Adiabatic Computation - A Toy Model

We discuss a toy model for adiabatic quantum computation which displays some phenomenological properties expected in more realistic implementations. This model has two free parameters: the adiabatic evolution parameter $s$ and the $\alpha$ parameter which emulates many-variables constrains in the classical computational problem. The proposed model presents, in the $s-\alpha$ plane, a line of first order quantum phase transition that ends at a second order point. The relation between computation complexity and the occurrence of quantum phase transitions is discussed. We analyze the behavior of the ground and first excited states near the quantum phase transition, the gap and the entanglement content of the ground state.Comment: 7 pages, 8 figure

Dynamical properties across a quantum phase transition in the Lipkin-Meshkov-Glick model

It is of high interest, in the context of Adiabatic Quantum Computation, to better understand the complex dynamics of a quantum system subject to a time-dependent Hamiltonian, when driven across a quantum phase transition. We present here such a study in the Lipkin-Meshkov-Glick (LMG) model with one variable parameter. We first display numerical results on the dynamical evolution across the LMG quantum phase transition, which clearly shows a pronounced effect of the spectral avoided level crossings. We then derive a phenomenological (classical) transition model, which already shows some closeness to the numerical results. Finally, we show how a simplified quantum transition model can be built which strongly improve the classical approach, and shed light on the physical processes involved in the whole LMG quantum evolution. From our results, we argue that the commonly used description in term of Landau-Zener transitions is not appropriate for our model.Comment: 7 pages, 5 figures; corrected reference

Fast computational processing for mobile robots' self-localization

This paper intends to present a different approach to solve the Self-Localization problem regarding a RoboCup’s Middle Size League game, developed by MINHO team researchers. The method uses white field markings as key points, to compute the position with least error, creating an error-based graphic where the minimum corresponds to the real position, that are computed by comparing the key (line) points with a precomputed set of values for each position. This approach allows a very fast local and global localization calculation, allowing the global localization to be used more often, while driving the estimate to its real value. Differently from the majority of other teams in this league, it was important to come up with a new and improved method to solve the traditional slow Self-Localization problem.This work was developed at the Laboratório de Automação e Robótica by MINHO team´s researching and developing team, at University of Minho, under the supervision of Professor A. Fernando Ribeiro and A. Gil Lopes. The knowledge exchanging between the RoboCup’s MSL teams and community contributed greatly for the development of this work. This work has been supported by COMPETE: POCI-01- 0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Motion control of mobile autonomous robots using non-linear dynamical systems approach

This paper presents a solution to the problem of motion control of an autonomous robot, moving in a dynamical and unstable environment. It is based on non-linear dynamical systems, modelling the state variables that define the motion of a robot under an omnidirectional platform, like its direction of navigation and velocity. The approach used, is based on a set of non-linear differential equations that model the evolution of state variables along time, based on the concept of attractors and repellers. In the official RoboCup Middle Size League field, a target is used to attract the robot to a certain position (could be the ball or a desired position to receive the ball), while a repeller could move the robot away from its original path (given by obstacles in the surrounding environment). The research was firstly carried out in a computational simulation environment and later on with robots in a real environmentThis work was developed at the Automation and Robotics Laboratory by MINHO R&D TEAM, University of Minho, under the supervision of Professor A. Fernando Ribeiro and A. Gil Lopes. The knowledge exchanging between the RoboCup’s MSL teams and community contributed greatly for the development of this work. This work has been supported by COMPETE: POCI-01-0145-FEDER-007043 and FCT – Fundação para a Ciência e Tecnologia within the Project Scope: UID/CEC/00319/2013.info:eu-repo/semantics/publishedVersio

Reuse of effluent from dyeing process of polyamide fibers modified by double barrier discharge (DBD) plasma

Published online: 27 Feb 2015Low-temperature plasma technology becomes more and more attractive compared with traditional wet processes in textile preparation and finishing due to its high efficiency and low environmental impact. The objective of this study was to investigate the influence of dielectric barrier discharge plasma treatment on the trichromic dyeing process of polyamide 6.6 (PA66) and the reuse of the generated effluents for new dyeing processes. Chemical and physical characterization of the plasma-treated polyamide fibers was studied by means of static and dynamic contact angle, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy micrographs, and atomic force microscopy (AFM). Plasma treatment greatly increases the hydrophilicity and adhesion of PA66, due to the increase of polar groups and roughness on the fibers surface as confirmed by XPS and AFM. The kinetics of dyeing is quicker but leveled with high rubbing, light, and washing fastness quality. The reuse of the effluent obtained after dyeing of the plasma-treated fabrics showed excellent results of reproducibility, uniformity, and washing fastness. It was possible to reproduce the standard color for three dyeing cycles using the same effluent reducing the effluent load with a significant diminution in costs and environmental impact.Andrea Zille (C2011- UMINHO-2C2T-01) acknowledges funding from Programa Compromisso para a Ciencia 2008, Portugal

Development of Prometeu autonomous robot for ball handling in Eurobot

Eurobot is a robotics European challenge for the young generation (university and technical schools) which is held annually, with a different challenge in every edition, and participate around about 200 teams every year. Each game comprises two teams competing against each other and does not allow draws. This work describes the design, development and building up of an autonomous mobile robot to fulfill this challenge. This paper includes the challenge description, robot design, sensors used, the strategy used and some conclusion. The team that built this robot and participated on Eurobot is made up of 4 industrial electronic undergraduate students from University of Minho

Optimization of fast moving robots and implementation of I2C protocol to control electronic devices

This paper briefly describes the main changes in the robots from Minho Team since the last RoboCup. Work has been carried out on the robots in order to constantly improve their capabilities, based on the experiences from previous participations. The main topics to deal in this paper are related with the I2C new communications protocol recently implemented in the robots, a description of the whole electronics system based on a new diagram which contains all the devices used in the robots, the inclusion of new faster motors, a description of the robot game play strategy, some operating system remarks which are related to some requirements of our actual system, and the main conclusions related to the work carried out so far. The use of the I2C protocol forced the team to change all the electronic boards and these were completely redesigned in-house, tested and implemented on the robots.Fundação para a Ciência e a Tecnologia (FCT) - POSI/ROBO/43892/200