Mobile crowd sensing is one of the most active areas of research. Participatory sensing is part of it in which participants sense their surroundings and collaborate to accomplish a given task. The participants in reference are smartphones. We focus on location dependent tasks and a problem of role assignment. An existing work on the same de fines three types of roles for the participants: broadcasters, normal participants and location information receiver. The broadcasters and normal participants turn on their GPS while location information receivers rely on broadcasters to compute their position. The existing work provides a centralized approach which uses greedy algorithm for role assignment. We propose a sorting based algorithm which minimizes 12-25% of the time for medium and large datasets. We also modify the energy model to minimize power consumption of devices. For this we provide a scheme so that only few devices turn on cellular network to contact server as cellular network consumes considerable energy of smartphones. In the existing approach if new devices join the region then they cannot participate in the ongoing sensing task until server assigns them role during the next localization phase. In addition to this, if device leaves the region then its neighbouring devices may minimize energy needs by changing their role. However, in the current work the algorithm is required to run over entire set of participants for each insertion and deletion of participant. We provide an alternative method to allocate roles adaptively to new participants and change roles for the existing devices when some devices leave the region on fly. This helps to minimize over 95-99.9% time for role assignment compared to existing state of work. In addition to this, we have also proposed a distributed approach so that devices are self-capable of assigning role to themselves based on local information. This is fi rst work so far to relieve server from the task of role assignment. Besides proposing a method, we have also taken into account the residual energy of smartphones for assigning the role of broadcaster which has not been considered before. Our algorithm takes 70-85% less time compared to centralized approach but consumes 12-15% more energy as it does not provide optimal set of broadcasters which requires global information. All the work has been validated through extensive experiments using both real and synthetic datasets.

Single Point Incremental Forming (SPIF) is a die-less sheet metal forming method. Because SPIF does not use custom tooling, this process allows for parts to be made at low cost and short lead times. In this thesis electric current is applied through the tool to alter the formability of samples formed with SPIF. The research goal of this work is to determine if formability is effected by resistive heating alone or if there is some formability change due to the current interacting with the material. An apparatus that allows electrical current to be applied through the tool during forming is designed and implemented. A method is also developed to allow the contact area between the tool and sheet to be estimated, with particular focus on developing a method that allows for experimental measurement. The effect of applied current on formability is estimated by evaluating the maximum wall angle that can be formed in a single pass, using a variety of tool sizes and current settings. Using the contact area model to estimate current density, a signicant increase in formability is found at a current density range that agrees with previously published literature on electrically assisted forming of the same material. The results show that across multiple tool sizes, a significant increase in formability is observed when applying a current density (A/mm2) larger than the current threshold density published in the literature. A study is also performed to test the performance of a set of novel tool shapes. By using parabolic tools, it was found that formability can be improved while maintaining low surface roughness. Finally, a series of case studies are presented documenting the production several parts for a variety of design groups and researchers at Queen's University. These case studies provide examples for the uses of SPIF, as well as document the methods used to produce these parts in greater detail than is present in the literature. / Thesis (Ph.D, Mechanical and Materials Engineering) -- Queen's University, 2013-11-29 16:06:51.964

Attention-Deficit/Hyperactivity Disorder (ADHD) is a disorder characterized by a persistent pattern of developmentally inappropriate levels of inattention, hyperactivity, and impulsivity (American Psychiatric Association, 2000). Currently, clinicians typically utilize a multi-method assessment battery focusing on identifying the core symptoms of ADHD. Further, current recommendations for a comprehensive assessment of ADHD require a lengthy and costly evaluation protocol despite a lack of evidence supporting the incremental utility of each method. Assessment strategies exhibiting the strongest evidence of reliability and validity include symptom-based rating scales, empirically-derived rating scales, and structured diagnostic interviews (Pelham, Fabiano, & Massetti, 2005), yet, their review provided limited empirical support for this conclusion. Nonetheless, other reviews have noted the lack of research examining whether each procedure and/or method adds unique information to a diagnosis of ADHD (Johnston & Murray, 2003). In order to fill this gap in the literature, the current study examined the independent and incremental utility of multiple methods and informants in a comprehensive, “gold standard” assessment of ADHD. The sample include 185 children with ADHD (Mage =9.22, SD=.95) and 82 children without ADHD (Mage =9.24, SD=.88). Logistic regressions were used to examine the incremental contribution of each method in the prediction of consensus diagnoses derived by two Ph.D. level experts in the field of ADHD following a review of comprehensive assessment data. This study also examined the clinical utility and efficiency of diagnostic algorithms using the methods demonstrating the greatest statistical association with a diagnosis of ADHD. Finding provided an empirical support for arguments espousing the redundancy of information in a comprehensive assessment. Namely, information collected from a structured diagnostic interview was unable to significantly improve a prediction model including parent and teacher ratings (Block X2-= .91 = .64). Importantly, parent and teacher ratings on a symptom-based scale alone were able to correctly classify 265 of 267 participants. Based on these results, a diagnostic algorithm that was derived utilizing only behavioral rating scales was able to classify correctly all 267 participants. Clinical implications are highlighted and future research directions are discussed.

