Methods for verifying the accuracy of wind profiles

Comparisons of radar-measured winds have been made with several types of measurements not only to verify radar data but also to seek a satisfactory comparison method. Three of the comparisons that have been made with Colorado Profiler radars are summarized. Radar measurements were compared with radiosonde measurements. Infrared lidar and 915 MHz radar were compared with radiosondes. A brief radar/radar comparison was made using the 50-MHz radar and a 3-cm wavelength meteorological Doppler radar during precipitation

Fast PCA for processing calcium-imaging data from the brain of Drosophila melanogaster

<p>Abstract</p> <p>Background</p> <p>The calcium-imaging technique allows us to record movies of brain activity in the antennal lobe of the fruitfly <it>Drosophila melanogaster</it>, a brain compartment dedicated to information about odors. Signal processing, e.g. with source separation techniques, can be slow on the large movie datasets.</p> <p>Method</p> <p>We have developed an approximate Principal Component Analysis (PCA) for fast dimensionality reduction. The method samples relevant pixels from the movies, such that PCA can be performed on a smaller matrix. Utilising <it>a priori </it>knowledge about the nature of the data, we minimise the risk of missing important pixels.</p> <p>Results</p> <p>Our method allows for fast approximate computation of PCA with adaptive resolution and running time. Utilising <it>a priori </it>knowledge about the data enables us to concentrate more biological signals in a small pixel sample than a general sampling method based on vector norms.</p> <p>Conclusions</p> <p>Fast dimensionality reduction with approximate PCA removes a computational bottleneck and leads to running time improvements for subsequent algorithms. Once in PCA space, we can efficiently perform source separation, e.g to detect biological signals in the movies or to remove artifacts.</p

Ultra-Efficient Cooling of Resonators: Beating Sideband Cooling with Quantum Control

The present state-of-the-art in cooling mechanical resonators is a version of "sideband" cooling. Here we present a method that uses the same configuration as sideband cooling --- coupling the resonator to be cooled to a second microwave (or optical) auxiliary resonator --- but will cool significantly colder. This is achieved by varying the strength of the coupling between the two resonators over a time on the order of the period of the mechanical resonator. As part of our analysis, we also obtain a method for fast, high-fidelity quantum information-transfer between resonators.Comment: 4 pages, revtex4-1, 2 png figure

A procedure model for evaluating IT-security investments

The security of information systems is a vital factor for companies nowadays. In order to achieve an adequate level of security, a variety of distinct measures is available, ranging from technical meas-ures to organizational measures. In near past suitable methods for decision support especially for the assessment of the profitability of IT-security investments have been developed. But integrated procedure models for a complete it-security controlling can neither be found in literature nor in practice. With this article, we propose a method framework that enables the analysis of the results of alternative security investments from a process-oriented perspective. As a basis, we have conducted an in-deep analysis of the state-of-the-art in the fields of IT-Business-Alignment and IT-security management in order to identify suitable concepts for the framework. A special focus lies on the requirements of IT-security controlling of critical business processes.Безпека інформаційних систем у теперішній час є життєво важливим фактором для компаній. Багато різних вимірів, від технічних до організаційних, є доступними для досягнення прийнятного рівня безпеки. У недалекому минулому було розроблено методи підтримки прийняття рішень при оцінюванні прибутковості інвестицій у IT-безпеку. Проте інтегральні процедурні моделі для повного управління IT-безпекою до цього часу не знайдені – ані у літературі, ані на практиці. У цієї статті ми пропонуємо середовище, яке дає можливість аналізувати результати альтернативних інвестицій у безпеку з точки зору, орієнтованої на процеси. Ми здійснили поглиблений аналіз сучасного стану справ у галузях синхронізації IT та бізнесу та управління IT-безпекою з метою ідентифікувати прийнятні концепції для цього середовища. Спеціальну увагу приділено вимогам до IT-безпеки критичних бізнес-процесів

Any-order propagation of the nonlinear Schroedinger equation

We derive an exact propagation scheme for nonlinear Schroedinger equations. This scheme is entirely analogous to the propagation of linear Schroedinger equations. We accomplish this by defining a special operator whose algebraic properties ensure the correct propagation. As applications, we provide a simple proof of a recent conjecture regarding higher-order integrators for the Gross-Pitaevskii equation, extend it to multi-component equations, and to a new class of integrators.Comment: 10 pages, no figures, submitted to Phys. Rev.

