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Multitask feature selection within structural datasets
- Sarah Bee, Jack Poole, Keith Worden, Nikolaos Dervilis, Lawrence Bull
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- Journal:
- Data-Centric Engineering / Volume 5 / 2024
- Published online by Cambridge University Press:
- 07 March 2024, e4
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Population-based structural health monitoring (PBSHM) systems use data from multiple structures to make inferences of health states. An area of PBSHM that has recently been recognized for potential development is the use of multitask learning (MTL) algorithms that differ from traditional single-task learning. This study presents an application of the MTL approach, Joint Feature Selection with LASSO, to provide automatic feature selection. The algorithm is applied to two structural datasets. The first dataset covers a binary classification between the port and starboard side of an aircraft tailplane, for samples from two aircraft of the same model. The second dataset covers normal and damaged conditions for pre- and postrepair of the same aircraft wing. Both case studies demonstrate that the MTL results are interpretable, highlighting features that relate to structural differences by considering the patterns shared between tasks. This is opposed to single-task learning, which improved accuracy at the cost of interpretability and selected features, which failed to generalize in previously unobserved experiments.
Cosmology with Phase 1 of the Square Kilometre Array Red Book 2018: Technical specifications and performance forecasts
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- Square Kilometre Array Cosmology Science Working Group:, David J. Bacon, Richard A. Battye, Philip Bull, Stefano Camera, Pedro G. Ferreira, Ian Harrison, David Parkinson, Alkistis Pourtsidou, Mário G. Santos, Laura Wolz, Filipe Abdalla, Yashar Akrami, David Alonso, Sambatra Andrianomena, Mario Ballardini, José Luis Bernal, Daniele Bertacca, Carlos A. P. Bengaly, Anna Bonaldi, Camille Bonvin, Michael L. Brown, Emma Chapman, Song Chen, Xuelei Chen, Steven Cunnington, Tamara M. Davis, Clive Dickinson, José Fonseca, Keith Grainge, Stuart Harper, Matt J. Jarvis, Roy Maartens, Natasha Maddox, Hamsa Padmanabhan, Jonathan R. Pritchard, Alvise Raccanelli, Marzia Rivi, Sambit Roychowdhury, Martin Sahlén, Dominik J. Schwarz, Thilo M. Siewert, Matteo Viel, Francisco Villaescusa-Navarro, Yidong Xu, Daisuke Yamauchi, Joe Zuntz
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- Journal:
- Publications of the Astronomical Society of Australia / Volume 37 / 2020
- Published online by Cambridge University Press:
- 06 March 2020, e007
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We present a detailed overview of the cosmological surveys that we aim to carry out with Phase 1 of the Square Kilometre Array (SKA1) and the science that they will enable. We highlight three main surveys: a medium-deep continuum weak lensing and low-redshift spectroscopic HI galaxy survey over 5 000 deg2; a wide and deep continuum galaxy and HI intensity mapping (IM) survey over 20 000 deg2 from $z = 0.35$ to 3; and a deep, high-redshift HI IM survey over 100 deg2 from $z = 3$ to 6. Taken together, these surveys will achieve an array of important scientific goals: measuring the equation of state of dark energy out to $z \sim 3$ with percent-level precision measurements of the cosmic expansion rate; constraining possible deviations from General Relativity on cosmological scales by measuring the growth rate of structure through multiple independent methods; mapping the structure of the Universe on the largest accessible scales, thus constraining fundamental properties such as isotropy, homogeneity, and non-Gaussianity; and measuring the HI density and bias out to $z = 6$ . These surveys will also provide highly complementary clustering and weak lensing measurements that have independent systematic uncertainties to those of optical and near-infrared (NIR) surveys like Euclid, LSST, and WFIRST leading to a multitude of synergies that can improve constraints significantly beyond what optical or radio surveys can achieve on their own. This document, the 2018 Red Book, provides reference technical specifications, cosmological parameter forecasts, and an overview of relevant systematic effects for the three key surveys and will be regularly updated by the Cosmology Science Working Group in the run up to start of operations and the Key Science Programme of SKA1.
4 - Nitrogen in current European policies
- from Part I - Nitrogen in Europe: the present position
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- By Oene Oenema, Wageningen University and Research Centre, Albert Bleeker, Energy Research Centre of the Netherlands, Nils Axel Braathen, OECD, France, Michaela Budňáková, Ministry of Agriculture of the Czech Republic, Keith Bull, Centre for Ecology and Hydrology Lancaster Environment Centre, Pavel Čermák, Central Institute for Supervising and Testing in Agriculture, Markus Geupel, Federal Environment Agency, Germany, Kevin Hicks, University of York, Robert Hoft, Convention on Biological Diversity, Natalia Kozlova, North-West Research Institute, Adrian Leip, European Commission Joint Research Centre, Till Spranger, Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Laura Valli, CRPA, Italy, Gerard Velthof, Wageningen University and Research Centre, Wilfried Winiwarter, International Institute for Applied Systems Analysis
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 62-81
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Summary
Executive summary
Nature of the problem
Europe, and especially the European Union (EU), has many governmental policy measures aimed at decreasing unwanted reactive nitrogen (Nr) emissions from combustion, agriculture and urban wastes. Many of these policy measures have an ‘effects-based approach’, and focus on single Nr compounds, single sectors and either on air or waters.
