Learning What To Say And What To Do: A Model For Grounding Language And Actions

Automation is becoming increasingly important in nowadays society, with robots performing a lot of repetitive tasks in industry and even entering our households in the form of vacuum cleaners and lawn mowers. When considering regular tasks outside of the controlled environments of industry, robots tend to perform poorly. In particular, in situations where robots have to interact with humans, a problem arises: how can a robot understand what the human means? While a lot of work has been made in the past towards visual perception and classification of objects, but understanding what action a verb translates into has still been an unexplored area. In solving this challenge, we would enable robots to execute commands given in natural language, and also to verbalise what actions they are performing when prompted. This work studies how a robot can learn the meaning behind the sentences humans use, how it translates into its perception and the real world, but also how to translate its actions into sentences humans understand. To achieve this we propose a novel Bidirectional machine learning model, along with a data collection module that can be used by non-technical users. The main idea behind this model is the ability to generalise to novel concepts, being able to compose new sentences and actions from what it learned previously. Humans show this ability to generalise from a young age, and it is a desirable feature for this model. By using humans natural teaching instincts to teach the robot together with this generalisation ability we hope to obtain a model that allows people everywhere to teach the robot to perform the actions we desire. We validate the model in a number of tasks, using an iCub and Pepper robots physically interacting with objects in order to complete a natural language command. We test different actions, including motor actions and emotional displays, while using both transitive and intransitive verbs in the natural language commands. The main contribution of this thesis is the development of a Bidirectional Learning Algorithm, applied to a Multiple Timescale Recurrent Neural Network enabling these models to link action and language in a bidirectional way. A second contribution sees the extension of Multiple Timescale architectures to Long Short-Term Memory models, increasing the capabilities of these models. Finally the third contribution is in the form of data collection modules, with the development of an easy-to-use module based on physical interaction and speech to provide the iCub and Pepper robots with the data to be learned

Crescimento natural de nano-estruturas de captação de luz a partir de microalgas para soluções energéticas bioinspiradas

Dissertação de mestrado em Physics Engineering, Devices, Microsystems and NanotechnologiesLight, the most widely available source of energy, enables the development of devices that are under constant studying of optimization and improvement. Nowadays, due to the miniaturization of components, nanoscale technologies are at an all-time high. Photonic crystals, nanostructures characterized by defined periodic wavelength-scale patterns, e.g. pore lattices filled with a different refractive index than that of the bulk material, have the ability to ma nipulate light at ease. This periodicity induces a periodic dielectric function that gives rise to the so-called photonic bandgaps, a set of wavelengths/energies and crystallographic directions for which propagation within the photonic crystal is forbidden. Photonic crystals are commonly produced in cleanrooms involving precise nanofabrication techniques. The demand for a high reproducibility of such structures can, in a long term, become cost-unfriendly, not to mention the environmentally hazardous methods some techniques may require. Recent researches confirmed that natural photonic crystals exist in the silicon dioxide exosqueletons of diatoms, abundant microalgae that precipitate silicid acid from water. This Thesis focuses on the study of a specific part of those exosqueletons: the girdles. The highly ordered lattices these structures exhibit create photonic bandgaps with preserved and well defined photonic properties, paving the way for their utilization as environmentally friendly photonic materials. This Thesis shows, through theoretical and experimental studies, the preparation and modification of these photonic structures by tailoring the refractive index contrast with the deposition of higher refractive index materials, aiming to fine tuning of the photonic properties, thus presenting diatom biomass as a highly available photonic crystal with well preserved photonic properties. Potential applications are not restricted to devices that rely on light, but also involving sensing by colorimetry or refractive index change detection.Luz, a maior fonte de energia disponível, permite o desenvolvimento de dispositivos que se encontram sob estudo constante em termos de otimização e aprimoramento. Nos dias de hoje, devido à miniaturização de componentes, tecnologias à nano-escala têm se destacado cada vez mais. Cristais fotónicos, nano-estruturas caracterizadas por padrões periódicos definidos à escala do comprimento de onda, por exemplo redes de poros preenchidas com um índice de refração diferente do material que compõe a estrutura, são capazes de facilmente manipular a luz. Esta periodicidade induz uma função dielétrica periódica que dá origem aos hiatos fotónicos, um intervalo de comprimentos de onda/energias e direções cristalográficas nos quais a propagação de luz no cristal fotónico é proíbida. Cristais fotónicos são regularmente produzidos em ambiente de sala limpa envolvendo técnicas de nanofabricação precisas. A exigência de elevada reprodutibilidade de tais estruturas pode, a longo prazo, tornar-se um processo dispendioso, para não falar dos métodos perigosos para o ambiente que algumas técnicas possam requerir. Pesquisas recentes confirmaram a existência de cristais fotónicos naturais nos exoesqueletos de dióxido de silício de diatomáceas, microalgas abundantes que precipitam ácido silícico da água. Esta Tese foca-se no estudo de uma parte específica destes exoesqueletos: as girdles. As redes altamente ordenadas que estas estruturas exibem criam hiatos fotónicos com propriedades bem definidas e preservadas, abrindo caminho para a sua utilização como materiais fotónicos amigos do ambiente. Esta Tese demonstra, com recurso a estudos teóricos e experimentais, a preparação e modificação destas estruturas periódicas através da modulação do contraste de índice de refração com deposição de materiais de elevado índice de refração, com o objetivo de modificar as propriedades fotónicas, e assim apresentar a biomassa proveniente de diatomáceas como cristais fotónicos altamente disponíveis e com propriedades fotónicas altamente preservadas. As possíveis aplicações não se restringem apenas a dispositivos que trabalhem diretamente com luz, mas também envolvendo deteção por colorimetría a deteção de mudanças no índice de refração

