1,720,954 research outputs found
GOLIATH: A Decentralized Framework for Data Collection in Intelligent Transportation Systems
Full text linkIntelligent Transportation Systems (ITSs) technology has advanced during the past years, and it is now used for several applications that require vehicles to exchange real-time data, such as in traffic information management. Traditionally, road traffic information has been collected using on-site sensors. However, crowd-sourcing traffic information from onboard sensors or smartphones has become a viable alternative. State-of-the-art solutions currently follow a centralized model where only the service provider has complete access to the collected traffic data and represent a single point of failure and trust. In this paper, we propose GOLIATH, a blockchain-based decentralized framework that runs on the In-Vehicle Infotainment (IVI) system to collect real-time information exchanged between the network's participants. Our approach mitigates the limitations of existing crowd-sourcing centralized solutions by guaranteeing trusted information collection and exchange, fully exploiting the intrinsic distributed nature of vehicles. We demonstrate its feasibility in the context of vehicle positioning and traffic information management. Each vehicle participating in the decentralized network shares its position and neighbors' ones in the form of a transaction recorded on the ledger, which uses a novel consensus mechanism to validate it. We design the consensus mechanism resilient against a realistic set of adversaries that aim to tamper or disable the communication. We evaluate the proposed framework in a simulated (but realistic) environment, which considers different threats and allows showing its robustness and safety properties
Feasibility study of a blockchain-based framework for decentralized traffic monitoring
Full text linkLAUREA MAGISTRALEQuesta tesi riassume il lavoro di ricerca effettuato sullo studio di
fattibilità relativo ad un nuovo framework decentralizzato basato sulla
blockchain che sia in grado di raccogliere informazioni sul traffico in
tempo reale.
Vengono presentati ed analizzati i metodi più avanzati e i servizi
attualmente utilizzati per il raccoglimento delle informazioni sul traf-
fico e discutiamo i vantaggi e gli svantaggi che essi offrono. La natura
centralizzata dei servizi più comunemente usati per il raccoglimento
delle informazioni sul traffico, come Google Maps, Waze e i servizi
offerti dalle autorità locali, porta alla possibilità da parte del fornitore
del servizio di limitare l’accesso ai dati raccolti in maniera arbitraria.
Il framework proposto punta ad offrire un’alternativa decentraliz-
zata ai servizi centralizzati per il raccoglimento delle informazioni sul
traffico. Per questo motivo, è stato definito un threat model coerente
con il contesto del framework su cui è stata basata la definizione dei
requisiti non funzionali relativi alla sicurezza.
Viene illustrato come è stato progettato il meccanismo di consenso
che regola la blockchain attraverso la definizione di come viene rag-
giunto il consenso distribuito e delle regole che impongono la validità
del contenuto Informativo dei blocchi che compongono la blockchain.
Le prorietà relative alla sicurezza dell’algoritmo di consenso vengono
dimostrate con un approccio matematico.
Un nuovo simulatore basato su OMNeT++, Veins e SUMO viene
descritto ed implementato al fine di testare il framework proposto e
di studiare la sua fattibilità in uno scenario realistico.
Vengono presentati gli esperimenti che sono stati condotti sul frame-
work per studiare come i suoi parametri principali influiscono sulla
sua resa e per determinare se il framework è effettivamente in grado
di resistere agli attacchi descritti nel threat model.
Infine vengono discussi i risultati ottenuti tramite gli esperimenti, e
vengono anche commentate le ragioni per le quali il comportamento
del framework proposto ottenuto negli esperimenti è coerente con le
intenzioni che hanno guidato la fase di progettazione.This thesis summarizes the research that we carried out on the feasi-
bility study of a novel decentralized and blockchain based framework
that can be sued to collect real-time traffic information.
We present and analyze the state-of-the-art methods and currently
used services for traffic information gathering, and we characterize
the advantages and the disadvantages that they offer. The centralized
nature of commonly used traffic information gathering services like
Google Maps, Waze or those offered by local authorities, leads to the
possibility for the service provider of arbitrarily restricting the access
to the traffic information.
The proposed framework aims at offering a decentralized alternative
to centralized traffic information gathering services. For this reason,
we defined a reasonable threat model and based the definition of
non-functional security requirements on it.
We illustrate how we designed the consensus mechanism that regu-
lates the blockchain data structure by defining how distributed consen-
sus is reached and the rules to enforce the validity of the information
content of the blocks that form the blockchain. Through a mathemati-
cal approach we show the security properties of the adopted consensus
algorithm.
We describe and implement a new simulator based on OMNeT++,
Veins and SUMO to test the proposed framework and study its feasi-
bility in a realistic scenario.
We show the experiments that we conducted on the proposed frame-
work in order to study how its main parameters affect the performance
and to determine if it can actually resist the attacks defined in the
threat model.
Finally, we discuss the results of the experiments and comment why
the obtained behaviour is consistent with the intentions that drove the
design phase
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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