The uncertainty enabled model web (UncertWeb)

UncertWeb is a European research project running from 2010-2013 that will realize the uncertainty enabled model web. The assumption is that data services, in order to be useful, need to provide information about the accuracy or uncertainty of the data in a machine-readable form. Models taking these data as imput should understand this and propagate errors through model computations, and quantify and communicate errors or uncertainties generated by the model approximations. The project will develop technology to realize this and provide demonstration case studies.

Verification of the indoor gps system by comparison with points calibrated using a network of laser tracker measurements

This paper details a method of determining the uncertainty of dimensional measurement for a three dimensional coordinate measurement machine. An experimental procedure was developed to compare three dimensional coordinate measurements with calibrated reference points. The reference standard used to calibrate these reference points was a fringe counting interferometer with the multilateration technique employed to establish three dimensional coordinates. This is an extension of the established technique of comparing measured lengths with calibrated lengths. Specifically a distributed coordinate measurement device was tested which consisted of a network of Rotary-Laser Automatic Theodolites (R-LATs), this system is known commercially as indoor GPS (iGPS). The method was found to be practical and able to establish that the expanded uncertainty of the basic iGPS system was approximately 1 mm at a 95% confidence level. © Springer-Verlag Berlin Heidelberg 2010.

Distributed temperature sensor based on Brillouin loss in an optical fibre for transient threshold monitoring

A distributed temperature sensor for transient threshold monitoring with a 22 km sensing length, based on the Brillouin loss in standard communications fibre, is demonstrated. The system can be used for real-time monitoring of a preset temperature threshold. Good S/N ratios were achieved with only 8–16 sample averages giving a response time of 2 to 4 s with a temperature uncertainty of ±1 °C.

El reencuentro de la música española con la Latinomérica poscolonial:el caso Joaquín Sabina

La música se convirtió en los años setenta en el medio para encauzar la oposición al régimen franquista y la incertidumbre ante la transición. Del ejemplo y la fascinación con la revolución cubana, a la oposición a las dictaduras chilena (1973), uruguaya (1974) y argentina (1976), todos ellos fueron hechos que en España se vivieron como propios. En esos años los cantautores españoles reivindicaban la libertad de expresión y el final de todas las dictaduras. Sin embargo, la música española comienza a transformar su mirada hacia Latinoamérica cuando la democracia es un hecho. Se representa ahora un nuevo espacio latinoamericano que me propongo caracterizar en este artículo, y a través del caso concreto de Joaquín Sabina, como "post-colonial".The music in the seventies became the vehicle for channeling opposition to the regime and the uncertainty of the transition. From the example and the fascination with the Cuban revolution, opposition to the dictatorships in Chile (1973), Uruguay (1974) and Argentina (1976), they were all events that were lived in Spain as their own. In those years the Spanish songwriters claiming freedom of expression and end of all dictatorships. However, the Spanish music begins to turn their attention to Latin America where democracy is a fact. It is now a new Latin American space I propose to characterize in this article, and through the specific case of Joaquin Sabina, as "post-colonial".J A brief survey of style to your work reflects his role as poet cult following in the wake of Herrera or Gongora, as did Antequerana School, aims to upgrade from his vivid descriptions, his Christian ideas and a lyrical formal mannerisms full of clichés.

Distributed temperature sensor based on Brillouin loss in an optical fibre for transient threshold monitoring

A distributed temperature sensor for transient threshold monitoring with a 22 km sensing length, based on the Brillouin loss in standard communications fibre, is demonstrated. The system can be used for real-time monitoring of a preset temperature threshold. Good S/N ratios were achieved with only 8–16 sample averages giving a response time of 2 to 4 s with a temperature uncertainty of ±1 °C.

Orthodoxy confirmed, but at what cost?

Examines the Court of Appeal ruling in Mexfield Housing Co-operative Ltd v Berrisford on whether a periodic tenancy agreement concluded by a housing association, which purported to prohibit the landlord from seeking possession unless the tenant was in arrears of rent, or otherwise in breach, could be terminated by way of a notice to quit, even where no breach had occurred, on the ground of uncertainty of term. Considers whether the agreement could be enforced under the rules of equity.

