Penalized likelihood inference in extreme value analyses

Models for extreme values are usually based on detailed asymptotic argument, for which strong ergodic assumptions such as stationarity, or prescribed perturbations from stationarity, are required. In most applications of extreme value modelling such assumptions are not satisfied, but the type of departure from stationarity is either unknown or complex, making asymptotic calculations unfeasible. This has led to various approaches in which standard extreme value models are used as building blocks for conditional or local behaviour of processes, with more general statistical techniques being used at the modelling stage to handle the non-stationarity. This paper presents another approach in this direction based on penalized likelihood. There are some advantages to this particular approach: the method has a simple interpretation; computations for estimation are relatively straightforward using standard algorithms; and a simple reinterpretation of the model enables broader inferences, such as confidence intervals, to be obtained using MCMC methodology. Methodological details together with applications to both athletics and environmental data are given.     

EXTERNAL AIDS FOR SOCIAL MEMORY

Collective or social memories are not just a way for accumulating and preserving but also for sharing and developing knowledge. Indeed, as knowledge is made explicit and elaborated by a community, it enriches the local culture and the current practices, becoming a basis for communication and learning. This paper addresses the concept of 'social memory' in a specific 'community of practice': teachers and students of primary schools. The work is developed within HIPS1 (Hyper Interaction within Physical Space), a three-year (1997-2000) research project funded by the European Commission within the I 3 (I-Cube) Programme. HIPS is a hand-held location-aware tourist guide that delivers information related to the surrounding space mainly reacting to the physical movements of visitors (Benelli et al . 1999). The guide is designed to minimize the boundary between the physical space and the related information through a number of situated and contextual-aware interaction mechanisms. In the paper we present a specific application of HIPS as tool to support the creation of a social memory. First, we illustrate the theoretical framework, the cultural psychology (Vygotsky 1978), which we adopted to design the tool as an external aid for social memory. Afterwards we describe the user study and the design process that resulted in the development of an early prototype. The conclusions are a reflection about the use of new technology to open new learning opportunities for students.     

OIL AND THE MACROECONOMY: A QUANTITATIVE STRUCTURAL ANALYSIS

We model an open economy where macroeconomic variables fluctuate in response to oil supply shocks, as well as aggregate demand and supply shocks generated domestically and abroad. We use several robust predictions of the model to identify five fundamental shocks underlying the fluctuations of the (real) oil price, the US activity and the global business cycle. The estimates show that supply shocks generated in the global economy explain the largest fraction of the oil price fluctuations, about four times more than canonical oil supply shocks. The correlation between oil prices and the US activity varies with the type of shock.     

Suspect community or suspect category? The impact of counter-terrorism as ‘policed multiculturalism’

How to think about the impact of counter-terrorism and counter-radicalisation on ethnic and religious accommodation? Much of the literature draws on the concept of ‘suspect community’, suggesting it has primarily alienated the Muslim community, favouring an assimilationist model of ‘muscular liberalism’. In this article, while I consider the merits of the ‘suspect community’ hypothesis, I argue that it only partially accounts for the effects of counter-terrorism and counter-radicalisation on multicultural societies. I contend that much of the literature has focused too narrowly on the discriminatory effects of counter-terrorist policies and has been unable to grasp the more insidious political effects of counter-terrorism policies based on the active participation and involvement of Muslims in their own policing. The main hypothesis of this paper is that rather than promoting ‘assimilation’, as the government would expect, or alienation, as the advocates of the ‘suspect community’ hypothesis would contend, counter-terrorist policies produce and reinforce a government of society in discrete and divided ethno-religious groups. Such ‘policed multiculturalism’—understood as the recognition and the management of diversity through a security perspective—has an important consequence in that it removes fundamental questions about pluralism from political debate, casting them instead in a depoliticised language of security.     

A note on the decidability of de Finetti's coherence

To check the de Finetti coherence of a putative probability assigned to a classA of events, we must know the possible combinations of truth values (constituents) of any finite class of events inA. Even for a very simple, finite,A this can be impossible. In this case the notion of DF coherence cannot be applied to some or all the putative probabilities on this class of events.     

Decomposition by subpopulations of the Zenga-84 inequality curve and the related index $$\zeta $$: an application to 2014 Bank of Italy survey

Statistical Methods & Applications - This paper describes an innovative procedure to decompose by subpopulations the values assumed by the Zenga-84 inequality curve Z(p). This decomposition...     

A multiple buyer – supplier relationship in the context of SMEs’ digital supply chain management*

Abstract

By underlining the relevance of the use of ICTs, knowledge sharing and electronic markets for SMEs, it emerges the need for stimulating a debate on digitisation process of supply chain management (SCM). Electronic infrastructure in the service sector are reducing each kind of cost and improving multiply buyer–supplier relationships, facilitating negotiations and transactions. However, since the coordination costs are still high, the use of ICTs is limited. This phenomenon thus attracts the interests of scholars and practitioners. Although it still needs to further investigate. Especially, the optimal use of ICTs within SMEs’ SCM have not been studied yet. Therefore, by leveraging on four proxies: ICTs specialised human resources, knowledge sharing activities, buyer–supplier relationships, adoption of electronic markets this optimal was analysed via structural equation modelling based on a sample of 1254 SMEs operating in the service sector in Italy.     

Combining Linear and Non-Linear Objectives in Spanning Tree Problems

A classical approach to multicriteria problems asks for the optimization of a suitable linear combination of the objectives. In this work we address such problems when one of the objectives is the linear function, the other is a non-linear one and we seek for a spanning tree of a given graph which optimizes the combination of the two functions. We consider both maximization and minimization problems and present the complexity status of 56 such problems, giving, whenever possible, polynomial solution algorithms.     

The Impact of Income and Employment Status on Leaving Home: Evidence from the Italian ECHP Sample

In this paper we investigate the role economic resources play in the decision of young Italian adults to leave the parental home. This is of particular interest given that, in Italy, young people leave home considerably later than in other European countries. We use the first two waves of the Italian sample of the European Community Household Panel. We use a Heckman selection‐type probit procedure to account for left censoring and unobserved heterogeneity. We find that economic circumstances are important. In particular, we find personal income resources, as well as parental income levels, to be crucial in leaving home. Our results suggest that stable employment is an important prerequisite for men to start their own household. For women, on the other hand, finding a partner seems to the most important factor in becoming independent of their parents.