Channel Selection Algorithms for Cognitive Radio Systems

The Spectrum of Radio Frequency plays a key/central role in supporting the operation of the whole range of mobile wireless devices. Such centrality derives from the fact it is necessary when operating different technologies, such as TV, cellular networks, and satellite transmissions, among others. Hence, the urgent need to design a better management of these technologies as a means of minimizing the amount spectrum that is used. This study was developed in two different stages. During a preliminary stage we came up with a modelling method of the service time duration in cognitive radio networks, which fosters a better management of the spectrum through its opportunistic use. In a second stage, we propose four algorithms to manage these cognitive radio networks, using the modelling method that was defined in the first stage, as a basis. After implementing all the simulations, it was possible to verify the feasibility of this modelling methodology and also to confirm the expected results. It should also be pointed out that the four suggested algorithms were tested by carrying out simulations, being effective solutions for difference operational scenarios

VR serious game to treat schizophrenia

The present work aims to optimize and produce scenarios of a serious game, and improve its immersiveness, enabling the capture of feedbacks, by configuring sensors that can monitor the user of the application for changes in the game in real time, making it possible to have better control over the player’s experience. With this, progressing research into the improvements of virtual reality when applied to the treatment of people with schizophrenia.info:eu-repo/semantics/publishedVersio

Virtual reality haptic device for mental Illness treatment

Schizophrenia is a mental disorder that alters mental functioning and can cause hallucinations, mental disorientation, and a variety of other symptoms, which results in a separation of schizophrenics from society. Despite the fact that the condition has been known about for a long time, there is still an urgent need for research and testing to develop better therapies. Virtual reality (VR) has had interesting outcomes when used to treat illnesses, and it is gradually emerging as a viable technical choice for the healthcare sector due to its immersion, which offers better and more intense user experiences. Once linked to a serious game, it can introduce the user to a number of situations that, when combined with medical assistance, aid in their rehabilitation and treatment. The use of haptic devices enhances VR immersion by enabling users to comprehend virtual environments with greater nuance, which increases their level of believing in the new environment they are in. When used in conjunction with VR, it can improve the efficacy of the treatment, making its use viable for the treatment of psychic diseases. The goal of this research is to develop haptic vest interactions using a three-dimensional virtual testing scenario to support and improve the use of VR for rehabilitation and therapy for schizophrenia. The established functionalities can be applied to a further serious game with the same focus.info:eu-repo/semantics/publishedVersio

A Portuguese Study

A balanced implementation of functionalities within a commercial internet presence is important, because of not only the involved complexity and cognitive load required in their use, but also for financial reasons. Investing money on features (e.g., software modules, programming time, maintenance and update, etc.) that are not valued by online consumers, hinders an efficient allocation of resources, especially when financial resources are scarce, a situation that corresponds too many small businesses operating on the internet. However, literature provides little help for managers to decide which functionalities should be implemented, according to a rational basis. Within this context, this research sought to fill in the gap between literature review and the need for helping companies to understand better how to build and keep online businesses. The authors work identified 16 essential functionalities grouped into four sets: order processing, advertising and prominence, product analysis, and payment.info:eu-repo/semantics/publishedVersio

Monitoring biotransformations in polyesters

This paper describes two methods to monitor esterase hydrolysis at the surface of polyester fibres (PET-Polyethylene terephthalate). The hydroxyl groups were determined on the fibre surface by alkaline reaction with a reactive dye (CI Reactive Black 5) and colour intensity was determined using a reflectance spectrophotometer. The terephthalic acid solution formed was also quantified after reaction with peroxide by fluorimetric determination of the resulting hydroxyterephthalic acid. Detailed descriptions of those methods are given in this paper

Experiments with IPV6 network mobility using nemo protocol

The NEMO (NEtwork MObility) protocol, as normalized by IETF, allows a transparent movement of a whole IPv6 network. This mobile network can thus attach to different points in the Internet without losing TCP/IP connectivity of its mobile nodes. In this paper we briefly describe the NEMO protocol and present a simple architecture deployed to test its main functionalities. We also discuss the results obtained thus far with the use of popular TCP and UDP applications in a mobile environment: video streaming transfer, remote access using SSH and FTP file transfer

Boas práticas em projectos nacionais de parceria sobre igualdade de género

Comunicação apresentada no 5º Congresso Nacional de Administração Pública, em Lisboa de 29 a 30 de Outubro de 2007