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1
O'Sullivan, Donald Quinn 1970. "Aircraft interior structural-acoustic control design." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9888.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering; and, (S.M.)--Massachusetts Institute of Technology, Technology and Policy Program, 1998.Includes bibliographical references (p. 177-184).
by Donald Quinn O'Sullivan.
S.M.
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Behkami, Nima A. "Examining Health Information Technology Implementations: Case of the Patient-Centered Medical Home." PDXScholar, 2012. https://pdxscholar.library.pdx.edu/open_access_etds/237.
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It has been shown that the use of Health Information Technology (HIT) is associated with reduced cost and increased quality of care. This dissertation examined the use of registries in Patient Centered Medical Home (PCMH) practices. A survey questionnaire was sent to a nationwide group of clinics certified for being a PCMH. They were asked to provide information about their payer mix, implementation barriers, registry implementation, registry use, and clinic satisfaction. The survey instrument was validated by an expert panel which included practitioners and researchers. Statistical methods including Structural Equation Modeling were used for analysis and to test the research hypotheses. The majority of medical home practices that responded used some type of computerized registry, either with basic patient information or integrated with detailed clinical information. And on average, they somewhat used registries for population management, individual health management, proactive care and planned care visits. All practices encountered some combination of barriers when implementing a medical home program. Most practices reported clinic satisfaction at least improved after becoming a medical home. The results of the analysis show that indeed payer mix, in particular Medicare and private insurance, has a significant relationship with level of registry implementation. There were no significant relationships between barriers and registry implementation or use. More sophisticated registry implementation led to greater registry use. And registry use is associated with increased clinic satisfaction. This research fills an important gap in understanding Health IT use, registries in particular, among Patient-Centered Medical Homes. The findings suggest that: 1) Implementation barriers may not be influencing use of computerized registries in medical home practices; 2) Using more sophisticated computerized registries facilitates registry use, which can help improve clinic satisfaction; 3) Payer mix may influence use of more sophisticated Health IT in medical home practices.
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Dahan, Frédéric. "Qualification d'un systeme de controle acoustique structural actif." Aix-Marseille 2, 1996. http://www.theses.fr/1996AIX22110.
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Dans le domaine de la prediction, la modelisation numerique en vibro-acoustique (en regime harmonique) est exploitee pour etudier les systemes d'absorption active. L'etude porte sur le controle acoustique structural qui agit sur la structure a l'origine du bruit a supprimer. Or, cette methode conduit souvent a une amplification des vibrations structurales (effet spillover). Comment definir et qualifier un dispositif actionneurs/capteurs qui, a partir d'un controle local par anticipation de type lms, attenue efficacement le rayonnement global sans effet spillover ? en premier lieu, nous montrons que la sensibilite des mecanismes de controle s'oppose a la resolution modale du probleme. En revanche, une approche globale permet d'obtenir un dispositif qui atteint l'objectif fixe. La formulation dans l'espace des commandes, aide a definir une configuration d'actionneurs avec une commande ideale qui tient compte de la connaissance du modele. Il est demande ensuite a un nombre fini de senseurs d'estimer cette commande. Deux approches sont developpees. La premiere reside dans la definition d'un filtrage sur des capteurs de position predeterminee et la seconde sur l'optimisation des positions des senseurs. Avec la seconde methode, les capteurs sont places sur les nuds du champ residuel ideal. Ce resultat est analyse lorsque les nuds sont absents, puis valide experimentalement. La demarche proposee presente l'inconvenient d'etre tributaire du champ primaire. Nous proposons alors un moyen de discriminer les dispositifs de controle relativement a leur robustesse aux variations du champ primaire. La methode globale est finalement inseree dans un modele numerique de la cabine d'un avion couplee a son fuselage. Le nombre important de degres de liberte du modele elements finis suppose un traitement des operations pour reduire les temps de calcul. Les resultats obtenus fournissent des informations interessantes sur les mecanismes de controle d'une cavite vibrante
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Redmond, Brian L. "A workcell control and communications structure for the Georgia Institute of Technology Flexible Automation Laboratory." Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/18946.
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Øslebø, Arne. "A diagrammatic notation for modeling access control in tree-based data structures." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for telematikk, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-2195.
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This thesis describe two graphical modeling languages that can be used for specifying the access control setup in most systems that store information in a tree based structure. The Tree-based Access control Modeling Language (TACOMA) is the simplest language that is defined. It is easy to learn and use as it has only 8 symbols and two relations. With this language it is possible to define the exact access control rules for users using a graphical notation. The simplicity of the language do however come at a cost: it is best suited for small or medium sized tasks where the number of users and objects being controlled are limited. To solve the scalability problem a second language is also presented. The Policy Tree-based Access control Modeling Language (PTACOMA) is a policy based version of TACOMA that doubles the number of symbols and relations. While it is harder to learn it scales better to larger tasks. It also allows for distributed specification of access rules where administrators of different domains can be responsible for specifying their own access control rules. Domains can be organized in a hierarchical manner so that administrators on a higher level can create policies that have higher priority and therefor limits what administrators at lower levels can do. The thesis describes the two languages in detail and provides a comparison between them to show the strong and weak points of each language. There is also a detailed case study that shows how the two languages can be used for specifying access control in SNMPv3.
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Zare, Firuz. "Multilevel converter structure and control." Thesis, Queensland University of Technology, 2001. https://eprints.qut.edu.au/36142/7/36142_Digitsed%20Thesis.pdf.
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In recent years, multilevel converters are becoming more popular and attractive than traditional converters in high voltage and high power applications. Multilevel converters are particularly suitable for harmonic reduction in high power applications where semiconductor devices are not able to operate at high switching frequencies or in high voltage applications where multilevel converters reduce the need to connect devices in series to achieve high switch voltage ratings. This thesis investigated two aspects of multilevel converters: structure and control.
The first part of this thesis focuses on inductance between a DC supply and inverter components in order to minimise loop inductance, which causes overvoltages and stored energy losses during switching. Three dimensional finite element simulations and experimental tests have been carried out for all sections to verify theoretical developments. The major contributions of this section of the thesis are as follows:
The use of a large area thin conductor sheet with a rectangular cross section separated by dielectric sheets (planar busbar) instead of circular cross section wires, contributes to a reduction of the stray inductance. A number of approximate equations exist for calculating the inductance of a rectangular conductor but an assumption was made that the current density was uniform throughout the conductors. This assumption is not valid for an inverter with a point injection of current. A mathematical analysis of a planar bus bar has been performed at low and high frequencies and the inductance and the resistance values between the two points of the planar busbar have been determined.
A new physical structure for a voltage source inverter with symmetrical planar bus bar structure called Reduced Layer Planar Bus bar, is proposed in this thesis based on the current point injection theory. This new type of planar busbar minimises the variation in stray inductance for different switching states. The reduced layer planar busbar is a new innovation in planar busbars for high power inverters with minimum separation between busbars, optimum stray inductance and improved thermal performances. This type of the planar busbar is suitable for high power inverters, where the voltage source is supported by several capacitors in parallel in order to provide a low ripple DC voltage during operation.
A two layer planar busbar with different materials has been analysed theoretically in order to determine the resistance of bus bars during switching. Increasing the resistance of the planar busbar can gain a damping ratio between stray inductance and capacitance and affects the performance of current loop during switching. The aim of this section is to increase the resistance of the planar bus bar at high frequencies (during switching) and without significantly increasing the planar busbar resistance at low frequency (50 Hz) using the skin effect. This contribution shows a novel structure of busbar suitable for high power applications where high resistance is required at switching times.
In multilevel converters there are different loop inductances between busbars and power switches associated with different switching states. The aim of this research is to consider all combinations of the switching states for each multilevel converter topology and identify the loop inductance for each switching state. Results show that the physical layout of the busbars is very important for minimisation of the loop inductance at each switch state. Novel symmetrical busbar structures are proposed for multilevel converters with diode-clamp and flying-capacitor topologies which minimise the worst case in stray inductance for different switching states. Overshoot voltages and thermal problems are considered for each topology to optimise the planar busbar structure.
In the second part of the thesis, closed loop current techniques have been investigated for single and three phase multilevel converters. The aims of this section are to investigate and propose suitable current controllers such as hysteresis and predictive techniques for multilevel converters with low harmonic distortion and switching losses. This section of the thesis can be classified into three parts as follows:
An optimum space vector modulation technique for a three-phase voltage source inverter based on a minimum-loss strategy is proposed. One of the degrees of freedom for optimisation of the space vector modulation is the selection of the zero vectors in the switching sequence. This new method improves switching transitions per cycle for a given level of distortion as the zero vector does not alternate between each sector. The harmonic spectrum and weighted total harmonic distortion for these strategies are compared and results show up to 7% weighted total harmonic distortion improvement over the previous minimum-loss strategy. The concept of SVM technique is a very convenient representation of a set of three-phase voltages or currents used for current control techniques.
A new hysteresis current control technique for a single-phase multilevel converter with flying-capacitor topology is developed. This technique is based on magnitude and time errors to optimise the level change of converter output voltage. This method also considers how to improve unbalanced voltages of capacitors using voltage vectors in order to minimise switching losses. Logic controls require handling a large number of switches and a Programmable Logic Device (PLD) is a natural implementation for state transition description. The simulation and experimental results describe and verify the current control technique for the converter.
A novel predictive current control technique is proposed for a three-phase multilevel converter, which controls the capacitors' voltage and load current with minimum current ripple and switching losses. The advantage of this contribution is that the technique can be applied to more voltage levels without significantly changing the control circuit. The three-phase five-level inverter with a pure inductive load has been implemented to track three-phase reference currents using analogue circuits and a programmable logic device.
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Sourdille, Etienne. "Numerical simulation and control of a fluid structure interaction for a plate in a transverse flow." Thesis, University of Southampton, 2006. https://eprints.soton.ac.uk/47114/.
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The control of a moving structure in an unbounded flow has numerous applications in engineering, such as the aileron on an airplane. Here an approach is proposed where a CFD method is coupled with a controller to provide a qualitative flow model, and a tool for the development and the validation of the control scheme. A rotating rigid flat plate in transverse flow is considered. For the CFD, a discrete vortex method is used due to its relevance for separated flows, which implies approximating the flat plate by a thin ellipse. The simulation for a fixed plate has been completed with a plate approximated by a 20:1 ellipse and placed in an inviscid flow. A comparison with an image method is also undertaken. The results show encouraging features for modelling the vortex street, but also problems in the transient behaviour of the flow. The control method is based on fuzzy logic, and has shown a remarkable ability to adapt to the nonlinear nature of the force generated by the flow/structure system. Comparison is made with more classical schemes such as a controller based on optimal control theory using an intermediary flow/structure model, similar to a gain scheduling model, instead of the full simulation.
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Srinivas, Preethi. "Private Key Allocation based Access Control Scheme for Social Networks." Miami University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=miami1281839737.
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Cowan, Thomas C. S. B. Massachusetts Institute of Technology. "Network control in a globalized world : how Visa and Swift's founding structures serve their stakeholders on the International stage." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/112017.
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Thesis: S.B., Massachusetts Institute of Technology, Program in Science, Technology and Society, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 51-55).
The Visa credit card network and the Society for Worldwide Interbank Financial Telecommunications (Swift) network both provide a backbone for financial interchange across the world. Visa's network connects consumers, merchants, banks, and processors to ease the purchases of millions of consumer-facing products worldwide. Swift's interbank network connects banks, corporates, and other financial institutions to ease the flow of high-value, highly-secure international financial transactions. Both networks grew to become industry incumbents in the second half of the 20th century, connecting nearly every country on earth. However, the globalized networks differ in their organizational structures: Visa utilizes a centralized, U.S. focused, hub-and-spoke model; Swift uses a decentralized, transaction-volume neutral, point-to-point network. Although Visa's centralized network fosters innovation, standardization, and security, its U.S.-centered hub pulls the organization from global neutrality and aligns it with the United States on global issues. Meanwhile, although Swift's decentralized network nurtures technological localization-at the expense of technological standardizationits transaction-based global governing structure promotes a relative international neutrality among global organizations. This contrast between Visa and Swift-both networks that balance local and global, centralized and decentralized, and technical and non-technical tensions across the world-reveals the structural effects of worldwide networks, and how network system design impacts global stakeholders in the societies that they touch.
by Thomas C. Cowan.
