1,721,026 research outputs found
A classification procedure for exploitable reserves
No full textProposes a classification procedure for minable reserves for use by mining companies. After reviewing resource/reserves concepts and definitions, the interrelationship between reserves and mining project is examined with a view to establishing a classification based on: a) considerations of economic feasibility, and b) level of confidence of the design itself. The described approach relies on the probabilistic evaluation of Net Present Value (NPV) and is presented as an operational procedure for recognizing and characterizing the random technical and economic magnitudes of mine designs with particular reference to the reserves. -Author
De Nicola, A., Giovinazzi, S., Guarascio, M., Rizzi, P., & Villani, M. L. Gamified decision making for a participatory post-crisis recovery: A model based process.
No full textDecision-making for post-crisis recovery of urban environments may much benefit from participatory processes enlarged to the impacted communities, as these decisions will target their wellbeing and future resilience. Modern technology certainly helps in the creation of focus groups and in facilitating the exchange of ideas among them, but other aspects such as people engagement, quality of the collected ideas, and support to their negotiation, need to be taken into account when planning an effective decision making process. We propose to use gaming simulation as a means to engage citizens in the post-crisis recovery decision process, and a model-based approach to support the representation of decision proposals, their comparison and collaborative definition of final decisions. We present our experience of a gaming simulation, named R-EAGLE-S (L'Aquila Rises Simulation), about recovery decision proposals for L'Aquila city in Italy, after a severe earthquake in 2009
Network topology
No full textNetworks are a convenient and powerful tool for modeling many real world processes, crossing different industrial, sociological and scientific areas, that exhibit some sort of interaction, called edge or link, between different target entities, called nodes
An empirical comparison of collaborative filtering approaches on netflix data
Full text linkRecommender systems are widely used in E-Commerce for making automatic suggestions of new items that could meet the interest of a given user. Collaborative Filtering approaches compute recommendations by assuming that users, who have shown similar behavior in the past, will share a common behavior in the future. According to this assumption, the most effective collaborative filtering techniques try to discover groups of similar users in order to infer the preferences of the group members. The purpose of this work is to show an empirical comparison of the main collaborative filtering approaches, namely Baseline, Nearest Neighbors, Latent Factor and Probabilistic models, focusing on their strengths and weaknesses. Data used for the analysis are a sample of the well-known Netix Prize database. Copyright owned by the authors
Network models
No full textNetwork models are aimed at expressing mathematical models for explaining and justifying basic network properties. The properties of interest span from basic structural properties to more complex characteristic such as community structures and models for link formation and node characterization. These models can be exploited for understanding the formation evolution of the network and predicting its behavior in the future. This article is devoted at describing some reference network models and at studying their properties and applications
Utilizzo combinato di codici numerici per simulazioni di cavità coltivate per idrodissoluzione nel salgemma
No full textCombined application of numerical codes for the mechanical simulation of salt caverns. The numerical methods are probably the best solution tools geomechanics has today far the solution of stress analysis problems. ln the paper is discussed about two codes, used recently by the authors, in the field of application of stress analysis of solution mined salt cavities. Then there is a brief presentation of EXAMINE, a 3D BEM numerical code, able to perform spatial analysis of elastic behavior of structures. lts pe1jormances are witnessed by the results of the studies developed in the DJCAMP of the University of Trieste (ltaly). The study has been conducted on the basis of experimental tests data and other information were deducted from solution mining world-wide literature. A finite difference numerical code (FLAC) has been adopted especially for the simulation of viscoplastic field of deformation. In the second part of the paper there is a presentation of the results and of the methodologies followed in simulating different pressurisation in the caverns, involving elastic analysis. The main objectives of this section were the classification of the numerical solution in order to qualify model deviations from reality and the ability to quantify the caverns stress reaction developed against the different boundary conditions
Sicurezza ferroviaria: evoluzioni degli scopi e dei metodi di valutazione del rischio
No full textLa pratica della sicurezza ferroviaria si basa su una successione di metodologie
ed obiettivi stratificati nel tempo. I regolamenti, le disposizioni, le istruzioni, le procedure,
ecc. hanno guidato, sotto la vigilanza dell’autorità ministeriale, la gestione
della sicurezza dalla nascita del servizio fino alla fine degli anni ’90, demandandola
ad una base di prescrizioni implicitamente orientate alla prevenzione dei malfunzionamenti,
delegando quindi alle “Ferrovie dello Stato” la gestione delle indagini interne
in occasione di incidenti ed infine rilevando verso esterno per il solo effetto di
vigilanza sotto il profilo penale esercitato dalla magistratura ordinaria.
Alla medesima forma unitaria, attribuita al soggetto erogatore del servizio tecnico,
in regime di trasformazione tecnologica progressiva, è risultata allineata
l’interpretazione dell’incidente quale errore di sistema caratterizzato da responsabilità
certa e perseguibile, con conseguente sensibilità della struttura e delle procedure
alla prevenzione delle modalità di malfunzionamento identificando le possibili soluzioni
tecnologiche (gestione reattiva della sicurezza).The practice of railway safety is based on a series of layered methods and
objectives over time. The regulations, rules, instructions, procedures led, under the
supervision of the ministerial authority, the safety management of the service from
birth until the late 90s, leaving it to requirements implicitly oriented to the
prevention of malfunctions, then delegating to the " Ferrovie dello Stato " the
management of internal investigations at accident.
At the same unitary form, attributed to the provider for technical service, under a
progressive technological change, was aligned with the interpretation of the incident
as a system error that is characterized by certain responsibilities and liable, resulting
in sensitivity of the structure and of the procedures to prevent failure mode through
the identification of possible technological solutions (reactive security management)
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