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1
Scetbon, Meyer. "Advances in Optimal Transport : Low-Rank Structures and Applications in Machine Learning." Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAG002.
Abstract:
Les progrès récents en matière de matériel informatique, tels que le développement d'accélérateurs hautement parallèles, et la perméabilité croissante entre l'informatique, les statistiques, l'optimisation et les mathématiques appliquées ont donné naissance à une nouvelle génération d'outils capables de résoudre des problèmes d'apprentissage automatique (AA) de plus en plus complexes. Parmi ces nouveaux défis, certains nécessitent la comparaison de nuages de points ou de mesures de probabilité. Le transport optimal (TO) est devenu un outil largement utilisé dans ce contexte en raison de sa capacité à fournir une géométrie naturelle dans l'espace des distributions et à offrir une nouvelle perspective pour traiter les problèmes d'AA lorsqu'ils sont levés dans cet espace. À partir d'une fonction de coût (par exemple, une distance) défini entre les points où sont supportées les mesures, le TO consiste à trouver un couplage entre les deux mesures qui soit optimal par rapport à ce coût. En d'autres termes, le TO étend naturellement le coût entre deux points à coût entre des histogrammes de points, ou des mesures de probabilité, sous la forme d'un problème d'optimisation. De plus, en raison de sa forte composante géométrique, le TO fait l'objet d'une riche théorie mathématique sur laquelle les praticiens peuvent s'appuyer pour construire et étudier leurs modèles.Pourtant, dans leur forme originale, telle qu'elle a été proposée par Kantorovich, les distances de TO ne sont pas bien adaptées aux problèmes appliqués : (i) le calcul du TO entre des mesures discrètes revient à résoudre un programme linéaire coûteux qui requiert une complexité supercubique en le nombre de points; (ii) l'estimation du TO à l'aide de mesures échantillonnées est condamnée par la malédiction de la dimensionnalité, le TO est donc susceptible d'être dépourvue de sens lorsqu'elle est utilisée sur des échantillons provenant de densités en haute dimension. En dépit de ces difficultés, le TO s'est révélée très prometteur dans diverses applications d'AA, et les recherches en cours visent à relever ces défis et à rendre le TO plus accessible et utilisable dans la pratique.La principale approche pour pallier ces problèmes consiste à régulariser le problème d'optimisation en ajoutant un terme d'entropie a l'objectif. En ajoutant de l'entropie, on peut alors résoudre une version régularisée du problème de TO en temps et en mémoire quadratiques à l'aide de l'algorithme de Sinkhorn. De plus, cette régularisation permet d'éviter la malédiction de la dimensionnalité à condition d'avoir ajouté suffisamment d'entropie. Même si la régularisation entropique a amélioré à la fois le coût de calcul et les propriétés statistiques du transport optimal, elle souffre toujours d'une complexité quadratique qui empêche son utilisation pour des applications à grande échelle. Un des principes directeurs de cette thèse est qu'il existe encore de nombreuses opportunités de recherche pour développer de nouveaux outils algorithmiques qui peuvent exploiter ou étendre ce mode de pensée afin de rendre le TO applicable à des problèmes à grande échelle.Cette thèse se compose de deux parties principales. Dans la première partie, nous proposons de nouveaux schémas de régularisation du problème de TO et de sa variante quadratique, à savoir le problème de Gromov-Wasserstein (GW), en considérant des factorisations de bas rang à la fois du coût sous-jacent et du couplage résolvant le problème de TO. Ces nouveaux schémas de calcul ouvrent la voie à l'utilisation du problème TO dans un cadre à grande échelle. Dans la deuxième partie, nous montrons que le TO peut également offrir une nouvelle perspective sur des problèmes d'AA de longue date dès lors qu'ils sont formalisés dans l'espace des distributions. Nous adoptons ce point de vue sur deux problèmes appliqués, à savoir en équité et en robustesse, et proposons de nouvelles approches pour les aborder à l'aide du TORecent advances in hardware, such as the development of highly-parallel accelerators, and the growing permeabilitybetween computer science, statistics, optimization and applied mathematics have brought forward a new generation of tools,capable of addressing increasingly complex machine learning (ML) problems. Among these new challenges, some require the comparison of point clouds or probability measures. Optimal transport (OT) has become a widely used tool in this context due to its ability to provide a natural geometry in the space of distributions and offer a new perspective for dealing with ML problems when lifted into this space. Starting from a cost function (e.g. a distance) on the space on which measures are supported, OT consists in finding a mapping or coupling between both measures that is optimal with respect to that cost. In other words, OT naturally extends the ground cost between two points to a discrepancy function between histograms of points, or probability measures, in the form of an optimization problem. Further, as a consequence of its strong geometric component, OT is the object of a rich mathematical theory regarding its metric and topological properties, on which ML practitioners can rely to build and study their models.Yet, in their original form, as proposed by Kantorovich, OT distances are not well suited for applied problems: (i) computing OT between discrete distributions amounts to solving a large and expensive network flow problem which requires a supercubic complexity; (ii) estimating OT using sampled measures is doomed by the curse of dimensionality: the sample convergence rate of OT is exponentially slow w.r.t. the dimension of the ambient space, therefore OT is likely to be meaningless when used on samples from high-dimensional densities. Despite these challenges, OT has shown great promise in various machine learning applications, and ongoing research is aimed at addressing these challenges and making OT more accessible and usable in practice.The main approach to alleviate these issues consists in regularizing the optimization problem using an entropic regularization. By adding entropy to the objective function, one can now solves a regularized version of the OT problem in quadratic time and memory using the Sinkhorn algorithm. In addition, this regularization allows to avoid the curse of dimensionality as long as enough entropy has been added.Even though entropic regularization has improved both the computational cost and the statistical properties of optimal transport, it still suffers from a quadratic complexity that prevents its use for large-scale applications. One guiding principle of this thesis is that there are still many research opportunities to develop new algorithmic tools that can exploit or extend this way of thinking in order to make OT applicable to large-scale problems.This thesis consists of two main parts. In the first part, we propose new regularization schemes of the OT problem and its quadratic variant, namely the Gromov-Wasserstein (GW) problem, by considering low-rank factorization of both the underlying cost and the coupling solving the OT problem itself. These new computational schemes pave the way for the use of OT in the large-scale setting. In the second part, we show that OT can also offer new perspective on longstanding ML problems once lifted into the set of distributions. We adopt this point of view on two applied problems in fairness and robustness respectively and propose new approaches to tackle them using OT
2
May-Smith, Timothy Christopher. "Pulsed laser deposition of thick multilayer garnet crystal films for waveguide laser devices." Thesis, University of Southampton, 2005. https://eprints.soton.ac.uk/65499/.
Abstract:
The main aim of this project was to use the technique of pulsed laser deposition (PLD) to fabricate thick multilayered garnet crystal planar waveguides with rare-earth ion doped cores for use as planar waveguide laser devices. Planar waveguides are of interest because of the implications of their structure, which allows for lasing, pumping and heat dissipation to each have a unique axis of operation, and the confinement properties of planar waveguide lasers result in lower pump power thresholds, higher gains per unit pump power and higher efficiencies than their bulk counterparts. Thick planar waveguide lasers are desirable because they can be pumped by high power diode laser arrays, and suffer less from the detrimental effect of particulates (a practically unavoidable side effect of the PLD technique). The use of multilayers allows a device with a high numerical aperture to be fabricated and the careful choice of the cladding layer thicknesses and refractive indices allows good beam quality output to be produced using diode pumping. Other aims of the project were to fabricate a self-imaging waveguide amplifier and explore other applications of thick garnet crystal films such as the possibility of using a highly doped thick film as a thin-disk laser device. Now that the technique of thick garnet crystal film deposition via multiple growth runs has been established, the potential of thick garnet crystal films needs to be exploited. Multilayer structures with more ideal geometries need to be fabricated to make optimal waveguide laser devices and difficulties resulting from thermal expansion mismatch need to be addressed so that side-pumping can be performed with diode laser arrays.
3
Xakalashe, Buhle Sinaye. "Removal of Phosphorus from Silicon Melts by Vacuum Refining." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for materialteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-16350.
Abstract:
Induction vacuum refining testwork has been carried out for the removal of phosphorus from silicon melts. This work is of interest for the production of solar-grade silicon, since phosphorus is hard to remove from silicon and an important impurity in solar cells.
4
Wilshere, Brian. "Brian Wilshere : the drummer as composer." Thesis, Goldsmiths College (University of London), 2007. http://research.gold.ac.uk/6599/.
Abstract:
This thesis consists of a portfolio of compositions with the addition of 5 CD's, commentaries on selected compositions and additional written material placing submitted work in context. It is that context which supplies the title of the thesis. It is my contention that a composers' work is affected by the culture surrounding them, and that that culture contains a number of musical and social factors which impinge upon a composers' interaction with the world. In my case, I seek to show how a combination of my formative experiences and somewhat unusual musical background have influenced my work and contributed to its unique qualities. Firstly, I outline the aesthetic principles underpinning my music. My journey through the world of music and music education has given me the ability to forge my own aesthetic and compositional path, and this thesis reflects upon this process in some detail in order to illuminate those aspects of my own musical practice which I believe may serve to contribute to the debates currently surrounding music. In doing this, I attempt to both redefine musical categorizations according to consumer behaviour rather than musicological opinion and argue for definitions which are as culturally neutral as possible. I then describe in detail the compositional procedures utilized in my work, and reflect upon the extent to which these are governed by my formative experiences. Finally, the more large scale submitted pieces have accompanying commentaries, highlighting aspects of musical practice or background which may be relevant. 'Brian Wilshere: The Drummer as Composer' is a summation of several years in the life of a drummer/composer attempting to earn a living, write some music and obtain performances of that music.
