Dissertations / Theses on the topic 'Sensors'

Nous sensors electroquímics per a analisis decentralitzats és una tesis que emmarca diferents aspectes del desenvolupament de sensors potenciomètrics, des de la seva fabricació, el diseny adequat, i finalment, la seva aplicabilitat en escenaris reals. En el context actual, l'evolució de la tecnologia, especialment l'aparició a nivell global d'internet, i la disponibilitat d'aquesta a baix cost han permès la creació d'eines que ens permeten connectar el món físic i, en el cas d'aquesta tesis, el món químic a la xarxa. Aquesta connexió aporta un nou grau dins l'escala de valor per a la societat actual. Concretament, aquesta aportació tecnològica va adreçada a superar els nous reptes de l'actualitat, com poden ser la sostenibilitat del sistema sanitari a causa de l'embelliment de la societat, el control medioambiental, així com també mantenir la seguretat per a la societat del benestar del futur. Així doncs, aquesta tesis presenta solucions efectives per al desenvolupament d'eines de captació d'informació que serviràn per nudrir a la societat de major coneixement. Conseqüentment, produint nous negocis al voltant, de la fabricació, processament i creació de valor entorn a aquestes dades. La recerca i desenvolupament de sensors potenciomètrics integrats a la roba per detectar els nivells d'electròlits i sensors senzills de paper per a la determinació de biomolècules, com la glucosa, són alguns dels objectius aconseguits en aquesta tesis. A més a més, sensors integrats en globus permeten l'estudi de les seves propietats mecàniques i electroquímiques, així com també, aporten noves solucions a problemes reals. Totes aquestes aplicacions serveixen de portals de captació d'informació química cap a la integració dins la nova societat de la informació.
Nuevos sensores electroquímicos para analisis decentralizados es una tesis que enmarca diferentes aspectos del desarrollo de sensores potenciométricos, desde su fabricación, el diseño adecuado, i finalmente, su aplicabilidad en escenarios reales. En el contexto actual, la evolución de la tecnología, especialmente la aparición a nivel global de internet, y la disponibilidad de esta a bajo coste han permitido la creación de herramientas que nos permiten conectar el mundo físico y, en el caso de esta tesis, el mundo químico a la red. Esta conexión aporta un nuevo grado dentro la escala de valor para la sociedad actual. Concretamente, esta aportación tecnológica va dirigida a superar los nuevos retos de la actualidad, como pueden ser la sostenibilidad del sistema sanitario a causa del envejecimiento de la poblacion, el control medioambiental, así como también mantener la seguridad para la sociedad del bienestar del futuro. Entonces, esta tesis presenta soluciones efectivas para el desarrollo de herramientas de captación de información que servirán para nutrir a la sociedad de un mayor conocimiento. Por consiguiente, produciendo nuevos negocios alrededor, de la fabricación, procesado i creación de valor en los datos obtenidos. La investigación y desarrollo de sensores potenciométricos integrados en la ropa para detectar los niveles de electrolitos y sensores simples en papel para la determinación de biomoléculas, como la glucosa, son algunos de los objetivos conseguidos en esta tesis. Además, sensores integrados en globos permiten el estudio de sus propiedades mecánicas y electroquímicas, así como, aportando nuevas soluciones a problemas reales. Todas estas aplicaciones sirven de portales de captación de información química hacia la integración dentro de la nueva sociedad de la información.
ew Electrochemical Sensors for Decentralized Analysis is a thesis that wisely discuss the developments of potentiometric sensors, from the fabrication step, the use of a suitable design, to the applicability in real scenarios. Nowadays, the evolution of technology, specially the creation of the global internet network, and the low-cost availability of such technology have allowed the development of tools that connect the physical world and, addressed in this thesis, the chemical world into the network. This connection adds a new level in the value chain for the present society. Precisely, this technology approach is focus on circumvent new present challenges of society. For instance, sustainability of the healthcare system caused by the population aging, environmental monitoring, as well as, keep security and safety to the welfare of society of the future. Therefore, this thesis presents successful solutions for the development of tools to gather chemical information. This information will nurture society with high-value knowledge. Accordingly, new business development from, sensing products, data treatment and information management are going to be created. Research and development of potentiometric sensors integrated into garments for electrolyte detection and simple sensors built in paper for biomolecules determination, such as glucose, and liquid monitoring, such as sweat, are some of the accomplished objectives from this thesis. Furthermore, balloon-embedded sensors allow the study of the mechanical and electrochemical properties of the electrodes, as well as, contributing with new solutions to real problems. All the applications developed in this thesis are utilized as gateways for chemical information acquisition towards the integration into the new information society.

In recent years wireless sensor network (WSN) is introduced in the fresh food tracking area as a promising solution to monitor the food transportation process. The widely applications of WSN are demanding a Universal Sensor Interface (USI) that is able to support large numbers of sensors, including gas sensors, force sensors, temperature sensors, water quality sensors, etc. In this thesis, the Universal Sensor Interface (USI) based on Programmable System on Chip (PSoC) from Cypress is presented and discussed. Multiple sensor interfaces are implemented in PSoC therefore a "sensor interface design library" is established. The dynamic reconfiguration, which is a key feature of USI, is also demonstrated. It allows USI to support multiple sensors in a time division fashion by in-circuit and run-time reconfiguration. Part of the sensor interfaces are tested and evaluated, proving both the hardware and software design. Finally the conclusion is made and future work is discussed as a guidance of the follow up work.

Pre-feasibility analysis on the optimization of the performance of the indirect tyre pressure monitoring system through a sensor fusion with a new generation of ultrasound parking sensors: from the idea to the development of macro project specifications and macro business case, with definition of the possible new scenario in terms of performance, costs and perceived quality

This PhD thesis introduces basic concepts of smart chemical sensors design, which are afterwards applied to a particular application: the analysis of natural gas. The thesis addresses thus two sets of objective, a first set of objectives related to the conceptual design of a smart chemical sensor using smart sensor standards: - The design of an optimal smart chemical sensor architecture - The novel combination in a working prototype of the highly complementary smart sensor standards IEEE-1451 and BS-7986 A second set of objectives is directly related to the selected application. Natural gas quality control. Natural gas is an energy source of major importance in the world energy supply, its quality control is increasingly important due to its origin-dependent properties and the progressive liberalization of the energy market. The objectives related to this application are: - To solve the natural gas quality analysis problem by using a lower cost approach taking advantage of MEMS technology, smart sensor features, and embedded intelligent signal processing. - To select suitable sensing technologies and associated signal processing. An overall goal addressed by the PhD Thesis is in the end the reporting of a working smart sensor prototype implementing all the smart sensor features, MEMS based natural gas analysis and advanced signal processing as a demonstration of a novel low-cost and high speed natural gas analyzer. The thesis covers this research along 7 chapters, introducing the concepts and application in chapters 1 and 2, the objectives in chapter 3, the simulation of a proposed MEMS sensor approach in chapter 4, the description of the advanced signal processing approach adopted in chapter 5, the description of the electronics and engineering of the smart natural gas analyzer prototype in chapter 6, and finally the conclusions of the work in chapter 7.
La tesis introduce conceptos básicos sobre el diseño de sensores químicos inteligentes, en particular presenta los estándares propuestos IEEE-1451 y BS-7986, y elabora una propuesta para el diseño óptimo de dichos sensores químicos inteligentes. Se implementa la propuesta de diseño para una aplicación concreta, el análisis de gas natural. Además de la aplicación de los conceptos sobre sensores químicos inteligentes se pretende además diseñar un analizador compacto, rápido y de bajo coste, para ello se estudia el uso de un microsensor termoeéctrico como sensor principal del analizador. Una vez probada su viabilidad se implementan ambos conceptos (sensores inteligentes y microsensor termoeléctrico) en un prototipo funcional validado en laboratorio. Como resultado se obtiene una propuesta para el diseño de sensores químicos inteligentes basada en estándares, y por otro lado se presenta un nuevo analizador de gas natural, más rápido y compacto que los existentes. Los resultados obtenidos originan diversas publicaciones en revistas así como dos patentes de método y sistema.

This dissertation focuses on the development, characterization, and analysis of luminescent materials and coatings for sensing applications, including CO2, heavy metals, and silver. Chapter 2 involves the use of a gold(I) pyrazolate trimer that is able to detect silver ions with an AgNP medium. Detection of silver is vital, because there is an influx of silver into our environment caused by the increased use of AgNP. Therefore, having a sensor that is able to differentiate between and detect only Ag ions is an important first step to solving the toxicity mystery of AgNPs. Chapter 3 focuses on the development of sensor coatings containing a Eu(III) based luminescent system for sensing dissolved CO2 without the aid of an absorption-based dye. It is well-known that monitoring CO2 levels in our environment is important since even at low concentrations it can cause adverse health effects to the human body. This work demonstrates a pH-sensitive Eu complex being used directly as a CO2 sensor without the aid of any other absorption-based dye. Chapter 4 explores the idea of developing a heavy metal sensor for lead and its ability to detect lead in wide concentration range upon changing the pH of the medium and the polymer matrix. Different heavy metals have toxicity at different concentrations, therefore, being able to change the dynamic range of the sensor is advantageous. This research is the first step towards developing a luminescent Pb sensor with a tunable dynamic range.

Os polímeros conjugados, principalmente da classe dos politiofenos, despontaram como materiais alternativos para a obtenção de camadas quimicamente seletivas em sensores de gases. Dentre as principais vantagens desses materiais estão a possibilidade de obtenção de dispositivos sensores que operem à temperatura ambiente e a diversidade de materiais. Assim, por exemplo, com uma simples modificação da cadeia lateral do politiofeno pode-se obter materiais com diferentes afinidades químicas, o que pode contribuir para a melhora da seletividade desses dispositivos. A seletividade e a sensibilidade são as maiores limitações práticas dos sensores de gases que utilizam os polímeros conjugados como camadas sensoras. Neste trabalho, diferentes derivados do politiofeno foram sintetizados via polimerização oxidativa com cloreto férrico e caracterizados químico-estruturalmente por FTIR, RMN 1H, HPSEC e análise térmica (TG). Filmes desses polímeros foram obtidos pelas técnicas spin-coating e casting, sendo que a escolha da técnica de preparo foi baseada na solubilidade desses polímeros em clorofórmio. Foi demonstrado que as características superficiais e as propriedades de absorção no Uv-vis e de emissão dos filmes desses politiofenos são influenciadas pelos tipos de cadeias laterais presentes nesses polímeros. Esses filmes foram também utilizados no estudo das suas propriedades sensoras óticas e elétricas para a detecção de VOCs e umidade, sendo demonstrado que os sensores óticos são menos sensíveis aos analitos propostos do que os sensores elétricos, apresentando valores de sensibilidades no intervalo de 10-7 a 10-5 ppm-1, respectivamente, com algumas exceções. As respostas de ambos os tipos de sensores contendo PHT foram qualitativamente e quantitativamente reprodutíveis, entretanto, as características de reprodutibilidade dos sensores elétricos de PHT apresentaram grande influência das condições elétricas iniciais de seus filmes. Diferentes padrões de detecção foram apresentados para as detecções óticas e elétricas de um determinado polímero, demonstrando que estes polímeros são bons candidatos para serem utilizados como camadas ativas em dispositivos de detecção de VOCs (compostos orgânicos voláteis).
The conjugated polymers, especially polythiophenes, have emerged as alternative materials to obtain chemically selective layers in gas sensors. The main advantages of these materials are the possibility of obtaining sensing devices that operate at room temperature and the diversity of materials. For example, a simple modification of the side chain of polythiophene can provide materials with different chemical affinities, which can contribute to the improvement of the selectivity of these devices. The selectivity and sensitivity are the main practical limitations of the gas sensors containing conjugated polymers as sensing layers. In this study, different polythiophene derivatives have been synthesized by oxidative polymerization with ferric chloride and characterized by FTIR, 1H NMR, HPSEC and thermal analysis (TG). Films of these polymers have been obtained by spin-coating techniques and casting, depending on their solubility in chloroform. It has been shown that the surface characteristics and the properties of absorption in the UV-vis and the emission of the films of these polythiophene derivatives are dependent on the type of side chain attached to the thiophene ring. These films have been used in the study of their optical and electrical sensing properties of VOCs and humidity, and it has been demonstrated that optical sensors are less sensitive to these analytes than the electrical ones. Their fractional sensitivities are 10-7 and 10-5 ppm-1, respectively, with some exceptions. The responses of such sensors have been qualitatively and quantitatively reproducible, however, the responses of electrical sensors showed influence of the initial electrical characteristics of the films. Different detections patterns were showed for optical and electrical detections of a particular polymer, showing that these polymers are good candidates to be used as active layers in sensing devices to detect VOCs.

