15,626 research outputs found
A Novel Optical Package for ATLAS Pixel Detector
An optical package of novel design has been developed for the ATLAS pixel
detector. The package contains two VCSELs and one PIN diode to transmit and
receive optical signals. The design is based on a simple connector-type concept
and is made of radiation-hard material. Several packages have been fabricated
and show promising results.Comment: 3 pages, 1 figure, to be published in Proc. of the 2000 Annual
Meeting of the Division of Particles and Fields of the American Physical
Society, Columbus, Ohi
New Results on ATLAS Pixel Opto-Link
We present new results on the optical link for the pixel detector of the
ATLAS experiment. An optical package of novel design has been developed for the
opto-link. The design is based on a simple connector-type concept and is made
of radiation-hard material. The receiver (DORIC) and transmitter (VDC) chips
have been designed. The prototype results using the 0.8 and 0.25 um
technologies are presented.Comment: International Europhysics Conference on High Energy Physics,
Budapest, 200
New CLEO II Results on Charm Hadron Decays
We present new results on charm hadron decays from the CLEO II experiment.
The D*+ width is measured for the first time, Gamma(D*+) = 96 +- 4 +- 22 keV.
The semileptonic decay branching fractions are determined to be B(D+ --> Kbar*0
e+ nu_e) = (6.7 +- 0.4 +- 0.5 +- 0.4)% and B(D+ --> Kbar*0 mu+ nu_mu) = (6.5 +-
0.9 +- 0.5 +- 0.4)%. We observe evidence for Omega_c --> Omega- e+ nu_e and
measure the product of the branching fraction and cross section, B(Omega_c -->
Omega- e+ nu_e) x sigma(e+e- --> Omega_cX) = 42.2 +- 14.1 +- 11.9 fb. Within
the framework of Heavy Quark Effective Theory, we measure in the decay
Lambda+_c --> Lambda e+ nu_e the form factor ratio, R = f_2/f_1 = -0.31 +- 0.06
+- 0.06. This provides strong evidence that the form factor f_2 describing spin
interactionof the s quark is non-zero. The Xi+_c lifetime is measured to be 503
+- 47 +- 18 fs. The results on branching fractions, cross section, and form
factor ratio are preliminary.Comment: International Europhysics Conference on HEP, Budapest, 200
Convolutional compressed sensing using deterministic sequences
This is the author's accepted manuscript (with working title "Semi-universal convolutional compressed sensing using (nearly) perfect sequences"). The final published article is available from the link below. Copyright @ 2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works.In this paper, a new class of orthogonal circulant matrices built from deterministic sequences is proposed for convolution-based compressed sensing (CS). In contrast to random convolution, the coefficients of the underlying filter are given by the discrete Fourier transform of a deterministic sequence with good autocorrelation. Both uniform recovery and non-uniform recovery of sparse signals are investigated, based on the coherence parameter of the proposed sensing matrices. Many examples of the sequences are investigated, particularly the Frank-Zadoff-Chu (FZC) sequence, the m-sequence and the Golay sequence. A salient feature of the proposed sensing matrices is that they can not only handle sparse signals in the time domain, but also those in the frequency and/or or discrete-cosine transform (DCT) domain
Beamforming Optimization for Full-Duplex Wireless-powered MIMO Systems
We propose techniques for optimizing transmit beamforming in a full-duplex
multiple-input-multiple-output (MIMO) wireless-powered communication system,
which consists of two phases. In the first phase, the wireless-powered mobile
station (MS) harvests energy using signals from the base station (BS), whereas
in the second phase, both MS and BS communicate to each other in a full-duplex
mode. When complete instantaneous channel state information (CSI) is available,
the BS beamformer and the time-splitting (TS) parameter of energy harvesting
are jointly optimized in order to obtain the BS-MS rate region. The joint
optimization problem is non-convex, however, a computationally efficient
optimum technique, based upon semidefinite relaxation and line-search, is
proposed to solve the problem. A sub-optimum zero-forcing approach is also
proposed, in which a closed-form solution of TS parameter is obtained. When
only second-order statistics of transmit CSI is available, we propose to
maximize the ergodic information rate at the MS, while maintaining the outage
probability at the BS below a certain threshold. An upper bound for the outage
probability is also derived and an approximate convex optimization framework is
proposed for efficiently solving the underlying non-convex problem. Simulations
demonstrate the advantages of the proposed methods over the sub-optimum and
half-duplex ones.Comment: 14 pages, accepte
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