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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.
561

Beyond Recidivism: Learning with Formerly Incarcerated Men About Youth Incarceration

Bastian, Scott Patrick 18 March 2016 (has links) (PDF)
Too often, the truth behind a phenomenon is not sought through the perspectives of the people who lived that phenomenon—“the masters of inquiry” into their own realities, as Paulo Freire (1982, p. 29) has explained. Voice is the most powerful, reliable medium for collecting data based on lived experiences, if we are to gain genuine insight into the phenomenon (Freire, 1982). Focusing on the lived experiences of four formerly incarcerated young men of color, this study gave each participant the space to not only recall specific events and times, but to critically reflect on their lives—becoming more critically aware of their individual journeys and constructing new knowledge of the injustices that relate to the school-to-prison pipeline, including recommendations for change. This study sought to answer the following research questions through the voices of the participants: (a) Based on their collective and individual journeys through the juvenile justice system, how do formerly incarcerated youth describe their experiences? (b) What recommendations do formerly incarcerated young men have for reducing youth incarceration and recidivism rates? The participants provided rich narratives that answered each research question with the expert knowledge that can only be derived from firsthand experience. Through careful analysis of the data, several major themes emerged, tying together the experiences of each participant with the findings from the literature. Each participant spoke passionately on not only the need for change, but also specific recommendations for change. It is the power of their poignant insights that ground conclusions offered in this study.
562

A STUDY ON THE IMPACT OF PREPROCESSING STEPS ON MACHINE LEARNING MODEL FAIRNESS

Sathvika Kotha (18370548) 17 April 2024 (has links)
<p dir="ltr">The success of machine learning techniques in widespread applications has taught us that with respect to accuracy, the more data, the better the model. However, for fairness, data quality is perhaps more important than quantity. Existing studies have considered the impact of data preprocessing on the accuracy of ML model tasks. However, the impact of preprocessing on the fairness of the downstream model has neither been studied nor well understood. Throughout this thesis, we conduct a systematic study of how data quality issues and data preprocessing steps impact model fairness. Our study evaluates several preprocessing techniques for several machine learning models trained over datasets with different characteristics and evaluated using several fairness metrics. It examines different data preparation techniques, such as changing categories into numbers, filling in missing information, and smoothing out unusual data points. The study measures fairness using standards that check if the model treats all groups equally, predicts outcomes fairly, and gives similar chances to everyone. By testing these methods on various types of data, the thesis identifies which combinations of techniques can make the models both accurate and fair.The empirical analysis demonstrated that preprocessing steps like one-hot encoding, imputation of missing values, and outlier treatment significantly influence fairness metrics. Specifically, models preprocessed with median imputation and robust scaling exhibited the most balanced performance across fairness and accuracy metrics, suggesting a potential best practice guideline for equitable ML model preparation. Thus, this work sheds light on the importance of data preparation in ML and emphasizes the need for careful handling of data to support fair and ethical use of ML in society.</p>
563

[pt] AVALIAÇÃO DE REPAROS COMPÓSITOS NA RESTAURAÇÃO DA INTEGRIDADE ESTRUTURAL DE DUTOS COM CORROSÃO EXTERNA / [en] EVALUATION OF COMPOSITE REPAIRS IN THE RESTORATION OF STRUCTURAL INTEGRITY OF PIPELINES WITH EXTERNAL CORROSION

