Search results for "Arity"
showing 10 items of 2893 documents
A Chain of Words as an Introduction: Human Dignity, Language, Identity, Citizenship, Values, Human Capital and Urban Spaces
2022
To analyze the issue of cities-migrants interactions, as well as social-monetary values interactions, it is necessary to place it in a “higher” context, in order not to risk losing the necessary connection with universal ethical principles, and in a “broader” one, in which understanding complexity on a global scale interprets local conditions. The study of migration flows and urban dynamics, as well as housing markets, through theoretical paradigms and scientific tools from different disciplines provides an opportunity to learn and compare, dialogue and interface with new keys to understanding the problem, or with alternative interpretations and unprecedented perspectives in the path of mul…
The Whole Is Greater than the Sum of the Parts: A Multilayer Approach on Criminal Networks
2022
Traditional social network analysis can be generalized to model some networked systems by multilayer structures where the individual nodes develop relationships in multiple layers. A multilayer network is called multiplex if each layer shares at least one node with some other layer. In this paper, we built a unique criminal multiplex network from the pre-trial detention order by the Preliminary Investigation Judge of the Court of Messina (Sicily) issued at the end of the Montagna anti-mafia operation in 2007. Montagna focused on two families who infiltrated several economic activities through a cartel of entrepreneurs close to the Sicilian Mafia. Our network possesses three layers which sha…
Analysis of Users Behaviour from a Movie Preferences Perspective
2018
Despite their tremendous popularity, Online Social Networks (OSNs) have several issues related to the privacy of social users. These issues have motivated researchers to develop OSN services that take advantage of the decentralized platforms (such as P2P systems or opportunistic networks). Decentralized Online Social Networks (DOSNs) need specific approaches to manage the decentralization of social data. In particular, data availability is one of the main issues and current proposals exploit properties of the social relationships to manage it. At the best of our knowledge, there are no proposals which exploit similarity between users, expressed with the term homophily. Homophily has been we…
Dissimilarity Measures for the Identification of Earthquake Focal Mechanisms
2013
This work presents a study about dissimilarity measures for seismic signals, and their relation to clustering in the particular problem of the identification of earthquake focal mechanisms, i.e. the physical phenomena which have generated an earthquake. Starting from the assumption that waveform similarity implies similarity in the focal parameters, important details about them can be determined by studying waveforms related to the wave field produced by earthquakes and recorded by a seismic network. Focal mechanisms identification is currently investigated by clustering of seismic events, using mainly cross-correlation dissimilarity in conjunction with hierarchical clustering algorithm. By…
Graph Comparison and Artificial Models for Simulating Real Criminal Networks
2021
Network Science is an active research field, with numerous applications in areas like computer science, economics, or sociology. Criminal networks, in particular, possess specific topologies which allow them to exhibit strong resilience to disruption. Starting from a dataset related to meetings between members of a Mafia organization which operated in Sicily during 2000s, we here aim to create artificial models with similar properties. To this end, we use specific tools of Social Network Analysis, including network models (Barabási-Albert identified to be the most promising) and metrics which allow us to quantify the similarity between two networks. To the best of our knowledge, the DeltaCo…
A new feature selection strategy for K-mers sequence representation
2014
DNA sequence decomposition into k-mers (substrings of length k) and their frequency counting, defines a mapping of a sequence into a numerical space by a numerical feature vector of fixed length. This simple process allows to compute sequence comparison in an alignment free way, using common similarities and distance functions on the numerical codomain of the mapping. The most common used decomposition uses all the substrings of length k making the codomain of exponential dimension. This obviously can affect the time complexity of the similarity computation, and in general of the machine learning algorithm used for the purpose of sequence classification. Moreover, the presence of possible n…
Alignment free Dissimilarities for sequence classification
2015
One way to represent a DNA sequence is to break it down into substrings of length L, called L-tuples, and count the occurence of each L-tuple in the sequence. This representation defines a mapping of a sequence into a numerical space by a numerical feature vector of fixed length, that allows to measure sequence similarity in an alignment free way simply using disssimilarity functions between vectors. This work presents a benchmark study of 4 alignment free disssimilarity functions between sequences, computed on their L-tuples representation, for the purpose of sequence classification. In our experiments, we have tested the classes of geometric-based, correlation-based and information-based …
The recent change in the Italian policies for photovoltaics: Effects on the payback period and levelized cost of electricity of grid-connected photov…
2015
Abstract This paper provides an economic analysis of the investment in grid-connected PV (photovoltaic) systems installed on the rooftops of buildings located in densely urbanised contexts. The analysis was applied to some case studies that were selected as representative of the latitudes of the southern, central and northern Italy. The returns of the investment in PV systems were investigated with the aim of comparing the impact of the current PV policy, based on the tax credit scheme, with the FIT (feed-in tariff) scheme, in force until July 2013. The cash flows related to the disbursements and benefits during the lifetime of the investment were computed for each combination of orientatio…
Influence of Operational Strategies for the Recovery of Magnesium Hydroxide from Brines at a Pilot Scale
2022
The continuous depletion of minerals caused by land mining and the increase in their demand have pushed the development of novel sustainable technological processes for mineral recovery from unconventional sources. In this context, magnesium (Mg) has gained considerable attention for its peculiar properties and high relevance of its compounds, such as magnesium hydroxide, Mg(OH)2. In the present work, the influence of several operating conditions on the Mg(OH)2 precipitation process was thoroughly investigated by adopting a novel multiple feed-plug flow reactor. The influence of (i) initial Mg2+ concentrations in the feed stream; (ii) brine and alkaline flow rates; and (iii) the product rec…
A Multi-Port Approach to Solve Distribution Networks with Meshes and PV Nodes
2007
A new methodology based on the backward/forward (b/f) technique for the load flow solution in distribution systems is here proposed. The methodology takes efficiently into account the fixed voltage nodes and uses a reduced bus impedance matrix. In this way, it is possible to attain, for the unknowns at the PV nodes, the same values that are attainable solving the network with the methods adopted for transmission systems. With the same methodology it is possible to take into account also the meshes. If the network contains only meshes, the relevant model is linear and it is the one including the compensation currents. The presence of PV nodes introduces non linearity in the model and an iter…