The low frequency facility, a Virgo R&D experiment, is composed by a Fabry–Perot cavity attached and controlled by the Virgo suspension; the goal is to measure the thermal noise of the apparatus ...above 10 Hz, with a displacement sensitivity as high as 10
−18 m
/
Hz
. Since September 2001 the apparatus, located inside the INFN-Pisa experimental area, has been completely built and put into operation. Vacuum facilities and the control loops have been set up. Transfer functions, necessary to control the cavity, absolute test mass displacement and the first demonstration of the cavity locking are reported.
Status of Virgo Amico, P; Alshourbagy, M; Avino, S ...
Journal of Physics: Conference Series,
05/2006, Letnik:
39, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The gravitational wave detector Virgo commissioning started in autumn 2003. The main commissioning goal is to reach stable operation at the design sensitivity, significantly extended to the low ...frequency range starting from 10 Hz. However, the Collaboration's efforts during the last commissioning phase will also be aimed at the data exchange with other detectors operating with comparable sensitivity. The present status of the detector and the short term planning are outlined in this paper
A parallel in-time analysis system for Virgo Amico, P; Alshourbagy, M; Avino, S ...
Journal of Physics: Conference Series,
03/2006, Letnik:
32, Številka:
1
Journal Article, Conference Proceeding
Recenzirano
Odprti dostop
The interferometric gravitational wave detector Virgo is currently completing its commissioning phase and it is close to start scientific observations. Among the signals to be searched for, those ...emitted by coalescing binary systems are particularly promising and require a considerable computational effort to optimally search the parameter space. The Virgo collaboration has decided to implement an on-line analysis strategy capable of processing the interferometer data in-time. In this communication we present a component of the analysis pipeline, a parallel computing system based on the Message Passing Interface (MPI). We describe its capabilities, underlining its strength and flexibility, and we illustrate its relation with the other components of the pipeline. The on-line analysis chain, including the presented parallel system, has been run for the first time successfully during the Virgo commissioning run C5 in December 2nd to December 6th 20041.
This paper addresses the problem of ensuring trustworthy computation in a linear consensus network. A solution to this problem is relevant for several tasks in multi-agent systems including motion ...coordination, clock synchronization, and cooperative estimation. In a linear consensus network, we allow for the presence of misbehaving agents, whose behavior deviate from the nominal consensus evolution. We model misbehaviors as unknown and unmeasurable inputs affecting the network, and we cast the misbehavior detection and identification problem into an unknown-input system theoretic framework. We consider two extreme cases of misbehaving agents, namely faulty (non-colluding) and malicious (Byzantine) agents. First, we characterize the set of inputs that allow misbehaving agents to affect the consensus network while remaining undetected and/or unidentified from certain observing agents. Second, we provide worst-case bounds for the number of concurrent faulty or malicious agents that can be detected and identified. Precisely, the consensus network needs to be 2 k +1 (resp. k +1) connected for k malicious (resp. faulty) agents to be generically detectable and identifiable by every well behaving agent. Third, we quantify the effect of undetectable inputs on the final consensus value. Fourth, we design three algorithms to detect and identify misbehaving agents. The first and the second algorithm apply fault detection techniques, and affords complete detection and identification if global knowledge of the network is available to each agent, at a high computational cost. The third algorithm is designed to exploit the presence in the network of weakly interconnected subparts, and provides local detection and identification of misbehaving agents whose behavior deviates more than a threshold, which is quantified in terms of the interconnection structure.
Our ability to manipulate the behavior of complex networks depends on the design of efficient control algorithms and, critically, on the availability of an accurate and tractable model of the network ...dynamics. While the design of control algorithms for network systems has seen notable advances in the past few years, knowledge of the network dynamics is a ubiquitous assumption that is difficult to satisfy in practice. In this paper we overcome this limitation, and develop a data-driven framework to control a complex network optimally and without any knowledge of the network dynamics. Our optimal controls are constructed using a finite set of data, where the unknown network is stimulated with arbitrary and possibly random inputs. Although our controls are provably correct for networks with linear dynamics, we also characterize their performance against noisy data and in the presence of nonlinear dynamics, as they arise in power grid and brain networks.
Solar photovoltaic (PV) can help meet the growing demand for clean electricity in Arizona. This paper answers where solar PV development has taken place in Arizona, how much suitable land is ...available for utility-scale PV development, and how future land cover changes can affect the availability of this suitable land. PV development suitability scores are calculated for the land across Arizona based on topography, location, solar resource and public opinion factors. Ground truthing is used to identify the scenario which best explains Arizona's PV power plant developments from several decision-making scenarios. Less than two percent of Arizona's land is considered Excellent for PV development. Most of this land is private land or owned by state trust. If the available suitable land is fully developed with solar PV, Arizona has the potential to become a regional energy hub. However, in the next few decades suitable areas for solar PV generation can get rapidly depleted due to conflict with growing urban areas. If the suitable land for PV generation is not set-aside, Arizona would then have to depend on less suitable lands, look for multi-purpose land use options and distributed PV deployments to meet its future energy need.
•Solar PV development is proposed to meet the growing demand for clean electricity in Arizona and in western USA.•The study identifies suitable land for utility scale PV development in Arizona.•GIS (Geographic Information System) and Multi-Criteria Analysis (MCA) are used.•With the current available land for Solar PV, Arizona can meet its future energy demand and also be a regional energy hub.•As urban Arizona grows with time, the land suitable for PV development would reduce significantly.I
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