Tesi sul tema "Multiparameter and Wireless measurement"

Les machines électriques de forte puissance sont soumises à des contraintes mécaniques, thermiques et magnétiques sévères en fonctionnement. Pour assurer leur fiabilité et la continuité de leur opération, il est crucial de disposer d'informations en temps réel sur ces contraintes, souvent à l'échelle locale. Les technologies de capteurs sans fil et sans batterie, combinées à des techniques efficaces d'analyse des données et de traitement des signaux, sont indispensables pour répondre à ce besoin. Les ondes acoustiques de surface permettent de concevoir des capteurs sans fil et totalement passifs, capables de mesurer de nombreuses grandeurs physiques telles que la température, les contraintes mécaniques et le champ magnétique, grâce à une ingénierie avancée du design. Le travail réalisé dans cette thèse a permis de développer des capteurs SAW multi-grandeurs pour la mesure des déformations, de la température et du champ magnétique. Ces capteurs ont d'abord été calibrés sur des bancs d'essais en laboratoire, puis utilisés pour caractériser les propriétés mécaniques, telles que la magnétostriction, et les propriétés magnétiques, telles que les pertes magnétiques, des tôles ferromagnétiques employées dans la conception des machines électriques de forte puissance. La caractérisation des propriétés des tôles ferromagnétiques est cruciale pour plusieurs raisons : concevoir des systèmes électromagnétiques efficaces, minimiser les vibrations et les bruits indésirables, contrôler la dissipation d'énergie, prévenir la fatigue des matériaux, optimiser la conception des composants pour l'efficacité énergétique et développer des composants résistants à la chaleur pour la fiabilité et la durabilité... Le projet de thèse implique l'entreprise JEUMONT Electric (société de haute technologie spécialisée dans les solutions de conversion d'énergie), le groupe AIMAN-FILMS de l’IEMN et l'équipe Outils et Méthodes Numériques du L2EP. Chaque partenaire apporte des compétences spécifiques pour aborder l'instrumentation multi-physique des machines électriques de forte puissance
High-power electrical machines are subjected to severe mechanical, thermal, and magnetic stresses during operation. To ensure their reliability and continuous operation, it is crucial to have real-time information on these constraints, often at a local scale. Wireless and battery-free sensor technologies, combined with effective data analysis and signal processing techniques, are essential to meet this need. Surface acoustic waves (SAW) allow the design of wireless and completely passive sensors capable of measuring various physical quantities such as temperature, mechanical stress, and magnetic fields, thanks to advanced design engineering. The work carried out in this thesis has enabled the development of multi-quantity SAW sensors for measuring deformations, temperature, and magnetic fields. These sensors were first calibrated on laboratory test benches and then used to characterize the mechanical properties, such as magnetostriction, and magnetic properties, such as magnetic losses, of ferromagnetic sheets used in the design of high-power electrical machines. Characterizing the properties of ferromagnetic sheets is crucial for several reasons: designing efficient electromagnetic systems, minimizing vibrations and unwanted noise, controlling energy dissipation, preventing material fatigue, optimizing component design for energy efficiency, and developing heat-resistant components for reliability and durability. The thesis project involves JEUMONT Electric (a high-tech company specializing in energy conversion solutions), the AIMAN-FILMS group from IEMN, and the Numerical Tools and Methods team from L2EP. Each partner brings specific expertise to address the multi-physical instrumentation of high-power electrical machines

Performance Measurement of the IP packet networks mainly comprise of monitoring the network performance in terms of packet losses and delays. If used appropriately, these network parameters (i.e. delay, loss and bandwidth etc) can indicate the performance status of the network and they can be used in fault and performance monitoring, network provisioning, and traffic engineering. Globally, there is a growing need for accurate network measurement to support the commercial use of IP networks. In wireless networks, transmission losses and communication delays strongly affect the performance of the network. Compared to wired networks, wireless networks experience higher levels of data dropouts, and corruption due to issues of channel fading, noise, interference and mobility. Performance monitoring is a vital element in the commercial future of broadband packet networking and the ability to guarantee quality of service in such networks is implicit in Service Level Agreements. Active measurements are performed by injecting probes, and this is widely used to determine the end to end performance. End to end delay in wired networks has been extensively investigated, and in this thesis we report on the accuracy achieved by probing for end to end delay over a wireless scenario. We have compared two probing techniques i.e. Periodic and Poisson probing, and estimated the absolute error for both. The simulations have been performed for single hop and multi- hop wireless networks. In addition to end to end latency, Active measurements have also been performed for packet loss rate. The simulation based analysis has been tried under different traffic scenarios using Poisson Traffic Models. We have sampled the user traffic using Periodic probing at different rates for single hop and multiple hop wireless scenarios. 5 Active probing becomes critical at higher values of load forcing the network to saturation much earlier. We have evaluated the impact of monitoring overheads on the user traffic, and show that even small amount of probing overhead in a wireless medium can cause large degradation in network performance. Although probing at high rate provides a good estimation of delay distribution of user traffic with large variance yet there is a critical tradeoff between the accuracy of measurement and the packet probing overhead. Our results suggest that active probing is highly affected by probe size, rate, pattern, traffic load, and nature of shared medium, available bandwidth and the burstiness of the traffic.

This licentiate thesis presents an advanced wireless system, built on a single hardware platform, for applications in medicine and health. In order to design a single system, adaptable for different context, an accurate system specification is required. The technical requirements are authenticated by actual tests in the environment where the system is intended to be used. The results of these measurements give an understanding of the possibilities of designing a real system but also acts as a base for deriving the empirical formulas to be used as the basis of the development and verification. In summary, this work has included a larger measurement campaign and a verification of subsystems to support the development of wireless systems on a single hardware platform. This can be used for different measurements in medical healthcare and rescue work. Previous systems for endurance tests have limitations in that they are not adapted to different sizes of mammals and they also have shortcomings in the quantification of data and scalability. The developed system was validated on mice and humans. On mice the measurement parameters was the hormone dopamine and locomotion. For humans it was measured time for given distances. Both validation tests showed high correlation with the respective reference methods. The correlation coefficients of mice between the developed system and the former system ranged from 0.916 to 0.967. In the validation with humans, runners were clocked by the system clock and a manual stop watch. The lowest correlation coefficient was 0.864. Advantages with the developed system is that it is scalable and measures the activity level quantitatively in the unit meters and it can also be used for different sizes of mammals in different environments. In tracking devices for rescue it is important that the transmitted signal can be detected at distances as large as possible. A support in the design work is to simulate path loss. This requires a path loss exponent, which was calculated after the measurement campaign. The results showed that the exponent of the height dependency decreases with antenna height above water. For the frequency 200 MHz, the exponent for the antenna height is 0.4 (vertical polarization) and 1.5 (horizontal polarization). For the distance dependency, the exponent was 3.59 (vertical polarization) and 3.22 (horizontal polarization). The path loss exponent is 2 for both the free space- and the ground reflection model. An antenna’s physical dimension is to a large extent dependent on the lowest frequency. The research’s aim was to reduce the physical size by introducing a resonance frequency. The physical length was from the beginning 0.43 meter given by the lowest frequency used (0.7 GHz) and the antenna was reduced in size to 0.22 meter.

Wireless sensor networks (sensornets) enable distributed sensing, opening up sensing possibilities not previously available. One application of sensornets is online, non-intrusive power transformer monitoring.

Low cost, low power wireless sensors (motes) promise to revolutionize environmental data collection, but are they currently refined enough for widespread use by hydrologists? Their viability as a replacement for traditional data collection techniques was investigated in a 7 ha forested watershed in south-western British Columbia. The watershed included 41 instrument clusters measuring air and soil temperature, humidity, throughfall, soil moisture content, overland flow and groundwater head. The foundation of each cluster was a data box containing a MDA300 data acquisition board and a MICA2 processor board from Crossbow Technologies, Inc.™ that allowed for short range wireless data collection. The 41 motes each recorded data every 15 minutes from July, 2006, to April, 2007. In addition to reporting on the reliability of the motes and sensors during the 10 months deployment, the high spatial and temporal resolution data collected by this study gave the opportunity for many analyses of catchment processes. As soil moisture and throughfall are two influential processes in the exchange of water between the earth and the atmosphere, these were the focus of the data analysis. The first analysis was a resampling experiment on seven different events selected from the full data set. Comparing 100 different subsamples each of 5, 10 and 20 points for throughfall and soil moisture showed if increasing the sample size eventually produced diminishing returns in the ability to reproduce the true catchment mean. With significant differences in prediction ability for both soil moisture and throughfall at times of differing hydrologic activity, this analysis provides further support for the theories of changing moisture states of soil moisture and threshold values for throughfall. The second analysis described how the organization of soil moisture and throughfall changed during a range of weather conditions and timescales. Spatial representation of normalized values and Pearson correlation coefficients showed that there were distinct differences between wet and dry periods for soil moisture and between long and short analysis periods for throughfall.

