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No full textINGVPublished4.2. TTC - Modelli per la stima della pericolosità sismica a scala nazionale5.1. TTC - Banche dati e metodi macrosismiciope
Simultaneous Localization and Mapping Using the Phase of Passive UHF-RFID Signals
No full textAn indoor simultaneous localization and mapping (SLAM) problem for a mobile robot using the Radio Frequency IDentification (RFID) technology is considered. The system consists of a reader, installed on the robot, which measures the phase shift of the UHF-RFID signals coming from a set of passive tags deployed on the ceiling of the environment. The position of the tags is unknown and only an approximate knowledge of the ceiling height is available at the beginning. A Rao-Blackwellized Particle Filtering approach is proposed to fuse the RFID measurements with the robot odometry and to determine both the robot pose and the tag coordinates. Simulative and experimental results are reported to illustrate the effectiveness of the proposed approach: the precision obtained is in the order of a few cm
Control of manufacturing systems with a two-value, production-dependent failure rate
No full textIn this paper we consider a failure prone, single machine, single part-type, limited inventory, manufacturing system subject to a non-homogeneous Markov failure/repair process with the failure rate depending on the production rate through a two-value function. The problem is to minimize a cost function which includes a penalty for waiting customers. We derive and prove the optimality of a policy which depends on a threshold but is not the so-called hedging point policy, optimal for the Markov homogeneous case
A Robot Localization System Combining RSSI and Phase Shift in UHF-RFID Signals
No full textThis paper proposes a global indoor localization system based on the radio frequency identification (RFID) technology. A reader, installed on the robot, measures the received signal strength indication (RSSI) and the phase shift of UHF-RFID signals coming from a set of passive tags deployed on the ceiling of the environment. The position of the tags in the environment is only roughly known at the beginning. Exploiting the complementary features of RSSI and phase-shift information in RFID signals (together with odometry data), a multihypothesis extended and unscented Kalman filter is proposed to localize the robot and to simultaneously improve the initial estimate on the tag coordinates. The simulative and experimental results are reported to illustrate the effectiveness of the proposed approach
Robot Localization Using the Phase of Passive UHF-RFID Signals Under Uncertain Tag Coordinates
No full textAn indoor global localization problem for a mobile robot based on Radio Frequency IDentification (RFID) is considered. The localization system consists of a reader installed on the robot which measures the phase of UHF-RFID signals coming from a set of passive tags deployed on the ceiling of the environment. Assuming only an approximate information is available at the beginning on the position of the tags, this paper presents an algorithm, based on a Multi-Hypothesis Extended Kalman Filter, which improves the initial estimate on the tag coordinates while simultaneously localizing the robot. Simulative and experimental results are reported to illustrate the effectiveness of the proposed approach
Dynamic scheduling for a single machine system under different setup and buffer capacity scenarios
No full textJune 200
Comparison of finite volume canonical and grand canonical Gibbs measures under a mixing condition
No full textOn a front evolution problem for the multidimensional East model
Full text linkWe consider a natural front evolution problem for the East process on Z(d), d >= 2, a well studied kinetically constrained model for which the facilitation mechanism is oriented along the coordinate directions, as the equilibrium density q of the facilitating vertices vanishes. Starting with a unique unconstrained vertex at the origin, let S(t) consist of those vertices which became unconstrained within time t and, for an arbitrary positive direction x, let v(max)(x), v(min)(x) be the maximal/minimal velocities at which S(t) grows in that direction. If x is independent of q, we prove that v(max)(x) = v(min)(x)((1+o(1))) = gamma((1+o(1)))(d) as q -> 0, where gamma(d) is the spectral gap of the process on Z(d). We also analyse the case in which x depends on q and some of its coordinates vanish as q -> 0. In particular, for d = 2 we prove that if x approaches one of the two coordinate directions fast enough, then v(max)(x) = v(min)(x)((1+o(1))) = gamma((1+o(1)))(1) = gamma(d(1+o(1)))(d) , i.e. the growth of S(t) close to the coordinate directions is much slower than the growth in the bulk and it is dictated by the one dimensional process. As a result the region S(t) becomes extremely elongated inside Z(+)(d). We also establish mixing time cutoff for the chain in finite boxes with minimal boundary conditions. A key ingredient of our analysis is the renormalisation technique of [12] to estimate the spectral gap of the East process. A main novelty here is the extension of this technique to get the main asymptotic as q -> 0 of a suitable principal Dirichlet eigenvalue of the process
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