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Quelin, Aurélien. « Microstockage électrique pour microrobotique à énergie embarquée ». Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2705.
Texte intégralRésumé :
Une analyse des méthodes de conception des microrobots autonomes en énergie menée durant cette thèse met en évidence le fait que ces méthodes peuvent ne pas être optimales, et que les performances de ces microrobots pourraient être améliorées grâce à un dimensionnement conjoint de leur source d’énergie et de leur système de déplacement. Ces travaux de thèse ont donc cherché à répondre à la problématique suivante : « Y a-t-il un avantage à utiliser des modèles fins pour la conception d’un microrobot, et en particulier pour le dimensionnement conjoint de sa batterie et de son système de déplacement ? ». Pour répondre à cette problématique, nous avons étudié un microrobot autonome en énergie dont il est possible de dimensionner la batterie, de chimie lithium-ion et de format pile bouton, et le système de déplacement, basé sur le principe inertiel impact-drive mis en œuvre autour d’un actionneur électromagnétique. L’étude du dimensionnement conjoint de ces deux composants a été réalisée à l’aide de leurs modèles fins couplés, qui ont préalablement été validés expérimentalement durant la thèse. Nous avons ainsi montré, en utilisant ces modèles couplés, que le dimensionnement optimal du système dans son ensemble ne correspondait pas à la somme des dimensionnements optimaux des composants individuels, mais à un compromis difficile voire impossible à déterminer sans ces modèles couplés, à cause des interactions croisées des effets des paramètres de conception. Le microrobot étudié durant cette thèse a ainsi permis de démontrer l’intérêt de la méthode utilisée, et celle-ci pourrait être utilisée sur d’autres microsystèmes, en fonction de leurs caractéristiquesAn analysis of the design methods of energy autonomous microrobots carried out during this thesis highlights the fact that these methods may not be optimal, and that the performance of these microrobots could be improved through a co-design of their energy source and their motion system. This thesis work therefore addressed the following question : « Is there an advantage to using fine models for the design of a microrobot, and in particular for co-design of its battery and its displacement system? ». To answer this question, we have studied an on-board power supplied microrobot for which it is possible to size the battery, of lithium-ion chemistry and coin cell format, and the displacement system, based on the impact-drive inertial principle implemented around an electromagnetic actuator. The study of the co-design of these two components has been carried out using their coupled fine models, which have been validated experimentally during the thesis. We have shown, using these coupled models, that the optimal sizing of the whole system does not correspond to the sum of the optimal sizings of the individual components, but to a compromise difficult or impossible to determine without these coupled models, because of the cross-interactions of the effects of the design parameters. The microrobot studied during thisthesis has thus demonstrated the interest of the method used, which could be used on other microsystems, depending on their characteristics
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Nguyen, Hugo. « Microsystem Interfaces for Space ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6954.
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Kratz, Henrik. « Integrated Communications and Thermal Management Systems for Microsystem-based Spacecraft : A Multifunctional Microsystem Approach ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Universitetsbiblioteket [distributör], 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6316.
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Rezaei, Masoud. « Multimodal implantable neural interfacing microsystem ». Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/36437.
Texte intégralRésumé :
Afin d’étudier le cerveau humain dans le but d’aider les patients souffrant de maladies neurologiques, on a besoin d’une interface cérébrale entièrement implantable pour permettre l’accès direct aux neurones et enregistrer et analyser l’activité neuronale. Dans cette thèse, des interfaces cerveau-machine implantables (IMC) à très faible puissance basées sur plusieurs circuits et innovations de systèmes ont été étudiées pour être utilisées comme analyseur neuronal. Un tel système est destiné à recueillir l’activité neuronale émise par centaines de neurones tout en les activant à la demande en utilisant des moyens d’actionnement tels que l’électro- et / ou la photo-stimulation. Un tel système doit fournir plusieurs canaux d’enregistrement, tout en consommant très peu d’énergie, et présente une taille extrêmement réduite pour la sécurité et la biocompatibilité. Typiquement, un microsystème d’interfaçage avec le cerveau comprend plusieurs blocs, tels qu’un bloc analogique d’acquisition (AFE), un convertisseur analogique-numérique (ADC), des modules de traitement de signal numérique et un émetteur-récepteur de données sans fil. Un IMC extrait les signaux neuronaux du bruit, les numérise et les transmet à une station de base sans interférer avec le comportement naturel du sujet. Cette thèse se concentre sur les blocs analogiques d’acquisition à très faible consommation à utiliser dans l’IMC. Cette thèse présente des frontaux avec plusieurs stratégies innovantes pour consommer moins d’énergie tout en permettant des données de haute résolution et de haute qualité. Premièrement, nous présentons une nouvelle structure frontale utilisant un schéma de réutilisation du courant. Cette structure est extensible à un très grand nombre de canaux d’enregistrement, grâce à sa petite taille de silicium et à sa faible consommation d’énergie. L’AFE à réutilisation de courant proposée, qui comprend un amplificateur à faible bruit (LNA) et un amplificateur à gain programmable (PGA), utilise une nouvelle topologie de miroir de courant entièrement différentielle utilisant moins de transistors et améliorant plusieurs paramètres de conception, tels que la consommation d’énergie et du bruit, par rapport aux mises en oeuvre de circuit d’amplificateur de réutilisation de courant précédentes. Ensuite, dans la deuxième partie de cette thèse, nous proposons un nouveau convertisseur sigmadelta multicanal qui convertit plusieurs canaux indépendamment en utilisant un seul amplificateur et plusieurs condensateurs de stockage de charge. Par rapport aux techniques conventionnelles, cette méthode applique un nouveau schéma de multiplexage entrelacé, qui ne nécessite aucune phase de réinitialisation pour l’intégrateur lors du passage à un nouveau canal, ce qui améliore sa résolution. Lorsque la taille des puces n’est pas une priorité, d’autres approches peuvent être plus attrayantes, et nous proposons une nouvelle stratégie d’économie d’énergie basée sur un nouveau convertisseur sigma-delta à très basse consommation conçu pour réduire la consommation d’énergie. Ce nouveau convertisseur utilise une architecture basse tension basée sur une topologie prédictive innovante qui minimise la non-linéarité associée à l’alimentation basse tension.Studying brain functionality to help patients suffering from neurological diseases needs fully implantable brain interface to enable access to neural activities as well as read and analyze them. In this thesis, ultra-low power implantable brain-machine-interfaces (BMIs) that are based on several innovations on circuits and systems are studied for use in neural recording applications. Such a system is intended to collect information on neural activity emitted by several hundreds of neurons, while activating them on demand using actuating means like electro- and/or photo-stimulation. Such a system must provide several recording channels, while consuming very low energy, and have an extremely small size for safety and biocompatibility. Typically, a brain interfacing microsystem includes several building blocks, such as an analog front-end (AFE), an analog-to-digital converter (ADC), digital signal processing modules, and a wireless data transceiver. A BMI extracts neural signals from noise, digitizes them, and transmits them to a base station without interfering with the natural behavior of the subject. This thesis focuses on ultra-low power front-ends to be utilized in a BMI, and presents front-ends with several innovative strategies to consume less power, while enabling high-resolution and high-quality of data. First, we present a new front-end structure using a current-reuse scheme. This structure is scalable to huge numbers of recording channels, owing to its small implementation silicon area and its low power consumption. The proposed current-reuse AFE, which includes a low-noise amplifier (LNA) and a programmable gain amplifier (PGA), employs a new fully differential current-mirror topology using fewer transistors. This is an improvement over several design parameters, in terms of power consumption and noise, over previous current-reuse amplifier circuit implementations. In the second part of this thesis, we propose a new multi-channel sigma-delta converter that converts several channels independently using a single op-amp and several charge storage capacitors. Compared to conventional techniques, this method applies a new interleaved multiplexing scheme, which does not need any reset phase for the integrator while it switches to a new channel; this enhances its resolution. When the chip area is not a priority, other approaches can be more attractive, and we propose a new power-efficient strategy based on a new in-channel ultra-low power sigma-delta converter designed to decrease further power consumption. This new converter uses a low-voltage architecture based on an innovative feed-forward topology that minimizes the nonlinearity associated with low-voltage supply.
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Farnsworth, Bradley David. « Wireless Implantable EMG Sensing Microsystem ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1276263665.