Wireless Sensor Network (WSN), a collection of “sensor nodes” promises to change the scientist’s approach of gathering the environmental data in various fields. Sensor nodes can be used for non-stop sensing, event detection, location sensing and local control of actuators, this concept gives surety to many latest application areas like agriculture, military, home or factory automation, logistics and so on. Remote surveillance and measurement missions can be performed by using WSNs. The hot research topic now-a-days is to make such networks remotely controllable and adaptive to the environment and mission.

The work carried out in this thesis is the development of a surveillance application using TinyOS/nesC. The purpose of this application is to perform event-detection mission by using any one of the built-in sensor on Mica2 motes as well as a setup protocol is designed to make the WSN remotely controllable and adaptive to the mission. In this thesis, an experimental work is also performed using TinyDB to build up a surveillance system whose purpose is to detect and count the total number of person present at any time in a given room and to view the results at a remote place. Besides these two system applications, a comparative study between TinyDB and nesC is described which concludes that more hardware control can be achieved through nesC which is a more power efficient platform for long-term applications.

Multipath fading is a very common phenomenon in signal transmission over wireless channels. When a signal is transmitted over multipath channels, it is subject to reflection, diffraction and refraction. This results in multiple versions of the same signal to arrive at the receiver, each of which has suffered from various path loss, time-delay, phase shift and often also frequency shift. The latter is a result of Doppler shifts, which is experienced whenever a relative movement between the receiver and transmitter or scatterers is present. The communication environment changes quickly over location or time, thus introducing uncertainties to the channel response. Such channels result in increased system complexity, and the propagation effects need to be identified in order to predict the channel behaviour. Path loss is experienced in all types of radio channels, and its metrics are often determined by empirical path loss models. The path loss effects the mean received signal level, whereas large-scale fading (Shadowing) results in large-scale fluctuations of this received level. These variations are superimposed by the small-scale fluctuations, or small-scale fading, caused by multipath reception and Doppler shifts. Small-scale fading is simulated to gain a better understanding of these effects. In order to observe these effects satisfactory, the whole digital radio communication system chain must be simulated. Simulations are also performed for estimating the data capacity over both mobile and fixed multipath channels, and the resulting capacity of multipath reception exceeds the capacity of a flat channel due to increased received energy. In order to classify the effect of multipath channels on signal transmission, the profile of the channel for a given scenario has to be known, i.e. channel metrics such as the RMS delay spread is essential for a successful radio system design. A multipath channel profile and its RMS delay spread can be derived from a vast number of channel measurements performed for a given scenario. Measurements on the multipath channel impulse response have been performed, RMS delay spread has been calculated, and the procedure of the channel measurement process itself is simulated in Matlab.

If we had detailed wireless local area network (WLAN) coverage maps, both staff and equipment could be used more efficiently, for example, less time would be spent searching for connectivity. In addition, system administrators could understand their WLAN's utilization better, thus enabling better planning for where to install new access points, where to remove access points, where to change the type of antenna, etc. This thesis concerns creating detailed indoor coverage models by using measured network performance - in order to enable both users and administrators to visualize the network coverage. Today a user can only easily know about the access points that they currently hear – in the location where they currently are. Giving the users and administrators access to a model of the entire campus coverage will allow them to understand not only the _local_ coverage, but the patterns of coverage (or lack there of). However, no efficient modeling techniques are currently available for those deploying and operating indoor WLANs. The thesis begins with some general background information and then examines a number of WLAN survey tools; in terms of both their performance and cost. Following this a number of related projects are presented. This background provides the motivation for why a new tool is needed and what functions such a tool should have. Next a site survey of the KTH campus in Kista was conducted using a newly developed survey application. This application was developed to better meet the requirements derived from the missing functionality of existing tools. In addition, developing this application gave the author an opportunity to learn a new objectoriented programming language, i.e. C# and the .NET environment. Learning to use this new environment was essential to building both an easy to use application and collecting the data from the system - the later was often not straight-forward. ne of the key issues after data collection is how to present the collected data to the user and how this varies depending upon the user’s interests and task. An initial representation of the experimental data is presented as a manually painted coverage map overlayed onto a map. Next the thesis examines how to integrate the experimental data using Google’s SketchUp in order to build a 3D model of the WLAN coverage on this campus. Future work related to this thesis should focus on how to automate the collection of data and how to automate the presentation of the resulting experimental data.
Om vi hade tillgång till detaljerade täckningskartor över lokala nätverk (WLAN), skulle både personal och utrustning kunna användas mer ändamålsenligt. Till exempel skulle mindre tid gå åt till att söka täckning. Dessutom skulle systemadministratörer förstå användningen av deras WLAN:s på ett bättre sätt, vilket skulle möjliggöra bättre planering av var nya accesspunkter ska installeras, var accesspunkter ska tas bort, var man ska byta antenntyp, osv. Detta examensarbete handlar om skapande av detaljerade täckningsmodeller för användning inomhus vilka genererats genom att mäta nätverkets styrka – detta för att göra det möjligt för båda användare och administratörer att visualisera nätverkstäckning. Idag kan en användare endast känna till accesspunkter som de just för tillfället hör – på den plats där de för tillfället befinner sig. Att ge användarna och administratörerna tillgång till en modell av täckningen över hela Campus skulle inte bara göra att de uppfattade den lokala täckningen utan hela täckningsmönster (eller avsaknaden därav). Dock finns för tillfället inga ändamålsenliga modelleringstekniker för de som utvecklar och sköter WLAN:s inomhus. Examensarbetet inleds med en del bakgrundsinformation och går därefter in på ett antal metoder för att kartlägga WLAN, både vad gäller prestanda och kostnad. Härefter presenteras ett antal relaterade projekt. Denna bakgrund är till för att motivera varför ett nytt verktyg behövs och vilka funktion ett sådant verktyg borde ha. Efter denna litteratur- och bakgrundsstudie gjordes en kartläggning av KTH Campus i Kista med användning av en nyligen utvecklad applikation. Applikationen togs fram för att på ett bättre sätt uppfylla kraven som följde av saknade funktioner i existerande verktyg. Dessutom gav utvecklingen av applikationen författaren en möjlighet att lära sig objektorienterad programmering med t ex C# och .NET-miljön. Att lära sig att använda denna nya programmeringsmiljö var en nödvändighet för att kunna bygga både en lättanvänd applikation och samla in data från systemet – de senare var oftast inte helt lätt. En av de största svårigheterna efter datainsamlingen var att hitta ett sätta att presentera den insamlade informationen samt hur presentationen ska variera beroende på användaren behov och uppgift. En första presentation av experimentdata presenteras som en manuellt ritad täckningskarta lagd ovanpå en vanlig karta. Nästa steg i examensarbetet är att undersöka hur man ska integrera experimentdata genom att använda Google:s SketchUp för att bygga en 3D-modell av WLAN-täckning på Campus i Kista. Framtida utveckling relaterad till detta examensarbete borde fokusera på hur man ska kunna automatisera datainsamlingen och presentationen av resulterande experimentdata.

Voice over Internet Protocol (VoIP) has become very popular in recent days andbecome the first choice of small to medium companies for voice and data integration inorder to cut down the cost and use the IT resources in much more efficient way. Anotherpopular technology that is ruling the world after the year 2000 is 802.11 wirelessnetworks. The Organization wants to implement the VoIP on the wireless network. Thewireless medium has different nature and requirement than the 802.3 (Ethernet) andspecial consideration take into account while implementing the VoIP over wirelessnetwork.One of the major differences between 802.11 and 802.3 is the bandwidthavailability. When we implement the VoIP over 802.11, we must use the availablebandwidth is an efficient way that the VoIP application use as less bandwidth as possiblewhile retaining the good voice quality. In our project, we evaluated the differentcompression and decompression (CODEC) schemes over the wireless network for VoIP.To conduct this test we used two computers for comparing and evaluatingperformance between different CODEC. One dedicated system is used as Asterisk server,which is open source PBX software that is ready to use for main stream VoIPimplementation. Our main focus was on the end-to-end delay, jitter and packet loss forVoIP transmission for different CODECs under the different circumstances in thewireless network. The study also analyzed the VoIP codec selection based on the MeanOpinion Score (MOS) delivered by the softphone. In the end, we made a comparisonbetween all the proposed CODECs based on all the results and suggested the one Codecthat performs well in wireless network.

