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