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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.
501

[en] TROPICALIZATION OF THE REVERSE MORTGAGE MODEL: REAL OPTIONS APPROACH / [pt] TROPICALIZAÇÃO DO MODELO DE HIPOTECA REVERSA: ABORDAGEM POR OPÇÕES REAIS

ANDREA PINHEIRO CASTOLDI 03 February 2021 (has links)
[pt] A Hipoteca Reversa é um produto financeiro que pode muito útil para mutuários acima de 60 anos que possuem imóvel próprio, mas não têm renda nem liquidez. Também chamada de Reverse Mortgage, a Hipoteca Reversa é um empréstimo que proporciona liquidez ao mutuário tendo como garantia um ativo imobiliário, que reverte para o banco ao final da sua vida. Por outro lado, esse produto traz riscos para o credor, uma vez que o valor do imóvel poderá sofrer oscilação de preço durante a vigência do empréstimo, e o prazo para a reversão do imóvel dependerá do tempo de vida do mutuário, o que também é incerto. Um dos benefícios da Hipoteca Reversa para o mutuário é que o valor da dívida é limitado ao valor de venda do imóvel dado em garantia. Assim, se o valor do empréstimo exceder o preço do imóvel, devido a uma desvalorização, a dívida estará limitada ao escopo do valor do imóvel. Além disso, em alguns países o mutuário pode optar por rescindir o seu contrato de hipoteca quitando o valor da dívida, o que se torna interessante se este for menor do que o valor do imóvel. Essa característica da Hipoteca Reversa pode ser modelada como uma opção de compra do imóvel dado em garantia ao preço de exercício que é o valor da dívida. O presente estudo analisa o histórico do uso de Hipoteca Reversa no mundo e propõe um modelo de produto mais adequado para as condições brasileiras, onde é feita uma aplicação numérica que aborda diferentes casos e seus resultados, contribuindo para o aumento da compreensão das hipotecas reversas do ponto de vista do consumidor. Por fim, foi avaliado o valor da opção da Hipoteca Reversa no Brasil por meio de uma análise empírica usando o modelo de precificação por Opções Reais. / [en] The Reverse Mortgage is a financial product that can be very useful for borrowers over 60 years old who are homeowners but have neither income nor liquidity. A Reverse Mortgage is a loan that provides liquidity to the borrower with the guarantee of a real estate asset, which reverts to the bank at the end of its life. On the other hand, this product carries risks for the lender, since the value of the property may fluctuate in price during the term of the loan, and the term for the reversal of the property will depend on the life of the borrower, which is also uncertain. One of the benefits of the Reverse Mortgage for the borrower is that the value of the debt is limited to the sale value of the property given as collateral. Thus, if the value of the loan exceeds the price of the property, the debt will be limited to the scope of the property s value. In addition, in some countries, the borrower may choose to terminate his mortgage contract by paying off the debt, which is interesting if it is less than the value of the property. This characteristic of the Reverse Mortgage can be modeled as an option to purchase the property given as a guarantee at the strike price, which is the debt value. The present study analyzes the history of the use of Reverse Mortgage in the world and proposes a product model more suitable for Brazilian conditions, where a numerical application is made that addresses different cases and their results, contributing to an increase in the understanding of the reverse mortgages of the consumer point of view. Finally, the value of the Reverse Mortgage option in Brazil was assessed through an empirical analysis using the Real Options pricing model.
502

Socialarbetares upplevelser av hot och våld : En narrativ studie / Social workers' experience of client violence : A narrative study

