Performance Evaluation of FMOSSIM, a Concurrent Switch-Level Fault Simulator

This paper presents measurements obtained while performing fault simulations of MOS circuits modeled at the switch level. In this model the transistor structure of the circuit is represented explicitly as a network of charge storage nodes connected by bidirectional transistor switches. Since the logic model of the simulator closely matches the actual structure of MOS circuits, such faults as stuck-open and closed transistors as well as short and open-circuited wires can be simulated. By using concurrent simulation techniques, we obtain a performance level comparable to fault simulators using logic gate models. Our measurements indicate that fault simulation times grow as the product of the circuit size and number of patterns, assuming the number of faults to be simulated is proportional to the circuit size. However, fault simulation times depend strongly on the rate at which the test patterns detect the faults

Concurrent fault simulation of MOS digital circuits

The concurrent fault simulation technique is widely used to analyse the behavior of digital circuits in the presence of faults. We show how this technique can be applied to metal-oxide-semiconductor (MOS) digital circuits when modeled at the switch-level as a set of charge storage nodes connected by bidirectional transistor switches. The algorithm we present is capable of analysing the behavior of a wide variety of MOS circuit failures, such as stuck-at-zero or stuck-at-one nodes, stuck-open or stuck-closed transistors, or resistive opens or shorts. We have implemented a fault simulator FMOSSIM based on this algorithm. The capabilities and the peformance of this program demonstrate the advantages of combining switch-level and concurrent simulation techniques

Separation of suspended particles in microfluidic systems by directional-locking in periodic fields

We investigate the transport and separation of overdamped particles under the action of a uniform external force in a two-dimensional periodic energy landscape. Exact results are obtained for the deterministic transport in a square lattice of parabolic, repulsive centers that correspond to a piecewise-continuous linear-force model. The trajectories are periodic and commensurate with the obstacle lattice and exhibit phase-locking behavior in that the particle moves at the same average migration angle for a range of orientation of the external force. The migration angle as a function of the orientation of the external force has a Devil's staircase structure. The first transition in the migration angle was analyzed in terms of a Poincare map, showing that it corresponds to a tangent bifurcation. Numerical results show that the limiting behavior for impenetrable obstacles is equivalent to the high Peclet number limit in the case of transport of particles in a periodic pattern of solid obstacles. Finally, we show how separation occurs in these systems depending on the properties of the particles

Sub-system mechanical design for an eLISA optical bench

We present the design and development status of the opto-mechanical sub-systems that will be used in an experimental demonstration of imaging systems for eLISA. An optical bench test bed design incorporates a Zerodur® baseplate with lenses, photodetectors, and other opto-mechanics that must be both adjustable - with an accuracy of a few micrometers - and stable over a 0 to 40°C temperature range. The alignment of a multi-lens imaging system and the characterisation of the system in multiple degrees of freedom is particularly challenging. We describe the mechanical design of the precision mechanisms, including thermally stable flexure-based optical mounts and complex multi-lens, multi-axis adjuster mechanisms, and update on the integration of the mechanisms on the optical bench

Performance Evaluation of FMOSSIM, a Concurrent Switch-Level Fault Simulator

This paper presents measurements obtained while performing fault simulations of MOS circuits modeled at the switch level. In this model the transistor structure of the circuit is represented explicitly as a network of charge storage nodes connected by bidirectional transistor switches. Since the logic model of the simulator closely matches the actual structure of MOS circuits, such faults as stuck-open and closed transistors as well as short and open-circuited wires can be simulated. By using concurrent simulation techniques, we obtain a performance level comparable to fault simulators using logic gate models. Our measurements indicate that fault simulation times grow as the product of the circuit size and number of patterns, assuming the number of faults to be simulated is proportional to the circuit size. However, fault simulation times depend strongly on the rate at which the test patterns detect the faults

Potential converter for laser-power beaming

Future space missions, such as those associated with the Space Exploration Initiative (SEI), will require large amounts of power for operation of bases, rovers, and orbit transfer vehicles. One method for supplying this power is to beam power from a spaced based or Earth based laser power station to a receiver where laser photons can be converted to electricity. Previous research has described such laser power stations orbiting the Moon and beaming power to a receiver on the surface of the Moon by using arrays of diode lasers. Photovoltaic converters that can be efficiently used with these diode lasers are described

Method for remotely powering a device such as a lunar rover

A method of supplying power to a device such as a lunar rover located on a planetary surface is provided. At least one, and preferably three, laser satellites are set in orbit around the planet. Each satellite contains a nuclear reactor for generating electrical power. This electrical power is converted into a laser beam which is passed through an amplifying array and directed toward the device such as a lunar rover. The received laser beam is then converted into electrical power for use by the device

Phase-Coherent Transport through a Mesoscopic System: A New Probe of Non-Fermi-Liquid Behavior

A novel chiral interferometer is proposed that allows for a direct measurement of the phase of the transmission coefficient for transport through a variety of mesoscopic structures in a strong magnetic field. The effects of electron-electron interaction on this phase is investigated with the use of finite-size bosonization techniques combined with perturbation theory resummation. New non-Fermi-liquid phenomena are predicted in the FQHE regime that may be used to distinguish experimentally between Luttinger and Fermi liquids.Comment: 4 pages, 3 figures, Revte

Down-regulation of Plasminogen Activator Inhibitor 1 Expression Promotes Myocardial Neovascularization by Bone Marrow Progenitors

Human adult bone marrow–derived endothelial progenitors, or angioblasts, induce neovascularization of infarcted myocardium via mechanisms involving both cell surface urokinase-type plasminogen activator, and interactions between β integrins and tissue vitronectin. Because each of these processes is regulated by plasminogen activator inhibitor (PAI)-1, we selectively down-regulated PAI-1 mRNA in the adult heart to examine the effects on postinfarct neovascularization and myocardial function. Sequence-specific catalytic DNA enzymes inhibited rat PAI-1 mRNA and protein expression in peri-infarct endothelium within 48 h of administration, and maintained down-regulation for at least 2 wk. PAI-1 inhibition enhanced vitronectin-dependent transendothelial migration of human bone marrow–derived CD34+ cells, and resulted in a striking augmentation of angioblast-dependent neovascularization. Development of large, thin-walled vessels at the peri-infarct region was accompanied by induction of proliferation and regeneration of endogenous cardiomyocytes and functional cardiac recovery. These results identify a causal relationship between elevated PAI-1 levels and poor outcome in patients with myocardial infarction through mechanisms that directly inhibit bone marrow–dependent neovascularization. Strategies that reduce myocardial PAI-1 expression appear capable of enhancing cardiac neovascularization, regeneration, and functional recovery after ischemic insult

Charged particle (pseudo-)rapidity distributions in proton+anti-proton/proton+proton and Pb+Pb/Au+Au collisions from SPS to LHC energies from UrQMD

We present results for final state charged particle (pseudo-)rapidity distributions in $\rm{p}$ + $\bar{\rm{p}}$ / $\rm{p}$ + $\rm{p}$ and Pb+Pb/Au+Au at ultra high energies (17.3 GeV $\leq$ $\sqrt{s_{\rm{NN}}}$ $\leq$ 14 TeV) from the Ultra-relativistic Quantum Molecular Dynamics (UrQMD-v2.3) model. In addition, excitation functions of produced charged particle multiplicities ($N_{\rm{ch}}$) and pseudorapidity spectra are investigated up to LHC energies. Good agreement is observed between UrQMD and measured pseudorapidity distributions of charged particles up to the highest Tevatron and Sp$\bar{\rm{p}}$S energies.Comment: 6 pages, 7 figure