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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Kooperativní teorie her v lokálních konfliktech / Cooperative game theory in local conflicts

Ilavská, Adriana January 2019 (has links)
The Cooperative Game Theory is a scientific discipline which offers rich mathematical apparatus for describing complex situations in the social reality. Its apparatus includes an extension to hierarchical structures and therefore can be applied to numerous research problems from the International Relations field. However, a cooperative game theoretical approach is very scarcely used. The main goal of the diploma thesis is to demonstrate, on the research problem of decision making in participation in local conflicts, the benefits of results that can be achieved by the application of the Cooperative Game Theory. In the first part of the thesis, theoretical foundations are laid and basic concepts are introduced. The second part is focused on forming a series of models of cooperative games with hierarchical structures from four local conflict situations, which are subsequently restricted in order to describe authoritative relations in structure. Restricted games are solved, the results are interpreted and evaluation of how these results can contribute to addressing the research problem follows.
12

Porous Metal Oxide Materials Through Novel Fabrication Procedures

Hendricks, Nicholas 01 September 2012 (has links)
Porous metal oxide materials, particularly those comprised of silica or titania, find use in many applications such as low-k dielectric materials for microelectronics as well as chemical sensors, micro/nanofluidic devices, and catalyst substrates. For this dissertation, the focus will be on the processing of porous metal oxide materials covering two subjects: hierarchical porosity exhibited over two discrete length scales and incorporation of functional nanomaterials. To generate the porous silica materials, the technique of supercritical carbon dioxide infusion (scCO2) processing was heavily relied upon. Briefly, the scCO2 infusion processing utilizes phase selective chemistries within a pre-organized amphiphilic block copolymer template using scCO2 as the reaction medium to selectively hydrolyze and condense silica precursors to yield mesoporous materials. To further develop the scCO2 infusion processing technique, hierarchically porous silica materials were generated on unique substrates. Hierarchically structured silica nanochannels were created using a combination of scCO2 infusion processing and nanoimprint lithography (NIL) patterned sacrificial polymer templates to yield mesopores and airgap structures respectively. Hierarchically porous silica materials were also generated on alternative substrates, in the form of cellulose filter paper, which were used to host the amphiphilic block copolymer template to yield tri-modal porosity silica materials. To extend the applicability of mesoporous silica generated from scCO2 infusion processing, functional nanomaterials, in the form of pre-synthesized gold nanoparticles, fullerene derivatives, and polyhedral oligomeric silsequioxanes (POSS) were embedded within the mesoporous silica to produce unique composite materials. The functional nanomaterials were able to impart specific properties, typically only affored to the functional nanomaterials, upon the mesoporous silica thin film with an example being enhanced thermal and hydrothermal properties of mesoporous silica doped with POSS molecules. To continue research with functional nanomaterials, nanoparticle composite materials, comprised of crystalline metal oxide nanoparticles and binder/filler materials, either organic or inorganic, were also evaluated as novel NIL resist materials. Patterning of the nanoparticle composite materials, specifically, but not limited to, titanium dioxide based materials, into two dimensional, arbitrarily shaped, sub-micron features was readily achieved on either rigid or flexible substrates. True three-dimensional structures, based on nanoparticle composite materials, were fabricated by utilizing release layers and pre-patterned substrates.
13

