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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.
331

Using Instance-Level Meta-Information to Facilitate a More Principled Approach to Machine Learning

Smith, Michael Reed 01 April 2015 (has links) (PDF)
As the capability for capturing and storing data increases and becomes more ubiquitous, an increasing number of organizations are looking to use machine learning techniques as a means of understanding and leveraging their data. However, the success of applying machine learning techniques depends on which learning algorithm is selected, the hyperparameters that are provided to the selected learning algorithm, and the data that is supplied to the learning algorithm. Even among machine learning experts, selecting an appropriate learning algorithm, setting its associated hyperparameters, and preprocessing the data can be a challenging task and is generally left to the expertise of an experienced practitioner, intuition, trial and error, or another heuristic approach. This dissertation proposes a more principled approach to understand how the learning algorithm, hyperparameters, and data interact with each other to facilitate a data-driven approach for applying machine learning techniques. Specifically, this dissertation examines the properties of the training data and proposes techniques to integrate this information into the learning process and for preprocessing the training set.It also proposes techniques and tools to address selecting a learning algorithm and setting its hyperparameters.This dissertation is comprised of a collection of papers that address understanding the data used in machine learning and the relationship between the data, the performance of a learning algorithm, and the learning algorithms associated hyperparameter settings.Contributions of this dissertation include:* Instance hardness that examines how difficult an instance is to classify correctly.* hardness measures that characterize properties of why an instance may be misclassified.* Several techniques for integrating instance hardness into the learning process. These techniques demonstrate the importance of considering each instance individually rather than doing a global optimization which considers all instances equally.* Large-scale examinations of the investigated techniques including a large numbers of examined data sets and learning algorithms. This provides more robust results that are less likely to be affected by noise.* The Machine Learning Results Repository, a repository for storing the results from machine learning experiments at the instance level (the prediction for each instance is stored). This allows many data set-level measures to be calculated such as accuracy, precision, or recall. These results can be used to better understand the interaction between the data, learning algorithms, and associated hyperparameters. Further, the repository is designed to be a tool for the community where data can be downloaded and uploaded to follow the development of machine learning algorithms and applications.
332

ELUCIDATING THE CHARGE TRANSPORT OF A RADICAL SYSTEM FROM A COMBINED EXPERIMENTAL AND COMPUTATIONAL APPROACH

Ying Tan (15339337) 27 April 2023 (has links)
<p>Radical polymers bearing open-shell moieties at their pendant sites offer potential advantages in processing, stability, and optoelectronic properties compared to conventional doped conjugated polymers. The rapid development of radical-containing polymers has occurred across various applications in energy storage devices and electronic systems. However, significant gaps still exist in understanding the key structure-property-function relationships governing charge transport phenomena in these materials. Most reported radical conductors primarily rely on (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) radicals, which raises fundamental questions about the ultimate limits of charge transport capabilities and the impact of radical chemistry choice on material deficiencies. Moreover, an understanding gap persists when it comes to connecting the computable electronic features of individual units and the charge transport behavior of these materials in condensed phases. This dissertation seeks to address these gaps by developing a molecular understanding of charge transport in radical-bearing materials through a combined computational and experimental approach.</p> <p><br></p> <p>The initial stage of this dissertation investigated the impact of dimeric orientations and interactions on charge transport by conducting a density functional theory (DFT) study on a diverse set of open-shell chemistries relevant to radical conductors. The results revealed the anomalously high reorganization energies of the TEMPO radical due to strong spin-localization, which may result in inefficient charge transfer. Additionally, a significant mismatch was identified between dimeric conformations favored by intermolecular interactions and those maximizing charge transfer. This study provided new insights into the impact of steric hindrance and spin delocalization on elementary charge transfer steps and suggests opportunities for exploiting directing interactions to enhance charge transport in these materials.</p> <p><br></p> <p>Building upon these findings, we established a direct relationship between the molecular architecture and intrinsic charge transport properties. To accomplish this, single-molecule characterization methods (i.e., break junction techniques) were implemented to study the nanoscale charge transport properties of radical-containing oligomeric nonconjugated molecules. Temperature-dependent measurements and molecular modeling revealed that the presence of radicals improves tunneling at the nanoscale. Integrating open-shell moieties into nonconjugated molecular structures significantly enhances charge transport, thereby characterizing charge transport through radicals at the individual level and opening new avenues for implementing molecular engineering in the field of nanoelectronics.</p> <p><br></p> <p>To further connect the electronic properties of repeat units with the condensed-phase charge transport behavior of radical polymers, a quantum chemical study was carried out to explicitly evaluate the interplay between polymer design, open-shell chemistries, and intramolecular charge transport. After comprehensive conformational sampling of the configurational space of radical polymers, we determined their anticipated intrachain charge transport values by utilizing graph-based transport metrics. We show that charge transport in radical polymers primarily hinges on the choice of radical chemistry, which in turn affects the optimal selection of backbone chemistry and spacer group to ensure proper radical alignment and prevent undesired trap states. These findings highlight the potential for a substantial synthetic exploration in radical polymers for radical conductors.</p> <p><br></p> <p>In summary, this dissertation provides compelling evidence of radical-mediated charge transport and suggests potential design guidelines to enhance the charge transfer behavior of radical-containing polymer materials. Furthermore, these findings inform future research directions in fine-tuning molecular engineering and modular design to enable the development of radical-based materials and their end-use applications in organic electronics.</p>
333