Bornudd, Felicia, Bergqvist, Yasmine January 2022 (has links)
The purpose of this narrative study is to highlight social workers' experiences of threats and violence within their profession, as well as the variety of resources to fend off, remedy and manage the risk of threats and violence. The present problem is how threats and violence are underreported, partly due to social workers' views on their own profession and a work climate that might not encourage reporting incidents. Previous studies have shown high prevalence of threats and violence within social work and consequences that follow, such as high levels of stress, leading to burnout. Other studies found that the fear of being exposed to threats and violence can result in self-censorship, thereby limiting autonomy and professional judgment. Through interviews we found that social workers had experienced violence and threats of different sorts, primarily verbal threats. The overall perception was of understanding nature due to injustice that many clients face, resulting in expressions of strong emotions. However, some social workers described their work as characterized by imminent threats, rather than fear of being exposed. The preventing resources provided at the workplace are described as mostly effective and fulfilling of its purpose, while others find that they create unnecessary distance between them and clients. The social workers perceive themselves as fairly prepared for violent or threatening situations, mainly through their education, but emphasize experience over any type of education. They also emphasize the support from colleagues and managers as valuable and important resources. By highlighting the narrative of social workers we hope to bring awareness to this issue and encourage an open dialogue.
503

Modular friction test rig for measuring torque and tension in threaded fasteners / Modulär friktionsrigg för mätning av moment och töjning i gängade fästelement

Afsharian, Reza, Theodoropoulos, Antonios January 2018 (has links)
This report describes the development of a modular friction test rig for threaded fasteners. This device can measure the shank torque and the clamp force during the tightening of threaded bolts, with a size of M3-M14 and clamp length of 30-160mm. The design allows the use of several load and torque cells and the range is up to 100kN clamp load and 200Nm applied torque. The test rig will be used for research purposes by Atlas Copco to determine the frictional characteristics in tightening and will allow the experiments on bolts with several materials, coatings and surface finishes. This report concludes to a design proposal evaluated with analytical methods and a prototype 3D model that demonstrate the working principle of the test rig. The measurements are taken from custom-made sensors that are developed with high standards, are easily interchangeable and can be calibrated individually. In addition, a device is developed to allow the user to change the stiffness of the joint. Finally, a future recommendation is made to allow the measurement of the under-head torque. This proposal is a breakthrough compared to other test rigs, and will assist in verifying the friction measurements and having high precision results. / Denna rapport beskriver utvecklingen av en modulär friktionsprovrigg för gängade fästelement. Den utvecklade enheten kan mäta moment och klämkraft under åtdragning av gängade skruvar, med en storlek mellan M3 och M14 och klämlängd på 30-160mm. Designen möjliggör användning av flera last- och vridmomentceller och intervallet är upp till 100kN klämbelastning och 200Nm påfört vridmoment. Provriggen är en forskningsrigg, och den kommer att användas av Atlas Copco för att bestämma friktionsegenskaperna i åtdragning och möjliggöra experiment på skruvar av olika material, och med olika ytbeläggningar och ytbehandlingar. Denna rapport avslutas med ett designförslag, som utvärderas analytiskt och testprincipen demonstreras med hjälp av en prototyp. Mätningarna tas från skräddarsydda sensorer, som kan kalibreras individuellt och som är enkelt utbytbara. Dessutom är en anordning utvecklad för att tillåta användaren att ändra styvheten hos förbandet. Slutligen ges en rekommendation för en vidareutveckling, som möjliggör mätning av skallmomentet. Detta förslag är ett genombrott jämfört med andra existerande testriggar, och kommer att bidra till att verifiera friktionsmätningarna med hög precision.
504

Multiscale Characterization of Dislocation Development During Cyclic Bending Under Tension in Commercially Pure Titanium