Aquesta tesi tracta el desenvolupament, la fabricació i la caracterització de detectors de silici 3D fabricats al Centre Nacional de Microelectrònica (IMB-CNM) de Barcelona. Degut a l’actualització del High Luminosity- LHC del detector ATLAS i el possible Future Circular Collider, és necessària una investigació exhaustiva dels detectors de píxels 3D, utilitzats com sensors de traça de partícules. Cal avaluar les capacitats del detector i s’ha de desenvolupar una nova generació de dispositius que sigui capaç de complir amb els estrictes requisits dels col·lisionadors més potents. Els detectors de píxels 3D, ja emprats en Inserible B-Layer (IBL) i en l’ATLAS Forward Proton (AFP) (tots dos instal·lats en el detector ATLAS), es van fabricar amb tecnologia de doble cara amb una cel·la de píxel de 50x250 μm2 i gruix de 230 μm. La nova generació de sensors 3D per al detector Inner Tracker (ITK) d’ATLAS es fabricarà en tecnologia d’una sola cara amb cel·les de píxels de 50x50 μm2 i 25x100 μm2 i un gruix de 150 μm. La disminució de la mida dels píxels ve dictada per motius d’ocupació i té com a objectiu millorar la resolució espacial. Al passar de la primera (detectors 3D fabricats amb tecnologia de doble cara) a la nova generació (detectors 3D fabricats amb tecnologia d’una sola cara), es va produir un lot de I+D amb oblies de 230 μm de gruix i amb cel·les de píxels més petites; una investigació dels detectors de silici 3D irradiats a fluències com les esperades per al ITK és el tema de el capítol 3. A continuació, els capítols 4 i 5 estan dedicats als passos més importants per a la fabricació dels detectors en tecnologia d’una sola cara que es descriu en el capítol 6. Es presenten els detectors de píxels 3D amb nou disseny i la caracterització elèctrica es realitza a nivell d’oblia. Finalment, els dispositius pertanyents a les dues generacions són irradiats a fluències extremes i es presenta una primera investigació com a possibles detectors per a futures instal·lacions de col·lisionadors més potents.
Esta tesis está dedicada al desarrollo, a la fabricación y a la caracterización de los detectores de silicio 3D fabricados el en Centro Nacional de Microelectrónica (IMB-CNM) de Barcelona. En vista de la actualización de Alta Luminosidad- LHC del detector ATLAS y el posible Future Circular Collider, una investigación exhaustiva de los detectores de pixeles 3D, utilizados como sensores de traza de partículas, es necesaria. Es necesario evaluar las capacidades del detector y se debe desarrollar una nueva generación de dispositivos que sea capaz de cumplir con los estrictos requisitos de los colisionadores más potentes. Los detectores de pixeles 3D, ya empleados en Insertable B-Layer (IBL) y en ATLAS Forward Proton (AFP) (ambos instalados en el detector ATLAS), se fabricaron con tecnología de doble cara con una celda de pixel de 50x250 µm2 y un espesor de 230 µm. La nueva generación de sensores 3D para el detector Inner Tracker (ITk) de ATLAS se fabricará en tecnología de una sola cara con celdas de 50x50 µm2 y 25x100 µm2 y un grosor de 150 µm. La disminución del tamaño de los píxeles viene dictada por motivos de ocupación y tiene como objetivo mejorar la resolución y el nivel de tolerancia a la radiación. Al pasar de la primera (detectores 3D fabricados con tecnología de doble cara) a la nueva generación (detectores 3D fabricados con tecnología de una sola cara), se produjo un lote de I+D con obleas de 230 µm de espesor y con celdas de pixeles más pequeñas; una investigación de los detectores de silicio 3D irradiados a fluencias como las esperadas para el ITk es el tema del capítulo 3. A continuación, los capítulos 4 y 5 están dedicados a los pasos más importantes para la fabricación de los detectores en tecnología de una sola cara que se describe en el capítulo 6. Se presentan los detectores de pixeles 3D con nuevo diseño y la caracterización eléctrica se realiza a nivel de oblea. Finalmente, los dispositivos pertenecientes a las dos generaciones son irradiados a fluencias extremas y se presenta una primera investigación como posibles detectores para futuras instalaciones de colisionadores más potentes.
This thesis is devoted to the development, fabrication and characterisation of the 3D silicon detectors fabricated at the Centro Nacional de Microelectronica (IMB-CNM) in Barcelona. In the view of the High Luminosity-LHC upgrade of the ATLAS detector and the possible Future Circular Collider, a thorough investigation of the 3D pixel detectors, used as a tracking sensors, is necessary. The detector capabilities have to be evaluated and a new generation of devices that is able to fulfill the stringent requirements of the more powerful colliders must be developed. The 3D pixel detectors, already employed in Insertable B-Layer (IBL) and in ATLAS Forward Proton (AFP) (both installed in ATLAS detector), were fabricated in double sided technology with a pixel cell of 50x250 µm2 and thickness of 230 µm. The new 3D sensor generation for the Inner Tracker (ITk) of ATLAS detector upgrade will be fabricated in single sided technology with pixel cells of 50x50 µm2 and 25x100 µm2 and thickness of 150 µm. The decrease of the pixel dimensions are dictated by occupancy reasons and aims to improve the resolution and the level of the radiation tolerance. In going from the _rst (3D detectors fabricated in double sided technology) to the novel generation (3D detectors fabricated in single sided technology), a R&D batch of 230 µm thick wafers with smaller pixel cells was produced; an investigation of the 3D silicon detectors irradiated at fuences such as those expected for the ITk is the subject of chapter 3. Following that, chapters 4 and 5 are devoted to the more important steps for the manufacturing the detectors in single sided technology which is described in chapter 6. The 3D pixel detectors with new design are presented and the electrical characterisation is performed at the wafer level. Finally, the devices belonging to the two generations are irradiated at extreme fuences and first investigation as possible tracking detectors for future more powerful collider facilities is presented.
Universitat Autònoma de Barcelona. Programa de Doctorat en Física

Control de calidad sensorial de bebidas alcohólicas utilizando rápidos sensores químicos
En la presente tesis Doctoral, han sido aplicados dos sensores artificiales para el análisis de
bebidas alcohólicas: la nariz electrónica basada en la espectrometría de masas (MS) y la lengua
electrónica basada en la espectroscopía infrarroja con transformada de Fourier (FTIR). El
propósito fue desarrollar nuevas estrategias para analizar la autenticidad de estos productos,
desde un punto de vista sensorial, por medio de técnicas las espectrales antes mencionadas.
Adicionalmente, ha sido utilizado un espectrofotómetro UV-visible como ojo electrónico. El
trabajo presentado pretende ser un avance significativo hacia el desarrollo de un catador
electrónico mediante la fusión de los tres sensores químicos: nariz electrónica, lengua
electrónica y ojo electrónico.
Sensory quality control of alcoholic beverages using fast chemical sensors
In the present Doctoral Thesis, two chemical artificial sensors are applied to the analysis of
alcoholic beverages: the Mass Spectrometry (MS)-based electronic-noses and Fourier
transform infrared (FTIR)-based electronic-tongue. The aim was developing new strategies to
test the authenticity of these products, from a sensory point of view, by means of the spectral
techniques above mentioned. Additionally, has been used an UV-visible spectrophotometer as
electronic eye. The work presented wants to be a significant advance towards the development
of an electronic taster through the fusion of three chemical sensors: electronic nose, electronic
tongue and electronic eye.

Användandet av trådlösa sensorer inom byggindustrin är relativt nytt. Sensible solutions AB har utvecklat en produkt för fuktindikering som kan användas i t.ex. lätta utfackningsväggar. Systemet bygger på att två stycken passiva RFID-taggar fästs på ett kort med ett mellanrum så att inte taggarna stör varandra. Den ena är täckt med en fuktabsorberande pappersbit som tar upp fukt ur den omgivande luften medan den andra är öppen mot omgivande luft. Sensorerna avläses med en RFID-läsare som sänder ut signaler tills ett svar erhålls från båda taggarna. Den fuktiga taggen kommer att kräva en större signalstyrka för att avläsas än den torra på grund av förändringar i dess resonansfrekvens då taggen blivit fuktig. Då det krävs olika signalstyrkor för att ladda upp vardera taggen kan differensen mellan de båda användas som en fuktindikator. Sensorerna är relativt billiga och skulle kunna användas i stora mängder för att tidigt upptäcka läckage, eller höga fuktnivåer. Inom detta examensarbete har tester utförts för att avgöra hur tillförlitliga sensorerna är med avseende på avstånd och riktningar till avläsningsenheten samt inbördes avstånd mellan flera sensorer. Sensorerna har fått acklimatiseras i behållare med olika saltlösningar som ger relativa fuktigheter mellan 12-97 %. De har sedan blivit avlästa för att avgöra hur värdena av differensen i signalstyrka varierar med relativ fuktighet. Fördelar och begränsningar med metoden har undersökts dels genom litteraturstudier och dels genom de utförda testerna. Testerna visar att metoden är känslig för avstånd och riktningar. Dock beror troligtvis inte detta på sensorerna utan att den avläsningsenhet som används i dagsläget har en del begränsningar. Metoden kräver att någon avläser de manuellt på byggarbetsplatsen, t.ex. en platschef. I dagsläget finns endast en gräns för att avgöra om det är torrt eller fuktigt. Gränsen är 5 dBm skillnad mellan signalstyrkan för att ladda upp den fuktiga respektive den torra taggen. Testerna som gjorts inom detta examensarbete har visat att fuktigare luft innebär en större skillnad i signalstyrka mellan den öppna (referenstaggen) och den inneslutna taggen. Vid avläsning krävs att avläsningsenheten är riktad rakt mot kortet för att “korrekta” värden ska erhållas. En ny, bättre avläsningsenhet kommer att börja användas under februari 2012. Därmed kommer en ny uppgradering av den kritiska fuktnivån. ii
The using of RFID-sensors in the Building industri is relatively new. Sensible solutions AB have developed a product for moisture indication in for example light weight exterior walls. The system is built upon one pair of passive RFIDtags placed on a card with a space between them so that the tags don’t disturb one another. One of the tags is covered with a moisture absorbing paper and the other one is left open to the surrounding air. The sensors are read with an RFID-reader which sends out signals until a response is received from both of the tags. The moistened tag requires greater signal strength to be read than the dry one because of changes in its resonance frequency when the tag is covered in moisture. Since different signal strengths are required to read the two tags, the difference between them can be used as a moisture indicator. The sensors are relatively cheap and could therefore be used in great amount to early discover leakage and high moisture levels. Within this master thesis, tests have been made to evaluate how reliable the sensors are in regard to distance between the reader and the sensors, the angle between them and the distance between several different sensors. The sensors have been acclimatized in exicators with different salt solutions which are emitting relative humidity’s between 12-97 %. They have then been read to determine how the values in the difference in signal strength varies with relative humidity. The pros and cons with the method have been studied through literature and the tests made. The tests show that the method is sensitive to distances and angles. However the limitation doesn’t depend on the sensors, but of the reader that is used today. The method requires that someone is reading the sensors manually on the construction site, for instance a construction site manager. Today there is only one limit to determine if it’s dry or damp. The limit is 5 dBm differences in power up level between the damp and the dry tag. The tests made in this thesis shows that a higher moisture level leads to a greater difference in signal strength between reading the open and the covered tag. When reading the sensors it requires that the reader is aimed straight toward the sensor so that “correct” values will be received. A new, better reader will be used in February 2012. Consequently a new upgrade of the critical moisture level will be made. iii

