644 research outputs found
Credential hardening by using touchstroke dynamics
Today, reliance on digital devices for daily routines has been shifted towards portable mobile devices. Therefore, the need for security enhancements within this platform is imminent. Numerous research works have been performed on strengthening password authentication by using keystroke dynamics biometrics, which involve computer keyboards and cellular phones as input devices. Nevertheless, experiments performed specifically on touch screen devices are relatively lacking. This paper describes a novel technique to strengthen security authentication systems on touch screen devices via a new sub variant behavioural biometrics called touchstroke dynamics. We capitalize on the high resolution timing latency and the pressure information on touch screen panel as feature data. Following this a light weight algorithm is introduced to calculate the similarity between feature vectors. In addition, a fusion approach is proposed to enhance the overall performance of the system to an equal error rate of 7.71% (short input) and 6.27% (long input)
Transport properties of a holographic model with novel gauge-axion coupling
We investigate the transport properties within a holographic model
characterized by a novel gauge-axion coupling. A key innovation is the
introduction of the direct coupling between axion fields, the antisymmetric
tensor, and the gauge field in our bulk theory. This novel coupling term leads
to the emergence of non-diagonal components in the conductivity tensor. An
important characteristic is that the off-diagonal elements manifest
antisymmetry. Remarkably, the conductivity behavior in this model akin to that
of Hall conductivity. Additionally, this model can also achieve metal-insulator
transition.Comment: 28 pages, 11 figures, References adde
Physical Adsorption of Graphene Oxide onto Polymer Latexes and Characterization of the Resulting Nanocomposite Particles
[Image: see text] Polymer/graphene oxide (GO) nanocomposite particles were prepared via heteroflocculation between 140ā220 nm cationic latex nanoparticles and anionic GO nanosheets in either acidic or basic conditions. It is demonstrated that nanocomposite particles can be formed using either poly(2-vinylpyridine)-b-poly(benzyl methacrylate) (P2VPāPBzMA) block copolymer nanoparticles prepared by reversible-addition chain-transfer (RAFT)-mediated polymerization-induced self-assembly (PISA), or poly(ethylene glycol)methacrylate (PEGMA)-stabilized P2VP latexes prepared by traditional emulsion polymerization. These two latexes are different morphologically as the P2VPāPBzMA block copolymer latexes have P2VP steric stabilizer chains in their corona, whereas the PEGMA-stabilized P2VP particles have a P2VP core and a nonionic steric stabilizer. Nevertheless, both the P2VPāPBzMA and PEGMA-stabilized P2VP latexes are cationic at low pH. Thus, the addition of GO to these latexes causes flocculation to occur immediately due to the opposite charges between the anionic GO nanosheets and cationic latexes. Control heteroflocculation experiments were conducted using anionic sterically stabilized poly(potassium 3-sulfopropyl methacrylate)-b-poly(benzyl methacrylate) (PKSPMAāPBzMA) and nonionic poly(benzyl methacrylate) (PBzMA) nanoparticles to demonstrate that polymer/GO nanocomposite particles were not formed. The degree of flocculation and the strength of electrostatic interaction between the cationic polymer latexes and GO were assessed using disc centrifuge photosedimentometry (DCP), transmission electron microscopy (TEM), and UVāvisible spectrophotometry. These studies suggest that the optimal conditions for the formation of polymer/GO nanocomposite particles were GO contents between 10% and 20% w/w relative to latex, with the latexes containing P2VP in their corona having a stronger electrostatic attraction to the GO sheets
Recommended from our members
A Robust Gene Expression Prognostic Signature for Overall Survival in High-Grade Serous Ovarian Cancer.
The objective of this research was to develop a robust gene expression-based prognostic signature and scoring system for predicting overall survival (OS) of patients with high-grade serous ovarian cancer (HGSOC). Transcriptomic data of HGSOC patients were obtained from six independent studies in the NCBI GEO database. Genes significantly deregulated and associated with OS in HGSOCs were selected using GEO2R and Kaplan-Meier analysis with log-rank testing, respectively. Enrichment analysis for biological processes and pathways was performed using Gene Ontology analysis. A resampling/cross-validation method with Cox regression analysis was used to identify a novel gene expression-based signature associated with OS, and a prognostic scoring system was developed and further validated in nine independent HGSOC datasets. We first identified 488 significantly deregulated genes in HGSOC patients, of which 232 were found to be significantly associated with their OS. These genes were significantly enriched for cell cycle division, epithelial cell differentiation, p53 signaling pathway, vasculature development, and other processes. A novel 11-gene prognostic signature was identified and a prognostic scoring system was developed, which robustly predicted OS in HGSOC patients in 100 sampling test sets. The scoring system was further validated successfully in nine additional HGSOC public datasets. In conclusion, our integrative bioinformatics study combining transcriptomic and clinical data established an 11-gene prognostic signature for robust and reproducible prediction of OS in HGSOC patients. This signature could be of clinical value for guiding therapeutic selection and individualized treatment
On quasinormal frequencies of black hole perturbations with an external source
In the study of perturbations around black hole configurations, whether an
external source can influence the perturbation behavior is an interesting topic
to investigate. When the source acts as an initial pulse, it is intuitively
acceptable that the existing quasinormal frequencies will remain unchanged.
However, the confirmation of such an intuition is not trivial for the rotating
black hole, since the eigenvalues in the radial and angular parts of the master
equations are coupled. We show that for the rotating black holes, a moderate
source term in the master equation in the Laplace s-domain does not modify the
quasinormal modes. Furthermore, we generalize our discussions to the case where
the external source serves as a driving force. Different from an initial pulse,
an external source may further drive the system to experience new perturbation
modes. To be specific, novel dissipative singularities might be brought into
existence and enrich the pole structure. This is a physically relevant
scenario, due to its possible implication in modified gravity. Our arguments
are based on exploring the pole structure of the solution in the Laplace
s-domain with the presence of the external source. The analytical analyses are
verified numerically by solving the inhomogeneous differential equation and
extracting the dominant complex frequencies by employing the Prony method.Comment: 17 pages, 3 figures, accepted for publication on EPJ
- ā¦