5
Faidah, Adel Saleh. "Screen printed layers of CdS for solar cells." Thesis, Durham University, 1988. http://etheses.dur.ac.uk/6599/.
Abstract:
It is generally accepted nowadays that a significant cost reduction in terrestrial solar cell application could be brought about by investigating alternative fabrication techniques for solar cells. It is believed that screen printing (or the so called thick film technique) is one such technique which promises a potentially low cost method for fabricating flexible, large area solar energy conversion cells. The active research on this technique started in 1976 in Japan. However, it was not until 1983, that wide interest developed when the Matsushita group in Japan reported an efficiency of 12.8% for their entirely screen printed CdS/CdTe solar cells. This was the highest reported efficiency for any thin film solar cell. However, the details of the fabrication processes of these cells were not reported and several scientific groups in the world started to explore this technique. The first published report was in 1985. In the last few years these groups have reported results on various aspects of this technique. Nevertheless there are still major parameters to be investigated. This thesis represents a concise reference for the application of the screen printing technique to solar cells. In the course of this study many new investigations have been made which supplement the previous work by other groups. Starting with a pure CdS powder with suitable grain size and distribution is a prerequisite for achieving the best morphological and electrical behaviour of screen printed layers of CdS. Careful paste mixing is of uppermost importance which can override any other parameters involved in the fabrication processes. It is essential to impose restricted sintering conditions for adequate utilization of the doping and fluxing function of the CdCl(_2) material. Standardization of the printing, preparation and sintering conditions involved in the fabrication processes were necessary to ensure reproducible CdS layers. Good quality screen printed layers were fabricated on soda lime substrates. The significance of other substrate materials for CdS preparation was also investigated and optimum substrate choice is suggested. The properties of the CdS screen printed layers were investigated by forming simple Schottky devices and more complicated heterojunction solar cells. Good rectification behaviour of the Schottky diodes was achieved. The CdS/CdTe solar cells revealed a wide spectral response. However, the photovoltaic behaviour was relatively poor largely due to the high resistivity of the CdTe part of the cell structure.
6
Mamani, Adriana Elizabeth, and Juana Lourdes Quena. "El Abordaje del Trabajador Social en las tramas socio-familiar de niños que presentan hipoacusia infantil severa." Bachelor's thesis, Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y Sociales, 2014. http://bdigital.uncu.edu.ar/6599.
Abstract:
La presente tesina tiene como finalidad el abordaje de la problemática de la discapacidad auditiva denominada hipoacusia, comprendiendo los diferentes momentos que transita el niño/a y su familia, ya sea en el ámbito de salud con su tratamiento médico, el educativo en su inserción en educación especial y, la relación con los profesionales que intervienen en dicho proceso.
Es importante el rol de la familia y su lucha frente al encuentro de la discapacidad de uno de sus miembros, el ámbito de la familia es el primer ámbito en donde se lleva a cabo el proceso de socialización primaria, para su posterior inclusión en la sociedad. Por lo tanto, la familia, la escuela, el Trabajo Social, los profesionales que intervienen en el tratamiento de los niños con hipoacusia, son parte de un proceso que deben trabajar mancomunadamente buscando la inclusión, participación y la igualdad como sujetos de derecho, que permita el desarrollo máximo de sus potencialidades.Fil: Mamani, Adriana Elizabeth. Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y Sociales.
Fil: Quena, Juana Lourdes. Universidad Nacional de Cuyo. Facultad de Ciencias Políticas y Sociales.
7
Fantini, Enrico. "Ibeacon una nuova tecnologia per la localizzazione in ambienti chiusi." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amslaurea.unibo.it/6599/.
8
Condrea, Eliza Patricia. "Modelling, analysis and forecasting of deep sea oxygen isotope variations response to orbital forcing." Thesis, University of Sheffield, 2014. http://etheses.whiterose.ac.uk/6599/.
9
Previti, Alberto <1985>. "Fast and accurate numerical solutions in some problems of particle and radiation transport: synthetic acceleration for the method of short characteristics, Doppler-broadened scattering kernel, remote sensing of the cryosphere." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6599/.
Abstract:
The aim of this work is to present various aspects of numerical simulation of particle and radiation transport for industrial and environmental protection applications, to enable the analysis of complex physical processes in a fast, reliable, and efficient way.
In the first part we deal with speed-up of numerical simulation of neutron transport for nuclear reactor core analysis.
The convergence properties of the source iteration scheme of the Method of Characteristics applied to be heterogeneous structured geometries has been enhanced by means of Boundary Projection Acceleration, enabling the study of 2D and 3D geometries with transport theory without spatial homogenization.
The computational performances have been verified with the C5G7 2D and 3D benchmarks, showing a sensible reduction of iterations and CPU time.
The second part is devoted to the study of temperature-dependent elastic scattering of neutrons for heavy isotopes near to the thermal zone.
A numerical computation of the Doppler convolution of the elastic scattering kernel based on the gas model is presented, for a general energy dependent cross section and scattering law in the center of mass system.
The range of integration has been optimized employing a numerical cutoff, allowing a faster numerical evaluation of the convolution integral.
Legendre moments of the transfer kernel are subsequently obtained by direct quadrature and a numerical analysis of the convergence is presented.
In the third part we focus our attention to remote sensing applications of radiative transfer employed to investigate the Earth's cryosphere.
The photon transport equation is applied to simulate reflectivity of glaciers varying the age of the layer of snow or ice, its thickness, the presence or not other underlying layers, the degree of dust included in the snow, creating a framework able to decipher spectral signals collected by orbiting detectors.Questo lavoro si propone di presentare diversi aspetti della simulazione numerica del trasporto di particelle e di radiazione per applicazioni industriali e di protezione ambientale, per consentire l'analisi di processi fisici complessi in modo veloce, affidabile ed efficiente. Nella prima parte è trattata la velocizzazione della simulazione numerica del trasporto di neutroni per l'analisi del nocciolo di un reattore nucleare. Le proprietà di convergenza della source iteration del Metodo delle Caratteristiche applicate a geometrie strutturate eterogenee sono state migliorate per mezzo della Boundary Projection Acceleration, consentendo lo studio di geometrie 2D e 3D con la teoria del trasporto senza omogeneizzazione spaziale. Le prestazioni computazionali sono state verificate tramite il benchmark C5G7 2D e 3D, mostrando una sensibile riduzione del numero di iterazioni e del tempo di calcolo. La seconda parte è dedicata allo studio dello scattering elastico dei neutroni con isotopi pesanti in funzione della temperatura vicino alla zona termica. È presentato il calcolo numerico della convoluzione Doppler del kernel di scattering elastico col modello gas per una generale sezione d'urto dipendente dall'energia e per una generica legge di scattering nel sistema del centro di massa. L'intervallo di integrazione è stata ottimizzato utilizzando un cutoff numerico, consentendo una valutazione numerica più veloce dell'integrale. I momenti di Legendre del kernel di trasferimento sono successivamente ottenuti per quadratura diretta e validati tramite un'analisi numerica della convergenza. La terza parte è focalizzata alle applicazioni di telerilevamento del trasferimento radiativo per indagini sulla criosfera terrestre. L'equazione del trasporto per fotoni è applicata per simulare la riflettività dei ghiacciai a diverse età dello strato di neve o ghiaccio, al suo spessore, alla presenza o meno di altri strati sottostanti, al grado di polvere inclusa nella neve, creando un sistema in grado di decifrare segnali spettrali raccolti dai rivelatori orbitanti.
10
Rijn, Paul Cornelis Jacobus van. "The impact of supplementary food on a prey-predator interaction." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2002. http://dare.uva.nl/document/65999.
11
Takara, Thomas J. (Thomas Joji). "Multiple roles of the replication initiation protein Cdtl during helicase loading in S. cerevisiae." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65299.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references.
The faithful transmission of genetic information is critical for the events of cell division and propagation. In eukaryotic cells, chromosomal replication is carefully coordinated with the cell cycle to ensure that the entire genome is replicated exactly once prior to cell division. Underpinning this coordination is the tightly regulated loading and activation of the eukaryotic replicative DNA helicase, the hetero-hexameric Mcm2-7 complex. As cells enter G1 phase of the cell cycle, all potential sites of replication initiation are selected by the loading of inactive Mcm2-7 double hexamers. The anti-parallel orientation of the Mcm2-7 hexamers within the double hexamer is proposed to be critical to establish bidirectional sister replisomes upon helicase activation in S phase. Although the proteins involved in helicase loading are known, the mechanism that drives Mcm2-7 double-hexamer formation and loading is unclear. The replication initiation protein Cdtl is essential for loading Mcm2-7 onto origin DNA, but its functions during the loading event are unclear. Through analysis of Cdtl mutations, I identified regions of Cdtl that are essential for Mcm2-7 helicase binding, origin recruitment, and activation. I found that multiple Cdtl molecules are recruited to the origin during the helicase-loading process, and disrupting of the assembly of the multi-Cdtl intermediate prevents Mcm2-7 loading. Finally, I demonstrated that the Nterminal domain of Cdtl, although dispensable for stable helicase loading, is required for subsequent helicase activation and replication initiation. These findings reveal that Cdtl performs multiple functions during helicase loading and influences the competence of loaded Mcm2-7 to subsequently become activated. This work provides insight into the process of Mcm2-7 double-hexamer loading and supports a model in which Cdtl initiates Mcm2-7 double-hexamer formation early in the helicase-loading process.
by Thomas J. Takara.
Ph.D.
12
Brun, Caroline Elisabeth Hénia. "Economic and technical impacts of wind variability and intermittency on long-term generation expansion planning in the U.S." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65499.
