University of Waterloo

About: University of Waterloo is a education organization based out in Waterloo, Ontario, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 36093 authors who have published 93906 publications receiving 2948139 citations. The organization is also known as: UW & uwaterloo.

An Interior-Point Method for Semidefinite Programming

Abstract: We propose a new interior-point-based method to minimize a linear function of a matrix variable subject to linear equality and inequality constraints over the set of positive semidefinite matrices....

CFHTLenS: the Canada-France-Hawaii Telescope Lensing Survey

Abstract: We present the Canada–France–Hawaii Telescope Lensing Survey (CFHTLenS) that accurately determines a weak gravitational lensing signal from the full 154 deg^2 of deep multicolour data obtained by the CFHT Legacy Survey. Weak gravitational lensing by large-scale structure is widely recognized as one of the most powerful but technically challenging probes of cosmology. We outline the CFHTLenS analysis pipeline, describing how and why every step of the chain from the raw pixel data to the lensing shear and photometric redshift measurement has been revised and improved compared to previous analyses of a subset of the same data. We present a novel method to identify data which contributes a non-negligible contamination to our sample and quantify the required level of calibration for the survey. Through a series of cosmology-insensitive tests we demonstrate the robustness of the resulting cosmic shear signal, presenting a science-ready shear and photometric redshift catalogue for future exploitation.

Smart community: an internet of things application

Abstract: In this article, we introduce an Internet of Things application, smart community, which refers to a paradigmatic class of cyber-physical systems with cooperating objects (i.e., networked smart homes). We then define the smart community architecture, and describe how to realize secure and robust networking among individual homes. We present two smart community applications, Neighborhood Watch and Pervasive Healthcare, with supporting techniques and associated challenges, and envision a few value-added smart community services.

Noise spectroscopy through dynamical decoupling with a superconducting flux qubit

Abstract: Quantum coherence in natural and artificial spin systems is fundamental to applications ranging from quantum information science to magnetic-resonance imaging and identification. Several multipulse control sequences targeting generalized noise models have been developed to extend coherence by dynamically decoupling a spin system from its noisy environment. In any particular implementation, however, the efficacy of these methods is sensitive to the specific frequency distribution of the noise, suggesting that these same pulse sequences could also be used to probe the noise spectrum directly. Here we demonstrate noise spectroscopy by means of dynamical decoupling using a superconducting qubit with energy-relaxation time T1 =12 μs. We first demonstrate that dynamical decoupling improves the coherence time T 2 in this system up to the T2 =2 T1 limit (pure dephasing times exceeding 100 μs), and then leverage its filtering properties to probe the environmental noise over a frequency (f) range 0.2-20 MHz, observing a 1/fα distribution with α < 1. The characterization of environmental noise has broad utility for spin-resonance applications, enabling the design of optimized coherent-control methods, promoting device and materials engineering, and generally improving coherence. © 2011 Macmillan Publishers Limited. All rights reserved.

Review of load-flow calculation methods

Abstract: A survey is presented on the currently available numerical techniques for power-system load-flow calculation using the digital computer. The review deals with methods that have received widespread practical application, recent attractive developments, and other methods that have interesting or useful characteristics. The analytical bases, computational requirements, and comparative numerical performances of the methods are discussed. Attention is given to the problems and techniques of adjustments in load-flow solutions, and the suitabilities of various methods for modern applications such as security monitoring and optimal load flow are examined.