An Eulerian Approach to the Analysis of Krause's Consensus Models

Abstract. In this paper we analyze a class of multi-agent consensus dynamical systems inspired by Krause’s original model. As in Krause’s, the basic assumption is the so-called bounded confidence: two agents can influence each other only when their state values are below a given distance threshold R. We study the system under an Eulerian point of view considering (possibly continuous) probability distributions of agents and we present original convergence results. The limit distribution is always necessarily a convex combination of delta functions at least R far apart from each other: in other terms these models are locally aggregating. The Eulerian perspective provides the natural framework for designing a numerical algorithm, by which we obtain several simulations in 1 and 2 dimensions

Program schemes with deep pushdown storage.

Inspired by recent work of Meduna on deep pushdown automata, we consider the computational power of a class of basic program schemes, TeX, based around assignments, while-loops and non- deterministic guessing but with access to a deep pushdown stack which, apart from having the usual push and pop instructions, also has deep-push instructions which allow elements to be pushed to stack locations deep within the stack. We syntactically define sub-classes of TeX by restricting the occurrences of pops, pushes and deep-pushes and capture the complexity classes NP and PSPACE. Furthermore, we show that all problems accepted by program schemes of TeX are in EXPTIME

A unifying look at sequence submodularity

Several real-world problems in engineering and applied science require the selection of sequences that maximize a given reward function. Optimizing over sequences as opposed to sets requires exploring an exponentially larger search space and can become prohibitive in most cases of practical interest. However, if the objective function is submodular (intuitively, it exhibits a diminishing return property), the optimization problem becomes more manageable. Recently, there has been increasing interest in sequence submodularity in connection with applications such as recommender systems and online ad allocation. However, mostly ad hoc models and solutions have emerged within these applicative contexts. In consequence, the field appears fragmented and lacks coherence. In this paper, we offer a unified view of sequence submodularity and provide a generalized greedy algorithm that enjoys strong theoretical guarantees. We show how our approach naturally captures several application domains, and our algorithm encompasses existing methods, improving over them. (C) 2021 The Authors. Published by Elsevier B.V

Through the lens of sequence submodularity

Several real-world problems in engineering and applied science require the selection of sequences that maximize a given reward function. Optimizing over sequences as opposed to sets requires exploring an exponentially larger search space and can become prohibitive in most cases of practical interest. However, if the objective function is submodular (intuitively, it exhibits a diminishing return property), the optimization problem becomes more manageable. Recently, there has been increasing interest in sequence submodularity in connection with applications such as recommender systems and online ad allocation. However, mostly ad hoc models and solutions have emerged within these applicative contexts. In consequence, the field appears fragmented and lacks coherence. In this paper, we offer a unified view of sequence submodularity and provide a generalized greedy algorithm that enjoys strong theoretical guarantees. We show how our approach naturally captures several application domains, and our algorithm encompasses existing methods, improving over them

I sistemi multi-agents e gli algoritmi di consenso

Recently, multi-agent systems have become a central study topic in many different disciplines including biology, engineering, physics, and social science. This has led to the emergence of large and constantly growing interdisciplinary research field, known as network science. The analysis of the mathematical models describing such systems has achieved significant results, but remains mostly an open research field, where many fundamental breakthroughs are expected in the next years. Such analysis is especially motivated by the quest for the development of tools for control and design of such systems. In this paper, we deal with consensus algorithms, an important example of design of multi-agent systems that has been inspired by the dynamics of cooperative systems in natural and social sciences

Dietary habits and nutritional biomarkers in Italian type 1 diabetes families: evidence of unhealthy diet and combined-vitamin-deficient intakes

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Mejora del olmo para resistencia a DED: clones italianos y características de su madera

In Italy, an elm breeding program to develop Dutch elm disease-resistant trees has been established by cross-breeding Asian elms with indigenous species, in order to produce individuals that combine resistance of the first with growth characteristics and higher degree of environmental adaptability of the second. Thus, the favourable adaptation of Ulmus pumila in Italy has been explored: «San Zanobi» and «Plinio» are two recent results of this research and many others promising clones as «FL090», «FL146», «FL441», «FL568», «FL634», are in the final stage of field testing. The resistance levels of all these clones were significantly higher level of resistance than «Lobel» and «Urban» in several assessments during different years. First technological tests indicate that the wood characteristics of «San Zanobi» and «FL090» clones are comparable to those of elm wood traditionally present on the market, thus highlighting that those clones is likely to satisfy the elm wood demand. The present characterisation needs to be confirmed by further evaluations of mature trees having bigger diameters and allowing industrial trials, still not available so far.En Italia, el programa de mejora genética del olmo para la obtención de árboles resistentes a la grafiosis se ha desarrollado a partir del cruzamiento de olmos asiáticos con especies nativas, y tiene por objetivo producir individuos que combinen la resistencia de los primeros con las características vegetativas y el alto grado de adaptación al ambiente de los segundos. Por esta razón, se ha aprovechado la favorable adaptación de Ulmus pumila en Italia: «San Zenobi» y «Plinio » son dos resultados recientes de estas investigaciones, y otros muchos clones prometedores como «FL090», «FL146», «FL441», «FL568» y «FL634» están en las fases finales de las pruebas de campo. Los niveles de resistencia de todos estos clones fueron significativamente mayores, en diferentes ensayos, que los niveles de resistencia de «Lobel» y «Urban ». Los primeros ensayos tecnológicos han mostrado que las características de la madera de los clones «San Zenobi» y «FL090» son comparables a los de las maderas de olmo tradicionalmente presentes en el mercado, indicando que esos clones pueden probablemente satisfacer las demandas de madera. La actual caracterización debe ser confirmada con nuevas evaluaciones en árboles maduros de mayores diámetros y mediante ensayos industriales aún no disponibles