21,238 research outputs found
Service Performance Indicators for Infrastructure Investment
Infrastructure systems serving modern economies are highly complex, highly interconnected, and often highly
interactive. The result is increased complexity in investment decision-making, and increased challenges in prioritising
that investment. However, this prioritisation is vital to developing a long-term, sound, robust and achievable pipeline
of national infrastructure.
One key to effective, objective and prudent investment prioritisation is understanding the real performance of
infrastructure. Many metrics are employed to this end, and many are imposed by governments or regulators, but
often these metrics relate only to inputs or outputs in a production process. Whilst these metrics may be useful for
delivery agencies, they largely fail to address the real expectations or requirements of infrastructure users — quality of
service, safety, reliability, and resilience.
What is required is a set of metrics which address not outputs but outcomes — that is, how well does the
infrastructure network meet service needs? This paper reports on a study undertaken at a national level, to identify
service needs across a range of infrastructure sectors, to assess service performance metrics in use, and to show
how they or other suitable metrics can be used to prioritise investment decisions across sectors and jurisdictions
Regression analysis with missing data and unknown colored noise: application to the MICROSCOPE space mission
The analysis of physical measurements often copes with highly correlated
noises and interruptions caused by outliers, saturation events or transmission
losses. We assess the impact of missing data on the performance of linear
regression analysis involving the fit of modeled or measured time series. We
show that data gaps can significantly alter the precision of the regression
parameter estimation in the presence of colored noise, due to the frequency
leakage of the noise power. We present a regression method which cancels this
effect and estimates the parameters of interest with a precision comparable to
the complete data case, even if the noise power spectral density (PSD) is not
known a priori. The method is based on an autoregressive (AR) fit of the noise,
which allows us to build an approximate generalized least squares estimator
approaching the minimal variance bound. The method, which can be applied to any
similar data processing, is tested on simulated measurements of the MICROSCOPE
space mission, whose goal is to test the Weak Equivalence Principle (WEP) with
a precision of . In this particular context the signal of interest is
the WEP violation signal expected to be found around a well defined frequency.
We test our method with different gap patterns and noise of known PSD and find
that the results agree with the mission requirements, decreasing the
uncertainty by a factor 60 with respect to ordinary least squares methods. We
show that it also provides a test of significance to assess the uncertainty of
the measurement.Comment: 12 pages, 4 figures, to be published in Phys. Rev.
Terrain Database Correlation Assessment Using an Open Source Tool
Configuring networked simulators for training military teams in a distributed
environment requires the usage of a set of terrain databases to represent the
same training area. The results of simulation exercises can be degraded if the
terrain databases are poorly correlated. A number of methodologies for
determining the correlation between terrain databaHowever, there are few
computational tools for this task and most of them were developed to address
government needs, have limited availability, and handle specific digital
formats. The goal of this paper is thus to present a novel open source tool
developed as part of an academic research project.Comment: 12 pages, I/ITSEC 201
Superconducting charge qubits from a microscopic many-body perspective
The quantised Josephson junction equation that underpins the behaviour of
charge qubits and other tunnel devices is usually derived through cannonical
quantisation of the classical macroscopic Josephson relations. However, this
approach may neglect effects due to the fact that the charge qubit consists of
a superconducting island of finite size connected to a large superconductor.
We show that the well known quantised Josephson equation can be derived
directly and simply from a microscopic many-body Hamiltonian. By choosing the
appropriate strong coupling limit we produce a highly simplified Hamiltonian
that nevertheless allows us to go beyond the mean field limit and predict
further finite-size terms in addition to the basic equation.Comment: Accepted for J Phys Condensed Matte
Towards a knowledge-based system to assist the Brazilian data-collecting system operation
A study is reported which was carried out to show how a knowledge-based approach would lead to a flexible tool to assist the operation task in a satellite-based environmental data collection system. Some characteristics of a hypothesized system comprised of a satellite and a network of Interrogable Data Collecting Platforms (IDCPs) are pointed out. The Knowledge-Based Planning Assistant System (KBPAS) and some aspects about how knowledge is organized in the IDCP's domain are briefly described
Vascular risks in external sinus lifts: an anatomical approach
Abstract in proceedings of the Fourth International Congress of CiiEM: Health, Well-Being and Ageing in the 21st Century, held at Egas Moniz’ University Campus in Monte de Caparica, Almada, from 3–5 June 2019.This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.info:eu-repo/semantics/publishedVersio
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