Malmöelevers förutsättningar i grundskolan - En kvalitativ komparativ analys [QCA] omskolresursers betydelseutifrån malmöelevers socioekonomiskabakgrundsfaktorerförPISA-resultateni årskurs 9

Thornberg, Johanna January 2016 (has links)
I studien har 12 elevgrupper från 10 kommunala skolor i Malmö studerats statistiskt frånläsåren 2005/06 till 2013/14. Utifrån elevernas socioekonomiska bakgrund undersöktes effekten av skolornas resursutbud för PISA-resultaten i årskurs 9. Genom teorier om skolan som arena för social reproduktion av medelklassens värden, visade analysen att skolan inte uppväger för arbetarklasselever utan eftergymnasialt utbildade föräldrar. Slutsatserna visade att observationsgruppernas höga lärarbehörighet kombinerat med ökad lärartäthet för utsatta elevgrupper, inte ensamt utjämnar bakgrundsrelaterad skolsegregation. Som insatskomplement bör skolornas elevsammansättning ses som en administrativt förändringsbar resurs, jämte utökat arbete för bredare konsensus mellan hem och skola kring utbildningens betydelse och form. / This study carries out a Qualitative Comparative Analysis [QCA] of 12 groups of studentsfrom 10 public schools in Malmoe. Based on students’ socioeconomic background, the study examines the effect of school resources across 9 years of elementary school; on PISA results in grade 9. Using the theoretical framework that school is an institution to promote social reproduction of middle-class values; the analysis demonstrates that school does not compensate working class students. The study's conclusions where that the observation groups generally high teaching qualifications; combined with increased teacher ratio for vulnerable student groups, not alone were sufficient resources to equalize background related school segregation. These need to be complemented with a broader consensus between home and school about the importance of education and its execution. Also the school pupil homogeneous composition should thereto be seen as an administrative opportunity to level the playing field in the present segregated school situation.
334

Планирование и прогнозирование финансовых результатов деятельности кредитных организаций : магистерская диссертация / Planning and forecasting financial results activity of credit organizations

Пупкова, И. А., Pupkova, I. A. January 2019 (has links)
Final qualifying work (master's thesis) is devoted to the study of planning and forecasting system financial results of credit organizations. The subject of the study is the methodological and methodical problems of planning and forecasting efficiency, rationalization of the structure of the strategic plan. The main purpose of the master's thesis is to develop and scientific substantiation of theoretical and methodological provisions about planning and forecasting financial results activity of banks, identify problems in the existing system and propose ways to solve them. In conclusion, the recommendations for improving the financial planning and forecasting system. / Выпускная квалификационная работа (магистерская диссертация) посвящена исследованию системы планирования и прогнозирования финансовых результатов кредитных организаций. Предметом исследования выступают методологические и методические проблемы эффективности планирования и прогнозирования, рационализации структуры стратегического плана. Основной целью магистерской диссертации является разработка и научное обоснование теоретических и методических положений о планировании и прогнозировании финансовых результатов деятельности банка, выявлении проблем в существующей системе и предложении путей их решения. В заключении обозначены рекомендации по совершенствованию системы финансового планирования и прогнозирования.
335

