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Chander, Bhan Chander Bhan. "Photonics-based environmental sensors for automotive air quality monitoring." Electronic Thesis or Diss., Lyon, INSA, 2024. http://www.theses.fr/2024ISAL0120.
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Cette thèse explore les dispositifs de circuits photoniques intégrés (PIC) basés sur une plateforme en nitrure de silicium (SiN), en mettant l'accent sur leur potentiel pour la détection de particules dans l'air, un élément clé des capteurs de l'indice de qualité de l'air (AQI). La haute sensibilité volumique des résonateurs à anneaux (MRR) dans ces dispositifs permet la détection de faibles concentrations de particules, tandis que les forces optiques permettent le piégeage spécifique à la taille des particules. Pour relever les défis liés au piégeage de particules diélectriques de moins de 100 nm, cette recherche explore diverses structures photoniques, y compris des guides d'onde diélectriques, des résonateurs en mode d'ordre supérieur (HOM) et des guides d'onde plasmoniques hybrides. cette étude comprend leur conception, leur fabrication et leur compatibilité avec des plateformes industrielles telles que DAPHNE de STMicroelectronics. L'analyse des forces optiques, réalisée à l'aide de méthodes telles que le tenseur de contrainte de Maxwell (MST) et l'approximation de dipôle discret (DDA), fournit un cadre rigoureux pour optimiser la conception et évaluer différentes structures. Les résultats soulignent le potentiel des guides d'ondes HOM et des guides d'ondes plasmoniques hybrides pour le piégeage optique avancé et la détection de l'IQA, ouvrant ainsi la voie à des approches innovantes pour les applications de surveillance de l'environnementThis thesis explores photonic integrated circuit (PIC) devices based on a silicon nitride (SiN) platform, focusing on their potential for airborne particle detection, a key component of air quality index (AQI) sensors. The bulk sensitivity of the ring resonators (MRR) in these devices enables detection of low particle concentrations, while the optical forces enable size-specific trapping of particles. To address the challenges of trapping dielectric particles smaller than 100 nm, this research explores various photonic structures, including dielectric waveguides, higher-order mode (HOM) resonators and hybrid plasmonic waveguides. The study includes their design, fabrication and compatibility with industrial platforms such as STMicroelectronics' DAPHNE. Optical force analysis, using methods such as Maxwell's stress tensor (MST) and discrete dipole approximation (DDA), provides a rigorous framework for optimizing the design and evaluating different structures.The findings underscore the potential of HOM waveguides and hybrid plasmonic waveguides for advanced optical trapping and AQI sensing, paving the way for innovative approaches to environmental monitoring applications
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Grondin, Didier. "Développement d'un capteur de suies pour application automobile - Etude des paramètres clés affectant sa réponse." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEM012/document.
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Le transport routier est responsable d’une part des émissions de particules fines, notamment dans les grandes agglomérations. Celles-ci ayant des répercussions graves sur la santé humaine et l’environnement, des normes d’émissions des véhicules de plus en plus strictes sont mises en place. Des limites en nombre de particules sont imposées et une obligation de connaitre l’état de santé des organes de post-traitement des gaz d’échappement est également entrée en vigueur (On-Board Diagnostic : OBD).Les capteurs résistifs ont montré de bons résultats pour la mesure de la concentration massique des particules et ont l’avantage d’être simples à mettre en oeuvre, robustes et peu onéreux. Le principe de fonctionnement du capteur est basé sur la mesure de la conductance entre des électrodes de platine. Celle-ci augmente avec le dépôt de suies.L’objectif de ce travail de thèse est de parvenir à déterminer les paramètres clés qui affectent la réponse du capteur. Trois flux de suies présentant des distributions en taille différentes ont été sélectionnés et caractérisés. Un quatrième flux de suies a permis d’appréhender l’impact d’une concentration massique inférieure. La réponse du capteur à ces différents flux de suies a été étudiée. Nous avons montré que la sensibilité et le temps de réponse du capteur sont optimaux pour une tension de polarisation donnée entre les deux électrodes dont la valeur dépend de la distribution en taille des suies. Ce phénomène a été expliqué par les propriétés électriques différentes des suies et modélisé par un équilibre entre accumulation et combustion par effet Joule des suies déposées permettant de simuler la réponse temporelle du capteurRoad transport contributes to a part of the particulate matter emissions, especially in big cities. Due to the negative effect of these pollutants on the human health and environment, more and more stringent emission standards for automotive are applied. These emissions are now limited in number of particles per kilometer and the vehicle need to indicate when there is some failure of the systems of depollution (OBD: On-Board diagnostic).Resistive sensors have shown good results to measure soot particles mass concentration. They have advantage of being a simple and robust technology that can be easily manufactured at a cheap price. The sensor principle consists of conductance measurement between two platinum electrodes. Conductance increases with soot deposition. This work aims to define the key parameters that affect the sensors response. Three particles flow with different particles size distributions (centered at 90, 70 and 50 nm) were used and characterized. A fourth flow was used to see the impact of a lower mass concentration. The sensor response exposed to these different flows was studied. It was shown that the sensor sensibility and response times are optimal for a given polarization voltage between the electrodes whose value depends on the size distribution. This phenomenon was explained by the different electrical properties of the soot particles and modeled by equilibrium of soot accumulation and their combustion by Joule heating that permitting to simulate the sensor temporal response
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Ing, Garrick. "Distributed particle filters for object tracking in sensor networks." Thesis, McGill University, 2005. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=98971.
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A particle filter (PF) is a simulation-based algorithm used to solve estimation problems, such as object tracking. The PF works by maintaining a set of "particles" as candidate state descriptions of an object's position. The filter determines how well the set of particles describe the observations and fit the dynamic model, in order to form an object state estimate. The drawback of the basic PF is that the algorithm functions by collecting all data at a fusion centre. This leads to high communication and energy costs in a resource-limited network such as the sensor network. In this thesis, we analyze the PF to determine how it can be modified for efficient use in a sensor network. Our main priority is to keep communication and energy costs low since this increases the network lifetime. We propose two innovative particle filtering algorithms which minimizes the associated costs.
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Latiff, Nurul Mu'azzah Abdul. "Particle swarm optimisation for clustering in wireless sensor networks." Thesis, University of Newcastle Upon Tyne, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.489298.
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One of the mam characteristics which set wireless sensor networks apart from traditional networks is the inclusion of energy consumption as the highest priority optimisation goal. This is because these types of networks work under the general concept that the system lifetime needs to be extended as much as possible, whilst at the same time achieving efficient data forwarding and preventing route disconnections due to sensor node failure. Hence, the use of energy efficient infrastructure such as clustering n:ay lengthen the lifetime of the network and prevent network connectivity degradation through the utilisation of cluster heads. Since the optimal selection of cluster heads in a network belongs to nondeterministic polynomial (NP) hard problem, the use of approximation algorithms such as Particle Swarm Optimisation (PSO) are generally more suitable due to its simplicity and outstanding search strength. This PhD thesis investigates the application of the PSO algorithm in clustering ofwireless sensor networks. In view of the need to prolong sensor network lifetime, a centralised, energy efficient, cluster-based protocol is developed using the PSO algorithm. A new cost function has been defined, which takes into consideration three important factors, namely the expected network energy consumption, the intracluster distance and the remaining energy of the cluster heads. The clustering problem is then transformed into an optimisation problem, and the PSO algorithm is employed to search for the optimal set of cluster heads. Simulation results demonstrate that the proposed protocol using PSO obtains better data delivery and network lifetime, as well as improves network connectivity over its comparatives. In addition, the results confirm the efficiency of PSG in clustering problems, compared to other evolutionary algorithms. This thesis also considers the use of the PSO algorithm in clustering the wireless sensor networks with mobile nodes. For this purpose, the 'mobility factor is taken into account when defining the cluster membership and selecting the cluster heads in order to maintain network connectivity. Simulation results prove that this approach outperforms other well known protocols in terms of data delivery and network lifetime. Finally, a dynamic multi-objective clustering algorithm which automatically determines the optimum number of clusters is introduced. This algorithm, based on binary PSG, eliminates the need to set the number of clusters a priori. Furthermore, the use of multi-objective PSG can tackle the difficulty of tuning the cost function weights that properly scales the sub-objectives. Performance evaluation through simulation exhibits the superior strength of this algorithm in enhancing the network survivability.
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Ihler, Alexander T. (Alexander Thomas) 1976. "Inference in sensor networks : graphical models and particle methods." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/33206.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 175-183).
Sensor networks have quickly risen in importance over the last several years to become an active field of research, full of difficult problems and applications. At the same time, graphical models have shown themselves to be an extremely useful formalism for describing the underlying statistical structure of problems for sensor networks. In part, this is due to a number of efficient methods for solving inference problems defined on graphical models, but even more important is the fact that many of these methods (such as belief propagation) can be interpreted as a set of message passing operations, for which it is not difficult to describe a simple, distributed architecture in which each sensor performs local processing and fusion of information, and passes messages locally among neighboring sensors. At the same time, many of the tasks which are most important in sensor networks are characterized by such features as complex uncertainty and nonlinear observation processes. Particle filtering is one common technique for dealing with inference under these conditions in certain types of sequential problems, such as tracking of mobile objects.
(cont.) However, many sensor network applications do not have the necessary structure to apply particle filtering, and even when they do there are subtleties which arise due to the nature of a distributed inference process performed on a system with limited resources (such as power, bandwidth, and so forth). This thesis explores how the ideas of graphical models and sample-based representations of uncertainty such as are used in particle filtering can be applied to problems defined for sensor networks, in which we must consider the impact of resource limitations on our algorithms. In particular, we explore three related themes. We begin by describing how sample-based representations can be applied to solve inference problems defined on general graphical models. Limited communications, the primary restriction in most practical sensor networks, means that the messages which are passed in the inference process must be approximated in some way. Our second theme explores the consequences of such message approximations, and leads to results with implications both for distributed systems and the use of belief propagation more generally.
(cont.) This naturally raises a third theme, investigating the optimal cost of representing sample-based estimates of uncertainty so as to minimize the communications required. Our analysis shows several interesting differences between this problem and traditional source coding methods. We also use the metrics for message errors to define lossy or approximate4 encoders, and provide an example encoder capable of balancing communication costs with a measure on inferential error. Finally, we put all of these three themes to work to solve a difficult and important task in sensor networks. The self-localization problem for sensors networks involves the estimation of all sensor positions given a set of relative inter-sensor measurements in the network. We describe this problem as a graphical model, illustrate the complex uncertainties involved in the estimation process, and present a method of finding for both estimates of the sensor positions and their remaining uncertainty using a sample-based message passing algorithm. This method is capable of incorporating arbitrary noise distributions, including outlier processes, and by applying our lossy encoding algorithm can be used even when communications is relatively limited.
(cont.) We conclude the thesis with a summary of the work and its contributions, and a description of some of the many problems which remain open within the field.
y Alexander T. Ihler.
Ph.D.
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Campbell, Steven Conner. "DETERMINATION OF ACOUSTIC RADIATION EFFICIENCY VIA PARTICLE VELOCITY SENSOR WITH APPLICATIONS." UKnowledge, 2019. https://uknowledge.uky.edu/me_etds/133.
