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Revisiting street intersections using slot-based systems
No full textSince their appearance at the end of the 19th century, traffic lights have been the primary mode of granting access to road intersections. Today, this centuries-old technology is challenged by advances in intelligent transportation, which are opening the way to new solutions built upon slot-based systems similar to those commonly used in aerial traffic: what we call Slot-based Intersections (SIs). Despite simulation-based evidence of the potential benefits of SIs, a comprehensive, analytical framework to compare their relative performance with traffic lights is still lacking. Here, we develop such a framework. We approach the problem in a novel way, by generalizing classical queuing theory. Having defined safety conditions, we characterize capacity and delay of SIs. In the 2-road crossing configuration, we provide a capacity-optimal SI management system. For arbitrary intersection configurations, near-optimal solutions are developed. Results theoretically show that transitioning from a traffic light system to SI has the potential of doubling capacity and significantly reducing delays. This suggests a reduction of non-linear dynamics induced by intersection bottlenecks, with positive impact on the road network. Such findings can provide transportation engineers and planners with crucial insights as they prepare to manage the transition towards a more intelligent transportation infrastructure in cities
A Lifecycle for Data Sharing Agreements: How it works out
No full textAn electronic Data Sharing Agreement (DSA) is a human-readable, yet machine-processable contract, regulating how organizations and/or individuals share data. In past work, we have shed light on DSA engineering, i.e., the process of studying how data sharing is ruled in traditional legal human-readable contracts and mapping their fields (and rules) into formats that are machine-processable, leading to the transposition of a traditional legal contract into the electronic DSA. However, the definition of an electronic DSA is only the starting point of a complex DSA lifecycle, driving the contract from its creation to 1) an analysis phase, where the DSA rules are checked against conflicts; and 2) a mapping phase, where the analysed rules are transposed into privacy policies expressed in enforceable languages. This paper presents our vision for the architectural definition of a DSA system, where a lifecycle manager orchestrates: an authoring tool for legal experts, policy experts, and end users; an analyser for checking consistency of the DSA rules; a mapper for encoding rules in a low level language amenable for enforcement
The Italian origins of FAO and Paul Otlet
No full textNowadays the strategic role of international organizations, which manage and provide information systems and library services in the agricultural domain, is universally recognized. This paper focuses on the origin of the Food and Agriculture Organization of the United Nations (FAO) by presenting a critical edition of the Rapport by Paul Otlet to the marquis Cappelli, pr?sident de l?Institut International d?Agricolture (Otlet, 1911) that includes original documents and outlines the first steps taken by the International Institute of Agriculture (IIA), founded in Rome in 1905. The critical edition starts from the original report, preserved in the archival funds of David Lubin, owned by FAO archive and is a collation of IIA?s memorandums preserved in the National Library of Rome, and the copious correspondence, between Otlet and Oscar Bolle, the delegate of Belgium, courteously made available by the Mundaneum
Mobile edge clouds for Information-Centric IoT services
No full textThe number and capabilities of IoT devices will exponentially grow over the next years. Together with the pervasive diffusion of smart personal mobile devices this opens up unprecedented opportunities for contextualised services provided to mobile users, based on their current interests and behaviours. In addition, most of these services will be content-centric rather than host-centric. Cloud computing and Information-Centric Networking (ICN) are therefore two key technologies in this perspective. In both cases, solutions are typically designed for global Internet platforms, while mobile nodes are seen as edge devices from which data are fetched and sent back through pervasive wireless networks (typically, LTE). However, it is questionable whether such an approach will work as expected, e.g., due to data privacy concerns and expected bandwidth shortage of even last-generation cellular networks. In this paper we present a general framework where global cloud and ICN platforms are complemented in a totally synergic way by local clouds formed at the edge of the network by mobile devices, where service provisioning and data management functionalities are offloaded whenever possible (and appropriate). This results in a multi-layer, content- and service-centric approach to IoT data management and service provisioning. We then present performance evaluation results from applying this framework to a specific case where data-centric services are jointly provided by edge devices and by a global cloud platform. Results show that this approach is very promising, as it is able to drastically cut the related cellular-network traffic, and, at the same time, improve the effectiveness of service provisioning to users.The number and capabilities of IoT devices will exponentially grow over the next years. Together with the pervasive diffusion of smart personal mobile devices this opens up unprecedented opportunities for contextualised services provided to mobile users, based on their current interests and behaviours. In addition, most of these services will be content-centric rather than host-centric. Cloud computing and Information-Centric Networking (ICN) are therefore two key technologies in this perspective. In both cases, solutions are typically designed for global Internet platforms, while mobile nodes are seen as edge devices from which data are fetched and sent back through pervasive wireless networks (typically, LTE). However, it is questionable whether such an approach will work as expected, e.g., due to data privacy concerns and expected bandwidth shortage of even last-generation cellular networks. In this paper we present a general framework where global cloud and ICN platforms are complemented in a totally synergic way by local clouds formed at the edge of the network by mobile devices, where service provisioning and data management functionalities are offloaded whenever possible (and appropriate). This results in a multi-layer, content- and service-centric approach to IoT data management and service provisioning. We then present performance evaluation results from applying this framework to a specific case where data-centric services are jointly provided by edge devices and by a global cloud platform. Results show that this approach is very promising, as it is able to drastically cut the related cellular-network traffic, and, at the same time, improve the effectiveness of service provisioning to users
DNA-Inspired Online Behavioral Modeling and Its Application to Spambot Detection
No full textA novel approach to modeling online user behavior extracts and analyzes digital DNA-inspired sequences from users? online actions. Standard DNA analysis techniques can then discriminate between genuine and spambot accounts
Accurate and Efficient Modeling of 802.15.4 Unslotted CSMA/CA through Event Chains Computation
No full textMany analytical models have been proposed for evaluating the performance of event-driven 802.15.4 Wireless Sensor Networks (WSNs), in Non-Beacon Enabled (NBE) mode. However, existing models do not provide accurate analysis of large-scale WSNs, due to tractability issues and/or simplifying assumptions. In this paper, we propose a new approach called Event Chains Computation (ECC) to model the unslotted CSMA/CA algorithm used for channel access in NBE mode. ECC relies on the idea that outcomes of the CSMA/CA algorithm can be represented as chains of events that subsequently occur in the network. Although ECC can generate all the possible outcomes, it only considers chains with a probability to occur greater than a pre-defined threshold to reduce complexity. Furthermore, ECC parallelizes the computation by managing different chains through different threads. Our results show that, by an appropriate threshold selection, the time to derive performance metrics can be drastically reduced, with negligible impact on accuracy. We also show that the computation time decreases almost linearly with the number of employed threads. We validate our model through simulations and testbed experiments, and use it to investigate the impact of different parameters on the WSN performance, in terms of delivery ratio, latency, and energy consumption.
