École Polytechnique Fédérale de Lausanne
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Practical Sketching Algorithms For Low-Rank Matrix Approximation
No full textThis paper describes a suite of algorithms for constructing low-rank approximations of an input matrix from a random linear image, or sketch, of the matrix. These methods can preserve structural properties of the input matrix, such as positive-semidefiniteness, and they can produce approximations with a user-specified rank. The algorithms are simple, accurate, numerically stable, and provably correct. Moreover, each method is accompanied by an informative error bound that allows users to select parameters a priori to achieve a given approximation quality. These claims are supported by numerical experiments with real and synthetic data.LION
Imaging and pattern projection through multicore fibers using the memory effect
No full textIt is possible to focus coherent light through a multicore fiber with a resolution finer than the core-to-core spacing using digital phase conjugation. In this paper we use the memory effect and show that the displacement of the focus spot can be realized simply by tilting the beam incident on the multicore fiber. We demonstrate high-resolution imaging and pattern projection with a calibration procedure consisting of the acquisition of a single digital hologram.LOLAP
Detection of proteins on membranes and in microchannels using copper staining combined with Scanning Electrochemical Microscopy
Get PDFScanning Electrochemical Microscopy (SECM) and copper staining are combined to achieve visualisation of proteins on surfaces. Proteins are adsorbed on a polyvinylidene fluoride (PVDF) membrane or on a polyethylene terephthalate (PET) surface and stained using a standard protocol involving copper salts. Salts are then reduced to copper and detected by SECM with ferrocene methanol as a redox mediator in aqueous solution. During the SECM scan, the potential is held at a value at which the oxidation of the redox mediator occurs and a positive feedback current is detected when scanning over copper clusters. A negative feedback is observed elsewhere. This method enables unspecific protein adsorption mapping on polymeric membranes and into microchannels without any requirement of enzymatic activity or affinity to a labelled secondary reporter.LEP
A Distributed Architecture for Teleoperation over the Internet with Application to the Remote Control of an Inverted Pendulum
No full textThis paper discusses challenges in enabling teleoperation over the Internet for the specific case of real systems which exhibit fast dynamics. A distributed client-server architecture is proposed to provide the necessary level of interactivity for supervision and tuning, without compromising the essential control tasks. Enabling features include real-time simulation and augmented-reality visualization to enhance the user perception of the distant ongoing operations. The proposed approach is illustrated through the remote control of an inverted pendulum.LASCI-STI-D
Acoustic tomography for estimating temperature and wind flow
Get PDFWe consider the problem of reconstructing superimposed temperature and wind flow fields from acoustic measurements. A new technique based solely on acoustic wave propagation is presented. In contrast to the usual straight ray assumption, a bent ray model is considered in order to achieve higher accuracy. We also develop a lab size experiment for temperature estimation.LCA