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Pauchard, Alexandre. « Silicon sensor microsystem for ultraviolet detection / ». Lausanne, 2000. http://library.epfl.ch/theses/?nr=2152.
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Marselli, Catherine. « Data processing of a navigation microsystem ». Université de Franche-Comté. UFR des sciences et techniques, 1998. http://www.theses.fr/1998BESA2078.
Texte intégralRésumé :
Ce travail de recherche s'inscrit dans un projet académique franco-suisse visant à déterminer les limites des microtechnologies et des microsystèmes à travers l'exemple d'un système de navigation inertiel basé sur des microaccéléromètres et des microcapteurs de vitesse angulaire (gyros). Il comprend quatre volets allant de la conception des composants au développement du système de traitement. La présente thèse réalisée à l'Institut de Microtechnique (Université de Neuchâtel, Suisse) concerne le traitement de l'information du microsystème de navigation. Les microcapteurs actuels sont moins chers mais moins précis que les capteurs mécaniques ou optiques classiques. Dans un système de navigation, le signal de sortie des accéléromètres et des gyroscopes est intégré conduisant à l'accumulation des erreurs dans le temps. Ainsi, en l'absence de correction, la trajectoire mesurée devient rapidement fausse. Le rôle du système de traitement est donc de calculer les paramètres de navigation (position, vitesse et orientation) et de limiter l'erreur de trajectoire suivant deux moyens : réduire les imperfections des capteurs et recaler régulièrement la trajectoire en utilisant un autre moyen de navigation. Ces différents objectifs sont réalisés par des filtres de Kalman. Le filtre de Kalman est un estimateur optimal de l'état d'un système. Il se présente sous la forme d'un ensemble d'équations récurrentes et nécessite une description d'état du système et des mesuresThis research is part of a Swiss French academic project whose goal was the determination of some limits in the design and use of microtechnologies and microsystems, using as a common thread example a navigation system based on microaccelerometers and angular rate microsensors (gyros). The entire project was divided into four parts, including design at the component level as well as at the system level. This PhD report describes the data processing of the navigation microsystem realised at the Electronics and Signal Processing Laboratory of the Institute of Microtechnology, University of Neuchâtel. Current low-cost microsensors are less expensive but less accurate that mechanical or optical sensors. In a navigation system, the accelerometer and gyro outputs are integrated, leading to the accumulation of the errors. Thus, the measured trajectory becomes quickly wrong and a corrective system has to be designed. Hence, the goals of the data processing system is to compute the navigation parameters (position, velocity, orientation) while preventing the trajectory from diverging, following two approaches: reducing the sensor errors,updating regularly the trajectory using an aiding navigation system
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James, Matthew. « Relativistic embedding ». Thesis, University of Bath, 2010. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538128.
Texte intégralRésumé :
The growing fields of spintronics and nanotechnology have created increased interest in developing the means to manipulate the spin of electrons. One such method arises from the combination of the spin-orbit interaction and the broken inversion symmetry that arises at surfaces and interfaces, and has prompted many recent investigations on metallic surfaces. A method by which surface states, in the absence of spin orbit effects, have been successfully investigated is the Green function embedding scheme of Inglesfield. This has been integrated into a self consistent FLAPW density functional framework based on the scalar relativistic K¨olling Harmon equation. Since the spin of the electron is a direct effect of special relativity, calculations involving the spin orbit interaction are best performed using solutions of the Dirac equation. This work describes the extension of Green’s function embedding to include the Dirac equation and how fully relativistic FLAPW surface electronic structure calculations are implemented. The general procedure used in performing a surface calculation in the scalar relativistic case is closely followed. A bulk transfer matrix is defined and used to generate the complex band structure and an embedding potential. This embedding potential is then used to produce a self consistent surface potential, leading to a Green’s function from which surface state dispersions and splittings are calculated. The bulk embedding potential can also be employed in defining channel functions and these provide a natural framework in which to explore transport properties. A relativistic version of a well known expression for the ballistic conductance across a device is derived in this context. Differences between the relativistic and nonrelativistic methods are discussed in detail. To test the validity of the scheme, a fully relativistic calculation of the extensively studied spin orbit split L-gap surface state on Au(111) is performed, which agrees well with experiment and previous calculations. Contributions to the splitting from different angular momentum channels are also provided. The main advantages of the relativistic embedding method are the full inclusion of the spin orbit interaction to all orders, the true semi infinite nature of the technique, allowing the full complex bands of the bulk crystal to be represented and the fact that a only small number of surface layers is needed in comparison to other existing methods.
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Wang, H. (Hongbo). « Silicon X-ray smart sensor micromodule and microsystem ». Doctoral thesis, University of Oulu, 2002. http://urn.fi/urn:isbn:951426746X.
Texte intégralRésumé :
Abstract
Research on X-ray imaging sensors and systems have been carried out for several decades. To make these X-ray scanners smaller with better performance and higher operating speed is an important subject for scientific research and industrial applications.
This thesis covers a whole X-ray line-scan camera system. Special attention is given to the smart sensor micromodule design and processing technology. The smart sensor micromodule is an integrated sensor card that includes both silicon X-ray sensor array and signal-processing integrated circuits, which can perform the functions of both an optical sensor and an analog signal processor. Digital signal processing (DSP) made by application specific integrated circuits (ASICs) is also covered in this thesis.
Processing technology of the photodiode array, design of the integrated circuit, design and packaging of the micromodules are presented in this thesis. The mechanism of photodiode leakage current is studied in detail. Measured results show that the leakage current level of the photodiode array achieves 80 pA/cm2 under zero bias condition, which outperforms the best photodiode reported so far.
The algorithm of the digital signal processing is also studied. The X-ray scanning system can achieve 2 m/s scanning speed with a spatial resolution of 400 mm.
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Saha, Debashis Massachusetts Institute of Technology. « A framework for distributed Web-based microsystem design ». Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/46119.
Texte intégralRésumé :
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 109-111).
The increasing complexity of microsystem design mandates a distributed and collaborative design environment. The high integration levels call for tools and generators that allow exploration of the design space irrespective of the geographical or physical availability of the design tools. The World Wide Web serves as a desirable platform for distributed access to libraries, models and design tools. The rapid growth and acceptance of the World Wide Web has happened over the same time period in which distributed object systems have stabilized and matured. The Web can become an important platform for VLSI CAD, when the distributed object technologies (e.g, CORBA) are combined with the Web technologies (e.g., HTTP, CGI) and Web-aware object oriented languages (e.g., Java). In this thesis, a framework using the Object-Web technologies is presented, which enables distributed Web based CAD. The Object-Web architecture provides an open, interoperable and scalable distributed computing environment for microsystem design, in which Web based design tools can efficiently utilize the capabilities of existing design tools on the Web to build hierarchical Web tools. The framework includes the infrastructure to store and manipulate design objects, protocols for tool communication and WebTop, a Java hierarchical schematic/block editor with interfaces to distributed Web tools and cell libraries.
by Debashis Saha.
M.S.
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Majerus, Steve J. « Wireless, Implantable Microsystem for Chronic Bladder Pressure Monitoring ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1397120012.
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Yang, Chao. « Impedance extraction microsystem for nanostructured electrochemical sensor arrays ». Diss., Connect to online resource - MSU authorized users, 2008.
Trouver le texte intégralRésumé :
Thesis (Ph. D.)--Michigan State University. Dept. of Electrical Engineering, 2008.Title from PDF t.p. (viewed on July 2, 2009) Includes bibliographical references (p. 147-155). Also issued in print.
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Thomas, James David 1969. « Center-embedding and self-embedding in human language processing ». Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/33540.
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Lindeberg, Mikael. « High aspect ratio microsystem fabrication by ion track lithography ». Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2003. http://publications.uu.se/theses/91-554-5515-8/.
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Melin, Jessica. « Novel Microsystem Techniques for Liquid Manipulation and Pressure Sensing ». Doctoral thesis, Stockholm : Department of Signals, Sensors and Systems, Royal Institute of Technology, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-56.
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Suster, Michael August. « High-Performance Wireless Microsystem for MEMS Capacitive Strain Sensors ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1311362499.
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Bernat, Ubiaga Ivan. « Development of a Complete Optical Microsystem for Particle Flow Detection ». Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/133079.