S.B.
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Li, Kaixiang. "Structural vibration damping with synchronized energy transfer between piezoelectric patches." Phd thesis, INSA de Lyon, 2011. http://tel.archives-ouvertes.fr/tel-00735788.
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Advanced materials such as carbon fiber, composite materials et al. are more and more used in modern industry. They make the structures lighter and stiffer. However, they bring vibration problems. Researchers studied numerous methods to eliminate the undesirable vibrations. These treatments are expected to be a compact, light, intellectual and modular system. Recently, a nonlinear technique which is known as Synchronized Switch Damping (SSD) technique was proposed. These techniques synchronously switched when structure got to its displacement extremes that leading to a nonlinear voltage on the piezoelectric elements. This resulting voltage showed a time lag with the piezoelectric strain thus causing energy dissipation. Based on the developed SSD techniques, a new synchronized switch damping e.g. Synchronized Switch Damping with Energy Transfer (SSDET) was proposed in this document. This method damped the vibration by using the energy from other vibrating form. The objectives of the work reported in this document were threefold. The first one consisted of introduction of SSDET principle and developing its control law. This part aimed at establishing the mathematical model and verifying the proposed method by mathematical tools. Then, the experimental validations were carried out. Three experiments with different configurations demonstrated that SSDET can be implemented not only between structures but also vibrating modes in one structure. A SSDET scheme with multi-patches was also investigated for improving the damping. Finally, a bidirectional SSDET concept was introduced based on the original SSDET technique. This technique be regarded as a multimode control SSDET. Since it privileged the target vibration while keeps a decent control effect on the source vibration.
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Audrain, Pascal. "Contrôle actif de l'intensité structurale dans une poutre." Le Mans, 2001. http://cyberdoc.univ-lemans.fr/theses/2001/2001LEMA1009.pdf.
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Cette étude porte sur la réduction des vibrations dans les structures unidimensionnelles à l'aide d'une méthode de contrôle actif. La stratégie retenue consiste à minimiser le transfert d'énergie transmis par les ondes de flexion et d'extension. Les champs vibratoires évanescents sont pris en ompte dans l'algorithme qui est développé pour le contrôle de l'intensité structurale en temps réel. Pour la réalisation de ce contrôle l'intensité doit être extraite à partir du traitement du signal en provenance de plusieurs capteurs. Dans cet objectif, une sonde intensimétrique composée de capteurs PVDF est mise en place. Ces capteurs présentent l'avantage de s'intégrer à la structure. Undéveloppement en ondes est utilisé pour décrire les champs de déplacement et ainsi calculer le transfert d'énergie dans la structure. Un schéma de contrôle actif optimal de cette grandeur énergétique est formulé. Les simulations numériques permettent d'évaluer les performances théoriques de cette stratégie. La validation expérimentale de cette approche est réalisée à partir d'une poutre libre-libre et d'une structure plus complexe constituée d'une poutre et d'une plaque. Un algorithme des moindres carrés moyens à référence filtrée est modifié dans le but de minimiser l'intensité structurale instantanée associée aux ondes de flexion et d'extension. Mais une restriction provient de la nature même de l'intensité qui n'est pas une erreur quadratique définie positive en général. L'approche est donc limitée à des géométries pour les quelles les transferts d'énergie générés par la perturbation et les sources de contrôle ont le même signe au niveau du capteur d'erreur. Pour la mesure et le contrôle de l'intensité structurale, un schéma de différences finies utilisant des capteurs PVDF de déformation est présenté et validé expérimentalement. Les résultats obtenus montrent que cette stratégie peut être envisagée dans le cadre d'un contrôle actif du transfert vibratoireThis thesis deals with active vibration control in one dirnensional structures. The control of flexural and extensional structural power flow is investigated. The instantaneous intensity is completely taken into account in the control algorithm, i. E. All the terms are considered in the real-time control process and, in particular, the evanescent waves are considered in this approach. The structural intensity has to be calculated from signals measured by several sensors. To do so, an intensity probe rnade of PVDF strain sensors is developped. The PVDF sensors are well suited for integration into structure in order to realize smart structures. A wave decomposition of the displacement field is used to calculate the structural power flow. A structural intensity optimal active control scheme is formulated and the numerical simulations illustrate the performance of this strategy. Experimental validation of the approach is conducted on a free-free beam and on a beam connected to a plate. A feedforward filtered-X LMS algorithm is adapted to control instantaneous intensity associated with flexural and extensional waves. This energy-based control problem involves a non-positive definite quadratic form in general. In this respect, the approach is limited to cases where the geometry is such that the intensity component will have the same sign for the control source and the primary disturbance. A finite difference scheme using PVDF strain sensors is presented and validated to measure and control structural power flow. The results show this strategy can be used to control vibration transfert in structures
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Chalvet, Vincent. "Conception, réalisation et commande d'un microrobot numérique, planaire, non-redondant et en technologie MEMS." Phd thesis, Université de Franche-Comté, 2013. http://tel.archives-ouvertes.fr/tel-00913321.
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Le développement récent en micro- et nano-technologies (dans des domaines tels que l'horlogerie, l'électronique, l'optique, le biomédical, . . .) a créé un fort besoin concernant des systèmes capables de manipuler et d'assembler des objets de plus en plus petits. La conception de stations robotisées, capables de manipuler des micro-objets, s'est multipliée à travers le monde, faisant intervenir des actionneurs de haute résolution adaptés au micromonde, ainsi que de nombreux capteurs. Ce mémoire ouvre une nouvelle voie pour le développement de robots de micromanipulation. Il présente la conception, la modélisation, la fabrication et la commande d'un nouveau concept de microrobot, le DiMiBot (Digital MicroroBot). Il s'agit du premier microrobot numérique - inspiré de l'électronique numérique - qui fait intervenir des actionneurs binaires pour générer un déplacement discret d'une grande précision sans nécessiter de capteur (en boucle ouverte). Ces actionneurs binaires extrêmement répétables et robustes (les modules bistables), assurent chacun un déplacement précis de 25 μm. Ils sont associés de manière monolithique à une architecture robotique parallèle flexible, assurant la génération d'un espace de travail discret, dont les 2N (N est le nombre de modules bistables utilisés au sein du DiMiBot) positions distincts atteignables sont parfaitement stables, répétables et robustes mécaniquement. Elles sont réparties de manière homogène dans un carré de10,5 μm de côté. La microfabrication du premier prototype de microrobot numérique en silicium - faisant suite à un dimensionnement minutieux en éléments finis - a été réalisé au sein de la salle blanche MIMENTO de l'institut FEMTO-ST. Ce DiMiBot possédant 4 modules bistables assure une résolution de 3,5 μm pour une répétable de chacune des 16 positions atteignables de 90 nm.
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Nwankwo, Cosmas Chidozie. "Smart offshore structure for reliability prediction process." Thesis, Cranfield University, 2013. http://dspace.lib.cranfield.ac.uk/handle/1826/9335.
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A review of the developments within the field of structural reliability theory shows that
some gaps still exist in the reliability prediction process and hence there is an urgent
desire for improvements such that the estimated structural reliability will be capable of
expressing a physical property of the given structure. The current reliability prediction
process involves the continuous estimation and use of reliability index as a way of
estimating the safety of any given structure. The reliability index β depends on the
Probability Density Function (PDF) distribution for the wave force and the corresponding
PDF of resistance from respective structural members of the given structure. The PDF
for the applied wave force will depend on the PDF of water depth, wave angular velocity
and wave direction hence the reliability index as currently practiced is a statistical way
of managing uncertainties based on a general probabilistic model.
This research on Smart Offshore Structure for Reliability Prediction has proposed the
design of a measurement based reliability prediction process as a way of closing the
gap on structural reliability prediction process. Structural deflection and damping are
some of the measurable properties of an offshore structure and this study aims at
suggesting the use of these measurable properties for improvements in structural
reliability prediction process. A design case study has shown that a typical offshore
structure can deflect to a range of only a few fractions of a millimetre. This implies that if
we have a way of monitoring this level of deflection, we could use the results from such
measurement for the detection of a structural member failure. This advocated concept is
based on the hypothesis that if the original dynamic characteristics of a structure is
known, that measurement based modified dynamic properties can be used to determine
the onset of failure or failure propagation of the given structure.
This technology could reveal the location and magnitude of internal cracks or corrosion
effects on any given structure which currently is outside the current probability based
approach. A simple economic analysis shows that the recommended process shows a
positive net present value and that some $74mln is the Value of Information for any life
extension technology that could reveal the possibility of extending the life of a given
10,000bopd production platform from 2025 to 2028.
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Yon, Jean-Jacques. "Oxydation du silicium poreux : application à la réalisation de structures silicium sur isolant." Grenoble 1, 1986. http://www.theses.fr/1986GRE10028.
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Des structures silicium sur isolant (soi) peuvent etre obtenues a partir de silicium poreux a condition de controler l'oxydation thermique du materiau. Ce memoire est consacre a l'etude de l'oxydation du silicium poreux. Ce travail a permis de fixer les conditions experimentales conduisant a la formation reproductible de couches de silicium poreux homogenes. L'etude detaillee de l'oxydation de ce materiau a permis de degager un mecanisme phenomenologique qui rend compte de la transformation du silicium poreux en oxyde aux proprietes identiques a celles de la silice classique. Le mecanisme procede par une oxydation chimique couplee a une densification, tres activee en temperature, de la silice. Ces resultats ont ete appliques a la realisation de structures soi
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Beneitez, Miguel, and Johan Sundin. "Turbulent flow control via nature inspired surface modifications." Thesis, KTH, Mekanik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206189.
