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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.
151

Numerical Studies On Ductile Fracture Of Pressure Sensitive Plastic Solids

Subramanya, H Y 01 1900 (has links)
Experimental studies have shown that the yield strength of many important engineering materials such as polymers, ceramics and metallic glasses is dependent on hydrostatic stress. In addition, these materials may also exhibit plastic dilatancy. These deviations from the assumptions of classical plasticity theories have also been observed for some metallic alloys, although to a lesser extent compared to non-metals. In pressure independent plastic solids, it has been found that the level of crack tip constraint can affect the near-tip stress and deformation fields and hence the fracture resistance. The objective of the present work is to study the effects of pressure sensitive yielding, plastic dilatancy and constraint loss on the ductile fracture processes under mode-I conditions. Further, the three-dimensional (3D) structure of elastic-plastic near-crack front fields in a pressure independent plastic solid under mixed mode (combined modes I and II) loading is also examined. A finite element study of 3D crack tip fields in pressure sensitive plastic solids under mode-I, small scale yielding (SSY) conditions is first carried out. The material is assumed to obey a small strain, Extended Drucker-Prager (EDP)yield criterion. The roles of pressure sensitive yielding, plastic dilatancy and yield locus shape on the 3D plastic zone development and near-crack front fields are systematically investigated. It is found that while pressure sensitivity leads to a significant drop in the hydrostatic stress all along the 3D crack front, it enhances the plastic strain and crack opening displacements. However, plastic incompressibility results in elevation of both near-tip hydrostatic stress and notch opening. The implications of these observations on micro-void growth and interaction near a notch tip are studied in detail subsequently. The effects of constraint loss on void growth near a notch tip under mode-I loading in materials exhibiting pressure sensitive yielding and plastic dilatancy are investigated by performing large deformation elastic-plastic finite element analyses. To this end, two-dimensional (2D)plane strain and 3Dmodified boundary layer formulations are employed by prescribing the elastic K-T field as remote boundary conditions. The results are generated for different combinations of K (or J ) and T -stress. The material is assumed to obey a finite strain, EDP yield condition. The distributions of hydrostatic stress and plastic strain in the ligament connecting the notch and a nearby void (cylindrical or spherical) as well as the growth of the notch and the void are studied. The results show that void growth with respect to J is enhanced due to pressure sensitivity, and more so when the plastic flow is non-dilatational, which corroborates with the trends exhibited by the 3D crack tip fields. However, the evolution of ductile fracture processes like void growth, plastic strain localization and ligament length reduction with respect to J is retarded in the case of spherical voids. Further, irrespective of pressure sensitivity, loss of crack tip constraint can significantly slow down void growth. The effects of pressure sensitive yielding and plastic dilatancy on near-tip void growth and multiple void interaction mechanisms in single edge notched bend (SENB) and center cracked tension (CCT) specimens which display high and low constraint levels, respectively, are investigated next. It is observed that the latter mechanism which is favored by high initial porosity is further accelerated by pressure sensitive yielding and high constraint. The predicted resistance curves based on a simple void coalescence mechanism show enhancement in fracture resistance when constraint level is low and when pressure sensitivity is suppressed. Finally, detailed elastic-plastic finite element simulations are carried out using a boundary layer (SSY) formulation to investigate the 3D nature of near-crack front fields in a von Mises solid under mixed mode (combined modes I and II)loading. The plastic zones and radial, angular and thickness variations of the stresses are studied corresponding to different levels of remote elastic mode mixity and applied load, as measured by the plastic zone size with respect to the plate thickness. The 3D results are compared with those obtained from 2D simulations and asymptotic solutions to establish the validity of 2D plane stress and plane strain approximations near a crack front. It is found that, in general, plane stress conditions prevail at a distance from the crack front exceeding half the plate thickness, although it could be slightly smaller for mode-II predominant loading.
152