Texte intégralRésumé :
Esta tesis doctoral resume el trabajo realizado en el Departamento de Electrónica de la Facultad de Física, en la Universidad de Barcelona. El objetivo de la misma se centra en el diseño y fabricación de un microsistema óptico basado en la integración híbrida de componentes comerciales y procesos de micromecanizado en silicio, destinado a la detección óptica de micropartículas en chips de microfluídica. Todo ello teniendo como principales metas la miniaturización y la integración de todos los componentes para obtener un sistema robusto, portátil, orientado a aplicaciones “Point of care”.
El sistema de detección óptica de partículas incluye dos elementos comerciales. Por una parte, las fuentes de luz escogidas, láseres VCSEL en formato “die” de la empresa ULM Photonics, y por otra, una matriz de microlentes fabricada por SUSS microOptics. La matriz de microlentes se adapta al pitch que existe entre láseres es de 250 micras, cosa que la hace totalmente compatible en términos de alineación óptica.
Para determinar las posiciones óptimas de estos componentes, se realiza el estudio de dos escenarios mediante el uso de un simulador de trazado de rayos (ZEMAX Radiance ®): el primero, basado en la obtención de haces de luz colimados; el segundo, basado en la obtención de haces de luz focalizados.
Los componentes comerciales se ensamblan en una estructura robusta, formada por dos piezas de silicio (base y separador óptico), y con alienación pasiva de las microlentes. Las piezas de silicio se fabrican en obleas siguiendo procesos de Sala Blanca.
Mediante técnicas de soft lithography se diseñan y fabrican diversos chips para el bloque de microfluídica: canales con focalización pasiva del flujo y canales con sistemas de focalización activa. Dichos chips contienen los canales de microfluídica por donde circularán las partículas que se pretende detectar, en suspensión líquida.
El sistema de detección óptica de partículas requiere de un sensor óptico encargado de detectar las variaciones en los niveles de intensidad luminosa causadas por la circulación de partículas. En esta tesis se plantea un sensor de imagen basado en tecnología CMOS, con un diseño full-custom. El sensor contiene una estructura en doble array lineal con 256 pixels.
Para validar la funcionalidad del sistema fabricado, se realizó una batería de pruebas. Se prepararon diversas suspensiones acuosas en agua desionizada e isopropanol con partículas de diferentes tamaños (diámetros), materiales y fabricantes en un rango de 10 a 90micras de diámetro. Los resultados fueron satisfactorios en todos los casos.This thesis summarizes the work developed in the Department of Electronics, Faculty of Physics, at the University of Barcelona. This work is focused on the design and fabrication of an optical microsystem based on hybrid integration of commercial components and silicon micromachining processes, in order to the optical detection of microparticles in microfluidic chips. Main goals are the miniaturization and integration of all components to obtain a robust system, portable, and oriented to "Point of care" applications. The optical detection system includes two commercial components. First, the chosen light sources, VCSEL lasers in "die " format from ULM Photonics, and second, an array of microlenses manufactured by SUSS microoptics. The microlens array fits the existing pitch between lasers (250 microns), therefore it is fully compatible in terms of optical alignment. To determine the optimal positions of these components, two scenarios are analyzed by using a ray tracing simulator (ZEMAX Radiance ®): the first, based on collimated light beams, the second based on obtaining focused light beams. The commercial components are assembled in a robust structure, consisting of two pieces of silicon (base and optical spacer), and passive alignment of the microlenses. The pieces of silicon are fabricated in wafers at the clean room of the IBM-CNM, according to the defined processes. Using soft lithography techniques, various chips for the microfluidic block are designed and fabricated: passive focusing channels and channels with hydrodynamic focusing. These chips contain microfluidic channels where particles to be detected will flow in liquid suspension. The optical detection system requires an optical sensor to detect the variations in the levels of light intensity caused by the particles circulation. In this thesis, an image sensor based on CMOS technology and a full-custom design is presented. The sensor includes a double linear array structure with 256 pixels and other electronics. To validate the functionality of the proposed system, we performed a battery of tests. Several aqueous suspensions were prepared in deionized water and isopropanol with particles of different sizes (diameters) materials and manufacturers in the range of 10 to 90micras diameter. The results were satisfactory in all cases.
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Tan, Su-Lim. « Smart chemical sensing microsystem : towards a nose-on-a-chip ». Thesis, University of Warwick, 2005. http://wrap.warwick.ac.uk/61912/.
Texte intégralRésumé :
The electronic nose is a rudimentary replica of the human olfactory system. However there has been considerable commercial interest in the use of electronic nose systems in application areas such as environmental, medical, security and food industry. In many ways the existing electronic nose systems are considerable inferior when compared to their biological counterparts, lacking in terms of discrimination capability, processing time and environmental adaptation. Here, the aim is to extract biological principles from the mammalian olfactory systems to create a new architecture in order to aid the implementation of a nose-on-a-chip system. The primary feature identified in this study was the nasal chromatography phenomena which may provide significant improvement by producing discriminatory spatio-temporal signals for electronic nose systems. In this project, two different but complimentary groups of systems have been designed and fabricated to investigate the feasibility of generating spatio-temporal signals. The first group of systems include the fast-nose (channel 10 cm x 500 μm2), proto-nose I (channel 1.2 m x 500 μm2) and II (channel 2.4 m x 500 μm2) systems that were build using discrete components. The fast-nose system was used to characterise the discrete sensors prior to use. The proto-nose systems, in many ways, resembles gas chromatography systems. Each proto-nose system consists of two microchannels (with and without coating) and 40 polymer-composite sensors of 10 different materials placed along it. The second group of systems include the hybrid-nose and the aVLSI-nose microsensor arrays assembled with microchannel packages of various lengths (5 cm, 32 cm, 7lcm, 240 cm) to form nose-on-a-chip systems. The hybrid-nose sensor array consists of 80 microsensors built on a 10 mm x 10 mm silicon substrate while the aVLSI-nose sensor array consists of 70 microsensors built on a 10 mm x 5 mm silicon substrate using standard CMOS process with smart integrated circuitries. The microchannel packages were fabricated using the Perfactory microstereolithography system. The most advanced microchannel package contains a 2.4 m x 500 J.lm2 microchannel with an external size of only 36 mm x 27 mm x 7 mm. The nose-on-a-chip system achieved miniaturisation and eliminates the need for any external processing circuitries while achieving the same capability of producing spatio-temporal signals. Using a custom-designed vapour test station and data acquisition electronics, these systems were evaluated with simple analytes and complex odours. The experimental results were in-line with the simulation results. On the coated proto-nose II system, a 25 s temporal delay was observed on the toluene vapour pulse compared to ethanol vapour pulse; this is significant compared to the uncoated system where no delay difference was obtained. Further testing with 8 analyte mixtures substantiated that spatio-temporal signals can be extracted from both the coated proto-nose and nose-on-a-chip (hybrid-nose sensor array with 2.4 m long microchannel) systems. This clearly demonstrates that these systems were capable of imitating certain characteristics of the biological olfactory system. Using only the temporal data, classification was performed with principal components analysis. The results reinforced that these additional temporal signals were useful to improve discrimination analysis which is not possible with any existing sensor-based electronic nose system. In addition, fast responding polymer-composite sensors were achieved exhibiting response times of less than 100 ms. Other biological characteristics relating to stereolfaction (two nostrils sniffing at different rates), sniffing rate (flow velocity) and duration (pulse width) were also investigated. The results converge with the biological observations that stereolfaction and sniffing at higher rate and duration improve discrimination. Last but not least, the characterisation of the smart circuitries on the aVLSI-nose show that it is possible to achieve better performance through the use of smart processing circuitries incorporating a novel DC-offset cancellation technique to amplify small sensor response with large baseline voltage. The results and theories presented in this study should provide useful contribution for designing a higher-performance electronic nose incorporating biological principles.
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Azin, Meysam. « A Battery-Powered Multichannel Microsystem for Activity-Dependent Intracortical Microstimulation ». Case Western Reserve University School of Graduate Studies / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=case1298389278.
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Merrick, Ian. « Embedding at electrode surfaces ». Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55969/.