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Acoustic radiation efficiency is defined as the ratio of sound power radiated to the surface vibration power of a piston with equivalent surface area. It has been shown that the radiation efficiency is maximized and may exceed unity when the structural and acoustic wavelengths are approximately equal. The frequency at which this occurs is called the critical frequency and can be shifted with structural modifications. This has proven to be an effective way to reduce noise. The standard radiation efficiency measurement is comprised of an intensity scan for sound power measurement and accelerometer array for spatially averaged vibration determination. This method is difficult to apply to lightweight structures, complicated geometries, and when acoustic sources are in close proximity to one another. Recently, robust particle velocity sensors have been developed. Combined with a small microphone in the same instrument, particle velocity and sound pressure can be measured simultaneously and at the same location. This permits radiation efficiency to be measured using a non-contact approach with a single sensor. A suggested practice for measuring radiation efficiency has been developed and validated with several examples including two flat plates of different thickness, an oil pan, and components on a running small engine.
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Liu, Xiaoting. "Developing a scientific basis for utilisation of low-cost sensing technologies towards quantitative assessments of air pollution and its sources." Thesis, Queensland University of Technology, 2021. https://eprints.qut.edu.au/212115/1/Xiaoting_Liu_Thesis.pdf.
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This thesis develops a scientific basis for the use of low-cost sensing technologies for quantitative assessment of air pollution and its sources. It has extensively identified the capabilities and limitations of low-cost sensors in laboratory and field environments. Essentially, it has demonstrated that low-cost sensors are capable of monitoring air quality with a high degree of accuracy in different locations (e.g., highly polluted areas) and for different purposes (e.g., citizen science projects for raising environmental awareness).
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Jagtiani, Ashish V. "DEVELOPMENT OF NOVEL MULTICHANNEL RESISTIVE PULSE SENSORS FOR MICRO-PARTICLE DETECTION AND DIFFERENTIATION." University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1196284929.
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Kohlbacher, Anton. "Development of a Novel Relative Localization Sensor." Thesis, Luleå tekniska universitet, Rymdteknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-65515.
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By enabling coordinated task execution and movement, robotic swarms can achieve efficient exploration or disaster site management. When utilizing Ultra-wideband (UWB) radio technology for ranging, the proposed relative localization sensor can be made lightweight and relatively indifferent to the ambient environment. Infrastructure dependency is eliminated by making the whole sensor fit on a swarm agent, while allowing for a certain amount of positional error. In this thesis, a novel algorithm is implemented in to constrained hardware and compared to a more traditional trilateration approach. Both algorithms utilize Particle Swarm Optimization (PSO) to be more robust towards noise and achieves similar accuracy, but the proposed algorithm can run up to ten times faster. The antenna array which forms the localization sensor weighs only 56g, and achieves around 0.5m RMSE with a 10Hz update rate. Experiments show that the accuracy can be further improved if the rotational bias observed in the UWB devices are compensated for.
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Zhang, Zheng. "RESISTIVE PULSE SENSORS FOR POLLEN PARTICLE MEASUREMENTS." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1145070142.
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Fan, Zihao, and Wei Zhao. "Network Coverage Optimization Strategy in Wireless Sensor Networks Based on Particle Swarm Optimization." Thesis, Högskolan i Gävle, Akademin för teknik och miljö, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-9764.
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Wireless sensor network is an intelligent network system which has the self-monitoring functionality. It consists of many low-cost, low-power and small-sized sensor nodes that can communicate with each other to perform sensing and data processing. Acting as an important role in the system, network coverage usually has a huge effect on the system’s lifetime.In this thesis, particle swarm algorithm was used as a method to optimize the coverage in the coverage of wireless sensor network. A network coverage optimization strategy based on particle swarm optimization was proposed and MATLAB was used as a tool to apply the algorithm. The model used in this thesis is the probability sensing model and the coverage type is area coverage. Effectiveness of the algorithm is proved by simulation. The simulation of the algorithm suggests the optimal deployment can be determined if a certain parameter which in this thesis is the sensing range is given.
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Kiring, Aroland. "Shrinkage based particle filters for tracking in wireless sensor networks with correlated sparse measurements." Thesis, University of Sheffield, 2017. http://etheses.whiterose.ac.uk/20105/.
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This thesis focuses on the development of mobile tracking approaches in wireless sensor networks (WSNs) with correlated and sparse measurements. In wireless networks, devices have the ability to transfer information over the network nodes via wireless signals. The strength of a wireless signal at a receiver is referred as the received signal strength (RSS) and many wireless technologies such as Wi-Fi, ZigBee, the Global Positioning Systems (GPS), and other Satellite systems provide the RSS measurements for signal transmission. Due to the availability of RSS measurements, various tracking approaches in WSNs were developed based on the RSS measurements. Unfortunately, the feasibility of tracking using the RSS measurements is highly dependent on the connectivity of the wireless signals. The existing connectivity may be intermittently disrupted due to the low-battery status on the sensor node or temporarily sensor malfunction. In ad-hoc networks, the number of observation of the RSS measurements rapidly changing due to the movements of network nodes and mobile user. As a result, the tracking algorithms have limited data to perform state inference and this prevents accurate tracking. Furthermore, consecutive RSS measurements obtained from nearby sensor nodes exhibit spatio-temporal correlation, which provides extra information to be exploited. Exploiting the statistical information on the measurements noise covariance matrix increases the tracking accuracy. When the number of observations is relatively large, estimating the measurement noise covariance matrix is feasible. However, when they are relatively small, the covariance matrix estimation becomes ill-conditioned and non-invertible. In situations where the RSS measurements are corrupted by outliers, state inference can be misleading. Outliers can come from the sudden environmental disturbances, temporary sensor failures or even from the intrinsic noise of the sensor device. The outliers existence should be considered accordingly to avoid false and poor estimates. This thesis proposes first a shrinkage-based particle filter for mobile tracking in WSNs. It estimates the correlation in the RSS measurement using the shrinkage estimator. The shrinkage estimator overcomes the problems of ill-conditioned and non-invertibility of the measurement noise covariance matrix. The estimated covariance matrix is then applied to the particle filter. Secondly, it develops a robust shrinkage based particle filter for the problem of outliers in the RSS measurements. The proposed algorithm provides a non-parametric shrinkage estimate and represents a multiple model particle filter. The performances of both proposed filters are demonstrated over challenging scenarios for mobile tracking.
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Möslinger, Anja. "Particle Trajectory Simulations for SCIENA-N : Conversion surface design for an ENA sensor head." Thesis, Luleå tekniska universitet, Rymdteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-83034.
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This thesis serves as a preliminary design study for the combination of a flight-proven ion optics system (SWIM) with a conversion surface to create a small energetic neutral atom (ENA) sensor. It is planned to use this sensor as ENA sensor for the DFP-SCIENA instrument on Comet Interceptor. Due to the nature of the Comet Interceptor mission (ESA F-class mission with a maximum launch mass of 1000 kg) the development time for a new sensor that meets the size and weight restrictions is limited. The proposed combination of SWIM with a conversion surface is based on a proven ion optics design and should result in a compact sensor design. The main goal of this thesis was to simulate different conversion surface designs and evaluate their compatibility with the SWIM instrument. During this process the different designs were optimised based on the intermediate simulation results. The simulation process was performed by using SIMION to calculate particle trajectories. In the end, two different conversion surface designs yielded promising results. With both designs detailed simulations and data analysis were conducted to determine the different properties of the two designs. One of these designs was chosen to be further investigated for use on the Comet Interceptor mission.
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Kornilin, Dmitriy V. "Investigation of size, concentration and particle shapes in hydraulic systems using an in-line CMOS image matrix sensor." Thesis, University of Chester, 2018. http://hdl.handle.net/10034/621947.
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The theoretical and experimental investigation of the novel in-line CMOS image sensor was performed. This sensor is aimed to investigate particle size distribution, particle concentration and shape in hydraulic liquid in order to implement the proactive maintenance of hydraulic equipment. The existing instruments such as automatic particle counters and techniques are not sufficiently enough to address this task because of their restricted sensitivity, limit of concentration to be measured and they cannot determine particle shape. Other instruments cannot be used as inline sensors because they are not resistant to the arduous conditions such as high pressure and vibration. The novel mathematical model was proposed as it is not possible to use previously developed techniques based on using optical system and complicated algorithms. This model gives the output signal of the image sensor depending on the particle size, its distance from the light source (LED) and image sensor. Additionally, the model takes into account the limited exposure time and particle track simulation. The results of simulation based on the model are also performed in thesis. On the basis of the mathematical model the image processing algorithms were suggested in order to determine particle size even when this size is lower than pixel size. There are different approaches depending on the relation between the size of the particle and the pixel size. The approach to the volume of liquid sample estimation was suggested in order to address the problem of low accuracy of concentration measurement by the conventional automatic particle counters based on the single photodiode. Proposed technique makes corrections on the basis of particle velocity estimation. Approach to the accuracy estimation of the sensor was proposed and simulation results are shown. Generally, the accuracy of particle size and concentration measurement was considered. Ultimately, the experimental setup was used in order to test suggested techniques. The mathematical model was tested and the results showed sufficient correlation with the experiment. The zinc dust was used as a reference object as there are the particles within the range from 1 to 25 microns which is appropriate to check the sensitivity. The results of experiments using reference instrument showed the improved sensitivity and accuracy of volume measured compared to the reference one.
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Axelsson, Patrik. "Sensor Fusion and Control Applied to Industrial Manipulators." Doctoral thesis, Linköpings universitet, Reglerteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-105343.