Miller, Nathan R. 12 April 2024 (has links) (PDF)
Continuous bending under tension (CBT) has been shown to increase room temperature elongation-to-failure (ETF) in various sheet metals past that of simple tension (ST). In commercially pure titanium (CP-Ti) Grade 4, up to 3x extended elongation over ST has been achieved. A greater understanding of deformation mechanisms in CBT would allow for its elongation-enhancing effects to be more fully exploited in HCP and other metals, creating potential for new forming strategies. While most of the extended ETF has been attributed to delayed localization via incremental deformation inherent to the CBT process, together with compressive stabilization and relaxation of mechanical strain fields, contributions of microscale components relating to damage evolution, defect structures, and slip system activity intrinsic to the process are also likely to play a role. CBT-induced cyclic bending/unbending stresses combined with applied macroscopic tension create complex through-thickness stress profiles, where differing hardening behavior is expected near the surfaces compared with the middle of the sheet. This work uses high resolution EBSD characterization of geometrically necessary dislocation (GND) density together with X-ray diffraction (XRD)-based evaluations of total dislocation density and in-plane digital image correlation (DIC) to provide an in-depth analysis of through-thickness dislocation development and associated hardening rates throughout the CBT process in CP-Ti Grade 4 sheet metal. It was found that dislocation density is relatively uniform across the sheet at lower cycles, increases in the sheet center at higher cycles, and eventually approaches saturation near failure. Namely, dislocation accumulation occurs more slowly in the ratcheting, bending/unbending portions of the sheet (i.e., near the surfaces) from cyclic load reversals, and develops faster in the central tensile portion, where dislocation density up to 1.43x higher than near the surfaces was observed. The fraction of 〈c+a〉-type dislocations stayed below ~27% within the sheet, decreasing with increased strain, suggesting that the texture evolves such as to favor 〈a〉-type slip. Indications of stronger texture evolution occurring in the ratcheting (cyclic) regions were observed, with central texture resembling that of a sample deformed in ST. High dislocation densities in the sheet center were found to precede significant central void accumulation, concentrating damage away from peak surface stresses, presumably contributing to delayed failure.
505

Model-Based Decision Making Under Uncertainty: Empirical and MachineLearning Strategies for Obtaining Insight with Physical Models andUnparameterized Complexities

Tracy, Jacob January 2022 (has links)
No description available.
506

The Importance of Clinical Examination under General Anesthesia: Improving Parametrial Assessment in Cervical Cancer Patients

Sodeikat, Pauline, Lia, Massimiliano, Martin, Mireille, Horn, Lars-Christian, Höckel, Michael, Aktas, Bahriye, Wolf, Benjamin 26 April 2023 (has links)
Background: Parametrial tumor involvement is an important prognostic factor in cervical cancer and is used to guide management. Here, we investigate the diagnostic value of clinical examination under general anesthesia (EUA) and magnetic resonance imaging (MRI) in determining parametrial tumor spread. Methods: Post-operative pathological findings of 400 patients with primary cervical cancer were compared to the respective MRI data and the results from EUA. The gynecological oncologist had access to the MR images during clinical assessment (augmented EUA, aEUA). Results: Pathologically proven parametrial tumor invasion was present in 165 (41%) patients. aEUA exhibited a higher accuracy than MRI alone (83% vs. 76%; McNemar’s odds ratio [OR] = 2.0, 95%CI 1.25–3.27, p = 0.003). Although accuracy was not affected by tumor size in aEUA, MRI was associated with a lower accuracy in tumors ≥2.5 cm (OR for a correct diagnosis compared to smaller tumors 0.22, p < 0.001). There was also a decrease in specificity when evaluating parametrial invasion by MRI in tumors ≥2.5 cm in diameter (p < 0.0001) compared to smaller tumors (< 2.5 cm). Body mass index had no influence on performance of either method. Conclusions: aEUA has the potential to increase the diagnostic accuracy of MRI in determining parametrial tumor involvement in cervical cancer patients.
507

Computational and Machine Learning-Reinforced Modeling and Design of Materials under Uncertainty

