926 research outputs found
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A novel word-independent gesture-typing continuous authentication scheme for mobile devices
In this study, we produce a new continuous authentication scheme for gesture-typing on mobile devices. Our scheme is the first scheme that authenticates gesture-typing interactions in a word-independent format. The scheme relies on groupings of features extracted from the word gesture after it has been reduced to parts common to all gestures. We show that movement sensors are also important in differentiating between users. We describe the feature extraction processes and analyse our proposed feature set. The unique process of our authentication scheme is presented and described. We collect our own gesture typing dataset including data collected during sitting, standing and walking activities for realism. We test our features against state-of-the-art touch-screen interaction features and compare feature extraction times on real mobile devices. Our scheme authenticates users with an equal error rate of 3.58% for a single word-gesture. The equal error rate is reduced to 0.81% when 3 word-gestures are used to authenticate
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Adaptive threshold scheme for touchscreen gesture continuous authentication using sensor trust
In this study we produce a continuous authentication scheme for mobile devices that adjusts an adaptive threshold for touchscreen interactions based on trust in passively collected sensor data. Our framework unobtrusively compares real-time sensor data of a user to historic data and adjusts a trust parameter based on the similarity. We show that the trust parameter can be used to adjust an adaptive threshold in continuous authentication schemes. The framework passively models temporal, spatial and activity scenarios using sensor data such as location, surrounding devices, wi-fi networks, ambient noise, movements, user activity, ambient light, proximity to objects and atmospheric pressure from study participants. Deviations from the models increases the level of threat the device perceives from the scenario. We also model the user touchscreen interactions. The touchscreen interactions are authenticated against a threshold that is continually adjusted based on the perceived trust. This scheme provides greater nuance between security and usability, enabling more refined decisions. We present our novel framework and threshold adjustment criteria and validate our framework on two state-of-the-art sensor datasets. Our framework more than halves the false acceptance and false rejection rates of a static threshold system
Competition in UK Electricity markets
This article includes information relating to competition in the UK electricity market, formerly published as part of UK Energy Sector Indicators. The article examines the two parts of the industry where there is competition for provision: generation and sales. For both markets, the article describes the number of companies operating, and the market concentrations. The Herfindahl-Hirschman measure (see explanation at the end of this article) is used to provide the market concentration as it provides extra emphasis on the contribution of participants with the largest shares. For electricity sales, this article covers the major suppliers1 surveyed by BEIS comprising approximately 96% of the market
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A novel scheme to address the fusion uncertainty in multi-modal continuous authentication schemes on mobile devices
Interest in continuous mobile authentication schemes has increased in recent years. These schemes use sensors on mobile devices to collect the biometric data about a user. The use of multiple sensors in a multi-modal scheme has been shown to improve the accuracy. However, sensor scores are often combined using simplistic techniques such as averaging. To date, the effect of uncertainty in score fusion has not been explored. In this paper, we present a novel Dempster-Shafer based score fusion approach for continuous authentication schemes. Our approach combines the sensor scores factoring in the uncertainty of the sensor. We propose and evaluate five techniques for computing uncertainty. Our proof-of-concept system is tested on three state-of-the-art datasets and compared with common fusion techniques. We find that our proposed approach yields the highest accuracies compared to the other fusion techniques and achieves equal error rates as low as 8.05%
Investigating the roles of arabidopsis polycomb-group genes in regulating flowering time and during plant development by (I) challenging silencing and (II) developing approaches to dissect Pc-G action
Polycomb-group (Pc-G) proteins regulate homeotic gene silencing associated with the
repressive covalent histone modification, trimethylation of histone H3 lysine 27 (H3K27me3).
