6,361 research outputs found
Your WiFi is leaking: what do your mobile apps gossip about you?
This paper describes how mobile device apps can inadvertently broadcast personal information through their use of wireless networks despite the correct use of encryption. Using a selection of personas we illustrate how app usage can be tied to personal information. Users would likely assume the confidentiality of personal information (including age, religion, sexuality and gender) when using an encrypted network. However, we demonstrate how encrypted traffic pattern analysis can allow a remote observer to infer potentially sensitive data passively and undetectably without any network credentials. Without the ability to read encrypted WiFi traffic directly, we process the limited side-channel data available (timings and frame sizes) to enable remote app detection. These side-channel data measurements are represented as histograms and used to construct a Random Forest classifier capable of accurately identifying mobile apps from the encrypted traffic they cause. The Random Forest algorithm was able to correctly identify apps with a mean accuracy of ∼99% within the training set. The classifier was then adapted to form the core of a detection program that could monitor multiple devices in real-time. Tests in a closed-world scenario showed 84% accuracy and demonstrated the ability to overcome the data limitations imposed by WiFi encryption. Although accuracy suffers greatly (67%) when moving to an open-world scenario, a high recall rate of 86% demonstrates that apps can unwittingly broadcast personal information openly despite using encrypted WiFi. The open-world false positive rate (38% overall, or 72% for unseen activity alone) leaves much room for improvement but the experiment demonstrates a plausible threat nevertheless. Finally, avenues for improvement and the limitations of this approach are identified. We discuss potential applications, strategies to prevent these leaks, and consider the effort required for an observer to present a practical privacy threat to the everyday WiFi user. This paper presents and demonstrates a nuanced and difficult to solve privacy vulnerability that cannot not be mitigated without considerable changes to current- and next-generation wireless communication protocols
Ultra-fast early Miocene exhumation of Cavalli Seamount, Northland Plateau, Southwest Pacific Ocean
We present new photographic, petrological, geochronological, and isotopic data for gneissic and granitic rocks obtained from six sample stations on Cavalli Seamount during two cruises in 2002. These data lead to revision of earlier conclusions based on two dredges of schist in 1999. Based on c. 100 Ma ages of zircon cores, and whole rock petrochemistry and tracer isotopes, we interpret the protoliths of paragneisses and orthogneisses to probably have been sedimentary and plutonic correlatives of the Late Cretaceous Houhora Complex. U‐Pb dating of low Th/U zircon rims confirms an earliest Miocene high‐grade metamorphic episode. A cooling history based on Ar‐Ar K‐feldspar dating indicates ultra‐rapid cooling (c. 2000°C/m.y.) and vertical exhumation (c. 100 mm/yr) of the rocks at 19.9 Ma. Our preferred tectonic model relates the amphibolite facies metamorphism to Northland Allochthon emplacement and the rapid exhumation to dextral transtension along the Vening Meinesz Fracture Zone system and/or a rapidly retreating Pacific trench
Colored Non-Crossing Euclidean Steiner Forest
Given a set of -colored points in the plane, we consider the problem of
finding trees such that each tree connects all points of one color class,
no two trees cross, and the total edge length of the trees is minimized. For
, this is the well-known Euclidean Steiner tree problem. For general ,
a -approximation algorithm is known, where is the
Steiner ratio.
We present a PTAS for , a -approximation algorithm
for , and two approximation algorithms for general~, with ratios
and
Rapid generation of chromosome-specific alphoid DNA probes using the polymerase chain reaction
Non-isotopic in situ hybridization of chromosome-specific alphoid DNA probes has become a potent tool in the study of numerical aberrations of specific human chromosomes at all stages of the cell cycle. In this paper, we describe approaches for the rapid generation of such probes using the polymerase chain reaction (PCR), and demonstrate their chromosome specificity by fluorescence in situ hybridization to normal human metaphase spreads and interphase nuclei. Oligonucleotide primers for conserved regions of the alpha satellite monomer were used to generate chromosome-specific DNA probes from somatic hybrid cells containing various human chromosomes, and from DNA libraries from sorted human chromosomes. Oligonucleotide primers for chromosome-specific regions of the alpha satellite monomer were used to generate specific DNA probes for the pericentromeric heterochromatin of human chromosomes 1, 6, 7, 17 and X directly from human genomic DNA
Engaging Undergraduates in Science Research: Not Just About Faculty Willingness.
