Ferraris G.,Collegio carlo Alberto
JASSS | Year: 2011
The paper elaborates the notion of innovation as an emerging property of complex system dynamics and presents an agent-based simulation model (ABM) of an economy where systemic knowledge interactions among heterogeneous agents are crucial for the recombinant generation of new technological knowledge and the introduction of innovations. In this approach the organization of the system plays a crucial role in assessing the chances of individual firms to actually introduce innovations because it qualifies the access to external knowledge, an indispensable input, together with internal learning and research activities, into the recombinant generation of new knowledge. The introduction of innovations is analyzed as the result of systemic knowledge interactions among myopic agents that are credited with an extended procedural rationality that includes forms of creative reaction. The creative reaction of agents may lead to the introduction of productivity enhancing innovations. This takes place only when the structural, organizational and institutional characteristics of the system are such that agents, reacting to out-of-equilibrium conditions, can actually take advantage of external knowledge available within the innovation system into which they are embedded to generate new technological knowledge. The ABM enables one to explore effects of alternative organizational features of the systems, namely different configurations of the intellectual property right regimes and different architectural configurations of the regional structure into which knowledge interactions take place, on the rates of introduction of technological innovations. The results of the ABM suggest that the dissemination of knowledge favors the emergence of creative reactions and hence faster rates of introduction of technological innovations.
Malago L.,University of Milan |
Matteucci M.,Polytechnic of Milan |
Pistone G.,Collegio Carlo Alberto
2013 IEEE Congress on Evolutionary Computation, CEC 2013 | Year: 2013
The geometric framework based on Stochastic Relaxation allows to describe from a common perspective different model-based optimization algorithms that make use of statistical models to guide the search for the optimum. In this paper Stochastic Relaxation is used to provide theoretical results on Estimation of Distribution Algorithms (EDAs). By the use of Stochastic Relaxation we show how the estimation of the fitness model by least squares linear regression corresponds to the estimation of the natural gradient. This equivalence allows to simultaneously perform model selection and robust estimation of the natural gradient. Finally, we interpet Linear Programming relaxation as an example of Stochastic Relaxation, with respect to the regular gradient. © 2013 IEEE.
Malago L.,Polytechnic of Milan |
Matteucci M.,Polytechnic of Milan |
Pistone G.,Collegio Carlo Alberto
FOGA'11 - Proceedings of the 2011 ACM/SIGEVO Foundations of Genetic Algorithms XI | Year: 2011
In this paper we present a geometrical framework for the analysis of Estimation of Distribution Algorithms (EDAs) based on the exponential family. From a theoretical point of view, an EDA can be modeled as a sequence of densities in a statistical model that converges towards distributions with reduced support. Under this framework, at each iteration the empirical mean of the fitness function decreases in probability, until convergence of the population. This is the context of stochastic relaxation, i.e., the idea of looking for the minima of a function by minimizing its expected value over a set of probability densities. Our main interest is in the study of the gradient of the expected value of the function to be minimized, and in particular on how its landscape changes according to the fitness function and the statistical model used in the relaxation. After introducing some properties of the exponential family, such as the description of its topological closure and of its tangent space, we provide a characterization of the stationary points of the relaxed problem, together with a study of the minimizing sequences with reduced support. The analysis developed in the paper aims to provide a theoretical understanding of the behavior of EDAs, and in particular their ability to converge to the global minimum of the fitness function. The theoretical results of this paper, beside providing a formal framework for the analysis of EDAs, lead to the definition of a new class algorithms for binary functions optimization based on Stochastic Natural Gradient Descent (SNGD), where the estimation of the parameters of the distribution is replaced by the direct update of the model parameters by estimating the natural gradient of the expected value of the fitness function. © 2011 ACM.
Lawson C.,Collegio Carlo Alberto |
Lawson C.,University of Turin |
Lawson C.,City University London
Journal of Technology Transfer | Year: 2013
This paper provides evidence that university-industry collaboration is important for turning commercial opportunities into patents. The results suggest that researchers who receive a large share of research grants from industry have a higher propensity to file a patent. Small dissemination grants generally exert a positive effect, whether they come from industry or not. It also finds that these interactions do not increase the number of industry owned patents alone but benefit universities' commercialisation efforts in general. © 2012 Springer Science+Business Media New York.
Malago L.,Shinshu University |
Pistone G.,Collegio Carlo Alberto
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015
We discuss the optimization of the stochastic relaxation of a real-valued function, i.e., we introduce a new search space given by a statistical model and we optimize the expected value of the original function with respect to a distribution in the model. From the point of view of Information Geometry, statistical models are Riemannian manifolds of distributions endowed with the Fisher information metric, thus the stochastic relaxation can be seen as a continuous optimization problem defined over a differentiable manifold. In this paper we explore the second-order geometry of the exponential family, with applications to the multivariate Gaussian distributions, to generalize second-order optimization methods. Besides the Riemannian Hessian, we introduce the exponential and the mixture Hessians, which come from the dually flat structure of an exponential family. This allows us to obtain different Taylor formulæ according to the choice of the Hessian and of the geodesic used, and thus different approaches to the design of second-order methods, such as the Newton method. © Springer International Publishing Switzerland 2015.