JONATHAN STREFLING AGUIAR 29 November 2021 (has links)
[pt] O presente trabalho apresenta evidências e visa confirmar as tendências gerais de que reparos feitos de materiais compósitos podem ser utilizados para restaurar completamente a integridade estrutural, desconsiderando efeitos de tempo, de segmentos de dutos que apresentam anomalias (defeitos) de perda de metal em sua superfície externa, causados por corrosão ou erosão. Sete espécimes tubulares de API 5L Gr. B e dez espécimes tubulares de API 5L X65 foram testados até a ruptura por meio de testes hidrostáticos monotônicos, com diâmetro externo nominal de 323,9 mm e espessura nominal de 8,38 mm. Duas amostras testadas não tinham defeitos. Seis espécimes apresentavam defeitos e não foram reparados. Nove espécimes apresentavam defeitos e foram reparados usando três sistemas de reparo de compósito diferentes. Os defeitos continham profundidades variando entre 40 por cento, 55 por cento e 70 por cento da espessura do tubo. Os reparos foram baseados em compósitos de epóxi e fibra de carbono, epóxi e fibra de vidro, e poliuretano e fibra de vidro. (FREIRE, VIEIRA, et al., 2019) Para a constatação dos resultados experimentais foram implementadas metodologias analíticas e numéricas. O método analítico utiliza equações normativas semiempíricas (ISO 24817) e da teoria de reparos para dutos (Equação de Equilíbrio). A avaliação numérica consiste no método de elementos finitos para modelagem do problema através do software ANSYS (marca registrada). Os sistemas de reparo dos três fornecedores mostraram ser eficazes e que reparos de compósitos podem restaurar completamente a integridade estrutural de dutos com defeito externo, desconsiderando efeitos de tempo, conforme o Fator de Resistência Remanescente (RSF) calculado. Os resultados dos testes mostraram que métodos analíticos e numéricos podem ser usados para compreensão do comportamento mecânico do problema. / [en] The present work presents evidence and aims to confirm general trends that repairs made of composite materials can be used to completely restore the structural integrity, disregarding the effects of aging, of pipeline segments that show anomalies (defects) in metal loss on their external surface, as a result by corrosion or erosion. Seven tubular specimens of API 5L Gr. B and ten tubular specimens of API 5L X65 were tested to rupture using monotonic hydrostatic tests, with a nominal external diameter of 323.9 mm and a nominal thickness of 8.38 mm. Two samples tested had no defects. Six specimens were defective and were not repaired. Nine specimens were defective and were repaired using three different composite repair systems. The defects contained depths ranging from 40 percent, 55 percent and 70 percent of the tube thickness. The repair systems were based on composites of epoxy and carbon fiber, epoxy and fiberglass, and polyurethane and fiberglass. (FREIRE, VIEIRA, et al., 2019) To verify the experimental results, analytical and numerical methodologies were implemented. The analytical method uses semi-empirical normative equations (ISO 24817 and ASME PCC-2) and repair theory for pipelines (Equilibrium Equation). Numerical evaluation consists of the finite element method for modeling the problem using ANSYS (trademark) software. The repair systems of the three suppliers proved to be effective according to the Remaining Resistance Factor (RSF) calculated, disregarding the effect of aging. The test results showed that analytical and numerical methods can be used to understand the mechanical behavior of the problem and that composite repairs can completely restore the structural integrity of pipelines with a loss in external wall thickness, avoiding production downtime and reducing the risk of accidents.
564

Environmental Philosophy after Standing Rock

Gessas, William Jeffrey 08 1900 (has links)
In 2016, An estimated 15,000 people representing 400 Indigenous Nations and non-indigenous allies gathered at the Standing Rock Sioux Reservation in solidarity against the Dakota Access Pipeline to protect Mni Sose, the Missouri River. They became known as the Water Protectors. This dissertation analyzes the response in environmental philosophy journals to the #noDAPL protest at Standing Rock. Even though the Stand at Standing Rock became one of the most important and monumental environmental protests of the last decade, neither Standing Rock nor the Water Protectors appear in environmental philosophy journals at all--not once. Why? I suggest a possible answer by exploring the Stand of the Water Protectors as a moment in a much longer continuous history of resistance to settler colonialism. Settler colonialism attempts to facilitate the erasure of Indigenous populations by colonial ones, in order to gain access to territory—to land. The omission of Standing Rock from environmental philosophy journals represents the ease with which environmental philosophy can become complicit in the project of settler colonial erasure and replacement through absence. Drawing on Indigenous land-based philosophies of kinship, Latin American decolonial philosophy, settler colonial theory, and frameworks of Indigenous environmental justice, I show how the geo-politics of colonialism have come to produce environmental injustice and planetary ruin. I work to break the silence on Standing Rock in environmental philosophy and allow the Water Protectors example to guide the project toward an environmental philosophy which centers colonialism and Indigenous resurgence as core concerns.
565

A Dredging Knowledge-Base Expert System for Pipeline Dredges with Comparison to Field Data