The great interest in monitoring everything around us has increased the number of sensors that we utilize in our daily lives. Furthermore, the evolution of wireless technologies has facilitated their ubiquity. Moreover, is in locations such as homes and offices where exploitation of the data from these sensors has been more important. For example, we want to know if the temperature in our home is adequate, otherwise we want to turn on the heating (or cooling) system automatically and we want to be able to monitor the environment of the home or office remotely. The knowledge from these sensors and the ability to actuate devices, summon human assistance, and adjust contracts for electrical power, heating, cooling, etc. can facilitate a myriad of ways to improve the quality of our life and potentially even reduce resource consumption. This master‘s thesis project created a gateway that sniffs wireless sensor traffic in order to collect data from existing sensors and to provide this data as input to various services. These sensors work in the 868 MHz band. Although these wireless sensors are frequently installed in homes and offices, they are generally not connected to any network. We designed a gateway capable of identifying these wireless sensors and decoding the received messages, despite the fact that these messages may use a vendor‘s proprietary protocol. This gateway consists of a microcontroller, a radio transceiver (868-915 MHz), and an Ethernet controller. This gateway enables us to take advantage of all the data that can be captured. Thinking about these possibilities, simultaneously acquiring data from these various sensors could open a wide range of alternatives in different fields, such as home automation, industrial controlling… Not only can the received data be interesting by itself; but when different sensors are located in the same environment we can exploit this data using sensor fusion. For example, time differences in arrival and differences in signal strength as measured t multiple receivers could be used to locate objects. The final aim of this thesis project is to support diverse applications that could be developed using the new gateway. This gateway creates a bridge between the information that is already around us and our ability to realize many new potential services. A wide range of opportunities could be realized by exploiting the wireless sensors we already have close to us.
Det stora intresset för att övervaka allt omkring oss har ökat antalet sensorer som vi använder i vårt dagliga liv. Dessutom har utvecklingen av trådlösa tekniker underlättat de har stor utbredning. Dessutom är på platser som hem och kontor där utnyttjandet av data från dessa sensorer har varit viktigare. Till exempel vill vi veta om temperaturen i vårt hem är tillräcklig, annars vill vi slå på värmen (eller kyla) automatiskt och vi vill kunna övervaka miljön i hemmet eller på kontoret på distans. Data från dessa sensorer och förmåga att aktivera enheter kalla mänsklig assistans och justera avtal för el, värme, kyla, osv. kan underlätta en myriad av olika sätt att förbättra kvaliteten på våra liv och potentiellt även minska resursförbrukningen. Detta examensarbete syftar till att sniffa trådlösa sensorn trafik i syfte att samla in data från befintliga sensorer och att tillhandahålla sådan information som underlag till olika tjänster. Dessa sensorer arbetar i 868 MHz-bandet. Även om dessa ofta installeras i hem och kontor, är de i allmänhet inte ansluten till något nätverk. För att förverkliga vårt mål kommer vi att utforma en gateway som kan identifiera dessa trådlösa sensorer och avkoda den mottagna meddelanden, trots att dessa meddelanden kan använda en leverantör egenutvecklade protokoll. Denna brygga består av en mikrokontroller, en sändtagare (868 till 915 MHz), och en Ethernet-styrenhet. Gateway bör göra det möjligt för oss att dra nytta av alla de uppgifter som möjligen kan fångas. Funderar om dessa möjligheter, samtidigt insamling av data från dessa olika sensorer kan öppna ett brett spektrum av alternativ i olika områden, såsom hem automation, industriell kontrollerande ... Inte bara kan de mottagna uppgifterna vara intressant i sig självt, men när olika sensorer finns i samma miljö kan vi utnyttja detta data med hjälp av sensor fusion. Till exempel skulle tidsskillnader i ankomst och skillnader i signalstyrka uppmätt med flera mottagare användas för att lokalisera föremål. Det slutliga målet med denna avhandling är att stödja olika applikationer som skulle kunna utvecklas med hjälp av utformade gateway. Denna gateway kommer att skapa en initial brygga mellan all information omkring oss och vår förmåga att förverkliga många tjänsteleverantörer möjligheter. Ett brett utbud av möjligheter kan realiseras genom att utnyttja de trådlösa sensorerna vi redan har nära till oss.

The aim of the diploma thesis is to get acquainted with possibilities of realization of a multifunctional sensor for agricultural purposes. The theoretical work deals with the principles of measurement of environmental variables. Subsequently, sensors are selected which can measure the environmental variables. The thesis discusses the possibilities of wireless communication. Attention is paid to the communication modules of the DIGI® manufacturer. The main part describes the physical implementation of the multifunctional sensor. Here is a detailed breakdown of what components are selected for implementation with adherence to general implementation requirements. At the end of the work is described a program serving multifunctional sensor.

Surface Plasmon Resonance (SPR) sensors are thin-film refractometers that measure changes in the refractive index that take place at the surface of a metal film supporting a surface plasmon (Homola, 2008). The research activity consisted on a study and realization of innovative Surface Plasmon Resonance based sensors and of their applications, in particular for the environment monitoring. In order to investigate the possibility of creating innovative SPR sensors, computer simulations of optical structures supporting surface plasmon polaritons and comprising peculiar materials were implemented. In particular SPR sensors based on metals showing Inverted Surface Plasmon Resonance and a single layer of Graphene (SGL) were simulated. An article has been submitted on this study. Surface Plasmon Resonance sensor prototypes were also realized in laboratory. By means of a first SPR sensor with dynamic setup, measurements with Helium and Pentane gases were made, then an SPR sensor with a static setup was assembled, refined and as a following improvement in the optical components an adaptive mirror also introduced, which was able to counteract, if present, a lens defocus, spherical aberration, coma and astigmatism . Moreover the elements of a feasible wireless sensor network based on Surface Plasmon Resonance sensors, the possible data that can be inferred from a SPR sensor and a possible data handling strategy were determined along with an evaluation of the sensor module energy requirements. Then two small wireless sensor network test setups were implemented in laboratory, each one composed of two SPR sensors controlled by a computer or a microcontroller, ZigBee antennas and a main computer for the data reception and diffusion into Internet. The feasibility of a Wireless Sensor Network based on SPR sensors, conceived for environmental pollutants detection and with broadband internet connection, has been demonstrated and two different laboratory setups for a test Wireless Sensor Network based on Surface Plasmon Resonance Sensors were realized.
I sensori basati sulla plasmonica di superficie (SPR) sono rifrattometri, basati sulla fisica dei film sottili, che misurano le variazioni di indice di rifrazione che avvengono sulla superficie di uno strato metallico supportante un plasmone di superficie (Homola , 2008). L’ attività di ricerca si è sviluppata come uno studio ed implementazione di sensori SPR innovativi e delle loro possibili applicazioni, in particolare per la rilevazione di sostanze inquinanti. Sono stati simulati in ambiente Matlab sensori SPR innovativi, comprendenti materiali peculiari. Tali sensori comprendono in particolare metalli mostranti una Risonanza Plasmonica Invertita (ISPR), oltre che un singolo strato di Graphene (SGL). Un articolo è stato sottomesso su tali studi. Sono stati inoltre implementati in laboratorio vari prototipi di sensori basati sulla plasmonica di superficie. Innanzi tutto sono state effettuate delle misure di riflettività con i gas elio e pentano mediante un sensore basato sulla plasmonica di superficie e con un setup dinamico, quindi è stato creato un nuovo sensore utilizzante un un sistema ottico di tipo statico ed un prisma cilindrico ad alto indice di rifrazione, migliorando il più possibile la qualità del fascio ottico e filtrandolo opportunamente. Altresì è stato innovativamente utilizzato nel setup ottico uno specchio deformabile, in grado di correggere le aberrazioni ottiche presenti nello stesso. Oltre a ciò sono stati individuati i possibili elementi di una rete wireless di sensori SPR progettata per il monitoraggio ambientale, i dati ottenibili da un sensore SPR, una strategia per la diffusione dei dati ed una stima dei consumi energetici. Infine sono stati implementati in laboratorio due diversi setup di prova per una piccola rete wireless di sensori, formata da due sensori SPR controllati da un computer o da un microcontrollore, antenne ZigBee e da un computer principale per la ricezione, analisi e diffusione in Internet dei dati. L’ attività di ricerca presentata in questa tesi ha quindi dimostrato la possibilità della creazione di una rete wireless di sensori basati sulla Plasmonica di Superficie e con accesso Internet a banda larga, finalizzata alla rilevazione di sostanze inquinanti in ambiente acquoso, e due piccole versioni di prova della stessa sono state implementate in laboratorio.

When developing algorithms for autonomous vehicles it is important to test several different scenarios many times. New and untested algorithms are prone to make errors which results in accidents. It is therefore preferred to use a simulation environment instead. Sensors used to determine the vehicle’s position must then be modelled. This thesis answers the question whether adding sensor simulation to an existing simulation platform (AGXUnity) is viable, or if using other existing options is preferred. To reach the goal, a function-based sensor is developed and its accuracy tested. Its performance is determined by simulation in a standard scene. Tests showed that the sensor had acceptable accuracy and performance. The conclusion is that AGXUnity is a viable platform for sensor simulation.

