The Feasibility of Dynamically Granted Permissions: Aligning Mobile Privacy with User Preferences

Current smartphone operating systems regulate application permissions by prompting users on an ask-on-first-use basis. Prior research has shown that this method is ineffective because it fails to account for context: the circumstances under which an application first requests access to data may be vastly different than the circumstances under which it subsequently requests access. We performed a longitudinal 131-person field study to analyze the contextuality behind user privacy decisions to regulate access to sensitive resources. We built a classifier to make privacy decisions on the user's behalf by detecting when context has changed and, when necessary, inferring privacy preferences based on the user's past decisions and behavior. Our goal is to automatically grant appropriate resource requests without further user intervention, deny inappropriate requests, and only prompt the user when the system is uncertain of the user's preferences. We show that our approach can accurately predict users' privacy decisions 96.8% of the time, which is a four-fold reduction in error rate compared to current systems.Comment: 17 pages, 4 figure

A novel wideband dynamic directional indoor channel model based on a Markov process

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A Static Analyzer for Large Safety-Critical Software

We show that abstract interpretation-based static program analysis can be made efficient and precise enough to formally verify a class of properties for a family of large programs with few or no false alarms. This is achieved by refinement of a general purpose static analyzer and later adaptation to particular programs of the family by the end-user through parametrization. This is applied to the proof of soundness of data manipulation operations at the machine level for periodic synchronous safety critical embedded software. The main novelties are the design principle of static analyzers by refinement and adaptation through parametrization, the symbolic manipulation of expressions to improve the precision of abstract transfer functions, the octagon, ellipsoid, and decision tree abstract domains, all with sound handling of rounding errors in floating point computations, widening strategies (with thresholds, delayed) and the automatic determination of the parameters (parametrized packing)

Computing Nash Equilibrium in Wireless Ad Hoc Networks: A Simulation-Based Approach

This paper studies the problem of computing Nash equilibrium in wireless networks modeled by Weighted Timed Automata. Such formalism comes together with a logic that can be used to describe complex features such as timed energy constraints. Our contribution is a method for solving this problem using Statistical Model Checking. The method has been implemented in UPPAAL model checker and has been applied to the analysis of Aloha CSMA/CD and IEEE 802.15.4 CSMA/CA protocols.Comment: In Proceedings IWIGP 2012, arXiv:1202.422

Construction and Performance of Large-Area Triple-GEM Prototypes for Future Upgrades of the CMS Forward Muon System

At present, part of the forward RPC muon system of the CMS detector at the CERN LHC remains uninstrumented in the high-\eta region. An international collaboration is investigating the possibility of covering the 1.6 < |\eta| < 2.4 region of the muon endcaps with large-area triple-GEM detectors. Given their good spatial resolution, high rate capability, and radiation hardness, these micro-pattern gas detectors are an appealing option for simultaneously enhancing muon tracking and triggering capabilities in a future upgrade of the CMS detector. A general overview of this feasibility study will be presented. The design and construction of small (10\times10 cm2) and full-size trapezoidal (1\times0.5 m2) triple-GEM prototypes will be described. During detector assembly, different techniques for stretching the GEM foils were tested. Results from measurements with x-rays and from test beam campaigns at the CERN SPS will be shown for the small and large prototypes. Preliminary simulation studies on the expected muon reconstruction and trigger performances of this proposed upgraded muon system will be reported.Comment: 7 pages, 25 figures, submitted for publication in conference record of the 2011 IEEE Nuclear Science Symposium, Valencia, Spai

Analysis and Control of a Cellular Converter System with Stochastic Ripple Cancellation and Minimal Magnetics

Abstract-A parallel converter architecture based on the resonant pole inverter (RPI) topology is presented. It is shown that this architecture minimizes the output magnetics required for current sharing. A new current control scheme is introduced which reduces peak currents, losses, and output voltage ripple for many operating conditions. This new control method is applicable to both the single RPI and the parallel architecture. Additionally, the paper analytically quantifies the degree of passive ripple cancellation between cells of a parallel architecture. It is shown that the rms ripple current of an N -cell paralleled converter system is a factor of 1= p N lower than for an equivalent single converter. These results are verified using a piecewise-linear model. We conclude that the parallel architecture overcomes some of the major disadvantages of the conventional RPI