Wilson, Derek Alan 2010 December 1900 (has links)
A Pipeline Analytical Program and Dredging Knowledge{Base Expert{System (DKBES) determines a pipeline dredge's production and resulting cost and schedule. Pipeline dredge engineering presents a complex and dynamic process necessary to maintain navigable waterways. Dredge engineers use pipeline engineering and slurry transport principles to determine the production rate of a pipeline dredge system. Engineers then use cost engineering factors to determine the expense of the dredge project. Previous work in engineering incorporated an object{oriented expert{system to determine cost and scheduling of mid{rise building construction where data objects represent the fundamental elements of the construction process within the program execution. A previously developed dredge cost estimating spreadsheet program which uses hydraulic engineering and slurry transport principles determines the performance metrics of a dredge pump and pipeline system. This study focuses on combining hydraulic analysis with the functionality of an expert{system to determine the performance metrics of a dredge pump and pipeline system and its resulting schedule. Field data from the U.S. Army Corps of Engineers pipeline dredge, Goetz, and several contract daily dredge reports show how accurately the DKBES can predict pipeline dredge production. Real{time dredge instrumentation data from the Goetz compares the accuracy of the Pipeline Analytical Program to actual dredge operation. Comparison of the Pipeline Analytical Program to pipeline daily dredge reports shows how accurately the Pipeline Analytical Program can predict a dredge project's schedule over several months. Both of these comparisons determine the accuracy and validity of the Pipeline Analytical Program and DKBES as they calculate the performance metrics of the pipeline dredge project. The results of the study determined that the Pipeline Analytical Program compared closely to the Goetz eld data where only pump and pipeline hydraulics a ected the dredge production. Results from the dredge projects determined the Pipeline Analytical Program underestimated actual long{term dredge production. Study results identi ed key similarities and di erences between the DKBES and spreadsheet program in terms of cost and scheduling. The study then draws conclusions based on these ndings and o ers recommendations for further use.
566

Real time evaluation of weld quality in narrow groove pipe welding

Marmelo, Patricia C. January 2012 (has links)
With the growth in pipeline installations all over the world, there is a great demand for highly productive and robust welding systems. Mechanised pipe welding has been developed over the last 50 years and the present focus is towards development of automated pipeline welding systems. Pipeline welding automation is aimed at reducing costs and improving the installation quality. To attain fully automated pipe welding systems there is a need to rely on sensors and controls systems to mimic human like capabilities, such as visual inspection, in real time. The key aim of this work is to develop and evaluate methods of automatic assessment of weld bead shape and quality during narrow gap GMAW of transmission pipelines. This implies that the measured bead profile will be assessed to determine whether the bead shape will cause defects when the subsequent pass is deposited. Different approaches have been used to conquer the challenge that is emulating human reasoning, all with different objectives in mind. In spite of extensive literature research performed, very little information was found concerning the real time determination and assessment of bead shape quality and none of it was reported to be applied successfully to the pipeline industry. Despite the continuous development of laboratory laser vision systems commercial ones have been on the market for decades, some specifically developed for the welding application. Laser vision sensor systems provide surface profile information, and are the only sensors which can satisfactorily measure bead profile on a narrow groove. In order to be able to use them to automatically assess weld bead shape and quality, a deep understanding of their characteristics and limitations needs to be achieved. Once that knowledge was attained it was then applied to determine the best sensor configuration for this purpose. After that the development of human like judgment algorithms were developed to accomplish the aim that was set. Empirical rules were obtained from an experienced welder regarding the acceptability of bead shapes and were then applied in the developed system with good results. To scientifically evaluate and determine the rules to use in this system, further experiments would be required. The output of the system developed showed very accurate, reliable and consistent results that were true to the external measurements and comparisons performed. The developed system has numerous applications in the pipeline industry and it could easily be implemented on commercial systems.
567

Engineered landscapes: re-thinking sacrificed landscapes in the Canadian Prairies

Abdulrehman, Saira 21 January 2016 (has links)
The outcome of this practicum is the design of an "engineered landscape" that can anticipate, reveal and compensate for disturbances brought on by the Energy East Pipeline on local ecologies and communities.This practicum makes an argument for the increased consideration of qualitative values in contemporary landscape mitigation practice. The increased focus on qualitative values in landscape mitigation combined with the provision of facilities and landscapes necessary to build knowledge, skills and resources will result in landscapes and spaces that facilitate the empowerment of communities as stewards of the environment in the face of globalized industrialization and decreased federal/provincial funding. / February 2016
568