La rapida diffusione e la grande popolaritá di laptops, smartphones,PDAs, dispositivi GPS e altri apparecchi elettronici nell'era post-PC, hanno alimentato la tendenza di produrre apparecchi elettronici sempre piú portatili, versatili e a buon mercato, con capacitá di calcolo sempre piú elevate. I continui progressi tecnologici hanno condotto ad un'abbondante disponibilitá di microprocessori e microcontrollori sempre piú piccoli ed economici, equipaggiati con sensori sempre piú avanzati, storage e dotati di connessione wireless. In quest' ottica si colloca l'emergere di una nuova tipologia di reti di telecomunicazioni: le Wireless Sensor Networks (WSNs), le quali rappresentano pienamente l'ultima tendenza della famosa legge di Moore nei confronti della miniaturizzazione e dell'ubiquitá dei dispositivi elettronici. L'integrazione di capacitá di calcolo, memorizzazione e comunicazione in dispositivi di dimensioni ridotte e a basso costo ha portato alla de finizione delle WSNs. Le reti di sensori sono state pensate come possibili strumenti per l'activity recognition in campo biomedico, i risultati di tale applicazione mostrano come questa essa sia molto e fficace nel monitoraggio della azioni di pazienti. Viene inoltre presentata un applicazione realizzata attraverso una WSN. Si tratta di un un applicazione per HRV (Heart Rate Variability). L'HRV é basata sull'analisi tempo-frequenza degli intervalli R-peak raccolti da un segnale ECG. Tale studio propone un toolkit realizzato attraverso una rete di sensori wireless per l'analisi temporale dell'HRV, chiamata SPINE-HRV (Signal Processing In Node Environment SPINE). SPINE-HRV é composto da un sistema indossabile per il monitoring dell'attivitá cardiaca in grado di raccogliere continuamente gli R-peak e un applicazione in grado di processare cosí i dati raccolti. L'analisi fatta attaverso lo SPINEHRV toolkit fornisce sette parametri ben noti in letteratura medica in grado di aiutare i cardiologi nella diagnosi relativa a diverse problematiche. Inoltre tale toolkit fornisce uno strumento automatico per rilevazione di stati di stress acuti rilevabili durante tutte le attivitá svolte quotidianamente. Nella seconda parte verrá presentata una panoramica sui media gateway in particolare sui transcoder video per gli standard di codi ca video H.263+ e H.264. L'eterogeneitá sempre piú diffusa dei dispositivi presenti all'interno della rete Internet, rende necessaria lo sviluppo di dispositivi hardware o software in grado da permettere una a dabile intercomunicazione tra tali diversi dispositivi. In particolare si mostrerá come é possibile riutilizzare i modi Intra estratti durante il processo di decodi fica per aumentare l'efficienza della codifi ca in altro standard di codi ca video. Sono stati sviluppati due algoritmi in grado di selezionare attraverso una decisore a soglia, utilizzato sia per i modi 4x4 che 16x16. Verranno presentati le prestazioni in termini di PSNR e tempi di elaborazione confrontati con quelle relative l'approccio full transcoding. Tali risultati mostrano come siano stati ottenuti signi ficativi riduzioni dei tempi computazionali pur mantenendo un livello di PSNR confrontabile con quello relativo al processo di full transcoding.
With the wide diffusion and popularity of laptops, cell-phones, Personal Digital Assistants (PDAs), GPS devices and other intelligent electronic in the post-PC era, computing devices have become more portable, mobile and cheap. Nowadays the electronic in uences the daily life of each man and many tasks hard to do in the past now have become reality and easy to perform thanks to the signi cant advances in technology. From this viewpoint the emergence of wireless sensor networks (WSNs) is essentially the latest trend of Moore's Law toward the miniaturization and ubiquity of computing devices. Wireless sensor networks are used in order to perform activity recognition in heath care eld, the results of this application show how that it is effective in patient's actions monitoring. Moreover an application regarding Heart Rate Variability (HRV)will be presented. This work is based on the analysis of the Rpeak to R-peak intervals (RR-intervals) of the ECG signal in the time and/or frequency domains. Doctors and psychologists are increasingly recognizing the importance of HRV; in fact, a number of studies have demonstrated that patients with anxiety, phobias and posttraumatic stress disorder consistently show lower HRV,even when not exposed to a trauma related prompt. Importantly,this relationship existed independently of age, gender, trait anxiety, cardio-respiratory tness, heart rate, blood pressure and respiration rate. The SPINE-HRV is composed of a wearable heart activity monitoring system to continuously acquire the RR-intervals, and a processing application developed using the SPINE framework. The RR-intervals are processed using the SPINE framework at the base station side through a time-domain analysis of HRV. The analysis provides seven common parameters known in medical literature to help cardiologists in the diagnosis related to several heart diseases. In particular, SPINE-HRV is applied for stress detection of people during activities in their everyday life. Experimentations carried out by monitoring subjects in speci c activities have shown the effectiveness of SPINE-HRV in detecting stress. Currently few research prototypes based on BSNs exist that allow for HRV analysis. However SPINE-HRV represents the fi rst prototype using a wireless chest belt so making the system more comfortable than systems using wired electrodes or handheld devices. Furthermore, because the chest belt is a commercial product for sport and tness activities, it has been designed to be robust against body movements. SPINE-HRV is currently applied to stress detection that is computed through an effective threshold based algorithm. The experimentation of such an application has been carried out on different subjects performing different activities of the everyday life: walking, working at the PC, watching TV, sleeping, and driving. The obtained result are interesting as they show that SPINE-HRV is able to detect stress by performing only a time-domain analysis of HRV with respect to more complex computational methods based on the frequency-domain analysis. Thus, SPINE-HRV can be actually used to detect stress of human beings in real-time. Currently, we are focusing our research efforts in improving the stress analysis algorithm by introducing frequency domain features as well as comparing the obtained results to the clinical blood test for the stress hormone, which has been identi ed by the medical community as the quantitative measurement of the emotional stress level. In the second part of this thesis will be described two smart video transcoder processes in order to develop a media gateway. The aim of this network device is to bring about a conversion of the input bitstream into another one characterized by a different video codec. The codecs involved in the transcoding algorithm are the H.263+ (Annex I) and the H.264 baseline pro le. The scope of this study focuses on the possibility of reusing the Intra modes extracted from the input bitstream. Regarding H.263+ to H.264 transcoding, two different thresholds are evaluated for 4x4 blocks and 16x16 macroblocks: all the incoming modes that lead to costs over threshold are rejected and a re-estimation is performed. Otherwise, the incoming Intra mode is directly passed to the H.264 encoder. On the other hand, all the H.264 Intra modes are mapped into the H.263+ Intra modes and passed to the H.263+ encoder skipping the Intra prediction stage. Performance in terms of PSNR and elaboration time of our algorithms are compared to that of the full transcoding approach. A high correlation with PSNR scores is obtained and a significant reduction of computational burden for both transcoding processes is also achieved. The two video transcoder architectures are proposed in order to perform the H.263+ to H.264 conversion and vice versa. Referring to the rst transcoder, two adaptive thresholds are implemented. Both thresholds, used for 4x4 Intra block mode decision and 16x16 Intra block mode decision, vary according to the overall macroblock cost in order to consider the level of detail of the under-study macroblock. This solution is an innovation relating to the approaches proposed in literature based on the usage of a single xed threshold. We can assert that these algorithms represent a basis for the implementation of a low complexity fast transcoder for real-time applications thanks to the low complexity of the modi cation introduced, and also for the reduced computational burden of the entire trancoding process. In fact, we demonstrate a decrease of about 32% in the overall elaboration procedure using an arbitrary QP. The proposed platform also shows high reliability in terms of perceived quality. This is confi rmed by PSNR evaluations for fast transcoding output. PSNR differences are limited to 0.1 dB for all sequences used in the tests. So, the quality of the full transcoding output is very close to the one obtained by the fast transcoding technique. In addition, the overall increase in the bitrate is less than 12%. The H.264 to H.263+ transcoder uses a mapping between the incoming H.264 modes that is rather different to the one proposed in literature. The obtained results, using several standard sequences and QP, show that the overall quality is the same for the output bitstream obtained by the full transcoder and the proposed smart transcoder algorithm, and the bitrate increase is limited to 9% in the worst case. With this mapping it is possible to cancel the computational burden of the Intra mode prediction process. All these considerations allow us to assert that the proposed algorithm can be used in real-time transcoding architectures. Similar analysis concerning Inter frame pictures are actually under study by the authors in order to reduce the complexity of motion estimation procedure in transcoding architectures.

New millimeter wave interferometric, multifunctional sensors have been studied for industrial sensing applications: displacement measurement, liquid-level gauging and velocimetry. Two types of configuration were investigated to implement the sensor: homodyne and double-channel homodyne. Both sensors were integrated on planar structure using MMIC (Microwave Monolithic Integrated Circuit) and MIC (Microwave Integrated Circuit) technology for light, compact, and low-cost design. The displacement measurement results employing homodyne configuration show that sub-millimeter resolution in the order of 0.05 mm is feasible without correcting the non-linear phase response of the quadrature mixer. The double-channel homodyne configuration is proposed to suppress the nonlinearity of the quadrature mixer and to estimate the effect of frequency stability of a microwave signal source without the help of additional test equipment, at the loss of a slight increase of circuit complexity. The digital quadrature mixer is constituted by a quadrature-sampling signal processing technique and takes an important role in the elimination of conventional quadrature mixer's nonlinear phase response. Also, in the same displacement measurement, the radar sensor with the double-channel homodyne configuration provided a better resolution of 0.01mm, the best-reported resolution to date in terms of wavelength in the millimeter wave range, than the sensor employing simple homodyne configuration. Short-term stability of a microwave signal source, which is an important issue in phase sensitive measurement, is also considered through phase noise spectrum obtained by FFT spectral estimator at Intermediate Frequency (IF). The developed sensors demonstrate that displacement sensing with micron resolution and accuracy and high-resolution low-velocity measurement are feasible using millimeter-wave interferometer, which is attractive not only for displacement and velocity measurement, but also for other industrial sensing applications requiring very fine resolution and accuracy.

Microwave resonant sensors use the spectral characterisation of a resonator to make high sensitivity measurements of material electromagnetic properties at GHz frequencies. They have been applied to a wide range of industrial and scientific measurements, and used to study a diversity of physical phenomena. Recently, a number of challenging dynamic applications have been developed that require very high speed and high performance, such as kinetic inductance detectors and scanning microwave microscopes. Others, such as sensors for miniaturised fluidic systems and non-invasive blood glucose sensors, also require low system cost and small footprint. This thesis investigates new and improved techniques for implementing microwave resonant sensor systems, aiming to enhance their suitability for such demanding tasks. This was achieved through several original contributions: new insights into coupling, dynamics, and statistical properties of sensors; a hardware implementation of a realtime multitone readout system; and the development of efficient signal processing algorithms for the extraction of sensor measurements from resonator response data. The performance of this improved sensor system was verified through a number of novel measurements, achieving a higher sampling rate than the best available technology yet with equivalent accuracy and precision. At the same time, these experiments revealed unforeseen applications in liquid metrology and precision microwave heating of miniature flow systems.

The objective of my research is to develop new surface optochemical sensors for studying cellular processes by investigating techniques to modify surface properties. The spectral characteristics of the modified surfaces and coatings are designed to show remarkable changes after interaction with analytes from biological fluids and cells. My studies focused on pancreatic cells and addressed the need for improved techniques to measure zinc release from pancreatic cells (chapter 3, 4) and to measure the metastasis potential of cancerous pancreatic cells (chapter 5). Chapter 3 describes the development of zinc sensing glass slides by conjugating a carboxylmodified ZnAF-2 to an amino functionalized glass surface. The sensor was used for the measurement of glucose-stimulated zinc ion release from cultured beta pancreatic cells with impact in diabetes research. In chapter 4 is described conjugation of the carboxyl-modified ZnAF-2 to antibody molecules (A2B5) that specifically recognize pancreatic cells. This enabled for the first time the use of targeted zinc sensors to monitor zinc release events from pancreatic cells. Chapter 5 describes development for the first time of a fluorescence sensor to measure the proteolysis activity of pancreatic cancer cells in microfluidic systems. The sensor was fabricated using a Layer by layer (LbL) deposition of polyelectrolyte. The sensor was based on Fluorescence Resonance Energy Transfer (FRET) between luminescent quantum dots (serve as donors) and rhodamine molecules (serve as acceptors) that are separated by multi-layers of polyelectrolytes. The microfluidic platform enables precise delivery of reactants to assemble the sensor and facilitate unique cellular assays of enzymatic activity and enzymatic expression on pancreatic cancer cells.

