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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.
31

Computational soundness of formal reasoning about indistinguishability and non-malleability of cryptographic expressions

Hajiabadi, Mohammad 24 August 2011 (has links)
Analysis and verification of security protocols are typically carried out in two different models of cryptography: formal cryptography and computational cryptography. Formal cryptography, originally inspired by the work of Dolev and Yao [14], takes an abstract and idealized view of security, and develops its proof techniques based on methods and ideas from logic and theory of programming languages. It makes strong assumptions about cryptographic operations by treating them as perfectly-secure symbolic operations. Computational cryptography, on the other hand, has developed its foundations based on complexity theory. Messages are viewed as bit-strings, and cryptographic operations are treated as actual transformations on bit-strings with certain asymptotic properties.In this thesis, we explore the relation between the Dolev-Yao model and the computational model of public-key cryptography in two contexts: indistinguishability and non-malleability of expressions. This problem in the absence of key-cycles is partially addressed in [20, 21] by Herzog. We adapt our approach to use the co-inductive definition of symbolic security, whose private-key treatment was considered in coinduction, and establish our main results as follow: Using a co-inductive approach, we extend the indistinguishability and non-malleability results of Herzog in the presence of key-cycles. By providing a counter-example, we show that the indistinguishability property in this setting is strictly stronger than the non-malleability property, which gives a negative answer to Herzog's conjecture that they are equivalent. we prove that despite the fact that IND-CCA2 security provides non-malleability in our setting, the same result does not hold for IND-CCA1 security. We prove that, under certain hypothesis, our co-inductive formal indistinguishability is computationally-complete in the absence of key-cycles and with respect to any \emph{length-revealing} encryption scheme. In the presence of key-cycles, we prove that the completeness does not hold even with respect to IND-CPA security. / Graduate
32

Design and Integration of a Dynamic IPT System for Automotive Applications / Projet et intégration d'un système de transfert inductif pour les applications automobiles

Cirimele, Vincenzo 24 February 2017 (has links)
La transmission inductive de puissance (IPT) pour les véhicules électriques est une technologie émergente prometteuse qui semble capable d'améliorer l'acceptation de la mobilité électrique. Au cours des deux dernières décennies, de nombreux chercheurs ont démontré la faisabilité et la possibilité de l'utiliser pour remplacer les systèmes conducteurs classiques pour la charge de la batterie à bord du véhicule. Actuellement de nombreux efforts visent à étendre la technologie IPT vers son utilisation pour la charge pendant le mouvement du véhicule. Cette application, généralement appelée IPT dynamique, vise à surmonter la limite représentée par les arrêts prolongés nécessaires pour la recharge introduisant également la possibilité de réduction de la capacité de la batterie installée à bord du véhicule. Un système IPT est essentiellement basé sur la résonance de deux inducteurs magnétiquement couplés, l'émetteur, placé sur ou sous le sol, et le récepteur, placé sous le plancher du véhicule. La gamme de fréquence de fonctionnement typique pour les applications automobiles va de 20 kHz à environ 100 kHz. Le couplage entre les deux inductances s'effectue à travers un entrefer important, généralement d'environ 10-30 cm. Cette thèse présente les résultats des activités de recherche visant à la création d'un prototype pour l'IPT dynamique orienté vers le transport privé. A partir d'une analyse de l'état de l'art et des projets de recherche en cours dans ce domaine, ce travail présente le développement d'un modèle de circuit capable de décrire les phénomènes électromagnétiques à la base du transfert de puissance et l'interface avec l'électronique de puissance. Les analyses effectuées à travers le modèle développé fournissent la base pour la conception et la mise en œuvre d'un convertisseur dédié à faible coût et efficacité élevée pour l'alimentation du côté transmetteur. Une architecture générale de l'électronique de puissance qui gère le côté récepteur est proposée avec les circuits de protection supplémentaires. Une méthodologie pour la conception intégrée de la structure magnétique est illustrée. Cette méthodologie couvre les aspects de l'interface avec l'électronique de puissance, l'intégration sur un véhicule existant et l'installation sur l'infrastructure routière. Une série d'activités visant à la réalisation d'un site d'essai dédié sont présentées et discutées. En particulier, les activités liées à la création de l'infrastructure électrique ainsi que les questions et les méthodes d'implantation des émetteurs dans le revêtement routier sont présentées. L'objectif final est la création d'une ligne de recharge IPT dédiée de 100 mètres de long. Enfin, une méthodologie d'évaluation de l'exposition humaine est présentée et appliquée à la solution développée. / Inductive power transmission (IPT) for electric vehicles (EVs) is a promising emergent technology that seems able to improve the electric mobility acceptance. In the last two decades many researchers have proved its feasibility and the possibility to use it to replace the common conductive systems for the charge of the on-board battery. Many efforts are currently aimed to extend the IPT technology towards its use for the charge during the vehicle motion. This application, commonly indicated as dynamic IPT, is aimed to overcome the limit represented by the long stops needed for the recharge introducing also the possibility of reducing the battery capacity installed on vehicle. An IPT system is essentially based on the resonance of two magnetically coupled inductors, the transmitter, placed on or under the ground, and the receiver, placed under the vehicle floor. The typical operating frequency range for the EVs application goes from 20 kHz to approximately 100 kHz. The coupling between the two inductors takes place through a large air-gap, usually about 10-30 cm. This thesis presents the results of the research activities aimed to the creation of a prototype for the dynamic IPT oriented to the private transport. Starting from an analysis of the state of the art and the current research projects on this domain, this work presents the development of a circuit model able to describe the electro- magnetic phenomena at the base of the power transfer and the interface with the power electronics. This model provides the information at the base of the design and the implementation of a dedicated low cost-high efficiency H-bridge converter for the supply of the transmitter side. A general architecture of the power electronics that manages the receiver side is proposed together with the additional protection circuits. A methodology for the integrated design of the magnetic structure is illustrated covering the aspects of the matching with the power electronics, the integration on an existing vehicle and the installation on the road infrastructure. A series of activities aimed to the implementation of a dedicated test site are presented and discussed. In particular, the activities related to the creation of the electrical infrastructure and the issues and methods for the embedding of the transmitters in the road pavement are presented. The final goal is the creation of a dedicated IPT charging line one hundred meters long. Finally, a methodology for the assessment of the human exposure is presented and applied to the developed solution.
33