Estimated Flood Discharges and Map of Flood-Inundated Areas for Omaha Creek, near Homer, Nebraska, 2005

Repeated flooding of Omaha Creek has caused damage in the Village of Homer. Long-term degradation and bridge scouring have changed substantially the channel characteristics of Omaha Creek. Flood-plain managers, planners, homeowners, and others rely on maps to identify areas at risk of being inundated. To identify areas at risk for inundation by a flood having a 1-percent annual probability, maps were created using topographic data and water-surface elevations resulting from hydrologic and hydraulic analyses. The hydrologic analysis for the Omaha Creek study area was performed using historical peak flows obtained from the U.S. Geological Survey streamflow gage (station number 06601000). Flood frequency and magnitude were estimated using the PEAKFQ Log-Pearson Type III analysis software. The U.S. Army Corps of Engineers’ Hydrologic Engineering Center River Analysis System, version 3.1.3, software was used to simulate the water-surface elevation for flood events. The calibrated model was used to compute streamflow-gage stages and inundation elevations for the discharges corresponding to floods of selected probabilities. Results of the hydrologic and hydraulic analyses indicated that flood inundation elevations are substantially lower than from a previous study

Reexamination of decoherence in quantum walks on the hypercube

The effect of decoherence on the continuous-time quantum walk on the hypercube is revisited. Previously, an exact solution was found for a decoherence model that preserved the effective tensor-product form of the dynamics. Here a new model is presented, inspired by perfect quantum state transfer in qubit networks. A perturbative solution is found for the dynamics of this model which is not of a tensor-product form. In contrast to previous results, the hitting probability has a lower bound that is independent of the hypercube dimension.Comment: 8 pages, 4 figures, revised title and text for PR

The sovereign yield curve and credit ratings in GIIPS

© 2020 International Review of Finance Ltd. 2020 This paper studies the impact of sovereign credit rating and outlook changes on the shape of the sovereign yield curve using data for five European countries, namely, Greece, Ireland, Italy, Portugal, and Spain, known as the GIIPS for the period of 2001–2016. We use the dynamic Nelson–Siegel model to estimate the level, slope, and curvature of the yield curve. Subsequently, we employ the vector autoregressive model to estimate the effect of sovereign rating and outlook changes on the sovereign yield curve. We find a significant effect of rating downgrades and an insignificant effect of rating upgrades in all five countries; however, the results for the effect of changes in outlook status are mixed. Our results remain robust to various sensitivity tests

Strong-field effects in the Rabi oscillations of the superconducting phase qubit

Rabi oscillations have been observed in many superconducting devices, and represent prototypical logic operations for quantum bits (qubits) in a quantum computer. We use a three-level multiphoton analysis to understand the behavior of the superconducting phase qubit (current-biased Josephson junction) at high microwave drive power. Analytical and numerical results for the ac Stark shift, single-photon Rabi frequency, and two-photon Rabi frequency are compared to measurements made on a dc SQUID phase qubit with Nb/AlOx/Nb tunnel junctions. Good agreement is found between theory and experiment.Comment: 4 pages, 4 figures, accepted for publication in IEEE Trans. Appl. Supercon

Quantum logic gates for coupled superconducting phase qubits

Based on a quantum analysis of two capacitively coupled current-biased Josephson junctions, we propose two fundamental two-qubit quantum logic gates. Each of these gates, when supplemented by single-qubit operations, is sufficient for universal quantum computation. Numerical solutions of the time-dependent Schroedinger equation demonstrate that these operations can be performed with good fidelity.Comment: 4 pages, 5 figures, revised for publicatio