The technology and applications of optical fibers have progressed very rapidly in recent years. Fiber-optic sensors have been commercially successful and well established in various industries from biomedical to defense. They exhibit many advantages over their electrical counterparts, including higher responsivity, higher detection bandwidth, higher temperature performance, better immunity to electromagnetic interference, all-dielectric composition, greater environmental ruggedness and distributed sensing capability. However, the physical dimensions and the minimum bend radius of the optical fiber sets a lower limit on the final package size. In applications where the working space is stringent or where physical intrusion must be minimized, it becomes highly desirable to develop ultra-compact sensors that can maintain the level of performance despite the miniaturization. The recent emergence of optical microfibers has opened up a new era of technological innovations. Microfibers have the potential to solve the problem with its range of enabling properties, including large evanescent field, strong optical confinement, bend insensitivity, low stiffness and high configurability. This thesis focuses on the innovative development of relatively unexplored areas of microfiber-based sensing as well as the envisioning of performance-enhancing techniques that can shape the on-going development of such sensors. In particular, extensive advancement was made in light of the simple demonstration of a novel current sensor with potentially gigahertz detection bandwidth. This includes the development of the resonator design to achieve higher compactness, and the first reported fabrication of the spun optical microfiber to counter the effects of linear birefringence. Well established and successfully proven sensing configurations such as the flexural disc and air-backed mandrel were adopted to create miniaturized microfiber-based accelerometers and microphones, with potential responsivity enhancements of at least one order of magnitude.

Mestrado em Engenharia Eletrónica e Telecomunicações
Nowadays buildings are being progressively integrated with an increasing number of sensors . Most of the times this sensors have quite speci c functions, butane sensors, propane sensors, carbon monoxide sensors, pyroelectric motion sensors, and this is what limits their eld of action. Introducing a certain level of autonomy to a sensor, i.e., send, process and receiving information can increase the interactivity and market attractiveness of a building. Within this point of view, and over-viewing the building conjuncture, it can be concluded that smart sensors will be installed during the construction, in recently constructed buildings, but also in buildings with several years which commonly have an physical electric network. This implies that this type of units will need to have an option to be retro tted and, to a certain degree, a simple installation. In this thesis, it is proposed the creation of an integrated solution using the wall of a room as a human interface. This system can establish communication with the gateway of a smart home using a previous researched, e cient and safe wireless protocol. Once the connection is established the gateway can execute a large variety of functions that can be programmed in the home central unit (gateway). The thesis hereby presented consists in a study of wireless communication protocols with respect to reliability, safety and practicality and in the research of the fusion between sensors, processing ability and communication interfaces with the intent of producing a prototype.
As habitações actuais são incorporadas com uma variedade cada vez mais vasta de sensores e actuadores. Estes sensores, na maioria das situações, tem uma função bastante especifica, sensores de gás butano, sensores de gás propano, sensores de monóxido de carbono, sensores piroeletricos. Através da introdução de autonomia a cada um destes sensores, nomeadamente, enviar, processar e receber informação, e possível tornar uma habitação num centro de partilha de informações fulcrais, acessível a partir de qualquer ponto. Nesta perspectiva, analisando a conjuntura habitacional deduz-se rapidamente que a aplicação de sensores inteligentes nao poderá ser feita apenas em novas habitações mas também terá que ser implementada em habitações que já possuem uma rede eléctrica implementada. Isto implica desde logo, que este tipo de equipamentos possam ser adaptados a redes que estão em utilização (retrotting) e que sejam de fácil acesso durante a instalação e manutenção. Desta forma entram em cena os protocolos de comunicação sem fios. Estes permitem nao somente a interligação dos sensores inteligentes (sensor, processador, interface de comunicação), mas também a sua ligação a actuadores e a interfaces pessoa-máquina, sem se por a necessidade de alterações físicas das habitações. A criação de uma soluçao integradora, utilizando a parede de uma habitação como interface humana e apresentada ao longo deste documento. Este sistema comunica com o gateway de uma casa inteligente utilizando a tecnologia wireless que será estudada e definida como a mais eficiente e segura. Uma vez interligada com o gateway poderá efectuar um conjunto vasto de operações, que estarão definidas no processador da unidade central da casa. A dissertação aqui apresentada consiste na analise de protocolos de comunicação wireless, e na concepção de um sistema de interface humana embutido nas paredes de edifícios habitacionais.

NOx-sensorn är grundläggande i det moderna efterbehandlingssystemet och dess pålitlighet är avgörande för att kunna leva upp till rådande emissionslagkrav. Livslängden samt sensorns beteende i slutet av denna varierar betydligt. Om en NOx sensor med oberäkneligt beteende inte upptäcks av fordonets styrsystemet kan det orsaka omfattande verkstadsbesök eller i värsta fall brott mot emissionslagkrav. Examensarbetet involverar identifiering av olika sensorfellägen, tidiga tecken till dessa fellägen, förstå och identifiera förhållanden mellan olika sensorparametrar och analysera sensorbeteendet vid sensorlivslängdens slutskede. NOx sensorn är en relativt ny sensor och fordonsindustrin har ännu inte en fullständig förståelse för dess beteende. Litteraturstudien täcker olika fellägena så som fastnat värde, förskjutet värde, förstärkning av värdet, felaktiga svängningar samt långsam respons. Även effekterna av åldrande i NOx sensorn beskrivs. Litteraturstudien diskuterar också diagnoser av sensorer i allmänhet samt diagnoser specifikt för NOx sensorer. Uppsatsarbetet involverar också en experimentell studie där NOx sensorer utsätts för statiska och fluktuerande gasflöden i en motortestbädd. Fellägen i NOx sensorer kan observeras i parametrarna för NOx-värde och oxidationsnivå. I den version av NOx sensorn som användes observerades det också att parametrarna felaktig NOx och felaktig O2 visar samma felkod samtidigt. Dock är inte parametrarna för felaktig NOx och felaktig O2 relaterade till parametrarna för värmningsstatus, felaktig värmare och värmeelementets temperatur. Sensorns status gällande ogiltiga NOx-mätningar är större än eller lika med antalet ogiltiga O2-mätningar. Resultatet gäller framför allt sensormodell Continental 2.8 NOx sensorer. Även logik för en monitor gällande felaktiga svängningar utvecklas baserat på standardavvikelse och NOx statusparametern för ogiltig mätning.
The NOx sensor is essential in the modern after-treatment system and the reliability of the sensor is crucial for any emission-based legislation. The life span of a sensor varies a lot as well as the behaviour previous to its end of life. If a NOx sensor with erratic behaviour is not discovered by the control system it may cause extensive workshop effort or in worst case exceed legal requirements. The thesis work involves identifying different sensor failure modes, precursors to these failure modes, understanding and identifying relationships between different sensor parameters, and analysing the sensor behaviour especially towards the end of life. The NOx sensor is a relatively new sensor and the vehicle industry does not yet have a complete understanding of its behaviour. The literature study covers the different failure modes namely stuck, offset, gain, oscillations, and slow response and their causes along with the effects of ageing in NOx sensors. It also discusses the diagnosis of faulty sensors in general and faulty NOx sensors. The thesis work also involves an experimental study where the NOx sensors are subjected to static and transient gas flow tests in an engine testbed. Failure modes in NOx sensors are observable in NOx concentration and actual oxidation measurement parameters. It was also observed in the version of the NOx sensor used that Error NOx and Error O2 parameters show the same fault code at the same time. Although, the Error NOx and Error O2 parameters are not related to the heater parameters, Heater status, Error heater, and Temperature of heating element. The number of invalid flags set in NOx status is greater than or equal to the number of invalid flags in O2 status. The mentioned parameters are concerning Continental 2.8 NOx sensors. The logic for the oscillatory fault monitor is developed based on standard deviation and an invalid flag check on the NOx status parameter.

The usage of inertial sensors has traditionally been confined primarily to the aviation and marine industry due to their associated cost and bulkiness. During the last decade, however, inertial sensors have undergone a rather dramatic reduction in both size and cost with the introduction of MEMS technology. As a result of this trend, inertial sensors have become commonplace for many applications and can even be found in many consumer products, for instance smart phones, cameras and game consoles. Due to the drift inherent in inertial technology, inertial sensors are typically used in combination with aiding sensors to stabilize andimprove the estimates. The need for aiding sensors becomes even more apparent due to the reduced accuracy of MEMS inertial sensors. This thesis discusses two problems related to using inertial sensors in combination with aiding sensors. The first is the problem of sensor fusion: how to combine the information obtained from the different sensors and obtain a good estimate of position and orientation. The second problem, a prerequisite for sensor fusion, is that of calibration: the sensors themselves have to be calibrated and provide measurement in known units. Furthermore, whenever multiple sensors are combined additional calibration issues arise, since the measurements are seldom acquired in the same physical location and expressed in a common coordinate frame. Sensor fusion and calibration are discussed for the combination of inertial sensors with cameras, UWB or GPS. Two setups for estimating position and orientation in real-time are presented in this thesis. The first uses inertial sensors in combination with a camera; the second combines inertial sensors with UWB. Tightly coupled sensor fusion algorithms and experiments with performance evaluation are provided. Furthermore, this thesis contains ideas on using an optimization based sensor fusion method for a multi-segment inertial tracking system used for human motion capture as well as a sensor fusion method for combining inertial sensors with a dual GPS receiver. The above sensor fusion applications give rise to a number of calibration problems. Novel and easy-to-use calibration algorithms have been developed and tested to determine the following parameters: the magnetic field distortion when an IMU containing magnetometers is mounted close to a ferro-magnetic object, the relative position and orientation of a rigidly connected camera and IMU, as well as the clock parameters and receiver positions of an indoor UWB positioning system.
MATRIS (Markerless real-time Tracking for Augmented Reality Image), a sixth framework programme funded by the European Union
CADICS (Control, Autonomy, and Decision-making in Complex Systems), a Linneaus Center funded by the Swedish Research Council (VR)
Strategic Research Center MOVIII, funded by the Swedish Foundation for Strategic Research (SSF)

Inexpensive instruments that measure concentrations of airborne particles in workplaces have grown to become an efficient way to estimate personal aerosol exposure of workers. This study evaluates the performance of two types of inexpensive instruments: an “active” version which pulls particle-laden air into a sensing zone for measurement, and a “passive” version which does not. The response of these instruments to clean air over time was evaluated as an indicator of contamination in laboratory and factory settings. Additionally, the effect cleaning of the instruments had on performance was evaluated. After exposure to high concentrations of particles in the laboratory, the active and passive versions of the instruments lost partial to full ability to detect particle concentrations. In the factory, this change was only seen in the active version, and occurred over a longer amount of time. Cleaning of the instruments returned some ability to detect particles, but not to the ability a new instrument. The accumulation of particles within instruments used to estimate aerosol exposures can affect the output of and overall performance of the instruments. Cleaning of the instruments after accumulation results a lessening of the effect, but not completely. Cleaning can be a way to extend the lifetime of these instruments. However, the time and financial costs related to cleaning several sensors within a workplace should be considered.