Characterization of Lamps of IRF Solar Simulator

Sonna, Mrunmayee January 2023 (has links)
The Swedish Institute of Space Physics (IRF) at Kiruna focuses on research activities in the ionosphere, magnetosphere, and upper atmosphere of the planet as well as the development and production of various sensors and detectors for space research. The test facility includes the IRF SpaceLab which is equipped with multiple testing equipment. One of the testing resources available is the Solar Simulator, which consists of a vacuum chamber equipped with four metal halide lamps that produce a spectrum closely resembling that of the Sun. When any spacecraft payload or instrument is exposed to the Sun and its radiations, the most important factors to consider are the type of radiation, flux, and how the exposed material will react. Thermal designing and solar balance tests are important factors in achieving expected conditions for different missions. By testing and verifying these lamps, this solar simulator can be used not only for IRF missions but also for other institutes and private organizations that can access it. The characterization of four lamps is done in terms of temperature distribution, radiation, and power. According to preliminary experimental measured values obtained from the setup, exposed material, and its properties can be varied and the best suitable coating can be selected that includes α (absorptivity) and ϵ (emissivity) valueconsideration. The thesis is divided into four phases: Designing, Manufacturing, Testing, and Analyzing. Before entering into these phases, the basic knowledge of thermal engineering and thermal simulation is acquired. Thermal modeling and simulations are done in Airbus Defence &amp; Space’s Systema Thermica software tool. The design phase includes designing a frame structure and a 350 x 350 mm screen in Autodesk Inventor software. Manufacturing of the frame structure and the screen was done in the IRF workshop. This screen kept hanging with the support of a frame structure which is mounted on the copper table inside the chamber. The screen is kept in the field of view of each lamp and every lamp is illuminated accordingly. The analysis is done by measuring the temperature of the back side of the screen. Temperature sensors were mounted and clamped mechanically instead of kapton tape to avoid direct contact with the screen. The obtained values are analyzed and compared with the thermally simulated values. Pressure and the temperature of the system were monitored with independent systems throughout the test procedure. This thesis report could operate as a foundation for future examination of the solar simulator’s lamps in order to determine precise efficiency.
336

REKRYTERING AV KOMMUNDIREKTÖRER : En empirisk studie av offentliga värden i platsannonser

Jonsson, Lisa, Oscarsson, Emelie January 2023 (has links)
The essay aims to empirically examine which public administration values that are used when recruiting municipal directors, with a focus on whether job advertisements contain a comprehensive picture of this important public mission, which can contribute to suitable people applying for this type of position. The purpose is limited to the following questions, which we intend to construct a theoretical framework around in order to be able to answer at a later stage: • Which public values are prominent in job advertisements for the recruitment of municipal directors and which values appear to a limited extent or not at all? • How are public values formulated in job advertisements for municipal directors in the form of word choice and reasoning? • What does the process look like in the creation of job advertisements for municipal directors? Recruiting well in terms of presenting from the beginning a comprehensive picture of the values and tasks of the position is important; especially in public administrations as employment affects the social-, political-, and economic parts of society. The issue of recruitment becomes interesting, as we can study to what extent democratic and economic values that managers need to relate to emerge already in the initial phase of recruitment. The municipal director becomes particularly relevant because he/she works in an organization that manages several welfare services within a broad spectrum with a large turnover. Through an empirical analysis of a quantitative and qualitative nature of job advertisements and e-mail interviews, we can conclude that it is economic values that primarily appear in the job advertisements. The descriptive study has managed to produce data which indicates that there is a local variation of values, that the complexity of the role does not emerge, it focuses to a large extent on economic values. This data may be useful for future studies that may conceivably investigate potential institutional change in public management or if party affiliation affects the content of the advertisement.
337

CONTEXT-BASED PUBLICATION SEARCH PARADIGM IN LITERATURE DIGITAL LIBRARIES

Ratprasartporn, Nattakarn January 2008 (has links)
No description available.
338

Parents’ Perspectives: Child’s Whole Exome Sequencing (WES) Research Results of Uncertain Significance

Tran, Grace 17 October 2014 (has links)
No description available.
339

Retrospective Comparison of In-person versus Telephone Results Disclosure Counseling for BRCA1/2 Genetic Testing

Doughty, Courtney R. 22 August 2008 (has links)
No description available.
340

The Effects of Incomplete Knowledge of Results on Response Bias in an Auditory Detection Task

Davis, Matthew J. January 2015 (has links)
No description available.

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