1,721,414 research outputs found
Replication Data for: Structure of personal networks and cognitive abilities: A study on a sample of Italian older adults
No full textThis dataset allows replication of the analyses reported in the article "Structure of personal networks and cognitive abilities: a study on a sample of Italian older adults". The aim was to test the positive association between the number of cohesive sub-groups in personal networks and cognitive functioning among older adults. The dataset was built from survey data collected in 2019-2020 on a convenience sample of older adults aged 75 and older
Viewpoint: Artificial Intelligence accidents waiting to happen?
Full text linkArtificial Intelligence (AI) is at a crucial point in its development: stable enough to be used in production systems, and increasingly pervasive in our lives. What does that mean for its safety? In his book Normal Accidents, the sociologist Charles Perrow proposed a framework to analyze new technologies and the risks they entail. He showed that major accidents are nearly unavoidable in complex systems with tightly coupled components if they are run long enough. In this essay, we apply and extend Perrow’s framework to AI to assess its potential risks. Today’s AI systems are already highly complex, and their complexity is steadily increasing. As they become more ubiquitous, different algorithms will interact directly, leading to tightly coupled systems whose capacity to cause harm we will be unable to predict. We argue that under the current paradigm, Perrow’s normal accidents apply to AI systems and it is only a matter of time before one occurs
ODINS: On-Demand Indoor Navigation System RFID Based
No full textThis paper presents an On-Demand Indoor Navigation System (ODINS) based on RFID technology. ODINS is a distributed infrastructure where a set of information points (Fixed Stations-FS) provides the direction to a user who has to reach the destination point he/she has previously selected. ODINS system is proposed for residencies hosting people with mild cognitive disabilities and elderly but it can be also applied to structures where people could be disoriented. The destination is configured at some reception points or it is a predefined (e.g. the bed room or a selected 'safe' point). The destination is associated with a RFID disposable bracelet assigned to her/him. The path is algorithmically computed and spread to all FSs. Every time the user is disoriented, she/he can search for the closest FS that displays the right directition. FSs should be located in strategic positions and provide a user-friendly interface such as bright arrows. The complexity is 'system-side' making ODINS usable for everyone
A randomized approach to switched nonlinear systems identification
Full text linkThis paper addresses the identification of Switched Nonlinear AutoRegressive eXogenous (SNARX) systems characterized as a collection of nonlinear dynamical systems (modes), each one described via a discrete time Nonlinear AutoRegressive eXogenous (NARX) model, indexed by a discrete-valued variable (switching signal). We propose a novel approach which, given a realization of the input/output signals collected from the system, jointly classifies the data attributing them to the different modes, and identifies the model structure and parameters for each mode. The involved optimization problem is partly combinatorial due to the data classication over modes and the model structure selection, and partly continuous due to the parameter estimation required to complete the identification of the dynamical models assigned to the different modes. A probabilistic framework is employed to address the problem, where Categorical and Bernoulli distributions are respectively used for the assignment
of modes over time and for the structure selection of the NARX models describing the modes. A randomized procedure is then proposed to solve the problem, based on a sample-and-evaluate strategy that progressively refines the induced SNARX model probability distribution. The
approach is tested on a numerical example taken from the literature, where it shows promising results
FEEL-IT: emotion and sentiment classification for the Italian language
Full text linkNo abstract availabl
Vehicle-to-Grid and ancillary services: a profitability analysis under uncertainty*
Full text linkThe rapid and massive diffusion of electric vehicles poses new challenges to the electric system, which must be able to supply these new loads, but at the same time opens up new opportunities thanks to the possible provision of ancillary services. Indeed, in the so-called Vehicle-to-Grid (V2G) set-up, the charging power can be modulated throughout the day so that a fleet of vehicles can absorb an excess of power from the grid or provide extra power during a shortage. To this end, many works in the literature focus on the optimization of each vehicle daily charging profiles to offer the requested ancillary services while guaranteeing a charged battery for each vehicle at the end of the day. However, the size of the economic benefits related to the provision of ancillary services varies significantly with the modeling approaches, different assumptions, and considered scenarios. In this paper we propose a profitability analysis with reference to a recently proposed framework for V2G optimal operation in presence of uncertainty. We provide necessary and sufficient conditions for profitability in a simplified case and we show via simulation that they also hold for the general case
Identification of switched nonlinear ARX systems using a randomized algorithm
No full textThe identification of switched nonlinear systems is a mixed discrete and continuous optimization problem that involves complex combinatorial problems, such as the selection of the local model structures and the estimation of the switching signal. In particular, switchings can occur at any time, which makes the combinatorial complexity of the latter task increase exponentially with the number of data. In this work, we employ a randomized scheme to estimate the switching locations: a probability distribution is used to represent the locations of a finite number of switchings and a sample-andevaluate strategy is employed to tune it. This strategy smoothly integrates with a previously developed randomized method devoted to the identification of the nonlinear local models and the mode switching sequence to produce a full switched system identification method. The proposed solution has been tested on a benchmark example to verify its effectiveness and efficiency compared to existing works
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