Insects have evolved very elaborate sensing systems. The airflow sensors of crickets are among the most sensitive sensors in the animal world. The sensor comprises a thin hair, which protrudes from the surface of the cuticle and sits in a specialised socket. Its elliptical base is surrounded by a flexible joint membrane to allow the hair to rotate. The polarity of the base restricts the rotation of the hair to a preferred plane of movement. The results of the morphometric analysis of the airflow sensors presented in this study show that the maximal diameter of the hair is a strong predictor for the other parameters determining the sensors geometry, such as the hair length, its socket geometry, as well as the hair's elliptical base, which is otherwise hidden within the socket and out of view unless the hair and its base are removed.

Sistemas de vigilância são geralmente empregados no monitoramento de áreas de grandes dimensões nas quais seus usuários visam detectar ou observar fenômenos de seu interesse. O uso de redes de sensores sem fio nesses sistemas apresenta especial interesse, uma vez que essas redes podem apresentar soluções de baixo custo e robustas para cobrir áreas extensas. Neste contexto, novas aplicações têm surgido propondo o uso de redes de sensores sem fio compostas por nós sensores estáticos e móveis. Uma das motivações para esta tendência é a redução do custo de implantação e operação do sistema, além da possibilidade de proporcionar incremento em suas funcionalidades. O foco desta tese se concentra na proposta de soluções para redes de sensores sem fio com uso cooperativo de sensores estáticos e móveis, com particular atenção a sensibilidade ao contexto na configuração e execução de missões de sensoriamento. O objetivo é manter um baixo custo de comunicação associado às soluções propostas. Esta preocupação se dá pelo fato da comunicação aumentar o consumo de energia em redes de sensores, o que é um problema importante para nós sensores com limitada fonte de energia, i.e. baterias. No caso de nós sensores móveis, esta limitação pode não ser relevante, uma vez que seu movimento deve consumir uma quantidade muito mais expressiva de energia do que a comunicação. Neste caso, o problema se relaciona à estabilidade dos enlaces, bem como ao curto intervalo de tempo disponível para transmitir e receber dados. Logo, o melhor é comunicar o menos possível. Com relação à interação entre nós sensores estáticos, os problemas de disseminação e alocação de missões de sensoriamento são estudados e uma solução que explora o uso de informações locais é proposta e avaliada. Esta solução emprega agentes de software móveis que têm a capacidade de tomar decisões autônomas através do uso de informações de contexto local. Para redes de sensores móveis, o problema estudado se refere a como transferir missões entre os nós sensores de acordo com seu movimento e localização em relação aos locais onde as missões devem ser executadas. Para tratar este problema, uma abordagem baseada em agentes móveis é proposta, na qual os agentes implementam a migração das missões de sensoriamento usando informações de contexto geográfico para decidir a respeito de suas migrações. Para redes de sensores com sensores estáticos e móveis, a cooperação entre eles é abordada através de um mecanismo com inspiração biológica para realizar a realizar a entrega de dados emitidos pelos sensores estáticos aos sensores móveis. Para isto, explora-se uma analogia baseada no comportamento de formigas na construção e seguimento de trilhas. As soluções propostas são flexíveis, sendo aplicáveis a diferentes domínios de aplicação. Resultados experimentais evidenciam sua escalabilidade, avaliando, por exemplo, seu custo em termos de comunicação, além de outras métricas de interesse para cada uma das soluções. Estes resultados são comparados aos atingidos por soluções de referência (solução ótima teórica e baseada em inundação), indicando sua eficiência. Estes resultados são próximos do ótimo teórico e significativamente melhores que aqueles atingidos por soluções baseadas em técnicas de inundação.
Surveillance systems are usually employed to monitor wide areas in which their users are interested in detecting and/or observing events or phenomena of their interest. The use of wireless sensor networks in such systems is of particular interest as these networks can provide a relative low cost and robust solution to cover large areas. Emerging applications in this context are proposing the use of wireless sensor networks composed of both static and mobile sensor nodes. Motivation for this trend is to reduce deployment and operating costs, besides providing enhanced functionalities. This work focuses on the proposal of solutions for wireless sensor networks including static and mobile sensor nodes specifically regarding cooperative and context aware mission setup and performance. The goal is to keep the communication costs as low as possible in the execution of the proposed solutions. This concern comes from the fact that communication increases energy consumption, which is a particular issue for energy constrained sensor nodes often used in wireless sensor networks, especially if battery supplied. In the case of the mobile nodes, this energy constraint may not be valid, since their motion might need much more energy, but links instabilities and short time windows available to receive and transmit data. Therefore, it is better to communicate as little as possible. For the interaction among static sensor nodes, the problems of dissemination and allocation of sensing missions are studied and a solution that explores local information is proposed and evaluated. This solution uses mobile software agents that have capabilities to take autonomous decisions about the mission dissemination and allocation using local context information. For mobile wireless sensor networks, the problem studied is how to perform handover of missions among the nodes according to their movements and locations in relation to the place where the missions have to be performed. To handle this problem, a mobile agent approach is proposed in which the agents implement the sensing missions’ migration from node to node using geographical context information to decide about their migrations. For the networks combining static and mobile sensor nodes, the cooperation among them is approached by a biologically-inspired mechanism to deliver data from the static to the mobile nodes. The data delivery mechanism explores an analogy based on the behaviour of ants building and following trails, inspired by the ant colony algorithm. The proposed solutions are flexible, being able to be applied to different application domains. Obtained experimental results provide evidence of the scalability of these proposed solutions, for example by evaluating their cost in terms of communication, among other metrics of interest for each solution. These results are compared to those achieved by reference solutions (theoretical optimum and floodingbased), providing indications of the proposed solutions’ efficiency. These results are considered close to the theoretical optimum one and significantly better than the ones achieved by flooding-based solutions.

El funcionament del cervell es basa en processos complexos, que encara no s’han descrit i comprès detalladament. En les últimes dècades, la neurociència ha experimentat un desenvolupament accelerat, impulsat per noves neurotecnologías que permeten monitoritzar les dinàmiques de l’activitat elèctrica al cervell amb una major resolució espai-temporal i una àrea de cobertura més àmplia. No obstant això, a causa de l’alta complexitat de les xarxes neuronals al cervell, que són compostes per poblacions neuronals fortament interconnectades en àmplies regions cerebrals, estem lluny de detectar una fracció significativa de les neurones que donen lloc a funcions complexes. Per tal d’investigar les dinàmiques neuronals a gran escala amb alta resolució espacial, s’han utilitzat diverses tecnologies, que inclouen la ressonància magnética funcional (fMRI), imatges amb marcadors sensibles al voltatge o registres electrofisiològics d’alt recompte de sensors. No obstant això, la resolució temporal del fMRI i els mètodes òptics es limita típicament a uns pocs hertzs, gairebé tres ordres de magnitud per sota de la dels potencials d’acció, i es limiten a les condicions en què el subjecte es troba immòbil. D’altra banda, els registres electrofisiològics basats en matrius de microelèctrodes proporcionen una alta resolució espai-temporal, el que permet detectar amb precisió dinàmiques ràpides de centenars de neurones individuals simultàniament en animals que es mouen lliurement. No obstant això, les interfícies de detecció neuroelectrónica presenten una limitació en el producte entre la resolució espacial i l’àrea de cobertura. A més, presenten una baixa sensibilitat a la banda de freqüència infra-lenta (<0.5Hz), que està relacionada amb la connectivitat funcional de llarg abast. En aquesta tesi es presenta una nova tecnologia basada en sensors actius de grafè, que permet incrementar l’àrea de cobertura i la resolució espacial dels registres electrofisiològics conservant una alta sensibilitat en una banda de freqüència àmplia, des de l’activitat infra-lenta fins a la de una sola cèl·lula electrogénica. Aquest desenvolupament tecnològic es divideix en tres etapes principals; en primer lloc, s’obté una comprensió més profunda de les característiques intrínseques del soroll i la resposta en freqüència d’aquests sensors basant-se en l’estat de l’art en tecnologia de sensors de grafè. En la segona etapa, es mostra un sistema quasi-comercial basat en matrius de sensors de grafè epi-cortical i transmissió sense fil per a la implantació crònica en rates. Amb aquest sistema, es demostra la reproductibilitat de les matrius de sensors de grafè, la seva estabilitat a llarg termini i la seva biocompatibilitat crònica. A més, es proporciona evidència preliminar per a una àmplia gamma de nous patrons electrofisiològics gràcies a la seva sensibilitat en la banda de freqüència infra-lenta. Finalment, en l’última etapa d’aquesta tesi, l’enfocament se centra en el desenvolupament de noves estratègies de multiplexació per augmentar el nombre de sensors a les sondes neuronals. Aquestes tres etapes principals de desenvolupament han portat a la demostració del potencial de les matrius de sensors de grafè multiplexats per al mapejat de les dinàmiques neuronals a gran escala en una banda de freqüència àmplia, en animals que es mouen lliurement, durant llargs períodes. La combinació d’aquestes capacitats fa que les matrius de sensors actius de grafè siguin una tecnologia prometedora per a interfícies cervell-ordinador d’alt ample de banda i una eina única per investigar el paper de l’activitat infra-lenta en la coordinació de les dinàmiques neuronals d’alta freqüència.
El funcionamiento del cerebro se basa en procesos complejos, que aún no se han descrito y comprendido detalladamente. En las últimas décadas, la neurociencia ha experimentado un desarrollo acelerado, impulsado por nuevas neurotecnologías que permiten monitorear la dinámica de la actividad eléctrica en el cerebro con una mayor resolución espacio-temporal y un área de cobertura más amplia. Sin embargo, debido a la alta complejidad de las redes neuronales en el cerebro, que están compuestas por poblaciones neuronales fuertemente interconectadas en amplias regiones cerebrales, estamos lejos de monitorear una fracción significativa de neuronas que dan lugar a funciones complejas. Con el fin de investigar las dinámica neuronales a gran escala con alta resolución espacial, se han utilizado diversas tecnologías, que incluyen la resonancia magnética funcional (fMRI), imágenes con marcadores sensibles al voltaje o registros electrofisiológicos de alto conteo de sensores. Sin embargo, la resolución temporal del fMRI y los métodos ópticos se limita típicamente a unos pocos hercios, casi tres órdenes de magnitud por debajo de la de los potenciales de acción, y se limitan a condiciones en los que el sujeto se encuentra inmóvil. Por otro lado, los registros electrofisiológicos basados en matrices de microelectrodos proporcionan una alta resolución espacio-temporal, lo que permite detectar con precisión dinámicas rápidas de cientos de neuronas individuales simultáneamente en animales que se mueven libremente. Sin embargo, las interfaces de detección neuroelectrónica presentan una limitación en el producto entre la resolución espacial y el área de cobertura. Además, presentan una baja sensibilidad en la banda de frecuencia infra-lenta (<0.5Hz), que está relacionada con la conectividad funcional de largo alcance. En esta tesis se presenta una nueva tecnología basada en sensores activos de grafeno, que permite incrementar el área de cobertura y la resolución espacial de los registros electrofisiológicos conservando una alta sensibilidad en una amplia banda de frecuencia, desde la actividad infra-lenta hasta la de una sola célula electrogénica. Este desarrollo tecnológico se divide en tres etapas principales; en primer lugar, se obtiene una comprensión más profunda de las características intrínsecas del ruido y la respuesta en frecuencia de estos sensores basándose en el estado del arte en tecnología de sensores de grafeno. En la segunda etapa, se muestra un sistema cuasi-comercial basado en matrices de sensores de grafeno epi-cortical y transmisión inalámbrica para implantación crónica en ratas. Con este sistema, se demuestra la reproducibilidad de las matrices de sensores de grafeno, su estabilidad a largo plazo y su biocompatibilidad crónica. Además, se proporciona evidencia preliminar para una amplia gama de nuevos patrones electrofisiológicos debido a su sensibilidad en la banda de frecuencia infra-lenta. Finalmente, en la última etapa de esta tesis, el enfoque se centra en el desarrollo de nuevas estrategias de multiplexación para aumentar el número de sensores en las sondas neuronales. Estas tres etapas principales de desarrollo han llevado a la demostración del potencial de las matrices de sensores de grafeno multiplexados para el mapeado de las dinámicas neuronales a gran escala en una amplia banda de frecuencia en animales que se mueven libremente durante largos períodos. La combinación de estas capacidades hace que las matrices de sensores activos de grafeno sean una tecnología prometedora para interfaces cerebro-ordenador de alto ancho de banda y una herramienta única para investigar el papel de la actividad infra-lenta en la coordinación de las dinámicas neuronales de alta frecuencia.
Brain function is based on highly complex processes, which remain yet to be described and understood in detail. In the last decades, neuroscience has experienced an accelerated development, prompted by novel neurotechnologies that allow monitoring the dynamics of electrical activity in the brain with a higher spatio-temporal resolution and wider coverage area. However, due to the high complexity of neural networks in the brain, which are composed of strongly interconnected neural populations across large brain regions, we are far from monitoring a significant fraction of neurons mediating complex functions. In order to investigate large-scale brain dynamics with high spatial resolution several technologies have been extensively used, including functional magnetic resonance imaging (fMRI), voltage-sensitive dye imaging or high sensor-count electrophysiological recordings. However, the temporal resolution of fMRI and optical methods is typically limited to few hertz, almost three orders of magnitude below that of action potentials, and are limited to head-fixed conditions. On the other hand, electrophysiological recordings based on micro-electrode arrays provide a high spatio-temporal resolution, allowing to accurately detect fast dynamics from hundreds of individual neurons simultaneously in freely moving animals. However, neuroelectronic sensing interfaces present a trade-off between spatial resolution and coverage area. Moreover, they present a poor sensitivity in the infra-slow frequency band ($<0.5$\,$Hz$), which is related to long-range functional connectivity. In this thesis, a novel technology based on graphene active sensors is presented, which allows to increase the coverage area and spatial resolution of electrophysiological recordings while preserving a high sensitivity in a wide frequency band, from infra-slow to single electrogenic cell activity. This technological development is divided into three main stages; first, a deeper understanding of the intrinsic noise characteristics and frequency response of these sensors is obtained by building on prior graphene sensor technology. In the second stage, a quasi-commercial system based on epi-cortical graphene sensor arrays and a wireless headstage for chronic implantation in rats is shown. Using this system, the reproducibility of the graphene sensor arrays, their long-term stability and their chronic biocompatibility are demonstrated. Furthermore, preliminary evidence is provided for a wide range of novel electrophysiological patterns owing to their sensitivity in the infra-slow frequency band. Finally, in the last stage of this thesis, the focus is centred on the development of new multiplexing strategies to upscale the number of sensors on the neural probes. These three main development stages have led to the demonstration of the potential of multiplexed graphene sensor arrays for mapping of large-scale brain dynamics in a wide frequency band in freely moving animals over long periods. The combination of these capabilities makes graphene active sensor arrays a promising technology for high bandwidth brain computer interfaces and a unique tool to investigate the role of infra-slow activity on the coordination of higher frequency brain dynamics.
Universitat Autònoma de Barcelona. Programa de Doctorat en Enginyeria Electrònica i de Telecomunicació

