10 research outputs found
Mean-square optimal control of Linear Parameter Varying systems
The problem of designing parameter-dependent output feedback controllers by using inaccurate knowledge of the scheduling parameter is addressed in the paper. Discrete time Linear Parameter Varying (LPV) systems are considered with external scheduling variables corrupted by measurement noise. The paper investigates the optimal control of such LPV class in the quadratic mean-square sense. The solution of the controller design problem is obtained as a standard optimization problem subject to Linear Matrix Inequality (LMI) constraints. A comparative simulation example is given to illustrate the proposed methodology and underline the importance of embedding stochastic information in the LPV control design procedure
Mean-square optimal control of Linear Parameter Varying systems
The problem of designing parameter-dependent output feedback controllers by using inaccurate knowledge of the scheduling parameter is addressed in the paper. Discrete time Linear Parameter Varying (LPV) systems are considered with external scheduling variables corrupted by measurement noise. The paper investigates the optimal control of such LPV class in the quadratic mean-square sense. The solution of the controller design problem is obtained as a standard optimization problem subject to Linear Matrix Inequality (LMI) constraints. A comparative simulation example is given to illustrate the proposed methodology and underline the importance of embedding stochastic information in the LPV control design procedure
Reconstruction of plasma edge density profile from Lithium beam data using statistical analysis
[No abstract available
Photometric and radial-velocity time series of RR Lyrae stars in M3 : analysis of single-mode variables
We present the first simultaneous photometric and spectroscopic investigation
of a large set of RR Lyrae variables in a globular cluster. The radial-velocity
data presented comprise the largest sample of RVs of RR Lyrae stars ever
obtained. The target is M3; time-series of 111 and flux
data of further 64 RRab stars, and RV data of 79 RR Lyrae stars are published.
Blazhko modulation of the light curves of 47 percent of the RRab stars are
detected. The mean value of the center-of-mass velocities of RR Lyrae stars is
km s with 4.52 km s standard deviation, which is in good
agreement with the results obtained for the red giants of the cluster. The
phase difference of the RV curves of RRab stars is
found to be uniformly constant both for the M3 and for Galactic field RRab
stars; no period or metallicity dependence of the is
detected. The Baade-Wesselink distances of 26 non-Blazhko variables with the
best phase-coverage radial-velocity curves are determined; the corresponding
distance of the cluster, pc, agrees with the previous literature
information. A quadratic formula for the relation of
RRab stars is given, which is valid for both OoI and OoII variables. We also
show that the of RRab stars measured at light minimum is period
dependent, there is at least 0.1 mag difference between the colours at minimum
light of the shortest- and longest-period variables.Comment: 22 pages, 14 figures, accepted for publication in the Monthly Notices
of the Royal Astronomical Societ
Measuring Farmland Biodiversity
About one-third of the world\u2019s land surface is used for farming, a fact that bears important implications for biodiversity. In Europe, for instance, an estimated 50 percent of all wild species are reliant on agricultural habitats, while agricultural productivity often depends on the presence or absence of particular species. Despite this close coupling, surprisingly little is known about the status and evolution of farmland biodiversity. A team of European and African researchers, hoping to fill this gap in information, recently invented and piloted a new toolbox called the BioBio indicator set, which measures 23 different instances of biodiversity across a variety of farm types and scales in Europe. Applications were also tested in Tunisia, Ukraine, and Uganda, where they proved a feasible starting point for adaptation to the agricultural context of different countries
Les Houches 2011: Physics at TeV Colliders New Phys
We present the activities of the "New Physics" working group for the "Physics at TeV Colliders" workshop (Les Houches, France, 30 May-17 June, 2011). Our report includes new agreements on formats for interfaces between computational tools, new tool developments, important signatures for searches at the LHC, recommendations for presentation of LHC search results, as well as additional phenomenological studies
Second asymptomatic carotid surgery trial (ACST-2) : a randomised comparison of carotid artery stenting versus carotid endarterectomy
Background: Among asymptomatic patients with severe carotid artery stenosis but no recent stroke or transient cerebral ischaemia, either carotid artery stenting (CAS) or carotid endarterectomy (CEA) can restore patency and reduce long-term stroke risks. However, from recent national registry data, each option causes about 1% procedural risk of disabling stroke or death. Comparison of their long-term protective effects requires large-scale randomised evidence.
Methods: ACST-2 is an international multicentre randomised trial of CAS versus CEA among asymptomatic patients with severe stenosis thought to require intervention, interpreted with all other relevant trials. Patients were eligible if they had severe unilateral or bilateral carotid artery stenosis and both doctor and patient agreed that a carotid procedure should be undertaken, but they were substantially uncertain which one to choose. Patients were randomly allocated to CAS or CEA and followed up at 1 month and then annually, for a mean 5 years. Procedural events were those within 30 days of the intervention. Intention-to-treat analyses are provided. Analyses including procedural hazards use tabular methods. Analyses and meta-analyses of non-procedural strokes use Kaplan-Meier and log-rank methods. The trial is registered with the ISRCTN registry, ISRCTN21144362.
Findings: Between Jan 15, 2008, and Dec 31, 2020, 3625 patients in 130 centres were randomly allocated, 1811 to CAS and 1814 to CEA, with good compliance, good medical therapy and a mean 5 years of follow-up. Overall, 1% had disabling stroke or death procedurally (15 allocated to CAS and 18 to CEA) and 2% had non-disabling procedural stroke (48 allocated to CAS and 29 to CEA). Kaplan-Meier estimates of 5-year non-procedural stroke were 2·5% in each group for fatal or disabling stroke, and 5·3% with CAS versus 4·5% with CEA for any stroke (rate ratio [RR] 1·16, 95% CI 0·86-1·57; p=0·33). Combining RRs for any non-procedural stroke in all CAS versus CEA trials, the RR was similar in symptomatic and asymptomatic patients (overall RR 1·11, 95% CI 0·91-1·32; p=0·21).
Interpretation: Serious complications are similarly uncommon after competent CAS and CEA, and the long-term effects of these two carotid artery procedures on fatal or disabling stroke are comparable