Abstract:
Thesis (S.M. in Technology and Policy)--Massachusetts Institute of Technology, Engineering Systems Division, Technology and Policy Program, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 57-59).
Electricity power systems are a major source of carbon dioxide emissions and are thus required to change dramatically under climate policy. Large-scale deployment of wind power has emerged as one key driver of the shift from conventional fossil-fuels to renewable sources. However, technical and economic concerns are arising about the integration of variable and intermittent electricity generation technologies into the power grid. Designing optimal future power systems requires assessing real wind power capacity value as well as back-up costs. This thesis develops a static cost-minimizing generation capacity expansion model and applies it to a simplified representation of the U.S. I aggregate an hourly dataset of load and wind resource in eleven regions in order to capture the geographical diversity of the U.S. Sensitivity of the optimal generation mix over a long-term horizon with respect to different cost assumptions and policy scenarios is examined. I find that load and wind resource are negatively correlated in most U.S. regions. Under current fuel costs (average U.S. costs for year 2002 to year 2006) regional penetration of wind ranged from 0% (in the South East, Texas and South Central regions) to 22% (in the Pacific region). Under higher fuel costs as projected by the Energy Information Administration (average for the period of 2015 to 2035) penetration ranged from 0.3% (in the South East region) to 59.7% (in the North Central region). Addition of a C02 tax leads to an increase of optimal wind power penetration. Natural gas-fired units are operating with an actual capacity factor of 17% under current fuel costs and serve as back-up units to cope with load and wind resource variability. The back-up required to deal specifically with wind resource variations ranges from 0.25 to 0.51 MW of natural gas-fired installed per MW of wind power installed and represents a cost of $4/MWh on average in the U.S., under current fuel costs.
by Caroline Elisabeth Hénia Brun.
S.M.in Technology and Policy
13
Mooring, Todd A. "Changes in atmospheric eddy length with the seasonal cycle and global warming." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65599.
Abstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Physics; and, (S.B.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 59-60).
A recent article by Kidston et al. [8] demonstrates that the length of atmospheric eddies increases in simulations of future global warming. This thesis expands on Kidston et al.'s work with additional studies of eddy length in the NCEP2 reanalysis (a model-data synthesis that reconstructs past atmospheric circulation) and general circulation models (GCMs) from the Coupled Model Intercomparison Project phase 3. Eddy lengths are compared to computed values of the Rossby radius and the Rhines scale, which have been hypothesized to set the eddy length. The GCMs reproduce the seasonal variation in the eddy lengths seen in the reanalysis. To explore the effect of latent heating on the eddies, a modification to the static stability is used to calculate an effective Rossby radius. The effective Rossby radius is an improvement over the traditional dry Rossby radius in predicting the seasonal cycle of northern hemisphere eddy length, if the height scale used for calculation of the Rossby radius is the depth of the free troposphere. There is no improvement if the scale height is used instead of the free troposphere depth. However, both Rossby radii and the Rhines scale fail to explain the weaker seasonal cycle in southern hemisphere eddy length. In agreement with Kidson et al., the GCMs robustly project an increase in eddy length as the climate warms. The Rossby radii and Rhines scale are also generally projected to increase. Although it is not possible to state with confidence what process ultimately controls atmospheric eddy lengths, taken as a whole the results of this study increase confidence in the projection of future increases in eddy length.
by Todd A. Mooring.
S.B.
14
Arfin, Scott K. (Scott Kenneth). "Low power circuits and systems for wireless neural stimulation." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65999.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 155-161).
Electrical stimulation of tissues is an increasingly valuable tool for treating a variety of disorders, with applications including cardiac pacemakers, cochlear implants, visual prostheses, deep brain stimulators, spinal cord stimulators, and muscle stimulators. Brain implants for paralysis treatments are increasingly providing sensory feedback via neural stimulation. Within the field of neuroscience, the perturbation of neuronal circuits wirelessly in untethered, freely-behaving animals is of particular importance. In implantable systems, power consumption is often the limiting factor in determining battery or power coil size, cost, and level of tissue heating, with stimulation circuitry typically dominating the power budget of the entire implant. Thus, there is strong motivation to improve the energy efficiency of implantable electrical stimulators. In this thesis, I present two examples of low-power tissue stimulators. The first type is a wireless, low-power neural stimulation system for use in freely behaving animals. The system consists of an external transmitter and a miniature, implantable wireless receiver-and-stimulator utilizing a custom integrated chip built in a standard 0.5 ptm CMOS process. Low power design permits 12 days of continuous experimentation from a 5 mAh battery, extended by an automatic sleep mode that reduces standby power consumption by 2.5x. To test this device, bipolar stimulating electrodes were implanted into the songbird motor nucleus HVC of zebra finches. Single-neuron recordings revealed that wireless stimulation of HVC led to a strong increase of spiking activity in its downstream target, the robust nucleus of the arcopallium (RA). When this device was used to deliver biphasic pulses of current randomly during singing, singing activity was prematurely terminated in all birds tested. The second stimulator I present is a novel, energy-efficient electrode stimulator with feedback current regulation. This stimulator uses inductive storage and recycling of energy based on a dynamic power supply to drive an electrode in an adiabatic fashion such that energy consumption is minimized. Since there are no explicit current sources or current limiters, wasteful energy dissipation across such elements is naturally avoided. The stimulator also utilizes a shunt current-sensor to monitor and regulate the current through the electrode via feedback, thus enabling flexible and safe stimulation. The dynamic power supply allows efficient transfer of energy both to and from the electrode, and is based on a DC-DC converter topology that is used in a bidirectional fashion. In an exemplary electrode implementation, I show how the stimulator combines the efficiency of voltage control and the safety and accuracy of current control in a single low-power integrated-circuit built in a standard 0.35 pm CMOS process. I also perform a theoretical analysis of the energy efficiency that is in accord with experimental measurements. In its current proof-of-concept implementation, this stimulator achieves a 2x-3x reduction in energy consumption as compared to a conventional current-source-based stimulator operating from a fixed power supply.
by Scott Kenneth Arfin.
Ph.D.
15
Dengenis, Susanne S. (Susann Schumann), and James P. Kwasnowski. "Understanding the learning organization : an avenue to meeting today's business challenge." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/65699.
Abstract:
Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1996.Includes bibliographical references (leaves 89-92).
by Susanne S. Dengenis, James P. Kwasnowski.
M.S.
16
Chow, King Man. "An analysis of Hong Kong REIT : current and future opportunities for investors." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/65799.
Abstract:
Thesis (S.M.)--Massachusetts Institute of Technology, Sloan School of Management, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 73-76).
Real estate investment trust (REIT) is a valuable investment alternative for investors in many markets. Being home to a handful of world-class property developers, Hong Kong, the Asia financial hub, seemed to have met all the criteria to grow a REIT market rapidly. Yet, since the enactment of the Hong Kong REIT Code in 2003, the H-REIT (acronym for Hong Kong REIT) market saw only eight H-REITs being launched, lagging the growth of other REIT markets in the region. This thesis paper seeks to uncover the present investment values in H-REITs and determine what likely would shape the future of the market hence the potential value it could bring to investors, through examining the local real estate capital markets, the regulations, and the supply and demand dynamics, and conducting comparative analysis with stocks of local property companies. The study finds that the H-REITs are significantly less risky than local property stocks and offer dividend yields that in most cases are greater than the earning yields of those stocks. H-REIT offers real estate exposure, yet provides diversification effect to a portfolio of local property stocks given its low correlations with these stocks. Hurdles to market growth persist as abundance of liquidity, low yields offered by prime properties, poor reception of yield enhancement mechanisms in REITs, agency problems and questionable corporate governance of the H-REITs all contributed to suppressing both the supply and demand for local asset-backed H-REITs. Moreover, the small size of the city seems to indicate that the H-REIT market was destined to depend on cross-border deals. Thanks to the close-tie to China, Yuan-denominated cross-border REITs backed by Mainland China assets appear to be the future of the H-REIT market. While this type of deal clears some of the hurdles to grow the market, it still remains in the hands of the sponsors to add transparencies in H-REIT management structure to gain the much needed trust from investors to build a functioning market.
by King Man Chow.
S.M.
17
Yonezaki, Yoshinori. "Nonlinear optical properties of polarized structure induced in oxide glasses." 京都大学 (Kyoto University), 2008. http://hdl.handle.net/2433/65599.
Abstract:
Kyoto University (京都大学)0048
新制・論文博士
博士(工学)
乙第12249号
論工博第3998号
新制||工||1440(附属図書館)
26406
UT51-2008-L174
京都大学大学院工学研究科材料化学専攻
(主査)教授 平尾 一之, 教授 横尾 俊信, 教授 田中 勝久
学位規則第4条第2項該当
18
Rabatoko, Matheanoga Fana. "San indigenous songs as cultural heritage for inclusion in Botswana music education programmes." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65599.
Abstract:
Botswana is a heterogeneous society and therefore the elements of dualism as well as cultural pluralism should be reflected in social institutions such as schools. The Naro of D’Kar are among the few minority ethnic San groups in Botswana still practicing their indigenous songs. While the government is positively continuing to implement the recommendations of the 1994 Revised National Policy on Education, this study explored Naro music, songs and dances to find possible ways in which these intangible elements of cultural heritage could be included in the music education curriculum. A qualitative ethnomusicological approach was applied in order to provide a systematic and scientific description of the contextual and cultural aspects of Naro music practices. Participants were purposively selected as indigenous culture bearers, including both adults and children. Focus groups as well as semi-structured individual interviews contributed to rich data gathering. Moreover, an extended period of field work allowed opportunities to observe various groups of Naro participating in music, song and dance activities, leading to an in-depth perspective of the research problem. All interviews and observations were audio- or video-recorded. An interpretative data analysis strategy was employed to identify themes. Findings reveal the rich cultural heritage of the Naro of D’Kar and how this is entrenched in their indigenous songs and dances. The purpose of Naro songs are closely linked to spiritual and physical healing rituals. Data analysis unveiled four broad categories in which Naro songs and dances may be classified namely songs for worship; songs for initiation; songs for social commentary; and lastly a broad category of songs for thanksgiving, recreation, hunting and children’s playsongs. The documenting, transcribing and audio/video-recording of Naro songs as performed in their original context and setting, add valuable resources which music teachers can use to facilitate inclusion of Naro music in the Botswana curriculum. This may lead to a paradigm shift in policy development whereby principles of Multicultural Music Education (MME) are embraced. Learners are envisaged to acquire knowledge and understanding of a broader society as well as an appreciation of their own cultural heritage including language, traditions, songs, ceremonies, customs, social norms and a sense of citizenship.Dissertation (MMus)--University of Pretoria, 2017.