Guardiancich I.,Collegio Carlo Alberto |
Natali D.,University of Bologna
Global Social Policy | Year: 2012
Over the past 40 years, the European Union (EU) has developed the most advanced system of coordination of social security rights in the world, as a corollary to the free movement of workers. Notwithstanding, problems with the acquisition, transfer and fruition of supplementary pension rights still undermine labour mobility across the member states. This article aims to describe EU pension regulation in the field and illustrates how the EU has employed two different approaches to tackle the problem. The first approach is to directly facilitate the portability of supplementary pension rights - which deeply affects national social policy. The second is to develop transnational schemes leading to a single market for occupational pensions - an exercise in market-making integration. This article explores the main problems in implementing the portability principle and puts forward tangible solutions to unblocking the situation. This sheds light on the persistent tensions between supranational regulation and national pension policy, showing the need for a holistic strategy to resolve both institutional and technical issues. © The Author(s) 2012.
Saraceno C.,Collegio Carlo Alberto
Journal of European Social Policy | Year: 2016
The aim of this article is to articulate the concepts of familialism and defamilialization as well as their indicators to assess whether and how welfare states, or regimes, differ not only in the degree to which they are defamilialized but also in the specific familialism form. In other words, it assesses whether family responsibility in a given area (and its gender dimension) is only assumed without public policy support or, on the contrary, whether it is actively enforced by laws or supported by income transfers and time allocation. The same diversification also exists for the opposite concept, defamilialization, which may happen through positive, direct or indirect policy interventions or because of the lack of such interventions, encouraging recourse to the market. The article shows that when considering these distinctions in the analyses, the profiles of countries that are usually generically described as ‘familialistic welfare states’, such as Italy and Spain in Europe or Japan and Korea in East Asia, and their similarities and differences partly differ from those that emerge when considering only a simplified familialism – defamilialization dichotomy, in so far both familialism and defamilialization may occur, and be combined, through distinct means, offering, therefore, also different options. © 2016, © The Author(s) 2016.
Hinnosaar T.,Collegio Carlo Alberto
International Journal of Industrial Organization | Year: 2016
This paper studies penny auctions, a novel auction format in which every bid increases the price by a small amount, but placing a bid is costly. Outcomes of real-life penny auctions are often surprising. Even when selling cash, the seller may obtain revenue that is much higher or lower than its nominal value, and losers in an auction sometimes pay much more than the winner. This paper characterizes all symmetric Markov-perfect equilibria of penny auctions and studies penny auctions' properties. The results show that a high variance of outcomes is a natural property of the penny auction format and high revenues are inconsistent with rational risk-neutral participants. © 2016 Elsevier B.V. All rights reserved.
O'Dwyer C.,Collegio Carlo Alberto
Journal of Aging Studies | Year: 2013
Numerous studies have indicated that a "psycho-social" person-centered care approach, involving the delivery of a compassionate, respectful model of care, leads to a high quality of life, particularly for older people living in residential care. This has prompted policy-makers to endorse this approach. Yet, some commentators have argued that the model of person-centered care in official government policies equates to a "consumer-based" rather than a psycho-social approach, as it focuses solely on offering service-users more choice and on promoting independence. However, as such arguments are made in the absence of any empirical analysis, it is unclear both whether such a distinction exists in practice, and, if so, how this alternative model developed. This study explores the development of minimum standards for residential care settings for older people in Ireland in order to address this gap in our understanding of person-centered care. Findings confirm that a consumer-driven model of person-centered care underpins the Irish Standards; residential care is portrayed as a hotel-like service and residents as discerning consumers, which may be unsuitable for older people in residential care with limited capacity to make key choices. Analysis indicates that this model can be seen both as an extension of consumer-driven policies endorsed by many neo-liberal governments, and also of policy-makers' fears of losing their autonomy when they reach the "Fourth Age". This study is particularly illuminating, given the similarities between the Irish care system with England, Scotland, Wales, Northern Ireland and Australia. © 2013 Elsevier Inc.
Pistone G.,Collegio Carlo Alberto
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2013
The differential-geometric structure of the set of positive densities on a given measure space has raised the interest of many mathematicians after the discovery by C.R. Rao of the geometric meaning of the Fisher information. Most of the research is focused on parametric statistical models. In series of papers by author and coworkers a particular version of the nonparametric case has been discussed. It consists of a minimalistic structure modeled according the theory of exponential families: given a reference density other densities are represented by the centered log likelihood which is an element of an Orlicz space. This mappings give a system of charts of a Banach manifold. It has been observed that, while the construction is natural, the practical applicability is limited by the technical difficulty to deal with such a class of Banach spaces. It has been suggested recently to replace the exponential function with other functions with similar behavior but polynomial growth at infinity in order to obtain more tractable Banach spaces, e.g. Hilbert spaces. We give first a review of our theory with special emphasis on the specific issues of the infinite dimensional setting. In a second part we discuss two specific topics, differential equations and the metric connection. The position of this line of research with respect to other approaches is briefly discussed. © 2013 Springer-Verlag.