Istituto Italiano di Tecnologia

About: Istituto Italiano di Tecnologia is a facility organization based out in Genoa, Italy. It is known for research contribution in the topics: Robot & Humanoid robot. The organization has 4561 authors who have published 14595 publications receiving 437558 citations. The organization is also known as: Italian Institute of Technology & IIT.

Two-dimensional Fröhlich interaction in transition-metal dichalcogenide monolayers: Theoretical modeling and first-principles calculations

Abstract: We perform ab initio calculations of the coupling between electrons and small-momentum polar-optical phonons in monolayer transition-metal dichalcogenides of the $2H$ type: ${\mathrm{MoS}}_{2},\phantom{\rule{0.28em}{0ex}}{\mathrm{MoSe}}_{2},\phantom{\rule{0.28em}{0ex}}{\mathrm{MoTe}}_{2},\phantom{\rule{0.28em}{0ex}}{\mathrm{WS}}_{2}$, and ${\mathrm{WSe}}_{2}$. The polar-optical coupling with longitudinal optical phonons, or Fr\"ohlich interaction, is fundamentally affected by the dimensionality of the system. In a plane-wave framework with periodic boundary conditions, the Fr\"ohlich interaction is affected by the spurious interaction between the two-dimensional (2D) material and its periodic images. To overcome this difficulty, we perform density functional perturbation theory calculations with a truncated Coulomb interaction in the direction perpendicular to the plane of the 2D material. We show that the two-dimensional Fr\"ohlich interaction is much stronger than assumed in previous ab initio studies. We provide analytical models depending on the effective charges and dielectric properties of the materials to interpret our ab initio calculations. Screening is shown to play a fundamental role in the phonon-momentum dependency of the polar-optical coupling, with a crossover between two regimes depending on the dielectric properties of the material relative to its environment. The Fr\"ohlich interaction is screened by the dielectric environment in the limit of small phonon momenta and sharply decreases due to stronger screening by the monolayer at finite momenta. The small-momentum regime of the ab initio Fr\"ohlich interaction is reproduced by a simple analytical model, for which we provide the necessary parameters. At larger momenta, however, direct ab initio calculations of electron-phonon interactions are necessary to capture band-specific effects. We compute and compare the carrier relaxation times associated with the scattering by both LO and ${A}_{1}$ phonon modes. While both modes are capable of relaxing carriers on time scales under the picosecond at room temperature, their absolute importance and relative importance vary strongly depending on the material, the band, and the substrate.

Cortical connections of the anterior (F5a) subdivision of the macaque ventral premotor area F5

Abstract: We traced the cortical connections of the anterior sector (F5a) of the macaque ventral premotor (PMv) area F5 and compared them with those of the adjacent F5 sectors, F5c and F5p F5a displays a very dense “intrinsic” connectivity with F5c and F5p, premotor connections limited to F4 and F6/pre-SMA, relatively robust prefrontal connections with areas 46v and 12, and dense connections with rostral opercular frontal areas Outside the frontal cortex, connections of F5a are dense with the SII region, relatively robust with inferior parietal areas PFG and AIP, weak with the inferior parietal area PF, and moderate with area 24 The comparison with data from injections in F5c and F5p showed that F5a, though sharing some common parietal connections with the other F5 sectors, displays several characterizing features providing robust evidence for its connectional distinctiveness The present study provides evidence for a general organization of the PMv similar to that of the medial and dorsal premotor cortex, with F5a representing a pre-PMv area Specifically, the present data suggest that F5a is a privileged site of integration, in the PMv, of parietal sensory-motor signals with higher-order information originating from prefrontal, rostral frontal opercular areas, and F6/pre-SMA The results of this integration can be then broadcasted to the adjacent F5 sectors for the generation and control of hand actions and cognitive motor functions

A biohybrid synapse with neurotransmitter-mediated plasticity

Abstract: Brain-inspired computing paradigms have led to substantial advances in the automation of visual and linguistic tasks by emulating the distributed information processing of biological systems1. The similarity between artificial neural networks (ANNs) and biological systems has inspired ANN implementation in biomedical interfaces including prosthetics2 and brain-machine interfaces3. While promising, these implementations rely on software to run ANN algorithms. Ultimately, it is desirable to build hardware ANNs4,5 that can both directly interface with living tissue and adapt based on biofeedback6,7. The first essential step towards biologically integrated neuromorphic systems is to achieve synaptic conditioning based on biochemical signalling activity. Here, we directly couple an organic neuromorphic device with dopaminergic cells to constitute a biohybrid synapse with neurotransmitter-mediated synaptic plasticity. By mimicking the dopamine recycling machinery of the synaptic cleft, we demonstrate both long-term conditioning and recovery of the synaptic weight, paving the way towards combining artificial neuromorphic systems with biological neural networks.

A Survey on Control of Hydraulic Robotic Manipulators With Projection to Future Trends

Abstract: This paper presents the recent advancements in the control of multiple-degree-of-freedom hydraulic robotic manipulators. A literature review is performed on their control, covering both free-space and constrained motions of serial and parallel manipulators. Stability-guaranteed control system design is the primary requirement for all control systems. Thus, this paper pays special attention to such systems. An objective evaluation of the effectiveness of different methods and the state of the art in a given field is one of the cornerstones of scientific research and progress. For this purpose, the maximum position tracking error $|e|_{\rm max}$ and a performance indicator $\rho$ (the ratio of $|e|_{\rm max}$ with respect to the maximum velocity) are used to evaluate and benchmark different free-space control methods in the literature. These indicators showed that stability-guaranteed nonlinear model based control designs have resulted in the most advanced control performance. In addition to stable closed-loop control, lack of energy efficiency is another significant challenge in hydraulic robotic systems. This paper pays special attention to these challenges in hydraulic robotic systems and discusses their reciprocal contradiction. Potential solutions to improve the system energy efficiency without control performance deterioration are discussed. Finally, for hydraulic robotic systems, open problems are defined and future trends are projected.