Music
MMus
Unrestricted
19
Mudimeli, Fhatuwani Elphus. "The early termination of credit agreements in terms of the National Credit Act 34 of 2005." Diss., University of Pretoria, 2018. http://hdl.handle.net/2263/65699.
Abstract:
This dissertation discusses and investigates the early termination of credit agreements by consumer in terms of the National Credit Act 34 of 2005 (National Credit Act). The dissertation aims to critically analyse and interrogate the rights of consumers to terminate agreement before the time allowed for in the credit agreement. My dissertation consists of four chapters. Chapter 1 is a general background and introduction to the dissertation and also provides the problem statement together with the research objectives. A short overview regarding the aspects which will be discussed in each subsequent chapter are also addressed in this chapter. Chapter 2 discusses the overview of the general principles (common law) of early termination of credit agreements in South Africa. Chapter 3 concerns the investigation of consumer’s rights in terms of the National Credit Act to terminate the credit agreements early. The National Credit Act, drastically, gives the consumer a right to terminate the credit agreements and therefore it is necessary for purposes of this dissertation to fully dissect the circumstances under which the consumer can exercise the right to terminate the credit agreements early. This dissertation, to a certain extent, also seeks to demonstrate the changes or influence that the National Credit Act has brought on the common law principles regarding the termination of credit agreements. Chapter 4 involves my comprehensive final conclusions and recommendations in relation to the heightened consumer protection by the National Credit Act as well as areas that requires further improvement to strengthen the consumer rights to termite the credit agreements early.Mini Dissertation (LLM)--University of Pretoria, 2018.
Mercantile Law
LLM
Unrestricted
20
Kapuya, Tinashe. "Comparative analysis of corporate strategies in agriculture : the internationalisation of agribusinesses in Sub-Saharan Africa." Thesis, University of Pretoria, 2018. http://hdl.handle.net/2263/65899.
Abstract:
Between 75% and 90% of the world market for agricultural commodities is controlled by four major agribusiness multinationals (MNCs), namely Archer Daniels Midland (ADM), Bunge, Cargill and Louis Dreyfus Company (the ‘ABCD’ firms). The activities of the ABCD firms typically involve extensive cross-border trade and investment, which define internationalisation at a grand scale. The similarities in strategy and approaches of ABCD firms from an internationalisation perspective can be interpreted as a “convergence in practice” in the global agro-food system. However, the virtual absence of the ABCD firms in sub-Saharan Africa means that the continent remains the last frontier of global agro-food system convergence. In this sense, emerging agribusiness MNCs in sub-Saharan Africa represent a harbinger of global convergence in the continent’s agro-food sector. Yet there is limited understanding of the activities, strategies and approaches of these agribusiness MNCs. The objective of the study is to unpack agro-food system convergence within the context of agribusiness internationalization in sub-Saharan Africa. This task is achieved in four ways. First, the study shows evidence of convergence in sub-Saharan Africa through a trend analysis of four agribusiness MNCs within the continent. The analysis identifies similarities in strategy and approach between agribusiness MNCs in sub-Saharan Africa and ABCD firms. Second, the study assesses the cross-border market entry behavior of 67 agribusiness firms in the continent, including the four aforementioned firms that were used to illustrate evidence of convergence. Third, the study assesses the transboundary alliance behavior of 10 firms drawn from the same sample to show evidence of “corporate clustering” or cluster convergence. Fourth, the study takes a closer look into firm-level behavior through a specific case study of an internationalising agribusiness MNC in Zambia to show evidence of supplier convergence. Several research methods were used to analyse the various dimensions of convergence, all of which were examined within the framework agribusiness internationalisation. These methods include trend analyses to identify strategies and approaches, a multinomial logit model to assess cross-border entry strategies, game theory to assess the likelihood of transboundary strategic alliances and cluster convergence, and system dynamics modelling to analyse value chain integration and supplier convergence. The respective research methods were applied to a variable number of agribusiness firms which were drawn from the same sample. The study found evidence of convergence – defined by a gravitation of the agro-food system towards fewer large-sized agribusiness MNCs – which is being driven by two growth phenomena, namely, growth through value chain integration and growth through strategic alliances. The study identified these two types of convergence as follows: a) Supplier (?) convergence, which occurs when firms seek to gain competitive advantage in new markets by internalising critical but non-core value chain functions; and b) Cluster (?) convergence, which occurs when agribusiness MNCs leverage complementary assets of other competing firms and use collaborative advantage as a means to gain competitive advantage in new markets. The analysis predicts that there will be “a collapse of the middle”, which is defined by a gradual disappearance of agribusiness firms with an annual turnover ranging between US$160 million and US$996 million per annum, most of whom will enter into strategic alliances. Such strategic alliances are leading to a formation of large clusters that will likely morph into multi-billion-dollar agribusiness firms. It is entirely possible that these mega-agribusiness MNCs can ultimately be acquired by the powerful quartet of ABCD firms once the sub-Saharan African market matures, a phenomenon that will complete the final phase of global agro-food convergence.Thesis (PhD)--University of Pretoria, 2018.
Agricultural Economics, Extension and Rural Development
PhD
Unrestricted
21
Mainga, Alfred Omwando. "Occurrence and characterisation of the seven major Shiga toxin-producing Escherichia coli serotypes from healthy beef cattle in South Africa." Diss., University of Pretoria, 2017. http://hdl.handle.net/2263/65499.
Abstract:
Shiga toxin-producing E. coli (STEC) is a food pathogen causing infections characterised by mild watery to severe bloody diarrhea and complications such as the hemolytic uremic syndrome (HUS). Humans acquire STEC through consumption of contaminated foods of animal origin, vegetables and water. Cattle are the main reservoir of STEC. The severity of STEC infections in humans depends on a number of virulence factors encoded in the bacterium’s genome. The seven major STEC serogroups most frequently incriminated in severe human disease outbreaks and HUS worldwide include O157, O45, O103, O111, O121, O145 and, O26, commonly referred to as the "top/big seven". Although STEC has been incriminated in human disease in South Africa, data on the role of played by cattle in human disease and virulence characteristics of cattle STEC are lacking. Therefore, the objectives of this study were to (i) investigate the presence of the seven major STEC serotypes in healthy beef cattle (cow-calf operations) and (ii) characterise isolates by serotype, virulence genes and markers, and antimicrobial resistance profiles. Polymerase chain reaction (PCR) was carried out to identify STEC serotypes (O and H antigens) and characterize the isolates by virulence factors and markers. The disk diffusion technique (Kirby Bauer test) was used to determine the antimicrobial resistance profiles of STEC isolates against a panel of 15 antimicrobials. Five hundred and seventy-eight STEC isolates (N=578), which had been previously recovered from 559 cattle from five beef farms were screened for STEC O26, O45, O103, O111, O121, O145 and O157. Confirmed STEC belonging to serogroups O26, O45, O103, O111, O121, O145 and O157 to isolates were characterised for major virulence genes including stx1, stx2, eaeA and ehxA. Furthermore, 140 isolates were characterised for xiii Shiga toxins (stx) subtypes, plasmid and pathogenicity island-encoded genes, and antimicrobials resistance profiles.Dissertation (MSc)--University of Pretoria, 2017.
Paraclinical Sciences
MSc
Unrestricted
22
Takahashi, Ryan. "Structured Matrices and the Algebra of Displacement Operators." Scholarship @ Claremont, 2013. http://scholarship.claremont.edu/hmc_theses/45.
Abstract:
Matrix calculations underlie countless problems in science, mathematics, and engineering. When the involved matrices are highly structured, displacement operators can be used to accelerate fundamental operations such as matrix-vector multiplication. In this thesis, we provide an introduction to the theory of displacement operators and study the interplay between displacement and natural matrix constructions involving direct sums, Kronecker products, and blocking. We also investigate the algebraic behavior of displacement operators, developing results about invertibility and kernels.
23
Albajar, Viñas Ferran. "Radiation Transport Modelling in a Tokomak Plasma: Application to Performance Prediciton and Design of Future Machines." Doctoral thesis, Universitat Politècnica de Catalunya, 2001. http://hdl.handle.net/10803/6599.