MULTIFUNCTIONAL COATINGS TO PREVENT SPREAD OF INFECTIOUS DISEASES

Abu Jarad, Noor January 2024 (has links)
Healthcare-associated infections present an escalating worldwide issue, further intensified by the emergence of antimicrobial resistance and the spread of pathogens on surfaces. Current infection prevention methods have shown limited effectiveness, leading to several health issues, an overuse of antibiotics, and a continuous threat of surface recontamination. In response, extensive research has focused on bioinspired omniphobic smart coatings that effectively reduce the contact area available for pathogen attachment, achieved through an increase in surface roughness and apparent surface energy. This thesis introduces a new class of an omniphobic spray-coating, featuring hierarchical structured polydimethylsiloxane (PDMS) microparticles coated with gold nanoparticles, encompassing primary microscale (~0.23 𝜇m) and secondary nanoscale (~5 nm) buckyball and labyrinth wrinkles. This substrate-independent coating efficiently repels a wide range of liquids, including pathogens, even under harsh conditions like high temperatures, ultraviolet (UV) exposure, and abrasions. Repellency tests comparing coated and uncoated gloves revealed that uncoated gloves spread contamination to 50 secondary surfaces, while coated gloves transferred fewer bacteria and viruses to just three and two surfaces, respectively. The investigation extended to the coating's biocidal capabilities, incorporating gold nanoparticles functionalized with mercapto-silane to create a "Repel and Kill" coating. This process initiates chemisorption through thiol-gold bonding, allowing for the formation of diverse surface structures, including three-dimensional self-assembly, multilayers, and island structures. These modifications significantly enhance the roughness and hydrophobicity of the gold nanoparticles, amplifying their biocidal effectiveness. The wrinkled structure of PDMS contribute to repellency, while the functionalized gold nanoparticles play a crucial role in the antimicrobial property. This enhancement was evident in the antibacterial tests, which exhibited an immediate 99.90% reduction in bacterial adhesion for both MRSA and Pseudomonas aeruginosa (P. aeruginosa), followed by an additional 99.70% and 99.90% reduction in bacterial growth after 8 hours for MRSA and P. aeruginosa, respectively. Moreover, the coating's antiviral properties were confirmed, demonstrating a 98% reduction in the transfer of the bacterial virus Phi6. Recognizing the role of hospital fabrics as potential reservoirs for infection transmission, primarily due to their ability to sustain bacterial growth for extended periods, especially in the presence of bodily fluids, we took further steps to modify the wrinkled PDMS microparticles. This involved the incorporation of silver nanoparticles, capped with a positively charged ligand known as branched polyethyleneimine (bPEI). Additionally, we integrated a colorimetric sensor, giving rise to the "Repel, Kill, and Detect" smart coating. The transition of color from blue to green-yellow provided a tangible indicator of contamination detection based on the acidic mileu of the biofilms. To evaluate its realworld effectiveness, we conducted simulations of infection transmission in hospital environments, resulting in a remarkable reduction in pathogen adhesion from urine and feces by 99.88% and 99.79%, respectively, compared to uncoated fabrics. To further enhance the validation of our results, we employed a powerful deep learning network architecture, that determined whether the surfaces are contaminated or safe. In the face of evolving health challenges, this coating emerges as a resilient and adaptable solution, promising to enhance overall safety and alleviate the burden of infectious diseases. / Thesis / Doctor of Engineering (DEng) / The prolonged survival of pathogens on surfaces, significantly highlighted by the COVID-19 global pandemic, has intensified the urgency of addressing contamination on high-touch surfaces. Engineered surface coatings with repellent properties have emerged as a long-lasting and health-conscious solution for infection prevention and control. In this thesis, we introduce a new class of multifunctional engineered coatings featuring hierarchical structures adorned with biocidal nanoparticles and an integrated colorimetric sensor. We comprehensively investigate these coatings' multifunctional capabilities to repel, exterminate, and detect contaminants. Through specific characterization tests involving a wide range of pathogens, including viruses, bacteria, and fungi, within complex biological fluids like urine and feces, this research culminates in the development of surface coatings equipped with both antimicrobial and pathogen-sensing capabilities. In addition to advancing our understanding of surface hierarchy and chemical modifications for repellency and biocidal activity, this thesis yields insights into the dynamics of biofouling and pathogen transfer, with the overarching goal of reducing pathogen transmission via surfaces.
14

Scalable Visual Hierarchy Exploration

Stroe, Ionel Daniel 10 May 2000 (has links)
More and more modern computer applications, from business decision support to scientific data analysis, utilize visualization techniques to support exploratory activities. Various tools have been proposed in the past decade to help users better interpret data using such display techniques. However, most do not scale well with regard to the size of the dataset upon which they operate. In particular, the level of cluttering on the screen is typically unacceptable and the performance is poor. To solve the problem of cluttering at the interface level, visualization tools have recently been extended to support hierarchical views of the data, with support for focusing and drilling-down using interactive brushes. To solve the scalability problem, we now investigate how best to couple such a visualization tool with a database management system without losing the real-time characteristics. This integration must be done carefully, since visual user interactions implemented as main memory operations do not map directly into efficient database operations. The main efficiency issue when doing this integration is to avoid the recursive processing required for hierarchical data retrieval. For this problem, we have develop a tree labeling method, called MinMax tree, that allows the movement of the on-line recursive processing into an off-line precomputation step. Thus, at run time, the recursive processing operations translate into linear cost range queries. Secondly, we employ a main memory access strategy to support incremental loading of data into the main memory. The techniques have been incorporated into XmdvTool, a multidimensional visual exploration tool, in order to achieve scalability. The tool now successfully scales up to datasets of the order 10^5-10^7 records. Lastly, we report experimental results that illustrate the impact of the proposed techniques on the system's overall performance.
15