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One of the main tasks for an industrial robot is to move the end-effector in a predefined path with a specified velocity and acceleration. Different applications have different requirements of the performance. For some applications it is essential that the tracking error is extremely small, whereas other applications require a time optimal tracking. Independent of the application, the controller is a crucial part of the robot system. The most common controller configuration uses only measurements of the motor angular positions and velocities, instead of the position and velocity of the end-effector. The development of new cost optimised robots has introduced unwanted flexibilities in the joints and the links. The consequence is that it is no longer possible to get the desired performance and robustness by only measuring the motor angular positions. This thesis investigates if it is possible to estimate the end-effector position using Bayesian estimation methods for state estimation, here represented by the extended Kalman filter and the particle filter. The arm-side information is provided by an accelerometer mounted at the end-effector. The measurements consist of the motor angular positions and the acceleration of the end-effector. In a simulation study on a realistic flexible industrial robot, the angular position performance is shown to be close to the fundamental Cramér-Rao lower bound. The methods are also verified in experiments on an ABB IRB4600 robot, where the dynamic performance of the position for the end-effector is significantly improved. There is no significant difference in performance between the different methods. Instead, execution time, model complexities and implementation issues have to be considered when choosing the method. The estimation performance depends strongly on the tuning of the filters and the accuracy of the models that are used. Therefore, a method for estimating the process noise covariance matrix is proposed. Moreover, sampling methods are analysed and a low-complexity analytical solution for the continuous-time update in the Kalman filter, that does not involve oversampling, is proposed. The thesis also investigates two types of control problems. First, the norm-optimal iterative learning control (ILC) algorithm for linear systems is extended to an estimation-based norm-optimal ILC algorithm where the controlled variables are not directly available as measurements. The algorithm can also be applied to non-linear systems. The objective function in the optimisation problem is modified to incorporate not only the mean value of the estimated variable, but also information about the uncertainty of the estimate. Second, H∞ controllers are designed and analysed on a linear four-mass flexible joint model. It is shown that the control performance can be increased, without adding new measurements, compared to previous controllers. Measuring the end-effector acceleration increases the control performance even more. A non-linear model has to be used to describe the behaviour of a real flexible joint. An H∞-synthesis method for control of a flexible joint, with non-linear spring characteristic, is therefore proposed.En av de viktigaste uppgifterna för en industrirobot är att förflytta verktyget i en fördefinierad bana med en specificerad hastighet och acceleration. Exempel på användningsområden för en industrirobot är bland annat bågsvetsning eller limning. För dessa typer av applikationer är det viktigt att banföljningsfelet är extremt litet, men även hastighetsprofilen måste följas så att det till exempel inte appliceras för mycket eller för lite lim. Andra användningsområden kan vara punktsvetsning av bilkarosser och paketering av olika varor. För dess applikationer är banföljningen inte det viktiga, istället kan till exempel en tidsoptimal banföljning krävas eller att svängningarna vid en inbromsning minimeras. Oberoende av applikationen är regulatorn en avgörande del av robotsystemet. Den vanligaste regulatorkonfigurationen använder bara mätningar av motorernas vinkelpositioner och -hastigheter, istället för positionen och hastigheten för verktyget, som är det man egentligen vill styra. En del av utvecklingsarbetet för nya generationers robotar är att reducera kostnaden men samtidigt förbättra prestandan. Ett sätt att minska kostnaden kan till exempel vara att minska dimensionerna på länkarna eller köpa in billigare växellådor. Den här utvecklingen av kostnadsoptimerade robotar har infört oönskade flexibiliteter i leder och länkar. Det är därför inte längre möjligt att få den önskade prestandan och robustheten genom att bara mäta motorernas vinkelpositioner och -hastigheter. Istället krävs det omfattande matematiska modeller som beskriver dessa oönskade flexibiliteter. Dessa modeller kräver mycket arbete att dels ta fram men även för att identifiera parametrarna. Det finns automatiska metoder för att beräkna modellparametrarna men oftast krävs det en manuell justering för att få bra prestanda. Den här avhandlingen undersöker möjligheterna att beräkna verktygspositionen med hjälp av bayesianska metoder för tillståndsskattning. De bayesianska skattningsmetoderna beräknar tillstånden för ett system iterativt. Med hjälp av en matematisk modell över systemet predikteras vad tillståndet ska vara vid nästa tidpunkt. Efter att mätningar av systemet vid den nya tidpunkten har genomförts justeras skattningen med hjälp av dessa mätningar. De metoder som har använts i avhandlingen är det så kallade extended Kalman filtret samt partikelfiltret. Informationen på armsidan av växellådan ges av en accelerometer som är monterad på verktyget. Med hjälp av accelerationen för verktyget och motorernas vinkelpositioner kan en skattning av verktygspositionen beräknas. I en simuleringsstudie för en realistisk vek robot har det visats att skattningsprestandan ligger nära den teoretiska undre gränsen, känd som Raooch mätstörningar som påverkar roboten. För att underlätta trimningen så har en metod för att skatta processbrusets kovariansmatris föreslagits. En annan viktig del som påverkar prestandan är modellerna som används i filtren. Modellerna för en industrirobot är vanligtvis framtagna i kontinuerlig tid medan filtren använder modeller i diskret tid. För att minska felen som uppkommer då de tidskontinuerliga modellerna överförs till diskret tid har olika samplingsmetoder studerats. Vanligtvis används enkla metoder för att diskretisera vilket innebär problem med prestanda och stabilitet. För att hantera dessa problem införs översampling vilket innebär att tidsuppdateringen sker med en mycket kortare sampeltid än vad mätuppdateringen gör. För att undvika översampling kan det motsvarande tidskontinuerliga filtret användas för att prediktera tillstånden vid nästa diskreta tidpunkt. En analytisk lösning med låg beräkningskomplexitet till detta problem har föreslagits. Vidare innehåller avhandlingen två typer av reglerproblem relaterade till industrirobotar. För det första har den så kallade norm-optimala iterative learning control styrlagen utökats till att hantera fallet då en skattning av den önskade reglerstorheten används istället för en mätning. Med hjälp av skattningen av systemets tillståndsvektor kan metoden nu även användas till olinjära system vilket inte är fallet med standardformuleringen. Den föreslagna metoden utökar målfunktionen i optimeringsproblemet till att innehålla inte bara väntevärdet av den skattade reglerstorheten utan även skattningsfelets kovariansmatris. Det innebär att om skattningsfelet är stort vid en viss tidpunkt ska den skattade reglerstorheten vid den tidpunkten inte påverka resultatet mycket eftersom det finns en stor osäkerhet i var den sanna reglerstorheten befinner sig. För det andra har design och analys av H∞-regulatorer för en linjär modell av en vek robotled, som beskrivs med fyra massor, genomförts. Det visar sig att reglerprestandan kan förbättras, utan att lägga till fler mätningar än motorns vinkelposition, jämfört med tidigare utvärderade regulatorer. Genom att mäta verktygets acceleration kan prestandan förbättras ännu mer. Modellen över leden är i själva verket olinjär. För att hantera detta har en H∞-syntesmetod föreslagits som kan hantera olinjäriteten i modellen.
Vinnova Excellence Center LINK-SIC
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Wallin, Jonas, and Joakim Zachrisson. "Sensor Fusion in Smartphones : with Application to Car Racing Performance Analysis." Thesis, Linköpings universitet, Reglerteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-94170.
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Today's smartphones are equipped with a variety of different sensors such as GPS receivers, accelerometers, gyroscopes and magnetometers, making smartphones viable tools in many applications. The computational capacity of smartphones allows for software applications running advanced signal processing algorithms. Thus, attaching a smartphone inside a car makes it possible to estimate kinematics of the vehicle by fusing information from the different sensors inside the smartphone. Fusing information from different sources for improving estimation quality is a well-known problem and there exist a lot of methods and algorithms in this area. This thesis approaches the sensor fusion problem of estimating kinematics of cars using smartphones for the purpose of analysing driving performance. Different varieties of the coordinated turn model for describing the vehicle dynamics are investigated. Also, different measurement models are evaluated where bias errors of the sensors are taken into consideration. Pre-filtering and construction of pseudo-measurements are also considered which allow for use of state space models with a lower dimension.Dagens smartphones är utrustade med en rad olika typer av sensorer såsom GPS mottagare, accelerometrar, gyroskop och magnetometrar vilket medför ett stort användningsområde. Beräkningskapaciteten hos smartphones gör det möjligt för mjukvaruapplikationer att använda sig av avancerade algoritmer för signalbehandling. Det är därför möjligt att placera en smartphone inuti en bil och skatta bilens kinematik genom att kombinera informationen från de olika sensorerna. Att fusionera information från olika källor för att erhålla bättre skattningar är ett välkänt område där det finns många metoder och algoritmer utvecklade. Detta examensarbete behandlar sensorfusionsproblemet att skatta bilars kinematik med hjälp av smartphones för syftet att kunna analysera körprestanda. Olika varianter av en coordinated turn modell för att beskriva bilens dynamik undersöks. Dessutom testas olika modeller för sensorerna där hänsyn till exempelvis biasfel tas. Förbehandling av data och pseudomätningar testas också vilket gör det möjligt att använda tillståndsmodeller med låg dimension.
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Li, Zeyuan. "Target localization using RSS measurements in wireless sensor networks." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31356.
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The subject of this thesis is the development of localization algorithms for target localization in wireless sensor networks using received signal strength (RSS) measurements or Quantized RSS (QRSS) measurements. In chapter 3 of the thesis, target localization using RSS measurements is investigated. Many existing works on RSS localization assumes that the shadowing components are uncorrelated. However, here, shadowing is assumed to be spatially correlated. It can be shown that localization accuracy can be improved with the consideration of correlation between pairs of RSS measurements. By linearizing the corresponding Maximum Likelihood (ML) objective function, a weighted least squares (WLS) algorithm is formulated to obtain the target location. An iterative technique based on Newtons method is utilized to give a solution. Numerical simulations show that the proposed algorithms achieves better performance than existing algorithms with reasonable complexity. In chapter 4, target localization with an unknown path loss model parameter is investigated. Most published work estimates location and these parameters jointly using iterative methods with a good initialization of path loss exponent (PLE). To avoid finding an initialization, a global optimization algorithm, particle swarm optimization (PSO) is employed to optimize the ML objective function. By combining PSO with a consensus algorithm, the centralized estimation problem is extended to a distributed version so that can be implemented in distributed WSN. Although suboptimal, the distributed approach is very suitable for implementation in real sensor networks, as it is scalable, robust against changing of network topology and requires only local communication. Numerical simulations show that the accuracy of centralized PSO can attain the Cramer Rao Lower Bound (CRLB). Also, as expected, there is some degradation in performance of the distributed PSO with respect to the centralized PSO. In chapter 5, a distributed gradient algorithm for RSS based target localization using only quantized data is proposed. The ML of the Quantized RSS is derived and PSO is used to provide an initial estimate for the gradient algorithm. A practical quantization threshold designer is presented for RSS data. To derive a distributed algorithm using only the quantized signal, the local estimate at each node is also quantized. The RSS measurements and the local estimate at each sensor node are quantized in different ways. By using a quantization elimination scheme, a quantized distributed gradient method is proposed. In the distributed algorithm, the quantization noise in the local estimate is gradually eliminated with each iteration. Simulations show that the performance of the centralized algorithm can reach the CRLB. The proposed distributed algorithm using a small number of bits can achieve the performance of the distributed gradient algorithm using unquantized data.
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Ma, Aihui. "Synthesis and characterization of miniaturized fluorescence sensors for aqueous and cellular measurements." ScholarWorks@UNO, 2005. http://louisdl.louislibraries.org/u?/NOD,240.
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Thesis (Ph. D.)--University of New Orleans, 2005.Title from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Chemistry."--Dissertation t.p. Vita. Includes bibliographical references.
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Zhang, Feng Hong. "A novel optical fibre sensor based on inter-fibre distributed coupling for particle concentration measurement." Thesis, Liverpool John Moores University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361510.
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Chen, Zongde. "Depleted CMOS sensor development for pixel particle detectors under high intensity and high radiative dose." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0430.
