Correlation Clustering with Adaptive Similarity Queries

In correlation clustering, we are given $n$ objects together with a binary similarity score between each pair of them. The goal is to partition the objects into clusters so to minimise the disagreements with the scores. In this work we investigate correlation clustering as an active learning problem: each similarity score can be learned by making a query, and the goal is to minimise both the disagreements and the total number of queries. On the one hand, we describe simple active learning algorithms, which provably achieve an almost optimal trade-off while giving cluster recovery guarantees, and we test them on different datasets. On the other hand, we prove information-theoretical bounds on the number of queries necessary to guarantee a prescribed disagreement bound. These results give a rich characterization of the trade-off between queries and clustering error

Chapter Nabladot Analysis of Hybrid Theories in International Relations

Scientific research in International Relations has produced a growing corpus of empirically grounded formal theoretical models of phenomena ranging from deterrence to systemic polarity, from conditions of peace to the onset of war. Many of these important theories contain a mix of continuous and discrete dimensions, causal variables, and parameters. Analysis and understanding of this fundamental and intriguing class of theories containing functions with a mix of continuous and discrete variables has puzzled generations of social scientists and applied mathematicians. This challenging and longstanding puzzle now has a solution. Here we demonstrate how the recently created calculus with nabladot operators is beginning to uncover previously unknown properties of hybrid international phenomena. Results include new concepts and precise principles on causal relationships, previously unknown political features, and fundamental properties of probabilistic causality, demonstrated through nabladot analysis of international events, crisis dynamics, and warfare

Correlation Clustering with Adaptive Similarity Queries

In correlation clustering, we are given n objects together with a binary similarity score between each pair of them. The goal is to partition the objects into clusters so to minimise the disagreements with the scores. In this work we investigate correlation clustering as an active learning problem: each similarity score can be learned by making a query, and the goal is to minimise both the disagreements and the total number of queries. On the one hand, we describe simple active learning algorithms, which provably achieve an almost optimal trade-off while giving cluster recovery guarantees, and we test them on different datasets. On the other hand, we prove information-theoretical bounds on the number of queries necessary to guarantee a prescribed disagreement bound. These results give a rich characterization of the trade-off between queries and clustering erro

Chapter Introduzione. Umberto Gori e le Relazioni Internazionali in Italia

Umberto Gori has held the first chair of International Relations in Italy and has been the first scholar to address a series of central topics in the analysis of foreign policy and international politics. Those who browse, even if only rapidly, his rich bibliography cannot but be struck by the great variety of the topics examined: from the first works of a predominantly legal nature, we move on to studies centered on methodological and epistemological issues, relations between states, analysis of foreign policy in general and Italian foreign policy in particular, Peace Research, strategic affairs, intelligence, and finally the impact of the information and digital revolution on international politics and contemporary strategy. What holds together so many different issues is, firstly, a constant attention to methodology and, secondly, a clear preference for a predominantly operational approach, in the belief that knowledge must always be functional to decision and action. These basic attitudes are reflected not only in his strongly characterized research agenda, but also in the twofold nature of his teaching commitment: on the one hand, Gori taught outside the university classrooms, at military and governmental institutions, for decades; on the other hand, he introduced issues traditionally reserved to diplomacy and security institutions into the Italian academic context. Such a propensity to build bridges between different worlds - academic, military, technological, diplomatic, financial - and a research vocation that has never failed make Umberto Gori a figure indissolubly linked to the birth and development of International Relations in Italy

Chapter L’equilibrio di potenza nella storiografia fiorentina

Although Francesco Guicciardini is usually credited with the idea of balance of power, other Florentine historians prior to him had had similar insights. The essay presents the evolution of the notion of balance of power in Florentine historiography from the 14th-century chronicles of Giovanni and Matteo Villani to Guicciardini himself. Florentine historians put forward two basic meanings of balance of power, first as aggregation of forces against the most powerful state, second as an arrangement of the international system as a whole. The former is based on the elementary idea that those who fear the strongest state create alliances with those who share similar concerns, and it amounts to an ad hoc security tool; the latter entails the awareness of the existence of a system of states, which gradually came up from the beginning of the 15th century onwards

Chapter Umberto Gori: un profilo biobibliografico

Academic biographical profile and scientific publications of Umberto Gori