Abstract:
The understanding and modelling of heat and radiation transport in tokamak plasmas is essential in order to progress in the development of thermonuclear fusion towards a practical energy source which meets all the future needs of environment, safety, and fuel inexhaustibility. This activity enables prospective studies and design to be carried out for next step tokamaks. Due to the complexity of the exact calculation, synchrotron losses are usually estimated in such studies, with expressions derived from a plasma description using simplifying assumptions on the geometry, radiation absorption, density and temperature profiles. In this thesis, a complete formulation of the transport of synchrotron radiation is performed for realistic conditions of toroidal plasma geometry with elongated cross-section, using a precise method for the calculation of the absorption coefficients, and for arbitrary shapes of density and temperature profiles. In particular, this formulation is able to describe plasmas with arbitrary aspect ratios and with temperature profiles obtained in internal transport barrier regimes, which cannot be described accurately with the present expressions. As an illustration, we show that in the case of an advanced high-temperature plasma envisaged for a steady state D-T commercial reactor, synchrotron losses represent approximately 20% of the total losses. Considering the quantitative importance of the above effects and the significant magnitude of synchrotron losses in the thermal power balance of a D-T tokamak reactor plasma, a new fit for the fast calculation of the synchrotron radiation loss is proposed. Using this improved model in the thermal balance, prospective and sensitivity studies are performed for future tokamak projects, and the key issues which limit the performance are isolated. It is shown that, the most restrictive constraint for achieving higher plasma performance is the peak heat flux on the divertor plates. In non-inductive steady-state operation, advanced tokamak regimes are required to achieve relevant thermonuclear plasma performance for next step tokamaks and for a commercial reactor. In the frame of a multi-step strategy towards a commercial reactor, a superconducting next step tokamak compatible with the European budget possibilities is optimized. Considering both the plasma physics and the magnetic system technology and for a given aspect ratio, the smallest machine meeting the physical and technological requirements is determined. In a steady state tokamak commercial reactor, we show that there is an optimal value for the confinement enhancement factor which maximizes the plasma performance, for a given and also for the highest electrical power into the network. This highest electrical power meeting the stability requirements steadily decreases with the confinement enhancement factor. This effect is crucial because both a high plasma performance and a high enough electrical power into the network are required to minimize the cost of electricity, and consequently to make fusion energy more competitive.
24
Kindervater, Garnet. "Human with non-human digital surveillance and the integrated network(s) of urban space /." Connect to resource, 2006. http://hdl.handle.net/1811/6599.
Abstract:
Thesis (Honors)--Ohio State University, 2006.Title from first page of PDF file. Document formatted into pages: contains 39 p. Includes bibliographical references (p. 37-39). Available online via Ohio State University's Knowledge Bank.
25
Gerhardt, Frederik C. "Unsteady aerodynamics of upwind-sailing and tacking." Thesis, University of Auckland, 2011. http://hdl.handle.net/2292/6599.
Abstract:
Predicting unsteady sailing yacht performance is of significant current interest to racing syndicates and yacht designers alike because it is anticipated that optimising boats for dynamic conditions will lead to large performance gains. Such optimisations are usually carried out with the aid of Dynamic Velocity Prediction Programs (DVPPs). These programs require knowledge about the behaviour of the sails in unsteady flow. To this end Part A of this work looks at the simplified unsteady aerodynamics of a yacht that sails upwind in waves. Unsteady thin aerofoil theory is extended to the case of two interacting aerofoils representing the headsail and mainsail. The developed novel method is analytical in nature and is based on representing the sail bound vorticity distributions and the unsteady vortex wakes by planar vortex sheets. The theory is successfully validated against data from the literature and pressure distributions from wind tunnel tests. An application of the theory to the case of an International America's Cup Class yacht that pitches in waves reveals that the time-varying components of the aerodynamic forces are small and that only very little energy can be extracted from the unsteady flow about the sails and converted into thrust. Part B looks at the aerodynamics of a yacht that tacks. Since today's DVPPs usually suffer from a lack of available data on the behaviour of the sail forces at very low apparent wind angles a series of quasi-steady experiments was carried out. Test results for different tacking scenarios (headsail flogging or backed) are presented in a form that facilitates incorporation into a DVPP. The quasi-steady approach used in the wind tunnel tests does not account for unsteady effects like the aerodynamic inertia due to the 'added mass' of the sails. The added inertia of a sail can, however, be estimated by 'strip theory'. Using expressions from the literature and experimental results it is found that such a strip theory over-estimates the added inertia of a mainsail by about 20% because it neglects the three-dimensional flow around the head and the foot of the sails. Using the DVPP FS Equilibrium the influence of added sail inertia on the tacking behaviour of a yacht is studied and it is found that added sail inertia has a small but noticeable influence on tacking performance.
26
Pires, Esmeralda Cristina Nunes. "O feminino e o masculino nos manuais escolares do 1.º ciclo do ensino básico. A opinião das professoras e dos professores de dois agrupamentos de escolas do Norte Alentejano." Master's thesis, Instituto Politécnico de Portalegre - Escola Superior de Educação, 2014. http://hdl.handle.net/10400.26/6599.
Abstract:
Atendendo à necessidade de desenvolver um currículo que propicie aprendizagens em diferentes áreas curriculares numa perspetiva de formação integral do e da aluna, a educação para a cidadania e, em particular, a educação/formação para a igualdade de oportunidades de género, toma particular importância nos primeiros anos de escolaridade.
No desenvolvimento desta dissertação procurou-se a participação ativa das professoras e dos professores do 1.º ciclo do Ensino Básico, recolhendo e interpretando as suas opiniões sobre a importância de educar/formar para a identidade e igualdade de género na escola do 1.º ciclo do Ensino Básico.
Dado que os materiais, com destaque para os manuais escolares, assumem particular importância no processo de ensino e de aprendizagem, assume-se que existam critérios rigorosos na sua seleção e na sua escolha, em particular no que às oportunidades para a igualdade de género diz respeito. Atendendo a esta necessidade, estarão as professoras e os professores do 1.º ciclo do Ensino Básico conscientes de que os manuais escolares podem ser veículos de estereótipos sociais que contribuem negativamente para a vivência da igualdade de oportunidades entre o género masculino e o género feminino?
A investigação realizada nesta dissertação demonstra que a escolha dos manuais escolares ainda não tem, de forma consciente e deliberada, preocupações com as mensagens textuais e figurativas em função da igualdade de oportunidades entre homens e mulheres, pelo que se assume a urgência e a necessidade de (re)configurar a escolha dos manuais escolares e das práticas curriculares na escola do 1.º ciclo do Ensino Básico.Given the need to develop a curriculum that enables learning in different curricular areas, in a perspective of a comprehensive training of the male and female students, the citizenship education and, particularly, the education/ training for equal opportunities between genders, assumes an important role in the first school years. Throughout the development of this thesis we looked for the active participation of male and female teachers from Elementary Schools, gathering and interpreting their issues regarding the importance of educating/ training for the identity and equality of gender in Elementary Schools. Given that the materials, mainly the schools textbooks, assume a considerable importance in the process of teaching and learning, it was expected that rigorous criteria were used in their selection and choice, particularly regarding the opportunities for gender equality. Bearing in mind this need, are male and female teachers of Elementary Schools aware that school textbooks can convey social stereotypes that contribute negatively to the equality of opportunities between the male gender and the female gender? The investigation undertaken throughout this thesis reveals that the choice of schools textbooks still doesn’t contain, in a conscious and deliberate way, concerns regarding textual and figurative messages about the equality of opportunities between men and women, thus allowing us to alert for the urgency and need to reconfigure the choice of school textbooks and curricular practices in Elementary Schools.
27
Zaabab, Abdel Hafid. "SCFL VLSI circuits for improved yield." Thesis, University of Ottawa (Canada), 1993. http://hdl.handle.net/10393/6599.
Abstract:
In this thesis an improvement to the Gallium Arsenide source coupled FET logic ECL output cell is presented. Because of parameter variations from site-to-site in the wafer, ECL compatibility of source coupled FET logic circuits, in terms of voltage levels and clock duty cycle, was very poor and therefore the electrical yield was very low. A source coupled FET logic buffer driver was designed to make the Gallium Arsenide ECL cell more resistant to parameter variations and consequently, the yield is highly improved. Furthermore, multi-site circuits are now possible with a high output electrical yield. The circuit complexity is limited by the latency problem which occurs when using both high and low frequency signals to drive the gate. In this research, the latency time period is reduced by over 75% and hence either the operating frequency or the complexity can be increased six times.
28
De, Sassi Claudio. "Biotic interactions in a changing world: the role of feeding interactions in the response of multitrophic communities to rising temperature and nitrogen deposition." Thesis, University of Canterbury. School of Biological Sciences, 2012. http://hdl.handle.net/10092/6599.
Abstract:
Global warming and increasing atmospheric nitrogen deposition are ranked as second and third most important global drivers of biodiversity loss. Widespread species losses have deep implications for the functioning of ecosystems, the delivery of essential ecosystem services and their resilience to future environmental perturbations.
There is growing recognition that interactions between species play a crucial role in determining the response of ecosystems to global environmental changes. Moreover, evidence of synergistic effects between global change drivers has prompted numerous calls to integrate multiple drivers in ecological research. Nevertheless, empirical studies assessing the impacts of temperature and nitrogen on communities at multiple trophic levels are largely absent. This thesis explores the effects of temperature and nitrogen on a tri-trophic system comprising plants, herbivores and natural enemies. The first chapter shows impacts of the drivers on the composition and phenology of an herbivore community. The second chapter highlights changes in biomass under the treatments at three trophic levels. The third chapter explores, for the first time, the impacts of temperature and nitrogen on quantitative food webs. Finally, the last data chapter uses body size as an important species trait to gain insights on the mechanisms causing shifts in food web structure.
The key findings of this thesis were i) trophic interactions largely mediated the effects of both global change drivers ii) In particular, strong bottom-up effects determined the system response, with herbivores responding positively and consistently more so than plants and parasitoids in particular. However, iii) this contrasting response was not explained by a phenological mismatch. iv) Food-web structure responded to the changes in composition of herbivores and parasitoids, but shifts in interaction structure did not affect the resilience of the food. However, temperature and nitrogen impacted host-parasitoid food-web structure by altering the response of parasitoid species to host density and size structuring, which is likely to bear consequences on host-parasitoid co-evolution and future food-web architecture and stability. Finally, v) we found frequent, non-additive interactions between the global change drivers. We conclude that co-occurring temperature and nitrogen are likely to alter food-web structure and overall ecosystem balance, with increasing herbivore dominance likely to have important implications for ecosystem functioning and food-web persistence.
