2016
Autores
Silva, MP; Goncalves, J; Costa, P;
Publicação
EDULEARN16: 8TH INTERNATIONAL CONFERENCE ON EDUCATION AND NEW LEARNING TECHNOLOGIES
Abstract
In this paper an analysis of MicroFactory is carried out and its potential for generating a diversified set of didactic experiences is evaluated. MicroFactory is a robotic competition based on a previously existing competition called Robot@Factory. Robot@Factory is a Portuguese robotic competition whose first edition was held in 2011 in Lisbon. The scenario of the competition simulates a factory which has two warehouses, and eight processing machines. The flow of the materials inside the factory starts at the Incoming Warehouse and ends at the Outgoing Warehouse, eventually passing through one or more processing machines. The robots must collect, transport and position the materials along the process, having to self-localize and navigate while avoiding collisions with walls, obstacles and other robots. There is the option of following predefined tracks present on the floor to ease the navigation problem. Robot@Factory poses challenges like dynamic task scheduling, robot cooperation, trajectory planning, robot navigation with obstacle avoidance, robot self-localization and materials identification and manipulation. Related research contributes to improve AGVs (Automated Guided Vehicle systems) technology. Presently this competition is integrated in Festival Nacional de Robotica, a yearly event which attracts lots of public, contributing also to STEM (Science, Technology, Engineering and Mathematics) popularization. MicroFactory was conceived to be low-cost and easily implementable in a small space, be it a classroom or the school robotics club. The ground area of the factory scenario was reduced to approximately one ninth of its original value. The scenario materials were simplified -the floor is now an A0 printed sheet and the warehouses and machines dimensions are so that they can be 3D printed or made out of LEGO (TM) bricks; both machines and parts had active elements with LEDs and now they are passive. Besides the competition scenario it was also conceived a prototype robot for the competition. It's a 3D printed robot, based on an Arduino board and accessible electronic parts. The creation of this competition is part of a wider Open Source project, aiming to develop project-based collaborative didactic experiences involving robotics and low-cost 3D printed educational robots based on generic electronics to support those experiences. Currently efforts are being dedicated to the inclusion of more sensors in the competition robot, namely low-cost distance sensors and a weight sensor at the claws, the inclusion of different kinds of motors, the development of a new version of the robot incorporating a Raspberry Pi board, the development of a very precise robot localization system, and the conception of a diversified set of didactic experiences based on the MicroFactory competition. This article presents an analysis of MicroFactory and of its inherent challenges. Through this analysis it will be possible to identify topics that can be taught and learned while developing robots to participate in the competition, and to collect elements that will be very useful in the planning and implementation of didactic experiences that work those topics.
2016
Autores
Mendes, D; Relvas, F; Ferreira, A; Jorge, J;
Publicação
22ND ACM CONFERENCE ON VIRTUAL REALITY SOFTWARE AND TECHNOLOGY (VRST 2016)
Abstract
Object manipulation is a key feature in almost every virtual environment. However, it is difficult to accurately place an object in immersive virtual environments using mid-air gestures that mimic interactions in the physical world, although being a direct and natural approach. Previous research studied mouse and touch based interfaces concluding that separation of degrees-of-freedom (DOF) led to improved results. In this paper, we present the first user evaluation to assess the impact of explicit 6 DOF separation in mid-air manipulation tasks. We implemented a technique based on familiar virtual widgets that allow single DOF control, and compared it against a direct approach and PRISM, which dynamically adjusts the ratio between hand and object motions. Our results suggest that full DOF separation benefits precision in spatial manipulations, at the cost of additional time for complex tasks. From our results we draw guidelines for 3D object manipulation in mid-air.