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Many of the flows in nature are turbulent. To modify turbulent flows, nature serves itself with different types of coatings. Sharks have riblets-like structures on their skin, fishes have slime with polymers and the surface of the lotus flower has superhydrophobic properties. However many times these naturally occurring coatings also serve other purposes. Due to millions of years of adaption, there are anyway many reasons to be inspired by these. The present work is an investigation of nature inspired coatings with the aim of passive flow manipulations. The goal of the investigation has not been to achieve drag reduction, but to achieve a better understanding of the effect of these coatings on turbulent flows. Simulations have been performed in a channel flow configuration, where the boundary condition on one wall has been modified. A macroscopic description has been used to simulate superhydrophobic and porous-like surfaces and a microscopic description has been used to simulate suspended fibers, both rigid and flexible, attached to the channel wall. For the macroscopic description, a pseudo-spectral method was used and for the microscopic description a lattice-Boltzmann method was used. The superhydrophobic modification was implemented using a general slip tensor formulation. In agreement with earlier results, drag reduction was achieved with slip in the streamwise direction and slip in the spanwise direction resulted in drag increase. Non-zero off-diagonal terms in the slip tensor resulted in a slight drag increase, but with rather similar flow behaviour. Transpiration, imitating a porous media, gave rise to drag increase and severely modified the turbulent structures, forming two-dimensional structures elongated in the spanwise direction. For the short fibers, neither rigid nor flexible fibers modified the velocity field to a large extent. The fibers gave rise to recirculation regions and these were seen to be stronger below high-speed streaks. Flexible fibers showed similarities to porous media through a coupling of wallnormal velocity and pressure fluctuations, and this was not seen for the rigid fibers. The fiber deflections were seen to correlate well with the pressure fluctuations.Många naturligt förekommande flöden är turbulenta. Naturen har också gett upphov till flera typer av ytskikt som kan påverka dessa. Hajars skinn har räfflor, fiskar har slem som innehåller polymerer och lotusblommans yta har superhydrofobiska egenskaper, men ofta har dessa naturliga ytskikt också andra egenskaper. På grund av miljoner år av anpassning så finns det ändå många skäl att studera dessa. Detta arbete är en studie av naturinspirerade ytskikt, där målet har varit passiva flödesmanipulationer. Målet har inte varit att åstadkomma en ytfriktionsminskning, utan att få en bättre förståelse om hur dessa ytskikt påverkar turbulenta flöden. Simuleringar har utförts i en kanalliknande geometri, där en kanalväggs randvillkor har modifierats. En makroskopisk beskrivning har använts för att simulera superhydrofobiska och porösa ytor och en mikroskopisk beskriving har använts för att simulera fibrer, både stela och böjbara, fastsatta på en kanalvägg. För flödet med det makroskopiskt beskrivna randvillkoret har en pseudospektral metod använts och för flödet med det mikroskopiskt beskrivna randvillkoret har en lattice-Boltzmannmetod använts. Den superhydrofobiska ytan implementerades genom en generell tensorformulering. Ett randvillkor med nollskild hastighet i kanalens riktning gav upphov till en ytfriktionsminskning och ett randvillkor med nollskild hastighet vinkelrät mot kanalens riktning gav upphov till en ökad ytfriktion, i överensstämmelse med tidigare resultat. Nollskilda icke-diagonala tensorelement gav upphov till en smärre ökning av ytfriktionen, utan att nämnvärt förändra flödet. De porösa ytorna gav upphov till en ytfriktionsökning och hade stor inverkan på de turbulenta strukturerna. Dessa ytor bildade tvådimensionella struturer vinkelrät mot kanalens riktning. Varken de stela eller de böjbara fibrerna gav upphov till stora ändringar i hastighetsfältet. Däremot uppstor cirkulationszoner och dessa var starkare under stråkstrukturer med hög hastighet. De böjbara fibrerna uppvisade likheter med porösa material genom en interaktion mellan det vertikala hastighetsfältet och de turbulenta tryckfluktuationerna. Denna interaktion uppstod inte för de stela fibrerna. Fibrernas böjning korrelerade också i stor utsträckning till tryckfluktuationerna.
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Johansson, Andreas. "Bitefficient Coding Methods for Low Bitrate MPEG-1/MPEG-2 Encoders." Thesis, Linköping University, Department of Electrical Engineering, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-744.
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The packing and coding of digital video is a part of science where much innovation has taken place during the last few decades. The MPEG standards of video encoding are some of the most well-known and used video coding standards today. Since MPEG defines exact requirements for the decoder, but not the encoder, encoders can be made in many different ways and levels of complexity, as long as they produce legal MPEG streams that can be viewed on any MPEG-conformant decoder. This thesis will examine the possible performance of MPEG, in particular MPEG-1/MPEG-2 full TV resolution (720*576), for coding video at bitrates significantly lower than the 2-15 Mb/s MPEG-2 originally was designed for. For this purpose, encoding methods previously proposed by various researchers are presented. Furthermore a few new algorithms, which can be used for MPEG coding in general, but was constructed with a low-bitrate encoder in mind, were developed. Finally objective video quality benchmarks were conducted and the results evaluated.
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Jemai, Brahim. "Contrôle actif de structures flexibles à l'aide de matériaux piezo-électriques : Applications." Ecully, Ecole centrale de Lyon, 1999. http://www.theses.fr/1999ECDL0023.
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Un système mécanique donné est dépendant de son environnement au moment de son fonctionnement. Cet environnement est caractérisé par l'ensemble des sources d'excitations, les liaisons et les effets indésirables tels que les bruits et les vibrations que produit la structure. Un tel système évolue selon des lois naturelles positives et globales. Le contrôle actif a pour objectif d'agir sur ces lois et permet de conférer au système un comportement avec de meilleures performances dynamiques. Pour ce faire on intègre à la structure de base un jeu de capteurs pour mesurer son état vibratoire et un jeu d'actionneurs pour appliquer une commande générée par un contrôleur afin d'amener la structure à un état fixé auparavant. Dans ce travail, il s'agit d'étudier le contrôle actif de structures légères et flexibles à l'aide de matériaux piezoélectriques. En effet, ces structures sont abondamments utilisées en construction aéronautique. Un problème fondamental se pose lors du contrôle de telles structures : c'est le phénomène de la contamination modale (effet de Spillover) qui se manifeste sous forme d'instabilitésA given mechanical system is dependant on its environment at the time of its operation. The excitation sources and the connections with its environment makes the system produces adverse effects such as the noises and the vibrations. Such a system behaves according to positive and total natural laws'. Active control aims to act on these laws and makes it possible to confer on the system a behavior with better dynamic performances. With this intention one integrates into the basic structure a set of sensors to measure its vibratory state and a set of actuators to apply a command generated by a controller in order to bring the structure in a state fixed before. In this work, it is a question of studying the active control of light and flexible structures using peizoelectric materials. These structures are abundantly used in aeronautical construction. A fundamental problem arises during the control of such structures : it is the phenomenon of the modal contamination (effet Spillower) which occurs as instabilities
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Al-Soudani, Maha. "Diagnosis of reinforced concrete structures in civil engineering by GPR technology : development of alternate methods for precise geometric recognition." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30090.
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La méconnaissance de la géométrie réelle d'une structure mène à une évaluation incorrecte de son état. Par conséquent, une estimation imprécise de sa capacité portante, sa durabilité, sa stabilité et la nécessité de mettre en place une réparation ou un renforcement. En outre, l'optimisation du temps requis pour le processus de réparation a besoin de bien connaître les différentes parties de la structure à évaluer et également pour éviter les zones critiques telles que les aciers, les câbles, etc., lors de la réparation. Par conséquent, il est nécessaire d'utiliser des techniques d'évaluation non destructive (END) afin de connaître la géométrie réelle de la structure, notamment l'emplacement des armatures dans les structures en béton armé. Le GPR est considéré comme une technique non-destructive idéale pour détecter et localiser les renforts. Cependant, sa précision de localisation est limitée. Le but de ce projet de recherche a donc été d'accroître la précision du GPR en matière de reconnaissance géométrique interne de structures en béton armé. L'objectif principal de cette étude est de localiser précisément le positionnement des armatures dans le plan ausculté ainsi qu'en profondeur. Pour atteindre cet objectif, une nouvelle méthodologie de mesures et du traitement des signaux GPR a été proposée dans cette étude. Plusieurs configurations d'acquisition de données en utilisant des signaux simulés sont testées pour proposer et développer un algorithme d'imagerie du milieu de propagation afin de définir sa géométrie interne et de localiser précisément les barres de renforcement. Des traitements supplémentaires sont appliqués pour améliorer la précision de la détection et pour identifier les différentes interfaces dans le milieu testé. L'algorithme et le traitement sont appliqués aux signaux simulés. Des validations expérimentales ont ensuite été appliquées aux signaux réels acquis sur différentes dalles en béton armé. L'objectif est de tester la capacité de l'algorithme d'imagerie proposé pour localiser différents objets enfouis. Les résultats encourageants montrent que cet algorithme est capable d'estimer la position de différents objets enfouis et pas uniquement les armatures avec une erreur d'estimation de (0-1) mm. Les performances de l'algorithme ont été comparées à celles d'une méthode de migration et aux résultats de mesure obtenus avec un pachomètre. Ces comparaisons ont systématiquement révélé une meilleure précision de la localisation avec l'algorithme développé.Une autre étude a été proposée dans ce travail en testant l'algorithme avec des signaux réels modifiés. Ces signaux sont produits en réduisant le gain le moins possible. La conclusion la plus évidente de cette étude est que l'algorithme proposé est capable de localiser les différents objets même si les signaux réfléchis par eux sont de faible amplitudeLack of acquaintance in the real geometry of a structure leads to incorrect evaluation of its state. Consequently, this will lead to inaccurate estimation of bearing capacity, durability, stability and moreover, the need for repair or strengthening. Furthermore, optimization of the required time for repair process needs to well recognize the parts of structure to be assessed and also to avoid the critical zones such as reinforcing bars, cables, etc., during repairing. Therefore; it becomes necessary to use a non-destructive testing (NDT) method in order to know the real geometry of structure in particular, the location of reinforcements in reinforced concrete structures. GPR is considered as an ideal non-invasive technique in detecting and locating these reinforcements. However, its accuracy in localization is limited. The aim of this research project has therefore been to increase the accuracy of GPR in recognizing the internal geometry of reinforced concrete structures. The main objective of this study is to locate accurately the position of reinforcements into three dimensions. To achieve this purpose, a new methodology for GPR measurement and processing is proposed in this study.Several configurations of data acquisition using simulated signals are tested to propose and develop an appropriate imaging algorithm for the propagation medium to imagine its internal geometry and to locate accurately the reinforcing bars. Further processing are applied to improve the accuracy of detection and to identify the different interfaces in the tested medium. Both algorithm and processing are applied on simulated signals. Subsequent experimental validations have been applied using real signals acquired from different real reinforced concrete slabs. The goal is to test the ability of proposed imaging algorithm for the localization of different targets. The encouraging results indicate that this algorithm is able to estimate the position of different buried targets and not only the reinforcing bars with an estimation error of (0-1)mm.The performance of proposed algorithm has compared to those of migration method and to the results obtained from pachometer. These comparisons have systematically revealed a better localization accuracy using the developed algorithm.Another study has been proposed in this work by testing the algorithm using modified real signals. These signals are produced by reducing the gain as less as possible. The most obvious finding to emerge from this study is that the proposed algorithm is able to localize the different goals even if the signals reflected by them are of low amplitude
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Gärdsback, Mattias. "Deployment Control of Spinning Space Webs and Membranes." Doctoral thesis, KTH, Strukturmekanik, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9574.
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Future solar sail and solar power satellite missions require deployment of large and lightweight flexible structures in space. One option is to spin the assembly and use the centrifugal force for deployment, stiffening and stabilization. Some of the main advantages with spin deployment are that the significant forces are in the plane of rotation, a relatively simple control can be used and the tension in the membrane or web can be adjusted by the spin rate to meet the mission requirements. However, a successful deployment requires careful development of new control schemes. The deployment rate can be controlled by a torque, applied either to a satellite in the center or by thrusters in the corners, or by deployment rate control, obtained by tether, spool braking or folding properties. Analytical models with only three degrees of freedom were here used to model the deployment of webs and membranes for various folding patterns and control schemes, with focus on space webs folded in star-like arms coiled around a center hub. The model was used to investigate control requirements and folding patterns and to obtain optimal control laws for centrifugal deployment. New control laws were derived from the optimal control results and previously presented control strategies. Analytical and finite element simulations indicate that the here developed control laws yield less oscillations, and most likely more robustness, than existing controls. Rotation-free (RF) shell elements can be used to model inflation or centrifugal deployment of flexible memebrane structures by the finite element method. RF elements approximate the rotational degrees of freedom from the out-of-plane displacements of a patch of elements, and thus avoid common singularity problems for very thin shells. The performance of RF shell elements on unstructured grids is investigated in the last article of this thesis, and it is shown that a combination of existing RF elements performs well even for unstructured grids.QC 20100729
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Degryse, Emmanuel. "Etude d'une nouvelle approche pour la conception de capteurs et d'actionneurs pour le contrôle des systèmes flexibles." Compiègne, 2001. http://www.theses.fr/2001COMP1363.
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Dans le domaine du contrôle actif des structures flexibles, l'efficacité de la loi de commande dépend beaucoup du positionnement des capteurs et des actionneurs. Dans ce travail, nous présentons un nouveau critère de positionnement de capteurs et d'actionneurs non colocalisés : celui-ci consiste à assurer que le système "structure flexible/actionneurs/capteurs" se comporte comme un système positif réel dans le domaine des basses fréquences. Le contrôle d'une plaque, munie d'un actionneur ponctuel fixe et de capteurs piézo-électriques, est d'abord étudié. Nous pouvons alors formuler notre critère comme un problème d'optimisation topologique dans la mesure où la position et la topologie des capteurs sont inconnus a priori, Des résultats théoriques essentiels pour ce problème sont montrés et nous présentons des résultats numériques. Notre méthode est ensuite étendue au cas où les capteurs et les actionneurs, tous deux piézo-électriques, sont optimisés simultanément, La dernière partie de ce travail est consacrée à la stabilisation du système. Plusieurs lois de commande ont été mises en oeuvre et les résultats numériques montrent que notre système peut être stabilisé de manière satisfaisante par des contrôleurs d'ordre peu élevé.