Wireless sensor network (WSN) has become a hot topic lately. By using WSN things that previously were difficult or impossible to measure has now become available. One of the main reasons using WSN for monitoring is to save money by cost optimization and/or increase safety by letting the user knowing the physical status of the monitored structure. This thesis considers four main topics, empirical testing of WSN in harsh environments, antenna designs, antenna measurements and radio environment emulation. The WSN has been tested in train environment for monitoring of ball bearings and inside jet engines to monitor strain of blades and temperatures. In total, two investigations have been performed aboard the train wagon and one in the jet engine. The trials have been successful and provide knowledge of the difficulties with practical WSN applications. The key issues for WSN are robust communication, energy management (including scavenging) and physical robustness. For the applications of WSN in harsh environments antennas has to be designed. In the thesis, two antennas has been designed, one for train environment and one for the receiver in the jet engine. In the train environment, a more isotropic radiation pattern is preferable; hence a small dual layered patch antenna is designed. The antenna is at the limit of being electrically small; hence slightly lower radiation efficiency is measured. For the WSN in the jet engine, a directive patch array is designed on an ultra-thin and flexible substrate. The thin substrate of the antenna causes rather lower radiation efficiency. But the antenna fulfils the requirements of being conformal and directive. In reverberation chambers are used to measure antennas, but there are difficulties to provide a realistic radio environment, for example outdoor or on-body. In this thesis, a large reverberation chamber is designed and verified. It enables measurement between 400 MHz and 3 GHz. Also, a sample selection method is designed to provide a post processing possibilities to emulate the radio environment inside the chamber. The method is to select samples from a data set that corresponds to a desired probability density function. The method presented in this thesis is extremely fast but the implementation of the method is left for future research.
WISENET
WiseJet

COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
As Redes locais sem fio (WirelessLAN ou WLAN) surgiram como uma alternativa as redes convencionais com fio (LAN), de uma forma mais flexível, de fácil configuração e boa conectividade em áreas fechadas (prediais) ou abertas (campus). Elas combinam a mobilidade do usuário com sua conexão a rede com taxas de comunicação de até 20 Mbps ou mais, empregando técnicas de espalhamento espectral (salto em frequência - FHSS ou sequência direta - DSSS) ou acesso por modulação de frequências ortogonais - OFDM, nas faixas de frequência de 900 MHz, 2.4 Ghz e 5.7 Ghz. Dependendo da tecnologia, faixa de frequência e ambiente de utilização, o alcance das WLAN pode variar de 30 a 250 metros, ou maiores distâncias com as evoluções deste padrão. O seu projeto requer o modelamento do canal de propagação em ambientes internos . Os métodos de previsão de perda de transmissão mais utilizados são de natureza semi-empírica, devido à complexidade do problema em que envolve múltiplos mecanismos de propagação como reflexão em paredes, pisos e tetos, difração em obstáculos e transmissão através de paredes e pisos. Além da perda de propagação deve ser considerado o problema do multipercursos que produz em espalhamento de retardos, o sinal recebido afetando a qualidade do sistema.
The Wireless Local Area Network (WirelessLAN or WLAN) appeared as an alternative the conventio nal Local Area Network (LAN), in a more flexible way, of easy configuration and good conectividade in closed areas (property) or open areas (campus). They combine user s mobility , his/her network connection with communication taxes of up to 20 Mbps or plus, using spread spectrum techniques (Frequency Hopping - FHSS or Direct Sequence - DSSS) or access for Orthogonais Frequency Division Modulation - OFDM, in frequency range of 900 MHz, 2.4 Ghz and 5.7 Ghz. Depending on the technology, frequency range and us e atmosphere, the reach of WLAN can vary from 30 to 250 meters, or larger distances with the evolutions of this pattern. This project requests the model of the propagation channel in internal atmospheres. The methods of forecast of transmission loss more used are of semi-empiric nature, due to the complexity of the problem in that it involves multiple propagation mechanisms as reflection in walls, floors and roofs, diffraction in obstacles and transmission through walls and floors. Besides the propagation loss it should be considered the problem of the multipath that produces in dispersal of retards, the received sign affecting the quality of the system.

In this thesis, a novel graphene (GN) based electrocardiogram (ECG) sensor is designed, constructed and tested to validate the concept of coating GN, which is a highly electrically conductive material, on Ag substrates of conventional electrodes. The background theory, design, experiments and results for the proposed GN-based ECG sensor are also presented. Due to the attractive electrical and physical characteristics of graphene, a new ECG sensor was investigated by coating GN onto itself. The main focus of this project was to examine the effect of GN on ECG monitoring and to compare its performance with conventional methods. A thorough investigation into GN synthesis on Ag substrate was conducted, which was accompanied by extensive simulation and experimentation. A GN-enabled ECG electrode was characterised by Raman spectroscopy, scanning electron microscopy along with electrical resistivity and conductivity measurements. The results obtained from the GN characteristic experimentation on Raman spectroscopy, detected a 2D peak in the GN-coated electrode, which was not observed with the conventional Ag/AgCl electrode. SEM characterisation also revealed that a GN coating smooths the surface of the electrode and hence, improves the skin-to-electrode contact. Furthermore, a comparison regarding the electrical conductivity calculation was made between the proposed GN-coated electrodes and conventional Ag/AgCl ones. The resistance values obtained were 212.4 Ω and 28.3 Ω for bare and GN-coated electrodes, respectively. That indicates that the electrical conductivity of GN-based electrodes is superior and hence, it is concluded that skin-electrode contact impedance can be lowered by their usage. Additional COMSOL simulation was carried out to observe the effect of an electrical field and surface charge density using GN-coated and conventional Ag/AgCl electrodes on a simplified human skin model. The results demonstrated the effectiveness of the addition of electrical field and surface charge capabilities and hence, coating GN on Ag substrates was validated through this simulation. This novel ECG electrode was tested with various types of electrodes on ten different subjects in order to analyse the obtained ECG signals. The experimental results clearly showed that the proposed GN-based electrode exhibits the best performance in terms of ECG signal quality, detection of critical waves of ECG morphology (P-wave, QRS complex and T-wave), signal-to-noise ratio (SNR) with 27.0 dB and skin-electrode contact impedance (65.82 kΩ at 20 Hz) when compared to those obtained by conventional a Ag/AgCl electrode. Moreover, this proposed GN-based ECG sensor was integrated with core body temperature (CBT) sensor in an ear-based device, which was designed and printed using 3D technology. Subsequently, a finger clipped photoplethysmography (PPG) sensor was integrated with the two-sensors in an Arduino based data acquisition system, which was placed on the subject's arm to enable a wearable multiple physiological measurement system. The physiological information of ECG and CBT was obtained from the ear of the subject, whilst the PPG signal was acquired from the finger. Furthermore, this multiple physiological signal was wirelessly transmitted to the smartphone to achieve continuous and real-time monitoring of physiological signals (ECG, CBT and PPG) on a dedicated app developed using the Java programming language. The proposed system has plenty of room for performance improvement and future development will make it adaptabadaptable, hence being more convenient for the users to implement other applications than at present.

