1,002 research outputs found
Subtraction of temperature induced phase noise in the LISA frequency band
Temperature fluctuations are expected to be one of the limiting factors for
gravitational wave detectors in the very low frequency range. Here we report
the characterisation of this noise source in the LISA Pathfinder optical bench
and propose a method to remove its contribution from the data. Our results show
that temperature fluctuations are indeed limiting our measurement below one
millihertz, and that their subtraction leads to a factor 5.6 (15 dB) reduction
in the noise level at the lower end of the LISA measurement band 10^{-4} Hz,
which increases to 20.2 (26 dB) at even lower frequencies, i.e., 1.5x10^{-5}
Hz. The method presented here can be applied to the subtraction of other noise
sources in gravitational wave detectors in the general situation where multiple
sensors are used to characterise the noise source.Comment: 8 pages, 6 figure
Naphthalene Adsorption on 13X Molecular Sieve
In this paper, naphthalene adsorption on 13X molecular sieve has been investigated. The isotherms and the net heat of adsorption have been determined in the range between 40 °C and 380 °C. Analysis of the results clearly indicates that the Dubinin-Radushkevitch model provides the best fitting equation for data points, with a specific limitation due to some steric hindrance effect
Determinación ponderal de fibras en una mezcla y relación entre diametro y densidad aparente de la lana
Se hace un estudio crítico de los métodos corrientemente empleados en análisis de mezclas de fibras por microscopía, haciendo notar la imposibilidad de poder obtener resultados relativamente exactos al analizar mezclas en las que algunos de sus componentes son fibras celulósicas o proteicas, debido a que en los cálculos intervienen datos como el diámetro y la densidad de las mismas.
El primero es determinado sin tener en cuenta que la fibra presenta poros sensibles dando lugar a un volumen aparente que al ser mayor que el volumen real (volumen de masa fibrilar sin huecos), hace que tenga que considerarse una densidad aparente, necesariamente menor que la real.
El trabajo se orientó en el sentido de hallar un método factible de poder determinar la densidad aparente de cada fibra, con objeto de utilizarla en las fórmulas y método de análisis por contaje ya establecidos.
Se determinó la densidad aparente de la lana en sus distintos tipos, encontrándose una correlación entre el diámetro y la densidad aparente, de la cual se deduce la ecuación analítica que liga estas dos variablesPeer Reviewe
Integrating clinicians, knowledge and data: expert-based cooperative analysis in healthcare decision support
<p>Abstract</p> <p>Background</p> <p>Decision support in health systems is a highly difficult task, due to the inherent complexity of the process and structures involved.</p> <p>Method</p> <p>This paper introduces a new hybrid methodology <it>Expert-based Cooperative Analysis </it>(EbCA), which incorporates explicit prior expert knowledge in data analysis methods, and elicits implicit or tacit expert knowledge (IK) to improve decision support in healthcare systems. EbCA has been applied to two different case studies, showing its usability and versatility: 1) Bench-marking of small mental health areas based on technical efficiency estimated by <it>EbCA-Data Envelopment Analysis (EbCA-DEA)</it>, and 2) Case-mix of schizophrenia based on functional dependency using <it>Clustering Based on Rules (ClBR)</it>. In both cases comparisons towards classical procedures using qualitative explicit prior knowledge were made. Bayesian predictive validity measures were used for comparison with expert panels results. Overall agreement was tested by Intraclass Correlation Coefficient in case "1" and kappa in both cases.</p> <p>Results</p> <p>EbCA is a new methodology composed by 6 steps:. 1) Data collection and data preparation; 2) acquisition of "Prior Expert Knowledge" (PEK) and design of the "Prior Knowledge Base" (PKB); 3) PKB-guided analysis; 4) support-interpretation tools to evaluate results and detect inconsistencies (here <it>Implicit Knowledg </it>-IK- might be elicited); 5) incorporation of elicited IK in PKB and repeat till a satisfactory solution; 6) post-processing results for decision support. EbCA has been useful for incorporating PEK in two different analysis methods (DEA and Clustering), applied respectively to assess technical efficiency of small mental health areas and for case-mix of schizophrenia based on functional dependency. Differences in results obtained with classical approaches were mainly related to the IK which could be elicited by using EbCA and had major implications for the decision making in both cases.</p> <p>Discussion</p> <p>This paper presents EbCA and shows the convenience of completing classical data analysis with PEK as a mean to extract relevant knowledge in complex health domains. One of the major benefits of EbCA is iterative elicitation of IK.. Both explicit and tacit or implicit expert knowledge are critical to guide the scientific analysis of very complex decisional problems as those found in health system research.</p