Upplevelser av att använda mobila applikationer för egenvård vid långvarig sjukdom : en litteraturöversikt / Experiences of using mobile applications during self-care for long-term diseases : a review

Fritzson, Annika, Svensson, Jenny January 2016 (has links)
Bakgrund: Behovet av sjukvård ökar internationellt och allt fler av de vårdsökande är personer med långvarig sjukdom. Detta ökar kravet på vården och vårdpersonalen men även på de vårdsökande personerna. Egenvård är ett sätt att hantera detta och tas fram tillsammans med den enskilda personen och sjukvårdspersonalen. Ett nytt verktyg inom egenvård är m-hälsa där appar används som loggbok, övervakning och ett sätt att kommunicera med personer i samma situation och med vårdpersonal. Syfte: Beskriva hur personer med långvarig sjukdom upplever användandet av m- hälsa vid egenvård. Metod: Litteraturöversikt baserad på 14 kvalitativa artiklar funna i databaserna Pubmed, Cinahl, och Medline. Resultat: Deltagarna såg m- hälsa som ett hjälpmedel vid hanteringen av sin långvariga sjukdom. Motivationen till användningen under en längre tid minskade dock och även ökad stress och ångest var förekommande bland användarna. Diskussion: M-hälsa uppfattades till stora delar som en positiv upplevelse då personerna med långvarig sjukdom fick en bättre överblick av sitt tillstånd. De kunde lättare se hur övningar gav resultat i mätvärden och se tidiga varningstecken på en försämring av sitt tillstånd. Det fanns även de som upplevde att m-hälsa skapade ett beroende av tekniken och därmed minskade själv- ständigheten i sin sjukdom. / Background: The need of healthcare is growing all over the world and the amount of people with chronic diseases increases. This causes more pressure on the healthcare and the personnel, but also on the patients. Self-care is a growing phe- nomenon in healthcare; the way to manage self-care is different for everyone and is developed with healthcare personnel and the patient. A new tool used is m-health; in the m-health applications diaries, monitoring, and a way to communicate with other people in the same situation and with healthcare personnel. Aim: Describe how peo- ple with chronic deceases experience m-health during self-care. Method: Literature review based on fourteen articles from the databases; PubMed, Cinahl, and Medline. Result: The attendants saw m-health as a tool for self-care. The motivation was though decreasing during a long-term use and increased feelings of anxiety and stress was describes from some of the users. Discussion: M-health was mostly a positive experience for the attendants and they got a better overview of their disease and early warning signs if the illness was aggra- vating. The downside of m-health was the feeling of being addicted to the technology and that was lowering the feeling of independents.
34