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Anderson, Ricky D. "A parts classification and coding system utilizing functional and shape characteristics in a matrix-code structure." Ohio : Ohio University, 1992. http://www.ohiolink.edu/etd/view.cgi?ohiou1171483811.
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Frost, Elizabeth Marie. "Creating a Well-Situated Human-Autonomy Team: The Effects of Team Structure." Wright State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=wright1578914702378707.
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Papučík, Lukáš. "Stavebně technologický projekt pro Polyfunkční komplex Rudiny II. - Žilina, objekt Blok D." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409938.
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The aim of the thesis is to solve selected parts of the construction technology project for the building of the multifunctional complex Rudiny II, Žilina - building block D. The content of the thesis is a technical report to the construction technology project, studies of the implementation of the main technological stages of the building. technological regulation for horizontal and vertical monolithic structures, quality control and testing plan for the production of vertical and horizontal monolithic structures, OSH plan. In the appendix of my diploma thesis I processed drawings of construction equipment, itemized budget of the building, object budget according to THU, time plan of construction, dimensions of construction machines, laying plan for system formwork on standardized floor of multifunctional house.
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Le, Jeune Léonard. "Imagerie ultrasonore par émission d'ondes planes pour le contrôle de structures complexes en immersion." Sorbonne Paris Cité, 2016. http://www.theses.fr/2016USPCC015.
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Cette thèse, réalisée dans le cadre du contrôle non-destructif par ultrasons, propose deux nouvelles méthodes adaptatives visant à imager en temps réel des structures de surfaces complexes et irrégulières. Ces méthodes ont été développées pour les contrôles en immersion (sans contact) où l'eau assure la transmission des ultrasons dans le solide. Le principe général de l'imagerie adaptative par ultrasons est de mesurer acoustiquement la surface située sous le capteur, puis de déterminer les trajets ultrasonores à travers la surface mesurée pour réaliser une image dans le matériau. Une des méthodes pouvant être appliquée en mode adaptatif est la méthode Synthetic Transmit Aperture (STA). Elle fournit des images de grande qualité et offre la possibilité d'utiliser différents modes de reconstruction pour améliorer la caractérisation des défauts, en fonction de leur géométrie et de leur orientation. Cependant, elle présente deux inconvénients majeurs : un grand volume de données à stocker et à traiter pour calculer une image, et une plus grande sensibilité au bruit électronique ou de structure que les méthodes échographiques conventionnelles. Pour pallier ces inconvénients, la méthode Plane Wave Imaging (PWI), basée sur l'émission d'ondes planes, est proposée. Les résultats obtenus pour des surfaces planes montrent que les deux méthodes fournissent des résultats comparables en termes de résolution spatiale mais l'imagerie par émission d'ondes planes est plus robuste en présence de bruit incohérent. Ils montrent aussi que la méthode PWI améliore nettement la qualité des images dans le cas de fissures, et qu'un très faible nombre de transmissions est nécessaire par rapport à la méthode STA. Les méthodes STA et PWI ont ensuite été généralisées pour traiter le cas d'une surface complexe, et couplées à des méthodes de mesure de surface pour réaliser de l'imagerie adaptative. Les deux méthodes donnent les mêmes images que celles obtenues lorsque tous les paramètres de contrôle sont connus et la méthode PWI adaptative conserve les avantages présentés précédemment : faible sensibilité au bruit et nombre réduit de transmissionsThis thesis, made in the non-destructive testing field, presents two new adaptive methods, looking for real-time imaging of structures with complex and irregular surfaces. These methods have been developed for immersion testing (contactless) where water ensure the transmission of the ultrasonic waves in the solid. The general principle of adaptive imaging is to acoustically measure the surface under the probe, then to determine the ultrasonic paths through the complex surface to produce an image inside the material. One of the methods that can be applied to adaptive imaging is the Synthetic Transmit Aperture (STA) method. It provides high quality images and offers the possibility of using different reconstruction modes to improve the defect charaterization, depending on their geometry and orientation. However, it suffers from two major drawbacks: a large amount of data to be stored and processed, and a higher sensibility to random or structural noise than the conventional imaging methods. To overcome these drawbacks, we propose the PlaneWave Imaging (PWI) method, based on plane wave transmissions. The results on a plane surface show that the two methods give similar results in terms of spatial resolution, but PWI is less sensitive to random noise. They also reveal that PWI improves greatly image quality when defects are cracks, and that very few transmissions are needed compared to STA. The STA and PWI methods are then generalized to complex surfaces, and coupled with surface measurement methods to perform adaptive imaging. The two méthods give the same images that those obtained when all the control parameters are known and the adaptive PWI keeps the advantages introduced previously : low sensibility to random noise and reduced number of transmission
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Crano, Ricky D'Andrea. "Posthuman Capital: Neoliberalism, Telematics, and the Project of Self-Control." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1405531247.
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Lemartinel, Antoine. "Development of self-sensing structural composites parts for wind mill blades monitoring." Thesis, Lorient, 2017. http://www.theses.fr/2017LORIS466.
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La demande croissante d’électricité, notamment renouvelable, entraîne une croissance de l’éolien avec l’utilisation de pales en composite de plus en plus grandes. Pour réduire le cout de maintenance de ces structures composites, le suivi de santé structurel (SHM) au cours du temps permet d’évaluer le comportement de la structure, d’anticiper les dégradations et la maintenance. Dans ce cadre, le développement de capteurs, à base de résine époxy et de nanotubes de carbone, appelés Quantum Resistive Sensor (QRS), est présenté. Les QRS peuvent être attachés à la surface de la structure ou intégrés à cœur durant la séquence de drapage. Durant la polymérisation de la résine, le comportement électrique du QRS traduit l’évolution de la réticulation et de la température dans la structure. Suite au processus de fabrication, l’influence des paramètres extérieurs (température, humidité, vitesse de déformation, coefficient de Poisson…) sur les caractéristiques des QRS a été étudiée. Durant l’utilisation de la structure composite, les QRS ont également permis la détection et la propagation d’endommagements jusqu’à la fracture ultime. Les QRS représentent donc une solution potentielle comme capteurs SHM non intrusifs, permettant un suivi de la structure, de sa fabrication jusqu’à sa dégradation finaleThe growing demands for electrical energy, especially renewable, is boosting the development of wind turbines equipped with longer composite blades. To reduce the maintenance cost of such huge composite parts, the structural health monitoring (SHM) is an approach to anticipate and/or follow the structural behaviour along time. To do so, a proper instrumentation is necessary and has to be as less intrusive as possible. To this end, the development of carbon nanotube- epoxy Quantum Resistive Sensor (QRS) is presented. QRS can be as well glued on the surface or embedded in the core of the composite structure during the stacking sequence. During manufacturing, both the temperature and resin crosslinking can be detected with the change in the QRS electrical characteristics. Once the structural part is made, the effect of the external parameters (strain rate, temperature, humidity, Poisson ratio…) on the electrical characteristics of QRS has been studied. During the composite life, the QRS electrical behaviour has also demonstrate its capability to detect the initiation and propagation of damage until final failure. A non-intrusive monitoring with QRS of the structure life cycle, from manufacturing until final breakage is therefore possible
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Lasne, Agnès. "Structures electriques de controle de l'alignement dans les procedes de fabrication des circuits integres : application a la qualification d'equipement de lithographie avancee." Toulouse, INSA, 1987. http://www.theses.fr/1987ISAT0021.
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Sudibyo, Harry. "Une methode de test des circuits integres vlsi a structure pipeline serie et la generation automatique des vecteurs de test." Paris 6, 1987. http://www.theses.fr/1987PA066633.
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Le generateur automatique de vecteurs de test genevec qui est presente dans cette these, genere les vecteurs de test destines au test exhaustif du circuit integre vlsi dont la conception est faite a l'aide des cellules precaracterisees. Un fichier de description du test du circuit est forme d'un ensemble de donnees logiques d'interconnexions entre les blocs de base extraites a partir de la description "a plat" du circuit a tester et de donnees fonctionnelles sur les blocs de base qui constituent le circuit. La generation des vecteurs de test est effectuee d'apres ces informations. Cette etude s'applique aux circuits integres a structure pipeline serie. Ces circuits sont concus a l'aide d'une bibliotheque de cellules cmos, en utilisant les outils de la chaine de conception assistee par ordinateur emilie. La chaine de cao etablit la continuite des servitudes et des chemins de test. La methode que nous presentons dans ce travail est basee sur le test exhaustif du circuit en utilisant les chemins de test et en appliquant la methode lssd. Le but final est d'arriver a tester toute la partie combinatoire de chaque cellule standard, c'est a dire approcher taux de couverture 100%
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Troudi, Rami. "Étude, conception et structure de commande temps réel d'un onduleur multiniveau à partir d'une seule source DC ; applications énergies renouvelables et véhicules électriques." Thesis, Poitiers, 2021. http://www.theses.fr/2021POIT2262.