Health care costs have increased over the last decades due to an ageing population. Therefore, research in personal health monitoring (PHM) has increased in response to this. PHM has advantages such as mobility (monitoring of health at work or at home), early detection of health problems enabling preventive health measures and a reduction of health care cost. Human motion analysis, using for example inertial measurement units and pedobarography, is an important subcategory of PHM. Pedobarography (PBG) is the study of pressure fields acting between the plantar surface of the foot and a supporting surface. Gait and posture analysis, prosthetics evaluation and monitoring of recovery from injury or disease are examples of PBG applications. Portable PBG can be performed using force sensing resistors built into the insole inside the shoe. In accordance with this, the research goal for this licentiate thesis is to design, build and evaluate a wireless wearable measurement system based on pedobarography for monitoring of health. In order to fulfil the objectives of the research, literature studies were done and problems with existing in-shoe system solutions were identified. Thus, it was found that further opportunities existed for new designs of PBG systems which take these problems into account. Cross-sectional test case studies were used for validation. The research area is multidisciplinary and encompasses biomedical measurements, electronics and computer science. The main research contributions include design and implementation of a PBG measurement system consisting of commercial off the shelf components, a novel method for selecting measurement samples for weight estimation of carried load during walk, and a novel method for analysing walking intensity using force-time integrals at the toe-off phase of the step. The research results suggest that the new PBG system, in combination with the two novel analysing methods, are suitable for use in wearable systems for monitoring of health. Personal health measurements are done to help decision making related to health. Thus, the future work will strive towards designing different decision support systems.
Kostnaderna för vår hälsovård har ökat de senaste årtiondena på grund av att vi lever allt längre. Till följd av detta har forskning inom personlig hälsomonitorering (PHM) ökat. PHM medför fördelar såsom rörlighet (hälsoövervakning på jobbet och i hemmet), tidig upptäckt av hälsoproblem medför möjlighet till åtgärd i ett tidigt skede samt en minskning av kostnaderna för hälsovård. Analys av människors rörelser, med hjälp av till exempel tröghetsmätare och pedobarografi, är en viktig underkategori inom PHM. Pedobarografi (PBG) är studien av tryckfält som uppstår på grund av krafter som verkar mellan fotens undersida och en uppbärande yta. Analys av gångstil och kroppshållning, utvärdering av proteser samt monitorering av återhämtning från skada eller sjukdom är exempel på tillämpningar av PBG. Portabel PBG kan exempelvis utföras med hjälp av resistiva kraftsensorer implementerade i skors inläggssulor. I överrensstämmelse med detta är målet för forskningen i den här licentiatavhandlingen att designa, bygga och utvärdera ett trådlöst bärbart mätsystem baserat på pedobarografi för övervakning av hälsa. För att uppfylla forskningsmålet utfördes litteraturstudier och problem med existerande skobaserade system identifierades. Tvärsnittsstudier användes vid valideringen. Forskningsområdet är tvärvetenskapligt och omfattar biomedicinska mätningar, elektronik och datavetenskap. De främsta vetenskapliga bidragen inkluderar design och implementering av ett pedobarografiskt mätsystem bestående av öppet tillgängliga komponenter, en ny metod för att välja ut uppmätta värden för uppskattning av vikt av buren last under gång, samt en ny analysmetod för gångintensitet med hjälp av kraft-tidsintegraler i stegets avstampsfas. Forskningsresultaten implicerar att det nya pedobarografisystemet, i kombination med de två nya analysmetoderna, är lämpliga att användas i bärbara system för övervakning av hälsa. Mätningar vid personlig hälsomonitorering utförs för att hjälpa till vid beslutsfattande som rör hälsa. Följaktligen strävar framtida forskning mot design av olika beslutsstödsystem.

Wireless Sensor Networks appear as a technology, which provides the basisfor a broad field of applications, drawing interest in various areas. On theone hand, they appear to allow the next step in computer networks, buildinglarge collections of simple objects, exchanging information with respect totheir environment or their own state. On the other hand, their ability tosense and communicate without a fixed physical infrastructure makes theman attractive technology to be used for measurement systems.Although the interest inWireless Sensor Network research is increasing,and new concepts and applications are being demonstrated, several fundamentalissues remain unsolved. While many of these issues do not requireto be solved for proof-of-concept designs, they are important issues to beaddressed when referring to the long-term operation of these systems. Oneof these issues is the system’s lifetime, which relates to the lifetime of thenodes, upon which the system is composed.This thesis focuses on node lifetime extension based on energy management.While some constraints and results might hold true from a moregeneral perspective, the main application target involves environmental measurementsystems based onWireless Sensor Networks. Lifetime extensionpossibilities, which are the result of application characteristics, by (i) reducingenergy consumption and (ii) utilizing energy harvesting are to be presented.For energy consumption, we show howprecise task scheduling due to nodesynchronization, combined with methods such as duty cycling and powerdomains, can optimize the overall energy use. With reference to the energysupply, the focus lies on solar-based solutions with special attentionplaced on their feasibility at locations with limited solar radiation. Furtherdimensioning of these systems is addressed.It will be shown, that for the presented application scenarios, near-perpetualnode lifetime can be obtained. This is achieved by focusing on efficient resourceusage and by means of a carefully designed energy supply.

A passive wireless sensor is designed, fabricated and tested for the measurement of AC electric field in the vicinity of high voltage apparatus. This sensor is applicable in remote condition monitoring of high voltage apparatus where close distance measurements raises safety hazards for operators. The sensor is designed using a coaxial cavity resonator structure (in TEM mode) capacitively coupled to varactors. The resonance frequency of the sensor shifts corresponding to the capacitance variation of the varactors which in turn is perturbed by the external electric field. The electric field surrounding the apparatus induces a bias voltage over the terminals of the varactors. Therefore, the resonance frequency changes proportional to the inducing external electric field and correspondingly to the medium/high voltage. A printed circuit board on the top of the cavity provides coupling between the cavity and varactors and also between the varactors and the external field produced by the high voltage apparatus. The sensor structure is designed to resonate in the range of 2.4 GHz to 2.5 GHz of the industrial, scientific and medical (ISM) radio frequency band. A remote interrogation system identifies the instantaneous resonance frequency of the sensor by transmitting pulses of radio frequency (RF) signal and recording the ring back of the resonator. The ring back is down converted and analyzed to determine the resonance frequency of the sensor. Two possible applications of the sensor, i.e. voltage measurement and defect detection of insulators, are demonstrated by experimental results.
February 2017

Recently the research community is considering with a growing interest the adoption of IWSNs in application contexts such as real-time (industrial) communications and distributed measurement systems. These types of applications typically impose very tight equirements to the underlying communication systems and, moreover, they might have to cope with the intrinsic unreliability of wireless networks. It is hence needed an accurate characterization of these networks' behavior, from a metrological point of view. Suitable measurement systems have to be realized, and experiments performed aimed at evaluating some of the most appropriate performance indicators. Unfortunately, despite the appealing opportunities provided by IWSNs, their adoption is just at its beginning. It is clear that a comprehensive experimental analysis of their behavior would improve theoretical analysis, simulations and design of the network, since the consequent increased accuracy of models could reduce the source of difference between real and expected behaviors. With the work presented in this thesis the author would provide some original contribution in the field of measurements on real-time wireless networks adopted for industrial communications and distributed measurement systems. In this context, one of the most relevant aspect to be considered is represented, as described in the literature, by interference that possibly arises from "intentional" communications taking place in external systems. In order to address such an issue, some simulation techniques have been considered. As a result, they lead to the development of a network simulator software tool that enabled a cross-layer analysis of interference. This activity stimulated an in-depth study of the IEEE 802.15.4 and IEEE 802.11 communication protocols. Particularly, medium access techniques have been analyzed in the perspective of IWSN applications. On this basis new and effective methods for increasing the network reliability have been proposed, along with fair packet retransmission scheduling methods. Moreover, new rate adaptation algorithms for wireless networks specifically designed for real-time communication purposes, exploiting the high robustness of low transmission rates have been proposed. Finally, since the reliability of a network strongly depends on the real behavior of the employed devices, an experimental approach for the measurement of the devices characteristics is presented, with the aim of providing suitable models and methods for designers.
La comunità scientifica, recentemente, sta considerando con sempre maggiore interesse l'adozione di reti di sensori wireless in contesti come le comunicazioni real-time (industriali) e i sistemi di misura distribuiti. Queste applicazioni richiedono tipicamente, al sistema di comunicazione, di soddisfare requisiti molto stringenti, considerando anche l'intrinseca inaffidabilità del canale radio. Risulta quindi necessaria un'accurata caratterizzazione, in termini metrologici, del comportamento di questa tipologia di reti, tramite sistemi di misura adatti alla valutazione dei più appropriati indici di prestazioni. Sfortunatemente, infatti, l'impiego di questi sistemi è ancora agli inizi, nonostante le interessanti prospettive applicative fornite dalle reti wireless real-time. Appare quindi chiaro come un'accurata caratterizzazione sperimentale del loro comportamento reale migliorerebbe sensibilmente l'efficacia delle analisi teoriche, delle simulazioni e di conseguenza del progetto della rete, risultando incrementata l'accuratezza dei modelli teorici e limitate le sorgenti di deviazione tra i risultati attesi e quelli sperimentali. Con il lavoro presentato in questa tesi, l'autore intende fornire contributi originali nel campo delle misure sulle reti wireless real-time adottate per comunicazioni industriali e sistemi di misura distribuiti. In questo contesto, uno dei principali aspetti da considerare, come si evince dalla letteratura, è dato dall'interferenza dovuta a comunicazioni "intenzionali" da parte di sistemi esterni. Per affrontare quest'analisi si sono inizialmente valutate alcune tecniche di simulazione. Questo ha portato allo sviluppo di un software di simulazione per reti di comunicazione specificamente progettato per l'analisi cross-layer dei fenomeni d'interferenza. Quest'attività ha stimolato uno studio approfondito dei protocolli di comunicazione IEEE 802.15.4 and IEEE 802.11. Nell'ottica del loro impiego per reti wireless real-time, particolare enfasi è stata rivolta alle tecniche di accesso al mezzo specificate nei citati standard. Sulla base di quest'analisi, sono stati proposti alcuni metodi originali per incrementare l'affidabilità di questi sistemi, considerando ad esempio nuove politiche di ritrasmissione per reti basate su polling ciclico. Inoltre sono stati proposti nuovi algoritmi per l'adattamento automatico del rate di trasmissione per reti IEEE 802.11, progettati per l'impiego specifico in un contesto di reti real-time. Infine, considerando che l'affidabilità di una rete in questo contesto dipende strettamente dal comportamento fisico dei componenti impiegati, viene proposto un approccio sperimentale per la misura e caratterizzazione dei ritardi introdotti dai dispositivi di rete, allo scopo di fornire metodi e modelli adeguati in un contesto di progettazione di rete.

