A framework for safe human-humanoid coexistence

This work is focused on the development of a safety framework for Human-Humanoid coexistence, with emphasis on humanoid locomotion. After a brief introduction to the fundamental concepts of humanoid locomotion, the two most common approaches for gait generation are presented, and are extended with the inclusion of a stability condition to guarantee the boundedness of the generated trajectories. Then the safety framework is presented, with the introduction of different safety behaviors. These behaviors are meant to enhance the overall level of safety during any robot operation. Proactive behaviors will enhance or adapt the current robot operations to reduce the risk of danger, while override behaviors will stop the current robot activity in order to take action against a particularly dangerous situation. A state machine is defined to control the transitions between the behaviors. The behaviors that are strictly related to locomotion are subsequently detailed, and an implementation is proposed and validated. A possible implementation of the remaining behaviors is proposed through the review of related works that can be found in literature

Skilled Migration, FDI and Human Capital Investment

It is commonly believed that accumulation of human capital (HC) and availability of physical and financial capitals are among the major determinants of economic growth. In a globalised world, where factors of production are increasingly mobile, the process of domestic accumulation of HC might be affected in several ways through migration and capital inflows. Furthermore, endowment of skilled labour and foreign direct investments (FDI) may reinforce each other through possible “complementary effects”. Our paper aims to advance the existing empirical literature on the relationship between international factor mobility and domestic accumulation of HC in developing countries. We provide new evidence on how the presence of foreign firms in the domestic economy and the emigration of skilled workers impact the domestic school enrolment. We also investigate whether existing supply of skilled labour is a significant determinant of inward flows of foreign capital. The interdependence between factor mobility and HC accumulation supports some simple back-of-the-envelop calculations aiming to investigate the presence of a virtuous (vicious) circle between HC accumulation and FDI inflows.Human Capital Investment, Factor Mobility, FDI, Brain Drain/Gain, Complementarity Effects, Developing Countries

MPC-based humanoid pursuit-evasion in the presence of obstacles

We consider a pursuit-evasion problem between humanoids in the presence of obstacles. In our scenario, the pursuer enters the safety area of the evader headed for collision, while the latter executes a fast evasive motion. Control schemes are designed for both the pursuer and the evader. They are structurally identical, although the objectives are different: the pursuer tries to align its direction of motion with the line- of-sight to the evader, whereas the evader tries to move in a direction orthogonal to the line-of-sight to the pursuer. At the core of the control architecture is a Model Predictive Control scheme for generating a stable gait. This allows for the inclusion of workspace obstacles, which we take into account at two levels: during the determination of the footsteps orientation and as an explicit MPC constraint. We illustrate the results with simulations on NAO humanoids

Humanoid gait generation for walk-to locomotion using single-stage MPC

We consider the problem of gait generation for a humanoid robot that must walk to an assigned Cartesian goal. As a first solution, we consider a rather straightforward adaptation of our previous work: An external block produces high-level velocities, which are then tracked by a double-stage intrinsically stable MPC scheme where the orientation of the footsteps is chosen before determining their location and the CoM trajectory. The second solution, which represents the main contribution of the paper, is conceptually different: no high-level velocity is generated, and footstep orientations are chosen at the same time of the other decision variables in a singlestage MPC. This is made possible by carefully redesigning the motion constraints so as to preserve linearity. Preliminary results on a simulated NAO confirm that the single-stage method outperforms the conventional double-stage scheme

Nutations in growing plant shoots: the role of elastic deformations due to gravity loading

Abstract The effect of elastic deformations induced by gravity loading on the active circumnutation movements of growing plant shoots is investigated. We consider first a discrete model (a gravitropic spring-pendulum system) and then a continuous rod model which is analyzed both analytically (under the assumption of small deformations) and numerically (in the large deformation regime). We find that, for a choice of material parameters consistent with values reported in the available literature on plant shoots, rods of sufficient length may exhibit lateral oscillations of increasing amplitude, which eventually converge to limit cycles. This behavior strongly suggests the occurrence of a Hopf bifurcation, just as for the gravitropic spring-pendulum system, for which this result is rigorously established. At least in this restricted set of material parameters, our analysis supports a view of Darwin's circumnutations as a biological analogue to structural systems exhibiting flutter instabilities, i.e., spontaneous oscillations away from equilibrium configurations driven by non-conservative loads. Here, in the context of nutation movements of growing plant shoots, the energy needed to sustain oscillations is continuously supplied to the system by the internal biochemical machinery presiding the capability of plants to maintain a vertical pose

Calibration of Soil Amplification Factors for Real-Time Ground-Motion Scenarios in Italy

This study deals with the calibration of soil amplification factors to be used for generating site-specific, real-time (or quasi real-time) ground-motion scenarios in Italy. To this end, the ground response of 100 soil profiles is studied through 1-dimensional (1D) equivalent-linear numerical simulations. Several real, rock ground-motion time histories, grouped into different peak ground acceleration (PGA) classes, are driven through the models of the soil columns. Soil amplification factors are then calculated using different definitions, either as the ratio of the spectral acceleration at the surface to the spectral acceleration at the rock outcrop or by dividing the (acceleration or pseudo-velocity) response spectrum intensity at the surface to the reference response spectrum intensity. Finally, regression analyses are performed to derive empirical equations that relate the amplification factor to different soil parameters, such as the average shear wave velocity VS,30 in the top 30 m of a soil profile and the soil fundamental frequency, f0. The reliability of the amplification factors here calculated is verified through comparison with experimental data recorded during the April 6, 2009 L’Aquila earthquake (Mw = 6.3)