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Le trajectographe interne (ITk) de l'expérience ATLAS sera amélioré pour la nouvelle phase de prise de données du grand collisionneur de hadrons du CERN à haute luminosité (HL-LHC) en 2026. Le HL-LHC fonctionnera avec l’énergie nominale de collision est de 14 TeV et la luminosité instantanée maximale de 7,5 x (10)34 cm(−2) s(−1), cinq fois plus élevée qu’à présent. La luminosité accrue se traduira par des niveaux de rayonnement et des débits de données environ dix fois plus élevés. Afin de faire face aux exigences d’ATLAS en termes d’intensite du rayonnement, de vitesse de lecture et de granularité au HL-LHC, le remplacement de l’actuel ATLAS Inner Tracker (ITk) est nécessaire. Deux capteurs CMOS épuisés à grande échelle dans la technologie LF de 150 nm, appelés LF-CPIX et LF-MONOPIX, ont été développés dans le cadre de la mise à niveau ATLAS Inner Tracker (ITK) pour le LHC à haute luminosité. Le travail présenté ici montre la caractérisation de ces trois prototypes, avec des contributions concernant le développement de la configuration, le calibrage source 55 Fe et 90 Sr, les modifications du microprogramme FPGA et le développement de programmes de test. L’enquête sur la dureté du rayonnement pour l’électronique et les composants du capteur a été une préoccupation majeure. Nous montrerons les résultats concernant les caractérisations de ces prototypes dans les performances de laboratoire du CPPM, ainsi que les résultats de multiples campagnes de rayonnement conduites à l’installation de protons IRRAD de 24 GeV du CERN, afin d’étudier les effets de la perte d’énergie non ionisante (NIEL) et du Dose ionisante (TID) sur les prototypesThe Inner Tracker (ITk) system of the ATLAS experiment will be upgraded for the 2026 High Luminosity Large Hadron Collider (HL-LHC) run. The HL-LHC will operate with a center of mass energy of 14 TeV and a peak instantaneous luminosity five times higher than at present. The increased luminosity will result in roughly ten times higher radiation levels and data rates. To cope with the ATLAS requirements in terms of radiation hardness, readout speed and granularity at the HL-LHC, the replacement of the present ATLAS Inner Tracker (ITk) is needed. Two large-scale depleted CMOS sensors in the 150 nm LF-technology called LF-CPIX and LF-MONOPIX, developed in the framework of the ATLAS Inner Tracker (ITK) upgrade for High Luminosity LHC. The work presented here shows the characterization for these three prototypes, with contributions concerning the setup development, 55Fe and 90Sr source calibration, modifications of the FPGA firmware and development of test programs. A main concern was the investigation on the radiation hardness for both the electronics and the sensor parts. We will show results concerning characterizations for these prototypes in the laboratory performance at CPPM, as well as results in multiple radiation campaigns performed at the 24 GeV IRRAD proton facility at CERN, to study the effects of Non-Ionizing Energy Loss (NIEL) and Total Ionizing Dose (TID) on the prototypes
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Jiang, Bo. "Energy Efficient Target Tracking in Wireless Sensor Networks: Sleep Scheduling, Particle Filtering, and Constrained Flooding." Diss., Virginia Tech, 2010. http://hdl.handle.net/10919/29963.
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Energy efficiency is a critical feature of wireless sensor networks (WSNs), because sensor nodes run on batteries that are generally difficult to recharge once deployed. For target tracking---one of the most important WSN application types---energy efficiency needs to be considered in various forms and shapes, such as idle listening, trajectory estimation, and data propagation. In this dissertation, we study three correlated problems on energy efficient target tracking in WSNs: sleep scheduling, particle filtering, and constrained flooding.
We develop a Target Prediction and Sleep Scheduling protocol (TPSS) to improve energy efficiency for idle listening. We start with designing a target prediction method based on both kinematics and probability. Based on target prediction and proactive wake-up, TPSS precisely selects the nodes to awaken and reduces their active time, so as to enhance energy efficiency with limited tracking performance loss. In addition, we expand Sleep Scheduling to Multiple Target Tracking (SSMTT), and further reduce the energy consumption by leveraging the redundant alarm messages of interfering targets. Our simulation-based experimental studies show that compared to existing protocols such as Circle scheme and MCTA, TPSS and SSMTT introduce an improvement of 25% ~ 45% on energy efficiency, at the expense of only 5% ~ 15% increase on the detection delay.
Particle Filtering is one of the most widely used Bayesian estimation methods, when target tracking is considered as a dynamic state estimation problem for trajectory estimation. However, the significant computational and communication complexity prohibits its application in WSNs. We design two particle filters (PFs)---Vector space based Particle Filter (VPF) and Completely Distributed Particle Filter (CDPF)---to improve energy efficiency of PFs by reducing the number of particles and the communication cost. Our experimental evaluations show that even though VPF incurs 34% more estimation error than RPF, and CDPF incurs a similar estimation error to SDPF, they significantly improve the energy efficiency by as much as 68% and 90% respectively.
For data propagation, we present a Constrained Flooding protocol (CFlood) to enhance energy efficiency by increasing the deadline satisfaction ratio per unit energy consumption of time-sensitive packets. CFlood improves real-time performance by flooding, but effectively constrains energy consumption by controlling the scale of flooding---i.e., flooding only when necessary. If unicasting meets the distributed sub-deadline at a hop, CFlood aborts further flooding even after flooding has occurred in the current hop. Our simulation-based experimental studies show that CFlood achieves higher deadline satisfaction ratio per unit energy consumption by as much as 197%, 346%, and 20% than existing multipath forwarding protocols, namely, Mint Routing, MCMP and DFP respectively, especially in sparsely deployed or unreliable sensor network environments.
To verify the performance and efficiency of the dissertation's solutions, we developed a prototype implementation based on TelosB motes and TinyOS version 2.1.1. In the field experiments, we compared TPSS, VPF, CDPF, and CFlood algorithms/protocols to their respective competing efforts. Our implementation measurements not only verified the rationality and feasibility of the proposed solutions for target tracking in WSNs, but also strengthened the observations on their efficiency from the simulation.Ph. D.
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Caulk, Jeffrey V. "Experimental and theoretical performance of a particle velocity vector sensor in a hybrid acoustic beamformer." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FCaulk.pdf.
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Thesis (M.S. in Engineering Acoustics)--Naval Postgraduate School, December 2009.Thesis Advisor(s): Kapolka, Daphne ; Smith, Kevin B. "December 2009." Description based on title screen as viewed on January 29, 2010. Author(s) subject terms: Particle velocity, beamforming, beam pattern, acoustic array, acoustic vector sensor, Microflown, hybrid array, frequency spectrum, linear array, directional. Includes bibliographical references (p. 151-153). Also available in print.
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MERICO, DAVIDE. "Tracking with high-density, large-scale wireless sensor networks." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2010. http://hdl.handle.net/10281/7785.
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Given the continuous technological advances in computing and communication, it seems that we are rapidly heading towards the realization of paradigms commonly described as ubiquitous computing, pervasive computing, ambient intelligence, or, more recently, "everyware". These paradigms envision living environments pervaded by a high number of invisible technological devices affecting and improving all aspects of our lives. Therefore, it is easy to justify the need of knowing the physical location of users. Outdoor location-aware applications are already widespread today, their growing popularity showing that location-awareness is indeed a very useful functionality.
Less obvious is how the growing availability of these locations and tracks will be exploited for providing more intelligent "situation-understanding" services that help people.
My work is motivated by the fact that, thanks to location-awareness systems, we are more and more aware of the exact positions of the users but unfortunately we are rarely capable of exactly understanding what they are doing. Location awareness should rapidly evolve and become "situation-awareness" otherwise the ubiquitous-computing vision will become impracticable.
The goal of this thesis is devising alternative and innovative approaches to the problem of indoor position estimation/assessment and evaluating them in real environments. These approaches are be based on: (i) a low-cost and energy-aware localization infrastructure; (ii) multi-sensor, statistically-based, localization algorithms; (iii) logic-based situation assessment techniques.
The algorithms and techniques that are the outcome of this thesis have all been tested by implementing them and measuring (both in a quantitative sense and in a qualitative sense) the performance in the field.
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Chaychian, Sara. "Magnetic DNA detection sensor for point-of-care diagnostics." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/11496.
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This thesis focuses on inductive base sensor design at MHz range frequency. The background theory, design, experiments and results for a new magnetic particles sensor is presented. A new magnetic sensor based on a planar coil was investigated for DNA pathogen detection. Change in inductance of the planar coil due to the presence of magnetic particles with varying mass was measured. The experimental set-up consisted of different sized planar coil with associated electronics for inductance measurements. The best sensor performance was accomplished using two different inductors while oscillating at frequencies 2.4MHz using 9.5μH inductor and 7.2MHz with 85μH inductor. The sensor has very large signal to noise ratio (580×103), while the average amount of frequency drift was 0.58. This sensor was tested with various types of magnetic particles. In addition, iron-oxide nanoparticles were synthesized through water in oil microemulsion method and with an average size of 25nm. The best sensitivity achieved for detection of 50μg iron-oxide particles was with the bead size of 10nm. 81Hz frequency shift was attained in regard to that amount of particles. This research shows that increasing the resonance frequency to 7.2MHz can cause the larger output signal difference (frequency shift) in the presence of magnetic particles; however, the sensor stability is the most important factor for determining the detection resolution and sensitivity. The sensitivity is better if the sensor can detect smaller amount of magnetic sample. The results of this research demonstrate that while the sample consists of smaller size particles, the sensor can detect the lower amount of sample. This is due to the heating effect of nanoparticles. On the other hand the sample distance from the sensor has a major impact on the sensitivity too; the shorter the distance, the higher the sensitivity. This technique can potentially be extended to detect several different types of bacterial pathogens and can be modified for multiplex quantitative detection. This sensing technique will be incorporated into a handheld, disposable microfluidic chip for point-of-care diagnostics for sexually transmitted diseases.
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Hu, Kai. "Solving Inverse Problems Using Particle Swarm Optimization: An Application to Aircraft Fuel Measurement Considering Sensor Failure." Cincinnati, Ohio : University of Cincinnati, 2006. http://www.ohiolink.edu/etd/view.cgi?acc%5Fnum=ucin1141398269.
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Thesis (M.S.)--University of Cincinnati, 2006.Title from electronic thesis title page (viewed Apr. 19, 2006). Includes abstract. Keywords: Inverse Problem, Particle Swarm Optimization, Neural Networks, Aircraft Fuel Measurement, Sensor Failure Includes bibliographical references.
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Moemeni, Armaghan. "Hybrid marker-less camera pose tracking with integrated sensor fusion." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/11093.
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This thesis presents a framework for a hybrid model-free marker-less inertial-visual camera pose tracking with an integrated sensor fusion mechanism. The proposed solution addresses the fundamental problem of pose recovery in computer vision and robotics and provides an improved solution for wide-area pose tracking that can be used on mobile platforms and in real-time applications. In order to arrive at a suitable pose tracking algorithm, an in-depth investigation was conducted into current methods and sensors used for pose tracking. Preliminary experiments were then carried out on hybrid GPS-Visual as well as wireless micro-location tracking in order to evaluate their suitability for camera tracking in wide-area or GPS-denied environments. As a result of this investigation a combination of an inertial measurement unit and a camera was chosen as the primary sensory inputs for a hybrid camera tracking system. After following a thorough modelling and mathematical formulation process, a novel and improved hybrid tracking framework was designed, developed and evaluated. The resulting system incorporates an inertial system, a vision-based system and a recursive particle filtering-based stochastic data fusion and state estimation algorithm. The core of the algorithm is a state-space model for motion kinematics which, combined with the principles of multi-view camera geometry and the properties of optical flow and focus of expansion, form the main components of the proposed framework. The proposed solution incorporates a monitoring system, which decides on the best method of tracking at any given time based on the reliability of the fresh vision data provided by the vision-based system, and automatically switches between visual and inertial tracking as and when necessary. The system also includes a novel and effective self-adjusting mechanism, which detects when the newly captured sensory data can be reliably used to correct the past pose estimates. The corrected state is then propagated through to the current time in order to prevent sudden pose estimation errors manifesting as a permanent drift in the tracking output. Following the design stage, the complete system was fully developed and then evaluated using both synthetic and real data. The outcome shows an improved performance compared to existing techniques, such as PTAM and SLAM. The low computational cost of the algorithm enables its application on mobile devices, while the integrated self-monitoring, self-adjusting mechanisms allow for its potential use in wide-area tracking applications.
