Optimisation of Bluetooth wireless personal area networks

In recent years there has been a marked growth in the use of wireless cellular telephones, PCs and the Internet. This proliferation of information technology has hastened the advent of wireless networks which aim to increase the accessibility and reach of communications devices. Ambient Intelligence (Ami) is a vision of the future of computing in which all kinds of everyday objects will contain intelligence. To be effective, Ami requires Ubiquitous Computing and Communication, the latter being enabled by wireless networking. The IEEE's 802.11 task group has developed a series of radio based replacements for the familiar wired ethernet LAN. At the same time another IEEE standards task group, 802.15, together with a number of industry consortia, has introduced a new level of wireless networking based upon short range, ad-hoc connections. Currently, the most significant of these new Wireless Personal Area Network (WPAN) standards is Bluetooth, one of the first of the enabling technologies of Ami to be commercially available. Bluetooth operates in the internationally unlicensed Industrial, Scientific and Medical (ISM) band at 2.4 GHz. unfortunately, this spectrum is particularly crowded. It is also used by: WiFi (IEEE 802.11); a new WPAN standard called Zig- Bee; many types of simple devices such as garage door openers; and is polluted by unintentional radiators. The success of a radio specification for ubiquitous wireless communications is, therefore, dependant upon a robust tolerance to high levels of electromagnetic noise. This thesis addresses the optimisation of low power WPANs in this context, with particular reference to the physical layer radio specification of the Bluetooth system

Quantifying the sense of presence in virtual reality using physiological data

Les mesures fisiològiques de l'experiència de joc (PX) durant el joc han anat incrementant en popularitat en les comunitats de recerca sobre jocs. La sensació de presència, que es refereix a la impressió psicològica d'estar en un entorn virtual, és vista com un factor principal influent en el PX. Aquesta tesi explora com les mesures fisiològiques hi estan relacionades mentre es juga a un joc de rol de realitat virtual (VR). En trobem una correlació negativa significativa amb la temperatura de la pell, la qual interpretem com a relacionada amb que la manca de confort tèrmic estigui associada amb nivells menors de sensació de presència. Un dispositiu wearable no invasiu comunament utilitzat per a mesures fisiológiques és la pulsera E4 d'Empatica, que ofereix múltiples mesures fisiològiques incloent l'activitat electrodèrmica, la freqüència cardíaca i la temperatura de la pell. Tanmateix, la integració de l'E4 amb motors de joc populars com Unity resulta difícil a causa d'obstacles com errors de programari crítics gens evidents a la llibreria i la limitada aplicabilitat de la documentació en el context de Unity. Així doncs presentem E4UnityIntegration-MIT, un plugin de Unity de codi obert dissenyat per a mitigar els reptes associats amb integrar l'E4 a projectes de Unity. El plugin exposa l'API de l'E4 permetent-ne la interacció amb scripts C# de Unity, habilitant així el recull i seguiment de dades en temps real, i proveeix la funcionalitat de guardar-les en un fitxer extern per permetre'n l'anàlisi. L'estudi presentat, que va dependre de E4UnityIntegration-MIT, alhora en serveix de validació.Las medidas fisiológicas de la experiencia de juego (PX) durante el juego han ido incrementando en popularidad en los círculos de investigación de juegos. La sensación de presencia, que se refiere a la impresión psicológica de estar en un entorno virtual, es vista como un factor principal influyente en el PX. Esta tesis explora como las medidas fisiológicas estan relacionadas con ella mientras se juega a un juego de rol de realidad virtual (VR). Hallamos una correlación negativa significativa con la temperatura de la piel, la cual interpretamos como relacionada con que el disconfort térmico esté asociado con niveles menores de sensación de presencia. Un dispositivo wearable comúnmente usado para medidas fisiológicas es la pulsera E4 de Empatica, que ofrece múltiples medidas fisiológicas incluyendo la actividad electrodérmica, la frecuencia cardíaca y la temperatura de la piel. Sin embargo, la integración del E4 con motores de juego populares como Unity resulta difícil a causa de obstáculos como errores de software críticos nada obvios en la librería y la limitada aplicabilidad de su documentación en el contexto de Unity. Así pues presentamos E4UnityIntegration-MIT, un plugin de Unity de código abierto diseñado para mitigar los retos asociados con integrar el E4 en proyectos de Unity. El plugin expone la API del E4 permitiendo su interacción con scripts de C# de Unity, habilitando así la recolección y el seguimiento de los datos en tiempo real, y provee la funcionalidad de guardarlos en un fichero externo para permitir su análisis. El estudio presentado, que dependió de E4UnityIntegration-MIT, sirve al mismo tiempo como su validación.Physiological measurement of player experience (PX) during gameplay has been of increasing interest within game research circles. Sense of presence, which refers to players’ psychological feeling of being in a virtual environment, is seen as a major factor influencing PX. This thesis work explores how physiological measurements relate to sense of presence while playing a virtual reality (VR) roleplaying game. We find a significant negative correlation with skin temperature, which we interpret as having to do with thermal discomfort being associated with lower levels of sense of presence in VR. A commonly-used non-invasive wearable device for physiological measurement is the Empatica E4 wristband, which offers multiple physiological metrics including electrodermal activity, heart rate and skin temperature. That said, the E4’s integration with popular game engines such as Unity proves difficult due to obstacles such as non-obvious critical bugs in the library and limited documentation applicability within the Unity context. We thus present E4UnityIntegration-MIT, an open-source Unity plugin designed to mitigate the challenges associated with integrating the E4 into Unity projects. The plugin exposes the E4’s API for interfacing with Unity C# scripts, thereby enabling realtime data collection and monitoring, and provides the affordance of saving the data in an external file for data analysis purposes. The study here presented, which relied on E4UnityIntegration-MIT, also serves as a validation study for the plugin.Outgoin