Wireless channel characterization is important for determining both the requirements for a wireless system and its resulting reliability. Wireless systems are becoming ever more pervasive and thus are expected to operate in increasingly more cluttered environments. While these devices may be fixed in location, the channel is still far from ideal due to multipath. Under such conditions, it is desirable to have a means of taking wireless channel measurements in a low-cost and distributed manner, which is not always possible using typical channel measurement equipment. This thesis leverages a software-defined radio (SDR) platform to perform wideband wireless channel measurements. Specifically, the system can measure the scalar frequency response of a wireless channel in a distributed manner and provides measurements with an average mean-squared error of 0.018 % σ and a median error not exceeding 0.631 dB when compared to measurements taken with a vector network analyzer. This accuracy holds true in a highly multipath environment, with a measurement range of ~40 dB. The system is also capable of scaling to multiple wireless links which will be measured simultaneously (up to three links are demonstrated). After validating the measurement system, a measurement campaign is undertook using the system in a highly multipath environment to demonstrate a possible application of the system.

Clock synchronization is one of fundamental requirements in distributed networks. However, the imperfection of crystal oscillators is a potential hurdle for network-wide collaboration and degrades the performance of cooperative applications. Since clock discrepancy among nodes is inevitable, many software and hardware attempts have been introduced to meet synchronization requirements. Most of the attempts are built on communication protocols that demand timestamp exchanges to improve synchronization accuracy or resource efficiency. However, link delay and environmental changes sometimes impede these synchronization efforts that achieve in desired accuracy. First, the clock synchronization problem was examined in networks where nodes lack the high accuracy oscillators or programmable network interfaces some previous protocols depend on. Next, a stochastic and practical clock model was developed by using information criteria which followed the principle of Occam's razor. The model was optimized in terms of the number of parameters. Simulation by using real measurements on low-powered micro-controllers validated the derived clock model. Last, based on the model, a clock tracking algorithm was proposed to achieve high synchronization accuracy between unstable clocks. This algorithm employed the Kalman filter to track clock offset and skew. Extensive simulations demonstrated that the proposed synchronization algorithm not only could follow the clock uncertainties shown in real measurements but also was tolerant to corrupted timestamp deliveries. Clock oscillators are vulnerable to noises and environmental changes. As a second approach, clock estimation technique that took circumstances into consideration was proposed. Through experiments on mobile devices, the obstacles were clarified in synchronization over wireless networks. While the causes of clock inaccuracy were focused on, the effect of environmental changes on clock drifting was investigated. The analysis of the observations inspired an M-estimator of clock error that was accurate but under dominant disturbances such as oscillator instability and random network delay. A Kalman filter was designed to compensate with temperature changes and estimate clock offset and skew. The proposed temperature-compensated Kalman filter achieved the better estimates of clock offset and skew by adjusting frequency shifts caused by temperature changes. The proposed Kalman filter-based clock synchronization was implemented in C. A real-time operation was proved by clock tracking between two mobile platforms that the synchronization technique was implemented on. Moreover, the technique was converted to fixed-point algorithm, which might degrade performance, to evaluate the synchronizing operation on fixed-point processors. The fixed-point simulation reported performance degradation caused by limited hardware resources; however, it also corroborated the applicability of the synchronization technique.

Typically a wireless LAN infrastructure is designed and installed by Networking professionals. These individuals are extremely familiar with wired networks, but are often unfamiliar with wireless networks. Thus, Wireless LAN installations are currently handicapped by the lack of an accurate, performance prediction model that is intuitive for use by non-wireless professionals. To provide a solution to this problem, this thesis presents a method of predicting the expected wireless LAN throughput using a site-specific model of an indoor environment. In order to develop this throughput prediction model, two wireless LAN throughput measurement products, LANFielder and SiteSpy, were created. These two products, which are patent pending, allow site-specific network performance measurements to be made. These two software packages were used to conduct an extensive measurement campaign to evaluate the performance of two IEEE 802.11b access points (APs) under ideal, multiuser, and interference scenarios. The data from this measurement campaign was then used to create empirically based throughput prediction models. The resulting models were first developed using RSSI measurements and then confirmed using predicted signal strength parameters.
Master of Science

This thesis describes a performance measurement tool that allows a user to measure network performance using a handheld device. The measurement tool consists of a client program that runs on a Microsoft Pocket PC device and a server program that runs on a regular Microsoft Windows computer. Both programs are Windows applications implemented in C/C++ using the Microsoft Embedded Visual Tool and Microsoft Visual Studio. The use of a Pocket PC device provides mobility to users, which can save time and energy when performing experiments. The thesis describes the design of the performance measurement application, implementation issues, and tests conducted using the tool.
Master of Science

As mobile hand-held devices such as cell phones and personal digital assistants are battery operated, it is important to minimize their energy consumption. The limited lifetime of the battery is always a problem for all portable devices. Although battery technology has undergone a massive development over the years, it has not kept pace with other technologies. Therefore, research needs to be done to use the limited life time of the battery in an efficient way. With developments in science and technology, the power consumption of portable devices has been brought down due to the decrease in the size of the display and optimization of components. The trend toward smaller sizes of portable devices involved is responsible for the wireless network interface consuming a larger share of overall power consumption of a system. In order to optimize the power consumption of wireless communication, we should be aware of the power consumption pattern. Accurate energy models are required for designing and testing energy aware protocols. The accuracy of these energy models and their contribution toward energy aware protocol design depend on the accuracy and availability of sufficient data about power consumption of these devices. This work contributes to the building of such a power consumption database through a series of measurements of currently available Wireless Network Interface Cards (WNIC) and Radio Frequency Identification Devices (RFID). These measurements also help in understanding the behavior of these technologies at the lower levels of the network stack.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Electrical Engineering and Computer Science.

Hydropower has been around for more than a century and is considered a mature technology, but with recent advancements in power electronics and simulation capability new exciting ways to increase efficiency and reliability is possible. At Uppsala University a brushless exciter has been constructed for the experimental test rig, SVANTE. Power electronics are mounted on the shaft for control of the generator's excitation current. In addition a wireless control and measurement system is needed to provide the desired switching patterns to the power electronics and to evaluate performance of the system. In this thesis a shaft mounted embedded system for control and measurement is constructed as well as magnetic field sensors with measurement range up to 700mT. The computational power comes from a National Instruments sbRIO-9606. The system has 14 individual totem pole power electronics driving channels, 48 analog input channels for current signals and it communicates wirelessly through a bluetooth connection. The system is tested and works satisfactory but has not been mounted on the rotating side of the generator due to delays in the manufacturing.