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Barboza, Kris Leo. "A Diagnostic Technique for Particle Characterization Using Laser Light Extinction." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/52000.
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Increased operations of aircraft, both commercial and military, in hostile desert environments have increased risks of micro-sized particle ingestion into engines. The probability of increased sand and dust ingestion results in increased life cycle costs, in addition to increased potential for performance loss. Thus, abilities to accurately characterize inlet sand would be useful for engine diagnostics and prognostic evaluation. Previous characterization studies were based on particle measurements performed a posteriori. Thus, there exists a need for in situ quantification of ingested particles.
The work presented in this thesis describes initial developments of a line-of-sight optical technique to characterize ingested particles at concentrations similar to those experienced by aircraft in brownout conditions using light extinction with the end goal of producing an onboard aircraft diagnostic sensor. By measuring the extinct light intensity in presence of particles over range of concentrations, a relationship between diameters, concentration and light extinction was used for characterization. The particle size distribution was assumed log-normal and size range of interest 1-10 μm.
To validate the technique, particle characterization in both static and flow based tests were performed on polystyrene latex spheres of sizes 1.32 μm, 3.9 μm, 5.1 μm, and 7 μm in mono-disperse and poly-disperse mixtures. Results from the static experiments were obtained with a maximum relative error of 11%. Concentrations from the static experiments were obtained with a maximum relative error of 18%. Mono-dispersed and poly-dispersed particle samples were sized in a flow setup, with a maximum relative error of 12% and 10% respectively across all diameter samples tested. Uncertainty in measurements were quantified, with results indicating a maximum error of 17% in diameters due to sources of variability and showed that shorter wavelength lasers provide lower errors in concentration measurements, compared to longer wavelengths.
For real time, on-board measurements, where path lengths traveled by light are much larger than distances traveled in initial proof of concept experimental setups, requirements would be to install sensitive detectors and powerful lasers to prevent operation near noise floors of detectors. Vibration effects from the engine can be mitigated by using larger area collection optics to ensure that the transmitted light falls on active detector areas.
Results shown in this thesis point towards validity of the light extinction technique to provide real time characterization of ingested particles, and will serve as an impetus to carry out further research using this technique to characterize particles entering aircraft engine inlets.Master of Science
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Wan, Wei. "Molecularly imprinted chromogenic and fluorogenic receptors as optical sensor matrix." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2015. http://dx.doi.org/10.18452/17261.
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Diese Dissertation befasste sich mit der Entwicklung von optischen Sensormaterialien für anionische Zielmoleküle durch die Kopplung der herausragenden Erkennungsfähigkeiten von molekular geprägten Polymere (molecularly imprinted polymers, MIPs) mit der Empfindlichkeit fluorometrischer Nachweisverfahren. In dieser Arbeit wurde dabei der direkte Einschritt-Nachweis für das Design der Sensormaterialien adaptiert. Hierbei wird eine Fluoreszenzsonde für die Signalübertragung kovalent in die Hohlräume der MIP-Matrix eingebaut. MIP-Sensormaterialien wurde in monolithischen, Dünnfilm- und Kern/Schale-Partikel-Formaten hergestellt. Die hergestellten Materialien wurden unter Verwendung unterschiedlicher Techniken charakterisiert. Die Performanz der Sensormaterialien wurde auch in Bezug auf die Sensitivität, Selektivität sowie Ansprechzeit bewertet. In dieser Arbeit wurden dabei Systeme untersucht, bei denen die Signalerzeugung sowohl auf dem „Einschalten“ als auch auf dem „Ausschalten“ der Fluoreszenz beruhte. Mit den hergestellten Materialien wurden dabei viele Ziele des Projekts erreicht. Sowohl die synthetisierten dünnen Filme als auch die Kern/Schale-Partikel zeigten eine hohe Selektivität für die geprägten Aminosäuren, auch in Bezug auf die Unterscheidung von Enantiomeren. Diese Sensormaterialien waren ebenfalls durch eine niedrige Nachweisgrenze bis 60 µM und eine schnelle Ansprechzeit von 20 Sekunden gekennzeichnet. Insbesondere die Kern/Schale-Partikel können mit verschiedenen Detektionstechniken gekoppelt werden und sind potentiell für die Entwicklung von miniaturisierten Messinstrumenten für die on-line-Detektion sowie Point-of-Care-Diagnostik (patientennahe Labordiagnostik) einsetzbar.This dissertation derives from the DFG project aimed on preparing optical sensor material for anionic target through combing the outstanding recognition of Molecularly imprinted polymer (MIPs) and sensitive fluorescence technique. A single step direct sensing strategy is adopted to prepare the sensor material in this thesis. Here, a fluorescence probe is covalently embedded into the MIP cavity for signal transduction. MIP sensor material are prepared in forms of bulk, thin film and particles. The material is characterized using various techniques. The performance of the sensor materials is also assessed in terms of sensibility, selectivity as well response time. Both the switching on and off signaling methods are tested in this thesis. The prepared material achieves the goal of the project. Both the prepared thin film as well as core-shell particle show prominent selectivity even a strong enantioselective discrimination. These sensing materials also have low LOD to 60 µM and fast sensing response of 20 seconds. Especially the core-shell sensing particle can be coupled with various detection techniques and is potentially applicable for developing miniaturized sensing instrument for on-line detection as well as point of care diagnose.
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Benítez, Casma Víctor Hugo. "Design, fabrication and characterization of semiconductor radiation sensors for future high energy physics experiments." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/666717.
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Aquest treball se centra en els sensors de radiació de silici, especialment en el disseny, la fabricació i la caracterització dels sensors de microstrip per a experiments en física d'alta energia. La creació de prototips per a l'actualització del detector ATLAS (sensors Petalet) i la proposta d'una estructura de protecció contra pèrdues de feix (sensors LowR) són el marc de les activitats de recerca. A causa de les complexes geometries dels prototips a construir, es va desenvolupar una eina de software semiautomàtic en Python per reduir el temps de disseny de les màscares i elaborar tots els dissenys de màscares necessaris per als passos fotolitogràfics. Aquesta eina de software es va utilitzar juntament amb software industrial estàndard per a les dues activitats de recerca. La tecnologia base considerada és el procés CMOS estàndard al IMB-CNM, que ja ha produït sensors de radiació de silici en el passat. Es van necessitar modificacions de la tecnologia base per complir els requisits dels prototips, com l'augment de l'òxid entre la implantació del strip i el metall de lectura per disminuir la capacitat de acoblament i augmentar la seva tensió de rupture, o una capa metàl·lica addicional que incloïa adaptadors encastats per a un millor contacte amb lelectrònica. Es van necessitar més modificacions per a les estructures de protecció proposades, com els òxids de diverses capes dipositades a baixa temperatura sobre el metall de lectura, o utilitzar polisilici d'alta densitat com a alternativa per reduir la resistivitat del strip. Les estructures de prova també es van dissenyar i fabricar per realitzar proves elèctriques i òptiques durant el procés de fabricació i abans que es tallessin els sensors, com a part d'un programa de verificació complet. Els sensors fabricats es van caracteritzar elèctricament i es van enviar als instituts de col·laboració per fer-ne més proves. Els sensors Petalet també van ser transportats a Freiburg, Alemanya per muntatge elèctric i mecànic amb electrònica de lectura i es van realitzar proves a nivell de detector. Els sensors LowR van ser transportats a Santa Cruz, EUA per realitzar una simulació dinàmica de la pèrdua de feix mitjançant un làser centrat i verificar l'efectivitat de la solució proposada.This work focuses on silicon radiation sensors, particularly on the design, fabrication and characterization of microstrips sensors for high energy physics experiments. Building prototypes for the ATLAS detector upgrade (Petalet sensors) and the proposal of a protection structure against beam losses (LowR sensors) are the framework for the research activities. Due to the complex geometries of the prototypes to be built, a semi-automatic software tool was developed in Python to reduce mask design time and elaborate all the required mask layouts for the photolithographic steps. This software tool was used together with standard industrial software for both research activities. The baseline technology considered is the standard CMOS process at IMB-CNM, which has already produced silicon radiation sensors in the past. Modifications of the baseline technology were needed to fulfil the requirements of the prototype sensors, such as increase of the oxide between strip implant and read-out metal to decrease the coupling capacitance and increase its breakdown voltage, or an additional metal layer to included embedded pitch adaptors for better wire bonding. Further modifications were needed for the proposed protection structures, such as low temperature deposited multi-layer oxides on top of read-out metal, or use high-density polysilicon as an alternative to reduce the strip resistivity. Test structures were also designed and fabricated to perform electrical and optical tests during the fabrication process and before the sensors were cut, as part of a full verification program. The fabricated sensors were fully electrically characterized and delivered to collaboration institutes for further testing. The Petalet sensors were also taken to Freiburg, Germany for mechanical an electrical assembly with read-out electronics and detector level tests were performed. The LowR sensors were taken to Santa Cruz, USA to perform dynamic simulation of a beam loss by using a focussed laser and to verify the effectiveness of the proposed solution.
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Baradwaj, Nithin V. "Uncertainty Analysis of Resistive Soot Sensors for On-BoardDiagnostics of Automotive Particulate Filters." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1376408721.
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Al-Olimat, Hussein S. "Optimizing Cloudlet Scheduling and Wireless Sensor Localization using Computational Intelligence Techniques." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1403922600.
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Al-Obaidi, Mohanad. "ENAMS : energy optimization algorithm for mobile wireless sensor networks using evolutionary computation and swarm intelligence." Thesis, De Montfort University, 2010. http://hdl.handle.net/2086/5187.
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Although traditionally Wireless Sensor Network (WSNs) have been regarded as static sensor arrays used mainly for environmental monitoring, recently, its applications have undergone a paradigm shift from static to more dynamic environments, where nodes are attached to moving objects, people or animals. Applications that use WSNs in motion are broad, ranging from transport and logistics to animal monitoring, health care and military. These application domains have a number of characteristics that challenge the algorithmic design of WSNs. Firstly, mobility has a negative effect on the quality of the wireless communication and the performance of networking protocols. Nevertheless, it has been shown that mobility can enhance the functionality of the network by exploiting the movement patterns of mobile objects. Secondly, the heterogeneity of devices in a WSN has to be taken into account for increasing the network performance and lifetime. Thirdly, the WSN services should ideally assist the user in an unobtrusive and transparent way. Fourthly, energy-efficiency and scalability are of primary importance to prevent the network performance degradation. This thesis contributes toward the design of a new hybrid optimization algorithm; ENAMS (Energy optimizatioN Algorithm for Mobile Sensor networks) which is based on the Evolutionary Computation and Swarm Intelligence to increase the life time of mobile wireless sensor networks. The presented algorithm is suitable for large scale mobile sensor networks and provides a robust and energy- efficient communication mechanism by dividing the sensor-nodes into clusters, where the number of clusters is not predefined and the sensors within each cluster are not necessary to be distributed in the same density. The presented algorithm enables the sensor nodes to move as swarms within the search space while keeping optimum distances between the sensors. To verify the objectives of the proposed algorithm, the LEGO-NXT MIND-STORMS robots are used to act as particles in a moving swarm keeping the optimum distances while tracking each other within the permitted distance range in the search space.
