1,092 research outputs found
MacroSwarm: A scala framework for swarm programming
No full textProgramming swarm behaviors is a challenging task, due to the need to express collective behaviors in terms of local interactions among simple agents. Even if several programming frameworks have been proposed, they are often based on low-level abstractions, which makes the development of swarm applications complex and error-prone. Thus, we present MacroSwarm, an aggregate programming framework for the development of swarm behaviors. With this framework, it is possible to define a large variety of swarm behaviors, starting from simple movements to more complex ones, such as aggregation, flocking, and collective decision-making. In this paper, we present the main features of the framework and some simple examples of its API usage
Stratigraphic architecture of Late Quaternary deposits in the Lower Arno Plain (Tuscany, Italy)
No full textDetailed sedimentological investigation of two continuously-cored boreholes, up to 106 m deep,
combined with stratigraphic analysis of about 300 well logs performed for water research in the area between
Cascina and the Tyrrhenian coast, reveal subsurface stratigraphy of Late Quaternary deposits in the lower Arno
Plain.
Facies analysis of the cores allows identification of twelve different facies associations, grouped into alluvial
and coastal depositional systems. A stratigraphic cross section, roughly parallel to present Arno River and 30 km
long, shows the presence of two trangressive-regressive sequences, attributed to the last two interglacial-glacial
cycles (base of OIS 1 and 5e, respectively). Despite significant facies variability from proximal to distal locations,
the basal transgressive surfaces appear as the most readily identifiable features from both core and borehole data,
and constitute a stratigraphic marker that can be physically traced across the entire study area.
The high resolution stratigraphic data shown in this paper are in marked contrast with previous work, and provide
a new stratigraphic framework for the upper portion of the Viareggio Basin
Shape analysis of different populations of clams in relation to their geographical structure
No full text10 pages, 6 figures, 5 tables.Bivalves are excellent candidates for geographically based studies of the morphological variation in individuals of different populations based on the analysis of their shape profiles. In this study, we quantified the overall shell shape differences in individuals of different populations of Ruditapes decussatus and Ruditapes philippinarum in relation to their geographical and genetic distances. A total of 395 and 124 individuals of R. decussatus (nine populations) and R. philippinarum (four populations), respectively, were sampled in different Mediterranean and Atlantic coastal locations. Pictures of the left valve were taken from all individuals. Their profiles were analysed using elliptic Fourier analysis. Mean outlines were computed. In order to classify different individuals for species, the coefficients of harmonic equations were analysed by partial least square discriminant analysis and soft independent modelling of class analogy. The results showed a high percentage of correct classification (99%) between the two species in the independent test. We found that the morphological distance between R. philippinarum and R. decussatus is higher than the morphological distance among populations of the same species. The absence of correspondence between the geographical location and the pattern of morphological and genetic variation indicates the occurrence of a reaction norm in the morphological adaptation of shell shapes to different local environmental conditions.We would like to thank Davide Cascione for his help during the process of image acquisition. Jacopo Aguzzi is a Fellow of the ‘Juan de la Cierva’ Postdoctoral Program (MECSpain).Peer reviewe
Characterization of aquifer systems from high-resolution subsurface stratigraphy: the case of the eastern Valdarno basin (Tuscany, Italy)
No full textRealistic models of ground water circulation and transport in modern alluvial
and coastal plains demand an accurate reconstruction of subsurface
sedimentary architecture. In this study, we propose the characterization of a
multilayered aquifer from the subsiding eastern Valdarno Basin, a strategic
area far both water research and pollution issues, between the city of
Pontedera and S. Croce.
An integrated sedimentological, stratigraphic and micropaleontological study of
six continuously cored boreholes allows the detailed reconstruction of Pliocene
to Quaternary stratigraphy in the uppermost 100 m, and shows how a
multidisciplinary approach may represent a successful tool to define
three-dimensional facies relationships with in sedimentary bodies, and thus
aquifer geometries. Moreover, AMS 14C dates associated to Sr isotope data
prompt to place the identified stratigraphic units in a worthy
chronostratigraphic framework, with a coherent depositional evolution in terms
of space and time.
