Slow-scan operation of long linear CCD arrays

Linear CCD arrays used singly or in optically butted assemblies permit practical implementation of long line array systems with 6000 or more picture elements per line with readout rates in excess of 5 MHz. Display and tape recording of slow scan imagery with over 1000 picture elements per line also presents unique challenges. This paper discusses performance results and the operation of 1728-element CCD arrays for generation of high resolution slow scan imagery and some approaches for recording and display of the imagery. The implication of dark current and its control are discussed

Comparison of force and tactile feedback for grasp force control in telemanipulation

The comparative efficacy of using direct force feedback or a simple vibrotactile display to convey changes in the intensity of remote grasp force relayed from a robotic end effector is examined. The findings show that a simple vibrotactile cue, in the absence of direct force feedback, is effective in signaling abrupt changes in remote grasp force regardless of magnitude, and when changes in force are not too slow or protracted in nature (i.e., ramp time less than 2 s). In cases where the operator must dynamically tract and respond to slow but large variations in grasp force, the comparatively crude vibrotactile display would prove helpful; but would not be as effective as that of a direct contact force display. Immediate applications and utility of current generation and near-term prototype tactile displays are discussed

Display aids for remote control of untethered undersea vehicles

A predictor display superimposed on slow-scan video or sonar data is proposed as a method to allow better remote manual control of an untethered submersible. Simulation experiments show good control under circumstances which otherwise make control practically impossible

Walking to the beat of their own drum: how children and adults meet timing constraints

Walking requires adapting to meet task constraints. Between 5- and 7-years old, children's walking approximates adult walking without constraints. To examine how children and adults adapt to meet timing constraints, 57 5- to 7-year olds and 20 adults walked to slow and fast audio metronome paces. Both children and adults modified their walking. However, at the slow pace, children had more trouble matching the metronome compared to adults. The youngest children's walking patterns deviated most from the slow metronome pace, and practice improved their performance. Five-year olds were the only group that did not display carryover effects to the metronome paces. Findings are discussed in relation to what contributes to the development of adaptation in children

Accelerated Universes from type IIA Compactifications

We study slow-roll accelerating cosmologies arising from geometric compactifications of type IIA string theory on $T^{6}/(\mathbb{Z}_{2}\,\times\,\mathbb{Z}_{2})$. With the aid of a genetic algorithm, we are able to find quasi-de Sitter backgrounds with both slow-roll parameters of order $0.1$. Furthermore, we study their evolution by numerically solving the corresponding time-dependent equations of motion, and we show that they actually display a few e-folds of accelerated expansion. Finally, we comment on their perturbative reliability.Comment: 22 pages, 3 figures and 5 table

Quantum Quenches in Free Field Theory: Universal Scaling at Any Rate

Quantum quenches display universal scaling in several regimes. For quenches which start from a gapped phase and cross a critical point, with a rate slow compared to the initial gap, many systems obey Kibble-Zurek scaling. More recently, a different scaling behaviour has been shown to occur when the quench rate is fast compared to all other physical scales, but still slow compared to the UV cutoff. We investigate the passage from fast to slow quenches in scalar and fermionic free field theories with time dependent masses for which the dynamics can be solved exactly for all quench rates. We find that renormalized one point functions smoothly cross over between the regimes.Comment: 40 pages; v2: a bit late, but it includes minor modifications to match published versio

Microwave background constraints on inflationary parameters

We use a compilation of cosmic microwave anisotropy data (including the recent VSA, CBI and Archeops results), supplemented with an additional constraint on the expansion rate, to directly constrain the parameters of slow-roll inflation models. We find good agreement with other papers concerning the cosmological parameters, and display constraints on the power spectrum amplitude from inflation and the first two slow-roll parameters, finding in particular that $\epsilon_1 < 0.057$. The technique we use for parametrizing inflationary spectra may become essential once the data quality improves significantly.Comment: 6 pages LaTeX file with figures incorporated. Major revisions including incorporation of new datasets (CBI and Archeops). Slow-roll inflation module for use with the CAMB program can be found at http://astronomy.cpes.susx.ac.uk/~sleach/inflation

Logarithmic Relaxation in a Kinetically Constrained Model

We present Monte Carlo simulations in a modification of the north-or-east-or-front model recently investigated by Berthier and Garrahan [J. Phys. Chem. B 109, 3578 (2005)]. In this coarse-grained model for relaxation in supercooled liquids, the liquid structure is substituted by a three-dimensional array of cells. A spin variable is assigned to each cell, with values 0 or 1 denoting respectively unexcited and excited local states in a mobility field. Change in local mobility (spin flip) for a given cell is permitted according to kinetic constraints determined by the mobilities of neighboring cells. In this work we keep the same kinetic constraints of the original model, but we introduce two types of cells (denoted as "fast'' and "slow'') with very different rates for spin flip. As a consequence, fast and slow cells exhibit very different relaxation times for spin correlators. While slow cells exhibit standard relaxation, fast cells display anomalous relaxation, characterized by a concave-to-convex crossover in spin correlators by changing temperature or composition. At intermediate state points logarithmic relaxation is observed over three time decades. These results display striking analogies with dynamic correlators reported in recent simulations on a bead-spring model for polymer blends.Comment: Major changes. To be published in Journal of Chemical Physic

New electron microscope employs new video display technique

Video display system for a scanning electron microscope provides slow scanning rates, a self-generated color gradient technique, and allows leisurely viewing of several hours. It also enables the viewing of areas where selected energy regions contribute relatively few electrons, and the changing of specimen position and magnification without adjustments