Development of a software platform to control squads of unmanned vehicles in real-time

This paper proposes a new software platform to control and monitor a squad of unmanned vehicles. Through the use of an open-source flight controller and an on-board Raspberry Pi it is possible to create a system that enables communication between a remote ground control stations (GCS) and a unmanned aerial vehicles (UAVs). Both are connected through the use of wireless and cellular networks like Wi-Fi, 3G and 4G which have the required support to allow for communication beyond line of sight

Using distance sensors to perform collision avoidance maneuvres on UAV applications

The Unmanned Aerial Vehicles (UAV) and its applications are growing for both civilian and military purposes. The operability of an UAV proved that some tasks and operations can be done easily and at a good cost-efficiency ratio. Nowadays, an UAV can perform autonomous missions. It is very useful to certain UAV applications, such as meteorology, vigilance systems, agriculture, environment mapping and search and rescue operations. One of the biggest problems that an UAV faces is the possibility of collision with other objects in the flight area. To avoid this, an algorithm was developed and implemented in order to prevent UAV collision with other objects. “Sense and Avoid” algorithm was developed as a system for UAVs to avoid objects in collision course. This algorithm uses a Light Detection and Ranging (LiDAR), to detect objects facing the UAV in mid-flights. This light sensor is connected to an on-board hardware, Pixhawk’s flight controller, which interfaces its communications with another hardware: Raspberry Pi. Communications between Ground Control Station and UAV are made via Wi-Fi or cellular third or fourth generation (3G/4G). Some tests were made in order to evaluate the “Sense and Avoid” algorithm’s overall performance. These tests were done in two different environments: A 3D simulated environment and a real outdoor environment. Both modes worked successfully on a simulated 3D environment, and “Brake” mode on a real outdoor, proving its concepts.info:eu-repo/semantics/publishedVersio

Disordered two-dimensional superconductors: roles of temperature and interaction strength

We have considered the half-filled disordered attractive Hubbard model on a square lattice, in which the on-site attraction is switched off on a fraction $f$ of sites, while keeping a finite $U$ on the remaining ones. Through Quantum Monte Carlo (QMC) simulations for several values of $f$ and $U$, and for system sizes ranging from $8\times 8$ to $16\times 16$, we have calculated the configurational averages of the equal-time pair structure factor $P_s$, and, for a more restricted set of variables, the helicity modulus, $\rho_s$, as functions of temperature. Two finite-size scaling {\it ansatze} for $P_s$ have been used, one for zero-temperature and the other for finite temperatures. We have found that the system sustains superconductivity in the ground state up to a critical impurity concentration, $f_c$, which increases with $U$, at least up to U=4 (in units of the hopping energy). Also, the normalized zero-temperature gap as a function of $f$ shows a maximum near $f\sim 0.07$, for $2\lesssim U\lesssim 6$. Analyses of the helicity modulus and of the pair structure factor led to the determination of the critical temperature as a function of $f$, for $U=3,$ 4 and 6: they also show maxima near $f\sim 0.07$, with the highest $T_c$ increasing with $U$ in this range. We argue that, overall, the observed behavior results from both the breakdown of CDW-superconductivity degeneracy and the fact that free sites tend to "push" electrons towards attractive sites, the latter effect being more drastic at weak couplings.Comment: 9 two-column pages, 14 figures, RevTe

Sistemas de informações estratégicas para a vitalidade da empresa

Para assegurar a sua existência, a empresa carece de informação crítica - informação de conteúdo específico, disponibilizada no bom momento, adaptada ao utilizador, devidamente contextualizada de forma a explicitar as ligações essenciais das mutações comportamentais dos indivíduos com os acontecimentos e com as tecnologias. As fontes de informações formais e informais não são neutras, constata-se que elas, em geral, tratam a informação não para atender necessariamente às questões do utilizador ou suas demandas, mas, segundo os objetivos daqueles que as geram e para desempenhar o papel que lhes foi confiado. Colocar em relação demanda e oferta de informação requer o concurso de profissionais preparados para aceitar o risco de uma integração forte e intensa entre esses dois espaços de valores