NATO-Russian relation status and prospectives

AKTI, Serkan 12 1900 (has links)
Approved for public release; distribution in unlimited. / Since the end of the Cold War, NATO has attributed great importance to the development of cooperation with Russia. This thesis, first, evaluates the main developments in NATO - Russian relations since 1991. Although Moscow and the Alliance established a NATO - Russia Council (NRC) and asserted the initiation of a qualitatively new relationship, Russia still needs to fulfill some requirements for catching up the Western standards. Russia's external relations and political, economic and security factors internal to Russia will determine the future of the relationship. This thesis examines Russia's political development and transformation of its economic system, and establishes the problems in its political and economic systems. It also examines Russia's problematic external relations in the region, and their impact on the NATO - Russian relationship. It looks into Russia's National Security Concept, explores regional conflicts such as Chechnya and Georgia, and the U.S. - NATO presence in Central Asia. Then, it examines the oil and natural gas transportation problems created by the Russian monopoly, and evaluates Russian technology transfers to Iran, particularly in the nuclear sector. Consequently, it evaluates the internal and external interactions mentioned above and offers conclusions about the prospects for security and stability in Europe. / Lieutenant, Turkish Navy
569

Risk to buried gas pipelines in landslide areas

Ferreira, Nelson John 09 September 2016 (has links)
Natural Hazards are a risk to buried gas pipeline infrastructure, but these risks are difficult to assess and quantify. This can often lead to the risks not being properly identified by pipeline owners. The risk to pipelines within landslide areas are particularly difficult to assess given the complex nature of landslide movements and the soil-pipeline interaction mechanisms imposing loads on a pipeline. This thesis research examines the relationship between ground movements and strains/stresses in buried pipelines through field measured ground movements and in-situ measured pipe strains/stresses. The pipe stresses and strains are then used to estimate probability of pipeline failure and risk based on RBDA limit states approaches. Within Manitoba Hydro’s pipeline network, three at-risk landslide areas (riverbank and deep river valleys) were selected for detailed studies. A field investigation and monitoring program was undertaken to assess possible sources of load and stresses on pipelines. Soil, ground, and pipe instrumentation were installed at the sites and monitored over a four year period. Monitoring results identified soil near the pipeline does not freeze, and ground movements at valley sites are slow moving (<50 mm/year) landslides. The monitoring results also showed pipe stresses and behaviour were affected by backfilling, changes in river levels, thermal affects, soil-pipe relaxation, and ground movements. Pipe push tests were conducted in conjunction with FEM modelling to examine pipe adhesion and to possible explain the pipe behaviour observed. Several ultimate and serviceability limit states pipe failure modes were assessed using the measured pipe stresses. Statistical analysis was undertaken to calculate the probability of pipeline failure for the various limit states failure modes and compared against limit states targets for several scenarios (backfill loads, initial stress-state of the pipeline, other pipelines within Manitoba Hydro network). Overall, the probability of failure estimates were generally insignificant or low due to a postulated soil-pipe relaxation mechanism which is causing a repeated release in longitudinal pipe stresses as the landslide continues to accumulate ongoing ground movements. Three mechanisms are presented and discussed. The statistical analysis indicate pipelines within Manitoba Hydro’s network may exceed limit states targets for yielding and local buckling depending on the loading scenario and the class of the pipeline within the landslide area. The outcome of the research was used to develop a risk managements system to examine geotechnical hazards within Manitoba Hydro’s pipeline network. Specifically, risks associated with ground movements along natural slopes and at river crossings are examined within the system. / October 2016
570

A numerical study of the axial compressive behavior of a hyperelastic annular seal constrained in a pipe

Bartel, Alix 12 September 2016 (has links)
Elastomer seals are used in a variety of industries that require flow isolation. The characterization of the behavior of these seals remains largely unexplored and hence, this study is focused on simulating and validating the axial-compressive behavior of an annular rubber seal constrained concentrically in a pipe. The elastomer material composing the seal, was experimentally characterized for its mechanical, frictional, and viscoelastic properties and modelled using models developed by Yeoh, Thirion, and Prony respectively. A 2D axisymmetric finite-element model was developed using ANSYS 16 and used alongside the material models to simulate an axial load versus displacement curve, a contact pressure distribution, and a pipe hoop strain gradient. The results for quasi-static loading and viscoelastic effects agreed within 7% and 18% of the experimental results, respectively. It was observed that pipe geometry, rubber chemistry, frictional properties, and viscoelastic effects have significant effect on the compressive behavior of the seal. / October 2016

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