Texte intégralRésumé :
Electronic structure calculations are performed on metal surfaces using an embedding method. Firstly, Cu and Ni surfaces with adsorbates are studied. The O/Cu(00T) reconstruction is investigated, and it is found that atomic displacements increase bonding symmetry and is most likely the cause of reconstruction. The interaction between a single graphitic layer and the Ni(III) substrate is also studied, and it is found that interacting states are formed at Ni band gaps. The remainder of the thesis deals with steps on metal surfaces. First, the jellium model is used to calculate the work function dependence on step density. In the low step density limit, the work function varies linearly with step density. Further calculations are performed on realistic Pd and Pt surfaces. When electric fields are applied, the screening charge of stepped surfaces is mostly located at the step edge. This is explained by the increased fields associated with the edge. Field emission from Pd and Pt surfaces is also studied. It is found that Pd is a better emitter than Pt, owing to work function effects. Transmission is dependent on the surface parallel wavevector and decreases with increasing wavevector. The reduced work function also plays a role at stepped surfaces, although the major influence stems from the reduced local work function at the step site. The low effective potential at the step provides a locally reduced barrier to electron removal. In addition, an increase in transmission is seen from non-zero wavevectors for stepped surfaces. The result is that stepped Pd and Pt surfaces, with a step density of one step in every three (001) unit cells, show field emission increased by a factor of four compared with the flat (001) surfaces.
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Persson, Milton. « The Whitney embedding theorem ». Thesis, Umeå universitet, Institutionen för matematik och matematisk statistik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-91352.
Texte intégralRésumé :
A fundamental theorem in differential geometry is proven in this essay. It is the embedding theorem due to Hassler Whitney, which shows that the ever so general and useful topological spaces called manifolds, can all be regarded as subspaces of some Euclidean space. The version of the proof given in this essay is very similar to the original from 1944. Modern definitions are used, however, and many illustrations have been made, wherever it helps the understanding.
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Wheeldon, Elizabeth. « Embedding nanofibres in fabrics ». Thesis, University of York, 2018. http://etheses.whiterose.ac.uk/20232/.
Texte intégralRésumé :
Low molecular weight gelators (LMWGs) form a network through non-covalent interactions to immobilise solvent and form a gel. Upon drying, the solvent evaporates, leaving behind nanofibres. The main aim of this project was to enhance the filtration properties of a non-woven fabric while minimising impact on the intrinsic air permeability and water vapour permeability. A range of supramolecular nanofibres were investigated, based on 1,3:2,4-dibenzylidene-D-sorbitol (DBS) and compared to N,N’,N”-tris(2-ethylhexyl)-1,3,5-benzenetricarboxamide (BTA) as a benchmark, which has been previously used in the literature in a similar way. Various self-assembled nanostructures have been successfully incorporated into a non-woven fabric including DBS, BTA, DBS-CONHNH2, DBS-SCH3, DBS-OCH3 and small amounts of additives including a DBS dimer, poly(ethylene glycol) and poly(vinyl acetate). The nanoscale morphology was similar for all DBS derivatives. However, BTA gave rise to much larger nanofibres. Non-woven fabrics prepared with DBS, BTA, DBS-SCH3 and a mixture of both DBS and BTA were scaled up and tested for air permeability (AP) and water vapour permeability (WVP). It was found that in most cases, there was a negative correlation between AP and concentration of gelator used to prepare the fabric, although WVP did not appear affected by the presence of nanofibres. The exception was DBS-SCH3 which, at the loadings tested, did not appear to impact on AP. Fabrics prepared with a mixture of DBS and BTA produced a selfsorted network, with three different length-scaled fibres (DBS, BTA and fabric). All the modified fabrics gave AP and WVP results in the range of current protective textiles. Fabrics prepared with DBS and BTA performed very similarly under filtration testing, both in forced conditions and in a more realistic setting. There was some evidence that the smaller DBS nanofibres were physically more robust. Substitution of BTA is thereby possible with a cheap, commercial product, DBS. Under realistic conditions, both gelators enhanced the filtration of a non-woven fabric against aerosols.
23
Carlstrom, Brian D. (Brian David) 1973. « Embedding scheme in Java ». Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/16764.
Texte intégralRésumé :
Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2001.Includes bibliographical references (p. 171-176).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Extension languages are an important part of modern applications development. Java as a platform does not provide a standard extension language. Scheme is one possible choice as an extension language for Java. There are a variety of techniques for implementing Scheme in Java varying from interpreting s-expressions to compiling into Java byte-codes. The historical evolution of one implementation is discussed over the course of several years. The design of the Java-to-Scheme and Scheme-to-Java interfaces is reviewed. The advantages and disadvantages of Java and Scheme are compared.
by Brian D. Carlstrom.
M.Eng.
24
Demirci, Kemal Safak. « Chemical microsystem based on integration of resonant microsensor and CMOS ASIC ». Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/41182.
Texte intégralRésumé :
The main topic of this thesis is the development of a chemical microsystem based on integration of a silicon-based resonant microsensor and a CMOS ASIC for portable sensing applications. Cantilever and disk-shape microresonators have been used as mass-sensitive sensors. Based on the characteristics of the microresonators, CMOS integrated interface and control electronics have been implemented. The CMOS ASIC utilizes the self-oscillation method, which incorporates the microresonator in an amplifying feedback loop as the frequency determining element. In this manner, the ASIC includes a main feedback loop to sustain oscillation at or close to the fundamental resonance frequency of the microresonator. For stable oscillation, an automatic gain control loop regulates the oscillation amplitude by controlling the gain of the main feedback loop. In addition, an automatic phase control loop has been included to adjust the phase of the main feedback loop to ensure an operating point as close as possible to the resonance frequency, resulting in improved frequency stability. The CMOS chip has been interfaced to cantilever and disk-shape microresonators and short-term frequency stabilities as low as 3.4×10-8 in air have been obtained with a 1 sec gate time.
The performance of the implemented microsystem as a chemical sensor has been evaluated experimentally with microresonators coated with chemically sensitive polymer films. With a gas-phase chemical measurement setup constructed in this work, chemical measurements have been performed and different concentrations of VOCs, such as benzene, toluene and m-xylene have been detected with limits of detection of 5.3 ppm, 1.2 ppm and 0.35 ppm, respectively.
To improve the long-term stability in monitoring applications with slowly changing analyte signatures, a method to compensate for frequency drift caused by environmental disturbances has been implemented on the CMOS chip. This method uses a controlled stiffness modulation generated by a frequency drift compensation circuit to track the changes in the resonator's Q-factor in response to variations in the environmental conditions. The measured Q-factor is then used to compensate for the frequency drift using an initial calibration step. The feasibility of the proposed method has been verified experimentally by compensating for temperature-induced frequency drift during gas-phase chemical measurements.
25
Rowland, Emily. « Influences of the Neonatal Intensive Care Unit Microsystem on Mothers' Experiences ». Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32418.
Texte intégralRésumé :
The goal of this project was to explore mothers’ experiences of caring for infants in the Neonatal Intensive Care Unit (NICU) using a microsystem perspective. This perspective focuses on the structure, processes and people and in so doing allows for a critical exploration of how these elements work together to influence mothers in the NICU. The research framework involved an institutional ethnography to explore care delivery, relationships, and discourses in the NICU. Data was collected using nonparticipant-observations, interviews, and collection of discourse artifacts. There is clear evidence that caring for an infant in the NICU can result in significant increases in maternal stress and associated outcomes. Results from triangulation of the data indicated that being separated from the infant and learning to mother in the unit were particularly salient experiences retold by the mothers. These experiences were affected – either positively or negatively – by different elements of the microsystem including consistency in communications, increased opportunities for mothers’ inclusion in decision-making and infant care and lastly, access to more support resources. Implementing improvements to the microsystem could better empower mothers adjusting to parenthood within the NICU context.
26
Jiang, Xin. « Diode laser processing of PMMA and LCP materials for microsystem packaging ». Thesis, Heriot-Watt University, 2015. http://hdl.handle.net/10399/3008.