Aquesta tesi aborda el problema de trobar solucions confortables, de baixa potència i sense fils per aplicacions mèdiques. La tesi tracta els avantatges i les limitacions de tres tecnologies de comunicació diferents per la mesura de paràmetres del cos i mètodes per redissenyar sensors per avaluacions òptimes centrades en el cos. La tecnologia RFID es considera una de les solucions més influents per superar el problema del consum d'energia limitat, a causa de la presència de molts sensors connectats. També s'ha estudiat la tecnologia Bluetooth de baixa energia per resoldre els problemes de seguretat i la distància de lectura que, en general, representen el coll d'ampolla de RFID pels sensors de cos. Els dispositius analògics poden reduir dràsticament les necessitats d'energia a causa dels sensors i les comunicacions, considerant pocs elements i un mètode de transmissió simple. S'estudia un mètode de comunicació completament passiu, basat en FSS, que permet una distància de lectura raonable amb capacitats de detecció precises i confiables, que s'ha discutit en aquesta tesi. L'objectiu d'aquesta tesi és investigar múltiples tecnologies sense fils per dispositius portàtils per identificar solucions adequades per aplicacions particulars en el camp mèdic. El primer objectiu és demostrar la facilitat d'ús de les tecnologies econòmiques sense bateria com un indicador útil de paràmetres fisiopatològics mitjançant la investigació de les propietats de les etiquetes RFID. A més a més, s'ha abordat un aspecte més complex respecte a l'ús de petits components passius com sensors sense fils per trastorns del son. Per últim, un altre objectiu de la tesi és el desenvolupament d'un sistema completament autònom que utilitzi tecnologia BLE per obtenir propietats avançades mantenint baix tant el consum com el preu
Esta tesis aborda el problema de encontrar soluciones confortables, inalámbricas y de baja potencia para aplicaciones médicas. La tesis discute las ventajas y limitaciones de tres tecnologías de comunicación diferentes para la medición en el cuerpo y los métodos para elegir y remodelar los sensores para evaluaciones óptimas centradas en el cuerpo. La tecnología RFID se considera una de las soluciones más influyentes para superar el consumo de energía limitado debido a la presencia de muchos sensores conectados. Además, la baja energía de Bluetooth se ha estudiado se ha estudiado la tecnologia Bluetooth de baja energia para resolver los problemas de seguridad y la distancia de lectura que, en general, representan el cuello de botella de la RFID para los sensores de cuerpo. Los dispositivos analógicos pueden reducir drásticamente las necesidades de energía debido a los sensores y las comunicaciones, considerando pocos elementos y un método de transmisión simple. Se estudia un método de comunicación completamente pasivo, basado en FSS, que permite una distancia de lectura razonable con capacidades de detección precisas y confiables, que se ha discutido en esta tesis. El objetivo de esta tesis es investigar múltiples tecnologías inalámbricas para dispositivos portátiles para identificar soluciones adecuadas para aplicaciones particulares en campos médicos. El primer objetivo es demostrar la facilidad de uso de las tecnologías económicas sin batería como un indicador útil de dichos parámetros fisiopatológicos mediante la investigación de las propiedades de las etiquetas RFID. Además, se ha abordado un aspecto más complejo con respecto al uso de pequeños componentes pasivos como sensores inalámbricos para enfermedades del sueño. Por último, un resultado de la tesis es desarrollar un sistema completamente autónomo que utilice la tecnología BLE para obtener propiedades avanzadas que mantengan la baja potencia y un precio bajo.
This thesis addresses the problem of comfortable, low powered and, wireless solutions for specific body-worn sensing. The thesis discusses advantages and limitations of three different communication technologies for on body measurement and investigate methods to reshape sensors for optimum body-centric assessments. The RFID technology is considered one of the most influential solutions to overcome the limitated power consumption due to the presence of many sensors connected. Further, the Bluetooth low energy has been studied to solve security problems and reading distance that overall represent the bottleneck of the RFID for the body-worn sensors. Analog devices can drastically reduce the energy needs due to the sensors and the communications, considering few elements and a simple transmitting method. An entirely passive communication method, based on FSS is studied, enabling a reasonable reading distance with precise and reliable sensing capabilities, which has been discussed in this thesis. The objective of this thesis is to investigate multiple wireless technologies for wearable devices to identify suitable solutions for particular applications in medical fields. The first objective is to demonstrate the usability of the inexpensive battery-less technologies as a useful indicator of such a physio-pathological parameters by investigating the properties of the RFID tags. Furthermore, a more complex aspect regards the use of small passive components as wireless sensors for sleep diseases has been addressed. Lastly, an outcome of the thesis is to develop an entirely autonomous system using the BLE technology to obtain advanced properties keeping low power and a low price.

A context-aware computing system is one that can deduce the state of its surroundings using input from sensors and can change its behaviour accordingly. Context-aware devices might personalise themselves to their current user, alter their functionality based on where they were being used, or take advantage of nearby computing and communications resources. Location-aware systems, whose behaviour is determined by the positions of objects in the environment, represent a practical subset of the context-aware computing paradigm, and several systems of this nature have already been demonstrated. The location sensors used by those systems, however, report the positions of objects to only a room-scale granularity, limiting the extent to which devices and applications can adapt to their surroundings. Sensor technologies that can provide more detailed information about the locations of objects must therefore be investigated. This dissertation describes a new ultrasonic location sensor, which may be deployed in indoor environments such as offices and homes. The sensor can provide fine-grain , three-dimensional position and orientation information, and its characteristics are well suited to the demands of location-aware computing- the sensor is simple, low-powered and unobtrusive. Furthermore, the location system is scalable, in both the number of objects that it can track and the volume within which they may be monitored. A thorough assessment of the sensor's performance is presented in the dissertation, so that location-aware applications can be tailored to its properties. Subsequently, a software architecture that can efficiently distribute finegrain location information to applications is described. The software system provides support for the types of query that will be made frequently by location-aware applications, such as those concerning the spatial relationships between objects and their proximity to one another. The dissertation concludes by examining the use of the ultrasonic location sensor and software architecture to implement a set of novel location-aware applications.

ITC/USA 2008 Conference Proceedings / The Forty-Fourth Annual International Telemetering Conference and Technical Exhibition / October 27-30, 2008 / Town and Country Resort & Convention Center, San Diego, California
This paper explains the development of a wireless network system implemented to streamline grocery store checkout procedures. The design employs a wireless telemetry network consisting of a base station and wireless motes (Micaz MPR2400) that will be located on certain aisles, and attached to shopping carts. This system allows customers to scan items while they shop and uses cashiers for payment purposes only. The objective is to minimize the amount of processing performed by cashiers in order to reduce waiting times in line. The system was tested in a simulation environment and waiting times were reduced by 65%.