2016
Autores
Derogarian, F; Ferreira, JC; Tavares, VG;
Publicação
INTERNATIONAL JOURNAL OF CIRCUIT THEORY AND APPLICATIONS
Abstract
This paper proposes a new open-loop and low complexity (small size) fast-lock synchronization circuit for clock and data recovery in wearable systems. The system includes sensors embedded in textile and connected by conductive yarns. Synchronization is based on the open-loop selection of the correct phase of the receiver clock synchronously with the incoming signal. The clock generator of the receiver is an autonomous oscillator set to operate at the same nominal frequency. The circuit lock time is at most one clock cycle, faster than all methods based on phase-locked loops or delay-locked loops. The circuit can be used for baseband communication independently of the signal coding method used in the physical layer, making it suitable for many applications. The fully digital circuit (including non-return-to-zero inverted decoder) occupies 0.0022 in a 0.35 complementary metal-oxide semiconductor (CMOS) process, a smaller implementation than many existing circuits, and supports a maximum system clock frequency of 70 for a 35-data rate. Experimental results demonstrate that the proposed circuit robustly generates a synchronous clock for data recovery. The circuit is suitable for systems that tolerate some jitter but requires fast lock time, small size, and low energy consumption. Copyright (c) 2015 John Wiley & Sons, Ltd.
2016
Autores
Magalhães, SMC; Leal, VMS; Horta, IM;
Publicação
Energy and Buildings
Abstract
Empirical data for residential indoor temperature and its determinants have important implications for policymakers in terms of the assessment of thermal comfort, health of occupants and the use for supporting energy demand models. With the purpose of advancing this knowledge, the indoor temperatures of 141 households in the Northern Portugal were measured at a half-hourly basis during the winter of 2013-2014. The observed mean winter daily indoor temperature at the occupied period was 14.9 °C for the bedrooms and 16.6°C for the living rooms. The results show that indoor temperatures are significantly below the comfort levels generally accepted, which could be an indication of future potential rebound effects. Results also reinforce the idea that 'cold homes' during winter season are a reality even in the southern European countries. Models for predicting the daily mean bedroom and living room temperature were developed using an enhanced linear regression with panel-corrected standard errors. The results showed that climatic conditions, and especially building characteristics, affect significantly the bedroom and living room's indoor temperatures.
2016
Autores
Paiva, JS; Rodrigues, S; Silva Cunha, JPS;
Publicação
2016 38TH ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)
Abstract
Firefighting is a stressful occupation. The monitoring of psychophysiological measures in those professionals can be a way to prevent and early detect cardiac diseases and other stress-related problems. The current study aimed to assess morphological changes in the ECG signal induced by acute stress. A laboratory protocol was conducted among 6 firefighters, including a laboratory stress-inducer task - the Trier Social Stress Task (TSST) - and a 2-choice reaction time task (CRTT) that was performed before (CRTT1) and after (CRTT2) the stress condition. ECG signals were continuously acquired using the VitalJacket (R), a wearable t-shirt that acts as a medical certified ECG monitor. Results showed that ECG morphological features such as QT and ST intervals are able to differentiate stressful from non stressful events in first responders. Group mean Visual Analogue Scale (VAS) for stress assessment significantly increased after the stress task (TSST), relatively to the end of CRTT2 (after TSST: 4.67 +/- 1.63; after CRTT2: 3.17 +/- 0.75), a change that was accompanied by a significant increase in group mean QT and ST segments corrected for heart rate during TSST. These encouraging results will be followed by larger studies in order to explore those measures and its physiological impact under realistic environments in a higher scalability.
2016
Autores
Proença, J; Clarke, D;
Publicação
FORMAL ASPECTS OF COMPONENT SOFTWARE
Abstract
Typed models of connector/component composition specify interfaces describing ports of components and connectors. Typing ensures that these ports are plugged together appropriately, so that data can flow out of each output port and into an input port. These interfaces typically consider the direction of data flow and the type of values flowing. Components, connectors, and systems are often parameterised in such a way that the parameters affect the interfaces. Typing such connector families is challenging. This paper takes a first step towards addressing this problem by presenting a calculus of connector families with integer and boolean parameters. The calculus is based on monoidal categories, with a dependent type system that describes the parameterised interfaces of these connectors. As an example, we demonstrate how to define n-ary Reo connectors in the calculus. The paper focusses on the structure of connectors-well-connectedness-and less on their behaviour, making it easily applicable to a wide range of coordination and component-based models. A type-checking algorithm based on constraints is used to analyse connector families, supported by a proof-of-concept implementation.
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