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Davis, Joseph P. "Electronic Interface for an Inductive Wear Debris Sensor for Detection of Ferrous and Non-Ferrous Particles." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1380998832.
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Kendler, Johnathan M. "Evaluating methods for implementing photogrammetric sensor platforms with various Lidar components for use with close and mid-range particle detection systems." abstract and full text PDF (UNR users only), 2008. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:1460763.
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Swanepoel, Francois. "Estimation of particle size distributions in mineral process systems using acoustic techniques." Thesis, Stellenbosch : Stellenbosch University, 2000. http://hdl.handle.net/10019.1/51746.
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Thesis (MEng)--Stellenbosch University, 2000.ENGLISH ABSTRACT: A desire to increase the efficiency of the comminution process in mineral process systems has led to the need of determining the size distribution of ore particles at various stages in the system. The objective of this research is to investigate the feasibility of the use of an acoustic sensor for measuring particle size distribution. The acoustic signal generated when the particles impact on a cantilever bar is analysed using digital signal processing techniques. As rocks fall onto a metal bar, the bar vibrates. The vibrations contain information th a t is extracted to determine the size of particles tha t impacted on the bar. The bar is modelled as a linear system which is excited by impulses (impact of particles). The response of the bar is deconvolved from the acoustic signal to obtain an impulse whose amplitude is proportional to the energy of the impact. In order to improve size estimates, deconvolution is performed using a statistical model of the impulse sequence (Bernoulli-Gaussian) and then estimated using MAP estimation. Size estimates are not only a function of the mass of particles, but also on the exact position of impact on the bar. Since there is always a variation in the position of impact, size estimates are erroneous. It was found that the position of impact can be determined as to reduce variances dramatically. Due to physical sampling in space, the sensor has a bias towards larger particles. We show how this can be represented mathematically and removed. This project is mainly concerned with rocks in the +8-25mm (+0,7-22 gram) size range.
AFRIKAANSE OPSOMMING: Vergruising van erts in die mineraalbedryf verg groot hoeveelhede energie. Daar is ’n behoefte gei'dentifiseer orn hierdie proses meer effektief te maak. Aangesien die effektiwiteit van ’n meul ’n funksie is van die ertsgroottes wat gemaal word, kan partikel grootte inligting aangewend word om effektiwiteit te bevorder. Die doel van hierdie tesis is om die lewensvatbaarheid van ’n akoestiese sensor vir die doel van partikelgrootte estimasie, te ondersoek. Erts partikels wat val vanaf ’n vervoerband op ’n kantelbalk, veroorsaak dat die balk vibreer. Deur hierdie vibrasies te meet en verwerk, kan inligting aangaande partikel grootte verkry word. Die stelsel word gemodelleer as ’n lineere sisteem met impulse as intree. Die geobserveerde sein is die konvolusie tussen die intree impulse en die impulsweergawe van die sisteem. Deur gebruik te maak van ’n statistiese model en MAP-estimasie, word die effek van die sisteem gedekonvuleer vanaf die geobserveerde sein om ’n benadering van die intree impuls sein te verkry. Die amplitudes van die impulse word gebruik as ’n aanduiding van partikel massa. Partikelgroottes soos benader deur die stelsel, is ’n funksie van die die posisie waar die partikel die balk tref. Deur van patroonherkenning tegnieke gebruik te maak, word die posisie van impak bepaal om sodoende grootte benaderings aan te pas en die variansie van grootte verspreidings te verminder. As gevolg van die feit dat partikels gemonster word deurdat slegs ’n klein persentasie van die hele omvang van partikels ondersoek word, onstaan daar ’n oorhelling ( “bias” ) na groter partikels. Die kans dat groter partikels die balk tref is groter as vir klein partikels. ’n Wiskundige model vir hierdie verskynsel word voorgestel en gewys hoe die die oorhelling geneutraliseer kan word. Hierdie projek het te doen met ertsgroottes +8-25mm (+0,7-22 gram).
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Zhao, Wei. "Development of CMOS sensor with digital pixels for ILD vertex detector." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAE004/document.
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La thèse présente le développement de CPS (CMOS Pixel Sensors) intégré avec CAN au niveau du pixel pour les couches externes du détecteur de vertex de l’ILD (International Large Detector). Motivé par la physique dans l’ILC (International Linear Collider), une précision élevée est nécessaire pour les détecteurs. La priorité des capteurs qui montre sur les couches externes est une faible consommation d’énergie en raison du rapport élevé de couverture de la surface sensible (~90%) dans le détecteur de vertex. Le CPS intégré avec CAN est un choix approprié pour cette application. L’architecture de CAN de niveau colonne ne fournit pas une performance optimisée en termes de bruit et la consommation d’énergie. La conception de CAN au niveau du pixel a été proposée. Bénéficiant des sorties de pixels tout-numérique, CAN au niveau des pixels présentent les mérites évidents sur le bruit, la vitesse, la zone sensible et la consommation d’énergie. Un prototype de capteur, appelé MIMADC, a été implémenté par un processus de 0.18 μm CIS (CMOS Image Sensor). L’objectif de ce capteur est de vérifier la faisabilité du CPS intégré avec les CAN au niveau des pixels. Trois matrices sont incluses dans ce prototype, mais avec deux types différents de CAN au niveau de pixel: une avec des CAN à registre à approximations successives (SAR), et les deux autres avec des CAN à une seule pente (Single-Slope, SS) CAN. Toutes les trois possédant les pixels de la même taille de 35×35 μm2 et une résolution de 3-bit. Dans ce texte, des analyses théoriques et le prototype sont présentés, ainsi que la conception détaille des circuitsThis thesis presents the development of CMOS pixel sensors (CPS) integrated with pixel-level ADCs for the outer layers of the ILD (International Large Detector) vertex detector. Driven by physics in the ILC (International Linear Collider), an unprecedented precision is required for the detectors. The priority of the sensors mounted on the outer layers is low power consumption due to the large coverage ratio of the sensitive area (~90%) in the vertex detector. The CPS integrated with ADCs is a promising candidate for this application. The architecture of column-level ADCs, exists but do not provide an optimized performance in terms of noise and power consumption. The concept of pixel-level ADCs has been proposed. Benefiting from the all-digital pixel outputs, pixel-level ADCs exhibit the obvious merits on noise, speed, insensitive area, and power consumption. In this thesis, a prototype sensor, called MIMADC, has been implemented by a 0.18 μm CIS (CMOS Image Sensor) process. The target of this sensor is to verify the feasibility of the CPS integrated with pixel-level ADCs. Three matrices are included in this prototype but with two different types of pixel-level ADCs: one with successive approximation register (SAR) ADCs, and the other two with single-slope (SS) ADCs. All of them feature a same pixel size of 35×35 μm2 and a resolution of 3-bit. In this thesis, the prototype is presented for both theoretical analyses and circuit designs. The test results of the prototype are also presented
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Oduwole, Olayinka. "Particle interactions in a magnetophoretic system." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:f01cbb33-4dd4-4057-8891-7097e6493bce.
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The continuous flow separation of magnetic particles from a mixture of particles could improve the performance of magnetic bead based assays but the formation of agglomerates limit the separation efficiency. Bead agglomerates are formed as a result of magnetic binding forces while the hydrodynamic fluid environment strongly influences their movement. The ability to predict the interaction between nearby beads will help to determine a threshold separation distance which will be recommended for use when obtaining measurement within a magnetic bead assay for a specified time interval. The introductory part of this thesis explored the development of a two dimensional numerical model in Matlab which predicts the trajectory pattern as well as magnetic induced velocities between a pair of super-paramagnetic beads suspended in water within a uniform field. The movement of a bead pair interacting due to both magnetic and hydrodynamic forces within a magnetophoretic system was recorded using an optical system; the beads' movements were compared with the simulated trajectories and gave a good agreement. The model was used to predict the shortest agglomeration time for a given separation distance which is of practical benefit to users of bead based assays. The concluding part of this thesis expanded the simulation into a three dimensional model to predict the interactions among three super-paramagnetic beads within a magnetophoretic system. In order to determine the height of the magnetic beads, a Huygens-Fresnel model was implemented in Matlab which was compared with off-focused diffracted images of the beads viewed under an optical system. A good comparison was obtained by comparing the simulated three-dimensional trajectories with experimental data.
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Wu, Bingbing. "Ensuring Respiratory Protection through Respirator Fit Testing and Real-Time Monitoring." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535374058309808.
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Lanoye, Reinhilde. "Assessment of the absorption performance of sound absorbing materials : use of the Trefftz's method and of a new dual particle velocity-pressure sensor." Lyon, INSA, 2007. http://theses.insa-lyon.fr/publication/2007ISAL0031/these.pdf.
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Porous absorbing materials are applied in various fields of sound and noise control. The presented work wants to deliver a numerical simulation tool to predict the acoustical behavior of geometrically complex sound absorbing media under various excitations. To achieve this goal, a deterministic method, which is based on the indirect Trefftz's method and which makes use of solution functions of the governing equations to describe the field variables int he region of interest, is extented to analyze the sound field in and above porous absorbers. The model is experimentally validated and used to analyze the sound field in some real-life configurations. Afterwards, an initial impetus is given towards the further analysis of the absorption performance of various kinds of patchworks under different angles of sound incidence and the study of sound propagation over impedance jumps, with the aid of a model applicable to unbounded problems. Besides the development of the simulation tool, a new dual particle velocity-pressure measurement technique is presentedLes matériaux poreux absorbants constituent une solution avantageuse pour contrôler la qualité du son dans un espace. Le travail présenté propose un outil numérique de simulation en état de prévoir le comportement acoustique des matériaux absorbants géométriquement complexes sous des excitations diverses. Dans ce but, une méthode déterministe est développée pour analyser le champ sonore dans et au-dessus des poreux. La méthode est basée sur la méthode indirecte de Trefftz et se sert de fonctions qui vérifient les équations du problème pour décrire les variables dans la région d'intérêt. Le modèle est expérimentalement validé et employé pour analyser le champ sonore dans quelques configurations réelles. Ensuite, une première impulsion est donnée vers l'analyse du comportement absorbant de matériaux de genres divers à plusieurs angles d'incidence et vers l'étude de la propagation du son proche d'un changement brusque d'impédance, à l'aide d'un modèle applicable aux problèmes infinis. Après le développement de l'outil de simulation, un nouveau capteur mixte de vitesse particulaire et de pression est présenté
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Savic, Vladimir. "Nonparametric Message Passing Methods for Cooperative Localization and Tracking." Doctoral thesis, Technical University of Madrid, Spain, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-81446.