This chapter addresses the origin, objectives and targets of EU policy measures related to Nr emissions, considers which instruments are being used to implement the policies and briefly discusses the effects of the policy measures.
Approaches
The chapter starts with a brief description of the basic elements of governmental policy measures.
A review of the main international conventions and EU policies related to emissions of Nr to air and water is then provided.
Finally the chapter provides a semi-quantitative assessment of the effectiveness and efficiency of European policy measures.
Key findings/state of knowledge
International conventions and other treaties have played a key role in raising awareness and establishing policy measures for Nr emissions abatement in EU through so-called Directives and Regulations.
There are many different EU Directives, often addressing individual Nr compounds from individual sectors (e.g. NOx emissions from combustion; NH3 emissions from agriculture, pollution of groundwater and surface water by nitrates from agriculture, discharge of total nitrogen from urban sewage to surface waters).
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25 - Coordinating European nitrogen policies between international conventions and intergovernmental organizations
- from Part V - European nitrogen policies and future challenges
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- By Keith Bull, Centre for Ecology and Hydrology Lancaster Environment Centre, Robert Hoft, Convention on Biological Diversity, Mark A. Sutton, Centre for Ecology and Hydrology
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp 570-584
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Summary
Executive summary
Nature of the problem
International treaties, such as multilateral environmental agreements (MEAs), have sought to protect the environment by intergovernmental action on many issues.
The MEAs and intergovernmental organizations (IGOs) have, between them, targeted most known environmental problems, but none has tackled nitrogen management holistically since the nitrogen issue is much broader than any of the individual interests.
Even so, several conventions have taken action to develop nitrogen policies in their specific areas of interest, but they are often limited in their options to increase their scope of action beyond their agreed mandates and may be reluctant to coordinate action with those of others.
As a result, there remains a need to develop an integrated, holistic approach for nitrogen management; an international treaty targeted explicitly on nitrogen would have the potential to bring the different elements of the nitrogen problem together.
Approaches
Some coordination between MEAs and IGOs already occurs with regard to different nitrogen threats, but the focus is inevitably on areas of overlapping interests. This chapter explores the potential for available mechanisms to be applied further across these institutions to harmonize work and to promote effective coordination on nitrogen-related threats and abatement options.
Summary for policy makers
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- By Mark A. Sutton, Centre for Ecology and Hydrology, Hans van Grinsven, Netherlands Environmental Assessment Agency, Gilles Billen, University Pierre & Marie Curie, Albert Bleeker, Energy Research Centre of the Netherlands, Alexander F. Bouwman, Netherlands Environmental Assessment Agency, Keith Bull, Centre for Ecology and Hydrology Lancaster Environment Centre, Jan Willem Erisman, Energy Research Centre of the Netherlands, Peringe Grennfelt, IVL Swedish Environmental Research Institute Ltd, Bruna Grizzetti, European Commission Joint Research Centre, Clare M. Howard, Centre for Ecology and Hydrology, Oene Oenema, Wageningen University and Research Centre, Till Spranger, Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, Wilfried Winiwarter, International Institute for Applied Systems Analysis
- Edited by Mark A. Sutton, NERC Centre for Ecology and Hydrology, UK, Clare M. Howard, NERC Centre for Ecology and Hydrology, UK, Jan Willem Erisman, Gilles Billen, Albert Bleeker, Peringe Grennfelt, Hans van Grinsven, Bruna Grizzetti
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- Book:
- The European Nitrogen Assessment
- Published online:
- 16 May 2011
- Print publication:
- 14 April 2011, pp xxiv-xxxiv
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Summary
Main messages
Too much nitrogen harms the environment and the economy
Over the past century humans have caused unprecedented changes to the global nitrogen cycle, converting atmospheric di-nitrogen (N2) into many reactive nitrogen (Nr) forms, doubling the total fixation of Nr globally and more than tripling it in Europe.
The increased use of Nr as fertilizer allows a growing world population, but has considerable adverse effects on the environment and human health. Five key societal threats of Nr can be identified: to water quality, air quality, greenhouse balance, ecosystems and biodiversity, and soil quality.
Cost–benefit analysis highlights how the overall environmental costs of all Nr losses in Europe (estimated at €70–€320 billion per year at current rates) outweigh the direct economic benefits of Nr in agriculture. The highest societal costs are associated with loss of air quality and water quality, linked to impacts on ecosystems and especially on human health.
Nitrogen cascade and budgets
The different forms of Nr inter-convert through the environment, so that one atom of Nr may take part in many environmental effects, until it is immobilized or eventually denitrified back to N2. The fate of anthropogenic Nr can therefore be seen as a cascade of Nr forms and effects. The cascade highlights how policy responses to different Nr forms and issues are inter-related, and that a holistic approach is needed, maximizing the abatement synergies and minimizing the trade-offs.
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