Este trabalho tem como objetivo apresentar as principais características do processo de estampagem incremental, suas aplicações, vantagens e limitações assim como verificar a sua viabilidade econômica em aplicações industriais. Os resultados obtidos mostram que este processo pode ser aplicado na indústria em fases de desenvolvimento de produtos ou até mesmo para a produção de pequenos lotes de peças. Os principais métodos utilizados na estampagem incremental são o não assistido por matriz, o semi-assistido por matriz e o assistido por matriz. Os parâmetros que tem maiores influências no processo são: a forma e acabamento da ferramenta, a estratégia de conformação, os incrementos durante a conformação, o sistema de fixação e o lubrificante utilizado. Uma comparação entre o processo de estampagem incremental não assistido por matriz e este processo utilizando uma matriz suporte foi realizado com o objetivo de se verificar a precisão dimensional de cada um dos métodos onde foi comprovado que o método assistido por matriz é mais adequado para a fabricação de produtos onde a tolerância dimensional é um requisito importante. Finalmente a viabilidade econômica do processo de estampagem incremental foi realizada e comparada com o processo de estampagem convencional, comprovando que a estampagem incremental é viável economicamente para pequenos lotes de peças. / This work aimed at presenting the main characteristics of the incremental sheet metal forming process, its applications, advantages and disadvantages and limitations as well as verify its economic viability in industrial applications. The obtained results shows that this process can be applied in industry in the product development phase or even in the production of small batches of parts. The main method utilized in the incremental sheet metal forming are dieless forming, semi-support and supported. The parameters that have great influence on the process are: shape and roughness of tool, the tool path, the step down, the holding system and the lubricant used in the forming process. A comparison between the incremental sheet forming with and with out die to support it was carried out aiming at verify the dimensional accuracy of each method. The method with a die to support it was proved to be is more appropriate to fabricate products where the dimensional accuracy is a important requirement. Finally, the economic viability analysis of the incremental sheet metal forming process were carried out and compared with the conventional stamping process, proving that the incremental sheet metal forming is economically feasible for small batches of pieces.

Cette thèse traite de la modélisation micromécanique de composites viscoélastiques via une approche incrémentale(Al) proposée par Lahellec et Suquet (2007). En plus d'être fondée sur un cadre thermodynamique rigoureux, 1' Al permet une résolution du problème local dans l'espace-temps réel (i.e. sans passage dans l'espace de Laplace). Le premier objectif est d'élargir le spectre d'application de I' Al en termes de lois viscoélastiques locales et de microstructures. Le second objectif est de tenter d'introduire au sein de l'AI la prise en compte des effets de couplage entre la viscoélasticité et la température (couplage thermoélastique mais aussi l'échauffement induit par la dissipation viscoélastique). Tout d'abord, I' Al est codée en Python• puis le programme validé pour des lois viscoélastiques linéaires simples, des microstructures et des chargements déjà étudiés dans les travaux de Lahellec et Suquet. Une seconde partie opère une généralisation théorique de l'AI à de multiples variables internes, non nécessairement déviatoriques et des phases non nécessairement isotropes. Les différentes extensions sont validées progressivement par confrontations aux solutions exactes de référence (champs complets) et en particulier l'efficacité de I' Al étendue à traiter des matrices de type Maxwell généralisé (sans et avec déformations volumiques anélastiques). Cette partie se termine par une démonstration concrète de la possible associat on de l'AI à trois schémas d'homogénéisation (Mori-Tanaka, Double Inclusion, schéma de Malekmohammadi et al. (2014)) en vue de traiter diverses morphologies (composites à fibres, à particules, et à copeaux anisotropes de bois lamellés). La dernière partie traite du couplage entre la viscoélasticité et la température au sein de l'AI. Les versions initiale et discrétisée dans le temps du problème hétérogène thermoviscoélastique fortement couplé sont formulées. Puis, plusieurs degrés de couplage sont envisagés selon une approche progressive des difficultés. Le cas du seul couplage thermoélastique est tout d'abord étudié (couplage de la thermique vers la mécanique, sans résolution de l'équation de la cha leur). les estimations obtenues pour plusieurs chargements thermomécaniques imposés à un milieu périodique contenant des fibres élastiques, thermoélastiques puis thermoviscoélastiques,dans une matrice thermoviscoélastique sont confrontées avec succès aux solutions de référence. Enfin, la résolution simultanée de l'équation de la chaleur est abordée en intégrant comme terme source la dissipation viscoélastique au sein de la matrice en plus du terme de couplage thermoélastique, les fibres étant considérées élastiques. Les évolutions de la température et de la réponse globales révèlent des tendances cohérentes. / This study is devoted to the micromechanical modeling of viscoelastic composites using an incremental approach (IA) due to Lahellec and Suquet (2007). ln addition to be based on a rigorous thermodynamic framework, the IA allows solving the heterogeneous viscoelastic problem in the real time domain (i.e. without the Laplace transform). The first aim is to extend the IA application range in terms of local linear viscoelastic laws and microstructures. The second one is to attempt to introduce the coupling effects between the viscoelasticity and the temperature within the IA framework. First, the IA is coded in Python• and the program validated for simple viscoelastic laws, and for microstructures and loading paths already studied in Lahellec and Suquet (2007). The second part focuses on a theoretical generalization of the IA for many internal variables which are not necessarily deviatoric and for anisotropie phases. The resulting estlmates are progressively validated by confrontation to reference so lutions (full -field simulations) and especially the IA ability to deal with matrices described by generalized Maxwell laws (without and with volumetric anelastic strains). This part ends with a demonstration of the possible association of the IA with three linear homogenization schemes (Mori-Tanaka, Lielen's interpolation, scheme of Malekmohammadi et al. (2014)) in order to deal with various morphologies (fiber or part icle reinforced composites, wood strand-based composites). The last part focuses on the coupling between the viscoelasticity and the temperature within the IA framework. The initial and time discretized versions of the strongly coupled local problem are formulated. Then, increasing coupling levels are envisioned for a progressive approach of the solving procedure. The thermoelastic coupling, alone, is first studied (effect of the thermies on mechanics, without solving the heat equation). The resulting estimates for a periodic microstructure with elastic, thermoelastic then thermoviscoelastic fibers, in a thermoviscoelastic matrix are successfully compared to reference solutions. At last, the heat equation is simultaneously solved by taklng into account the viscoelastic dissipation within the matrix as a source term, in addition to the thermoelastic coupling term. The evolutions of the global temperature and response reveal relevant tendencies.