Texte intégralRésumé :
The thesis describes the development of laser-assisted bonding methods for assembly of microfluidic devices and MEMS packaging. A laser microwelding technique for assembly of transparent polymer substrates for fabrication of microfluidic devices was studied. The transparent PMMA substrates were bonded together using a high power diode laser system with a broad top-hat beam profile and an intermediate titanium thin film consisting of 0.7 mm diameter spots. A tensile strength of 6 MPa was achieved for this novel method which is comparable to that of the previous work in laser welding of polymers. It has been demonstrated that the method is capable of leak free encapsulation of a microfluidic channel. Furthermore, a novel laser-based method using an LCP film for packaging of MEMS, sensors and other microelectronic devices has been investigated. The results show that it is possible to use a laser based method with an LCP polymer for high quality substrate bonding applications. Glass-glass based cavities allow optical transmission and have potential applications for optical sensors and other photonic devices. For glass-glass bonding, it was shown that thin film titanium material can be used as an effective optical absorber in the laser based LCP bonding technique. Laser bonding of glass and silicon using an LCP film has also been achieved but in this case the silicon substrate acted as the absorber to capture the laser power. Laser bonding of a silicon cap to a molded LCP package has also been demonstrated successfully. The results of temperature monitoring using embedded sensors show that the temperature at the base of the LCP package (~130C) is substantially lower than the bonding temperature (> 280C). The results of shear and leak test show good reliability and hermeticity of the laser bonded microcavities. Both two-dimensional and three-dimensional models of heat transfer are developed and studied using the COMSOL Multiphysics software tool to understand the localised laser heating effects. The results are in good agreement with those of the practical work.
27
LaFave, Lea R. Ayers. « Nursing Practice as Knowledge Work Within a Clinical Microsystem : A Dissertation ». eScholarship@UMMS, 2008. https://escholarship.umassmed.edu/gsn_diss/9.
Texte intégralRésumé :
Nurses have a key role in keeping patients safe from medical errors because they work at the point of care where most errors occur. Nursing work at the intersection of patients and health care systems requires high levels of cognitive activity to anticipate potential problems and effectively respond to rapidly evolving and potentially harmful situations. The literature describes nursing work at the intersection of patient and health care system as well as barriers to providing safe patient care. However, little is known about the systems knowledge nurses use to negotiate the health care system on their patients’ behalf, or how this systems information is exchanged between nurses.
Using the clinical microsystem as the conceptual framework, this qualitative descriptive investigation identified and described: 1) the components of systems knowledge needed by nurses, 2) how systems information is exchanged between nurses, and 3) systems information exchanged between staff nurses and travel nurses. Data were collected from a stratified maximum variation sample of 18 nurse leaders, staff nurses, and travel nurses working within a high-functioning neonatal intensive care nursery within a large academic medical center in New England. Data collection methods included participant observation, document review, individual interviews, and a focus group session. Data were analyzed through constant comparison for emerging themes and patterns. Findings were compared for commonalities and differences within and across groups.
Three components of systems knowledge emerged: structural, operational, and relational. Systems information exchange occurred through direct and indirect means. Direct means included formal and informal mechanisms. The formal mechanism of orientation was identified by each participant. Informal mechanisms such as peer teaching, problem solving, and modeling behaviors were identified by participants from each of the three nurse groups. Travel nurses’ descriptions of the common themes focused on individual efficacy. Staff nurses focused on fostering smooth unit functioning. Nurse leaders described common themes from a perspective of unit development. Four overarching domains of systems information were exchanged between staff nurses and travel nurses: practice patterns; staffing patterns and roles; tips, tricks, tidbits, and techniques; and environmental elements. Communication emerged as a common theme across nurse groups and domains of systems information exchanged. These findings have implications for nursing orientation and staff development, continuous improvement at the local level, and curriculum development.
28
Muir, Keith Ross. « Mixed-mode microsystems for biological cell actuation and analysis ». Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/28879.
Texte intégralRésumé :
Personalised medicine is widely considered to be the future of global healthcare, where diagnosis, treatment, and potentially even drug development, will become specific to, and optimised for, each individual patient. Traditional population based cell studies suppress the influence of outlier cells that are frequently those of most clinical relevance. Hence single-cell analysis is becoming increasingly important in understanding disease, aiding diagnosis and selecting tailored treatment; but remains the preserve of biomedical laboratories far from the patient. Current instruments depend upon cell-labelling to identify the cell type(s) of interest, which require that these be chosen a-priori and may not be those most clinically relevant. Furthermore, cell-labelling is fundamentally subjective, requiring highly-skilled operators to decide upon the validity of each and every test. Therefore, new test methods need to be developed to enable the widespread adoption of single-cell analysis. The passive electrical properties of biological cells are known to be indicative of the specific cell type, but no technology has demonstrated their comprehensive measurement within a mass-manufacturable device. This work aims to show that biologically meaningful information can be obtained in the form of identifiable “cell signatures” through broadband frequency measurements spanning 100 kHz to 100 MHz that exploit the properties of differential electric fields. This hypothesis is tested through the design, implementation and experimental testing of a dedicated microsystem that integrates two novel designs of electrical sensor within a standard, mass-manufacturable Complementary Metal-Oxide Semiconductor microelectronics technology. One sensor measures the absolute electrical environment above a single sense electrode. The other measures the difference in electrical environment between a pair of electrodes, with view to provide information regarding the suspended cell only, through rejecting the common signal due to its suspending medium. Both sensors are shown capable of detecting individual biological cells in physiological solution, and the differential sensor capable of identifying individually-fixed red blood cells, cervical cancer HeLa cells, and three diameters of homogeneous polystyrene micro-beads of comparable size, all while suspended in physiological saline. These results confirm the hypothesis that differential electric fields provide greater distinction of suspended cells from their environment than existing electrical methods. This finding shows that electrode polarisation arising from proximity to liquids, and particularly physiological media, can be overcome through fully-differential electrical cell sensing. However, misalignment between cells and sensor electrodes limits the sensitivity achieved with the microsystem. Methods to overcome such alignment issues should be investigated in future work, along with higher frequency measurements beyond those presented here.
29
Yalim, Keles Hacer. « Part Embedding For Shape Grammars ». Phd thesis, METU, 2010. http://etd.lib.metu.edu.tr/upload/12612231/index.pdf.
Texte intégralRésumé :
Computational modeling of part relations of shapes is a challenging problem that has been addressed by many researchers since sixties. The most important source of the difficulty is the continuous nature of shapes, which makes the expression of shape very difficult in terms of discrete parts. When discrete parts are combined, they fuse and yield new parts, i.e. parts emerge. There is a number of methods that support emergent part detection. However all of these methods are based on strong assumptions in terms of what constitute a part. There is a need for a generic solution that treats a shape independently of any restriction resulting from
analytical, geometrical, or logical abstractions. To this end, we have developed two novel strategies, which can be used both separately and jointly. Both strategies are relatable to the algebraic formalization of shape grammars (by Stiny). In the course of this thesis work, we have introduced a novel data structure called Over-Complete Graph to address the problem of part embedding in the existence of discrete registration marksand we have developed a novel and robust method for the automatic selection of registration marks. Both developments are certainly useful for other visual problems. On the application side, we have tested our techniques on puzzling Seljuk patterns (from Kayseri) to demonstrate how the developed techniques give way to computational creativity. Apart from the techniques we have developed, the most important contribution of our work is that shapes are treated as perceived wholes rather than composed, as compellingly demonstrated by Seljuk pattern experiments.
30
Leuthäuser, Max. « A Pure Embedding of Roles ». Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-227624.
Texte intégralRésumé :
Present-day software systems have to fulfill an increasing number of requirements, which makes them more and more complex. Many systems need to anticipate changing contexts or need to adapt to changing business rules or requirements. The challenge of 21th-century software development will be to cope with these aspects. We believe that the role concept offers a simple way to adapt an object-oriented program to its changing context. In a role-based application, an object plays multiple roles during its lifetime. If the contexts are represented as first-class entities, they provide dynamic views to the object-oriented program, and if a context changes, the dynamic views can be switched easily, and the software system adapts automatically. However, the concepts of roles and dynamic contexts have been discussed for a long time in many areas of computer science. So far, their employment in an existing object-oriented language requires a specific runtime environment. Also, classical object-oriented languages and their runtime systems are not able to cope with essential role-specific features, such as true delegation or dynamic binding of roles. In addition to that, contexts and views seem to be important in software development. The traditional code-oriented approach to software engineering becomes less and less satisfactory. The support for multiple views of a software system scales much better to the needs of todays systems. However, it relies on programming languages to provide roles for the construction of views.