Photo-crosslinked Surface Attached Thin Hydrogel Layers

Pareek, Pradeep 06 April 2005 (has links) (PDF)
Stimuli sensitive polymers and hydrogels respond with large property changes to small physical and chemical stimuli (e.g. temperature, pH, ionic strength). The bulk behavior of these polymers is widely studied and they show an isotropic swelling. However, thin hydrogel layers of polymers on a substrate show a swelling behavior, which is constrained in some way. Therefore, size, confinement, patternability, response time and transition temperature of thin hydrogel layers are the most important parameters in technological applications and this study focuses on the investigation of these above-mentioned parameters. The aim of this study involves synthesis, characterization and application of thin photo-crosslinked hydrogel layers. Dimethylmaleimide (DMI) moiety was incorporated in the polymers chains and was used to introduce photo-crosslinking by [2+2] cyclodimerization reaction in the presence of UV irradiation. The following photo-crosslinkers based on DMI group were synthesized ? - Acrylate photo-crosslinker (DMIAm) - Acrylamide photo-crosslinker (DMIAAm) - Polyol photo-crosslinker (DMIPA, DMIPACl) The conventional free radical polymerization of above listed photo-crosslinker with its respective monomer resulted in formation of photo-crosslinkable polymers of (a) HEMA, (b) DMAAm, (c) NIPAAm/DMAAm, (d) NIPAAm/Cyclam. The properties of these polymers were investigated by NMR, UV-VIS spectroscopy, GPC and SPR. Thin hydrogel layers were prepared by spin coating on gold-coated LaSFN9 glass. The covalent attachment to the surface was achieved through an adhesion promoter. Swelling behavior of the thin polymer layers was thoroughly investigated by Surface Plasmon Resonance (SPR) Spectroscopy and Optical Waveguide Spectroscopy (OWS). SPR and OWS gave a wide range of information regarding the film thickness, swelling ratio, refractive index, and volume degree of swelling of the thin hydrogel layer. For hydrophilic photo-crosslinked hydrogel layers of HEMA and DMAAm, it was observed that the volume degree of swelling was independent of temperature changes but was dependent on the photo-crosslinker mol-% in the polymer. These surface attached thin hydrogel layer exhibited an anisotropic swelling. For NIPAAm photo-crosslinked hydrogel layers with DMAAm as a hydrophilic monomer, it was observed that both transition temperature (Tc) and volume degree of swelling increases with increase in the mol-% of DMAAm. To study the effect of film thickness on Tc and volume degree of swelling, hydrogels with wide range of film thickness were prepared and investigated by SPR. These results provided vital information on the swelling behavior of surface attached hydrogel layer and showed the versatility of SPR instrument for studying thin hydrogel layers. Later part of project involved synthesis of multilayer hydrogel assembly involving a thermoresponsive polymer and a hydrophilic polymer. The combination of two layers with photo-crosslinkable DMAAm polymer as base layer and photo-crosslinkable NIPAAm polymer as top layer formulate a multilayer assembly where, the base layer only swells in response to temperature and the top layer shows temperature dependent swelling. Photo-crosslinked hydrogel layers of NIPAAm, DMAAm and HEMA shows a high-resolution patterns when irradiated by UV light through a chromium mask. At last this study focused on an important application of these hydrogel layers for cell attachment processes. Cell growth, proliferation and spreading shows a biocompatible nature of these hydrogel surfaces. Such thermoresponsive photo-crosslinkable multilayer structure forms bases for future projects involving their use in actuator material and cell-attachment processes.
153

Engineering Characteristics of Sensitive Marine Clays - Examples of Clays in Eastern Canada