29
Renaud-Deputter, Simon. "Système de recommandations utilisant une combinaison de filtrage collaboratif et de segmentation pour des données implicites." Mémoire, Université de Sherbrooke, 2013. http://hdl.handle.net/11143/6599.
Abstract:
Avec la montée de la technologie et la facilité d'accès à Internet, les utilisateurs sont submergés par un large éventail de choix disponibles et une quantité considérable d'informations [6]. Il devient nécessaire d'avoir accès à des outils et des techniques efficaces pour filtrer les données et de les rendre utilisables pour des opérations de tous les jours. À cette fin, des systèmes de recommandations, qui ont fait l'objet de recherche active et de développement au cours des 15 dernières années, sont maintenant capables de fournir aux utilisateurs des choix [51] sur ce qu'ils aimeraient lire, acheter, regarder, manger, etc. La problématique étudiée dans ce mémoire est l'utilisation d'informations implicites pour construire des systèmes de recommandations en utilisant une approche par filtrage collaboratif. Beaucoup de travaux ont été faits sur l'utilisation de filtrage collaboratif à l'aide d'informations explicites telles que les cotes [48], [43], [19], [33]. Cependant, les techniques développées pour les systèmes de recommandations comprenant des articles sans informations explicites restent rudimentaires. Le plus grand défi vis-à-vis les systèmes de recommandations à informations implicites est l'absence de rétroaction de la part de l'utilisateur si nous n'utilisons pas un expert comme par exemple, un vendeur. En outre, comme il est mentionné dans [51], lorsque qu'un système avec cote existe, la proportion des éléments évalués est souvent inférieure à 1%. Par conséquent, même pour les systèmes de recommandations qui utilisent des informations explicites telles que les cotes, il est crucial d'avoir une méthode qui tire profit des informations implicites. Les progrès dans ce domaine sont timides depuis les dernières années. Il y a eu des études sur les recommandations par rapport aux médias sociaux en se basant sur des utilisateurs et des mots-clés [18], la modélisation probabiliste [30] et la modélisation sémantique basée sur la recommandation de nouvelles [29]. S'il est vrai que ces techniques utilisent des informations implicites, seuls quelques-uns [40], [23] abordent la question de recommander des produits d'un magasin sans l'utilisation d'informations explicites. Ces méthodes nécessitent généralement la disponibilité d'un expert afin de prendre la rétroaction d'un client ou le réglage de nombreux paramètres. Dans notre étude, nous avons réussi à élaborer un algorithme permettant de soumettre des recommandations personnelles à un utilisateur en utilisant seulement des informations implicites. Notre technique, lorsque comparée à un système semblable qui utiliserait des cotes comme informations explicites, génère de très bons résultats. De plus, lorsque la méthode développée est comparée à d'autres systèmes utilisant de l'information implicite, elle offr des résultats qui sont comparables et parfois supérieurs à ceux-ci.
30
Delin, Judith Lesley. "Cleft constructions in discourse." Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/6599.
Abstract:
This thesis presents an analysis of the structure and function of cleft constructions in discourse. Drawing on a corpus of naturally-occurring spoken and written data, we present a multi-layered explanation of how it-clefts, wh-clefts, and reverse wh-clefts are different from non-clefts, and from one another. After a review of previous research on clefts in discourse, we explore the aspects of syntax, semantics, and pragmatics relevant to the structure and function of all three types of cleft. The discussion falls into three main parts: An analysis of the three cleft types, within the framework of Generalized Phrase Structure Grammar (cf. Gazdar et al. [1985]), in which particular attention is paid to the variety of constituents that can appear in particular positions in each type. The output of the grammar rules is compared to the examples that occur in the corpus of data. A treatment of cleft presupposition in terms of an analogy (suggested by van der Sandt [1988]) between presupposition and the treatment of pronominal anaphora in Kamp's [1981] Discourse Representation Theory An examination of the range of accentual patterns, presuppositional relations, and information structures typically appearing in clefts of all three kinds. We show that marked distinctions exist between the three cleft types in terms of all these factors, and suggest ways in which this helps to differentiate the range of discourse contexts in which clefts in general, and each cleft type in particular, are appropriate. At the end of the thesis we point to an analogy between the formal model for clefts presented and a psychological model of sentence processing We also suggest how the conclusions regarding both the structure and function of clefts as a class of construction and the distinction between the three types of cleft could be synthesised in a decision procedure for syntactic choice. Finally, we suggest some related areas for further research.
31
Williams, Samantha. "Perceptions of wetland ecosystem services in a region of climatic variability." University of the Western Cape, 2018. http://hdl.handle.net/11394/6599.
Abstract:
Magister Artium - MAWetlands provide various ecosystem services such as provisioning, regulating, supporting, and cultural services which may be directly or indirectly beneficial to humans. The manner in which such wetlands are managed is partly determined by human perceptions of their value. However, climatic variability and climate change put the continued provision of such ecosystems under stress. The result is that certain ecosystem services may be provided to differing extents during anomalously wet or dry years. There is thus uncertainty as to the values ascribed to wetlands by people during varying climatic phases. This thesis focuses on understanding how people perceive the functioning of wetlands within our current climate against a background of climatic variability and climate change. This study explores people’s perceptions regarding the functioning of wetlands and ecosystem services provided during dry and wet years, as an indication of how climatic variability and climate change impact peoples’ perceptions. The data was collected in the wetlands of the Agulhas Plain in the Nuwejaars Catchment. Five wetlands classified and scored using the WETEcoServices tool. In addition, five semi-structured interviews and three participatory mapping exercises with landowners were also undertaken. The study reports on the landowners’ awareness of wetland ecosystems, ecosystem services and climatic variability and climate change. Provisioning, supporting, and cultural ecosystem services are frequently used by landowners, which can be impacted by climatic variability and climate change. The WETEcoService benefits and landowners perceptions of ecosystem services varies, as the WETEcoService direct and indirect ecosystem services are either effective or ineffective in dry and wet years. In contrast to landowners perceptions emphasising the importance of ecosystem services directly beneficial to them. The study recommends that the ecosystem services landowners perceive as important is linked to their interest to guarantee their participation in catchment management. WET-EcoService benefits can inform landowners and managers about ecosystem services degradation and whether their conservation methods are either positively or negatively impacting wetlands.
32
Wranz, Elsie Sophia. "Compulsory community service for speech-language and hearing therapy professionals : readiness, reality and readjustment." Thesis, Stellenbosch : University of Stellenbosch, 2011. http://hdl.handle.net/10019.1/6599.
Abstract:
Thesis (MPhill)--University of Stellenbosch, 2011.ENGLISH ABSTRACT: Compulsory Community Service for the speech-language and hearing therapy profession was implemented in 2003. This is the first study to assess the perceptions, attitudes and experiences of speech-language and hearing professionals of Stellenbosch University doing Compulsory Community Service. Information on the experiences of Compulsory Community Service professionals inform on the responsibilities of the university where undergraduate studies are completed, the Department of Health (the employer) and professionals doing Community Service. A mixed method study design, using a scale questionnaire, supplemented by open-ended questions was completed by all but one of the group doing Compulsory Community Service in 2009. Results suggested that speechlanguage and hearing therapists perceived themselves to have the required knowledge, but not necessarily adequate skills to perform Compulsory Community Service. Suggestions to include additional curriculum content were made. All professionals agreed that a positive contribution was made during Compulsory Community Service, but concerns about the shortage of speech-language and hearing therapy services, absence of mentors and supervision, inadequate budgets, amenities and resources were identified. Readjustment must involve adaptation from all stakeholders to ensure that Compulsory Community Service honours its original objectives.
33
Teixeira, Alfredo. "Reparto de la grasa en función de la condición corporal (Body Condition) en ovejas adultas Rasa Aragonesa." Master's thesis, Instituto Agronomico Mediterraneo de Zaragoza, 1987. http://hdl.handle.net/10198/6599.
Abstract:
Las relaciones entre los diferentes depósitos grasos y la
nota atribuida a la condición corporal (C . C. ) fueron
determinadas en 52 ovejas adultas ( 10 + 2 años) de raza
Aragonesa distribuidas en 13 grupos de 4 ovejas con C.C . en
el rango de 1,5 4 , 5 . La C. C. de cada oveja fue evaluada
por 3 jueces verificándose una respetabilidad del 80% entre
jueces y de l 90% dentro de cada juez . A su vez l a cantidad
de grasa depositada a l rededor de la cola fue evaluada según
una escala de 3 puntos . Las ovejas fueron pesadas antes del
sacrificio . Des pues de sacrificadas se separaron l os
depósitos de grasa omental, mesentérica y pélvica + renal .
Se procedió a la disecci6n de la media cana l izquierda, para
la obtención de los depósitos de grasa subcutánea e
intermuscular. La zona de palpaci6n donde se evalúa la C. C. ,
denominada "cuadrado lumbar" fue diseccionada en sus
componentes : músculo , grasa sub cutánea , grasa intermuscular
y hueso.
34
Ballena, Santos Oscar Alexis. "Propuesta de manual de buenas prácticas de manufactura aplicable a dispositivos médicos implantables hechos a medida fabricados por impresión 3D." Bachelor's thesis, Universidad Nacional Mayor de San Marcos, 2017. https://hdl.handle.net/20.500.12672/6599.
