906 research outputs found

    Application and evaluation of the RF charge-pumping technique

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    In this paper, we will discuss the extendibility of the charge-pumping (CP) technique toward frequencies up to 4 GHz. Such high frequencies are attractive when a significant gate leakage current flows, obscuring the CP current at lower pumping frequencies.\ud It is shown that using RF gate excitation, accurate CP curves can be obtained on MOS devices with a leakage current density exceeding 1 A•cm−2 . A theoretical analysis of the trap response to RF gate voltage signals is presented, giving a clear insight on the benefits and limitations of the technique.\u

    Asset-Oriented Access Control: Towards a New IoT Framework

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    Controlling asset-access has traditionally been considered a matter for systems in which assets reside. Centralized approaches to access control are, however, problematic for the IoT. One reason for this is that devices may not be confined to a single system of control. In this abstract, we argue for a new paradigm in which assets are empowered to make their own access decisions. To facilitate this shift in perspective, we propose a policy-neutral framework based on principles adapted from object-oriented programming. This approach establishes assets as active, message-passing entities that store and determine their own access control. We describe initial work modelling the interaction of such assets and point to future formal work for reasoning about protocols and policy composition

    Vertebrate Natural History Notes from Arkansas, 2017

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    Because meaningful observations of natural history are not always part of larger studies, important pieces of information often are unreported. Small details, however, can fills gaps in understanding and also lead to interesting questions about ecological relationships or environmental change. We have compiled recent observations of foods, reproduction, record size, parasites, and distribution of 30 species of fishes, new records of distribution and parasites of 2 species of amphibians, and new records of distribution, parasites, reproduction and anomalies of 11 species of mammals

    Considering the User in the Wireless World

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    The near future promises significant advances in communication capabilities, but one of the keys to success is the capability understanding of the people with regards to its value and usage. In considering the role of the user in the wireless world of the future, the Human Perspective Working Group (WG1) of the Wireless World Research Forum has gathered input and developed positions in four important areas: methods, processes, and best practices for user-centered research and design; reference frameworks for modeling user needs within the context of wireless systems; user scenario creation and analysis; and user interaction technologies. This article provides an overview of WG1's work in these areas that are critical to ensuring that the future wireless world meets and exceeds the expectations of people in the coming decades

    Electronic Footprints in the Sand: Technologies for Assisting Domestic Violence Survivors

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    With the rapid growth and spread of Internet-based social support systems, the impact that these systems can make to society – be it good or bad – has become more significant and can make a real difference to people’s lives. As such, various aspects of these systems need to be carefully investigated and analysed, including their security/privacy issues. In this paper, we present our work in designing and implementing various technological features that can be used to assist domestic violence survivors in obtaining help without leaving traces which might lead to further violence from their abuser. This case study serves as the core of our paper, in which we outline our approach, various de- sign considerations – including difficulties in keeping browsing history private, our currently implemented solutions (single use URL, targeted history sanitita- tion agent, and secret graphical gateway), as well as novel ideas for future work (including location-based service advertising and deployment in the wild)

    A neural network-based estimate of the seasonal to inter-annual variability of the Atlantic Ocean carbon sink

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    The Atlantic Ocean is one of the most important sinks for atmospheric carbon dioxide (CO2), but this sink has been shown to vary substantially in time. Here we use surface ocean CO2 observations to estimate this sink and the temporal variability from 1998 through 2007 in the Atlantic Ocean. We benefit from (i) a continuous improvement of the observations, i.e. the Surface Ocean CO2 Atlas (SOCAT) v1.5 database and (ii) a newly developed technique to interpolate the observations in space and time. In particular, we use a two-step neural network approach to reconstruct basin-wide monthly maps of the sea surface partial pressure of CO2 (pCO2) at a resolution of 1° × 1°. From those, we compute the air–sea CO2 flux maps using a standard gas exchange parameterization and high-resolution wind speeds. The neural networks fit the observed pCO2 data with a root mean square error (RMSE) of about 10 μatm and with almost no bias. A check against independent time-series data and new data from SOCAT v2 reveals a larger RMSE of 22.8 μatm for the entire Atlantic Ocean, which decreases to 16.3 μatm for data south of 40° N. We estimate a decadal mean uptake flux of −0.45 ± 0.15 Pg C yr−1 for the Atlantic between 44° S and 79° N, representing the sum of a strong uptake north of 18° N (−0.39 ± 0.10 Pg C yr−1), outgassing in the tropics (18° S–18° N, 0.11 ± 0.07 Pg C yr−1), and uptake in the subtropical/temperate South Atlantic south of 18° S (−0.16 ± 0.06 Pg C yr−1), consistent with recent studies. The strongest seasonal variability of the CO2 flux occurs in the temperature-driven subtropical North Atlantic, with uptake in winter and outgassing in summer. The seasonal cycle is antiphased in the subpolar latitudes relative to the subtropics largely as a result of the biologically driven winter-to-summer drawdown of CO2. Over the 10 yr analysis period (1998 through 2007), sea surface pCO2 increased faster than that of the atmosphere in large areas poleward of 40° N, while in other regions of the North Atlantic the sea surface pCO2 increased at a slower rate, resulting in a barely changing Atlantic carbon sink north of the Equator (−0.01 ± 0.02 Pg C yr−1 decade−1). Surface ocean pCO2 increased at a slower rate relative to atmospheric CO2 over most of the Atlantic south of the Equator, leading to a substantial trend toward a stronger CO2 sink for the entire South Atlantic (−0.14 ± 0.02 Pg C yr−1 decade−1). In contrast to the 10 yr trends, the Atlantic Ocean carbon sink varies relatively little on inter-annual timescales (±0.04 Pg C yr−1; 1 σ)

    Vertebrate Natural History Notes from Arkansas, 2018

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    Because meaningful observations of natural history are not always part of larger studies, important pieces of information often are unreported. Small details, however, can fill gaps in understanding and lead to interesting questions about ecological relationships or environmental change. We have compiled recent important observations of distribution, deformities, and foods of various vertebrates, observations of winter activity of a woodchuck (Marmota monax) and winter torpor of a hoary bat (Lasiurus cinereus), and also report a very unusual case of bilateral gynandromorphism in a Cardinal (Cardinalis cardinalis). These unique observations continue to add immensely to the growth of knowledge of the biology of vertebrates in Arkansas
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