Approche psychodynamique qualitative et comparative des filicides : vers un modèle de causalité pluridimensionnel / A qualitative and comparative psychodynamic study of childmurder : toward a multidimensional pattern of causality

Souillot, Céline 22 June 2012 (has links)
Une revue de la littérature nous permet de mettre en évidence des facteurs sociaux, économiques, culturels, psychiatriques, épidémiologiques, psychodynamiques et intergénérationnels associés au passage à l'acte infanticide. Cependant, ces facteurs sont considérés indépendamment les uns des autres et sont répandus dans la population, sans mener à l'infanticide : ils ne peuvent donc pas être appréhendés comme étant des facteurs de risque de passage à l'acte. Cette recherche vise donc à proposer un modèle de causalité pluridimensionnel de ces meurtres d'enfants. Nous avons dans un premier temps développé une méthodologie qualitative puis une approche comparative, dans un second temps, est apparue indispensable. Nous avons comparé les facteurs et processus en jeu dans le passage à l'acte meurtrier avec un autre sous groupe psychopathologique, des femmes incarcérées pour violences sexuelles sur leur(s) enfant(s), et avec un groupe témoin. Cette approche comparative s'inscrit dans une démarche inductive, à partir des éléments mis en évidence au sein de la population d'étude. Les analyses cliniques ont mis en évidence un certain nombre de facteurs en jeu dans lepassage à l'acte filicide mais ne peuvent pas constituer des facteurs de risques ou de protection d'un passage à l'acte meurtrier à eux seuls. Les approches omparatives ont permis de dessiner un modèle de causalité pluridimensionnel en jeu dans les passages à l'acte filicide : des tableaux cliniques de population à risque VS protégée de passage à l'acte filicide sont proposés en conclusion. / Thanks to a literary review we can highlight social, economic, cultural, psychiatric,epidemiological, psychodynamic and intergenerational factors connected to the committing childmurder. However these factors are considered separately and are widespread in the population without leading to infanticide and that's why they can't be considered as risk factors inducing its perpretation. This survey aims at proposing a multidimensional pattern of causality of these child murders.First, we developed a qualitative methodology but, subsequently a comparative approach seemed absolutely necessary. We compared the factors and the process at stake considering the perpretation of child murder with another psychopathological subgroup composed of women emprisoned for sexual assaults on their children and with a reference group.This comparative approach lies within the scope of inductive processes, starting from the elements spotted among the test population. The clinical analyses revealed some of the factors at stake in the carrying out of child murder but they can't be considered as risk factors or factors leading to murder for themselves. The comparative studies let us sketch a multidimensional causality pattern involved in child murdering: clinical charts comparing populations at risk and protected populations can be consulted at the end of this survey.
35

