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11.
In this paper, we address the problem of output regulation for a broad class of multi‐input multi‐output (MIMO) nonlinear systems. Specifically, we consider input–affine systems, which are invertible and input–output linearizable. This class includes, as a trivial special case, the class of MIMO systems which possess a well‐defined vector relative degree. It is shown that if a system in this class is strongly minimum phase, in a sense specified in the paper, the problem of output regulation can be solved via partial‐state feedback or via (dynamic) output feedback. The result substantially broadens the class of nonlinear MIMO systems for which the problem in question is known to be possible. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
13.
José Hernández-Orallo Cèsar Ferri Nicolas Lachiche Adolfo Martínez-Usó M. José Ramírez-Quintana 《Data mining and knowledge discovery》2016,30(4):848-890
Some supervised tasks are presented with a numerical output but decisions have to be made in a discrete, binarised, way, according to a particular cutoff. This binarised regression task is a very common situation that requires its own analysis, different from regression and classification—and ordinal regression. We first investigate the application cases in terms of the information about the distribution and range of the cutoffs and distinguish six possible scenarios, some of which are more common than others. Next, we study two basic approaches: the retraining approach, which discretises the training set whenever the cutoff is available and learns a new classifier from it, and the reframing approach, which learns a regression model and sets the cutoff when this is available during deployment. In order to assess the binarised regression task, we introduce context plots featuring error against cutoff. Two special cases are of interest, the \( UCE \) and \( OCE \) curves, showing that the area under the former is the mean absolute error and the latter is a new metric that is in between a ranking measure and a residual-based measure. A comprehensive evaluation of the retraining and reframing approaches is performed using a repository of binarised regression problems created on purpose, concluding that no method is clearly better than the other, except when the size of the training data is small. 相似文献
14.
Torresani L Hertzmann A Bregler C 《IEEE transactions on pattern analysis and machine intelligence》2008,30(5):878-892
This paper describes methods for recovering time-varying shape and motion of non-rigid 3D objects from uncalibrated 2D point tracks. For example, given a video recording of a talking person, we would like to estimate the 3D shape of the face at each instant, and learn a model of facial deformation. Time-varying shape is modeled as a rigid transformation combined with a non-rigid deformation. Reconstruction is ill-posed if arbitrary deformations are allowed, and thus additional assumptions about deformations are required. We first suggest restricting shapes to lie within a low-dimensional subspace, and describe estimation algorithms. However, this restriction alone is insufficient to constrain reconstruction. To address these problems, we propose a reconstruction method using a Probabilistic Principal Components Analysis (PPCA) shape model, and an estimation algorithm that simultaneously estimates 3D shape and motion for each instant, learns the PPCA model parameters, and robustly fills-in missing data points. We then extend the model to model temporal dynamics in object shape, allowing the algorithm to robustly handle severe cases of missing data. 相似文献
15.
Sarv Ahrabi Sima Piazzo Lorenzo Momenzadeh Alireza Scarpiniti Michele Baccarelli Enzo 《The Journal of supercomputing》2022,78(9):12024-12045
The Journal of Supercomputing - We present a probabilistic method for classifying chest computed tomography (CT) scans into COVID-19 and non-COVID-19. To this end, we design and train, in an... 相似文献
16.
Paolini Emilio De Marinis Lorenzo Cococcioni Marco Valcarenghi Luca Maggiani Luca Andriolli Nicola 《Neural computing & applications》2022,34(18):15589-15601
Neural Computing and Applications - Photonics-based neural networks promise to outperform electronic counterparts, accelerating neural network computations while reducing power consumption and... 相似文献
17.
Nano Research - The widespread and increasing interest in enhancing biosensing technologies by increasing their sensitivities and lowering their costs has led to the exploration and application of... 相似文献
18.
A method of multichannel processing to compute correlation products simultaneously is introduced. The signals that process are encoded on a single light beam through the use of an electro-optic modulators that induce optical delays greater than the coherence length of light. The coherence-modulated light beam thus obtained is then spatially and temporally modulated through an acousto-optic Bragg cell. The potential number of channels is estimated to be approximately 5-10. The method can be combined with other existing systems, such as time-, space-, or frequency-multiplexed correlators, to increase the channel number. The method also applies to high-resolution spectral analysis. 相似文献
19.
Antonio Fernández Anta José Luis López-Presa M. Araceli Lorenzo Pilar Manzano Juan Martinez-Romo Alberto Mozo Christopher Thraves 《Theory of Computing Systems》2011,48(1):1-22
In this paper we generalize the Continuous Adversarial Queuing Theory (CAQT) model (Blesa et al. in MFCS, Lecture Notes in
Computer Science, vol. 3618, pp. 144–155, 2005) by considering the possibility that the router clocks in the network are not synchronized. We name the new model Non Synchronized
CAQT (NSCAQT). Clearly, this new extension to the model only affects those scheduling policies that use some form of timing.
In a first approach we consider the case in which although not synchronized, all clocks run at the same speed, maintaining
constant differences. In this case we show that all universally stable policies in CAQT that use the injection time and the
remaining path to schedule packets remain universally stable. These policies include, for instance, Shortest in System (SIS)
and Longest in System (LIS). Then, we study the case in which clock differences can vary over time, but the maximum difference
is bounded. In this model we show the universal stability of two families of policies related to SIS and LIS respectively
(the priority of a packet in these policies depends on the arrival time and a function of the path traversed). The bounds
we obtain in this case depend on the maximum difference between clocks. This is a necessary requirement, since we also show
that LIS is not universally stable in systems without bounded clock difference. We then present a new policy that we call
Longest in Queues (LIQ), which gives priority to the packet that has been waiting the longest in edge queues. This policy
is universally stable and, if clocks maintain constant differences, the bounds we prove do not depend on them. To finish,
we provide with simulation results that compare the behavior of some of these policies in a network with stochastic injection
of packets. 相似文献
20.
Giacomo Bucci Laura Carnevali Lorenzo Ridi Enrico Vicario 《International Journal on Software Tools for Technology Transfer (STTT)》2010,12(5):391-403
Oris is a tool for qualitative verification and quantitative evaluation of reactive timed systems, which supports modeling
and analysis of various classes of timed extensions of Petri Nets. As most characterizing features, Oris implements symbolic
state space analysis of preemptive Time Petri Nets, which enable schedulability analysis of real-time systems running under
priority preemptive scheduling; and stochastic Time Petri Nets, which enable an integrated approach to qualitative verification
and quantitative evaluation. In this paper, we present the current version of the tool and we illustrate its application to
two different case studies in the areas of qualitative verification and quantitative evaluation, respectively. 相似文献