The Importance of Being Clustered: Uncluttering the Trends of Statistics from 1970 to 2015

In this paper we retrace the recent history of statistics by analyzing all the papers published in five prestigious statistical journals since 1970, namely: Annals of Statistics, Biometrika, Journal of the American Statistical Association, Journal of the Royal Statistical Society, series B and Statistical Science. The aim is to construct a kind of "taxonomy" of the statistical papers by organizing and by clustering them in main themes. In this sense being identified in a cluster means being important enough to be uncluttered in the vast and interconnected world of the statistical research. Since the main statistical research topics naturally born, evolve or die during time, we will also develop a dynamic clustering strategy, where a group in a time period is allowed to migrate or to merge into different groups in the following one. Results show that statistics is a very dynamic and evolving science, stimulated by the rise of new research questions and types of data

La complessa soluzione istituzionale adottata in Bosnia ed Erzegovina: finalità ed effetti nel passare del tempo = The complex institutional solution adopted in Bosnia and Herzegovina: purpose and effects over time. European Diversity and Autonomy Papers EDAP 02/2019

After the collapse of socialist Yugoslav, Bosnia and Herzegovina has been the theatre of a terrible conflict, ended thanks to an international effort. This paper analyses the regulation of the form of government adopted in order to ensure the equal standing of the three constituent peoples: Serb, Croat and Bosniak, which fought each other during the civil war. This example of ‘constitutional engineering’ was finalized to favor the appeasement in the area, thus guaranteeing the survival of a multiethnic (federal) State. Over time, these mechanisms evolved into an obstacle for the correct functioning of the institutional system, making the democratic consolidation more difficult. The investigation will verify the factors that contribute to this ‘displacement’

Complexity of Timeline-Based Planning over Dense Temporal Domains: Exploring the Middle Ground

In this paper, we address complexity issues for timeline-based planning over dense temporal domains. The planning problem is modeled by means of a set of independent, but interacting, components, each one represented by a number of state variables, whose behavior over time (timelines) is governed by a set of temporal constraints (synchronization rules). While the temporal domain is usually assumed to be discrete, here we consider the dense case. Dense timeline-based planning has been recently shown to be undecidable in the general case; decidability (NP-completeness) can be recovered by restricting to purely existential synchronization rules (trigger-less rules). In this paper, we investigate the unexplored area of intermediate cases in between these two extremes. We first show that decidability and non-primitive recursive-hardness can be proved by admitting synchronization rules with a trigger, but forcing them to suitably check constraints only in the future with respect to the trigger (future simple rules). More "tractable" results can be obtained by additionally constraining the form of intervals in future simple rules: EXPSPACE-completeness is guaranteed by avoiding singular intervals, PSPACE-completeness by admitting only intervals of the forms [0,a] and [b,$\infty$[.Comment: In Proceedings GandALF 2018, arXiv:1809.0241

Interval Temporal Logic for Visibly Pushdown Systems

In this paper, we introduce and investigate an extension of Halpern and Shoham\u27s interval temporal logic HS for the specification and verification of branching-time context-free requirements of pushdown systems under a state-based semantics over Kripke structures. Both homogeneity and visibility are assumed. The proposed logic, called nested BHS, supports branching-time both in the past and in the future, and is able to express non-regular properties of linear and branching behaviours of procedural contexts in a natural way. It strictly subsumes well-known linear time context-free extensions of LTL such as CaRet [R. Alur et al., 2004] and NWTL [R. Alur et al., 2007]. The main result is the decidability of the visibly pushdown model-checking problem against nested BHS. The proof exploits a non-trivial automata-theoretic construction