Wireless access networks today consume 0.5 percent of the global energy. Rapidly growing demand for capacity will further increase the energy consumption. Thus, improving energy efficiency has a great importance not only for environmental awareness but also to lower the operational cost of network operators. However, current networks which are optimized based on non-energy related objectives introduce challenges towards green wireless access networks. In this thesis we investigate the solutions at the deployment level and handle energy efficiency assessment issues in wireless access networks. The precise characterization of the power consumption of the whole network has a crucial importance in order to obtain consistent conclusions from any proposed solution at the network level. For this purpose, we propose a novel power consumption model  considering  the impact of backhaul for two established technologies, i.e., fiber and microwave, which is often ignored in the literature. We show that there is a tradeoff between the power saved by using low power base stations and the excess power that has to be spent for backhauling their traffic which therefore needs to carefully be included into energy efficiency analysis. Furthermore, among the solutions that are analyzed, fiber-based backhaul solution is identified to outperform microwave regardless of the considered topology. The proposed model is then used to gain a general insight regarding the important design parameters and their possible impact on energy- and cost oriented network design. To this end, we present a  high-level framework to see the main tradeoffs between energy, infrastructure cost, spectrum and show that future high-capacity systems are increasingly limited by infrastructure and energy costs where spectrum has a strong positive impact on both. We then investigate different network deployment strategies to improve the energy efficiency where we focus on the impact of various base station types, cell size, power consumption parameters and the capacity demand. We propose a refined power consumption model where the parameters are determined in accordance with cell size. We show that network densification can only be justified when capacity expansion is anticipated and over-provisioning of the network is not plausible for greener network. The improvement through heterogeneous networks is indicated to be highly related to the traffic demand where up to 30% improvement is feasible for high area throughput targets. Furthermore, we consider the problem of energy efficiency assessment at the network level in order to allow operators to know their current status and quantify the potential energy savings of different solutions to establish future strategies. We propose elaborate metric forms that can characterize the efficiency and a methodology that indicate how to perform a reliable and accurate measurement considering the complexity of wireless networks. We show the weakness of the current metrics reporting the "effectiveness" and how these might indicate disputable improvement directions unless they are properly revised. This illustrates the need for a standardized network level energy efficiency evaluation methodology towards green wireless access.

QC 20121109

Energy-efficient wireless networking (eWIN)

Wireless Sensor Networks (WSNets), consisting of a lot of Wireless Sensor Nodes (WSNs), play an important role in structural health and machine condition monitoring. But the WSNs provided by the current market cannot meet the diversity of application requirements because they have limited functions, unreliable node performance, high node cost, high system redundancy, and short node lifespan. The aim of the research is to design the architecture of a WSN with low power consumption and node cost, which can be dynamically configured according to application requirements for structural health and machine condition monitoring. This research investigates the improvement of node performance and reliability through the new design methodologies and the extension of node lifespan by interfacing energy harvesters and implementing node power management. The main contributions of the research are presented from the following aspects:1. Model development of node architecture for application diversityThe merits of model include: (1) The proposed node architecture can be dynamically configured in terms of application requirements for reducing system redundancy, power consumption and cost; (2) It supports multichannel signal measurement with the synchronous and asynchronous signal sampling modules and three interface circuits; (3)The model parameters can be calculated; (4) As the model is based on discrete electronic components, it can be implemented by using Components-Off-The-Shelf (COTS).2. A novel pipeline design of the built-in ADC inside a microprocessorThe merit of proposed pipeline solution lies in that the sampling time of the built-in ADCs is reduced to one third of the original value, when the ADC operates in sequence sampling mode based on multichannel signal measurement.3. Self-adjusting measurement of sampled signal amplitude This work provides a novel method to avoid the distortion of sampled signals even though the environmental signal changes randomly and over the sampling range of the node ADC. The proposed method can be implemented with four different solutions.4. Interface design to support energy harvesting The proposed interface will allow to: (1) collect the paroxysmal ambient energy as more as possible; (2) store energy to a distribution super-capacitor array; (3) harvest electrical energy at high voltage using piezoelectric materials without any transformer; (4) support the diversity of energy transducers; and (5) perform with high conversion efficiency.5. A new network task scheduling model for node wireless transceiver The model allows to: (1) calculate node power consumption according to network task scheduling; (2) obtain the optimal policy for scheduling network task.6. A new work-flow model for a WSN The model provides an easy way to (1) calculate node power consumption according to the work flow inside a WSN; (2) take fully advantage of the power modes of node electronic components rather than outside factors; (3) improve effectively node design.

This thesis is focused on a study on modeling and measurement of the indoor radio and infrared channels. Both channels have been studied, compared and their vital differences identified. Initially, an infrared channel model was developed that was not similar to any existing models for the infrared domain. The wireless diffuse infrared channel is solely used indoors and is usually confined within a room. Conventional channel models are described, but their disadvantage is heavy time and processor requirements. A new model is introduced, in which the approach is different from the traditional methods in the way that it discretises the delay range instead of the physical characteristics of the environment. The new model offers accurate results without the increased time and processor requirements compared with traditional techniques. Following the characterisation of the infrared channel, a wideband radio propagation campaign took place in two different buildings that allowed valuable insight into the mobile radio channel. Time domain analysis of the measurement results allowed the careful study of the radio channel and produced interesting results as far as RMS delay spread and Power Delay Statistics are concerned. It has been shown that the RMS delay spread is not always dependent on antenna separation, while it was found to be highly dependent on the clutter present on the measurement environment. The infrared model was finally converted to account for radio propagation. Traditional channel models for indoor propagation prediction are described, while the major differences of the infrared and radio channel are mentioned. The radio channel prediction benefits from the accuracy of the infrared model, where a very high accuracy is necessary in order to predict the effect of scattering. A simple measurement campaign has been introduced in order to validate the results of the simulation tool and a comparison with the most important wideband channel models has been performed, along with higher frequency measurements where scattering is more important. The results present a good fit to the measurements and models in the literature, and empirical conclusions relative to the scattering characteristics of the radio channel are drawn from these comparisons.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California
Testing aircraft brake and tire systems often results in tire temperatures that makes the aircraft unsafe to approach (due to explosion risk) for up to 45 minutes; this complicates cost effective test execution. This paper describes work on a wireless sensor system that measures multiple tire temperatures and transmits the data to someone at a safe distance (>300 ft). The solution consists of a sensor patch adhered directly to the tire which measures the tire temperature. The patch transmits these measurements to off-tire reader/relay nodes that subsequently sends the data to a system controller and display device.

ABSTRACT For a variety of wireless sensor network applications, sensor nodes may find their received signal strengths dominated by small-scale propagation effects. Particularly impacted are applications designed to monitor structural health and environmental conditions in metal cavities such as aircraft, busses, and shipping containers. Small changes in each sensor’s position or carrier frequency can cause large variations in this received signal strength, thereby compromising link connectivity. We leverage a technique called Wireless Sensors Sensing Wireless (WSSW) in which wireless sensors act as scalar network analyzers in order to characterize their own environment. WSSW data can enable sensors to react to particularly bad fading, such as hyper-Rayleigh, by switching to a good channel or by implementing other mitigation techniques, such as utilizing a diversity antenna. In this work, the WSSW concept has been extended to accommodate mesh networks and include a spectrum analysis capability for recognizing potentially interfering wireless activity. The test of mitigation techniques is often problematic since application sites are far from controlled environments and are often difficult to access. To address this problem, we have developed a Compact Reconfigurable Channel Emulator (CRCE) to create a laboratory environment that is configurable to a variety of repeatable fading scenarios. With the CRCE, fading characteristics found at a specific wireless sensor network location may be replicated inside the chamber to discover the connectivity capabilities of the sensors and the effectiveness of diversity schemes (e.g., channel switching or multi-element antenna arrays).

碩士
國立成功大學
電機工程學系碩博士班
93
With time advanced，the technology of locating becomes better and better . The GPS (Global Positioning System)、GSM (Global System for Mobile Communication) and Wireless Location System technology have extensively applied in our daily life . We are also toward this goal to design a system of small range Wireless Distance Measurement. The specifications of our designed system are: Operating frequency : 500MHz，Measurement Range : 60 cm × 60 cm，Carrier Frequency : 5GHz，Precision : 1/100. 　According to the specification we designed， completing the components ,RF Transmitter and PLL, in whole system by TSMC CMOS process . To integrate it in the system, and adding a high precision PFD (Phase Detector) to simulate the results。Finally，we discuss the results and errors。

碩士
義守大學
電機工程學系
101
In this master thesis, we successfully establish an integrated wireless application for homecare. Wireless RF medical instruments such as blood pressure, glucose measurement, weight, and SpO2 are the devices for measuring the physiological signals. These signals are then wirelessly transmitted and received by USB RF Dongle connected to the mobile devices or laptops. The information is then stored in a physiological database that is specifically designed for the elderly. The environment being established strengthens homecare system and offers a variety of biomedical instrumentation for caregivers to promote health and prolong the elderly care services.