Abstract:
Aborda una nueva tendencia en la industria de los dispositivos médicos la cual está en gran expansión actualmente debido a sus múltiples aplicaciones y ventajas pero sin alguna normativa peruana que pueda cubrir apropiadamente los aspectos críticos propios de esta tecnología. Esta propuesta de manual de buenas prácticas de manufactura tiene por finalidad proporcionar requisitos para su implementación en el sistema de aseguramiento de calidad de laboratorios y centros médicos. Estos requisitos son generados a partir de consideraciones técnicas que surgen en las etapas de diseño y fabricación por impresión 3D de dispositivos médicos implantables hechos a medida, los cuales son los más críticos en materia de riesgo.Tesis
35
Vijay, Sianne Diana. "The Impact of Criminal Justice Interventions and Social Policies on Family Violence: Theory and Evidence." Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6599.
Abstract:
In 2014, the Child Protective Services received 3.6 million referrals alleging child abuse and neglect, of which, 702,000 children were victims of abuse and neglect and an estimated 1,580 children died due to maltreatment. In addition to this appalling toll, the welfare effects of child victimization are substantial. Evidence suggests that compared to demographically similar adults who were non-victims, adults with documented histories of maltreatment are more likely to engage in criminal behavior; have adverse mental and physical health problems such as depression, addiction and post-traumatic stress disorder; and have lower levels of education and earnings. These essays contribute toward the understanding of the consequences of two very distinctive policies – mandatory arrest and medical marijuana laws – and their impact on child maltreatment.
An important and controversial question in criminal justice policy concerns whether aggressive sanctions, such as mandatory arrest policies, serve as effective deterrents to familial violence. Chapter 1 provides a theoretical framework that models child abuse in which I allow for a strategic interaction between the child and his or her abuser. The comparative statics yield clear predictions of the impact of sanctions on child maltreatment – as the cost and probability of external interventions rise, the probability of violence falls. I follow this theoretical analysis with an empirical investigation of the impact of mandatory arrest policies on child victimization. I find a statistically significant and positive relationship between states that have implemented mandatory arrest laws and reported child maltreatment rates. This may seem surprising; however there are two explanations for the results. The likely explanation is that reporting of maltreatment increased in states mandating arrest; alternatively, recidivism may have increased in these states. Evidence from the OLS estimates for the reporting of abuse and child fatality rates (a proxy for the true incidence of child abuse), demonstrates that the increase in maltreatment is not due to recidivism but, in fact, more people reporting abuse to the police and Child Protective Services. The most important result that emerges from the data, however, is that while reported abuse increases in states with mandatory arrest laws, the true incidence of maltreatment actually falls. The ultimate goal of this paper is to stimulate further theoretical and empirical research that focuses on child abuse and prevention, thus enhancing an understanding of how sanctions influence child victimization.
The next chapter looks at one potential risk factor for child maltreatment –marijuana use and liberalization –using evidence from medical marijuana laws (MMLs). Chapter 2 begins by extending the current MML-crime literature by providing a comprehensive evaluation of the impact of MMLs implemented at the state level on reported child victimization rates. I show that specific modes of medical marijuana regulation differentially influence the magnitude of reported incidences of child abuse, a finding which sheds new light on the current literature. More specifically, using fixed effects analysis applied to data from the National Child Abuse and Neglect Database System (NCANDS) and the Uniform Crime Reports (UCR), I show that states that allow for home cultivation in addition to decriminalizing its use see a further increase in the magnitude of reported incidences of child maltreatment rates.
Since completing my dissertation, I have continued to investigate into issues that have implications for both theory and practice in my field. To that extent, I plan to analyze the slowly developing public sphere –a platform where culture and social change rely on both media and conversation.
36
Daines, Maria Matthews. "The influence of environment on severe obesity /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6599.
37
Imler, Henry DesRosiers Nathaniel. "Husbands scorned and fathers ignored a social analysis of the Acts of Thomas /." Diss., Columbia, Mo. : University of Missouri--Columbia, 2009. http://hdl.handle.net/10355/6599.
Abstract:
Title from PDF of title page (University of Missouri--Columbia, viewed on Feb 18, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Thesis advisor: Dr. Nathaniel DesRosiers. Includes bibliographical references.
38
Wilcox, Matthew Porter. "Evidence for the Validity of the Student Risk Screening Scale in Middle School: A Multilevel Confirmatory Factor Analysis." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/6599.
Abstract:
The Student Risk Screening Scale—Internalizing/Externalizing (SRSS-IE) was developed to screen elementary-aged students for Emotional and Behavioral Disorders (EBD). Its use has been extended to middle schools with little evidence that it measures the same constructs as in elementary schools. Scores of a middle school population from the SRSS-IE are analyzed with Multilevel Confirmatory Factor Analysis (MCFA) to examine its factor structure, factorial invariance between females and males, and its reliability. Several MCFA models are specified, and compared, with two retained for further analysis. The first model is a single-level model with chi-square and standard errors adjusted for the clustered nature of the data. The second model is a two-level model. Both support the hypothesized structure found in elementary populations of two factors (Externalizing and Internalizing). All items load on only one factor except Peer Rejection, which loads on both. Reliability is estimated for both models using several methods, which result in reliability coefficients ranging between .89-.98. Both models also show evidence of Configural, Metric, and Scalar invariance between females and males. While more research is needed to provide other kinds of evidence of validity in middle school populations, results from this study indicate that the SRSS-IE is an effective screening tool for EBD.
39
Callahan, Karin E. "Validation of a Radiometric Normalization Procedure for Satellite-Derived Imagery Within a Change Detection Framework." DigitalCommons@USU, 2003. https://digitalcommons.usu.edu/etd/6599.
Abstract:
Detecting changes in land cover through time using remotely sensed imagery is a powerful application that has seen increased use as imagery has become more widely available and inexpensive. Before a time series of remotely sensed imagery can be used for change detection, images must first be standardized for effects outside of real surface change. This thesis established a validation protocol to evaluate the effectiveness of an automated technique for normalizing temporally separate but spatially coincident imagery. Using the concept of pseudo-invariant features between master-slave image pairs, spatially coincident dark and bright points are identified from images and a regression equation is calculated to normalize slave images to a master. I used two sets of imagery to test the performance of the standardization process, a spatially coincident, but temporally variable time series, and spatially and temporally variable images. I tested the underlying statistical assumptions of this approach, and performed simple image subtraction to validate the reduction of master-slave differences using invariant locations. In addition I tested the possibility of reducing between-sensor differences by applying simple linear regression to comparable bands of MSS and TM sensors.
Image subtraction showed decreases in master-slave differences as a result of the standardization process, and the process behaved appropriately when there should be no difference between master and slave images (adjacent, but temporally identical imagery). I also found that comparable bands between MSS and TM sensors are similar enough that linear regression may not significantly reduce between-sensor differences.
40
Lang, Kenneth. "Valuation of Ex-Offender Motivation for Participation in a Restorative Justice Praxis." ScholarWorks, 2019. https://scholarworks.waldenu.edu/dissertations/6599.
Abstract:
Restorative justice (RJ) is an emerging concept of justice in the American penal system that seeks equality for all stakeholders involved. While RJ is vastly under researched--especially concerning RJ and violent offenses--current studies have only focused on determining victims' motivations for participating in RJ. Determining and evaluating offender motivations for participating in RJ remains unexplored. The purpose of this study was to explore the possible motivations of criminal offenders and their willingness to participate in RJ. The social construction framework and the narrative policy framework were employed to understand the social context. A mixed-method approach was used that began with a semistructured interview of 12 ex-offenders and concluded with all the participants completing a brief questionnaire capturing their demographical information. Participants were previously convicted criminal offenders (i.e., 7 nonviolent and 5 violent) who were no longer under the authority of the judiciary system. The semistructured interviews were analyzed qualitatively and identified six motivations: (a) concern for their reputation, (b) understanding the impact of their crime, (c) explanation of actions, (d) making the victim whole, (e) apologizing to the victim, and (f) apathy towards the victim. MANOVA analysis revealed no significance difference between the groups, except with Motive 3 (explanation of actions) and whether the participant had siblings. However, observed power for this analysis varied at low intervals where only 12 participants were involved. Regardless, the results of this study could have a significant impact on positive social change in RJ because the data informs practitioners how to facilitate RJ interventions better, bringing about efficacy with offenders.
41
King, Benjamin Michael. "Interactions of environmental and therapeutic particles with the airway microenvironment." Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6599.
Abstract:
Particles that deposit in the respiratory airways can come from many sources, such as environmental pollution, particles created in the workplace, and inhalers that are designed to deliver medicines to the lungs. Once these particles deposit in the respiratory airways, they can interact in a variety of ways. Some particles are toxic and can cause damage to lung tissues, others may have little to no effect on health, and some may provide some benefit or therapy. Once particles land in the respiratory airways, the interactions they have with proteins can impact where they go and how they behave.
This thesis explores how particles that are inhaled may impact health through toxicity to lung cells. Aerosols produced from photooxidation of decamethylcyclopenta-siloxane, an ingredient common in personal care products, were exposed to lung cells using an air-liquid interface exposure system to assess if these aerosols impact lung cell health. No significant impacts on lung cell health were observed. Copper oxide, a component of cigarette smoke, urban particulate matter, and e-cigarette vapor, was assessed for its role in lung disease. Copper oxide nanoparticles were exposed to lung cells, and their viability, expression of a platelet activating factor receptor (PAFR), and susceptibility to infection with a pneumonia-causing bacterium (S. pneumoniae) were measured. Copper oxide nanoparticles were found to be toxic to lung cells. At some doses, increases in PAFR were observed, but no clear differences in susceptibility to bacterial infection were observed. This research improves knowledge of how inhaled materials can impact health, providing insight into how particles from human-derived sources affect the lungs.