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The objective of this thesis is the development of cooperative localization and tracking algorithms using nonparametric message passing techniques. In contrast to the most well-known techniques, the goal is to estimate the posterior probability density function (PDF) of the position of each sensor. This problem can be solved using Bayesian approach, but it is intractable in general case. Nevertheless, the particle-based approximation (via nonparametric representation), and an appropriate factorization of the joint PDFs (using message passing methods), make Bayesian approach acceptable for inference in sensor networks. The well-known method for this problem, nonparametric belief propagation (NBP), can lead to inaccurate beliefs and possible non-convergence in loopy networks. Therefore, we propose four novel algorithms which alleviate these problems: nonparametric generalized belief propagation (NGBP) based on junction tree (NGBP-JT), NGBP based on pseudo-junction tree (NGBP-PJT), NBP based on spanning trees (NBP-ST), and uniformly-reweighted NBP (URW-NBP). We also extend NBP for cooperative localization in mobile networks. In contrast to the previous methods, we use an optional smoothing, provide a novel communication protocol, and increase the efficiency of the sampling techniques. Moreover, we propose novel algorithms for distributed tracking, in which the goal is to track the passive object which cannot locate itself. In particular, we develop distributed particle filtering (DPF) based on three asynchronous belief consensus (BC) algorithms: standard belief consensus (SBC), broadcast gossip (BG), and belief propagation (BP). Finally, the last part of this thesis includes the experimental analysis of some of the proposed algorithms, in which we found that the results based on real measurements are very similar with the results based on theoretical models.
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Hubble, David Owen. "An experimental investigation of the mechanism of heat transfer augmentation by coherent structures." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/26784.
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The mechanism by which convective heat transfer is augmented by freestream turbulence in the stagnation region was studied experimentally. Previous work has suggested that the primary mechanism for the observed augmentation is the amplification of vorticity into strong vortices which dominate the flow field near the surface. Therefore, two separate experimental investigations were performed to further study this phenomenon. In the first, the spatiotemporal convection from a heated surface was measured during the normal collision of a vortex ring. The convection was observed to increase dramatically in areas where vortices forced outer fluid through the natural convection boundary layer to the surface. Regions where fluid was swept along the surface experienced much smaller increases in convection. These observations led to the development of a mechanistic model which predicted the heat transfer based on the amount of time that fluid remained within the thermal boundary layer prior to reaching the surface. In subsequent testing, the model was able to accurately predict the time-resolved convection based solely on the transient properties of the vortex present. In the second investigation, the model was applied to the vortices which form in a stagnating turbulent flow. Three turbulence conditions were tested which changed the properties of the vortices produced. Again, the model was successful in predicting the time-resolved convection over much of the experimental measurement time.
The work of designing and calibrating the heat flux sensor used is also reported. A new sensor was developed specifically for the convection research performed herein as no existing sensor possessed the required spatiotemporal resolution and underwater capabilities. Utilizing spot-welded foils of thermoelectric alloys resulted in a very robust and sensitive sensing array which was thoroughly analyzed and calibrated. In the final section, the hybrid heat flux (HHF) method is presented which significantly increases the performance of existing heat flux sensors. It is shown (both numerically and experimentally) that by combining the spatial and temporal temperature measurements from a standard sensor, the time response increases by up to a factor of 28. Also, this method causes the sensor to be insensitive to the material to which it is mounted.Ph. D.
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Gifford, Andrew R. "The Physical Mechanism of Heat Transfer Augmentation in Stagnating Flows Subject to Freestream Turbulence and Related Studies." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26097.
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The mechanism of heat transfer augmentation due to freestream turbulence in
classic Hiemenz stagnation flow was studied experimentally for the first time using time-resolved digital particle image velocimetry (TRDPIV) and a new thin film
heat flux sensor called the Heat Flux Array (HFA). Unique measurements of simultaneous, time-resolved velocity and surface heat flux data were obtained along the
stagnation line on a simple, rectangular flat plate model mounted in a water tunnel
facility. Identification and tracking of coherent structures in the stagnation region
lends support to the theory that coherent structures experience stretching and amplification of vorticity by the mean flow strain rate upon approaching the stagnation
surface. The resulting flow field in the near-wall region is comprised primarily of high
strength, counter-rotating vortex pairs with decreased integral length scale relative to
the imposed freestream turbulence. It is hypothesized that the primary mechanism
of heat transfer augmentation is the movement of cooler freestream fluid into the
heated near-wall region by these coherent structures. Furthermore, the level of heat
transfer augmentation is dictated by the integral length scale, circulation strength,
and core-to-surface distance of the coherent structures. To test this hypothesis, these
properties were incorporated into a mechanistic model for predicting the transient,
turbulent heat transfer coefficient. The model was successful in predicting the shape
and magnitude of the measured heat transfer coe±cient over much of the experimental
measurement time.
In a separate yet related set of studies, heat flux sensors and calibration methods
were examined. The High Temperature Heat Flux Sensor (HTHFS) was designed
and developed to become one of the most durable heat flux sensors ever devised for
long duration use in high temperature, extreme environments. Extensive calibrations
in both conduction and convection were performed to validate the performance of the
sensor near room temperature. The measured sensitivities in conduction and convection were both very close to the predicted sensitivity using a thermal resistance model
of the HTHFS. The sensor performance was unaffected by repeated thermal cycling
using kiln and torch firing. Finally, the performance of Schmidt-Boelter heat flux
sensors were examined in both shear and stagnation flow using two custom designed
convection calibration facilities. Calibration results were evaluated using an analytical sensitivity model based on an overall sensor thermal resistance from the sensor
to the heat sink or mounting surface. In the case of convection the model included
a term for surface temperature differences along the boundary layer. In stagnation
flow the apparent sensitivity of the Schmidt-Boelter sensors decreased non-linearly
with increasing heat transfer coefficient. Estimations of the sensor's internal thermal
resistance were obtained by fitting the model to the stagnation calibration data. This
resistance was then used with the model to evaluate the effects of non-uniform surface
temperature on the shear flow sensitivity. A more pronounced non-linear sensitivity
dependence on heat transfer coefficient was observed. In both cases the main result
is that convection sensitivity varies a great deal from standard radiation calibrations.Ph. D.
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Chakraborty, Abhishek. "Development of an on-line aqueous particle sensor to study the performance of inclusions in a 12 tonne, delta shaped full scale water model tundish." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95253.
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Detection of particulate matter thinly dispersed in a fluid medium with the aid of the difference in electrical conductivity between the pure fluid and the particles has been practiced at least since the last 50 to 60 years. The first such instruments were employed to measure cell counts in samples of biological fluid. Following a detailed study of the physics and principles operating within the device, called the Electric Sensing Zone (ESZ) principle, a new device called the Liquid Metal Cleanliness Analyzer (LiMCA) was invented which could measure and count particles of inclusions in molten metal. It provided a fast and fairly accurate tool to make online measurement of the quality of steel during refining and casting operations. On similar lines of development as the LiMCA, a water analogue of the device called, the Aqueous Particle Sensor (APS) was developed for physical modeling experiments of metal refining operations involving water models. The APS can detect and measure simulated particles of inclusions added to the working fluid (water). The present study involves the designing, building and final application of a new and improved APS in water modeling experiments to study inclusion behavior in a tundish operation. The custom built instrument shows superior performance and applicability in experiments involving physical modeling of metal refining operations, compared to its commercial counterparts. In addition to higher accuracy and range of operating parameters, its capability to take real-time experimental data for extended periods of time helps to reduce the total number of experiments required to reach a result, and makes it suitable for analyzing temporal changes occurring in unsteady systems. With the modern impetus on the quality of the final product of metallurgical operations, the new APS can prove to be an indispensable research tool to study and put forward innovative design and parametric changes in industrially practised metallurgical operatLa détection de particules finement dispersées dans un fluide à l'aide de la différence de conductivité entre le liquide pur et les particules est pratiquée depuis environ 50 à 60 ans. Le premier instrument utilisant cette technique fut employé pour mesurer le nombre de cellules dans des échantillons de fluide biologique. Suivant une étude détaillée de la physique et du principe d'opération de l'appareil appelé zone de détection électrique (Electric Sensing Zone -- ESZ), un nouvel appareil, baptisé analyseur liquide de propreté en métal (Liquid Metal Cleanliness Analyzer -- LiMCA), pouvant mesurer le nombre de particules d'inclusion dans les métaux en fusion fut inventé. Cet instrument constituait un outil rapide et précis pour faire des mesures en ligne de la qualité de l'acier au cours du raffinage et de l'opération de coulée. Dans la même lignée de développement que le LiMCA, un outil analogue, spécifique à l'eau, appelé senseur de particules aqueuses (Aqueous Particle Sensor -- APS) fut développé pour la modélisation physique des expériences reliées aux opérations de raffinages des métaux impliquant des modèles aqueux. L'APS peut détecter et mesurer les particules d'inclusions simulées ajoutées au fluide (l'eau). Cette recherche comprend la conception, la réalisation ainsi que l'application finale d'un APS (dans l'eau) nouveau et amélioré appliqué aux expériences de modélisation afin d'étudier le comportement de l'inclusion dans une opération de répartiteur. L'instrument bâti sur mesure démontre une performance supérieure, comparé à ses équivalents commerciaux, applicable dans des expérimentations comprenant de la modélisation physique des opérations de raffinage de métaux. En plus d'une précision accrue et d'un plus grand éventail de paramètres d'opérations, sa capacité de traiter des données expérimentales en temps réel pour de longues périodes rend l'outil en question plus appropriée p
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Murad, Mohammad Omar Faruk. "Acquiring In-Situ High-Resolution Soil Information Using Cost-Effective Technology." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/24626.
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Crop production and ecosystem services are greatly influenced by soil’s physical properties (i.e. soil moisture, organic carbon, particle size distribution, bulk density, etc.). This thesis develops new in-situ and laboratory technologies that can accurately measure soil physical properties rapidly and cost-effectively across the cropping fields.
The first challenge is to build a soil water monitoring system that can monitor crop water use at the plot level. The study used a plastic buggy system for electromagnetic induction (EMI) surveys. The electrical conductivity data recorded from the EMI surveys were used for the depth-specific temporal analyses of soil water use by different genotypes. The system was successfully used to monitor soil water uptake by 36 genotypes of chickpeas at the plot level.
The second challenge is to develop a rapid in-situ soil organic carbon (SOC) measurement technique using a VisNIR penetrometer system with high-resolution in-situ spectra. This method can measure SOC contents accurately from the surface up to the depth of 90 cm.
The thesis also investigates novel laboratory techniques for measuring the particle-size distribution and bulk density. An automated hydrometer method using a ToF distance and a digital temperature sensor was introduced to measure continuous particle-size distribution.
A novel technique based on shear wave velocity using piezoelectric sensors was developed for measuring bulk density and soil stiffness moduli in the laboratory.
These cost-effective and robust measurement systems for measuring 3-dimensional high-resolution soil physical properties can be used in precision agriculture to optimise the resources for maximum crop yields.
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Cannon, Brandon Jeffrey. "Fault Detection for Unmanned Aerial Vehicles with Non-Redundant Sensors." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5308.