[en] PSYCHOMETRIC PROPRIETIES OF THE ANXIETY SENSITIVITY INDEX REVISED / [pt] PROPRIEDADES PSICOMÉTRICAS DA ESCALA DE SENSIBILIDADE À ANSIEDADE REVISADA

MARIA RACHEL PESSANHA GIMENES ESCOCARD 26 December 2007 (has links)
[pt] Sensibilidade à Ansiedade (ex: medo dos sintomas relacionados à ansiedade assim como a crença de que esses sintomas possam ter conseqüências desastrosas) é um importante constructo psicológico envolvido na etiologia de diferentes Transtornos de Ansiedade. O presente estudo avaliou as propriedades psicométricas e a estrutura fatorial da Escala de Sensibilidade à Ansiedade Revisada (ESA-R) em 585 pacientes brasileiros com diagnóstico primário de Transtorno de Ansiedade. Os resultados indicaram que a presente versão da ESAR possui boa consistência interna e boa correlação de coeficiente item-total. A análise fatorial exploratória sugeriu uma estrutura hierárquica composta por um fator único de primeira ordem e quatro fatores de segunda ordem relacionados a: 1) medo dos sintomas respiratórios e cardiovasculares, 2) medo de descontrole cognitivo, 3) medo que as reações de ansiedade sejam observadas publicamente, e 4) medo dos sintomas gastrintestinais. Os fatores de primeira e segunda ordem da ESA-R comparados com os diferentes grupos de Transtorno de Ansiedade indicaram que pacientes com Transtorno do Pânico apresentaram um escore significativamente mais elevados nas dimensões da ESA - R, com exceção para o fator de segunda ordem medo do descontrole cognitivo. / [en] Anxiety sensitivity (i.e., fear of anxiety-related symptoms due to the belief that these symptoms will produce harmful consequences) is an important psychological construct involved in the etiology of different anxiety disorders. The present study evaluated the psychometric proprieties and the factor structure of the Anxiety Sensitivity Index-Revised (ASI-R) among 585 Brazilian patients with primary anxiety disorder diagnosis. Results indicated that the present version of the ASI-R had good internal consistency and item-total correlation coefficients. Exploratory factor analyses suggested a hierarchical structure composed by a single higher-order factor and four lower-order factors related to 1) fear of respiratory and cardiovascular symptoms, 2) fear of cognitive dyscontrol, 3) fear of publicly observable anxiety reactions, and 4) fear of gastrointestinal symptoms. ASI-R higher- and lower-order factor scores comparisons across the different anxiety disorder groups indicated that panic disorder patients scored significantly higher in the ASI-R dimensions, except for the fear of cognitive dyscontrol lowerorder factor.
16

Multimetallic Hierarchical Aerogels: Shape-engineering of the Building Blocks for efficient electrocatalysis

Cai, Bin, Dianat, Arezoo, Hübner, Rene, Liu, Wei, Wen, Dan, Benad, Albrecht, Sonntag, Luisa, Gemming, Thomas, Cuniberti, Gianaurelio, Eychmüller, Alexander 19 July 2018 (has links) (PDF)
A new class of multimetallic hierarchical aerogels composed entirely of interconnected Ni‐PdxPty nano‐building‐blocks with in situ engineered morphologies and compositions is demonstrated. The underlying mechanism of the galvanic shape‐engineering is elucidated in terms of nanowelding of intermediate nanoparticles. The hierarchical aerogels integrate two levels of porous structures, leading to improved electrocatalysis performance.
17

Addressing an old issue from a new methodological perspective : a proposition on how to deal with bias due to multilevel measurement error in the estimation of the effects of school composition