This thesis further explores how particles behave in the thin layer of fluid that covers the respiratory epithelium. This fluid contains a complex mixture of proteins, and this work aims to identify some of the ways these proteins interact with particles and influence behavior. This was accomplished by first investigating how individual proteins from this fluid interact with particles. Particle behavior was studied after exposure to these proteins, as well as the lung cell responses to the particles before and after interaction with individual proteins. These lung proteins were found to induce aggregation, significantly alter surface charge, and reduce cell uptake of particles. After studying how individual proteins might specifically affect particle behavior, particles were exposed to bronchoalveolar lavage fluid (BALF), a diluted lung fluid collected by rinsing lungs with saline. Particle responses to proteins in this fluid were compared to those in serum, a protein-rich blood extract. These studies identified differences in how various surface-functionalized polystyrene particles aggregated in BALF compared to serum. When particles were exposed to serum or BALF, they tended to be less likely to associate with lung cells. With some particle types studied, there were significant differences in how much BALF or serum reduced cell attachment and uptake. In addition to demonstrating that lung fluids impact particle behavior in a manner that differs from serum, a method was developed to increase the concentration of the proteins in BALF to partially undo the dilution that occurs during collection. After studying how protein adsorption can cause aggregation, cover up particle surfaces, and reduce attachment and uptake by lung cells, a polymer coating was synthesized to reduce particle interactions with these proteins and assist in stabilizing particles in lung fluids. This coating was tested in both BALF and serum to demonstrate its general utility at reducing undesired interactions with proteins in biological fluids and was found to enhance particle stability in lung fluids as well as saline. This research enhances understanding of how particles behave in the respiratory airways, providing tools to further study how particles behave in lung fluids and demonstrating a polymer coating that is useful in this environment.
42
Russo, Olga <1988>. "Genealogia della danza femminile in Giappone: dalle origini all'Okuni kabuki." Master's Degree Thesis, Università Ca' Foscari Venezia, 2015. http://hdl.handle.net/10579/6599.
Abstract:
La mia tesi vuole mettere in risalto il percorso della danza femminile in Giappone dalle origini al kabuki di Okuni. Il mio lavoro è eseguito attraverso la lettura critica di testi di letteratura e teatro giapponese e di studi internazionali.
43
Alwhshe, Brnyia Omar Salem. "Synthesis and applications of nanostructured metal oxide films." Thesis, University of Sussex, 2016. http://sro.sussex.ac.uk/id/eprint/65099/.
44
Волохін, Віталій Васильович, Виталий Васильевич Волохин, Vitalii Vasylovych Volokhin, В. С. Гаврилюк, and С. П. Гришко. "Портативний індукційний нагрівач." Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65599.
Abstract:
Теоретичні основи техніки індукційного нагріву були закладені ще в минулому столітті, на сучасному етапі в промисловості метод індукційного нагріву стає все більше й більше використовуваним. Він слугує для чистого безконтактного плавлення, спаювання і зварювання металу, згину та термообробки деталей машин і дрібних деталей, які можуть пошкодитись при газовому чи дуговому зварюванні, поверхневого загартування й термообробки деталей складної форми, ювелірної справи, знежирення медичних інструментів.
45
Мозговий, Іван Павлович, Иван Павлович Мозговый, Ivan Pavlovych Mozghovyi, Алла Олександрівна Васюріна, Алла Александровна Васюрина, and Alla Oleksandrivna Vasiurina. "Наука на початку ІІІ тисячоліття і моральна відповідальність вченого перед майбутнім." Thesis, Сумський державний університет, 2012. http://essuir.sumdu.edu.ua/handle/123456789/65199.
Abstract:
На початку III тисячоліття населення Землі стає свідком вражаючих
успіхів науки. Її вплив на людське співтовариство настільки переконливий і
грандіозний, що його, здавалося б, не можна піддавати сумніву. Але,
незважаючи на це, людство в особі представників науки і широких
пересічних мас нерідко з великою тривогою і стурбованістю дивиться в своє
майбутнє. Світ нині став надто небезпечний для життя людини: локальні
війни, терористичні акти, найбільш витончені форми вбивств, що знижують
цінність людського життя, – ось що постає сьогодні перед нами, викликаючи
почуття страху за майбутнє наших дітей і онуків.
46
Грицун, Д. В., Віталій Іович Симоновський, Виталий Иович Симоновский, and Vitalii Iovych Symonovskyi. "Исследование особенностей динамики ротора турбокомпрессора ГПА." Thesis, Сумский государственный университет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65099.
Abstract:
В работе исследованы особенности динамики ротора ГПА, связанные с
неконсервативными составляющими реакций сегментных подшипников, а также
нелинейностями квазиупругих сил. Расчёты проведены на основе нелинейной
дискретной модели, эквивалентные массы которой рассчитывались методом
идентификации по данным расчёта свободных колебаний КЕ-модели ротора.
Изначально рассматривалась дискретная трехмассовая модель, которая затем в
силу приблизительной симметрии двух опорного ротора была заменена двух
массовой.
47
Знаменщиков, Ярослав Володимирович, Ярослав Владимирович Знаменщиков, Yaroslav Volodymyrovych Znamenshchykov, О. К. Кононов, Олександр Анатолійович Доброжан, Александр Анатольевич Доброжан, Oleksandr Anatoliiovych Dobrozhan, Анатолій Сергійович Опанасюк, Анатолий Сергеевич Опанасюк, and Anatolii Serhiiovych Opanasiuk. "Використання технології тривимірного друку для формування струмознімальних контактів в тонкоплівкових сонячних перетворювачах." Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65299.
Abstract:
В процесі виготовлення тонкоплівкових сонячних перетворювачів важливим етапом є утворення струмозмімальних контактів на поверхні плівки та їх з’єднання із зовнішніми електричними колами. В порівнянні з традиційними способами отримання контактів, такими як вакуумне термічне напилення, магнетронне розпилення, хімічні методи, технологія тривимірного друку спеціальними струмопровідними чорнилами являється перспективним дешевим методом, що дозволяє за короткий час створити струмознімальні контакти необхідної форми із заданими властивостями.
48
Zinchenko, I. S., Tetiana Oleksandrivna Protasova, Тетяна Олександрівна Протасова, and Татьяна Александровна Протасова. "The use of gsm-channel in security systems." Thesis, Sumy State University, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65499.
Abstract:
The opportunities provided by mobile operators are increasingly used in surveillance systems. To date wireless security systems on the basis of GSM is widespread due to their relatively low cost and ease of installation and operation. The use of GSM obviates the need to expand its network of repeaters – repeaters are used by GSM operators. As a result, it is possible to protect objects wherever confidently works GSM network operator.
49
Дудник, Б. В. "Конвективний теплообмін необмеженого циліндричного середовища з зовнішнім середовищем." Thesis, Сумський державний університет, 2017. http://essuir.sumdu.edu.ua/handle/123456789/65399.
Abstract:
Знайти температуру необмеженої круглої циліндричної труби 𝑅1 ≤
𝑟 ≤ 𝑅2, якщо її початкова температура дорівнює 𝑓(𝑟,𝜑) (0 ≤ 𝜑 ≤ 2𝜋),
а на зовнішній і внутрішній поверхнях відбувається конвективний
теплообмін з середовищем нульової температури.
50
Hain, Tobias Martin. "Structure formation and identification in geometrically driven soft matter systems." Thesis, Hain, Tobias Martin (2022) Structure formation and identification in geometrically driven soft matter systems. PhD thesis, Murdoch University, 2022. https://researchrepository.murdoch.edu.au/id/eprint/65699/.
Abstract:
Subdividing space through interfaces leads to many space partitions that are relevant to soft matter self-assembly. Prominent examples include cellular media, e.g. soap froths, which are bubbles of air separated by interfaces of soap and water, but also more complex partitions such as bicontinuous minimal surfaces.
Using computer simulations, this thesis analyses soft matter systems in terms of the relationship between the physical forces between the system’s constituents and the structure of the resulting interfaces or partitions. The focus is on two systems, copolymeric self-assembly and the so-called Quantizer problem, where the driving force of structure formation, the minimisation of the free-energy, is an interplay of surface area minimisation and stretching contributions, favouring cells of uniform thickness.
In the first part of the thesis we address copolymeric phase formation with sharp interfaces. We analyse a columnar copolymer system “forced” to assemble on a spherical surface, where the perfect solution, the hexagonal tiling, is topologically prohibited. For a system of three-armed copolymers, the resulting structure is described by solutions of the so-called Thomson problem, the search of minimal energy configurations of repelling charges on a sphere. We find three intertwined Thomson problem solutions on a single sphere, occurring at a probability depending on the radius of the substrate.
We then investigate the formation of amorphous and crystalline structures in the Quantizer system, a particulate model with an energy functional without surface tension that favours spherical cells of equal size. We find that quasi-static equilibrium cooling allows the Quantizer system to crystallise into a BCC ground state, whereas quenching and non-equilibrium cooling, i.e. cooling at slower rates then quenching, leads to an approximately hyperuniform, amorphous state. The assumed universality of the latter, i.e. independence of energy minimisation method or initial configuration, is strengthened by our results. We expand the Quantizer system by introducing interface tension, creating a model that we find to mimic polymeric micelle systems: An order-disorder phase transition is observed with a stable Frank-Caspar phase.
The second part considers bicontinuous partitions of space into two network-like domains, and introduces an open-source tool for the identification of structures in electron microscopy images. We expand a method of matching experimentally accessible projections with computed projections of potential structures, introduced by Deng and Mieczkowski (1998). The computed structures are modelled using nodal representations of constant-mean-curvature surfaces. A case study conducted on etioplast cell membranes in chloroplast precursors establishes the double Diamond surface structure to be dominant in these plant cells. We automate the matching process employing deep-learning methods, which manage to identify structures with excellent accuracy.