Nader, Athir 28 February 2014 (has links)
Sensitive marine clay in Ottawa is a challenging soil for geotechnical engineers. This type of clay behaves differently than other soils in Canada or other parts of the world. They also have different engineering characteristic values in comparison to other clays. Cone penetration testing in sensitive marine clays is also different from that carried out in other soils. The misestimation of engineering characteristics from cone penetration testing can result. Temperature effects have been suspected as the reason for negative readings and erroneous estimations of engineering characteristics from cone penetration testing. Furthermore, the applicability of correlations between cone penetration test (CPT) results and engineering characteristics is ambiguous. Moreover, it is important that geotechnical engineers who need to work with these clays have background information on their engineering characteristics. This thesis provides comprehensive information on the engineering characteristics and behaviour of sensitive marine clays in Ottawa. This information will give key information to geotechnical engineers who are working with these clays on their behaviour. For the purpose of this research, fifteen sites in the Ottawa area are taken into consideration. These sites included alternative technical data from cone and standard penetration tests, undisturbed samples, field vanes, and shear wave velocity measurements. Laboratory testing carried out for these sites has resulted in acquiring engineering parameters of the marine clay, such as preconsolidation pressure, overconsolidation ratio, compression and recompression indexes, secondary compression index, coefficient of consolidation, hydraulic conductivity, clay fraction, porewater chemistry, specific gravity, plasticity, moisture content, unit weight, void ratio, and porosity. This thesis also discusses other characteristics of sensitive marine clays in Ottawa, such as their activity, sensitivity, structure, interface shear behaviour, and origin and sedimentation. Furthermore, for the purpose of increasing local experience with the use of cone and ball penetrometers in sensitive marine clays in Ottawa, three types of penetrometer tips are used in the Canadian Geotechnical Research Site No. 1 located in south-west Ottawa: 36 mm cone tip, and 40 mm and 113 mm ball tips. The differences in their response in sensitive marine clays will be discussed. The temperature effects on the penetrometer equipment are also studied. The differences in the effect of temperature on these tips are discussed. Correlations between the penetrometer results and engineering characteristics of Ottawa's clays are verified. The applicability of correlations between the testing results and engineering characteristics of sensitive marine clays in Ottawa is also presented in this thesis. Two correlations from the Canadian Foundation Engineering Manual are examined. One of these correlations is between the N60 values from standard penetration testing and undrained shear strength. The other correlation is between the shear wave velocity measurement and site class. Temperature corrections are suggested and discussed for penetrometer equipment according to laboratory calibrations. The significance of the effects due to radical temperature changes in Canada and Ottawa is discussed. Some of the main findings from this research are as follows. • The Canadian Foundation Engineering Manual presents a correlation between standard penetration tests (SPTs) and the undrained shear strength of soils. This relationship may not be applicable to sensitive marine clays in Ottawa. • Another correlation between the site class, shear wave velocity, and undrained shear strength is presented by this same manual which may not be applicable to sensitive marine clays in Ottawa. • The rotation rate for field vane testing as recommended by ASTM D2573 is slow for sensitive marine clays in Ottawa. • Correction factors applied to undrained shear strength from laboratory vane tests may not result in comparable values with the undrained shear strength obtained by using field vane tests. • Loading schemes in consolidation or oedometer testing may affect the quality of the targeted results. • Temperature corrections should be applied to penetrometer recordings to compensate for the drift in the results of these recordings due to temperature changes. • The secondary compression index to compression index ratio presented in the literature may not be the value obtained from this research.
154

