152,098 research outputs found
Instantaneous ionization rate as a functional derivative
We describe an approach defining instantaneous ionization rate (IIR) as a
functional derivative of the total ionization probability. The definition is
based on physical quantities which are directly measurable, such as the total
ionization probability and the waveform of the pulse. The definition is,
therefore, unambiguous and does not suffer from gauge non-invariance. We
compute IIR by solving numerically the time-dependent Schrodinger equation for
the hydrogen atom in a strong laser field. We find that the IIR lags behind the
electric field, but this lag is entirely due to the long tail effect of the
Coulomb field. In agreement with the previous results using attoclock
methodology, therefore, the IIR we define does not show measurable delay in
strong field tunnel ionization
Timely Updates over an Erasure Channel
Using an age of information (AoI) metric, we examine the transmission of
coded updates through a binary erasure channel to a monitor/receiver. We start
by deriving the average status update age of an infinite incremental redundancy
(IIR) system in which the transmission of a k-symbol update continuesuntil k
symbols are received. This system is then compared to a fixed redundancy (FR)
system in which each update is transmitted as an n symbol packet and the packet
is successfully received if and only if at least k symbols are received. If
fewer than k symbols are received, the update is discarded. Unlike the IIR
system, the FR system requires no feedback from the receiver. For a single
monitor system, we show that tuning the redundancy to the symbol erasure rate
enables the FR system to perform as well as the IIR system. As the number of
monitors is increased, the FR system outperforms the IIR system that guarantees
delivery of all updates to all monitors
CAFS: A Cesium Atomic Frequency Standard for GPS block IIR
Kernco, Inc. was selected to design the Cesium Atomic Frequency Standards (CAFS) for the GPS Block IIR NAVSTAR satellites. These spacecraft are scheduled to be launched in the mid-1990's to replenish and upgrade the existing constellation of Global Positioning System satellites. The Block IIR CAFS output frequency is 13.4003378 MHz, the 686th submultiple of the cesium atomic resonance frequency. Using an integer submultiple simplifies the design of the atomic frequency standard's rf multiplier circuits, eliminating the secondary frequency synthesizer needed in previous designs. The GPS Block IIR CAFS design, particularly the improvements made on our earlier Block II design is described. Test results are included
Implementation of a Two-Channel Maximally Decimated Filter Bank using Switched Capacitor Circuits
The aim of this paper is to describe the implementation of a two-channel filter bank (FB) using the switched capacitor (SC) technique considering real properties of operational amplifiers (OpAmps). The design procedure is presented and key recommendations for the implementation are given. The implementation procedure describes the design of two-channel filter bank using an IIR Cauer filter, conversion of IIR into the SC filters and the final implementation of the SC filters. The whole design and an SC circuit implementation is performed by a PraCAn package in Maple. To verify the whole filter bank, resulting real property circuit structures are completely simulated by WinSpice and ELDO simulators. The results confirm that perfect reconstruction conditions can be almost accepted for the filter bank implemented by the SC circuits. The phase response of the SC filter bank is not strictly linear due to the IIR filters. However, the final ripple of a magnitude frequency response in the passband is almost constant, app. 0.5 dB for a real circuit analysis
NEGARA SEKULAR–ISLAM Deskripsi Pandangan Dr. Muhammad Syahrur Mengenai Hubungan Syura, Demokrasi dan Negara dalam Islam
Al-Qur`an as main source of thought in Islam, viewed, has the fundamental norm-ethic and principles of society and individual life needed in the modern democratic state. The State as peak institutional model of human comunity interaction is accumulation of knowledge conscience, ethic value, social and politic behaviour that held in society life as the subjective and objective dimension of state. That can be realizied if civil rights garanted and protected totally as same as everyone can build the human material-spiritual capasities in the diversity paths. Argued, Islam which based to syariah and nubuwwah dimension -- that recited and actuated in contemporary model of syura as high value of islamic democratic and humanity – propose a secular state system based to Islamic fundamental norm
Establishing an Online Access Panel for Interactive Information Retrieval Research
We propose an online access panel to support the evaluation process of
Interactive Information Retrieval (IIR) systems - called IIRpanel. By
maintaining an online access panel with users of IIR systems we assume that the
recurring effort to recruit participants for web-based as well as for lab
studies can be minimized. We target on using the online access panel not only
for our own development processes but to open it for other interested
researchers in the field of IIR. In this paper we present the concept of
IIRpanel as well as first implementation details.Comment: 2 pages, 1 figure, 2014 IEEE/ACM Joint Conference on Digital
Libraries (JCDL), London, 8th-12th September 201
On the eigenfilter design method and its applications: a tutorial
The eigenfilter method for digital filter design involves the computation of filter coefficients as the eigenvector of an appropriate Hermitian matrix. Because of its low complexity as compared to other methods as well as its ability to incorporate various time and frequency-domain constraints easily, the eigenfilter method has been found to be very useful. In this paper, we present a review of the eigenfilter design method for a wide variety of filters, including linear-phase finite impulse response (FIR) filters, nonlinear-phase FIR filters, all-pass infinite impulse response (IIR) filters, arbitrary response IIR filters, and multidimensional filters. Also, we focus on applications of the eigenfilter method in multistage filter design, spectral/spacial beamforming, and in the design of channel-shortening equalizers for communications applications
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