Televantou, Ioulia January 2014 (has links)
With educational effectiveness studies, school-level aggregates of students' characteristics (e.g. achievement) are often used to assess the impact of school composition on students' outcomes – school compositional effects. Empirical findings on the magnitude and direction of school compositional effects have not been consistent. Relevant methodological studies raise the issue of under-specification at level 1 in compositional models - evident when the student-level indicator on which the aggregation is based is mis-measured. This phenomenon has been shown to bias compositional effect estimates, leading to misleading effects of the aggregated variables – phantom compositional effects. My thesis, consisted of three separate studies, presents an advanced methodological framework that can be used to investigate the effect of school composition net of measurement error bias. In Study 1, I quantify the impact of failing to account for measurement error on school compositional effects as used in value added models of educational effectiveness to explain relative school effects. Building on previous studies, multilevel structural equation models are incorporated to control for measurement error and/or sampling error. Study 1a, a large sample of English primary students in years one and four (9,059 students from 593 schools) reveals a small, significant and negative compositional effect on students' subsequent mathematics achievement that becomes more negative after controlling for measurement error. Study 1b, a large study of Cyprus primary students in year four (1694 students in 59 schools) shows a small, positive but statistically significant effect that becomes non-significant after controlling for measurement error. Further analyses with the English data (Study 2), demonstrates a negative compositional effect of school average mathematics achievement on subsequent mathematics self-concept – a Big Fish Little Pond Effect (BFLPE). Adjustments for measurement and sampling error result in more negative BFLPEs. The originality of Study 2 lies in verifying BFLPEs for students as young as five to eight/nine years old. Bridging the findings related to students' mathematics self-concept (Study 2) and the findings on students’ mathematics achievements (Study 1a), I demonstrate that the prevalence of BFLPEs with the English data partly explains the negative compositional effect of school average mathematics achievement on students' subsequent mathematics achievement. Lastly, in Study 3 I consider an alternative approach to school accountability to conventional value added models, namely the Regression Discontinuity approach. Specifically, I use the English TIMSS 1995 primary (years four and five) and secondary (years eight and nine) data to investigate the effect of one extra year of schooling on students' mathematics achievement and the variability across schools in their absolute effects. The extent to which school composition, as given by school average achievement, correlates with schools' added-year effects is addressed. Importantly the robustness of the RD estimates to measurement error bias is demonstrated. My findings have important methodological, substantive and theoretical implications for on-going debates on the school compositional effects on students' outcomes, because nearly all previous research has been based on traditional approaches to multilevel models, which are positively biased due to the failure to control for measurement error.
18

Patriarchy and Masculinity in Doris Lessing's The Fifth Child and in Ben in the World

Sundberg, Björn January 2011 (has links)
The English novelist, Doris Lessing elucidates the rigidity of a society, which is based upon patriarchy, in her novels, The Fifth Child and Ben in the World. This essay illustrates the causes and the effects of a patriarchal system in the light of feminist ideology supported by Freud’s theories about the acquisition of gender roles. The analysis in this essay of patriarchy and masculinity shows that the novels’ societies as a whole, as well as their criminal subcultures are upheld by people who hold prejudice against others, who do not fit in society’s normal structures, believe in authoritarian social systems and prefer rational solutions to decisions for reasons of conscience. Lessing depicts the complexity of the social relations between characters of different social classes and their relations to society’s institutions. Her unprejudiced penetration into the minds of society’s marginalized people and into the minds of those who represent the oppressive established society illuminates different sides of patriarchy. Lessing gives us to understand that it is extremely difficult, from a moral point of view, to distinguish the established society from its criminal subcultures or society’s oppressors from its victims. Society’s accepted gender roles in the patriarchal system are often ironically described in these novels, certainly with the aim of making us question normative manners, habits and attitudes.
19

Multimetallic Hierarchical Aerogels: Shape-engineering of the Building Blocks for efficient electrocatalysis

Cai, Bin, Dianat, Arezoo, Hübner, Rene, Liu, Wei, Wen, Dan, Benad, Albrecht, Sonntag, Luisa, Gemming, Thomas, Cuniberti, Gianaurelio, Eychmüller, Alexander 19 July 2018 (has links)
A new class of multimetallic hierarchical aerogels composed entirely of interconnected Ni‐PdxPty nano‐building‐blocks with in situ engineered morphologies and compositions is demonstrated. The underlying mechanism of the galvanic shape‐engineering is elucidated in terms of nanowelding of intermediate nanoparticles. The hierarchical aerogels integrate two levels of porous structures, leading to improved electrocatalysis performance.
20

Hierarchical Porous Structures with Aligned Carbon Nanotubes as Efficient Adsorbents and Metal-Catalyst Supports

Vijwani, Hema 04 June 2015 (has links)
No description available.

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