As a solution, this thesis presents an implementation pattern for role-playing objects that does not require a specific runtime system, the SCala ROles Language (SCROLL). Via this library approach, roles are embedded in a statically typed base language as dynamically evolving objects. The approach is pure in the sense that there is no need for an additional compiler or tooling. The implementation pattern is demonstrated on the basis of the Scala language. As technical support from Scala, the pattern requires dynamic mixins, compiler-translated function calls, and implicit conversions. The details how roles are implemented are hidden in a Scala library and therefore transparent to SCROLL programmers. The SCROLL library supports roles embedded in structured contexts. Additionally, a four-dimensional, context-aware dispatch at runtime is presented. It overcomes the subtle ambiguities introduced with the rich semantics of role-playing objects. SCROLL is written in Scala, which blends a modern object-oriented with a functional programming language. The size of the library is below 1400 lines of code so that it can be considered to have minimalistic design and to be easy to maintain. Our approach solves several practical problems arising in the area of dynamical extensibility and adaptation.
31
Wang, Joy (Joy Yuk-Hwa) 1975. « Re-embedding the global soul ». Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/70734.
Texte intégralRésumé :
Thesis (M. Arch.)--Massachusetts Institute of Technology, Dept. of Architecture, 2001.Includes bibliographical references (p. 40-41).
This thesis proposes to "re-embed" the "global nomad" into the context of an increasingly globalized world at the room scale. I define re-embedding as the "plugging in" of social relationships to local contexts and their recombination across time/space distances in order to establish a sense of continuity and order in events including those not directly within the perceptual environment of the individual. The term global nomads refer to a population of people who travel frequently and globally due to the nature of their jobs. Their transitory lifestyle restricts them to live principally in hotels or other temporary accommodations. The options available to global nomads are limited and do not adequately provide for the sense of place. The research focuses on the lifestyle of global nomads from fashion, technology, to living environment i.e. furniture. It interprets fashion and technology as layers and wires that both filter and protect the global nomads like a cocoon. It interprets the blase attitude towards thehomogeneouss living environment in the urban, metropolitan context as the culprit for the need to liberate. The thesis aims to expand the dimension of the 'cocoon' through the design of a wall of technology (transient) and the room as an open landscape (permanent) where the making-of place can begin to happen. The room then becomes an object that can be strategically 'plugged in' to existing buildings at nodes of an intense, urban context locally.
Joy Wang.
M.Arch.
32
Leuthäuser, Max. « Pure Embedding of Evolving Objects ». International Academy, Research, and Industry Association, 2017. https://tud.qucosa.de/id/qucosa%3A70692.
Texte intégralRésumé :
Scripting languages are extraordinarily popular due to their very flexible object model. Dynamic extensions (i.e., adding, removing and manipulating behavior and state) allow for the evolution and adaption of objects to context changes at runtime. Introducing this flexibility into a statically typed, object-oriented language would improve programmability and separation of concerns beyond the level of what one could usually gain with inheritance, mixins, traits or manually adapted designpatterns. They often lead to object-schizophrenia or the need for hand-crafted, additional management code. Although there were already attempts bringing flexible objects into statically typed languages with the benefits of an explicitly crafted core calculus or type system, they need their own compiler and tooling which limits the usability, e.g., when dealing with existing legacy code. This work presents an embedding of dynamically evolving objects via a lightweight library approach, which is pure in the sense, that there is no need for a specific compiler or tooling. It is written in Scala, which is both a modern object-oriented and functional programming language. Our approach is promising to solve practical problems arising in the area of dynamical extensibility and adaption like role-based programming.
33
Björk, Kevin. « Embedding inflation in string theory ». Thesis, Uppsala universitet, Teoretisk fysik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-392100.
Texte intégralRésumé :
We introduce slow-roll inflation in string theory on both a conceptual level and a detailed one. In order to do this we first briefly review important concepts of inflation and string theory. We then reconstruct models of string inflation in the so-called Racetrack scenario for two different cases where the difference being the number of Kähler moduli used as inflaton. Furthermore, we briefly relate our results to the more recent discussion on whether AdS/dS solutions actually exist in string theory. In this instance our results seem to indicate that uplifting is a crucial component to obtain AdS/dS solutions.
34
Estrella, Balderrama Alejandro. « Simultaneous Embedding and Level Planarity ». Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195738.
Texte intégralRésumé :
Graphs are a common model for representing information consisting of a set of objects or entities and a set of connections or relations between them. Graph Drawing is concerned with the automatic visualization of graphs in order to make the information useful. That is, a good drawing should be helpful in the application domain where it is used by capturing the relationships in the underlying data. We consider two important problems in automated graph drawing: simultaneous embedding and level planarity. Simultaneous embedding is the problem of drawing multiple graphs while maintaining the readability of each graph independently and preserving the mental map when going from one graph to another. In this case, each graph has the same vertex set (same entities) but different edge sets (different relationships). Level planarity arises in the layout of graphs that contain hierarchical relationships. When drawing graphs in the plane, this translates to a restricted form of planarity where the vertical order of the entities is pre-determined. We consider the computational complexity of the simultaneous embedding problem. In particular, we show that in its generality the simultaneous embedding problem is NP-hard if the edges are drawn as straight-lines. We present algorithms for drawing graphs on predetermined levels, which allow the simultaneous embedding of restricted types of graphs, such as outerplanar graphs, trees and paths. Finally, our practical contribution is a tool that implements known and novel algorithms related to simultaneous embedding and level planarity and can be used both as a visualization software and as an aid to study theoretical problems.
35
Wu, Y. « Embedding approaches for relational data ». Thesis, University of Liverpool, 2018. http://livrepository.liverpool.ac.uk/3016866/.
Texte intégralRésumé :
Embedding methods for searching latent representations of the data are very important tools for unsupervised and supervised machine learning as well as information visualisation. Over the years, such methods have continually progressed towards the ability to capture and analyse the structure and latent characteristics of larger and more complex data. In this thesis, we examine the problem of developing efficient and reliable embedding methods for revealing, understanding, and exploiting the different aspects of the relational data. We split our work into three pieces, where each deals with a different relational data structure. In the first part, we are handling with the weighted bipartite relational structure. Based on the relational measurements between two groups of heterogeneous objects, our goal is to generate low dimensional representations of these two different types of objects in a unified common space. We propose a novel method that models the embedding of each object type symmetrically to the other type, subject to flexible scale constraints and weighting parameters. The embedding generation relies on an efficient optimisation despatched using matrix decomposition. And we have also proposed a simple way of measuring the conformity between the original object relations and the ones re-estimated from the embeddings, in order to achieve model selection by identifying the optimal model parameters with a simple search procedure. We show that our proposed method achieves consistently better or on-par results on multiple synthetic datasets and real world ones from the text mining domain when compared with existing embedding generation approaches. In the second part of this thesis, we focus on the multi-relational data, where objects are interlinked by various relation types. Embedding approaches are very popular in this field, they typically encode objects and relation types with hidden representations and use the operations between them to compute the positive scalars corresponding to the linkages' likelihood score. In this work, we aim at further improving the existing embedding techniques by taking into account the multiple facets of the different patterns and behaviours of each relation type. To the best of our knowledge, this is the first latent representation model which considers relational representations to be dependent on the objects they relate in this field. The multi-modality of the relation type over different objects is effectively formulated as a projection matrix over the space spanned by the object vectors. Two large benchmark knowledge bases are used to evaluate the performance with respect to the link prediction task. And a new test data partition scheme is proposed to offer a better understanding of the behaviour of a link prediction model. In the last part of this thesis, a much more complex relational structure is considered. In particular, we aim at developing novel embedding methods for jointly modelling the linkage structure and objects' attributes. Traditionally, link prediction task is carried out on either the linkage structure or the objects' attributes, which does not aware of their semantic connections and is insufficient for handling the complex link prediction task. Thus, our goal in this work is to build a reliable model that can fuse both sources of information to improve the link prediction problem. The key idea of our approach is to encode both the linkage validities and the nodes neighbourhood information into embedding-based conditional probabilities. Another important aspect of our proposed algorithm is that we utilise a margin-based contrastive training process for encoding the linkage structure, which relies on a more appropriate assumption and dramatically reduces the number of training links. In the experiments, our proposed method indeed improves the link prediction performance on three citation/hyperlink datasets, when compared with those methods relying on only the nodes' attributes or the linkage structure, and it also achieves much better performances compared with the state-of-arts.