Breakdown of gauge invariance in ultrastrong-coupling cavity QED

We revisit the derivation of Rabi- and Dicke-type models, which are commonly used for the study of quantum light-matter interactions in cavity and circuit QED. We demonstrate that the validity of the two-level approximation, which is an essential step in this derivation, depends explicitly on the choice of gauge once the system enters the ultrastrong coupling regime. In particular, while in the electric dipole gauge the two-level approximation can be performed as long as the Rabi frequency remains much smaller than the energies of all higher-lying levels, it can dramatically fail in the Coulomb gauge, even for systems with an extremely anharmonic spectrum. We extensively investigate this phenomenon both in the single-dipole (Rabi) and multi-dipole (Dicke) case, and considering the specific examples of dipoles confined by double-well and by square-well potentials, and of circuit QED systems with flux qubits coupled to an LC resonator.Comment: See also related independent work arxiv:1805.0635

Occurrence of Ganoderma adspersum on Pinus pinea

During a survey in a pine stand in Rome, six basidiomes of Ganoderma adspersum were collected from declining 50-60 year-old Pinus pinea. Species identification was accomplished through observation of macroscopic and microscopic morphological traits. Furthermore, ITS sequences of the collected specimens, 28 samples collected elsewhere, one isolate from the German collection of Microorganisms and Cell Cultures (DSMZ), and 21 sequences from GenBank were analyzed using MP and UPGMA. Both analyses showed that isolates fell into four well-delineated clades, namely G. adspersum, G. applanatum, G. resinaceum and G. lucidum. All the isolates collected from P. pinea were confirmed as G. adspersum. Previously, G. adspersum had been reported on hardwood trees and infrequently on a few conifers. Only sporocarps identified on the basis of morphological characters as G. applanatum have sporadically been recorded on P. pinea; there is no previous record of G. adspersum on this host. Somatic incompatibility tests showed that infections, probably via basidiospores, and symptoms apparently associated with wood colonization by G. adspersum, worsened during the 3-year course of the study

Ocorrência de tripes na cultura do lisianto em diferentes condições de cultivo protegido

Damages caused by thrips (Thysanoptera) are a constant concern in greenhouse. In lisianthus, Eustoma grandiflorum (Raf.) Shinners (Gentianaceae), it may cause direct and indirect damage. Thrips can affect flowers aesthetics through feeding on their petals. This study aimed to recording the thrips species associated with lisianthus under protected cultivation, assessing differences in species composition among lisianthus cultivars and among different growing conditions. The experiment was conducted in commercial greenhouses in the “Floricultura Florist” company, municipality of Dois Irmãos, RS state. The experiment was conducted from January to February 2013, comparing four cultivars with different colors (Marina, Orange Flash, Tu 668 and Ace White) and two greenhouses with structural differences. Each flower bed (25mx1m) containing one cultivar (treatment) was divided into 5 plots in which 10 plants were randomly selected and evaluated from the opening of the first floral bud until the cut of the flowers. The most common thrips species were Frankliniella schultzei and F. occidentalis. The different growing conditions influenced the amount and composition of thrips species collected. There was variation in the average number of thrips gathered from cultivated varieties. This paper presents the first record of thrips species on E. grandiflorum in greenhouse of Brazil.Os danos causados por tripes (Thysanoptera) são uma preocupação constante em cultivo protegido. Em lisianto, Eustoma grandiflorum (Raf.) Shinners (Gentianaceae), podem provocar danos diretos e indiretos, e prejudicar a estética das flores ao se alimentarem de suas pétalas. Este estudo objetivou registrar as espécies de tripes associadas ao lisianto sob cultivo protegido e avaliar diferenças na composição das espécies entre cultivares de lisianto e entre diferentes condições de cultivo. O experimento foi conduzido em cultivo comercial na empresa "Floricultura Florist", no município de Dois Irmãos-RS. As coletas ocorreram entre janeiro e fevereiro de 2013, em quatro cultivares com colorações distintas (Marina, Orange Flash, Tu 668 e Ace White) e em duas diferentes áreas de cultivos protegidos com distintas características estruturais. Foram realizadas amostragens semanais, durante o período de 24 de janeiro a 07 de fevereiro de 2013. Cada canteiro (25mx1m) contendo uma cultivar (tratamento) foi subdividido em 5 parcelas, nas quais 10 plantas foram sorteadas ao acaso e avaliadas desde a abertura dos botões até o corte das flores. As espécies de tripes mais frequentes foram Frankliniella schultzei e F. occidentalis. As diferentes condições de cultivo influenciaram na quantidade e na composição de espécies de tripes coletadas, e foi observada variação no número médio de tripes coletados entre as cultivares estudadas. Este artigo apresenta o primeiro registro de espécies de tripes em cultivo protegido de E. grandiflorum no Brasil

Strategies to optimize the use of marginal donors in liver transplantation.

Liver transplantation is the treatment of choice for end stage liver disease, but availability of liver grafts is still the main limitation to its wider use. Extended criteria donors (ECD) are considered not ideal for several reasons but their use has dramatically grown in the last decades in order to augment the donor liver pool. Due to improvement in surgical and medical strategies, results using grafts from these donors have become acceptable in terms of survival and complications; nevertheless a big debate still exists regarding their selection, discharge criteria and allocation policies. Many studies analyzed the use of these grafts from many points of view producing different or contradictory results so that accepted guidelines do not exist and the use of these grafts is still related to non-standardized policies changing from center to center. The aim of this review is to analyze every step of the donation-transplantation process emphasizing all those strategies, both clinical and experimental, that can optimize results using ECD