1,721,330 research outputs found
VERSO UN RITORNO ALLA CULTURA? 2. OMBRE SUL FUTURO DELL'ECONOMIA E SUL FUTURO DELLA CLASSE DIRIGENTE
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Advances onto the Internet of Things: how ontologies make the Internet of Things meaningful
No full textThe title of this book is a pun on the use of the preposition “onto” with the aim of recalling “Ontology”, the term commonly adopted in the computer science community to indicate the study of the formal specification for organizing knowledge. In the field of knowledge engineering, Ontologies are used for modeling concepts and relationships on some domain. The year 2013 celebrates the twentieth anniversary of the World Wide Web. The simple network of hypermedia has transformed the world of communications with enormous implications on the social relationships. However, traditional World Wide Web is currently experiencing a challenging evolution toward the Internet of Things (IoT), today feasible thanks to the integration of pervasive technologies capable of sensing the environment. The most important contribution of IoT regards the possibility of enabling more efficient machine-to-machine cooperation. To such aim, ontologies represent the most suitable tool to enable transfer and comprehension of information among computer applications, even those designed and developed by unrelated people in different places. This book proposes a collection of contributions illustrating different applications following these directions and that are the outcomes of real experiences developed in the context of research projects.
Tackling Selfish Clients in Federated Learning
Full text linkFederated Learning (FL) is a distributed machine learning paradigm facilitating participants to collaboratively train a model without revealing their local data. However, when FL is deployed into the wild, some intelligent clients can deliberately deviate from the standard training process to make the global model inclined toward their local model, thereby prioritizing their local data distribution. We refer to this novel category of misbehaving clients as selfish. In this paper, we propose a Robust aggregation strategy for the FL server to mitigate the effect of Selfishness (in short RFL-Self). RFL-Self incorporates an innovative method to recover (or estimate) the true updates of selfish clients from the received ones, leveraging robust statistics (median of norms) of the updates at every round. By including the recovered updates in aggregation, our strategy offers strong robustness against selfishness. Our experimental results, obtained on MNIST and CIFAR-10 datasets, demonstrate that just 2% of clients behaving selfishly can decrease the accuracy by up to 36%, and RFL-Self can mitigate that effect without degrading the global model performance
MO-LCAO approach and Ab initio computations
No full textThe physical reliability and foundations of the Hund-Hückel MO-LCAO model, in which a molecular orbital (MO) is represented as a linear combination of atomic orbitals (LCAO), are examined in light of ab initio self-consistent field (SCF) computations with bases of various sizes. It is shown that appropriate linear transformations of the basis make evident a substructure of the relevant ab initio matrices and vectors that justifies the physical assumptions on which the MO-LCAO model rests. The main conceptual aspects, viz. hydrogen-like atomic orbitals, hybrids, localized orbitals, give a coherent picture, and the numerical data show that the contributions to occupied orbital energies ignored in the MO-LCAO model are actually small enough to justify their neglect in chemical structure studies. The numerical parameter values can therefore be read quantitatively in the ab initio results and the importance of the approximations made estimated. These conclusions have been drawn from studies on a variety of molecules with first- and second-row atoms. The well-established transferability of group properties in molecules suggests that they are generally valid. The claim that hybrids are method-independent, and therefore features of chemical reality at the orbital level, is discussed due to its relevance for comparisons of the stability of chemical bonds based on overlap. Of course, further work on questions such as electronegativities and promotion is needed. © 2006 Wiley Periodicals, Inc
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