36
Sudireddy, Samara Simha Reddy. « Accumulator Based Test Set Embedding ». OpenSIUC, 2009. https://opensiuc.lib.siu.edu/theses/18.
Texte intégralRésumé :
In this paper a test set embedding based on accumulator driven by an odd additive constant is presented. The problem is formulated around finding the location of the test pattern in the sequence generated by the accumulator, given a odd constant C and test set T, in terms of linear Diophantine equation of two variables. We show that the search space for finding the best constant corresponding to the shortest length, is greatly reduced. Experimental results show a significant improvement in run time with practically acceptable test length.
37
Nguyenhuu, Rick Hung. « Torus embedding and its applications ». CSUSB ScholarWorks, 1998. https://scholarworks.lib.csusb.edu/etd-project/1572.
Texte intégral
38
Ruryk, Andriy. « Development of microsystem technology suitable for bacterial identification and gene expression monitoring ». [S.l.] : [s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=974502286.
Texte intégral
39
Koev, Stephan Todorov. « Design, fabrication, and testing of a microsystem for monitoring bacterial quorum sensing ». College Park, Md. : University of Maryland, 2009. http://hdl.handle.net/1903/9465.
Texte intégralRésumé :
Thesis (Ph.D.) -- University of Maryland, College Park, 2009.Thesis research directed by: Dept. of Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
40
Lecuyot, A. « Microcells for metastructures : An application of MicroSystem technology to distributed space structures ». Thesis, Cranfield University, 2004. http://hdl.handle.net/1826/1932.
Texte intégralRésumé :
In this thesis, a new concept of space systems called metastructures is studied. Applications are in very large space structures (1 km) that can take many shapes and be reconfigured during operations. This concept is explored by defining it from a systems engineering perspective, characterising the system dynamics and technical baseline, and assessing its interest with respect to proposed missions and to alternatives. Metastructures are defined as assemblies of microcells linked rigidly. Microcells are themselves defined as Nanosatellites with reduced functionalities, and are referenced locally or globally for active position control within the metastructure. Two reference missions are considered, a centimetric interferometer and a Solar concentrator as part of Solar Power systems. The methods used to analyse these missions and achieve the research objectives are based on strategy analysis, standard practices in mission and system design, and a simplified system dynamics simulation implemented in a custom simulator. The analysis of dynamics demonstrates the controllability of such structures, and their ability to maintain and keep shape in most orbits to good accuracy. It also shows that the design of the distributed controller is important. From this, subsystem requirements are derived for the microcells which are studied as highly integrated microsystems. Mass of the microcells is around 500 g, much of which is propellant. The baseline system configuration for reference missions is derived, including costing. For these missions masses are less than a ton, with costs less that 500 Million Euros. Metastructures do not perform well in terms of lifetime given the simplistic controller used. Appropriate research of decentralised controllers may remedy to this, but a weak point of the concept is that of stowing and launching. Finally, a preliminary analysis of the concept with respect to its alternatives tends to show that it is worthy of further investigation.
41
Lecuyot, Arnaud. « Microcells for metastructures : an application of microSystem technology to distributed space structures ». Thesis, Cranfield University, 2004. http://hdl.handle.net/1826/1203.
Texte intégralRésumé :
In this thesis, a new concept of space systems called metastructures is studied. Applications are in very large space structures (1 km) that can take many shapes and be reconfigured during operations. This concept is explored by defining it from a systems engineering perspective, characterising the system dynamics and technical baseline, and assessing its interest with respect to proposed missions and to alternatives.
Metastructures are defined as assemblies of microcells linked rigidly. Microcells are themselves defined as Nanosatellites with reduced functionalities, and are referenced locally or globally for active position control within the metastructure. Two reference missions are considered, a centimetric interferometer and a Solar concentrator as part of Solar Power systems.
The methods used to analyse these missions and achieve the research objectives
are based on strategy analysis, standard practices in mission and system design, and
a simplified system dynamics simulation implemented in a custom simulator.
The analysis of dynamics demonstrates the controllability of such structures, and
their ability to maintain and keep shape in most orbits to good accuracy. It also
shows that the design of the distributed controller is important.
From this, subsystem requirements are derived for the microcells which are studied
as highly integrated microsystems. Mass of the microcells is around 500 g, much
of which is propellant.
The baseline system configuration for reference missions is derived, including
costing. For these missions masses are less than a ton, with costs less that 500
Million Euros. Metastructures do not perform well in terms of lifetime given the
simplistic controller used. Appropriate research of decentralised controllers may
remedy to this, but a weak point of the concept is that of stowing and launching.
Finally, a preliminary analysis of the concept with respect to its alternatives
tends to show that it is worthy of further investigation.
42
Cheung, Siu Lun. « Attachment and Detachment of Circulating Tumor Cells in an Antibody-Functionalized Microsystem ». Diss., The University of Arizona, 2009. http://hdl.handle.net/10150/195478.
Texte intégralRésumé :
The attachment and detachment of circulating tumor cells in a functionalized microchannel under hydrodynamic loading have been studied. For the cell attachment experiments, EpCAM antibodies are immobilized on the microchannel surface to capture either PC3N prostate or MDA-MB-231 breast cancer cells from homogeneous cell suspensions. Using the same protocol, N-Cadherin antibodies are immoblilzed and used to study the detachment of target cancer cells captured in the microchannels.A critical flow rate Qc has been identified to characterize the kinetics of cell capture in a functionalized microchannel. Approaching one limit, when the receptor-ligand interaction dominates, more than 90% of moving cells can be captured and a sharp peak is observed in the spatial distribution of the captured cells. Approaching another limit, when hydrodynamic loading dominates, almost all cells cannot be captured in the channel. Between these two limits, there is a transition region in which both capture efficiency and cell distribution are sensitive to the flow parameters. Proper characteristic time and length scales have been identified to describe the cell spatial distribution using a log-normal statistical model. The kinetic details of cell capture are determined by the competition between the flow rate and the ligand-receptor association/dissociation rates.Additionally, the attachment dynamics of circulating tumor cells in a bio-functionalized microchannel under hydrodynamic loading has been explored. The target cells initially role along the microchannel with fluctuating velocity prior to firm adhesion. When a successful bond is established, the cancer cells require a certain length to come to a complete stop; this stopping length is found to depend linearly on the applied hydrodynamic flow rate. The force balance in the vertical cross stream direction is dominated by the gravitational force; as a result, all cells loaded into a microchannel intimately contact the functionalized channel bottom surface within a short time. The streamwise horizontal motion of the cells on the surface is dominated by the balance between the shear flow hydrodynamic loading and the receptor-ligand binding interaction. A linear spring element is incorporated in the physical model to represent the dynamics of a cancer cell captured by immobilized antibodies. Featuring a mobility matrix, a proposed theoretical model is utilized to estimate the binding and hydrodynamic forces acting on the cell in a microchannel. Inserting certain fitting parameters, the time evolution of a stopping cell is successfully predicted by a simplified exponential function.The mechanical response of a captured cancer cell to a hydrodynamic flow field is investigated and, in particular, the effect of flow acceleration is examined. The observed cell deformation is dramatic under low acceleration, but is negligible under high acceleration. Consequently, the detachment of captured cells depends on both flow rate and flow acceleration. The flow rate required for cell detachment is a random variable that can be described by a log-normal distribution. Two flow acceleration limits have been identified for proper scaling of the flow rate required to detach captured cells. A time constant on the order of 1min for the mechanical response of a captured cell has been identified for scaling the flow acceleration. Based on these acceleration limits and the time constant, an exponential-like empirical model is proposed to predict the flow rate required for cell detachment as a function of flow acceleration.
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Bengtsson, Katarina. « Design of a galvanotaxic track for cells, using polymer electrodes ». Thesis, Linköpings universitet, Institutionen för fysik, kemi och biologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-70081.
