Principles for increased resilience in critical networked infrastructures

We propose a framework for deploying stronger, intelligent resilience mechanisms in mission-critical ATM networks over and above that offered by physical n-fold redundancy. We compare the challenges facing power and data network resilience and discuss disruptive threats to real-world operations. Using recorded live data from an ATM data network we argue our proposed architecture with deployable, distributed on-demand anomaly detection and monitoring modules provides enhanced fail-secure versus current fail-safe resilience

Construction of a human torso model from magnetic resonance images for problems in computational electrocardiography

Journal ArticleApplying mathematical models to real situations often requires the use of discrete geometrical models of the solution domain. In some cases destructive measurement of the objects under examination is acceptable, but in biomedical applications the measurements come from imaging techniques such as X-ray, computer tomography (CT), or magnetic resonance imagining (MRI). A necessary early step in the modeling process is then to extract from these images the measurements (locations and distances) that form the basis of the geometrical model. In this paper we describe the construction of a geometrical model of the human thorax based on the high resolution MRI scan of a single subject. We outline the scanning procedure, the image collection and conversion to computerized image files, the segmentation of the images into boundary nodes, and the connection of these nodes into surface, and then volume, meshes. Included are brief descriptions of the tools developed at the CVRTI for this project, as well as our experiences in creating and using them. The result of this work was a pair of models at two different levels of spatial resolution, which set new standards in the area of bioelectric field modeling and the application of these models has been described previously [1, 2]

Another Extremal Property of Some Turan Graphs

An inequality relating the size and order of a simple graph to the average number of triangles containing a fixed edge is proven. It is shown that the only graphs for which equality holds in this inequality are the Turin graphs with the same number of vertices in each partite set

MRI: Acquisition of an SEM-EDS-EBSD-CL Microanalytical System for Solid Earth and Climate Change Research

Funding from the Major Research Instrumentation (MRI) Program grant will support acquisition of an Scanning Electron Microscope with secondary and backscattered electron detectors, electron backscatter diffraction capability, and live-color cathodluminescence capability for the Department of Earth Sciences at the University of Maine. The instrument will be used to support faculty and student research in geodynamics and crustal studies and studies of global climate change. The instrument will be the primary research tool of an early career researcher, but will be utilized by several faculty within the department. The scanning electron microscope facility is unique within the state of Maine and will thus operate as a regional facility for research collaboration with scientists from other universities, state government agencies, such as the Maine Geological Survey, and private industry. The facility and its personnel will also participate in outreach activities for K-12 education and the Penobscot Indian Nation

Layer-thickness dependence of the conductive properties of Mo/Si multilayers

We report new measurements of the conductance and superconducting transition temperature of a set of Mo/Si multilayers, as a function of the metal layer thickness (from 7-85 Angstrom) for a constant semiconductor layer thickness of 22 Angstrom. Unlike previously reported measurements, we do not observe oscillations in either the resistivity, resistivity ratio, or the superconducting transition temperature with the metal layer thickness. Rather, we observe monotonic variations in the transport properties as the metal layer thickness increases. The sheet conductance and its change between 10 and 300 K both vary approximately linearly with the metal layer thickness, above a threshold thickness. The conductance starts to grow with metal layer thickness at approximately 10 Angstrom, whereas the temperature coefficient of resistance changes sign at approximately 25 Angstrom, exhibiting a Mooij correlation with a crossover resistivity of 125 mu Omega cm. The observed temperature dependence of the conductance rules out localization as the origin of the negative temperature coefficient of resistance. The conductance data are analyzed using a simple phenomenological model involving transport in interfacial and metallic layers, whose relative contribution to the conductance depends on the metal layer thickness and the temperature. The model is applied to separate two competing contributions that determine the overall temperature dependence of the conductance. We attribute the differences between our measurements and previous measurements to differences in bulk metallic conductivities and interface morphologies, due to differences in thermal evaporation versus sputtering fabrication processes. Our results show that the level and nature of disorder is an important ingredient in any theory that explains the cause of the observed oscillations

Uncivil behaviour in the workplace causes mental fatigue and is contagious

Employees on the receiving end tend to ‘pay forward’ the incivility to others, write Christopher C. Rosen, Joel Koopman, Allison S. Gabriel and Russell E. Johnso

Fewer Flops at the Top: Accuracy, Diversity, and Regularization in Two-Class Collaborative Filtering

In most existing recommender systems, implicit or explicit interactions are treated as positive links and all unknown interactions are treated as negative links. The goal is to suggest new links that will be perceived as positive by users. However, as signed social networks and newer content services become common, it is important to distinguish between positive and negative preferences. Even in existing applications, the cost of a negative recommendation could be high when people are looking for new jobs, friends, or places to live. In this work, we develop novel probabilistic latent factor models to recommend positive links and compare them with existing methods on five different openly available datasets. Our models are able to produce better ranking lists and are effective in the task of ranking positive links at the top, with fewer negative links (flops). Moreover, we find that modeling signed social networks and user preferences this way has the advantage of increasing the diversity of recommendations. We also investigate the effect of regularization on the quality of recommendations, a matter that has not received enough attention in the literature. We find that regularization parameter heavily affects the quality of recommendations in terms of both accuracy and diversity

Land Conservation in the Northeastern United States: An Assessment of Historic Trends and Current Conditions

This article discusses the evolution of land conservation efforts and outcomes in the Northeast, examine major drivers of landscape change, and review key conservation tools that have been used to protect public values at the local and landscape levels. We then assess the current status of land conservation, and draw lessons for other regions facing conservation challenges across mixed ownership landscapes under varying development and land-use pressures. Finally, we explore new and emerging trends in the factors driving land development and conservation activities in an effort to assess the challenges that lie ahead

Convergent Evolution of Brain Morphology and Communication Modalities in Lizards

Animals communicate information within their environments via visual, chemical, auditory, and/or tactile modalities. The use of each modality is generally linked to particular brain regions, but it is not yet known whether the cellular morphology of neurons in these regions has evolved in association with the relative use of a modality. We investigated relationships between the behavioral use of communication modalities and neural morphologies in six lizard species. Two of these species (Anolis carolinensis and Leiocephalus carinatus) primarily use visual signals to communicate with conspecifics and detect potential prey, and two (Aspidoscelis gularis and Scincella lateralis) communicate and forage primarily using chemical signals. Two other species (Hemidactylus turcicus and Sceloporus olivaceus) use both visual and chemical signals. For each species, we performed behavioral observations and quantified rates of visual and chemical behaviors. We then cryosectioned brain tissues from 9-10 males of each species and measured the soma size and density of neurons in two brain regions associated with visual behaviors (the lateral geniculate nucleus and the nucleus rotundus) and one region associated with chemical behaviors (the nucleus sphericus). With analyses conducted in a phylogenetic context, we found that species that performed higher rates of visual displays had a denser lateral geniculate nucleus, and species that used a higher proportion of chemical displays had larger somas in the nucleus sphericus. These relationships suggest that neural morphologies in the brain have evolved convergently in species with similar communication behaviors