碩士
國立清華大學
電機工程學系
95
In the wireless communication systems, time-varying multi-path propagation is a common phenomenon, which introduces a rich channel structure into the radio interface. On one hand, this phenomenon brings us precious time diversity and frequency diversity which are crucial for the survival of a wireless system. On the other hand, if we do not make a good use of the wireless channel information, this phenomenon will instead cause signal interference which results in various system problems in terms of signal synchronization error, channel estimation error, and data detection error. In other words, by exploring the wireless channel structure, we can obtain better signal synchronization, mitigate the system interference, and thus significantly improve accuracy of data detection. Therefore, when developing a wireless communication system, in order to guarantee high efficiency and outstanding performance of such a system, it is important to find out the wireless channel structure. In the indoor wireless channel measurement, the channel property usually differs a lot at different channel environments, which can be categorized into several types. In this thesis, we conduct numbers of measurements in several selected scenarios at Research-and-Development Building to realistically capture the channel structure in various wireless environments. A network analyzer is used to record the signal variations measured at different locations in the frequency domain. The measurements are then further analyzed to look into the delay spread caused by the effect of multipath propagation. We divide the analysis result into several distinct scenarios for various wireless communication environments so as to help make the best design of communication systems.

Tese de doutoramento do Programa de Doutoramento em Ciências e Tecnologias da Informação, apresentada ao Departamento de Engenharia Informática da Faculdade de Ciências e Tecnologia da Universidade de Coimbra
The use of Wireless Sensor Networks (WSNs) has opened the possibility of a new set of applications that are having a growing impact in personal and business activities. However, most of its application scenarios have been restricted to non-critical environments, with WSN being operated with no controlled performance. The aim to extend the flexibility and unique characteristics of these networks to a broader set of applications and scenarios, such as industrial and health care, poses new challenges that must be met with a new approach. In such environments, WSNs may have significant benefits over traditional networks, such as enabling a deeper control, lowering deployment and maintenance costs, and by offering simple reconfiguration and adaptation to changing business models. To enable WSNs with controlled performance the first step is to be able to characterize and describe the requirements that the network needs to fulfil. The second step is to be able to translate those requirements into effective metrics. The metrics to be used must be adapted to the unique characteristics of WSNs, taking into account its processing, energy and storage restrictions. The next step is to monitor those metrics, and allow for their debugging when necessary, a procedure that involves their collection to a central base station where further treatment, with better resources, is possible and where an effective network monitoring can be achieved. The last step completes the cycle and corresponds to the ability to dynamically act in the network, based on the metrics received, either automatically (by each node or by a central monitoring tool connected to the sink) or through the Network Manager. In this thesis, the performance control life cycle of a WSN is addressed, especially considering the performance needed in industrial facilities, one of the most demanding scenarios for these networks, requiring not only strict performance boundaries but also real-time monitoring of the network. Valuable insights of these environments were possible through the participation in project FP7 GINSENG. First, a new classification of WSN application scenarios, that also includes critical environments, and a proposal of a new taxonomic tree of WSNs Quality of Sensing (QoSensing) requirements, including WSNs with performance control, is presented. The objective is to characterize WSNs needs, both in the information as in the network planes, and to create a reference classification that lays the foundations for the creation of effective metrics that permit the evaluation and verification of each requirement. The taxonomy was applied to different types of GINSENG scenarios and also to well-known types of applications found in the literature for validation. Having as reference the taxonomy created, and the specificities of WSNs, a study of different types of metrics is presented and their characteristics and applicability to WSNs discussed. In this context, collective metrics are introduced as a useful type of metric to address the evaluation of the global network QoSensing, while using least resources than other types of metrics and hiding the normal fluctuation of values in networks subject to many hazards. Simulations showed that collective metrics are an efficient alternative to individual or aggregated metrics, in the assessing of the global QoSensing of a WSN. Next, the Network performance branch of the previously proposed taxonomy is analysed and a general set of metrics, adapted to each of the phases of the life cycle of a WSN, is proposed to address it. A reduced set of metrics specifically targeted to WSNs in industrial environments, focusing collective metrics for the operation phase of the network, is also proposed. The control and maintenance of levels of performance, based on a continued evaluation of specific metrics and in the dynamic actuation in the network was also addressed, with the participation in the creation of a new protocol that deals with interferences. Finally, a new protocol that collects performance data from the network is proposed. By using data fusion, the protocol presents an effective way to monitor the global performance of the network, while guaranteeing that if some error or problem occurs, an alert is generated and immediately sent to sink. The evaluation of this protocol, made by simulation, showed a decrease in the energy spent and in the interference generated by the number of packets sent, while providing for a global knowledge of the overall performance of the network. The thesis also contributed to project GINSENG, namely in the classification of the project scenarios, according to the taxonomy proposed, and in the specification of the performance metrics to be used.
A utilização de Redes de Sensores sem Fios (RSSF) possibilitou o aparecimento de um novo conjunto de aplicações com um impacto crescente em vários ramos de actividade, desde pessoais a negócios. No entanto, a maioria dos seus cenários de utilização tem estado restrita a ambientes não críticos, com as RSSF a funcionarem sem controlo de performance. O objectivo de estender a flexibilidade e demais características únicas destas redes a um conjunto mais vasto de aplicações e cenários, como cenários industriais ou de assistência médica, cria novos desafios que só podem ser superados através de uma nova abordagem. Nestes cenários, as RSSF apresentam benefícios significativos em relação às redes tradicionais, como um controlo mais detalhado do meio, custos de implementação e manutenção mais baixos, e por oferecerem uma reconfiguração simples e adaptável à evolução dos modelos de negócio. De modo a permitir a existência de RSSF com performance controlada, o primeiro passo é conseguir caracterizar e descrever os seus requisitos. O segundo passo é traduzir esses requisitos em métricas. As métricas a usar necessitam de estar adaptadas às características únicas das RSSF, tendo em conta as suas restrições de processamento, de energia e de memória. De seguida, é necessário proceder à monitorização dessas métricas, e permitir operações de depuração de erros na rede, o que envolve o envio dessas mesmas métricas para uma estação base central, onde podem ser sujeitas a uma análise mais profunda através da utilização de melhores recursos, e onde uma monitorização efectiva da sua performance pode ser efectuada. O último passo completa o ciclo e corresponde à capacidade de actuar dinamicamente na rede, com base em valores obtidos através de métricas, quer de forma automática (através do próprio nó ou através de uma ferramenta de monitorização ligada à estação base), quer através da actuação do gestor de rede. Nesta tese, o ciclo de vida de uma RSSF com performance controlada é abordado, sendo especialmente focadas as redes para ambientes industriais, um dos cenários mais complexos e exigentes para as RSSF, requerendo não só limites apertados para a performance, como também uma monitorização em tempo-real. Os conhecimentos adquiridos pela participação no projecto FP7 GINSENG foram especialmente importantes para a análise deste cenário. Primeiro, uma nova classificação dos cenários usados pelas aplicações de RSSF (com e sem performance controlada) e uma nova taxonomia de requisitos para RSSF, são propostas. O objectivo é caracterizar os requisitos necessários às RSSF, quer no plano da informação, como no de rede, e criar uma classificação de referência que permita o desenvolvimento posterior de métricas que possam avaliar cada um desses requisitos. A taxonomia foi aplicada a vários cenários do projecto GINSENG e também em aplicações típicas de RSSF, para validação. Tendo como base a taxonomia desenvolvida e as especificidades das RSSF, é efectuado depois um estudo sobre os diferentes tipos de métricas, os quais são depois analisados tendo em conta a sua aplicabilidade. Neste contexto são introduzidas as métricas colectivas. Este tipo de métricas é adequado à medição do desempenho global das RSSF, gastando menos recursos que os demais tipos e escondendo as normais flutuações de valores produzidos por estas redes. Testes por simulação mostraram que as métricas colectivas são uma alternativa eficiente quer às métricas individuais como às agregadas, na avaliação do desempenho global da RSSF (ou a sua qualidade sensorial). De seguida, o ramo de performance de rede da taxonomia proposta é analisado e como resultado é criado um quadro de referência com métricas para o poder avaliar, divididas pela fase de vida da rede em que devem ser aplicadas. A proposta de um quadro de métricas mais reduzido, contendo métricas especialmente adequadas à avaliação de desempenho de RSSF em ambientes industrias e que foca o uso de métricas colectivas para a fase de operação da rede, é também proposto. O controlo e manutenção do desempenho da rede baseado numa contínua avaliação de métricas específicas é também abordado através da participação na criação de um novo protocolo que lida com interferências na rede. Por fim, é proposto um novo protocolo para recolha das informações de performance da rede. Este protocolo permite a avaliação global de desempenho da rede ao mesmo tempo que garante que, caso necessário, um alerta seja gerado e enviado directamente para a estação base. A avaliação deste protocolo foi feita através de simulação, tendo mostrado ganhos de energia e redução do número de interferências na rede, quando comparado com o envio de métricas individuais, mantendo um conhecimento constante do desempenho global da rede. Esta tese também contribuiu para o projecto GINSENG, nomeadamente na classificação dos seus vários cenários, de acordo com a taxonomia desenvolvida, e na especificação das métricas de performance a usar.