Analyse des pointeurs pour le langage C / Points to analysis for the C language

Mensi, Amira 24 June 2013 (has links)
Les analyses statiques ont pour but de déterminer les propriétés des programmes au moment de la compilation. Contrairement aux analyses dynamiques, le comportement exact du programme ne peut être connu. Par conséquent, on a recours à des approximations pour remédier à ce manque d'information. Malgré ces approximations, les analyses statiques permettent des optimisations et des transformations efficaces pour améliorer les performances des programmes. Parmi les premières analyses du processus d'optimisation figure l'analyse des pointeurs. Son but est d'analyser statiquement un programme en entrée et de fournir en résultat une approximation des emplacements mémoire vers lesquels pointent ses variables pointeurs. Cette analyse est considérée comme l'une des analyses de programmes les plus délicates et l'information qu'elle apporte est très précieuse pour un grand nombre d'autres analyses clientes. En effet, son résultat est nécessaire à d'autres optimisations, comme la propagation de constante, l'élimination du code inutile, le renommage des scalaires ainsi que la parallélisation automatique des programmes. L'analyse des pointeurs est très nécessaire pour l'exploitation du parallélisme présent dans les applications scientifiques écrites en C. Ceci est dû au fait que les tableaux, très présents dans ce type d'applications, sont accédés via les pointeurs. Il devient nécessaire d'analyser les dépendances entre les éléments de tableau dans le but de paralléliser les boucles. Le langage C présente beaucoup de difficultés lors de son analyse par la liberté qu'il offre aux utilisateurs pour gérer et manipuler la mémoire par le biais des pointeurs. Ces difficultés apparaissent par exemple lors de l'accès aux tableaux par pointeurs, l'allocation dynamique (via «malloc») ainsi que les structures de données récursives. L'un des objectifs principaux de cette thèse est de déterminer les emplacements mémoire vers lesquels les pointeurs pointent. Ceci se fait en assurant plusieurs dimensions comme : - la sensibilité au flot de contrôle, c'est-à-dire la mise à jour des informations d'un point programme à un autre ; - la non-sensibilité au contexte, c'est-à-dire l'utilisation de résumés au lieu de l'analyse du corps de la fonction à chaque appel ; - la modélisation des champs pointeurs des structures de données agrégées, dans laquelle chaque champ représente un emplacement mémoire distinct. D'autres aspects sont pris en compte lors de l'analyse des programmes écrits en C comme la précision des emplacements mémoire alloués au niveau du tas, l'arithmétique sur pointeurs ou encore les pointeurs vers tableaux. Notre travail permet l'amélioration des résultats des analyses clientes et en particulier il permet la parallélisation des boucles lorsqu'on accède aux éléments de tableaux via les pointeurs, la détection de code inutile ou le calcul du graphe de dépendances. Il est implémenté dans le compilateur parallélliseur PIPS (Parallélisation Interprocédurale de Programmes Scientifiques) et permet d'analyser, en particulier, les applications scientifiques de traitement du signal tout en assurant une analyse intraprocédurale précise et une analyse interprocédurale efficace via les résumés. / Static analysis algorithms strive to extract the information necessary for the understanding and optimization of programs at compile time. The potential values of the variables of type pointer are the most difficult information to determine. This information is often used to assess if two pointers are potential aliases, i.e. if they can point to the same memory area. An analysis of pointers, also called points-to analysis, may provide more precision to other analyses such as constant propagation, analysis of dependencies or analysis of live variables. The analysis of pointers is very important for the exploitation of parallelism in scientific C programs since the most important structures they manipulate are arrays, which are typically accessed by pointers. It is necessary to analyse the dependencies between arrays in order to exploit the parallelism between loops. C language is very hard to analyse since it allows to users to manipulate the memory through pointers. These difficulties arise for example when accessing arrays by pointers, dynamic allocation (via "malloc") and recursive data structures. Points-to analysis may also attempt to handle recursive data structures and other structures that are accessed by pointers. This work provides a points-to analysis which is : - flow-sensitive, by taking into account the order of execution of instructions ; - field-sensitive, since structure fields are treated as individual locations ; - context-insensitive, because functions summaries are computed to avoid re-analyzing functions bodies. Other issues such as heap modeling, pointer arithmetics and pointers to arrays are also taken into account while analyzing C programs. Our intraprocedural analysis provides precise results to client analyses, in particular it allows parallelization when accessing the array elements loops via pointers, detecting useless code or computing the dependency graph. while our interprocedural one allows to propagate them efficiently. Our work is implemented within the PIPS (Parallélisation Interprocédurale de Programmes Scientifiques) parallelizer, a framework designed to analyze, optimize and parallelize scientific and signal processing applications. Keywords : static analysis, points-to analysis, flow-sensitive, context-insensitive, field-sensitive.
155