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Les travaux de recherche de la thèse de Rami Troudi répondent à trois problématiques :-la première est de concevoir un onduleur triphasé multiniveau pour des applications à base d’énergies renouvelables connectées au réseau de distribution, ou pour la motorisation des véhicules électriques. Dans la première application, l’utilisation de bras multiniveau limite fortement les inductances de couplage avec le réseau tandis que dans la deuxième application, le couple délivré par le moteur est de meilleure qualité.-la deuxième consiste à concevoir une structure de convertisseur DC-DC permettant de n’avoir qu’une seule source continue pour alimenter cet onduleur multiniveau. -la troisième est la conception d’une architecture de commande temps réel à base de microcontrôleurs permettant d’avoir une grande capacité d’évolution et de calcul et une facilité d’industrialisation.Le manuscrit de la thèse est organisé en quatre chapitres. Le premier chapitre présente un état de l’art des structures d’onduleur multiniveau. Cette technologie est devenue aujourd’hui un thème de recherche important. Ce chapitre donne les avantages et les inconvénients de chaque topologie d’onduleur multiniveau conventionnel ainsi que les nouvelles topologies permettant une réduction du nombre de composants. Ce chapitre fait aussi un état de l’art des structures de hacheurs avec une ou plusieurs entrées-sorties (MISO, MIMO et SIMO). Ce chapitre présente aussi les avantages et les inconvénients de chaque famille de structure avec leur commande. La fin du chapitre présente les nouvelles topologies retenues pour l’onduleur multiniveau et le hacheur SIQO (une entrée-quatre sorties).Le deuxième chapitre est consacré à la présentation de la structure de l’onduleur multiniveau proposé, ainsi qu’à l’étude de son mode de fonctionnement, de sa commande rapprochée et de son utilisation dans une application en boucle fermée. Ce chapitre montre que cette structure a l’avantage de minimiser les pertes dans les composants de puissance en ayant, à chaque instant, peu de composants qui conduisent le courant de chaque bras, ce qui permet d’augmenter son rendement. En plus, ce chapitre montre la simplicité de la commande rapprochée de l’onduleur en utilisant un algorithme très simple. Des essais expérimentaux sont donnés à la fin du chapitre après le descriptif de la maquette d’essai.Le troisième chapitre traite en détail la structure du convertisseur DC-DC SIQO utilisé pour alimenter l’onduleur multiniveau, son mode de fonctionnement, sa modélisation et le développement d’une commande multi-entrée multi-sortie (MIMO). Cette structure est conçue à partir d’un couplage de la structure SEPIC avec la structure à accumulation magnétique et du dédoublement de chaque sortie par un système d’aiguillage qui permet ainsi d’obtenir quatre sorties à partir d’une seule entrée DC. Chaque structure (SEPIC et à accumulation) gère deux sorties avec le calcul de deux rapports cycliques. Pour cela, une synthèse d’asservissement basée sur une méthode H_∞ est présentée pour être robuste aux variations des courants et aux changements de consigne. Les résultats des essais expérimentaux sont donnés à la fin du chapitre après le descriptif de la maquette d’essai.Le chapitre quatre aborde le développement de l’architecture de commande à base de microcontrôleurs. Cette structure est appliquée au contrôle de l’onduleur triphasé. Ce chapitre décrit toutes les fonctions qui composent cette architecture au niveau matériel et logiciel. Le fait de répartir les besoins matériels et algorithmiques sur plusieurs microcontrôleurs permet de faciliter l’évolution des demandes de fonctions supplémentaires à savoir le diagnostic et la reconfiguration d’un bras, ainsi que l’ajout de la fonction de filtrage actif. Cette architecture repose sur une communication par bus SPI (Serial Peripheral Interface) qui permet des échanges rapides entre les microcontrôleurs et aussi vers un système IHM (Interface Homme Machine)Rami Troudi's thesis research work addresses three problematics:- the first is to design a three-phase multilevel inverter for applications based on renewable energies connected to the power grid, or for electric motor drive of electric vehicles. In the first application, the use of multilevel arms greatly limit the coupling inductances with the power grid, while in the second application, the torque delivered by the motor is of better quality.- the second is to design a DC-DC converter structure having only one DC source destinated to supply this multilevel inverter.- the third is the design of a real-time control architecture based on microcontrollers leading to a large capacity of evolution and calculation and an ease industrialization.The thesis manuscript is organized into four chapters.The first chapter presents a state of art of multilevel inverter structures. This technology is becoming an important research topic today. This chapter gives the advantages and disadvantages of each conventional multilevel inverter topology as well as the new topologies with a reduction in the number of components. This chapter also give a reviews of the state of art of chopper structures with one or multiple inputs-outputs (MISO, MIMO and SIMO). This chapter also presents the advantages and the disadvantages of each family of structure with their regulation. The end of the chapter presents the new topologies retained for the multilevel inverter and the SIQO chopper (one input-four outputs).The second chapter is devoted to the presentation of the structure of the proposed multilevel inverter, as well as to the study of its mode of operation, its close control device and its use in a closed loop application. This chapter shows that this structure has the advantage of minimizing losses in power components by having, at any time, few components that conduct the current of each arm, which allows to increase its efficiency. In addition, this chapter shows the simplicity of the used close control of the inverter employing a very simple algorithm. Experimental tests are given at the end of the chapter after the description of the test bed.The third chapter discusses in detail the structure of the SIQO DC-DC converter used to supply the multilevel inverter, its operation mode, its modeling and the development of a multi-input multi-output (MIMO) control. This structure is designed from a coupling of the SEPIC structure with the buck-boost structure and the doubling of each output by a switching system which leads to obtain four outputs from a single DC input. Each structure (SEPIC and buck-boost) manages two outputs with the calculation of two duty cycles. For this, a control synthesis based on an Hinfini method is presented to be robust to the variations of the currents and the changes of the setpoint. The results of the experimental tests are given at the end of the chapter after the description of the test bed.Chapter four discusses the development of one architecture based on multi-microcontroller system. This structure is applied to the control of the three-phase multilevel inverter. This chapter describes all the functions that compose this architecture at the hardware and software level. The distribution of the hardware and algorithmic needs several microcontrollers makes it easier to evolve the demands for additional functions, namely the diagnosis and reconfiguration of an arm, as well as the addition of the active filtering function. This architecture is based on SPI (Serial Peripheral Interface) bus communication which allows rapid exchanges between the microcontrollers and also towards an HMI (human-machine interfaces) system
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Galindo, Muñoz Natalia. "Development of direct measurement techniques for the in-situ internal alignment of accelerating structures." Doctoral thesis, Universitat Politècnica de València, 2018. http://hdl.handle.net/10251/100488.
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Las exigentes tolerancias de alineación en los componentes de los futuros colisionadores lineales de partículas requieren el desarrollo de nuevas técnicas de alineación más precisas que las existentes. Este es el caso del Colisionador Lineal Compacto (Compact Linear Collider, CLIC), cuyos objetivos altamente restrictivos de alineamiento alcanzan los 10 um. Para poder lograr el máximo rendimiento del acelerador, es necesario que el posicionamiento de las estructuras que aceleran las partículas y de los campos que las guían cumplan las tolerancias de alineación para dirigir el haz a lo largo de la trayectoria diseñada. Dicho procedimiento consiste en relacionar la posición de los ejes de referencia de cada componente con respecto a objetos externos, o fiduciales, lo cual resulta muy tedioso y económicamente costoso. Los errores sistemáticos y aleatorios se van acumulando en cada paso del proceso y, en consecuencia, la precisión final de alineamiento es todo un desafío. En este contexto, nace el proyecto PACMAN (Particle Accelerator Components Metrology and Alignment to the Nanometre scale), subvencionado por la Unión Europea en el programa FP7 de financiación para la investigación e innovación. El objetivo principal de PACMAN es investigar, desarrollar e implementar una solución integrada alternativa que incorpore todos los pasos de alineación en una misma ubicación, con el objetivo de mejorar la precisión de alineación de los componentes de los aceleradores, en concreto: las estructuras aceleradoras, los cuadrupolos y los monitores de posición de haz. La viabilidad de las soluciones desarrolladas y la precisión de alineamiento alcanzada deben de demostrarse en un banco de pruebas utilizando componentes de CLIC. La estrategia de PACMAN para alcanzar el objetivo técnico se divide en tres pasos. El primero consiste en la fiducialización de los componentes y sus soportes. El segundo paso es el ensamblaje de los componentes en dos tipos de soporte, uno compuesto por un monitor de posición de haz y un cuadrupolo, y otro con cuatro estructuras aceleradoras, tomando como referencia su centro electromagnético. Finalmente, ambos soportes se transportan al túnel para su alineación final utilizando técnicas de hilos tensados. En esta tesis doctoral, se describe el desarrollo de una nueva técnica no destructiva para localizar los ejes electromagnéticos de estructuras aceleradoras y su validación experimental. Para ello, se ha utilizado una estructura aceleradora de CLIC conocida como TD24. Debido a la complejidad mecánica de la TD24, su difícil acceso y su diámetro medio de iris de 5.5 mm, se desarrolla una nueva técnica denominada en esta tesis como 'el método perturbativo' y se realiza una propuesta experimental de validación. El estudio de viabilidad de este método, cumpliendo con los requisitos impuestos de precisión en la medida de 10 um, ha sido realizado con una campaña extensa de simulaciones de campos electromagnéticos en tres dimensiones utilizando la herramienta de software conocida como HFSS. Los resultados de simulación han permitido el desarrollo de un algoritmo muy completo de medidas y han proporcionado las especificaciones técnicas para el diseño conceptual de un banco de pruebas para la medida de los ejes electromagnéticos de la TD24. El preciso ensamblaje del banco de pruebas y sus correspondientes calibraciones, la incorporación de nuevos tratamientos de las medidas en el algoritmo final y la caracterización de fuentes de error en la medida, favorecieron la localización del centro electromagnético en la TD24 con una precisión menor a 1 um con un error estimado menor que 8.5 um, cumplimiendo con los objetivos de precisión establecidos.In the next generation of linear particle accelerators, challenging alignment tolerances are required in the positioning of the components focusing, accelerating and detecting the beam over the accelerator length in order to achieve the maximum machine performance. In the case of the Compact Linear Collider (CLIC), accelerating structures, beam position monitors and quadrupole magnets need to be aligned in their support with respect to their reference axes with an accuracy of 10 um. To reach such objective, the PACMAN (Particle Accelerator Components Metrology and Alignment to the Nanometer Scale) project strives for the improvement of the current alignment accuracy by developing new methods and tools, whose feasibility should be validated using the major CLIC components. This Ph.D. thesis concerns the investigation, development and implementation of a new non-destructive intracavity technique, referenced here as 'the perturbative method', to determine the electromagnetic axes of accelerating structures by means of a stretched wire, acting as a reference of alignment. Of particular importance is the experimental validation of the method through the 5.5 mm iris-mean aperture CLIC prototype known as TD24, with complex mechanical features and difficult accessibility, in a dedicated test bench. In the first chapter of this thesis, the alignment techniques in particle accelerators and the novel proposals to be implemented in the future linear colliders are introduced, and a detailed description of the PACMAN project is provided. The feasibility study of the method, carried out with extensive electromagnetic fields simulations, is described in chapter 2, giving as a result, the knowledge of the theoretical accuracy expected in the measurement of the electromagnetic axes and facilitating the development of a measurement algorithm. The conceptual design, manufacturing and calibration of the automated experimental set-up, integrating the solution developed to measure the electromagnetic axes of the TD24, are covered in chapter 3. The future lines of research and developments of the perturbative method are also explored. In chapter 4, the most significant results obtained from an extensive experimental work are presented, analysed and compared with simulations. The proof-of-principle is completed, the measurement algorithm is optimised and the electromagnetic centre is measured in the TD24 with a precision less than 1 um and an estimated error less than 8.5 um. Finally, in chapter 5, the developments undertaken along this research work are summarised, the innovative achievements accomplished within the PACMAN project are listed and its impact is analysed.
En la generació pròxima d'acceleradors de partícules lineals, desafiant toleràncies d'alineament és requerit en el posicionament dels components que enfoquen, accelerant i detectant la biga sobre la longitud d'accelerador per tal d'aconseguir l'actuació de màquina màxima. En el cas del Colisionador Compacte Lineal (CLIC), accelerant estructures, monitors de posició de fes i imants necessiten ser alineats en el seu suport amb respectar a les seves destrals de referència amb una precisió de 10 um. Per assolir tal objectiu, el PACMAN (Metrologia de Components de l'Accelerador de partícules i Alineament al Nanometer Escala) projecte s'esforça per la millora de l'actual precisió d'alineament per mètodes nous en desenvolupament i eines, la viabilitat dels quals hauria de ser validada utilitzant els components de CLIC importants. Aquesta tesi concerneix la investigació, desenvolupament i implementació d'un nou no-destructiu tècnica interna, va referenciar ací mentre 'el mètode de pertorbació' per determinar les destrals electromagnètiques d'accelerar estructures mitjançant un cable estès, actuant com a referència d'alineament. De la importància particular és la validació experimental del mètode a través del 5.5 mm iris-roí obertura prototipus de CLIC sabut com TD24, amb característiques mecàniques complexes i accessibilitat difícil, en un banc de prova dedicat. En el primer capítol d'aquesta tesi, les tècniques d'alineament en acceleradors de partícules i les propostes novelles per ser implementades en el futur colisionador lineal és introduït, i una descripció detallada del projecte PACMAN és proporcionat. L'estudi de viabilitat el mètode de pertorbació, va dur a terme amb simulacres de camps electromagnètics extensos, és descrit dins capitol 2, donant com a resultat, el coneixement de la precisió teòrica esperada en la mida de les destrals electromagnètiques i facilitant el desenvolupament d'un algoritme de mida. El disseny conceptual, fabricació i calibratge del conjunt experimental automatitzat-amunt, integrant la solució desenvolupada per mesurar les destrals electromagnètiques del TD24, és cobert dins capitol 3. Les línies futures de recerca i desenvolupaments del mètode és també va explorar. Dins capitol 4, la majoria de resultats significatius van obtenir d'una faena experimental extensa és presentada, analitzat i comparat amb simulacres. La prova-de-el principi és completat, l'algoritme de mida és optimitzat i el centre electromagnètic és mesurat en el TD24 amb una precisió menys d'1 um i un error calculat menys de 8.5 um. Finalment, dins capitol 5, els desenvolupaments empresos al llarg d'aquesta faena de recerca és resumit, les consecucions innovadores van acomplir dins del projecte PACMAN és llistat i el seu impacte és analitzat.