Pc-G mediated silencing is believed to remodel chromatin, rendering target genes
inaccessible to transcription factors. Pc-G mediated silencing might result in irreversible
changes in chromatin structure, however, there has been little analysis addressing whether
Pc-G mediated silencing is reversible. In this work we focused on CURLY LEAF (CLF), the
first Pc-G homologue discovered in Arabidopsis. CLF mediated repression of the floral
homeotic gene AGAMOUS (AG) was challenged during early and late leaf development. AG
was activated by the late leaf promoter, revealing that Pc-G mediated silencing can be
overcome in old leaves in the presence of CLF. AG was also activated in young leaf
primordia, yet did not persist in older leaves, revealing that transient activation of a Pc-G
target is not epigenetically stable. To address the mechanism of Pc-G action within an
endogenous environment, the histone dynamics at the APETALA1 (AP1) locus were
characterized by Chromatin Immunoprecipitation. Unexpectedly, we found that the activation
of AP1 in leaves did not require the removal of H3K27me3, questioning whether H3K27me3
is sufficient to silence. The roles of CLF in leaf and flower development are masked due to partial redundancy with
SWINGER (SWN). clf- swn- mutants form a callus-like mass on sterile-tissue culture with no
distinguishable plant organs. The role of CLF in regulating flowering time in natural
populations of A. thaliana was investigated by complementing clf- mutants with CLF alleles
from two accessions. We found that natural variation in CLF did not affect flowering time. To
dissect the roles of CLF and SWN in late leaf and flower development, two approaches were
developed for targeted expression. Firstly, CLF was introduced into the LhG4/ pOp
transactivation system to provide CLF during early plant development. For mosaic analysis,
CLF was introduced into the CRE lox recombination system in order to create clf- sectors
surrounded by CLF+ SWN+ and CLF+ swn- cells
The effect of (Ti + Al): V ratio on the structure and oxidation behaviour of TiAlN/VN nano-scale multilayer coatings
Nano-scaled multilayered TiAlN/VN coatings have been grown on stainless steel and M2 high speed steel substrates at U-B = - 85 V in an industrial, four target, Hauzer HTC 1000 coater using combined cathodic steered arc etching/unbalanced magnetron sputtering. X-ray diffraction (XRD) has been used to investigate the effects of process parameters (Target Power) on texture evolution (using texture parameter T*), development of residual stress (sin(2) psi method) and nano-scale multilayer period. The composition of the coating was determined using energy dispersive X-ray analysis. The thermal behaviour of the coatings in air was studied using thermo-gravimetric analysis, XRD and scanning electron microscopy. The bi-layer period varied between 2.8 and 3.1 nm and in all cases a {1 1 0} texture developed with a maximum value T* = 4.9. The residual stress varied between -5.2 and -7.4 GPa. The onset of rapid oxidation occurred between 628 and 645 degreesC depending on the (Ti+Al):V ratio. After oxidation in air at 550 degreesC AlVO4, TiO2 and V2O5 Phases were identified by XRD with the AlVO4, TiO2 being the major phases. The formation of AlVO4 appears to disrupt the formation of Al2O3 which imparts oxidation resistance to TiAlN based coatings. Increasing the temperature to 600 and 640 degreesC led to a dramatic increase in the formation of V2O5 which was highly oriented (0 0 1) with a plate-like morphology. At 640 degreesC there was no evidence of the coating on XRD. Increasing the temperature to 670 degreesC led to further formation of AlVO4 and a dramatic reduction in V2O5. (C) 2003 Elsevier B.V. All rights reserved
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A Decentralized IIoT Identity Framework based on Self-Sovereign Identity using Blockchain
The fundamental requirement for interaction between digital entities is a secure and privacy-preserving digital identity infrastructure. Traditional approaches rely heavily on centralized architectural components such as Certificate Authorities (CAs) and credential storage databases that have drawbacks like a single point of failure, attack prone honeypot databases and poor scalability. Self-Sovereign Identity (SSI) is a novel decentralized digital identity model that uses Decentralized Identifiers (DIDs) and Verifiable Credentials (VCs). In this work, we propose a novel decentralized identity framework for Industrial Internet-of-Things (IIoT) based on SSI model. The proposed framework is implemented on two blockchain platforms namely Ethereum and Hyperledger Indy to study the underlying overheads
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