Dispersion Characteristics of One-dimensional Photonic Band Gap Structures Composed of Metallic Inclusions

Khodami, Maryam January 2012 (has links)
An innovative approach for characterization of one dimensional Photonic Band Gap structures comprised of metallic inclusions (i.e. subwavelength dipole elements or resonant ring elements) is presented. Through an efficient S- to T-parameters conversion technique, a detailed analysis has been performed to investigate the variation of the dispersion characteristics of 1-D PBG structures as a function of the cell element configuration. Also, for the first time, the angular sensitivity of the structure has been studied in order to obtain the projected band diagrams for both TE and TM polarizations. Polarization sensitivity of the subwavelength cell element is exploited to propose a novel combination of elements which allows achieving PBGs with simultaneous frequency and polarization selectivity. The proposed approach demonstrates that the dispersion characteristic of each orthogonal polarization can be independently adjusted with dipole elements parallel to that same polarization. Generally, the structure has potential applications in orthomode transducer, and generally whenever the polarization of the incoming signal is to be used as a means of separating it from another signal in the same frequency band that is of orthogonal polarization. The current distribution and the resonance behavior of the ring element is studied and the effect of resonance on dispersion characteristics of 1-D PBGs composed of rings is investigated for the first time, for both individual and coupled rings. Interestingly, it is observed that 1-D PBG composed of resonant elements consistently has a bandgap around the resonant frequency of the single layer structure.
156

Engineering Characteristics of Sensitive Marine Clays - Examples of Clays in Eastern Canada

Nader, Athir January 2014 (has links)
Sensitive marine clay in Ottawa is a challenging soil for geotechnical engineers. This type of clay behaves differently than other soils in Canada or other parts of the world. They also have different engineering characteristic values in comparison to other clays. Cone penetration testing in sensitive marine clays is also different from that carried out in other soils. The misestimation of engineering characteristics from cone penetration testing can result. Temperature effects have been suspected as the reason for negative readings and erroneous estimations of engineering characteristics from cone penetration testing. Furthermore, the applicability of correlations between cone penetration test (CPT) results and engineering characteristics is ambiguous. Moreover, it is important that geotechnical engineers who need to work with these clays have background information on their engineering characteristics. This thesis provides comprehensive information on the engineering characteristics and behaviour of sensitive marine clays in Ottawa. This information will give key information to geotechnical engineers who are working with these clays on their behaviour. For the purpose of this research, fifteen sites in the Ottawa area are taken into consideration. These sites included alternative technical data from cone and standard penetration tests, undisturbed samples, field vanes, and shear wave velocity measurements. Laboratory testing carried out for these sites has resulted in acquiring engineering parameters of the marine clay, such as preconsolidation pressure, overconsolidation ratio, compression and recompression indexes, secondary compression index, coefficient of consolidation, hydraulic conductivity, clay fraction, porewater chemistry, specific gravity, plasticity, moisture content, unit weight, void ratio, and porosity. This thesis also discusses other characteristics of sensitive marine clays in Ottawa, such as their activity, sensitivity, structure, interface shear behaviour, and origin and sedimentation. Furthermore, for the purpose of increasing local experience with the use of cone and ball penetrometers in sensitive marine clays in Ottawa, three types of penetrometer tips are used in the Canadian Geotechnical Research Site No. 1 located in south-west Ottawa: 36 mm cone tip, and 40 mm and 113 mm ball tips. The differences in their response in sensitive marine clays will be discussed. The temperature effects on the penetrometer equipment are also studied. The differences in the effect of temperature on these tips are discussed. Correlations between the penetrometer results and engineering characteristics of Ottawa's clays are verified. The applicability of correlations between the testing results and engineering characteristics of sensitive marine clays in Ottawa is also presented in this thesis. Two correlations from the Canadian Foundation Engineering Manual are examined. One of these correlations is between the N60 values from standard penetration testing and undrained shear strength. The other correlation is between the shear wave velocity measurement and site class. Temperature corrections are suggested and discussed for penetrometer equipment according to laboratory calibrations. The significance of the effects due to radical temperature changes in Canada and Ottawa is discussed. Some of the main findings from this research are as follows. • The Canadian Foundation Engineering Manual presents a correlation between standard penetration tests (SPTs) and the undrained shear strength of soils. This relationship may not be applicable to sensitive marine clays in Ottawa. • Another correlation between the site class, shear wave velocity, and undrained shear strength is presented by this same manual which may not be applicable to sensitive marine clays in Ottawa. • The rotation rate for field vane testing as recommended by ASTM D2573 is slow for sensitive marine clays in Ottawa. • Correction factors applied to undrained shear strength from laboratory vane tests may not result in comparable values with the undrained shear strength obtained by using field vane tests. • Loading schemes in consolidation or oedometer testing may affect the quality of the targeted results. • Temperature corrections should be applied to penetrometer recordings to compensate for the drift in the results of these recordings due to temperature changes. • The secondary compression index to compression index ratio presented in the literature may not be the value obtained from this research.
157