Galindo Muñoz, N. (2018). Development of direct measurement techniques for the in-situ internal alignment of accelerating structures [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/100488
TESIS
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Mountassir, Mahjoub El. "Surveillance d'intégrité des structures par apprentissage statistique : application aux structures tubulaires." Thesis, Université de Lorraine, 2019. http://www.theses.fr/2019LORR0047.
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Les approches de surveillance de l’intégrité des structures ont été proposées pour permettre un contrôle continu de l’état des structures en intégrant à celle-ci des capteurs intelligents. En effet, ce contrôle continu doit être effectué pour s’assurer du bon fonctionnement de celles-ci car la présence d’un défaut dans la structure peut aboutir à un accident catastrophique. Cependant, la variation des conditions environnementales et opérationnelles (CEO) dans lesquelles la structure évolue, impacte sévèrement les signaux collectés ce qui induit parfois une mauvaise interprétation de la présence du défaut dans la structure. Dans ce travail de thèse, l’application des méthodes d’apprentissage statistiques classiques a été envisagée dans le cas des structures tubulaires. Ici, les effets des paramètres de mesures sur la robustesse de ces méthodes ont été investiguées. Ensuite, deux approches ont été proposées pour remédier aux effets des CEO. La première approche suppose que la base de données des signaux de référence est suffisamment riche en variation des CEO. Dans ce cas, une estimation parcimonieuse du signal mesuré est calculée. Puis, l’erreur d’estimation est utilisée comme indicateur de défaut. Tandis que la deuxième approche est utilisée dans le cas où la base de données des signaux des références contient une variation limitée des CEO mais on suppose que celles-ci varient lentement. Dans ce cas, une mise à jour du modèle de l’état sain est effectuée en appliquant l’analyse en composante principale (PCA) par fenêtre mobile. Dans les deux approches, la localisation du défaut a été assurée en utilisant une fenêtre glissante sur le signal provenant de l’état endommagéTo ensure better working conditions of civil and engineering structures, inspections must be made on a regular basis. However, these inspections could be labor-intensive and cost-consuming. In this context, structural health monitoring (SHM) systems using permanently attached transducers were proposed to ensure continuous damage diagnostic of these structures. In SHM, damage detection is generally based on comparison between the healthy state signals and the current signals. Nevertheless, the environmental and operational conditions will have an effect on the healthy state signals. If these effects are not taken into account they would result in false indication of damage (false alarm). In this thesis, classical machine learning methods used for damage detection have been applied in the case of pipelines. The effects of some measurements parameters on the robustness of these methods have been investigated. Afterthat, two approaches were proposed for damage diagnostic depending on the database of reference signals. If this database contains large variation of these EOCs, a sparse estimation of the current signal is calculated. Then, the estimation error is used as an indication of the presence of damage. Otherwise, if this database is acquired at limited range of EOCs, moving window PCA can be applied to update the model of the healthy state provided that the EOCs show slow and continuous variation. In both approaches, damage localization was ensured using a sliding window over the damaged pipe signal
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Bossens, Frédéric. "Amortissement actif des structures câblées: de la théorie à l'implémentation." Doctoral thesis, Universite Libre de Bruxelles, 2001. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/211598.
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Cette thèse s'inscrit dans la continuation du travail de Younes Achkire, consacré au contrôle actif des ponts haubanés. Elle traite de l'implémentation d'un système de contrôle actif sur des maquettes de structures câblées. Deux types de structures sont étudiés expérimentalement: les ponts haubanés et les treillis spatiaux. Après une brève introduction sur l'usage du contrôle actif dans ces domaines, le chapitre 2 traite numériquement des mécanismes d'interaction entre le câble et la structure. Au chapitre 3, nous présentons la stratégie de contrôle que nous utilisons pour stabiliser une structure câblée: il s'agit d'un contrôle décentralisé, basé sur des paires capteur/actionneur colocalisées, placées au niveau des ancrages des câbles, chacune équipée d'un contrôleur Intégral Force Feedback. Nous présentons une théorie linéaire simplifiée permettant de dimensionner le système et de prévoir son efficacité. Elle est illustrée sur un exemple, et nous discutons de la validité de certaines hypothèses simplificatrices. Le chapitre 4 est consacré au contrôle actif des ponts haubanés. Nous y présentons 2 maquettes. La première, de petite taille (3m) représente un pylône de pont haubané en construction. Elle est équipée d'actionneurs piézoélectriques. La seconde, installée au Centre Commun de Recherche d'Ispra (Italie), mesure 30m de long, et est équipée d'actionneurs hydrauliques. Les expériences réalisées sur ces maquettes ont démontré l'efficacité du contrôle et la fiabilité de la théorie prédictive. Le contrôle du flottement des ponts est traité sur un exemple numérique. Le chapitre 5 relate nos expériences d'amortissement actif des treillis spatiaux. Deux structures ont été étudiées: une colonne en treillis équipée de 3 câbles actifs, et une structure triédrique suspendue à des cordons élastiques pour simuler l'absence de gravité, également munie de câbles actifs. Deux concepts d'actionneur piézoélectrique ont été testés. Nous avons ensuite examiné le problème de la saturation des actionneurs, et celui du contrôle actif des microvibrations (~10nm) d'une structure câblée. Le chapitre 6 conclut ce travail, en souligne les aspects originaux et donne quelques perspectives de développement.Doctorat en sciences appliquées
info:eu-repo/semantics/nonPublished
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Fereyre, Florian. "LA PLACE D'UNE TECHNOLOGIE D'INFORMATION ET DE COMMUNICATION DANS LE PROCESSUS DE STRUCTURATION D'UNE ORGANISATION : Le cas de l'usage d'une messagerie électronique." Phd thesis, Université Jean Moulin - Lyon III, 2010. http://tel.archives-ouvertes.fr/tel-00552291.
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Ce travail de recherche tente d'appréhender la place occupée par une technologie d'information et de communication (TIC) au sein de la théorie de la structuration, développée par Anthony Giddens. Nous avons, dans ce cadre, étudié l'usage d'une messagerie électronique interne Lotus Notes au sein d'une organisation commune à EDF et Gaz de France. Ce travail est fondé sur une analyse de l'usage de cette TIC dans un cadre professionnel, sur l'examen de ses formes de déterminations et sur la caractérisation des logiques dans lesquelles elle s'intègre. Ces phénomènes sont liés aux usages de la messagerie en tant que ressource d'allocation et support pour les ressources d'autorité. Ces activités s'inscrivent dans le processus de contrôle réflexif de l'action des usagers. L'étude de ces phénomènes nous a permis de mettre en évidence l'importance de la messagerie électronique en tant que conteneur d'information, participant à la cueillette, à l'entreposage et au recouvrement d'information, ainsi que la place de ces activités dans le processus de structuration à l'œuvre dans l'organisation considérée. Ces phénomènes traduisent un principe structurel fondé sur le contrôle des échanges et de l'information.
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Zaiter, Rayan. "Silver and/or mercury doped thioarsenate and thiogermanate glasses : Transport, structure and ionic sensibility." Thesis, Littoral, 2018. http://www.theses.fr/2018DUNK0485/document.
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Le but de ce travail de thèse consiste à étudier les propriétés physico-chimiques des verres chalcogénures afin de pouvoir les utiliser comme membranes de capteurs chimiques destinés pour le dosage des ions Hg²⁺. Dans un premier temps, les propriétés macroscopiques des systèmes vitreux AgY-As₂S₃ (Y = Br, I), HgS-GeS₂, AgI-HgS-As₂S₃ et AgI-HgS-GeS₂, telles que les densités et les températures caractéristiques (Tg et Tc) ont été mesurées et analysées selon les compositions des verres. Puis, dans un second temps, les propriétés de transport ont été étudiés à l'aide de la spectroscopie d'impédance complexe d'une part, ou d'autre part, par des mesures de la résistivité. Ces dernières montrent que les verres de chalcogénures dopés à l'halogénure d'argent présentent deux différents régimes de transports au-dessus du seuil de percolation xc ≈ 30 ppm : (i) domaine de percolation critique, et (ii) domaine contrôlé par modificateur. Vient ensuite la troisième partie, elle consiste à déchiffrer les relations composition/structure/propriété grâce à plusieurs études structurales. Des mesures par spectroscopie Raman, par diffraction de neutrons et de rayons X haute énergie, par diffusion des neutrons sous petits angles (SANS), ainsi que des modélisations RMC/DFT et AMID ont été réalisées. Enfin, la dernière partie de ce travail était une étude préliminaire des caractéristiques des nouveaux capteurs chimiques. Il a été consacré à l'étude des relations entre la composition et la sensibilité des membranes ainsi qu'aux limites de détection qui les définissentThe aim of the thesis is to study the physicochemical properties of the silver halide doped chalcogenide glasses for the possibility to use them as chemical sensors for quantitative analysis of Hg²⁺ ions. First, the macroscopic properties of AgY-As₂S₃ (Y = Br, I), HgS-GeS₂, AgI-HgS-As₂S₃ and AgI-HgS-GeS₂ glassy systems such as the densities and the characteristic temperatures (Tg and Tc) were measured and analyzed according to the glass compositions. Second, the transport properties were studied using complex impedance and dc conductivity. Measurements show that the silver halide doped chalcogenide glasses exhibit two drastically different ion transport regimes above the percolation threshold at xc ≈ 30 ppm : (i) critical percolation, and (ii) modifier-controlled regimes. Third, to unveil the composition/structure/property relationships, various structural studies were carried out. Raman spectroscopy, high-energy X-ray diffraction, neutron diffraction and small-angle neutron scattering experiments, together with RMC/DFT and AMID modelling were employed. Finally, the last part was a preliminary study of the characteristics of new chemical sensors. It was devoted to study the relationship between the membranes' composition and sensitivity but also detection limits
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Abbadi, Amal. "Développement des réseaux de capteurs sans fil noyés dans le béton pour la surveillance des ouvrages de génie civil." Thesis, Lille 1, 2015. http://www.theses.fr/2015LIL10195/document.
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L’objectif de ce mémoire de thèse est de mener des recherches sur l’utilisation des technologies sans contact pour la surveillance de santé structurale. Les recherches comportent des développements scientifiques et technologiques visant à bien comprendre le fonctionnement des réseaux de capteurs sans fils dans un milieu hétérogène. Tout d’abord, nos études se concentrent sur les mesures des coefficients de réflexion et de transmission des ondes électromagnétiques dans le béton. La réalisation d’une communication entre deux antennes patch noyées dans du béton a permis de confirmer l’effet de l’humidité du béton sur l’atténuation des ondes radio dans le béton. Cette analyse a conduit à l'identification des propriétés diélectriques du béton pour la fréquence 860 MHz. Ensuite, nous avons étudié l’influence des configurations des armatures du béton (emplacement des armatures, dimensions des armatures) sur les coefficients de réflexion et de transmission. Nous avons étudié et optimisé une topologie de réseaux de capteurs sans fils adéquate pour être noyée dans le béton armé. L’étude d’optimisation prend en compte les caractéristiques des nœuds de capteurs, le bilan de liaison entre un nœud de capteur communicant et le puits et la durée de vie d’un nœud. Enfin, la conception et la réalisation d’un « totem en béton armé » d’une hauteur de 3 m, a permis de valider les différentes études abordées au cours de ces travaux de thèse. Cet édifice en béton armée est un démonstrateur instrumenté par un réseau de capteurs sans fils permettant de connaitre l’évolution de la température, de l’humidité et le niveau de déformation internes du béton armé à six endroits critiques de la structureThe objective of this thesis is to conduct research on the use of contactless technologies for structural health monitoring. The research involves scientific and technological developments to understand the functioning of wireless sensor networks in a heterogeneous environment composed of cement, aggregates, water and frames. First, our studies focus on reflection and transmission coefficients measurements of electromagnetic waves in the concrete. The realization of a communication between two Patch antennas embedded in concrete confirmed concrete moisture effect on radio waves attenuation. This analysis led to the identification of the dielectric properties of concrete at 860 MHz frequency. Later we studied the effect of various reinforced bar configurations (rebar placement, rebar radius, rebar period) on reflection and transmission coefficients. Then we studied and optimized a wireless sensor network topology to be embedded in concrete. The optimization takes into account the characteristics of sensor nodes, link budget between the communicating sensor node and the gateway and the lifespan of a node. Finally, the design and realization of a "reinforced concrete structure" of 3 m height enable to validate the different studies discussed during the thesis work. This reinforced concrete structure is an instrumented demonstrator of wireless sensor network enabling the knowledge of internal temperature, humidity and strain evolutions of a reinforced concrete in six critical areas of the structure
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Safinowski, Pawel. "Diagnostic ultrasonore de la dégradation mécanique et structurale du béton." Phd thesis, Ecole Centrale de Lille, 2011. http://tel.archives-ouvertes.fr/tel-00664281.