The study area, oriented SW-NE along the Arno River course, is rimmed to the
south and to the north by the Pisa and the Cerbaie Hills, respectively, both
formed by Plio-Quaternary marine and continental deposits. A fault, located
a long the southern margin of the Cerbaie Hills, causes the NNW-dipping, below
the Arno-plain, of the Plio-Quaternary deposits cropping out o n the Pisa Hills.
Stratigraphic architecture in the study area is varied. Except far the Holocene
succession, consisting mainly of fine-grained alluvial-plain deposits lying onto
transgressive swamp deposits and showing a homogenous spatial distribution,
the pre-Holocene deposits exhibit noticeable distinct features west and east of
Pontedera, respectively, due to the activity of a normal fault with an Apenninic
orientation, causing the lowering of the west side of the study area. A thick
Pleistocene alluvial succession, made up by a cyclic alternation of
coarse-grained fluvial channel and fine-grained floodplain deposits, is recorded
beneath Pontedera, whereas eastwards the stratigraphic sequence is
characterized by Early-Middle Pliocene deposits, related to coastal-shallow
marine sands with very subordinate alluvial facies.
Given this structural setting, the reconstruction of stratigraphic architecture
leads to the identification, in the uppermost 100 m, of a multilayered confined
aquifer consisting of five aquifer systems (A-E) ranging in age between the
Holocene and the Early-Middle Pliocene.
Aquifer system A developed during the Holocene and exhibits a markedly
lenticular geometry recording the recent dynamics of the Arno River. The
underlying aquifer system (B), Lower-Middle Pleistocene-Holocene in age,
consists of sands an d gravels of fluvial origin and is recorded only in the
western sector of the examined area. The lower three aquifer systems (C-D-E),
characterizing the eastern sector of the study area, mainly consist of sandy
shallow-marine deposits, Early to Middle Pliocene in age, showing a cyclic
arrangement.
The Quaternary aquifer systems (A-B) exhibit a strongly lenticular shape,
reflecting their fluvial origin, while the Early-Middle Pliocene aquifer systems
(C-D-E) display a higher lateral continuity, as expected from sedimentary
bodies deposited in coastal-littoral setting.
The geological framework and the structural setting suggest the identification
of water recharge areas in the Middle Pliocene sandy deposits cropping out on
the Pisa Hills, taking into account their NNW dipping toward the Arno Plain
Low-code design of collective systems with ScaFi-Blocks
No full textScaFi-Blocks is a visual, low-code programming environment for designing and implementing swarm algorithms. Built on the ScaFi aggregate computing framework and the Blockly visual programming library, ScaFi-Blocks enables users to visually compose algorithms using intuitive building blocks, abstracting away the complexities of traditional swarm programming frameworks. This approach simplifies the development of collective behaviours for a wide range of swarm systems, including robot swarms, IoT device ensembles, and sensor networks, fostering broader accessibility and innovation within the field. This contribution bridges the gap between visual programming and textual code, lowering the barrier to entry for non-experts while promoting a deeper understanding of aggregate computing principles
MacroSwarm: A Field-Based Compositional Framework for Swarm Programming
No full textSwarm behaviour engineering is an area of research that seeks to investigate methods for coordinating computation and action within groups of simple agents to achieve complex global goals like collective movement, clustering, and distributed sensing. Despite recent progress in the study and engineering of swarms (of drones, robots, vehicles), there is still need for general design and implementation methods that can be used to define complex swarm coordination in a principled way. To face this need, this paper proposes a new field-based coordination approach, called MacroSwarm, to design fully composable and reusable blocks of swarm behaviour. Based on the macroprogramming approach of aggregate computing, it roots on the idea of modelling each block of swarm behaviour by a purely functional transformation of sensing fields into actuation description fields, typically including movement vectors. We showcase the potential of MacroSwarm as a framework for collective intelligence by simulation, in a variety of scenarios including flocking, morphogenesis, and collective decision-making
Il confronto internazionale tra prezzi dei farmaci: aspetti metodologici, principali risultati in letteratura e studio sui farmaci con obbligo di prescrizione
No full textIl capitolo opera un confronto internazionale tra i prezzi dei farmaci in Italia rispetto a Francia, Germania, Spagna, Regno Unito, Stati Uniti, Olanda e Grecia. E' stata condotta una riflessione il più possibile rappresentativa del mercato, tenendo conto dell'esigenza di realizzare un confronto tra prodotti omogenei
Towards Reinforcement Learning-based Aggregate Computing
