Spectral Signatures in Backdoor Attacks

A recent line of work has uncovered a new form of data poisoning: so-called \emph{backdoor} attacks. These attacks are particularly dangerous because they do not affect a network's behavior on typical, benign data. Rather, the network only deviates from its expected output when triggered by a perturbation planted by an adversary. In this paper, we identify a new property of all known backdoor attacks, which we call \emph{spectral signatures}. This property allows us to utilize tools from robust statistics to thwart the attacks. We demonstrate the efficacy of these signatures in detecting and removing poisoned examples on real image sets and state of the art neural network architectures. We believe that understanding spectral signatures is a crucial first step towards designing ML systems secure against such backdoor attacksComment: 16 pages, accepted to NIPS 201

Redox Properties of Silver Nanoparticles

In this study, we use cyclic voltammetry to measure how nanoparticles would affect the redox potential of various electron transfer mediators (ETMs). The main class of ETMs tested was quinones, and the working electrode was decorated with gold nanoparticles. ETMs are major players in regulating redox processes in aquatic environments, and contamination of these aquatic systems with nanoparticles could drastically change these redox processes. To see if there is a difference in redox potential, we compared redox potentials between bare glassy carbon electrode, indium tin oxide (ITO) electrodes with a polycyclic aromatic hydrocarbon (PAH) layer, which was used to attach nanoparticles, and indium tin oxide electrodes with both PAH and gold nanoparticles. We find that on bare glassy carbon electrode, the redox potential was -0.005 V, ITO electrode with PAH surface had a redox potential of -0.004 V and an ITO electrode with PAH and gold nanoparticles had a redox potential of -0.067 V. As each layer is added, electrocatalysis increases and redox processes become more reversible, showing that gold nanoparticles have an electrocatalytic effect on ETMs

When and Why Consumers Respond to Online Privacy Violations

As consumer privacy concerns become paramount, it is increasingly critical to understand what constitutes a privacy violation and how consumers respond. Using a multi-method approach, this research shows that consumers perceive three privacy violation types with increasing levels of severity, explaining when and why consumers exhibit seemingly paradoxical responses to different violation types. Our theorizing and findings suggest that resource control is the predominant mechanism driving privacy behavior, and that situation controllability (operationalized as level of variability of privacy practices within the industry) may moderate its effects. ***Disclosure: An earlier version of this work was submitted and accepted to HICSS last year but was later withdrawn as the authors were unable to attend the conference due to extenuating circumstances. Thanks to the reviews provided by the conference committee last year, we were able to revise and update new analyses and studies in our empirical package in this submission

CDAOStore: A Phylogenetic Repository Using Logic Programming and Web Services

The CDAOStore is a portal aimed at facilitating the storage and retrieval of data and metadata associated to studies in the field of evolutionary biology and phylogenetic analysis. The novelty of CDAOStore lies in the use of a semantic-based approach to the storage and querying of data. This enables CDAOStore to overcome the data format restrictions and complexities of other repositories (e.g., TreeBase) and to provide a domain-specific query interface, derived from studies of querying requirements for phylogenetic databases. CDAOStore represents the first full implementation of the EvoIO stack, an inter-operation stack composed of a formal ontology (the Comparative Data Analysis Ontology), an XML exchange format (NeXML), and a web services API (PhyloWS). CDAOStore has been implemented on top of an RDF triple store, using a combination of standard web technologies and logic programming technology. In particular, we employed Prolog to support some of the format transformation tasks and, more importantly, in the implementation of several of the domain-specific queries, whose structure is beyond the reach of standard RDF query languages (e.g., SPARQL). CDAOStore is operational and it already hosts over 90 million RDF triples, imported from TreeBase or submitted by other domain scientists

Transcriptomic analysis of a 3D blood-brain barrier model exposed to disturbed fluid flow.

Cerebral aneurysms are more likely to form at bifurcations in the vasculature, where disturbed fluid is prevalent due to flow separation at sufficiently high Reynolds numbers. While previous studies have demonstrated that altered shear stress exerted by disturbed flow disrupts endothelial tight junctions, less is known about how these flow regimes alter gene expression in endothelial cells lining the blood-brain barrier. Specifically, the effect of disturbed flow on expression of genes associated with cell-cell and cell-matrix interaction, which likely mediate aneurysm formation, remains unclear. RNA sequencing of immortalized cerebral endothelial cells isolated from the lumen of a 3D blood-brain barrier model reveals distinct transcriptional changes in vessels exposed to fully developed and disturbed flow profiles applied by both steady and physiological waveforms. Differential gene expression, validated by qRT-PCR and western blotting, reveals that lumican, a small leucine-rich proteoglycan, is the most significantly downregulated gene in endothelial cells exposed to steady, disturbed flow. Knocking down lumican expression reduces barrier function in the presence of steady, fully developed flow. Moreover, adding purified lumican into the hydrogel of the 3D blood-brain barrier model recovers barrier function in the region exposed to fully developed flow. Overall, these findings emphasize the importance of flow regimes exhibiting spatial and temporal heterogeneous shear stress profiles on cell-matrix interaction in endothelial cells lining the blood-brain barrier, while also identifying lumican as a contributor to the formation and maintenance of an intact barrier

CDAO-Store: Ontology-driven Data Integration for Phylogenetic Analysis

<p>Abstract</p> <p>Background</p> <p>The <it>Comparative Data Analysis Ontology (CDAO) </it>is an ontology developed, as part of the EvoInfo and EvoIO groups supported by the National Evolutionary Synthesis Center, to provide semantic descriptions of data and transformations commonly found in the domain of phylogenetic analysis. The core concepts of the ontology enable the description of phylogenetic trees and associated character data matrices.</p> <p>Results</p> <p>Using CDAO as the semantic back-end, we developed a triple-store, named <it>CDAO</it>-<it>Store</it>. CDAO-Store is a RDF-based store of phylogenetic data, including a complete import of TreeBASE. CDAO-Store provides a programmatic interface, in the form of web services, and a web-based front-end, to perform both user-defined as well as domain-specific queries; domain-specific queries include search for nearest common ancestors, minimum spanning clades, filter multiple trees in the store by size, author, taxa, tree identifier, algorithm or method. In addition, CDAO-Store provides a visualization front-end, called <it>CDAO</it>-<it>Explorer</it>, which can be used to view both character data matrices and trees extracted from the CDAO-Store. CDAO-Store provides import capabilities, enabling the addition of new data to the triple-store; files in PHYLIP, MEGA, <monospace>nexml</monospace>, and NEXUS formats can be imported and their CDAO representations added to the triple-store.</p> <p>Conclusions</p> <p>CDAO-Store is made up of a versatile and integrated set of tools to support phylogenetic analysis. To the best of our knowledge, CDAO-Store is the first semantically-aware repository of phylogenetic data with domain-specific querying capabilities. The portal to CDAO-Store is available at <url>http://www.cs.nmsu.edu/~cdaostore</url>.</p