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Le travail présenté dans ce mémoire concerne le développement d'outils pour le diagnostic non-destructif et sans contact de l'état (dégradation) des matériaux de construction, principalement du béton. La thèse est focalisée sur deux techniques d'évaluation utilisant la propagation des ondes ultra-sonores : l'étude de la propagation des ondes de surface et l'analyse des coefficients de réflexion en fonction de l'angle d'incidence (réflectométrie). La partie théorique du travail présente les bases de la modélisation des phénomènes considérés, ainsi que la mise en oeuvre des modèles décrits dans la résolution des problèmes inverses. Un logiciel utilisant des algorithmes d'optimisation pour l'identification des paramètres du modèle sur la base des données de mesure est développé dans le cadre ce travail. La partie expérimentale présente le développement de deux systèmes de mesures ainsi que leur utilisation en laboratoire et sur le terrain. Le but de cette partie est non seulement de développer des outils expérimentaux mais aussi de les rendre opérationnels pour une utilisation courante. Les applications des outils développés pour le diagnostic sont discutées sur la base d'exemples de résultats obtenus en laboratoire et in situ. Ils permettent de spécifier les paramètres tels que la profondeur de la dégradation, la vitesse des ondes de surface et des ondes transversales en fonction de la profondeur pour le matériau testé ainsi que la perméabilité de surface, la porosité et la tortuosité du matériau testé.
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Pokorný, Jan. "Bytový dům Prostějov, stavebně technologická příprava stavby." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409939.
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In my diploma thesis, I focus on a building technology project of an apartment house in Prostějov. My work aims to design an optimal construction process. The thesis consists of a technical report, coordination drawing, project of the building site, building machines and mechanisms, time schedule and financial plan, description of technological process of the ventilated facade and of the monolithic reinforced concrete vertical structures including quality controls and testing plans. The process of making ventilated facade in comparison with the ETICS system is presented in more detail. Because the construction works take place in a city centre, the study of noise on the construction site is included as well.
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Fridlender, Jean-Marc. "Le pouvoir managérial dans les sociétés de contrôle. Socialisation de la psyché dans les organisations hypermodernes." Phd thesis, Université Paris-Diderot - Paris VII, 2008. http://tel.archives-ouvertes.fr/tel-00631614.
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Notre thèse tente d'appréhender la dimension psycho-sociale du pouvoir managerial et la dynamique sociétale qu'il crée, en conjuguant les conceptions foucaldiennes et sociocliniques du pouvoir. Plus précisément, nous étudions la structure de médiation globale déployée par les organisations de grande taille dites hypermodernes, dont l'action se situe à la confluence des registres gouvernemental, idéologique et psychologique. Notre recherche décrit un mode de socialisation caractéristique qui procède d'un étayage réciproque entre fonctionnement de la psyché et fonctionnement de l'organisation, induit par ses dispositifs de pouvoir manageriaux. Nous identifions une systémique hégémonique de normalisation comportementale basée sur le contrôle du processus de subjectivation. Ce faisant, nous esquissons une phénoménologie du régime de pouvoir managerial en tant que biopouvoir typique des sociétés de contrôle. Nous instruisons la condition psychique et subjective de l'individu-sujet contemporain, nous interrogeons sa portée politique au regard de la forme d'autonomie, la possibilité d'émancipation et la gouvernementalité engendrées. Notre problématisation, de manière non déterministe, considère le risque totalitaire d'un tel biopouvoir à la systémique globalisante. Notre approche socioclinique transdisciplinaire complémentariste articule une série de schèmes théoriques issus de corpus variés, pour ainsi élaborer différents niveaux d'analyse et une multi-problématisation de notre objet d'étude. Sur le plan empirique, notre travail s'est focalisé sur un décryptage de la puissance discriminante du dispositif de pouvoir managerial sous l'angle du contrôle du gouvernement de soi.
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Slováček, Ondřej. "Stavebně technologický projekt polyfunkčního domu Sokolská 5 v Olomouci." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372119.
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The subject of this diploma thesis is the elaboration of the building project of Polyfunkční dům Sokolská 5. In the course of the diploma thesis is elaborated a summary technical report, report of building site and drawings for individual stages. The implementation of the waterproofing of the base structure and the reinforced concrete monolithic skeleton are subject to technological regulations and control and test plans. In this work the object time and financial plan, the use of machines and mechanisms and health and safety at work are also solved. For the main building objects, an item budget and a detailed schedule are prepared. Part of this work is also the calculation of the heat transfer through the envelope of the building.
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Hladký, Dominik. "Obytný areál Ponavia park v Brně, příprava a organizace stavby." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409926.
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This thesis deals with the construction process of the apartment house Ponavia Park located in Brno. The thesis solves the individual realization phases of the main building phase. Building site equipment is designed for the projected construction process in three different variations. A technical report is also included in the building site. Critical points within the transport of materials and machines are also verified. A financial plan for the whole building is made as an summarizing time schedule for the apartment building. The sources for the financial plan are the figures taken from the Czech building objects classifications (JKSO). The summarizing time schedule is made in MS Projekt software and it’s designed as a Gantt diagram. A design of the main building machines and mechanisms was also made for the projected construction process. All of the machines were assessed for their respective required function on the building site. Also included in this thesis is a construction method for the reinforced concrete structures. The construction method deals with the realization process of waterproof concrete, reinforcement binding, formwork of the vertical and horizontal structures and also the process of concrete curing. The construction method is followed up by quality control and test plans for reinforced concrete structures, and a construction site safety plan that is made in the form of predicted main safety risks at the building site. For the noise load on the surrounding buildings a noise study is made. The study examines the intensity of noise in the protected outdoor space. This study was made in the Hluk+ software. The thesis also includes an item budget for the apartment house that was made in Build Power S software.
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"Experimental studies on particle damping technology for electronics manufacturing equipment." 2002. http://library.cuhk.edu.hk/record=b5891065.
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Chan Kwong-wah.Thesis (M.Phil.)--Chinese University of Hong Kong, 2002.
Includes bibliographical references (leaves 85-87).
Abstracts in English and Chinese.
LIST OF FIGURES --- p.vii
LIST OF TABLES --- p.xi
Chapter 1 --- INTRODUCTION --- p.1
Chapter 1.1 --- Background --- p.1
Chapter 1.1.1 --- Vibration Control --- p.1
Chapter 1.1.2 --- Passive Damping and Particle Damping Technology --- p.2
Chapter 1.2 --- Literature Review --- p.4
Chapter 1.3 --- Research Objective --- p.7
Chapter 1.4 --- Organization of the Thesis --- p.7
Chapter 2 --- PARTICLE DAMPING CHARACTERISTICS AND FEASIBILITY --- p.9
Chapter 2.1 --- Particle Damping Characteristics --- p.9
Chapter 2.1.1 --- Energy Balance in SDOF System --- p.9
Chapter 2.1.2 --- Energy Dissipation Mechanisms in Particle Damping --- p.10
Chapter 2.2 --- Particle Damping Feasibility --- p.15
Chapter 2.2.1 --- Cantilever Beam Experiment with Free Vibration --- p.15
Chapter 2.2.2 --- Effectiveness of Particle Damping --- p.17
Chapter 3 --- A STUDY ON PACKING RATIO AND GRANULE SIZE --- p.19
Chapter 3.1 --- Experimental Setup --- p.19
Chapter 3.2 --- Effect of Packing Ratio --- p.23
Chapter 3.3 --- Effect of Granule Size --- p.24
Chapter 3.4 --- Damping Ratio Estimation --- p.25
Chapter 3.5 --- Trends of Damping Ratio against Packing Ratio --- p.28
Chapter 3.6 --- Trends of Damping Ratio against Granule Size --- p.32
Chapter 3.7 --- Conclusions --- p.35
Chapter 4 --- APPLICATION OF PARTICLE DAMPING ON BOND ARM --- p.36
Chapter 4.1 --- Identification of Structural Vibration --- p.37
Chapter 4.2 --- Finite Element Modeling --- p.39
Chapter 4.2.1 --- Model of Bond Arm --- p.39
Chapter 4.2.2 --- Material Properties --- p.40
Chapter 4.2.3 --- Modes of Frequencies --- p.40
Chapter 4.2.4 --- Mode Shapes of Bond Arm --- p.41
Chapter 4.3 --- Experimental Setup and Procedure --- p.41
Chapter 4.4 --- Design of Particle Enclosure --- p.43
Chapter 4.5 --- System Parametric Study --- p.44
Chapter 4.5.1 --- Effect of Granule Sizes --- p.44
Chapter 4.5.2 --- Effect of Packing Ratios --- p.47
Chapter 4.5.3 --- Effect of Different Materials of Particle Enclosure --- p.50
Chapter 4.5.4 --- Effect of Structural Form of Enclosure --- p.52
Chapter 4.5.5 --- Effect of Number of Chambers Filled --- p.53
Chapter 4.5.6 --- Effect of Different Locations of Particle Enclosure --- p.55
Chapter 4.6 --- Conclusions --- p.56
Chapter 5 --- TEST AND ANALYSIS OF BOND HEAD STAND WITH PARTICLE DAMPING --- p.57
Chapter 5.1 --- Ways of Implementation --- p.58
Chapter 5.1.1 --- Factor of Mode Shape --- p.59
Chapter 5.1.2 --- Stress Concentration Analysis --- p.59
Chapter 5.2 --- Experimental Setup --- p.60
Chapter 5.3 --- Bond Head Stand with Small Force Excitation --- p.62
Chapter 5.3.1 --- Measurement Data --- p.62
Chapter 5.4 --- Bond Head Stand with Large Force Excitation --- p.70
Chapter 5.5 --- Effect of Packing Ratio at Different Frequency Ranges --- p.71
Chapter 5.6 --- Discussions --- p.80
Chapter 6 --- CONCLUSION --- p.82
Chapter 6.1 --- Summary --- p.82
Chapter 6.2 --- Future Work --- p.84
BIBLIOGRAPHY --- p.85
APPENDIX
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(12246642), James Lawrence Fox. "Bioengineering technology of quick grass establishment for erosion control on railway batters." Thesis, 2022. https://figshare.com/articles/thesis/Bioengineering_technology_of_quick_grass_establishment_for_erosion_control_on_railway_batters/19365482.
Full textAbstract:
The erosion of railway batters is inevitable as they are constructed with soil. The deteriorating batters could undermine the structural integrity of the rail formation. This thesis aimed to research the quick establishment of grass on these steeply sloping batters to minimise erosion. The major research tools used in this investigation included seed germination experiments, quantitative assessment of soil loss due to rainfall induced erosion and single and multi -site field trials to demonstrate large scale application of a bio-engineering approach for railway batter erosion control.