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To operate, autonomous systems of necessity employ a variety of sensors to perceive their environment. Many small unmanned aerial vehicles (UAV) are unable to carry redundant sensors due to size, weight, and power (SWaP) constraints. Faults in these sensors can cause undesired behavior, including system instability. Thus, detection of faults in these non-redundant sensors is of paramount importance.The problem of detecting sensor faults in non-redundant sensors on board autonomous aircraft is non-trivial. Factors that make development of a solution difficult include both an inability to perfectly characterize systems and sensors as well as the SWaP constraints inherent with small UAV. An additional challenge is the ability of a fault-detection method to strike a balance between false-alarm rate and detection rate.This thesis explores two model-based methods of fault-detection for non-redundant sensors, a Kalman filter based method and a particle filter based method. The Kalman filter based method employs tests of mean and covariance on the normalized innovation sequence to detect faults, while the particle filter based method uses a function of the average particle weights.The Kalman filter based approach was implemented in real time on board an autonomous rotorcraft using an extended Kalman Filter (EKF). Faults tested included varied levels of bias, drift, and increased noise. Metrics included false-alarm rate, detection rate, and delay to detection. The particle filter based approach was implemented on a simulated system. This was then compared with an implementation of the EKF based approach for the same system. The same fault types and metrics were also used for these tests.The EKF based method of fault-detection performed well onboard the autonomous rotorcraft and should be generalizable to other systems for which an EKF or Kalman filter can be implemented. The theory indicates that the particle filter based algorithm should have performed better, though the simulations showed poor detection characteristics in comparison to the Kalman filter based method. Future work should be performed to explore improvements to the particle filter based method.
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Ahmadi, Kaveh ahmadi. "Dim Object Tracking in Cluttered Image Sequences." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1470147209.
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RAVASENGA, IVAN. "Charged-hadrons production in pp and A-A collisions and characterization of the components for the upgrade of the Inner Tracking System of the ALICE experiment at LHC." Doctoral thesis, Politecnico di Torino, 2019. http://hdl.handle.net/11583/2733955.
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Bhat, Siddharth. "Design and characterization in depleted CMOS technology for particle physics pixel detector." Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0267.
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L’expérience ATLAS commencera à fonctionner avec l’accélérateur LHC à hauteluminosité (HL-LHC) en 2026 pour augmenter la probabilité de nouvelles découvertes. La technologie du détecteur de pixels monolithiques en "depleted" CMOS a été une des options envisagées pour la couche externe du détecteur pixel d’ATLAS mis a niveau et est une technologie à fort potentiel pour les futurs détecteurs a pixels. Dans cette thèse, plusieurs prototypes ont été développés utilisant différentes technologies CMOS appauvries, par exemple, LFoundry (LF) 150 nm, TowerJazz (TJ) à 180 nm et Austriamicrosystems AG (AMS) à 180 nm. Dans un environnement à haute énergie, tel que HL-LHC, les événements uniques (SEU), qui deviennent un sujet de préoccupation pour le bon fonctionnement des circuits. Plusieurs puces de test dans les technologies AMS, TowerJazz et LFoundry avec différentes structures tolérantes au SEU ont été prototypées et testées. Un schéma d’alimentation alternatif appelé schéma d’alimentation série est prévu pour le futur détecteur Inner Tracker (ITk) de l’expérience ATLAS. Pour répondre aux exigences de l’expérience ATLAS concernant l’environnement d’une couche pixélisée dans un environnement de collisionneur à rayonnement élevé, de nouveaux développements avec des capteurs "depleted" CMOS ont été développés dans le régulateur Shunt-LDO et la polarisation de capteur conçus dans la technologie d’imagerie CMOS TowerJazz 0,18 um modifiée. Dans le processus TowerJazz modifié, deux niveaux de tension différents sont utilisés pour l'épuisement du capteur. Polarisation les tensions sont générées à l'aide d'un circuit de pompe à charge négativeThe ATLAS experiment will start operating at the High Luminosity LHC accelerator (HL-LHC) in 2026 to increase the probability of new discoveries. Depleted CMOS monolithic pixel detector technology has been one of the options considered for the outer layer of an upgraded ATLAS pixel detector and is a high potential technology for future pixel detectors. In this thesis, several prototypes have been developed using different depleted CMOS technologies, for instance, LFoundry (LF) 150 nm, TowerJazz (TJ) 180 nm and austriamicrosystems AG (AMS) 180 nm. In a high-energy environment like HL-LHC, Single Event Upsets (SEU), which become of concern for reliable circuit operation. Several test-chips in AMS, TowerJazz and LFoundry technologies with different SEU tolerant structures have been prototyped and tested. The SEU tolerant structures were designed with appropriate electronics simulations using Computer Aided Design (CAD) tools in order to study the sensitivity of injected charge to upset a memory state. An alternative powering scheme named Serial Powering scheme is foreseen for the future Inner Tracker (ITk) detector of the ATLAS experiment. To meet the requirements ofthe ATLAS experiment to the environment of a pixelated layer in a high radiation collider environment, new developments with depleted CMOS sensors have been made in Shunt-LDO regulator and sensor biasing which are designed in modified TowerJazz 180 nm CMOS imaging technology. In the TowerJazz modified process, two different voltage levels are used for the purpose of sensor depletion. The bias voltages are generated by using a negative charge pump circuit
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Kramer, Jeffrey A. "Accurate Localization Given Uncertain Sensors." Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1689.
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The necessity of accurate localization in mobile robotics is obvious - if a robot does not know where it is, it cannot navigate accurately to reach goal locations. Robots learn about their environment via sensors. Small robots require small, efficient, and, if they are to be deployed in large numbers, inexpensive sensors. The sensors used by robots to perceive the world are inherently inaccurate, providing noisy, erroneous data or even no data at all. Combined with estimation error due to imperfect modeling of the robot, there are many obstacles to successfully localizing in the world. Sensor fusion is used to overcome these difficulties - combining the available sensor data in order to derive a more accurate pose estimation for the robot.
In this thesis, we dissect and analyze a wide variety of sensor fusion algorithms, with the goal of using a set of inexpensive sensors in a suite to provide real-time localization for a robot given unknown sensor errors and malfunctions. The sensor fusion algorithms will fuse GPS, INS, compass and control inputs into a more accurate position. The filters discussed include a SPKF-PF (Sigma-Point Kalman Filter - Particle Filter), a MHSPKF (Multi-hypothesis Sigma-Point Kalman Filter), a FSPKF (Fuzzy Sigma-Point Kalman Filter), a DFSPKF (Double Fuzzy Sigma-Point Kalman Filter), an EKF (Extended Kalman Filter), a MHEKF (Multi-hypothesis Extended Kalman Filter), a FEKF (Fuzzy Extended Kalman Filter), and a standard SIS PF (Sequential Importance Sampling Particle Filter).
Our goal in this thesis is to provide a toolbox of algorithms for a researcher, presented in a concise manner. I will also simultaneously provide a solution to a difficult sensor fusion problem - an algorithm that is of low computational complexity (< O(n³)), real-time, accurate (equal in or more accurate than a DGPS (differential GPS) given lower quality sensors), and robust - able to provide a useful localization solution even when sensors are faulty or inaccurate. The goal is to find a locus between power requirements, computational complexity and chip requirements and accuracy/robustness that provides the best of breed for small robots with inaccurate sensors. While other fusion algorithms work well, the Sigma Point Kalman filter solves this problem best, providing accurate localization and fast response, while the Fuzzy EKF is a close second in the shorter sample with less error, and the Sigma-Point Kalman Particle Filter does very well in a longer example with more error. Fuzzy control is also discussed, especially the reason for its applicability and its use in sensor fusion.
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Grall, Simon. "Microcapteurs de particules à base de micropoutres pour le contrôle de la qualité de l'air dans un véhicule automobile." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0038/document.
Full textAbstract:
Les particules fines ont un impact réel sur la qualité de vie et la santé de millions de personnes dans les grandes zones urbaines, notamment en Asie. Pour les détecter et quantifier leur concentration, les capteurs de particules optiques sont les plus couramment étudiés, mais restent relativement chers et volumineux. Les transducteurs MEMS micropoutres sont largement utilisés pour des applications gravimétriques, pour la détection de particules ou de gaz, ce qui requiert des sensibilités massiques (Sm) élevées et des limites de détection (LOD) basses. Pour cela les micropoutres les plus adaptées sont celles ayant des fréquences de résonance (f0) et facteurs de qualité (Q) élevés, avec de faibles bruits de mesure et des masses faibles. Les micropoutres silicium sont couramment utilisées en tant que capteurs gravimétriques et sont de sérieux candidats pour répondre aux caractéristiques souhaitées. Cependant, la sérigraphie a le potentiel pour une fabrication moins chère, plus rapide et aussi à grande échelle. Pour ces micropoutres, l'actionnement et la lecture de f0 sont possibles par effet piézoélectrique. Bien qu'il existe des solutions inorganiques prometteuses sans plomb, les céramiques de titano-zirconate de plomb (PZT) possèdent encore les meilleures propriétés parmi les matériaux piézoélectriques. Des micropoutres fabriquées en technologie hybride couches épaisses sérigraphiées, à actionnement et lecture piézoélectriques intégrés, libérées à l'aide d'une couche sacrificielle polyester et avec co-cuisson de toutes les couches pour leurs libérations sont présentées ici. Différentes géométries ont été testées de 1 mm à 2 mm de large et de 1 mm à 8 mm de long, pour une épaisseur d'environ 100 μm. Une masse volumique ρ PZT = 7200 kg/m³ a été obtenue (≈ 93%ρ PZT massif). Enfin, avec une micropoutre 1×2×0,1 mm³, une sensibilité Sm ≈ 85 Hz/μm et une LOD de 70 ng ont été trouvées, permettant des applications en détection de particulesFine particulate matters (PM) have a real impact on the quality of life and health of millions of people in large urban areas, especially in Asia. In order to detect them and quantify their concentration, optical PM sensors are the most widely studied, but remain relatively expensive and bulky. MEMS microcantilever transducers are widely used for gravimetric applications, for PM or gas detection, which requires high mass sensitivities (Sm) and low limits of detection (LOD). A solution is to focus on microcantilevers with high resonance frequencies (f0) and quality factors (Q), low measurement noise and low masses. Silicon microcantilevers are commonly used as gravimetric sensors and are serious candidates to meet the desired characteristics. However, screen printing has the potential for cheaper, faster and large scale manufacturing. Such microcantilevers can be actuated and f0 read-out using the piezoelectric effect. Although promising lead-free inorganic solutions exist, titanium lead zirconate (PZT) ceramics still have the best properties among piezoelectric materials. Screen-printed microcantilevers manufactured in hybrid thick-film technology, with integrated piezoelectric actuation and read-out, released using a polyester sacrificial layer and with co-firing of all the layers are presented here. Different geometries were tested from 1 mm to 2 mm wide and from 1 mm to 8 mm long, for a thickness of about 100 μm. A density ρ PZT = 7200 kg/m³ (≈ 93%ρ PZT bulk) was obtained. With a 1×2×0.1 mm³ microcantilever, a sensitivity Sm ≈ 85 Hz/μm and a LOD of 70 ng were found, compatible with applications in PM mass detection