No full textRecent trends in pervasive computing promote the vision of Collective Adaptive Systems (CASs): large-scale collections of relatively simple agents that act and coordinate with no central orchestrator to support distributed applications. Engineering global behaviour out of local activity and interaction, however, is a difficult task, typically addressed by try-and-error approaches in simulation environments. In the context of Aggregate Computing (AC), a prominent functional programming approach for CASs based on field-based coordination, this difficulty is reflected in the design of versatile algorithms preserving efficiency in a variety of environments. To deal with this complexity, in this work we propose to apply Machine Learning techniques to automatically devise local actions to improve over manually-defined AC algorithms specifications. Most specifically, we adopt a Reinforcement Learning-based approach to let a collective learn local policies to improve over the standard gradient algorithm—a cornerstone brick of several higher-level self-organisation algorithms. Our evaluation shows that the learned policies can speed up the self-stabilisation of the gradient to external perturbations
MacroSwarm: A Field-based Compositional Framework for Swarm Programming
No full textSwarm behaviour engineering is an area of research that seeks to investigate methods and techniques for coordinating computation and action within groups of simple agents to achieve complex global goals like pattern formation, collective movement, clustering, and distributed sensing. Despite recent progress in the analysis and engineering of swarms (of drones, robots, vehicles), there is still a need for general design and implementation methods and tools that can be used to define complex swarm behaviour in a principled way. To contribute to this quest, this article proposes a new field-based coordination approach, called MacroSwarm, to design and program swarm behaviour in terms of reusable and fully composable functional blocks embedding collective computation and coordination. Based on the macroprogramming paradigm of aggregate computing, MacroSwarm builds on the idea of expressing each swarm behaviour block as a pure function, mapping sensing fields into actuation goal fields, e.g., including movement vectors. In order to demonstrate the expressiveness, compositionality, and practicality of MacroSwarm as a framework for swarm programming, we perform a variety of simulations covering common patterns of flocking, pattern formation, and collective decision-making. The implications of the inherent self-stabilisation properties of field-based computations in MacroSwarm are discussed, which formally guarantee some resilience properties and guided the design of the library
Stratigraphic architecture and aquifer systems in the eastern Valdarno Basin, Tuscany
No full textDeveloping a realistic model of high-resolution stratigraphy from the subsurface of modern alluvial and coastal plains is an important first step toward a successful three-dimensional representation of aquifers and aquifer systems. An integrated (stratigraphic, sedimentological and micropalaeontological) study of six cores, 100-115 m long, from the eastern Valdarno Basin, Tuscany, enables the detailed reconstruction of Pliocene to Quaternary subsurface architecture between Pontedera and S. Croce sull'Arno. Pollen data from lagoonal sediments and strontium isotope dating of shallow-marine deposits provide the basis for the construction of a reliable chronologic framework for the study succession. Stratigraphic correlations, based upon detailed facies anal ysis, show a varied facies architecture in the study area. Beneath the Holocene succession, which is about 40 m thick and consists of alluvial deposits resting onto transgressive swamp clays, pre-Holocene deposits display remarkably different characteristics from Pontedera toward the basin margin, likely as a result of tectonic activity due to a normal fault running parallel to the Apenninic chain. In the Pontedera area, a thick succession of Pleistocene alluvial deposits, showing a cyclic alternation of fluvial-channel (gravel/sand) and floodplain (clay) facies associations is the dominant stratigraphic feature. By contrast, lower-middle Pliocene deposits, characterized by alternating coastal and shallow-marine deposits, with very subordinate alluvial facies, are recorded at shallow depths, west of S. Croce. A significantly improved stratigraphic architecture in the uppermost 100 m enables detailed reconstruction of aquifers geometry in the eastern Valdarno Basin. With respect to previous work, documenting the presence of one aquifer only, a multilayered confined aquifer, made up of five aquifer systems ranging in age from Middle Pliocene to Holocene, is identified in this study. Lenticular and sheet-like geometries of these aquifer systems are reconstructed, as a function of the alluvial versus littoral origin of their constituent deposits. According to the geological framework, the Pliocene to Quaternary sands cropping out on the Pisa Hills are likely to represent the meteoric-water recharge area for the aquifers of the eastern Valdarno Basin
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