Initially research was carried out in a laboratory to address the poor germination of Buffel (Cenchrus ciliaris) grass seeds and to develop ways to advance germination to increase canopy cover. The effects of different germination media, concentration and soaking duration in sulphuric acid (H2SO4) on seed germination were evaluated. Germination was most successful when seeds were soaked for four minutes with undiluted H2SO4. Thus it was established that undiluted H2SO4 treatment may be employed for improving Buffel seed germination, provided safety issues for bulk handling are addressed.
Research at the Gregory experimental site presents a comparative field study on rapid grass establishment with different weight ratios of grass species mixtures on batters, aided by drip line irrigation, to reduce erosion. Annual Jap millet (Echinochloa esculenta) and perennial Buffel grasses were primarily used as vegetation covers on experimental batter plots. Results revealed that after three weeks of establishment the annual species significantly reduced soil erosion compared to the perennial species. Alternately after eight months, the slow growing Buffel achieved over 80% cover and became as effective as the rapid growing Jap millet, reducing soil loss by over 70% compared to 0% cover control plots.
The single site field trial at Holmes cutting used a gravity driven drip irrigation system to establish the grasses. Through observational research both cuttings at the site achieved an effective canopy cover of 70-80% within 12 weeks, significantly reducing eroded soil subsiding onto the track.
The Bauhinia Regional Rail Project (BRRP) was a large scale field application, combining improved germination procedures and advanced bioengineering techniques to establish an accelerated canopy cover. Satisfactory growth was shown by Buffel and Rhodes grasses on the railway batters within a week of seeding with pre - germinated seeds where the irrigation water was secured. The bioengineering techniques showed the feasibility of developing sufficient grass cover within eight weeks after seeding of railway batters.
Across these studies, strong evidence can be seen for the advantages of using bioengineering techniques to promote the growth of grass to mitigate erosion on the steep slopes of railway batters.
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Sinqotho, Thembeka Maureen. "Case based learning in the undergraduate nursing programme at a University of Technology : a case study." Thesis, 2015. http://hdl.handle.net/10321/1408.
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Submitted in fulfillment of the requirements for the Degree in Masters of Technology in Nursing, Durban University of Technology, Durban, South Africa, 2015.Background The current health care system in South Africa and its diverse settings of health care delivery system require a nurse who can make decisions, think critically, solve problems and work effectively in a team. Traditional nursing education teaching strategies have over the years relied on didactic and often passive approaches to learning. In pursuit of quality, academics and students must be continually engaged in a process of finding opportunities for improving the teaching and learning process. Purpose of the study The purpose of this study was to evaluate the structure and the process in case based learning at the University of Technology. Methodology This study is qualitative in nature, governed by an interpretive paradigm. This is a case study, which enabled the researcher to merge student interview data with records in order to gain insight into the activities and details of case based learning as practised at the University of Technology under study. Most importantly, the case study method was deemed appropriate for the current study, since case-based learning as a pedagogical approach (and a case) cannot be abstracted from its context for the purposes of study. Case based learning is evaluated in its context namely, the undergraduate nursing programme, using the Donabedian framework of structure, process and product. Results The study recorded that students were positive towards case based learning though some identified dynamics of working in groups as demerits of case based learning. The structures that are in place in the programme and the CBL processes are adequate and support CBL. There are however areas that need attention such as the qualification of the programme coordinator, the size of the class-rooms and the service of the computer laboratory. Conclusion The study found that apart from a few minor discrepancies, case based learning is sufficiently implemented, and experienced as invaluable by students, at the University of Technology under study.
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Santos, Diogo Filipe Moreira dos. "Development of structured catalysts for pollution control." Doctoral thesis, 2019. https://hdl.handle.net/10216/120904.
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Santos, Diogo Filipe Moreira dos. "Development of structured catalysts for pollution control." Tese, 2019. https://hdl.handle.net/10216/120904.
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César, Manuel Teixeira Brás. "Vibration Control of Building Structures using MagnetoRheological Dampers." Doctoral thesis, 2015. https://repositorio-aberto.up.pt/handle/10216/96410.
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César, Manuel Teixeira Brás. "Vibration Control of Building Structures using MagnetoRheological Dampers." Tese, 2015. https://repositorio-aberto.up.pt/handle/10216/96410.
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Barkhuizen, Willem Frederik. "An integrated systems approach to risk management within a technology driven industry using the design structure matrix and fuzzy logic." Thesis, 2012. http://hdl.handle.net/10210/5376.
Full textAbstract:
D.Ing.“Innovation is the act of introducing something new” (Byrd & Brown, 2003). When companies are competing on the technology “playground” they need to be innovative. By analysis according to Byrd & Brown (Byrd & Brown, 2003) the “act of introducing”, relates to risk taking, and the “new” relates to creativity, and therefore these concepts, creativity and risk taking, in combination, are what innovation is all about. Risk management has become one of the greatest challenges of the 21st century, and one of the main components in innovation and the technology driven industry, intensifying the need for a systematic approach to managing uncertainties. During the development and design of complex engineering products, the input and teamwork of multiple participants from various backgrounds are required resulting in complex interactions. Risk interactions exist between the functional and physical elements within such a system and its sub-systems in various dimensions such as spatial interaction, information interaction etc. The relationships are of a multi-dimensional complexity that cannot be simplified using the standard task management tools (Yassine A. A., 2004). To find a meaningful starting point for the seemingly boundless subject of risk management the research takes a step back into the basic definition of risk management and follows an exploratory research methodology to explore each of the risk management processes (risk assessment, risk identification, risk analysis, risk evaluation, risk treatment and risk monitoring and review) and how these processes can be enhanced using the design structure matrix (DSM) and fuzzy logic thinking. The approach to risk management within an organisation should be seen as a holistic approach similar to the total quality management process, providing the ii opportunity to incorporated risk management during the design process as a concurrent task. The risk management model is then developed concurrently (during the design phase) using product development methodologies such as conceptual modeling and prototyping, and ultimately the prototype is tested using a case study. Finally resulting in a clustered DSM providing a visual representation of the system risk areas similar to the methodology used in Finite Element Analysis (FEA). The research combines alternative system representation and analysis techniques (Warfield, 2005), in particular the design structure matrix, and fuzzy logic to quantify the risk management effort neccessary to deal with uncertain and imprecise interactions between system elements.
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Mutezo, Ashley Teedzwi. "Small and medium enterprise financing and credit rationing : the role of banks in South Africa." Thesis, 2015. http://hdl.handle.net/10500/23479.
Full textAbstract:
The potential of small and medium enterprises (SMEs) in promoting economic growth in both developed and developing countries is widely accepted and documented by both scholars and policy makers. Particularly lacking are studies on the evidence in support of the importance of credit rationing to the sustainability of SMEs in an emerging economy like South Africa’s. This specific problem, especially in the developing countries, has been identified as the major bottleneck in realising socio-economic potentials of SMEs in those countries. However, one of the major ways of addressing the challenge of inadequate funding that exists within the SME sector is the use of bank credit. This study was therefore undertaken to explore the role of commercial banks in the provision of credit to the SMEs in South Africa.
This study focuses on the issue of the relationship between the banking industry and SMEs. In particular, the problem of credit rationing of, and discrimination against SMEs by commercial banks was investigated. Because credit rationing and finance gaps can stem from imperfections on either supply-side (banks), or demand-side (SMEs), or both, the intention of the study was to examine both of these variables in order to uncover the implications of their relationships.
The empirical analysis is based on survey data collected by means of a structured questionnaire which was distributed amongst banks and SME borrowers in the Gauteng Province of South Africa. Contrary to the general view that commercial banks are disinclined to provide credit to SMEs, the study found that South African banks are keen to serve the SMEs and are therefore making efforts to penetrate this potentially profitable market segment. However, several obstacles are potentially restricting the involvement of banks with SMEs in South Africa. The findings revealed that regulations such as the Financial Intelligence Centre Act (FICA) and the National Credit Act (NCA) came out strongly as major hindrances of bank financing to SMEs. Furthermore, it was shown that compliance with the NCA was ranked higher than credit history and profitability as a factor hindering the approval of SME loans.
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However, by using the structural equation modelling (SEM), the results also show that there is a positive and significant influence of lending technology and collateral on the supply of credit to SMEs. Variables such as creditworthiness, collateral and e-banking were found to have a positive and significant impact on the provision of credit to SMEs by commercial banks. For both the supply- and demand-side analysis, technology came out as the most important predictor of SME access to finance. This means that banks should strive to align their lending techniques with the dynamic technological developments so as to reach as many SMEs as possible even in the geographically dispersed regions. It is anticipated that improving SME access to bank credit could be the key to the growth and sustainability of SMEs, the alleviation of poverty and unemployment; and consequently leading to the growth of the South African economy.Business Management
D. Com. (Business Management)
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(8079911), Jie Xiong. "AN ADAPTIVE PERSONALIZED DAYLIGHTING CONTROL APPROACH FOR OPTIMAL VISUAL SATISFACTION AND LIGHTING ENERGY USE IN OFFICES." Thesis, 2019.
Find full textAbstract:
In perimeter building zones with glass façades, controllable fenestration (daylighting/shading) and electric lighting systems are used as comfort delivery systems under dynamic weather conditions, and their operation affects daylight provision, outside view, lighting energy use, as well as overall occupant satisfaction with the visual environment. A well-designed daylighting and lighting control should be able to achieve high level of satisfaction while minimizing lighting energy consumption. Existing daylighting control studies focus on minimizing energy use with general visual comfort constraints, when adaptive and personalized controls are needed in high performance office buildings. Therefore, reliable and efficient models and methods for learning occupants’ personalized visual preference or satisfaction are required, and the development of optimal daylighting controls requires integrated considerations of visual preference/satisfaction and energy use.
In this Dissertation, a novel method is presented first for developing personalized visual satisfaction profiles in daylit offices using Bayesian inference. Unlike previous studies based on action data, a set of experiments with human subjects was designed and conducted to collect comparative visual preference data (by changing visual conditions) in private offices. A probit model structure was adopted to connect the comparative preference with a latent satisfaction utility model, assumed in the form of a parametrized Gaussian bell function. The distinct visual satisfaction models were then inferred using Bayesian approach with preference data. The posterior estimations of model parameters, and inferred satisfaction utility functions were investigated and compared, with results reflecting the different overall visual preference characteristics discovered for each person.
Second, we present an online visual preference elicitation learning framework for efficiently learning and eliciting occupants’ visual preference profiles and hidden satisfaction utilities. Another set of experiments with human subjects was conducted to implement the proposed learning algorithm in order to validate the feasibility of the method. A combination of Thompson sampling and pure exploration (uncertainty learning) methods was used to balance exploration and exploitation when targeting the near-maximum area of utility during the learning process. Distinctive visual preference profiles of 13 subjects were learned under different weather conditions, demonstrating the feasibility of the learning framework. Entropy of the distribution of the most preferred visual condition is computed for each learned preference profile to quantify the certainty. Learning speed varies with subjects, but using a single variable model (vertical illuminance on the eye), most subjects could be learned to an acceptable certainty level within one day of stable weather, which shows the efficiency of the method (learning outcomes).
Finally, a personalized shading control framework is developed to maximize occupant satisfaction while minimizing lighting energy use in daylit offices with roller shades. An integrated lighting-daylighting simulation model is used to predict lighting energy use while it also provides inputs for computing personalized visual preference profiles, previously developed using Bayesian inference from comparative preference data. The satisfaction utility and the predicted lighting energy use are then used to form an optimization framework. We demonstrate the results of: (i) a single objective formulation, where the satisfaction utility is simply used as a constraint to when minimizing lighting energy use and (ii) a multi-objective optimization scheme, where the satisfaction utility and predicted lighting energy use are formulated as parallel objectives. Unlike previous studies, we present a novel way to apply the MOO without assigning arbitrary weights to objectives: allowing occupants to be the final decision makers in real-time balancing between their personalized visual satisfaction and energy use considerations, within dynamic hidden optimal bounds – through a simple interface.
In summary, we present the first method to incorporate personalized visual preferences in optimal daylighting control, with energy use considerations, without using generic occupant behavior models or discomfort-based assumptions.