Ergodic and non-ergodic clustering of inertial particles
We compute the fractal dimension of clusters of inertial particles in mixing
flows at finite values of Kubo (Ku) and Stokes (St) numbers, by a new series
expansion in Ku. At small St, the theory includes clustering by Maxey's
non-ergodic 'centrifuge' effect. In the limit of St to infinity and Ku to zero
(so that Ku^2 St remains finite) it explains clustering in terms of ergodic
'multiplicative amplification'. In this limit, the theory is consistent with
the asymptotic perturbation series in [Duncan et al., Phys. Rev. Lett. 95
(2005) 240602]. The new theory allows to analyse how the two clustering
mechanisms compete at finite values of St and Ku. For particles suspended in
two-dimensional random Gaussian incompressible flows, the theory yields
excellent results for Ku < 0.2 for arbitrary values of St; the ergodic
mechanism is found to contribute significantly unless St is very small. For
higher values of Ku the new series is likely to require resummation. But
numerical simulations show that for Ku ~ St ~ 1 too, ergodic 'multiplicative
amplification' makes a substantial contribution to the observed clustering.Comment: 4 pages, 2 figure
HLA
Définition du système HLA Le système HLA situé sur le Chromosome 6 est composé de gènes dits de Classe I (HLA-A, -B, -C) et dits de Classe II (HLA-DP, -DQ et -DR). Les molécules HLA ont pour fonction de présenter des peptides (qu’ils soient des antigènes autologues, c’est-à-dire propres à l’individu, ou d’origine étrangère comme ceux des micro-organismes). Un autre point commun entre ces deux classes de molécules est qu’elles présentent un extrême polymorphisme. Ce polymorphisme est l’une des..
HLA
Définition du système HLA Le système HLA situé sur le Chromosome 6 est composé de gènes dits de Classe I (HLA-A, -B, -C) et dits de Classe II (HLA-DP, -DQ et -DR). Les molécules HLA ont pour fonction de présenter des peptides (qu’ils soient des antigènes autologues, c’est-à-dire propres à l’individu, ou d’origine étrangère comme ceux des micro-organismes). Un autre point commun entre ces deux classes de molécules est qu’elles présentent un extrême polymorphisme. Ce polymorphisme est l’une des..
Towards a FPGA-controlled deep phase modulation interferometer
Deep phase modulation interferometry was proposed as a method to enhance
homodyne interferometers to work over many fringes. In this scheme, a
sinusoidal phase modulation is applied in one arm while the demodulation takes
place as a post-processing step. In this contribution we report on the
development to implement this scheme in a fiber coupled interferometer
controlled by means of a FPGA, which includes a LEON3 soft-core processor. The
latter acts as a CPU and executes a custom made application to communicate with
a host PC. In contrast to usual FPGA-based designs, this implementation allows
a real-time fine tuning of the parameters involved in the setup, from the
control to the post-processing parameters.Comment: Proceedings of the X LISA Symposium, Gainesville, May 18-23, 201
Practical considerations for the design of an aeroelastic energy harvester
Achieving the optimal balance between weight and energy consumption during flight mission remains a challenge for the design of very efficient high altitude long endurance aircrafts (HALE). These aircraft are intended to have flight missions that can range from 30 to 90 days. Composite materials are used to provide the structural integrity of the aircraft while minimizing its weight. Typically composites are used in long and slender structural elements of the HALE and are the main drivers of dynamic aeroelastic instabilities, even at low speed. This is due to the higher structural flexibility they introduce. Therefore, in order to respond to the demand of HALE aircrafts of having a wider amount of energy on board, without any substantial weight penalization, an experimental piezoelectric wing have been designed with the aim of exploiting aeroelastic instabilities or any other type of induced vibrations to generate electric energy directly on board. The numerical model of the piezoelectric wing, presented in this paper, is built starting from the assumptions of the 3D Euler-Bernoulli beam theory and of the strip theory for the aerodynamic loads. A preliminary sensitivity study was carried out, over the flutter solutions, for the identification of a suitable experimental prototype, to be used for modal and wind tunnel tests. The test campaign showed a good agreement between numerical and experiments results, highlighting, above all, the encouraging results in terms of energy harvesting and in terms of the exploitation potential of the piezoelectric design in the dynamic of structures
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