1,085 research outputs found
A Positioning Algorithm and System Architecture for Indoor Location-based Wireless Services
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Deriving Regression Lines Without Calculus
No full textThis article, C.W. Puritz of the Royal Grammar School - High Wycombe, describes a method to calculate the least squares line algebraically. First, the author uses a numeric example, which uses calculus, then describes a simpler algebraic method. This is a great lesson plan for those instructors attempting to teach this method with having students with prior knowledge of calculus. The author uses a step by step approach to help best describe both the technique and subsequent ways to best teach this method
Development and optimisation of a duplex real-time reverse transcription quantitative PCR assay targeting the VP7 and NS2 genes of African horse sickness virus
No full textNucleotide sequences of 52 South African isolates of African horse sickness virus (AHSV) collected during 2004–2005 and including viruses of all nine AHSV serotypes, were used to design and develop a duplex real-time reverse transcription quantitative PCR (RT-PCR) assay targeting the VP7 (S8) and NS2 (S9) genes of AHSV. The assay was optimized for detection of AHSV in fresh and frozen blood of naturally infected horses. Assay performance was enhanced using random hexamers rather than gene-specific primers for RT, and with denaturation of double-stranded RNA in the presence of random hexamers. The assay was efficient with a linear range of at least five orders of magnitude. The analytical sensitivity of the assay was 132 copies of the target genes (4125 copies per ml of blood), and the assay was at least 10-fold more sensitive than virus isolation on BHK-21 cells. The assay was also highly specific because it did not detect related orbiviruses, such as bluetongue and equine encephalosis viruses.ID: S0166093410000893; M3: Article; Accession Number: S0166093410000893; Author: M. Quan (a, b, ⁎); Author: C.W. Lourens (a, b); Author: N.J. MacLachlan (c); Author: I.A. Gardner (d); Author: A.J. Guthrie (a); Affiliation: Equine Research Centre, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; Affiliation: Equine Viral Disease Laboratory, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; Affiliation: Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA; Keyword: African horse sickness virus; Keyword: Real-time quantitative RT-PCR; Keyword: VP7 gene; Keyword: NS2 gene; Keyword: Duplex; Number of Pages: 8; Language: English
Nota, betreffende berekeningen omtrent rivierverbeteringen: opgemaakt door den ingenieur van den Rijkswaterstaat C.W. Lely
No full textHydraulische basis voor de normalisatiewerken van de grote rivieren. Berekingen van optimale breedte en diepte
Onderzoek naar signaalgeneratie met behulp van fasedraaiers ten behoeve van reflectie-compensatie in een F.M.-C.W. radarsysteem
No full textVoor onderzoek aan de troposfeer wordt gebruik gemaakt van een F.M.-C.W. radarsysteem. Een aspect van het radarsysteem waarnaar nog onderzoek gewenst is, is de onderdrukking van de overspraak van zender naar ontvanger, en van sterke reflecties aan nabije obstakels: deze signalen houden nl. het gevaar in van oversturing van de ontvanger. Dit aspect is met name van belang voor een mogelijk nog te realiseren F.M. -C.V. radarsysteem met één antenne…Applied SciencesElectrotechniekTelecommunicatie- en Verkeersbegeleidingssysteme
A Fourier-Based Valuation Method for Bermudan and Barrier Options under Heston’s Model
Full text linkWe develop an efficient Fourier-based numerical method for pricing Bermudan and discretely monitored barrier options under the Heston stochastic volatility model. The two-dimensional pricing problem is dealt with by a combination of a Fourier cosine series expansion, as in [F. Fang and C.W. Oosterlee, SIAM J. Sci. Comput., 31 (2008), pp. 826–848, F. Fang and C. W. Oosterlee, Numer. Math., 114 (2009), pp. 27–62], and high-order quadrature rules in the other dimension. Error analysis and experiments confirm a fast error convergence.Delft Institute of Applied MathematicsElectrical Engineering, Mathematics and Computer Scienc
Nota betreffende het verband tusschen bodemhelling en kromtestraal bij rivieren, opgemaakt door den ingenieur van den Rijkswaterstaat dr. C.W. Lely
No full textRelatie kromtestraal en dwarshelling van rivieren, bevat data van de Nederlandse rivieren
A Steam voyage to Contantinople by the Rhine and the Danube in 1840-41, and to Portugal, Spain etc in 1839. By C.W. Vane Marquess of Londonderry, G.C.B. to which is annexed, the author's correspondence with Prince Metternich, Lords Pondonby, Palmerston, I
No full textAppendix.Dedication: by the author to V.L. (his wife)Content description: Detailed contentsIllustration: 2 (Views ,varia ,)Pagination: PP13+354P, PP9+354PVolumes: 2Edition:1stText Genre:Prose / Letters / JournalIllustration: 2 (τοπία ,άλλα θέματα ,
Reduced-Order Modelling for Production Optimisation
No full textProduction optimisation of a reservoir simulation problem can be very computationally demanding as the reservoir model may contain many variables and nonlinearities, thus many iterations may be needed to obtain an optimal production schedule. Using Proper Orthogonal Decomposition and Trajectory Piecewise Linearization (POD-TPWL) developed in [1] and [2], simulations were performed on the Delft Egg model 100-200 times faster than the high-fidelity simulation with reasonable accuracy, depending on the distance from the trained solution. Production optimisation was performed using the gradient-based adjoint method. A reduced version of the adjoint equation was used by incorporating POD, as presented in [3] and by performing a first-order Taylor series expansion around a training point (similar to TPWL). This method allowed for time gains of 50-100 times when compared to the high-fidelity adjoint method. The results from the high-fidelity production optimisation compared with POD-TPWL showed a similar Net Present Value (NPV) for both optimisation methods, with an error of 0.1% between the two-values. However, the optimal injection schedules were not the same. When the high-fidelity model was run using the input schedules from POD-TPWL optimisation, the error in NPV was 4%. The speed-up observed for the optimisation loop using POD-TPWL was 6 times faster than the high-fidelity model. This is due to the number of snapshots that needed to be generated and the processing of the data from these snapshots. Robust optimisation was performed on the Egg model ensemble using a POD-TPWL model incorporating geological model parameters, states and well controls. Results showed a 0.7% deviation from the mean NPV value calculated in MoReS and a 4 million dollar increase in the standard deviation of the NPV. POD-TPWL was able to complete the robust optimisation 25 times faster than a high-fidelity simulation. POD-TPWL shows promise as a reduced-order modelling application for reservoir simulation and production optimisation. The accuracy needs to be improved in order to move to an operational application.Petroleum EngineeringGeoscience & EngineeringCivil Engineering and Geoscience
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