A Wizard Hat for the Brain: Predicting Long-Term Memory Retention Using Electroencephalography

Learning is a ubiquitous process that transforms novel information and events into stored memory representations that can later be accessed. As a learner acquires new information, any feature of a memory that is shared with other memories may produce some level of retrieval- competition, making accurate recall more difficult. One of the most effective ways to reduce this competition and create distinct representations for potentially confusable memories is to practice retrieving all of the information through self-testing with feedback. As a person tests themself, competition between easily-confusable memories (e.g. memories that share similar visual or semantic features) decreases and memory representations for unique items are made more distinct. Using a portable, consumer-grade electroencephalography (EEG) device, I attempted to harness competition levels in the brain by training a machine learning classifier to predict long- term retention of novel associations. Specifically, I compare the accuracy of two logistic regression classifiers: one trained using existing category-word pairings (as has been done previously in the literature), and one trained using new episodic image-name associations developed to more closely model memory competition. I predicted that the newly developed classifier would be able to more accurately predict long-term retention. Further refinements to the predictive model and its applications are discussed

Security and Privacy for IoT Ecosystems

Smart devices have become an integral part of our everyday life. In contrast to smartphones and laptops, Internet of Things (IoT) devices are typically managed by the vendor. They allow little or no user-driven customization. Users need to use and trust IoT devices as they are, including the ecosystems involved in the processing and sharing of personal data. Ensuring that an IoT device does not leak private data is imperative. This thesis analyzes security practices in popular IoT ecosystems across several price segments. Our results show a gap between real-world implementations and state-of-the-art security measures. The process of responsible disclosure with the vendors revealed further practical challenges. Do they want to support backward compatibility with the same app and infrastructure over multiple IoT device generations? To which extent can they trust their supply chains in rolling out keys? Mature vendors have a budget for security and are aware of its demands. Despite this goodwill, developers sometimes fail at securing the concrete implementations in those complex ecosystems. Our analysis of real-world products reveals the actual efforts made by vendors to secure their products. Our responsible disclosure processes and publications of design recommendations not only increase security in existing products but also help connected ecosystem manufacturers to develop secure products. Moreover, we enable users to take control of their connected devices with firmware binary patching. If a vendor decides to no longer offer cloud services, bootstrapping a vendor-independent ecosystem is the only way to revive bricked devices. Binary patching is not only useful in the IoT context but also opens up these devices as research platforms. We are the first to publish tools for Bluetooth firmware and lower-layer analysis and uncover a security issue in Broadcom chips affecting hundreds of millions of devices manufactured by Apple, Samsung, Google, and more. Although we informed Broadcom and customers of their technologies of the weaknesses identified, some of these devices no longer receive official updates. For these, our binary patching framework is capable of building vendor-independent patches and retrofit security. Connected device vendors depend on standards; they rarely implement lower-layer communication schemes from scratch. Standards enable communication between devices of different vendors, which is crucial in many IoT setups. Secure standards help making products secure by design and, thus, need to be analyzed as early as possible. One possibility to integrate security into a lower-layer standard is Physical-Layer Security (PLS). PLS establishes security on the Physical Layer (PHY) of wireless transmissions. With new wireless technologies emerging, physical properties change. We analyze how suitable PLS techniques are in the domain of mmWave and Visible Light Communication (VLC). Despite VLC being commonly believed to be very secure due to its limited range, we show that using VLC instead for PLS is less secure than using it with Radio Frequency (RF) communication. The work in this thesis is applied to mature products as well as upcoming standards. We consider security for the whole product life cycle to make connected devices and IoT ecosystems more secure in the long term

Assessing brain activations associated with emotional regulation during virtual reality mood induction procedures

Emotional regulation strategies are used by people to influence their emotional responses to external or internal emotional stimuli. The aim of this study is to evaluate the brain activations that are associated with the application of two different emotional regulation strategies (cognitive reappraisal and expressive suppression) during virtual reality mood induction procedures. We used Emotiv EPOC to measure the brain electrical activity of participants while sadness is induced using a virtual reality environment. We monitored 24 participants, who were distributed among three experimental groups: a control group, a cognitive reappraisal group and an expressive suppression group. In the control group, we found significant activations in several right frontal regions that are related to the induction of negative emotions . We also found significant activations in the limbic, occipital, and parietal regions in the emotional regulation groups. These regions are related to the application of emotional regulation strategies. The results are consistent with those shown in the literature, which were obtained through clinical neuroimaging systems.The work of A. Rodriguez was funded by the Spanish MEC under an FPI Grant BES-2011-043316. The work of Miriam Clemente was funded by the Generalitat Valenciana under a VALi+d Grant.Rodríguez Ortega, A.; Rey, B.; Clemente Bellido, M.; Wrzesien, M.; Alcañiz Raya, ML. (2015). Assessing brain activations associated with emotional regulation during virtual reality mood induction procedures. Expert Systems with Applications. 42(3):1699-1709. https://doi.org/10.1016/j.eswa.2014.10.006S1699170942