Design and evaluation of a cognitive approach for disseminating semantic knowledge and content in opportunistic networks
No full textIn cyber-physical convergence scenarios information flows seamlessly between the physical and the cyber worlds. Here, users\u27 mobile devices represent a natural bridge through which users process acquired information and perform actions. The sheer amount of data available in this context calls for novel, autonomous and lightweight data-filtering solutions, where only relevant information is finally presented to users. Moreover, in many real-world scenarios data is not categorised in predefined topics, but it is generally accompanied by semantic descriptions possibly describing users\u27 interests. In these complex conditions, user devices should autonomously become aware not only of the existence of data in the network, but also of their semantic descriptions and correlations between them. To tackle these issues, we present a set of algorithms for knowledge and data dissemination in opportunistic networks, based on simple and very effective models (called cognitive heuristics) coming from cognitive sciences. We show how to exploit them to disseminate both semantic data and the corresponding data items. We provide a thorough performance analysis, under various different conditions comparing our results against non-cognitive solutions. Simulation results demonstrate the superior performance of our solution towards a more effective semantic knowledge acquisition and representation, and a more tailored content acquisition
Usage Control on Cloud Systems
No full textCloud Computing is becoming increasingly popular because of its peculiarities, such as the availability on demand of (a large amount of) resources, even for a long time.For this reason, Cloud Computing represents a good solution for those companies that want to outsource part of their software processes. However, Cloud Computing introduces new security and management challenges with respect to traditional systems exposed on the Internet. This paper presents an advanced authorization service based on the Usage Control model to regulate the usage of Cloud resources, focussing on IaaS services. Our framework addresses the issue of long lasting usage of resources, because it allows to define Usage Control policies which are continuously enforced while the access is in progress.In particular, our framework is able to interrupt the usage of such resources when the corresponding policy is not satisfied any more.In this paper, we present the architecture of the proposed framework describing the integration of a Usage Control based authorization service within one of the most popular software for running Cloud services: OpenNebula. Moreover, we describe the implementation of a prototype of the whole framework, along with some performance figures
Bilateral Symmetry of Visual Function Loss in Cone-Rod Dystrophies
No full textPurpose: To investigate bilateral symmetry of visual impairment in cone?rod dystrophy (CRD) patients and understand the feasibility of clinical trial designs treating one eye and using the untreated eye as an internal control.Methods: This was a retrospective study of visual function loss measures in 436 CRD patients followed at the Ophthalmology Department of the Catholic University in Rome. Clinical measures considered were best-corrected visual acuity, focal macular cone electroretinogram (fERG), and Ganzfeld cone-mediated and rod-mediated electroretinograms. Interocular agreement in each of these clinical indexes was assessed by t- and Wilcoxon tests for paired samples, structural (Deming) regression analysis, and intraclass correlation. Baseline and follow-up measures were analyzed. A separate analysis was performed on the subset of 61 CRD patients carrying likely disease-causing mutations in the ABCA4 gene.Results: Statistical tests show a very high degree of bilateral symmetry in the extent and progression of visual impairment in the fellow eyes of CRD patients.Conclusions: These data contribute to a better understanding of CRDs and support the feasibility of clinical trial designs involving unilateral eye treatment with the use of fellow eye as internal control
Procedura per il corretto utilizzo dei misuratori d\u27assetto in dotazione agli Impianti "Bacini Rettilinei"
No full textThe aim of the present Technical Report is to describe the correct use of the trim dynamometers of the towing tank laboratory equipment. These measure instruments, that CNR-INSEAN has got in the 2000s to measure drafts, step up from all the previous ones: the use of two encoders and of simple geometric considerations makes measures independent from the longitudinal position of the tested model, a crucial issue in the past and source of large errors in draft measurements.Obiettivo del presente Rapporto Tecnico ? di descrivere il corretto utilizzo dei dinamometri d\u27assetto in dotazione al laboratorio "Bacini Rettilinei". Questi strumenti di misura di cui il CNR-INSEAN si ? dotato nel primo decennio degli anni duemila per la misura delle sovraimmersioni, permettono un importante passo avanti rispetto a quelli utilizzati in precedenza: l\u27utilizzo di due encoder e di semplici considerazioni geometriche rende le misure indipendenti dalla posizione longitudinale del modello in prova; tale dipendenza che nel passato costituiva una delle pi? grandi fonti d\u27errore nella misura delle sovraimmersioni