Hasan, Md Mahmudul 05 July 2023 (has links)
The component-level performance of materials is fundamentally determined by the underlying microstructural features. Therefore, designing high-performance materials using multi-scale models plays a significant role to improve the predictability, reliability, proper functioning, and longevity of components for a wide range of applications in the fields of aerospace, electronics, energy, and structural engineering. This thesis aims to develop new methodologies to design microstructures under inherent material uncertainty by incorporating machine learning techniques. To achieve this objective, the study addresses gradient-based and machine learning-driven design optimization methods to enhance homogenized linear and non-linear properties of polycrystalline microstructures. However, variations arising from the thermo-mechanical processing of materials affect microstructural features and properties by propagating over multiple length scales. To quantify this inherent microstructural uncertainty, this study introduces a linear programming-based analytical method. When this analytical uncertainty quantification formulation is not applicable (e.g., uncertainty propagation on non-linear properties), a machine learning-based inverse design approach is presented to quantify the microstructural uncertainty. Example design problems are discussed for different polycrystalline systems (e.g., Titanium, Aluminium, and Galfenol). Though conventional machine learning performs well when used for designing microstructures or modeling material properties, its predictions may still fail to satisfy design constraints associated with the physics of the system. Therefore, the physics-informed neural network (PINN) is developed to incorporate problem physics in the machine learning formulation. In this study, a PINN model is built and integrated into materials design to study the deformation processes of Copper and a Titanium-Aluminum alloy. / Doctor of Philosophy / Microstructure-sensitive design is a high-throughput computational approach for materials design, where material performance is improved through the control and design of microstructures. It enhances component performance and, subsequently, the overall system's performance at the application level. This thesis aims to design microstructures for polycrystalline materials such as Galfenol, Titanium-Aluminum alloys, and Copper to obtain desired mechanical properties for certain applications. The advantage of the microstructure-sensitive design approach is that multiple microstructures can be suggested, which provide a similar value of the design parameters. Therefore, manufacturers can follow any of these microstructure designs to fabricate the materials with the desired properties. Moreover, the microstructure uncertainty arising from the variations in thermo-mechanical processing and measurement of the experimental data is quantified. It is necessary to address the resultant randomness of the microstructure because it can alter the expected mechanical properties. To check the manufacturability of proposed microstructure designs, a physics-informed machine learning model is developed to build a relation between the process, microstructure, and material properties. This model can be used to solve the process design problem to identify the processing parameters to achieve a given/desired microstructure.
508

Mechanistic Study of Under Deposit Corrosion of Mild Steel in Aqueous Carbon Dioxide Solution

Huang, Jin January 2013 (has links)
No description available.
509

The influence of uncertainty and liquidity constraints on liquid asset holdings of credit card revolvers

Bi, Lan 07 October 2005 (has links)
No description available.
510

Ledarskap på distans : En kvalitativ studie om hur ledarskapet har påverkats av covid-19

Norozi, Shadi, Lindström, Ludwig January 2021 (has links)
This work aims to give the reader a deeper understanding of the challenges that arise in the event of forced digital leadership at a distance, as well as what characterizes a good leader during change with an uncertain future where communication takes place at a distance. At the end of 2019, the world was shaken by the covid-19 virus, which was soon classified as a pandemic. To reduce the spread of infection, one of the consequences of the pandemic was that organizations were forced to work remotely. Major changes within organizations needed to take place and managers would now lead their employees digitally at a distance. In this study, six individuals who provide managerial positions / leading roles within different organizations participated in semi-structured interviews in order to answer the study's two research questions. The study has used a qualitative method with a research design in the form of a case study. The study draws on the following theories in leadership; Transformative leadership, Transactional leadership, Situational leadership, Virtual leadership and Leadership under stress. Based on the collected empirical material and the previously mentioned theoretical basis, the authors have created a picture of the challenges that exist in leading at a distance and what characterizes a good leader. The study concluded that one of the biggest challenges in digital leadership at a distance is the lack of body language, which in turn affects communication. There were also challenges socially as it was considered more difficult to hold more relaxed and informal conversations when communication takes place virtually. In the study, the authors also concluded that good leadership during change is characterized by trust and a focus on the leader to see each individual as one and to give that person the best conditions in order to perform.

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