Despite the many benefits of involving undergraduates in research and the growing number of undergraduate research programs, few scholars have investigated the factors that affect faculty members' decisions to involve undergraduates in their research projects. We investigated the individual factors and institutional contexts that predict faculty members' likelihood of engaging undergraduates in their research project(s). Using data from the Higher Education Research Institute's 2007-2008 Faculty Survey, we employ hierarchical generalized linear modeling to analyze data from 4,832 science, technology, engineering, and mathematics (STEM) faculty across 194 institutions to examine how organizational citizenship behavior theory and social exchange theory relate to mentoring students in research. Key findings show that faculty who work in the life sciences and those who receive government funding for their research are more likely to involve undergraduates in their research project(s). In addition, faculty at liberal arts or historically Black colleges are significantly more likely to involve undergraduate students in research. Implications for advancing undergraduate research opportunities are discussed
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An Overview of the Use of Neural Networks for Data Mining Tasks
In the recent years the area of data mining has experienced a considerable demand for technologies that extract knowledge from large and complex data sources. There is a substantial commercial interest as well as research investigations in the area that aim to develop new and improved approaches for extracting information, relationships, and patterns from datasets. Artificial Neural Networks (NN) are popular biologically inspired intelligent methodologies, whose classification, prediction and pattern recognition capabilities have been utilised successfully in many areas, including science, engineering, medicine, business, banking, telecommunication, and many other fields. This paper highlights from a data mining perspective the implementation of NN, using supervised and unsupervised learning, for pattern recognition, classification, prediction and cluster analysis, and focuses the discussion on their usage in bioinformatics and financial data analysis tasks
Most vital segment barriers
We study continuous analogues of "vitality" for discrete network flows/paths,
and consider problems related to placing segment barriers that have highest
impact on a flow/path in a polygonal domain. This extends the graph-theoretic
notion of "most vital arcs" for flows/paths to geometric environments. We give
hardness results and efficient algorithms for various versions of the problem,
(almost) completely separating hard and polynomially-solvable cases
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The rise of the quasi-public space and its consequences for cities and culture
This article argues that whilst appearing new, quasi-public spaces have emerged from a process of investment restructuring over the last 50 years. The profound change that is set in motion is a loss of control of public space and its cultural uses in cities. The tensions set up in this transformation are illustrated by the cultural fortunes of the largest such space in London, Granary Square; and, that of the City of London that has little, if any, public space
Effects of deletion of the Streptococcus pneumoniae lipoprotein diacylglyceryl transferase gene lgt on ABC transporter function and on growth in vivo
Lipoproteins are an important class of surface associated proteins that have diverse roles and frequently are involved in the virulence of bacterial pathogens. As prolipoproteins are attached to the cell membrane by a single enzyme, prolipoprotein diacylglyceryl transferase (Lgt), deletion of the corresponding gene potentially allows the characterisation of the overall importance of lipoproteins for specific bacterial functions. We have used a Δlgt mutant strain of Streptococcus pneumoniae to investigate the effects of loss of lipoprotein attachment on cation acquisition, growth in media containing specific carbon sources, and virulence in different infection models. Immunoblots of triton X-114 extracts, flow cytometry and immuno-fluorescence microscopy confirmed the Δlgt mutant had markedly reduced lipoprotein expression on the cell surface. The Δlgt mutant had reduced growth in cation depleted medium, increased sensitivity to oxidative stress, reduced zinc uptake, and reduced intracellular levels of several cations. Doubling time of the Δlgt mutant was also increased slightly when grown in medium with glucose, raffinose and maltotriose as sole carbon sources. These multiple defects in cation and sugar ABC transporter function for the Δlgt mutant were associated with only slightly delayed growth in complete medium. However the Δlgt mutant had significantly reduced growth in blood or bronchoalveolar lavage fluid and a marked impairment in virulence in mouse models of nasopharyngeal colonisation, sepsis and pneumonia. These data suggest that for S. pneumoniae loss of surface localisation of lipoproteins has widespread effects on ABC transporter functions that collectively prevent the Δlgt mutant from establishing invasive infection
Socially sensitive lactation: Exploring the social context of breastfeeding
Many women report difficulties with breastfeeding and do not maintain the practice for as long as intended. Although psychologists and other researchers have explored some of the difficulties they experience, fuller exploration of the relational contexts in which breastfeeding takes place is warranted to enable more in-depth analysis of the challenges these pose for breastfeeding women. The present paper is based on qualitative data collected from 22 first-time breastfeeding mothers through two phases of interviews and audio-diaries which explored how the participants experienced their relationships with significant others and the wider social context of breastfeeding in the first five weeks postpartum. Using a thematic analysis informed by symbolic interactionism, we develop the overarching theme of ‘Practising socially sensitive lactation’ which captures how participants felt the need to manage tensions between breastfeeding and their perceptions of the needs, expectations and comfort of others. We argue that breastfeeding remains a problematic social act, despite its agreed importance for child health. Whilst acknowledging the limitations of our sample and analytic approach, we suggest ways in which perinatal and public health interventions can take more effective account of the social challenges of breastfeeding in order to facilitate the health and psychological well-being of mothers and their infants
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