Shock diffraction phenomena and their measurement

Quinn, Mark Kenneth January 2013 (has links)
The motion of shock waves is important in many fields of engineering and increasingly so with medical applications and applications to inertial confinement fusion technologies. The flow structures that moving shock waves create when they encounter a change in area is complex and can be difficult to understand. Previousresearchers have carried out experimental studies and many numerical studies looking at this problem in more detail. There has been a discrepancy between numerical and experimental work which had remained unanswered. One of the aims of this project is to try and resolve the discrepancy between numerical and experimental work and try to investigate what experimental techniques are suitable for work of this type and the exact way in which they should be applied. Most previous work has focused on sharp changes in geometry which induce immediate flow separation. In this project rounded corners will also be investigated and the complex flow features will be analyzed.Two geometries, namely a sharp 172 degree knife-edge and a 2.8 mm radius rounded corner will be investigated at three experimental pressure ratios of 4, 8 and 12 using air as the driver gas. This yields experimental shock Mach numbers of 1.28, 1.46 and 1.55. High-speed schlieren and shadowgraph photography with varying levels of sensitivity were used to qualitatively investigate the wave structures. Particle image velocimetry (PIV), pressure-sensitive paint (PSP) and traditional pressure transducers were used to quantify the flow field. Numerical simulations were performed using the commercial package Fluent to investigate the effect of numerical schemes on the flow field produced and for comparison with the experimental results. The sharp geometry was simulated successfully using an inviscid simulation while the rounded geometry required the addition of laminar viscosity. Reynolds number effects will be only sparsely referred to in this project as the flows under investigation show largely inviscid characteristics. As the flow is developing in time rather than in space, quotation of a distance-based Reynolds number is not entirely appropriate; however, Reynolds number based on the same spatial location but varying in time will be mentioned. The density-based diagnostics in this project were designed to have a depth of field appropriate to the test under consideration. This approach has been used relatively few times despite its easy setup and significant impact on the results. This project contains the first quantative use of PIV and PSP to shock wave diffraction. Previous studies have almost exclusively used density-based diagnostics which, although give the best impression of the flow field, do not allow for complete analysis and explanation of all of the flow features present. PIV measurements showed a maximum uncertainty of 5% while the PSP measurements showed an uncertainty of approximately 10%.The shock wave diffraction process, vortex formation, shear layer structure, secondary and even tertiary expansions and the shock vortex interaction were investigate. The experimental results have shown that using one experimental technique in isolation can give misleading results. Only by using a combination of experimental techniques can we achieve a complete understanding of the flow field and draw conclusions on the validity of the numerical results. Expanding the range of the experimental techniques currently in use is vital for experimental aerodynamic testing to remain relevant in an industry increasingly dominated by numerical research. To this end, significant research work has been carried out on extending the range of the PSP technique to allow for the capture of shock wave diffraction, one of the fastest transient fluid processes, and for applications to low-speed flow (< 20 ms−1).
158