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Galvanotaxis is the movement of cells in an applied electric field. The first steps to design a chip for observations of galvanotaxic behavior of cells were done in this work. The chip is a miniaturised system of previous larger galvanotaxis systems and uses materials which are thought to be biocompatible. The system was constructed on microscope slides with a channel in PDMS with adjacent polymer electrodes. The polymer electrodes were made from poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS), glycerol and Silquest A-187. The PEDOT:PSS electrodes were connected with either an evaporated metal electrode of titanium and gold or a gold net. Systems with PEDOT:PSS are neutralised when put in excessive amount of PBS (pH=7.4) for 24 hours. The final system had a channel with dimension length=14 mm, width=0.5 mm and height=0.25 mm. PEDOT:PSS worked as an electrode material and the achieved electric field through the channel was between 55 V/m and 160 V/m with an applied voltage of 1 V. The decrease of the electric field within the first hour was between 10 % and 30%. Further development of this system could give an easy way to observe galvanotaxic behaviour of cells or an instrument that can distinguish between different cell types.
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Pardon, Gaspard. « A feasibility Study of SMA Powder Composite Actuators ». Thesis, KTH, Mikrosystemteknik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-91283.
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JOHANSSON, SIMON, et EMIL LENNGREN. « Steganographic embedding and steganalysisevaluation : An evaluation of common methods for steganographic embedding and analysis indigital images ». Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157499.
Texte intégralRésumé :
Steganography is the technique that hides secret messages in seemingly inoccuous data. Steganalysis is the technique that is used to discover the use of steganography. Usuallyit is difficult to extract the exact hidden message because itis usually encrypted. Though often it is enough to merely uncover the use of steganography to reveal important information.In this report we discuss some common methods for steganography in images, as well as some methods of analysis,both general and targeted towards specific methods. We test how well the methods fare against each other and what one should consider when making use of steganography. According to our results, many steganographic methods need targeted analysis attacks to be discovered. Our advice is to avoid using the full potential capacity when embeddingdata. The hidden data should also be distributed randomly in the cover file.
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Zhang, Zheng. « Explorations in Word Embeddings : graph-based word embedding learning and cross-lingual contextual word embedding learning ». Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLS369/document.
Texte intégralRésumé :
Les plongements lexicaux sont un composant standard des architectures modernes de traitement automatique des langues (TAL). Chaque fois qu'une avancée est obtenue dans l'apprentissage de plongements lexicaux, la grande majorité des tâches de traitement automatique des langues, telles que l'étiquetage morphosyntaxique, la reconnaissance d'entités nommées, la recherche de réponses à des questions, ou l'inférence textuelle, peuvent en bénéficier. Ce travail explore la question de l'amélioration de la qualité de plongements lexicaux monolingues appris par des modèles prédictifs et celle de la mise en correspondance entre langues de plongements lexicaux contextuels créés par des modèles préentraînés de représentation de la langue comme ELMo ou BERT.Pour l'apprentissage de plongements lexicaux monolingues, je prends en compte des informations globales au corpus et génère une distribution de bruit différente pour l'échantillonnage d'exemples négatifs dans word2vec. Dans ce but, je précalcule des statistiques de cooccurrence entre mots avec corpus2graph, un paquet Python en source ouverte orienté vers les applications en TAL : il génère efficacement un graphe de cooccurrence à partir d'un grand corpus, et lui applique des algorithmes de graphes tels que les marches aléatoires. Pour la mise en correspondance translingue de plongements lexicaux, je relie les plongements lexicaux contextuels à des plongements de sens de mots. L'algorithme amélioré de création d'ancres que je propose étend également la portée des algorithmes de mise en correspondance de plongements lexicaux du cas non-contextuel au cas des plongements contextuelsWord embeddings are a standard component of modern natural language processing architectures. Every time there is a breakthrough in word embedding learning, the vast majority of natural language processing tasks, such as POS-tagging, named entity recognition (NER), question answering, natural language inference, can benefit from it. This work addresses the question of how to improve the quality of monolingual word embeddings learned by prediction-based models and how to map contextual word embeddings generated by pretrained language representation models like ELMo or BERT across different languages.For monolingual word embedding learning, I take into account global, corpus-level information and generate a different noise distribution for negative sampling in word2vec. In this purpose I pre-compute word co-occurrence statistics with corpus2graph, an open-source NLP-application-oriented Python package that I developed: it efficiently generates a word co-occurrence network from a large corpus, and applies to it network algorithms such as random walks. For cross-lingual contextual word embedding mapping, I link contextual word embeddings to word sense embeddings. The improved anchor generation algorithm that I propose also expands the scope of word embedding mapping algorithms from context independent to contextual word embeddings
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Hauser, Bruno. « Embedding proof-carrying components into Isabelle ». Zurich : ETH, Swiss Federal Institute of Technology Zurich, Institute of Theoretical Computer Science, Chair of Software Engineering, 2009. http://e-collection.ethbib.ethz.ch/show?type=dipl&nr=436.
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Lam, Ioi Tun. « Biometric watermark embedding in document images ». Thesis, University of Macau, 2009. http://umaclib3.umac.mo/record=b2130131.
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Kayo, O. (Olga). « Locally linear embedding algorithm:extensions and applications ». Doctoral thesis, University of Oulu, 2006. http://urn.fi/urn:isbn:9514280415.
Texte intégralRésumé :
Abstract
Raw data sets taken with various capturing devices are usually multidimensional and need to be preprocessed before applying subsequent operations, such as clustering, classification, outlier detection, noise filtering etc. One of the steps of data preprocessing is dimensionality reduction. It has been developed with an aim to reduce or eliminate information bearing secondary importance, and retain or highlight meaningful information while reducing the dimensionality of data.
Since the nature of real-world data is often nonlinear, linear dimensionality reduction techniques, such as principal component analysis (PCA), fail to preserve a structure and relationships in a highdimensional space when data are mapped into a low-dimensional space. This means that nonlinear dimensionality reduction methods are in demand in this case. Among them is a method called locally linear embedding (LLE), which is the focus of this thesis. Its main attractive characteristics are few free parameters to be set and a non-iterative solution avoiding the convergence to a local minimum. In this thesis, several extensions to the conventional LLE are proposed, which aid us to overcome some limitations of the algorithm. The study presents a comparison between LLE and three nonlinear dimensionality reduction techniques (isometric feature mapping (Isomap), self-organizing map (SOM) and fast manifold learning based on Riemannian normal coordinates (S-LogMap) applied to manifold learning. This comparison is of interest, since all of the listed methods reduce high-dimensional data in different ways, and it is worth knowing for which case a particular method outperforms others.
A number of applications of dimensionality reduction techniques exist in data mining. One of them is visualization of high-dimensional data sets. The main goal of data visualization is to find a one, two or three-dimensional descriptive data projection, which captures and highlights important knowledge about data while eliminating the information loss. This process helps people to explore and understand the data structure that facilitates the choice of a proper method for the data analysis, e.g., selecting simple or complex classifier etc. The application of LLE for visualization is described in this research.
The benefits of dimensionality reduction are commonly used in obtaining compact data representation before applying a classifier. In this case, the main goal is to obtain a low-dimensional data representation, which possesses good class separability. For this purpose, a supervised variant of LLE (SLLE) is proposed in this thesis.
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Alhashem, Mustafa. « The book embedding of ordered sets ». Thesis, University of Ottawa (Canada), 2005. http://hdl.handle.net/10393/26835.
Texte intégralRésumé :
A large number of important problems in different areas can be expressed as graph layout problems whose objective is to determine a linear layout in such way that a certain objective cost is optimized. In a book embedding for an ordered set, the elements are embedded on the spine of the book to form a linear extension. The pagenumber is the minimum number of pages needed to draw the edges as simple curves such that edges drawn in the same page do not intersect. The book (stack) layout can be applied to several areas of computer science and engineering disciplines including ordered sets, interconnection networks, fault tolerant VLSI design, circuit designs, sorting permutations, complexity theory, and graph drawing.
In this thesis we investigate the book (stack) layout problem of ordered sets. The pagenumber problem is known to be NP-complete, even if the order of the elements on the spine is fixed. As a result, the pagenumber problem has been studied only for some restricted classes of ordered sets. A literature review on the pagenumber problem for graphs and ordered sets is presented. We also provide the first efficient algorithm for drawing the bipartite interval orders in the minimum number of pages needed. We also give an upper bound for the pagenumber of bipartite ordered sets and the pagenumber of the complete multipartite ordered sets with length 4 and 5.