Search results for " Low"
showing 10 items of 972 documents
Adaptive Finite-Time Control for a Flexible Hypersonic Vehicle with Actuator Fault
2013
The problem of robust fault-tolerant tracking control is investigated. Simulation on the longitudinal model of a flexible air-breathing hypersonic vehicle (FAHV) with actuator faults and uncertainties is conducted. In order to guarantee that the velocity and altitude track their desired commands in finite time with the partial loss of actuator effectiveness, an adaptive fault-tolerant control strategy is presented based on practical finite-time sliding mode method. The adaptive update laws are used to estimate the upper bound of uncertainties and the minimum value of actuator efficiency factor. Finally, simulation results show that the proposed control strategy is effective in rejecting unc…
On the roadmap to supergrid in Sicily: LiDAR technology and HTLS conductors for uprating the 150 kV lines
2014
Difficulties in building new power lines in Italy because of authorization problems, and the production of electricity from renewable sources growing more and more, induces Terna S.p.A. (Italian TSO) to take advantage of existing overhead transmission lines. In order to increase the transmission capacity, Terna has used a software in GIS (Geographic Information System) environment which allows for the management of the interferences according to all the legislative bonds by referring to the LIDAR (Laser Imaging Detection and Ranging) remote sensing technology. This paper, after a description of the GIS and the LiDAR technology, shows how the calculation of the current capacity of some High …
Split-Delivery Capacitated Arc-Routing Problem: Lower Bound and Metaheuristic
2010
International audience; This paper proposes lower and upper bounds for the split-delivery capacitated arc-routing problem (SDCARP), a variant of the capacitated arc-routing problem in which an edge can be serviced by several vehicles. Recent papers on related problems in node routing have shown that this policy can bring significant savings. It is also more realistic in applications such as urban refuse collection, where a vehicle can become full in the middle of a street segment. This work presents the first lower bound for the SDCARP, computed with a cutting plane algorithm and an evolutionary local search reinforced by a multistart procedure and a variable neighborhood descent. Tests on …
Capacity Upper Bound of Channel Assembling in Cognitive Radio Networks with Quasistationary Primary User Activities
2013
In cognitive radio networks (CRNs) with multiple channels, various channel-assembling (ChA) strategies may be applied to secondary users (SUs), resulting in different achieved capacity. However, there is no previous work on determining the capacity upper bound (UB) of ChA for SUs under given system configurations. In this paper, we derive the maximum capacity for CRNs with ChA through Markov chain modeling, considering that primary user (PU) activities are relatively static, compared with SU services. We first deduce a closed-form expression for the maximum capacity in a dynamic ChA strategy and then demonstrate that no other ChA strategy can provide higher capacity than that achieved by th…
Reliable estimates in the anisotropic heat conduction problems
2014
Abstract The heat conduction problems for anisotropic bodies are studied taking into account the uncertainties in the material orientation. The best estimations of the upper and lower bounds of the considered energy dissipation functional are based on developing new approach consisting in solution of some optimization problems and finding the extremal internal material structures, which realize minimal and maximal dissipation. The motivation of this study comes from paper making processes, and more precisely, drying process, which consumes about 50% of the energy fed into the paper machine. The understanding of the effect of uncertainties in the process arises from structural properties of …
Attenuation of low frequency magnetic fields produced by HV underground power cables
2015
High-voltage underground cable systems are becoming more common as the demand for electrical power within urban centers increase, also considering the difficulties in building new overhead power lines in the vicinity of city centers because of authorization issues. Therefore, interest towards the evaluation of magnetic fields produced by high-voltage power lines has been triggered during the last decade and concern about effects on human health of exposure to extra low frequency (ELF) magnetic fields due to power lines has been increasing as well. Hence, the evaluation of the magnetic field produced by underground power cables is important in order to develop methods for mitigating their in…
Experiencing Urban Mining in an Italian Municipality towards a Circular Economy vision
2017
Abstract Selective waste collection in Italy has undergone significant changes over the last decade, highlighting very different approaches from one region to another. Research results presented in this paper are underlying differences between geographical regions and use them as a model of good practices to improve the less optimized systems. In the last decade, the Trento City Council has established a goal – the optimization of selective municipal solid waste collection – that led to a very low amount of recyclable materials in the residual fraction. More than that, for the first time sanitary textiles have been considered as a separable fraction at the source; for a long time this type …
A Methodology for the Design of MOS Current-Mode Logic Circuits
2010
In this paper, a design methodology for the minimization of various performance metrics of MOS Current-Mode Logic (MCML) circuits is described. In particular, it allows to minimize the delay under a given power consumption, the power consumption under a given delay and the power-delay product. Design solutions can be evaluated graphically or by simple and effective automatic procedures implemented within the MATLAB environment. The methodology exploits the novel concepts of crossing-point current and crossing-point capacitance. A useful feature of it is that it provides the designer with useful insights into the dependence of the performance metrics on design variables and fan-out capacitan…
Consensus-based Distributed Intrusion Detection for Multi-Robot Systems
2008
This paper addresses a security problem in robotic multi-agent systems, where agents are supposed to cooperate according to a shared protocol. A distributed Intrusion Detection System (IDS) is proposed here, that detects possible non-cooperative agents. Previous work by the authors showed how single monitors embedded on-board the agents can detect non- cooperative behavior, using only locally available information. In this paper, we allow such monitors to share the collected information in order to overcome their sensing limitation. In this perspective, we show how an agreement on the type of behavior of a target-robot may be reached by the monitors, through execution of a suitable consensu…
Glossing wind names in Low German in Salisbury? A newly discovered text in London, British Library, Cotton Vitellius A.xii
2018
It's an essay investigating a text on the names of the winds in ms London, British Library, Cotton Vitellius A.xii (s. xi), where both Latin and vernacular names are given. The text may ultimately derive from Einhard's Life of Charlemagne (ch. 29), but it appears as a self-contained text in the form of a Class Glossary. Although inserted in a manuscript copied in England at Salisbury, the vernacular words of the text are not in Old English. The essay makes a case for a possible connection with Flanders, with the text being one of the very rare surviving specimen of the Old Low Franconian language.