Computational Prediction of Flow and Aerodynamic Characteristics for an Elliptic Airfoil at Low Reynolds Number

Chitta, Varun 11 August 2012 (has links)
Lifting surfaces of unmanned aerial vehicles (UAV) are often operated in low Reynolds number (Re) ranges, wherein the transition of boundary layer from laminar-to-turbulent plays a more significant role than in high-Re aerodynamics applications. This poses a challenge for traditional computational fluid dynamics (CFD) simulations, since typical modeling approaches assume either fully laminar or fully turbulent flow. In particular, the boundary layer state must be accurately predicted to successfully determine the separation behavior which significantly influences the aerodynamic characteristics of the airfoil. Reynolds-averaged Navier-Stokes (RANS) based CFD simulations of an elliptic airfoil are performed for time-varying angles of attack, and results are used to elucidate relevant flow physics and aerodynamic data for an elliptic airfoil under realistic operating conditions. Results are also used to evaluate the performance of several different RANS-based turbulence modeling approaches for this class of flowfield.
159

[pt] DETECÇÃO DE CONTEÚDO SENSÍVEL EM VIDEO COM APRENDIZADO PROFUNDO / [en] SENSITIVE CONTENT DETECTION IN VIDEO WITH DEEP LEARNING

PEDRO VINICIUS ALMEIDA DE FREITAS 09 June 2022 (has links)
[pt] Grandes quantidades de vídeo são carregadas em plataformas de hospedagem de vídeo a cada minuto. Esse volume de dados apresenta um desafio no controle do tipo de conteúdo enviado para esses serviços de hospedagem de vídeo, pois essas plataformas são responsáveis por qualquer mídia sensível enviada por seus usuários. Nesta dissertação, definimos conteúdo sensível como sexo, violencia fisica extrema, gore ou cenas potencialmente pertubadoras ao espectador. Apresentamos um conjunto de dados de vídeo sensível para classificação binária de vídeo (se há conteúdo sensível no vídeo ou não), contendo 127 mil vídeos anotados, cada um com seus embeddings visuais e de áudio extraídos. Também treinamos e avaliamos quatro modelos baseline para a tarefa de detecção de conteúdo sensível em vídeo. O modelo com melhor desempenho obteve 99 por cento de F2-Score ponderado no nosso subconjunto de testes e 88,83 por cento no conjunto de dados Pornography-2k. / [en] Massive amounts of video are uploaded on video-hosting platforms every minute. This volume of data presents a challenge in controlling the type of content uploaded to these video hosting services, for those platforms are responsible for any sensitive media uploaded by their users. There has been an abundance of research on methods for developing automatic detection of sensitive content. In this dissertation, we define sensitive content as sex, extreme physical violence, gore, or any scenes potentially disturbing to the viewer. We present a sensitive video dataset for binary video classification (whether there is sensitive content in the video or not), containing 127 thousand tagged videos, Each with their extracted audio and visual embeddings. We also trained and evaluated four baseline models for the sensitive content detection in video task. The best performing model achieved 99 percent weighed F2-Score on our test subset and 88.83 percent on the Pornography-2k dataset.
160

Understanding Liveability in Danish Urban Water Management &amp; Planning: A study of implementing the principles of Water Wise Cities in Marienlyst / Att förstå “liveability” inom danskt urbant dagvattenhantering- och planering: En studie om implementeringen av principerna för Water Wise Cities i Marienlyst

