Atomic Beam Research

Contains reports on one research project

Atomic Beam Research

Contains research objectives and reports on five research projects

Generalized Gravi-Electromagnetism

A self consistant and manifestly covariant theory for the dynamics of four charges (masses) (namely electric, magnetic, gravitational, Heavisidian) has been developed in simple, compact and consistent manner. Starting with an invariant Lagrangian density and its quaternionic representation, we have obtained the consistent field equation for the dynamics of four charges. It has been shown that the present reformulation reproduces the dynamics of individual charges (masses) in the absence of other charge (masses) as well as the generalized theory of dyons (gravito - dyons) in the absence gravito - dyons (dyons). key words: dyons, gravito - dyons, quaternion PACS NO: 14.80H

Atomic Beam Research

Contains reports on one research project

Atomic Beam Research

Contains reports on three research projects

Accelerating reconfiguration of network anomaly detection systems

Reducing the time required to keep an anomaly-based network intrusion detection system (NIDS) up-to-date with the continuously changing web server features is of the utmost importance to keep intrusion detection as accurate as possible. Web applications and content changes frequently on web servers to keep their users interested and returning. This frequent updating poses an interesting problem with regards to anomaly-based network intrusion detection systems (NIDS) as they rely on knowing what normal traffic patterns look like. Retraining and reconfiguration to adapt to new applications or features of a website is highly advised to maintain accurate detection performance. Training an anomaly-based NIDS can be a major strain on computational resources and a time sink. Through the use of cost efficient, off-the-shelf hardware, the training of an anomaly-based NIDS may be offloaded from a web server\u27s central processing unit (CPU) onto a single instruction, multiple data (SIMD) architecture device and completed hundreds of time faster. Some anomaly-based NIDS algorithms lend themselves to other approaches like a genetic algorithm for accelerated training. An automated search through the input parameter solution space may completed in an efficient manner to reduce the time required for choosing the appropriate input parameters. In this thesis, the use of graphics processing units (GPU) and a genetic algorithm search heuristic are studied to accelerate the reconfiguration time of two different anomaly and payload-based NIDS. A demonstration of a SIMD implementation is shown on the Payload-based Dispersion (PBD) algorithm, highlighting the data parallel computational design and how to distribute workloads to be processed by individual threads. The SIMD implementation of the PBD algorithm achieves comparable results to other related works, speeding up certain portions of the algorithm from approximately 28 to 55 times. The Lightweight Stateless Payload Inspection (LiSPI) algorithm is selected to show a different use of data parallel computation and a genetic algorithm to achieve fast reconfiguration times. The LiSPI algorithm requires appropriate input parameters to achieve accurate detection performance. The default parameters required to run the algorithm results in a solution space of approximately 43 million combinations, which may grow depending on the parameters provided. A brute force search using the GPU yields optimal results in minutes, where as a serial implementation would require weeks of computation. The genetic algorithm approach also results in acceleration performance similar to the GPU brute force

Caenorhabditis elegans dnj-14, the orthologue of the DNAJC5 gene mutated in adult onset neuronal ceroid lipofuscinosis, provides a new platform for neuroprotective drug screening and identifies a SIR-2.1-independent action of resveratrol

Adult onset neuronal lipofuscinosis (ANCL) is a human neurodegenerative disorder characterized by progressive neuronal dysfunction and premature death. Recently, the mutations that cause ANCL were mapped to the DNAJC5 gene, which encodes cysteine string protein alpha. We show here that mutating dnj-14, the Caenorhabditis elegans orthologue of DNAJC5, results in shortened lifespan and a small impairment of locomotion and neurotransmission. Mutant dnj-14 worms also exhibited age-dependent neurodegeneration of sensory neurons, which was preceded by severe progressive chemosensory defects. A focussed chemical screen revealed that resveratrol could ameliorate dnj-14 mutant phenotypes, an effect mimicked by the cAMP phosphodiesterase inhibitor, rolipram. In contrast to other worm neurodegeneration models, activation of the Sirtuin, SIR-2.1, was not required, as sir-2.1; dnj-14 double mutants showed full lifespan rescue by resveratrol. The Sirtuin-independent neuroprotective action of resveratrol revealed here suggests potential therapeutic applications for ANCL and possibly other human neurodegenerative diseases

Toroidal quadrupole transitions associated to collective rotational-vibrational motions of the nucleus

In the frame of the algebraic Riemann Rotational Model one computes the longitudinal, transverse and toroidal multipoles corresponding to the excitations of low-lying levels in the ground state band of several even-even nuclei by inelastic electron scattering (e,e'). Related to these transitions a new quantity, which accounts for the deviations from the Siegert theorem, is introduced. The intimate connection between the nuclear vorticity and the dynamic toroidal quadrupole moment is underlined. Inelastic differential cross-sections calculated at backscattering angles shows the dominancy of toroidal form-factors over a broad range of momentum transfer.Comment: 11 pages in LaTex, 3 figures available by fax or mail, accepted for publication in J.Phys.

Meridional Circulation and Global Solar Oscillations

We investigate the influence of large-scale meridional circulation on solar p-modes by quasi-degenerate perturbation theory, as proposed by \cite{lavely92}. As an input flow we use various models of stationary meridional circulation obeying the continuity equation. This flow perturbs the eigenmodes of an equilibrium model of the Sun. We derive the signatures of the meridional circulation in the frequency multiplets of solar p-modes. In most cases the meridional circulation leads to negative average frequency shifts of the multiplets. Further possible observable effects are briefly discussed.Comment: 14 pages, 5 figures, submittted to Solar Physics Topical Issue "HELAS

Alternative Fourier Expansions for Inverse Square Law Forces

Few-body problems involving Coulomb or gravitational interactions between pairs of particles, whether in classical or quantum physics, are generally handled through a standard multipole expansion of the two-body potentials. We discuss an alternative based on a compact, cylindrical Green's function expansion that should have wide applicability throughout physics. Two-electron "direct" and "exchange" integrals in many-electron quantum systems are evaluated to illustrate the procedure which is more compact than the standard one using Wigner coefficients and Slater integrals.Comment: 10 pages, latex/Revtex4, 1 figure