1,721,008 research outputs found
Can a robot elicit emotions? A Global Optimization Model to attribute mental states to human users in HRI∗
No full textIn this work, we are interested in investigating if a distinct personality of the robot may impact the emotional state of the users, which we propose to detect using neuroscience theories that allow us to classify emotions based on valence and arousal metrics derived from brain wave activity analysis. We devised an experimental research study in which EEG data was gathered while individuals interacted with a robot with different personalities. Support Vector Machine, Decision Tree, Random Forest, K-Nearest Neighbors, and Multi-Layer Perceptrons have all been trained using EEG-signal, valence, and arousal data. All proposed classifiers were subjected to a Global optimization Model (GOM) that used feature selection and hyper-parameter optimization techniques to improve classification results and address common issues that affect classifier accuracy when attempting to solve a supervised learning problem, such as bias-variance trade-off, dimensionality of the input space, and noise in the input data space. The findings of the experiments will be presented and debated
Machian Effects Inside a Rotating Spherical Shell
No full textAbstract: During typical general relativity courses, the gravitational fields generated by rotating objects and the so-called frame dragging effect are explained by emphasizing the presence of a gravitational Coriolis-like force term. It is well known that, in a rotating system, there is also a fictitious centrifugal force. In general, textbooks do not discuss also the possibility of a gravitational centrifugal-like force, and, in a recent paper, we have analyzed the presence of a repulsive force in the vicinity of a rotating mass. Now, however, we want to reviews some historical aspects of Mach’s Principle and to analyze the centrifugal gravitational term inside a rotating spherical shell, with a new simple approach
A Two-Level Atom in the Field of a de Broglie Gravitational Wave
No full textde Broglie gravitational waves represent a classical realization of a form of dynamics that was proposed by de Broglie at the beginning of the last century. They are oscillations of spacetime with an effective mass, which is responsible for longitudinal effects that are absent in standard gravitational waves. In this article we study the influence of this gravitational field on a two-level atom in a semiclassical way. We will work out a gauge independent expression of the effective potential describing such interaction and we will use it to compute the transition amplitude between two quantum states. For a two-level hydrogen atom we will find an example of gravitational qubit, meaning that the quantum system exhibits periodic transitions between the states (Rabi oscillations) in analogy to the case of electromagnetic interaction. As an application, we will consider a gravity wave associated to a neutrino and we will estimate the transition frequency
An evolution of the universe based on a modified time-redshift relation can avoid the introduction of a cosmological constant
No full textInspired by the recent literature, we study the Einstein–de Sitter cosmological model coupled with a generalization of the relation between the redshift and time dilation of the kind δt0=δte(1+z)n. We find that this model fits the experimental data regarding 1048 supernovae, in a way which is competitive with the standard ΛCDM model and without the need of introducing a non-zero cosmological constant. Since the existence of dark energy, as a main ingredient of the composition of the cosmos, is still under debate, we propose our formalism as an example of an alternative description of the cosmological scenario
On the dynamics of a test particle in the field of the de Broglie gravitational waves
No full textThe de Broglie gravitational waves are a solution of the linearized Einstein equations with properties that are absent in the standard gravity waves because they are also longitudinal waves and obey a dispersion relation that leads to an effective mass. Furthermore, they represent a classical realization of a form of dynamics, proposed for quantum particles by de Broglie in 1927. In this paper, we discuss the dynamics of a massive particle in presence of the de Broglie gravity wave. We will compute the analytical expression for the linear and angular momentum of the corpuscle. As an application, we will consider the case in which these oscillations of spacetime are associated to an electron travelling with a velocity equal to 1% of the light speed and we will estimate the order of magnitude of the quantities involved. We will show that a nearby positron oscillates and radiates an energy of 1eV in 10-5s, an effect that is, in principle, measurable
On the polarization states of the de Broglie gravitational wave
No full textThe pilot-wave theory is an alternative, but less used, interpretation of Quantum Mechanics. In that framework, elementary particles are guided by a wave and move along well defined trajectories. A fascinating idea is the possibility to describe the de Broglie wave as oscillations of the gravitational field, thereby giving geometrical meaning to the pilot-wave of a quantum corpuscle. In this work we will investigate the polarizations of the de Broglie gravitational wave and we will find that the spin-2 metric perturbation breaks down into two tensor (helicity-2), two vector (helicity-1) and two scalar (helicity-0) components. We will show that these dynamical variables satisfy the equation of the harmonic oscillator, meaning that they represent the physical degrees of freedom of the wave. We will also propose a method to measure the scalar modes, containing longitudinal components that are absent in standard transverse gravitational waves
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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