1,721,101 research outputs found
Distributed stochastic nonconvex optimization and learning based on successive convex approximation
No full textWe study distributed stochastic nonconvex optimization in multi-agent networks. We introduce a novel algorithmic framework for the distributed minimization of the sum of the expected value of a smooth (possibly nonconvex) function-the agents' sum-utility-plus a convex (possibly nonsmooth) regularizer. The proposed method hinges on successive convex approximation (SCA) techniques, leveraging dynamic consensus as a mechanism to track the average gradient among the agents, and recursive averaging to recover the expected gradient of the sumutility function. Almost sure convergence to (stationary) solutions of the nonconvex problem is established. Finally, the method is applied to distributed stochastic training of neural networks. Numerical results confirm the theoretical claims, and illustrate the advantages of the proposed method with respect to other methods available in the literature
Distributed nonconvex optimization over networks
No full textWe study nonconvex distributed optimization in multi-agent networks. We introduce a novel algorithmic framework for the distributed minimization of the sum of a smooth (possibly nonconvex) function-the agents' sum-utility-plus a convex (possibly nonsmooth) regularizer. The proposed method hinges on successive convex approximation (SCA) techniques while leveraging dynamic consensus as a mechanism to distribute the computation among the agents. Asymptotic convergence to (stationary) solutions of the nonconvex problem is established. Numerical results show that the new method compares favorably to existing algorithms on both convex and nonconvex problems
The regulations relating to heterologous artificial insemination following the ruling of the constitutional court [La disciplina della fecondazione eterologa dopo la pronuncia della Consulta]
No full textLa malattia cariosa nel bambino: segno di trascuratezza?
No full textLa comunicazione ha per argomento la carie nel bambino come possibile segno di trascuratezza
What is Similar in Music? A Comparison Between Behavioral and Mathematic Classifications of Musical Distances
No full textSparse distributed learning based on diffusion adaptation
No full textThis article proposes diffusion LMS strategies for distributed estimation over adaptive networks that are able to exploit sparsity in the underlying system model. The approach relies on convex regularization, common in compressive sensing, to enhance the detection of sparsity via a diffusive process over the network. The resulting algorithms endow networks with learning abilities and allow them to learn the sparse structure from the incoming data in real-time, and also to track variations in the sparsity of the model. We provide convergence and mean-square performance analysis of the proposed method and show under what conditions it outperforms the unregularized diffusion version. We also show how to adaptively select the regularization parameter. Simulation results illustrate the advantage of the proposed filters for sparse data recovery
Enabling prediction via multi-layer graph inference and sampling
No full textIn this work we propose a novel method to efficiently predict dynamic signals over both space and time, exploiting the theory of sampling and recovery of band-limited graph signals. The approach hinges on a multi-layer graph topology, where each layer refers to a spatial map of points where the signal is observed at a given time, whereas different layers pertain to different time instants. Then, a dynamic learning method is employed to infer space-time relationships among data in order to find a band-limited representation of the observed signal over the multi-layer graph. Such a parsimonious representation is then instrumental to use sampling theory over graphs to predict the value of the signal on a future layer, based on the observations over the past graphs. The method is then tested on a real data-set, which contains the outgoing cellular data traffic over the city of Milan. Numerical simulations illustrate how the proposed approach is very efficient in predicting the calls activity over a grid of nodes at a given daily hour, based on the observations of previous traffic activity over both space and time
Reporting
No full textDrafting an exam comprehensively requires the acquisition of: Personal data. Anamnesis. Indication for examination (specifying if the investigation is aimed at screening or if there is a specific indication). The execution of the examination starts with the observation of uterine morphology, the number of fetuses, and study of fetal anatomy and biometrics. It is necessary to study all the fetal system and characteristics of the placenta and umbilical cord. The fetal measurements should be included in growth nomograms and evaluated in centiles. At the end of the report the sonographer must express his diagnostic consideration and, sometimes, request other consultancy. It is useful to indicate the number of images given and when a new check is useful. It is useful to archive a copy of the entire examination
Doubt: Recognition or diagnostic accuracy?
No full textWe evaluate if it is correct to express the concept of diagnostic accuracy as it is almost always considered, i.e., as the sonographer's ability to recognize that specific malformation in a specific age of gestation (for example in mid-gestation). Since the malformation almost always manifests itself in a different manner as from anatomical point of view and above all in the time. In fact, the same malformation sometimes becomes visible early, sometimes late, sometimes grossly, and sometimes minimally. For this reason it is believed that the method of diagnostic accuracy used up to now must be changed and indicate how many times that anomaly is already present in that gestational age. The sonographer is also invited to always document the anatomical and biometric well-being and always keep the images or film of the ultrasound examination in the archive so as to be able to demonstrate, in medical-legal litigation, whether that fetal malformation was already present at the moment when the ultrasound examination was performed
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