Este trabalho tem como objetivo apresentar as principais características do processo de estampagem incremental, suas aplicações, vantagens e limitações assim como verificar a sua viabilidade econômica em aplicações industriais. Os resultados obtidos mostram que este processo pode ser aplicado na indústria em fases de desenvolvimento de produtos ou até mesmo para a produção de pequenos lotes de peças. Os principais métodos utilizados na estampagem incremental são o não assistido por matriz, o semi-assistido por matriz e o assistido por matriz. Os parâmetros que tem maiores influências no processo são: a forma e acabamento da ferramenta, a estratégia de conformação, os incrementos durante a conformação, o sistema de fixação e o lubrificante utilizado. Uma comparação entre o processo de estampagem incremental não assistido por matriz e este processo utilizando uma matriz suporte foi realizado com o objetivo de se verificar a precisão dimensional de cada um dos métodos onde foi comprovado que o método assistido por matriz é mais adequado para a fabricação de produtos onde a tolerância dimensional é um requisito importante. Finalmente a viabilidade econômica do processo de estampagem incremental foi realizada e comparada com o processo de estampagem convencional, comprovando que a estampagem incremental é viável economicamente para pequenos lotes de peças. / This work aimed at presenting the main characteristics of the incremental sheet metal forming process, its applications, advantages and disadvantages and limitations as well as verify its economic viability in industrial applications. The obtained results shows that this process can be applied in industry in the product development phase or even in the production of small batches of parts. The main method utilized in the incremental sheet metal forming are dieless forming, semi-support and supported. The parameters that have great influence on the process are: shape and roughness of tool, the tool path, the step down, the holding system and the lubricant used in the forming process. A comparison between the incremental sheet forming with and with out die to support it was carried out aiming at verify the dimensional accuracy of each method. The method with a die to support it was proved to be is more appropriate to fabricate products where the dimensional accuracy is a important requirement. Finally, the economic viability analysis of the incremental sheet metal forming process were carried out and compared with the conventional stamping process, proving that the incremental sheet metal forming is economically feasible for small batches of pieces.

