1,720,962 research outputs found
Privacy-Preserved Authentication & Communication in Vehicular Ad-Hoc Networks
No full textAs a key component of Intelligent Transportation Systems (ITS), Vehicular Ad hoc Networks (VANETs) enable real-time data exchange, traffic optimization, and smarter mobility. However, large-scale deployment raises critical security and privacy concerns, including message integrity, user anonymity, and protection against unauthorized access. This thesis proposes lightweight cryptographic protocols for secure and privacy-preserving authentication in both centralized and decentralized VANETs. The solutions are designed for real-time efficiency, scalability, and strong security. A primary contribution is the development of a localized task management system that significantly reduces authentication latency in centralized VANETs, achieving vehicle verification within a fraction of a millisecond. In decentralized settings, the proposed protocols employ advanced cryptographic mechanisms to establish distributed trust without incurring high computational overhead, including elliptic curve digital signatures (ECDSA) and non-interactive zero-knowledge proofs (NIZKPs). These techniques provide strong, provable security while preserving user anonymity during authentication and message exchange. To enhance group communication in VANETs, the thesis introduces efficient group key-sharing schemes that support secure, direct interactions among vehicles. Furthermore, a novel localized revocation mechanism immediately removes malicious vehicles from the network, addressing a key limitation in existing frameworks. This ensures fast, secure authentication for time-sensitive message transfers while limiting the propagation of malicious data. The thesis also investigates the proposed protocol’s performance under dynamic conditions such as high traffic density, large-scale decentralized deployments, and remote authentication scenarios. It introduces an innovative batch verification technique that supports fault-tolerant Vehicle-to-Vehicle (V2V) authentication, capable of maintaining high throughput while accurately identifying faulty messages even when the invalid message rate reaches 42%. Empirical evaluations demonstrate that the proposed solutions outperform existing schemes in terms of latency, computational efficiency, and robustness. The protocols complete single vehicle verifications within 5 milliseconds, making them suitable for dense and time-critical VANET environments. Additionally, all proposed methods align with prevailing vehicular communication standards such as IEEE WAVE and 3GPP C-V2X, ensuring practical applicability. In summary, this research advances the state of the art in VANET security by delivering scalable, privacy-preserving, and efficient authentication protocols that meet the demands of real-time vehicular communication systems.Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 4 inskickat, delarbete 5 accepterat.At the time of the doctoral defence the following papers were unpublished: paper 4 submitted, paper 5 accepted.</p
Privacy-Preserved Authentication & Communication in Vehicular Ad-Hoc Networks
No full textAs a key component of Intelligent Transportation Systems (ITS), Vehicular Ad hoc Networks (VANETs) enable real-time data exchange, traffic optimization, and smarter mobility. However, large-scale deployment raises critical security and privacy concerns, including message integrity, user anonymity, and protection against unauthorized access. This thesis proposes lightweight cryptographic protocols for secure and privacy-preserving authentication in both centralized and decentralized VANETs. The solutions are designed for real-time efficiency, scalability, and strong security. A primary contribution is the development of a localized task management system that significantly reduces authentication latency in centralized VANETs, achieving vehicle verification within a fraction of a millisecond. In decentralized settings, the proposed protocols employ advanced cryptographic mechanisms to establish distributed trust without incurring high computational overhead, including elliptic curve digital signatures (ECDSA) and non-interactive zero-knowledge proofs (NIZKPs). These techniques provide strong, provable security while preserving user anonymity during authentication and message exchange. To enhance group communication in VANETs, the thesis introduces efficient group key-sharing schemes that support secure, direct interactions among vehicles. Furthermore, a novel localized revocation mechanism immediately removes malicious vehicles from the network, addressing a key limitation in existing frameworks. This ensures fast, secure authentication for time-sensitive message transfers while limiting the propagation of malicious data. The thesis also investigates the proposed protocol’s performance under dynamic conditions such as high traffic density, large-scale decentralized deployments, and remote authentication scenarios. It introduces an innovative batch verification technique that supports fault-tolerant Vehicle-to-Vehicle (V2V) authentication, capable of maintaining high throughput while accurately identifying faulty messages even when the invalid message rate reaches 42%. Empirical evaluations demonstrate that the proposed solutions outperform existing schemes in terms of latency, computational efficiency, and robustness. The protocols complete single vehicle verifications within 5 milliseconds, making them suitable for dense and time-critical VANET environments. Additionally, all proposed methods align with prevailing vehicular communication standards such as IEEE WAVE and 3GPP C-V2X, ensuring practical applicability. In summary, this research advances the state of the art in VANET security by delivering scalable, privacy-preserving, and efficient authentication protocols that meet the demands of real-time vehicular communication systems.Vid tidpunkten för disputationen var följande delarbeten opublicerade: delarbete 4 inskickat, delarbete 5 accepterat.At the time of the doctoral defence the following papers were unpublished: paper 4 submitted, paper 5 accepted.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
A Scheme for Distributed Vehicle Authentication and Revocation in Decentralized VANETs
No full textVehicular Ad-Hoc Networks (VANETs) offer enhanced road safety, efficient traffic management, and improved vehicle connectivity while dealing with privacy and security challenges in public communication. In these networks, authentication mechanisms are mandatory to establish trust among communicating entities, such as vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I), without losing identity and location-based privacy. The prevailing conventional authentication mechanisms frequently depend on a centralized trust authority (CA) to ensure the mutual verifiability of transmitted messages. Nevertheless, in scenarios where the density of vehicles within the network is notably high, an overwhelming influx of authentication requests may result in a communication bottleneck at the CA, leading to a single point of failure. This paper proposes a novel distributed authentication scheme in a decentralized VANET with multiple independent CAs connected to multiple local inspectors to eliminate a single point of failure. Furthermore, prior solutions lack the capability to immediately revoke a disputed vehicle that is transmitting malicious messages in the network. In this regard, the proposed scheme also facilitates an immediate revocation of a disputed sender to prevent other vehicles from further receiving malicious messages. As vehicles share time-sensitive data for driving assistance, our scheme minimizes the computation and communication costs for V2I key sharing and direct V2V authenticated message sharing significantly compared to previously proposed schemes. Using comparatively lightweight elliptic curve cryptography and eliminating the direct involvement of CAs in the authentication process, we have reduced the overall delays and achieved a maximum of ≈ 3.9 times faster V2I authenticated key sharing, and a maximum of ≈ 7.5 times faster V2V message sharing compared to state-of-the-art bilinear pairing-based protocols. A comprehensive efficiency analysis validates our scheme's ability to outperform time-sensitive responses, such as sending and receiving an alert within nearly 4 milliseconds.
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
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