Security Issues in a SOA-based Provenance System

Recent work has begun exploring the characterization and utilization of provenance in systems based on the Service Oriented Architecture (such as Web Services and Grid based environments). One of the salient issues related to provenance use within any given system is its security. Provenance presents some unique security requirements of its own, which are additionally dependent on the architectural and environmental context that a provenance system operates in. We discuss the security considerations pertaining to a Service Oriented Architecture based provenance system. Concurrently, we outline possible approaches to address them

Global Linear Complexity Analysis of Filter Keystream Generators

An efficient algorithm for computing lower bounds on the global linear complexity of nonlinearly filtered PN-sequences is presented. The technique here developed is based exclusively on the realization of bit wise logic operations, which makes it appropriate for both software simulation and hardware implementation. The present algorithm can be applied to any arbitrary nonlinear function with a unique term of maximum order. Thus, the extent of its application for different types of filter generators is quite broad. Furthermore, emphasis is on the large lower bounds obtained that confirm the exponential growth of the global linear complexity for the class of nonlinearly filtered sequences

The self-consistent quantum-electrostatic problem in strongly non-linear regime

The self-consistent quantum-electrostatic (also known as Poisson-Schr\"odinger) problem is notoriously difficult in situations where the density of states varies rapidly with energy. At low temperatures, these fluctuations make the problem highly non-linear which renders iterative schemes deeply unstable. We present a stable algorithm that provides a solution to this problem with controlled accuracy. The technique is intrinsically convergent including in highly non-linear regimes. We illustrate our approach with (i) a calculation of the compressible and incompressible stripes in the integer quantum Hall regime and (ii) a calculation of the differential conductance of a quantum point contact geometry. Our technique provides a viable route for the predictive modeling of the transport properties of quantum nanoelectronics devices.Comment: 28 pages. 14 figures. Added solution to a potential failure mode of the algorith

Towards Reconstructing the Provenance of Clinical Guidelines

Abstract. Understanding the provenance of clinical guidelines is important for both practitioners and researchers as it allows for deeper understanding of the provided recommendations and could potentially provide a basis for updating guidelines. Often such provenance is incomplete or unavailable. We describe a prototype of a multi-signal pipeline for reconstructing provenance and show preliminary results of reconstructing dependencies between documents in the context of clinical guidelines and associated documents. 1 Prototype description Broadly, we target the problem of reconstructing provenance of files in a shared folder setting, in which several authors can create or edit files at different moments, and only standard filesystem metadata is available. In a previous work [3] we proposed a content-based approach that is able to reconstruct provenance automatically, leveraging several similarity measures and edit distance algorithms, which are then adapted and integrated them into a multi-signal pipeline. Here, we present an improved version of this prototype applied to a clinical guideline and associated biomedical documents. The architecture of our prototype is shown in Fig. 1. <2,4

Sensing electric and magnetic fields with Bose-Einstein Condensates

We discuss the application of Bose-Einstein condensates (BECs) as sensors for magnetic and electric fields. In an experimental demonstration we have brought one-dimensional BECs close to micro-fabricated wires on an atom chip and thereby reached a sensitivity to potential variations of ~10e-14eV at 3 micron spatial resolution. We demonstrate the versatility of this sensor by measuring a two-dimensional magnetic field map 10 micron above a 100-micron-wide wire. We show how the transverse current-density component inside the wire can be reconstructed from such maps. The field sensitivity in dependence on the spatial resolution is discussed and further improvements utilizing Feshbach resonances are outlined.Comment: 4 pages, 3 figure