed by the theoretical analysis
Solution of the cumulative assignment problem with a well-structured tabu search method
No full textThe Cumulative Assignment Problem is an NP-complete problemobtained by substituting the linear objective function of the classicLinear Assignment Problem, with a non-linear cumulative function.In this paper we present a first attempt to solve the Cumulative Assignment Problem with metaheuristic techniques.In particular we consider two standard techniques, namely the Simulated Annealing and the Multi-Start methods, and we describe the eXploring Tabu Search: a new structured Tabu Search algorithm which uses an iterative multi-level approach to improve the search.The new method is analyzed through extensive computational experiments and proves to be more effective than the standard methods
La memoria come strumento di lotta: dall’incontro con Annie Ernaux
No full textIn October 2022, a few weeks after the announcement of the Nobel Prize, Annie Ernaux premiered in Italy her first film, Les Années Super8, released with her son David Ernaux-Briot. The extract below corresponds to a part of the dialogue between the French author and Francesca Maffioli, which took place in Bologna at Salaborsa Library during the XV edition of Archivio Aperto, the festival of Home Movies – National Family Film Archive
A Micro‐econometric Analysis of Public Support to Private R&D in Argentina
No full textAbstract This paper investigates the relationship between government interventions to promote investments in innovation and firm‐financed R&D. Merging a unique panel data set on Argentinean firms in the 1990s with a data base on different types of public support received through the FONTAR (Fondo Tecnólogico Argentino) program, we estimate a fixed effects model and find evidence of a significant positive impact of FONTAR on private R&D. A 1 per cent increase in the amount received through FONTAR induces an average increase of 547.6 real pesos in annual R&D expenditures. The result is robust to the use of an instrumental variable estimator that controls for the potential bias induced by changes in the structure of the program. An analysis by type of financial support reveals that the impact is mainly due to targeted and fiscal credit with no evidence that funding received through matching grants has an additionality effect on private investments. This result is in line with the predictions of a simple theoretical model that investigates the impact of different policy interventions to promote investments in R&D. When firms’ preferences are not directly observable, the provision of direct subsidies is more likely to incur the risk of adverse selection attracting firms that would have invested in innovation even in the absence of public support or dismiss some of the non‐financed projects, thus leaving unchanged or decreasing the overall level of expenditures in R&D.Innovation and R&D, policy evaluation, panel data, O32, O38, C23,
The impact of funding on research collaboration: Evidence from a developing country
No full textIn this paper we evaluate the impact of research grants on the amount of collaboration among scientific researchers in Argentina. We find a positive and significant impact of funding on collaboration which is measured in terms of the number of co-authors for publications in peer-reviewed journals. Our identification strategy is based on comparing collaboration indicators for researchers with financially supported projects with those of a control group of researchers who submitted projects that were accepted in terms
of quality, but not supported because of shortage of funds. We obtain consistent results by using different non-experimental techniques including difference-in-differences models combined with propensity score matching algorithms
La cooperazione industriale e i processi di internazionalizzazione: un’analisi critica del programma Al-Invest
No full textGli investimenti diretti italiani in Argentina: il settore degli autoveicoli e della componentistica per auto
No full textA Lagrangean Heuristic for Prize Collecting Travelling Salesman Problem
No full textIn this paper we consider the Prize Collecting Travelling Salesman Problem (PCTSP), that is a variant of the Travelling Salesman Problem (TSP) where a tour visiting each node at most once in a given graph has to be computed, such that a prize is associated with each node and a penalty has to be paid for every unvisited node; moreover, a knapsack constraint guarantees that a sufficiently large prize is collected. We develop a Lagrangean heuristic and obtain an upper bound in the form of a feasible solution starting from a lower bound to the problem recently proposed in the literature. We evaluate these bounds utilizing both randomly generated instances and real ones with very satisfactory results
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