Probabilistic control for uncertain systems

In this paper a new framework has been applied to the design of controllers which encompasses nonlinearity, hysteresis and arbitrary density functions of forward models and inverse controllers. Using mixture density networks, the probabilistic models of both the forward and inverse dynamics are estimated such that they are dependent on the state and the control input. The optimal control strategy is then derived which minimizes uncertainty of the closed loop system. In the absence of reliable plant models, the proposed control algorithm incorporates uncertainties in model parameters, observations, and latent processes. The local stability of the closed loop system has been established. The efficacy of the control algorithm is demonstrated on two nonlinear stochastic control examples with additive and multiplicative noise.

Distribución espacial de la incertidumbre en mapas de cubiertas obtenidos mediante teledetección

When combining remote sensing imagery with statistical classifiers to obtain categorical thematic maps it is not usual to provide data about the spatial distribution of the error and uncertainty of the resulting maps. This paper describes, in the context of GeoViQua FP7 project, feasible approaches for methods based on several steps such as hybrid classifiers. Both for “per pixel” and “per polygon” strategies, the proposal is based on the use of the available ground truth, which is used to properly model the spatial distribution of the errors. Results allow mapping the classification success with a very high level of reliability (R2>0,94), providing users a sound knowledge of the accuracy at every area of the map.

Assembly accuracy analysis for small components with a planar surface in large-scale metrology

Large-scale mechanical products, such as aircraft and rockets, consist of large numbers of small components, which introduce additional difficulty for assembly accuracy and error estimation. Planar surfaces as key product characteristics are usually utilised for positioning small components in the assembly process. This paper focuses on assembly accuracy analysis of small components with planar surfaces in large-scale volume products. To evaluate the accuracy of the assembly system, an error propagation model for measurement error and fixture error is proposed, based on the assumption that all errors are normally distributed. In this model, the general coordinate vector is adopted to represent the position of the components. The error transmission functions are simplified into a linear model, and the coordinates of the reference points are composed by theoretical value and random error. The installation of a Head-Up Display is taken as an example to analyse the assembly error of small components based on the propagation model. The result shows that the final coordination accuracy is mainly determined by measurement error of the planar surface in small components. To reduce the uncertainty of the plane measurement, an evaluation index of measurement strategy is presented. This index reflects the distribution of the sampling point set and can be calculated by an inertia moment matrix. Finally, a practical application is introduced for validating the evaluation index.

Comparative performance between two photogrammetric systems and a reference laser tracker network for large-volume industrial measurement

This paper determines the capability of two photogrammetric systems in terms of their measurement uncertainty in an industrial context. The first system – V-STARS inca3 from Geodetic Systems Inc. – is a commercially available measurement solution. The second system comprises an off-the-shelf Nikon D700 digital camera fitted with a 28 mm Nikkor lens and the research-based Vision Measurement Software (VMS). The uncertainty estimate of these two systems is determined with reference to a calibrated constellation of points determined by a Leica AT401 laser tracker. The calibrated points have an average associated standard uncertainty of 12·4 μm, spanning a maximum distance of approximately 14·5 m. Subsequently, the two systems’ uncertainty was determined. V-STARS inca3 had an estimated standard uncertainty of 43·1 μm, thus outperforming its manufacturer's specification; the D700/VMS combination achieved a standard uncertainty of 187 μm.

iGPS capability study

This report presents the results of testing of the Metris iGPS system performed by the National Physical Laboratory (NPL) and the University of Bath (UoB), with the assistance of Metris, and Airbus at Airbus, Broughton in March 2008. The aim of the test was to determine the performance capability of the iGPS coordinate metrology system by comparison with a reference measurement system based on multilateration implemented using laser trackers. A network of reference points was created using SMR nests fixed to the ground and above ground level on various stands. The reference points were spread out within the measurement volume of approximately 10 m ´ 10 m ´ 2 m. The coordinates of each reference point were determined by the laser tracker survey using multilateration. The expanded uncertainty (k=2) in the relative position of these reference coordinates was estimated to be of the order of 10 µm in x, y and z. A comparison between the iGPS system and the reference system showed that for the test setup, the iGPS system was able to determine lengths up to 12 m with an uncertainty of 170 µm (k=2) and coordinates with an uncertainty of 120 µm in x and y and 190 µm in z (k=2).