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2014. / Submitted by Ana Cristina Barbosa da Silva (annabds@hotmail.com) on 2015-01-28T18:26:42Z No. of bitstreams: 1 2014_FelipeGarciaPereira.pdf: 4233306 bytes, checksum: c11c3d25a0b0b81080a1d7f43247f5a3 (MD5) / Approved for entry into archive by Raquel Viana(raquelviana@bce.unb.br) on 2015-05-15T20:31:12Z (GMT) No. of bitstreams: 1 2014_FelipeGarciaPereira.pdf: 4233306 bytes, checksum: c11c3d25a0b0b81080a1d7f43247f5a3 (MD5) / Made available in DSpace on 2015-05-15T20:31:12Z (GMT). No. of bitstreams: 1 2014_FelipeGarciaPereira.pdf: 4233306 bytes, checksum: c11c3d25a0b0b81080a1d7f43247f5a3 (MD5) / Este trabalho apresenta um estudo do modelo de Chaboche, avaliando sua capacidade em descrever corretamente o encruamento cinemático sob condições de carregamento multiaxial não proporcional. A partir da conclusão de que este modelo subestima o encruamento sob as condições do estudo, o trabalho apresenta uma proposta de modificação da lei de encruamento cinemático, incorporando o parâmetro de não proporcionalidade da evolução da deformação plástica proposto por Tanaka. O novo modelo é avaliado a partir de um conjunto de simulações numéricas que reproduzem ensaios mecânicos relatados na literatura para quatro materiais metálicos: três ligas de aço e uma liga de alumínio. ____________________________________________________________________________________ ABSTRACT / This work presents a study of the Chaboche model, evaluating its ability to accurately describe the kinematic hardening under conditions of nonproportional multiaxial loading. By concluding that this model underestimates the hardening under such condition, this work presents a modification of the kinematic hardening law, incorporating the parameter that measures the nonproportionality of plastic deformation evolution proposed by Tanaka. The new model is evaluated based on a set of numerical simulations which reproduces mechanical tests reported in the literature for four metallic materials: three steel alloys and an aluminum alloy.

Este trabalho tem como objetivo apresentar as principais características do processo de estampagem incremental, suas aplicações, vantagens e limitações assim como verificar a sua viabilidade econômica em aplicações industriais. Os resultados obtidos mostram que este processo pode ser aplicado na indústria em fases de desenvolvimento de produtos ou até mesmo para a produção de pequenos lotes de peças. Os principais métodos utilizados na estampagem incremental são o não assistido por matriz, o semi-assistido por matriz e o assistido por matriz. Os parâmetros que tem maiores influências no processo são: a forma e acabamento da ferramenta, a estratégia de conformação, os incrementos durante a conformação, o sistema de fixação e o lubrificante utilizado. Uma comparação entre o processo de estampagem incremental não assistido por matriz e este processo utilizando uma matriz suporte foi realizado com o objetivo de se verificar a precisão dimensional de cada um dos métodos onde foi comprovado que o método assistido por matriz é mais adequado para a fabricação de produtos onde a tolerância dimensional é um requisito importante. Finalmente a viabilidade econômica do processo de estampagem incremental foi realizada e comparada com o processo de estampagem convencional, comprovando que a estampagem incremental é viável economicamente para pequenos lotes de peças. / This work aimed at presenting the main characteristics of the incremental sheet metal forming process, its applications, advantages and disadvantages and limitations as well as verify its economic viability in industrial applications. The obtained results shows that this process can be applied in industry in the product development phase or even in the production of small batches of parts. The main method utilized in the incremental sheet metal forming are dieless forming, semi-support and supported. The parameters that have great influence on the process are: shape and roughness of tool, the tool path, the step down, the holding system and the lubricant used in the forming process. A comparison between the incremental sheet forming with and with out die to support it was carried out aiming at verify the dimensional accuracy of each method. The method with a die to support it was proved to be is more appropriate to fabricate products where the dimensional accuracy is a important requirement. Finally, the economic viability analysis of the incremental sheet metal forming process were carried out and compared with the conventional stamping process, proving that the incremental sheet metal forming is economically feasible for small batches of pieces.

No description available.

This study evaluated oxygen uptake (VO2), heart rate (HR), and lactate [HLa] responses between the treadmill (TM) and the CardiosquatTM 1650 LETM inclined stepper by StairMasterTM (SM) during constant-load exercise. The slow component of VO2 (SC) was a central variable assessed during exercise. Twenty-two healthy college-aged (18-30) subjects completed an incremental TM and SM exercise test to establish a workload equivalent to 70% VO2peak. Following each incremental test, a 20-minute constant-load exercise bout was performed . Incremental and instant-load exercise bouts were separated by at least 48 hours. The order of the tests were randomized. VO2, HR, and [HLa] were evaluated at 5, 10, 15, and 20-minutes of exercise. Expired gases were analyzed using a Med Graphics CPX/D metabolic cart. Blood samples were analyzed immediately for lactate concentration with an automated lactate analyzer (Yellow Springs Instrument Model 1500 Sport ). A two-way ANOVA with repeated measures was performed on the rate of change between the treadmill and stepper for VO2, HR, and [HLa]. No significant differences were found for any of the response variables (P>0.05). These results suggest at that the same relative workload, the SM does not elicit a more pronounced SC than the TM. Based on these findings, the SM appears to be an appropriate modality of exercise for various clinical populations. / Master of Science