Gustavsson, Mikael January 2023 (has links)
This thesis investigates the implementation of new urban water management and planningapproaches in Denmark, with a specific focus on integrating solutions for extreme rainfallevents and enhancing livability. The study explores the Principles of Water Wise Cities as aframework for incorporating these aspects through Water Sensitive Urban Designs (WSUD).The aim is to provide a clearer understanding of the implementation of Water Wise Cities andthe role of livability in the context of urban water. In order to investigate the aim, the research employs a document analysis of two planningdocuments for Marienlyst, an urban development project in Aarhus Municipality, Denmark.The findings highlight the prevalence of Water Wise Cities through WSUD in Danish urbanwater management. However, the analysis of Marienlyst reveals fragmented integration ofWSUD solutions, lacking the multifunctionality observed in other examples, calling for aholistic and systematic approach to planning that better integrates urban water managementsolutions.  The thesis emphasizes the need to expand the understanding of livability beyond recreation inMarienlyst, to encompass broader implications of enhancing livability through water. It arguesfor comprehensive integration of livability in planning processes to foster resilient and inclusiveurban and community development. The limitations of a top-down approach in conceptualizinglivability are underscored, emphasizing the importance of participatory processes thatincorporate local knowledge. The thesis also addresses the vague nature of the livabilityconcept, advocating for critical engagement and robust integration into planning processes tocreate sustainable and equitable urban environments. In conclusion, this thesis highlights the necessity of a holistic and participatory approach inurban water management, integrating innovative solutions for extreme rainfall events andenhancing livability. The findings contribute to the existing knowledge on urban watermanagement and underscore the ongoing importance of research and development for thecreation of resilient and livable cities. / Denna avhandling undersöker implementeringen av nya metoder för hantering och planeringav vatten i urbana områden i Danmark, med särskilt fokus på att integrera lösningar för extremaregnfall och skapa en bättre förståelse för konceptet ”liveability”. Studien utforskar principernaför Water Wise Cities som en ram för att inkorporera dessa aspekter genom Water SensetiveUrban Design (WSUD). Syftet är att ge en tydligare förståelse för implementeringen av WaterWise Cities och undersöka vilken roll ”liveability” erhåller inom dansk samhällsplanering. För att undersöka syftet använder forskningen en dokumentanalys av två planeringsdokumentför Marienlyst, ett stadsutvecklingsprojekt i Aarhus kommun, Danmark. Resultaten belyserförekomsten av Water Wise Cities genom diverse förslag som främjar implementeringen avWSUD i Marienlyst. Men analysen av Marienlyst avslöjar en fragmenterad integration avWSUD-lösningar som saknar den multifunktionalitet som observeras i andra exempel, vilketkräver ett holistiskt och systematiskt tillvägagångssätt för planering som bättre integrerarlösningar för stadsförvaltning av vatten. Avhandlingen betonar behovet av att utvidga förståelsen för liveability bortom rekreation iMarienlyst, för att omfatta bredare implikationer av att förbättra boendemiljön genom vatten.Den argumenterar för en omfattande integration av boendemiljön i planeringsprocesser för attfrämja en hållbar och inklusiv samhällsutveckling. Vidare problematiseras även debegränsningarna som tydliggörs med ett toppstyrt tillvägagångssätt vid främjandet avliveability konceptet, där större fokus på medborgardialog som inkorporerar lokal befolkningoch dess kunskap i processen rekommenderas. Avhandlingen problematiserar även den vagadefinitionen av liveability som begrepp och förespråkar därmed ett behov för ett kritisktperspektiv på hur vi tolkar begreppet i planeringsprocesser för att möjliggöra rättvisare urbanamiljöer. Slutligen belyser denna avhandling nödvändigheten av ett holistiskt och deltagandetillvägagångssätt inom hanteringen av vatten, genom att integrera innovativa lösningar förextrema regnfall och förbättra boendemiljön. Resultaten bidrar till den befintliga kunskapen omhanteringen av vatten och understryker den pågående betydelsen av forskning och utvecklingför skapandet av trivsamma och hållbara städer.

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