碩士
國立臺北科技大學
機電整合研究所
95
This study aim to develop a measurement platform system for communication product that include hardware instrument and software interface. The system can fix DUT (Device Under Test), turn DUT to assigned test position in the chamber and upgrade the 2D measurement to 3D measurement system with two-axis rotation capability. Because the fixture and mechanic components in the chamber allow less reflective EM wave, all materials of the components in the chamber must have low dielectric and have less EM effect. There are many factories effect the measurement result. If we can find and control the key factor, we can get the best test result. This study applies “factorial design of experiments” method to find out the main effect factor of radiation test and try to improve the EM effect of the measurement platform. Finally, we can develop one kind of 3D measurement platform with low EM reflection and high performance.

Electrical and Computer Engineering
A high performance, wireless bio-impedance measurement system has been designed for the purpose of monitoring essential electrical properties of the heart during cardiac ablation. The system is broken into three parts: a spring-loaded device to house a tetrapolar surface probe and sensors, a wireless bio-impedance measurement system, and a desktop base station for graphical data display and acquisition. The system is specifically designed for a tetrapolar-electrode configuration where the two outer electrodes served as a current source operating at 20 kHz with an amplitude of 100 µArms and the two inner electrodes served as voltage sensing electrodes. In addition, the system also has a dedicated channel for current sense. The system is designed to be modular and reconfigurable for different measurement needs. Epochs of both discrete voltage and current samples generated by the voltage-controlled current source are processed using a digital signal processing algorithms to generate admittance measurements. In addition to the admittance’s magnitude and phase, pressure, electrocardiogram (EKG), and temperature (two channels) data are also acquired. The measurements are then wirelessly transmitted from the bio-impedance measurement system to a base station where data are processed and viewed graphically. The final system updates the admittance, pressure, EKG, and two temperature channels at 320 Hz, consumes less than 3 W, and has percent of measurement errors of 7 % and 2 % for capacitive and resistive measurements in the range of 100 pF to 10000 pF and 300 Ω to 1600 Ω, respectively. Instrument design, calibration, verification, and modeling are at the heart of this thesis. In the future, the instrument will be deployed for various bio-impedance measurements that require a high degree of linearity, precision, and a wide input range.
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碩士
朝陽科技大學
資訊工程系碩士班
101
With the constant progress of technology, machine of hospital continuation development of miniaturized from large and inconvenient, so that users can handy to carry and use in daily life or exercise. Minimization physiological sensing instruments developed in this study, a lead ECG and a three-axis accelerometer can be used to measure heart rate, and display the body motion, The study hardware are two versions of the Bluetooth and the ZigBee. Due to the measurement of dynamic heart rate necessary to remove the noise in the ECG signal. Firmware contains digital signal processing and heart rate algorithm, this algorithm can be ambulatory electrocardiogram, calculate the R-wave peak position, and then immediately display a stable heart rate. This device can be applied to home care system in future.

碩士
華梵大學
教育學系研究所
86
In this thesis I design a wireless modem with 64Kbps data rate. Using this modem, I measured the bit error rate (BER), frame error rate (FER) and the receiving power strength in different environments. Based on the measured data, I have a chance to check some communication theories as well as understand the characteristics of wireless channels. This wireless modem employs the direct sequence spread spectrum (DSSS) technique. The PN code I use is the extended balanced Gold code with length 32. The modem contains two parts. One is the baseband subsystem, which is composed of a spread spectrum transceiver (SST) IC (AIC9001) and a microprocessor (89C51). The other is the ARF9003 RF module. Our measurement environments include laboratories, hallway, corner, mountain-top basketball-court, office, factory and an apartment. I hope that the data I obtained in the experiments can help people understand the statistic characteristics of wireless channels.

碩士
國立高雄第一科技大學
電腦與通訊工程系碩士班
105
In this thesis a set of cellular-phone-based application program, as a measurement tool, is developed to analyze signal quality of mobile data transmission. The measured signal data are analyzed and could be employed to improve and optimize the base station configuration. Because the progress and popularize of wireless communication technology, the applications of wireless communication technology in life have been rapidly developed. Especially the development of 3G/UMTS and 4G/LTE high-speed access technology enables the use of wireless data networks become more convenient. However, the users experience a big gap of quality performance, in the application level, to the default performance of wireless networks. This is because the construction of the cellular system cannot achieve the perfect configuration, and this issue becomes a variety of wireless carriers who are very much hope to improve. They continue to invest a lot of resources in the measurement, review and improvement of signal quality. Due to the industry's strong demand for effective maintenance of signal quality, in this paper, based on the wireless data signal measurement methods and data access technology, effective measurement tools are developed and constructed to analyze the measured signals. In addition, the signal measurement points set a lot of possibilities, so it will produce a lot of data in the dynamic measurement. The generated data will be saved in the form of data warehouse. In this thesis, using of Android Studio software, measurement application tools are developed based on mobile phones. Android Studio software has features such as "Gradle" build tools, edit pages and live previews. As compared to Eclipse, which is a commonly software to develop Android phone apps, Android Studio software has advantages in the boot speed, response speed, and the accessing time of memory. In addition, Android Studio software has a shorter development time and can achieve the benefits of rapid implementation of the application programs. Here, the application programs can analyze the collected data that are transmitted back to the database, with a simple approach based on telecommunication theory, to compare and analyze the online services provided by different wireless carriers. This program can help users to understand the merits of signal quality provided by their wireless carriers. However, quality of mobile phone can also affect the quality of the received signal, but due to limitation in fund, this thesis does not compare the signal quality for different mobile phones.

碩士
國立臺灣大學
應用力學研究所
94
In this study, a wireless sensor network architecture with internet connectivity has been realized by modifying a commercially available wireless router to serve as the local controller center (LCC). This newly developed sensor network architecture, just like any other well-designed sensor network, can collect data from widespread wireless sensor networks through internet effciently. The so-called LCC’s centers can control the traffic of the local sensor network, collect data, and relay the data to backend servers thorough internet. This newly developed LCC runs open-source embedded ucLinux and is constructed by connecting a newly designed add-on transceiver to the USB port extention of a commercially available wireless Wi-Fi router. Recently, under the M-Taiwan program, the wireless LAN infrastructure has been widely built in public space. The architure proposed in this study provide quite an extensive route to extend the wireless LAN infrastrure into a sensor network infrastructure so as to facilitate large-scale sensor networks deployment.. By using the concept of Design Pattern in Object-Oriented Programming, a flexible Java-based data collecting program was also successly developed, which was detailed in this thesis as well. The native cross-platform characteristics of Java may realize the concept “Compile Once, Run Anywhere,” which can then provide us with an opportunity to extend the flexibility of the data collecting program on various hardware platforms. In addition, this study also attempts to develop a centimeter distance location determination method using TOA (time of arrival) method. To have centimeter resolution by using the TOA mehod, the timing resolution has to be in the picosencos range. A low-cost picoseconds level timing measuremnt circuit was successfully developed and verified to have 80 picosencos resolution. To fully utilize this timing circuitry, a low-drift RF (radio frequency) transceiver must be developed to measure the travlling time between sensor nodes. Some preliminary study and proof of concept has been completed and found that the RF transceiver drifting can be controlled to within 2 nanoseconds, which corresponds to 60 cm spatial resolution. A more stable transceiver that has shorter pulse transimission capability is suggested to be the next task in order to enhance the spatial resolution.

碩士
東海大學
電機工程學系
102
Due to the trend of more the elderly and fewer children, humans pay more attention to the health problem. Therefore, the measurement for vital signals and the biomedical technology appear to be very important. The purpose of the thesis referring to the wireless biomedical measurement system with remote monitoring is to help physicians measure the cared without distance restriction and to perform remote monitoring using wireless networks. In this research, we achieve the integrated application of health care via remote monitoring and wireless biomedical measurement. A remote medical care platform is built to enhance home care, self-management and prophylaxes of health for the elderly. The platform offers diversities of biomedical measurement, monitors the physical information and health condition for the cared, and then improves the care service for the elderly.