Impact of Mechanical Stress on the Full Chip Timing for Through-Silicon-Via-based 3-D ICs

Abstract-In this paper, we study the impact of throughsilicon-via (TSV) and shallow trench isolation (STI) stress on the timing variations of 3-D IC. We also propose the first systematic TSV-STI-stress-aware timing analysis and show how to optimize layouts for better performance. First, we generate a stress contour map with an analytical radial stress model for TSV. We also develop a stress model for STI from finite element analysis results. Then, depending on geometric relation between TSVs, STI, and transistors, the tensile and compressive stresses are converted to hole and electron mobility variations. Mobility-variation-aware cell library and netlist are generated and incorporated into an industrial engine for timing analysis of 3-D IC. We observe that TSV stress and STI stress interact with each other, and rise and fall time react differently to stress and relative locations with respect to both TSVs and STIs. Overall, TSV-STI-stress-induced timing variations can be as much as ±15% at the cell level. Thus, as an application to layout optimization, we exploit the stress-induced mobility enhancement to improve performance of 3-D ICs. We show that stress-aware layout perturbation could reduce cell delay by up to 23.37% and critical path delay by 6.67% in our test case

FUTURE CONTROL TECHNOLOGIES IN MOTOR DIAGNOSTICS AND SYSTEM WELLNESS

Abstract -Over the past few years, industrial manufacturing disciplines have evolved from a strategy of routine scheduled maintenance of electrical equipment to Condition Based Maintenance (CBM). In the CBM approach, equipment maintenance based on a routine schedule can be replaced with an approach based on system wellness diagnostics. This approach might rely on non-invasive monitoring of three-phase induction motors to report equipment condition and enable maintenance intervention before a failure occurs. Recent research conducted at the University of Sussex in the United Kingdom and at Georgia Institute of Technology has been conducted developing algorithms of motor current signature analysis (CSA) and power signature analysis (PSA) resulting in a reliable model to predict motor and driven load failure. Pump cavitation, rotational unbalance and mechanical alignment are some of the areas where a mathematical model has been developed using Fast Fourier transform (FFT) analysis enabling online diagnostics during operation. An extensive testing program to validate and refine the mathematical model was conducted both in the test lab and in field process applications. A Motor Wellness Relay is under development in a mechanical package designed to replace a conventional thermal-overload relay of a NEMA or IEC rated motor starter. With this approach, the on-line Motor Wellness Relay enables CBM via a control device that is already required for the control circuit. This paper will discuss the mathematical model and field tests to validate the model and introduce a Motor Wellness Relay that could be used to perform on-line diagnostics. Alternative system communication architectures to support a wellness platform will also be reviewed and discussed

Analysis of Moving Target Defense Against False Data Injection Attacks on Power Grid

Recent studies have considered thwarting false data injection (FDI) attacks against state estimation in power grids by proactively perturbing branch susceptances. This approach is known as moving target defense (MTD). However, despite of the deployment of MTD, it is still possible for the attacker to launch stealthy FDI attacks generated with former branch susceptances. In this paper, we prove that, an MTD has the capability to thwart all FDI attacks constructed with former branch susceptances only if (i) the number of branches $l$ in the power system is not less than twice that of the system states $n$ (i.e., $l \geq 2n$, where $n + 1$ is the number of buses); (ii) the susceptances of more than $n$ branches, which cover all buses, are perturbed. Moreover, we prove that the state variable of a bus that is only connected by a single branch (no matter it is perturbed or not) can always be modified by the attacker. Nevertheless, in order to reduce the attack opportunities of potential attackers, we first exploit the impact of the susceptance perturbation magnitude on the dimension of the \emph{stealthy attack space}, in which the attack vector is constructed with former branch susceptances. Then, we propose that, by perturbing an appropriate set of branches, we can minimize the dimension of the \emph{stealthy attack space} and maximize the number of covered buses. Besides, we consider the increasing operation cost caused by the activation of MTD. Finally, we conduct extensive simulations to illustrate our findings with IEEE standard test power systems