Optical fiber sensor multiplexing reduces cost per sensor by designing a system that minimizes the expensive system components (sources, spectrometers, etc.) needed for a set number of sensors. The market for multiplexed optical sensors is growing as fiberoptic sensors are finding application in automated factories, mines, offshore platforms, air, sea, land, and space vehicles, energy distribution systems, medical patient surveillance systems, etc. Optical path length multiplexing (OPLM) is a modification to traditional white-light interferometry techniques to multiplex extrinsic Fabry-Perot interferometers and optical path length two-mode sensors. Additionally, OPLM techniques can be used to design an optical fiber sensor to detect pressure/force/acceleration and temperature simultaneously at a single point. While power losses and operating range restrictions limit the broadscale applicability of OPLM, it provides a way to easily double or quadruple the number of sensors by modifying the demodulation algorithm. The exciting aspect of OPLM is that no additional hardware is needed to multiplex a few sensors. In this way OPLM works with conventional technology and algorithms to drastically increase their efficiency. [1]
Master of Science

Esta tese apresenta os estudos e esforços visando ao desenvolvimento de sensores químicos para aplicações diversas na área forense. Foram desenvolvidos métodos eletroanalíticos para detecção e quantificação de alguns compostos comumente encontrados na adulteração de amostras de drogas de abuso (procaína, fenacetina, aminopirina, paracetamol, levamisol), além da cocaína e estudos fundamentais sobre o comportamento eletroquímico desses compostos. Empregaram-se também métodos eletroquímicos para quantificação de compostos tóxicos e perigosos como explosivos (ácido pícrico) e melamina por exemplo. Os trabalhos utilizando sensores eletroquímicos contemplam modificações eletroquímicas das superfícies eletródicas, utilização de sensores com polímeros molecularmentes impressos (MIP) e eletrodos descartáveis em papel utilizando diferentes técnicas voltamétricas e amperométricas, eletrodo disco rotatório (EDR) e microbalança de cristal de quartzo. Além da fabricação de dispositivos analíticos descartáveis em papel empregando detecção eletroquímica utilizou-se também a detecção colorimétrica para quantificação de alguns dos principais adulterantes de amostras de apreensão de cocaína, como procaína e fenacetina, bem como análises e discriminações de compostos explosivos (peroxi e nitro compostos) nessas plataformas portáteis e de baixo custo. Os métodos foram sempre desenvolvidos visando característicos como: facilidade, praticidade, baixo custo e portabilidade para análises diretamente no local de medida com mínima infraestrutura laboratorial. Por fim, são apresentados alguns estudos realizados durante estágio de pesquisa no exterior (Universidade da Califórnia - San Diego (UCSD)) na área de Wearable Sensors, em que foram desenvolvidos métodos para análises de micronutrientes no suor (zinco) e um metabólito (ácido úrico) na saliva usando sensores aplicados diretamente no corpo humano.
This thesis shows studies and efforts to the development of chemical sensors for different applications in the forensic field. Electroanalytical methods were developed for detection and quantification of some compounds (procaine, phenacetin, aminopyrine, acetaminophen, levamisole) commonly found in the drug of abuse adulteration process and cocaine, as well as, fundamental studies about the electrochemical behavior of these compounds. It was also employed electrochemical methods for quantification of hazardous compounds such as explosives (picric acid) and melamine. Analytical methods with electrochemical sensors included electrochemical modification of electrodic surfaces, molecularly imprinted polymers (MIP), and paper disposable electrochemical devices using different voltammetric and amperometric techniques, rotating disc electrode (RDE) and quartz crystal microbalance. In addition to the fabrication of paper disposable analytical devices with electrochemical detection, it was also used the colorimetric detection to quantify some of the major adulterants in cocaine seizure samples, such as procaine and phenacetin, as well as analysis and discrimination of explosive compounds (peroxy and nitro explosives) in these low cost portable platforms. All proposed methods were always developed aming at theses characteristics: ease, convenience, low cost and portability for analysis directly at the measurement site with minimal laboratory infrastructure. Finally, we presented some studies conducted during research internship abroad (University of California - San Diego (UCSD)) in the area of Wearable Sensors, which have been developed methods for micronutrient analysis in sweat (Zn) and a metabolite (Uric Acid) in saliva using sensors applied directly to the human body

Mapping is one of the main components of autonomous robots, and consist in the construction of a model of their environment based on the information gathered by different sensors over time. Those maps will have different attributes depending on the type of sensor used for the reconstruction. In this thesis we focus on RGBD cameras and LiDARs. The acquired data with cameras is dense, but the range is short and the construction of large scale and consistent maps is more challenging. LiDARs are the exact opposite, they give sparse data but can measure long ranges accurately and therefore support large scale mapping better. The thesis presents a method that uses both types of sensors with the purpose of combine their strengths and reduce their weaknesses. The evaluation of the system is done in an indoor environment, and with an autonomous robot. The result of the thesis shows a map that is robust in large environments and has dense information of the surroundings.
Kartläggning är en av huvudkomponenterna för autonoma robotar, och består av att bygga en modell av miljön utifrån informationen som samlats in av olika sensorer över tid. Dessa kartor kommer att ha olika attribut beroende på vilken typ av sensor som används för rekonstruktionen. I denna avhandling är fokus på RGBD-kameror och LiDARs. Datan från kameror är kompakt men kan bara mäta korta sträckor och det är utmanande att konstruera storskaliga och konsistenta kartor. LiDARs är exakt motsatta, de ger gles data men kan mäta långa avstånd noggrant och stödjer därför storskalig kartering bättre. Avhandlingen presenterar en metod som använder båda typerna av sensorer i syfte att kombinera deras styrkor och minska svagheterna. Utvärderingen av systemet sker i en inomhusmiljö och med en autonom robot. Resultatet av avhandlingen visar en karta som är robust i stora miljöer och har tät information om omgivningen.

Los dispositivos ‘Organ-On-a-Chip' han revolucionado la forma de conocer la biología que hasta el momento se ha venido realizando con los cultivos celulares. Estos sistemas, que contemplan el co-cultivo en tres dimensiones y tecnología microfluídica, tienen como propósito mimetizar la fisiología humana con sistemas de cultivo in-vitro. Su finalidad es la de incrementar el conocimiento de los procesos biológicos, así como también de disponer de una herramienta de diagnóstico efectiva para el análisis de diferentes fármacos. A medida que aumenta la complejidad biológica de los sistemas de cultivo, la necesidad de analizar y monitorizar su respuesta también aumenta. En la actualidad, el análisis de los sistemas 'Organ-On-a-Chip' se basa principalmente en métodos analíticos convencionales que en la mayoría de casos implica la muerte del cultivo celular, la alteración del sistema microfluídico para la recolección de muestras, la imposibilidad de hacer análisis en tiempo real e incluso el aumento del coste y la complejidad del sistema en su conjunto. Es en este contexto en el que esta tesis intenta desarrollar herramientas para la monitorización de parámetros celulares en tiempo real en sistemas 'Organ-On-a-Chip', ya que se han convertido en una valiosa estrategia para la comprensión de los procesos biológicos complejos que ocurren. Se proponen dos estrategias que no comprometen el funcionamiento del sistema 'Organ-On-a-Chip' como tal. Una de ellas tiene por objetivo monitorizar parámetros físicos de forma externa al sistema de cultivo, usando plataformas modulares que incorporan varios sensores y que pueden ser conectadas en línea con el sistema microfluídico sin intervenir en su funcionamiento. En concreto, se han integrado sensores electroquímicos miniaturizados en un sustrato plástico usando técnicas convencionales de microfabricación y prototipaje rápido, para la medición simultánea de los parámetros de oxígeno disuelto e iones Na+, K+ y pH. La otra estrategia desarrollada en esta tesis va un paso más allá, dado que integra los sensores dentro del mismo sistema 'Organ-On-a-Chip', embebiéndolos en la propia membrana donde se realiza el cultivo celular. El reto consiste en integrar sensores de bajo coste de manera eficiente, en una membrana flexible, muy porosa y delgada. Esto es posible gracias al uso de la tecnología de impresión por inyección de tinta como alternativa a las costosas tecnologías de microfabricación convencionales. Específicamente, se han incorporado y validado sensores electroquímicos de oxígeno disuelto en un sistema real de 'Liver-On-a-Chip' que permite monitorizar el consumo de oxígeno de un cultivo de células epiteliales renales en tiempo real. Ambos son planteamientos válidos, y la elección de uno de ellos dependerá del interés biológico que puede tener realizar mediciones externas o internas al sistema de cultivo, y del grado de complejidad tecnológico que ello implique.
Organ-On-a-Chip devices have changed the way to know the biology being indispensable in the evolution and understanding of the cell culture systems. Organ-On-a-Chip systems are based in three-dimensional microfluidic co-culture models and their purpose is to reproduce a real microenvironment in order to mimic human pathophysiology using in-vitro multicellular models. Their finality is to increase the understanding of the biological processes as well as to develop improved diagnostics and more effective tools for drug screening analysis. As the biological complexity of the cell cultures under investigation increases, the need to analyze and monitor cell culture response also increases. Currently, analysis of Organ-On-a-Chip cell cultures still mainly relies on conventional analytical methods which in most cases involve the death of the cell culture, the disturbance of the microfluidic system for sample collection, the impossibility to observe real-time events, or even the increase of the cost and the complexity of the whole systems. In this context, this thesis work is focused on the development of monitoring tools to allow the analysis of Organ-On-a-Chip parameters in real-time, becoming a valuable strategy for understanding complex biological processes. Two proposed strategies have been addressed for the real-time monitoring without compromising the operation of the system. The first deals with the monitoring of physical parameters externally to an Organ-On-a-Chip systems, using modular sensing platforms connected in-line with the microfluidic system without disturbing it. For this purpose, miniaturized electrochemical sensors have been integrated in a plastic substrate using conventional microfabrication and rapid-prototyping techniques, for the simultaneous measurement of dissolved oxygen, Na+, K+ and pH parameters. The other strategy developed in this thesis goes one step further, with the integration of the sensors inside the Organ-On-a-Chip, embedded in the cell culture membrane. The challenge is to integrate efficiently and cost-effectively the sensors in a high porous and very thin and flexible membrane without damaging it. This is possible because inkjet printing technology is selected as an alternative to the conventional microfabrication technologies due to their digital material deposition without any direct contact with the membrane. Specifically, an array of electrochemical dissolved oxygen sensors have been implemented and validated in a real Liver-on-a-chip system using rat and human epithelial cells. Both proposed strategies are valid approaches, and the choice of one of them is depending on the biological interest, their interest in measuring parameters externally or inside the cell culture system, and the degree of technological complexity involved.

The lack of passive, wireless, chemical and biological sensor systems is a significant impediment to sensor system applications. While active sensors with a wireless communications link continue to decrease in power consumption, they still require a power source, such as a battery. This active power consumption limits the useful life of the sensor and its applications. A more attractive solution would be a passive, wireless, chemical and biological sensor integrated with a wireless interrogation platform to monitor the sensor. The focus of this thesis is the realization of a wireless sensor interrogator capable of monitoring multiple, passive, resonant-frequency sensors. It is demonstrated, using Frequency Modulation Spectroscopy techniques, that the resonant frequency of a passive sensor can be detected and tracked over time. Simulated results are presented that verify the functionality of the proposed wireless sensor interrogator. In addition, an experimental hardware setup and subsequent experimental results are presented that verify the simulation results. Considerations for the design of the wireless sensor interrogator and opportunities for future research are discussed.

This research investigates the current structure of the Ministry of Defence's procurement system, with particular emphasis on the procurement of military sensor systems. A lifecycle common test environment, with an appropriate commercial construct for its implementation, is proposed. Sensor systems include radar, passive RF surveillance (ESM) as well as electro-optic, infrared, sonar and other acoustic monitoring systems that are used to gather intelligence for a number of purposes including 1. Pre-empting hostile acts 2. Reducing risk to friendly forces and non-combatants in danger zones 3. Informing and prosecuting attacks on hostile forces Sensor systems often form part of larger systems, also called systems of systems. In some cases, a number of sensors are required to work together to improve information extraction by data or information fusion. It will be seen that these are complex systems. They are often designed to adapt their modes of operation to meet evolving situations. In this way, they can optimise themselves to meet their deployment objectives. These are difficult systems to specify. Therefore, they are difficult systems to test; they are expected to respond to a large number of situations that cannot easily be defined in advance of their being encountered. This research brings together technical and commercial initiatives to remove many of the existing discontinuities along the lifecycle of such projects. The discontinuities harbour technical and commercial discrepancies that detract from achieving delivery and cost targets. A pragmatic Test and Evaluation concept is defined. It is backed by a commercial process. Together they provide an independent way to deliver continuous lifecycle evaluation and test of sensor systems. This research offers a quantifiable measure of military capability improvements that complies with Systems Engineering and Management good practice.