Abstract – Many real-world networks exhibit a high degeneracy at few eigenvalues. We show that a simple transformation of the network’s adjacency matrix provides an understanding to the origins of occurrence of high multiplicities in the networks spectra. We find that the eigenvectors associated with the degenerate eigenvalues shed light on the structures contributing to the degeneracy. Since t...

The introduction of Exascale storage into production systems will lead to an increase on the number of storage servers needed by parallel file systems. In this scenario, parallel file system designers should move from the current replication configurations to the more space and energy efficient erasure-coded configurations between storage servers. Unfortunately, the current trends on energy eff...

Controlled Perturbation is a framework for perturbing geometric arrangements to make them more robust for further manipulation. The idea is to slightly perturb the arrangement to make it more robust for finite precision arithmetic. We present a Controlled Perturbation scheme for arrangements of line segments in IR (CPAL for short). CPAL perturbs the endpoints of the arrangement to eliminate deg...

For hydrologic applications, terrain models should have few local minima, and drainage lines should coincide with edges. We show that triangulating a set of points with elevations such that the number of local minima of the resulting terrain is minimized is NP-hard for degenerate point sets. The same result applies when there are no degeneracies for higher-order Delaunay triangulations. Two heu...

Life cycle assessment framework for railway bridges: literature survey and critical issues Guangli Du & Raid Karoumi To cite this article: Guangli Du & Raid Karoumi (2014) Life cycle assessment framework for railway bridges: literature survey and critical issues, Structure and Infrastructure Engineering, 10:3, 277-294, DOI: 10.1080/15732479.2012.749289 To link to this article: http://dx.doi.org...

This paper shows that the mass-sheet degeneracy and other degeneracies in lensing have simple geometrical interpretations: they are mostly rescalings of the arrival-time surface. Different degeneracies appear in Local Group lensing and in cosmological lensing, because in the former the absolute magnification is measured but the image structure is not resolved, whereas in the latter the reverse ...

The accelerating expansion of the universe suggests that an unknown component with strongly negative pressure, called dark energy, currently dominates the dynamics of the universe. Such a component makes up ;70% of the energy density of the universe yet has not been predicted by the standard model of particle physics. The best method for exploring the nature of this dark energy is to map the re...

The Olivetti Research Laboratory has developed an experimental system based on intelligent peripherals connected directly to an ATM network. As well as multimedia modules (e.g. audio and video) the system also includes a directly connected RAID-3 storage server called the “Disc Brick”. This paper describes the architecture of the Disc Brick, and discusses some of the hardware and software issue...

In this paper, we propose SiLo, a novel energy efficient shifted logging storage architecture, for write-oriented workloads. By organizing free storage space of redundant mirrored disks in a RAID10 system into a logical logging space pool and shifting logger among different mirrored disk pairs, only one or few mirrored disk pairs are used as the on-duty logger at a time and all the other off-du...

In a classical Symbolic Perturbation scheme, degeneracies are handled by substituting some polynomials in ε for the inputs of a predicate. Instead of a single perturbation, we propose to use a sequence of (simpler) perturbations. Moreover, we look at their effects geometrically instead of algebraically; this allows us to tackle cases that were not tractable with the classical algebraic approach...