Soldagem a arco elétrico assistida por aquecimento indutivo localizado

Dutra, William Todendi January 2017 (has links)
Uma das finalidades do pré-aquecimento na soldagem é reduzir a taxa de resfriamento da junta a ser soldada, com consequente minimização da formação de fases frágeis. Esta prática é usualmente realizada em uma região relativamente extensa no entorno da junta, eventualmente causando alterações indevidas nas propriedades mecânicas e metalúrgicas do metal base, além de desperdiçar energia e tempo. Entretanto, o aquecimento localizado na junta também tem a função de auxiliar na fusão do metal base, fazendo com que este alcance temperaturas próximas à fusão do material. Esse pré-aquecimento pode favorecer o aumento da penetração do cordão de solda. Em juntas de chapas mais espessas, pode ser descartada a usinagem de chanfro em alguns casos, e podem ser alcançadas maiores velocidades do processo de soldagem. Desta forma, neste trabalho foi utilizado um equipamento de aquecimento indutivo para aquecer localmente a zona a ser soldada, visando avaliar a microestrutura formada e o perfil de durezas encontrado para os parâmetros variados. Os parâmetros de montagem e de operação foram avaliados quanto à sua influência na geometria do cordão de solda. A utilização do pré-aquecimento se mostrou efetiva na redução da taxa de resfriamento e consequentemente da proporção de fases frágeis e microdureza máxima das juntas. O trabalho mostra que a penetração e largura do cordão de solda foram aumentadas com o aumento do pré-aquecimento, e reduziram com o aumento da velocidade de soldagem, sendo a velocidade de soldagem o fator com maior influência nestas respostas. / One of the purposes of welding preheating is to decrease cooling rate of the joint to be welded, with consequent minimization of brittle phases formation. This practice is usually performed in a relatively large area around the joint, eventually causing undue changes in base metal mechanical and metallurgical properties, beyond to waste energy and time. However, the heat located in the joint also has the function of assisting in the melting of the base metal, so that it reaches temperatures close to the melting point of the material. This preheating may increase the penetration of the weld bead. In thicker plates may be discarded bevel machining in some cases and can be achieved higher welding speeds. Therefore, in this work an inductive heating equipment was used to locally heat the zone to be welded, aiming to evaluate the formed microstructure and the hardness profile found for the varied parameters. The assembly and operating parameters were evaluated for their influence on the geometry of the weld bead. The use of preheating was effective in reducing cooling rates and consequently in the proportion of brittle phases and maximum microhardness of the welded joint. The work shows that penetration and weld bead width increase with the increasing of the preheating, and reduces with the increase in welding speed, being the welding speed the factor with the greatest influence on this responses.
36

IRE: A Framework For Inductive Reverse Engineering

January 2019 (has links)
abstract: Reverse engineering is critical to reasoning about how a system behaves. While complete access to a system inherently allows for perfect analysis, partial access is inherently uncertain. This is the case foran individual agent in a distributed system. Inductive Reverse Engineering (IRE) enables analysis under such circumstances. IRE does this by producing program spaces consistent with individual input-output examples for a given domain-specific language. Then, IRE intersects those program spaces to produce a generalized program consistent with all examples. IRE, an easy to use framework, allows this domain-specific language to be specified in the form of Theorist s, which produce Theory s, a succinct way of representing the program space. Programs are often much more complex than simple string transformations. One of the ways in which they are more complex is in the way that they follow a conversation-like behavior, potentially following some underlying protocol. As a result, IRE represents program interactions as Conversations in order to more correctly model a distributed system. This, for instance, enables IRE to model dynamically captured inputs received from other agents in the distributed system. While domain-specific knowledge provided by a user is extremely valuable, such information is not always possible. IRE mitigates this by automatically inferring program grammars, allowing it to still perform efficient searches of the program space. It does this by intersecting conversations prior to synthesis in order to understand what portions of conversations are constant. IRE exists to be a tool that can aid in automatic reverse engineering across numerous domains. Further, IRE aspires to be a centralized location and interface for implementing program synthesis and automatic black box analysis techniques. / Dissertation/Thesis / Masters Thesis Computer Science 2019
37

Program Evaluation of Crisis Management Service

2013 May 1900 (has links)
Throughout the last three decades there has been a shift in the provision of crisis services from the hospital to the community (Joy, Adams, & Rice, 2007). Further, the needs of individuals experiencing crises differ, making it essential that these community organizations are able to adapt to each client that they serve (Krupa, Stuart, Mathany, Smart, & Chen, 2010). Program evaluations are one way to determine if, and how, best services are being provided. Using a utilization-focused (Patton, 1997) process evaluation (Stufflebeam & Shinkfield, 2007) framework, the purpose of this study was to explore client perspectives on the services that they are receiving from Crisis Management Service (CMS). Semi-structured interviews were conducted with 14 participants based on questions generated with CMS staff support. Using the general inductive approach (Thomas, 2006), transcripts were analyzed and eight dimensions emerged. The results illustrate client experiences with CMS, client perspectives on the care that they are receiving from CMS, and the benefits they are receiving from being involved with CMS. However, the findings also indicate, that participants would like to change some elements of the program (e.g., having more constant support and having more finances). This study provides valuable insight on clients’ perspectives, particularly that of vulnerable clients in crisis situations, an area that is not extensively researched. This research may also benefit individuals in helping professions as it highlights the effects of working from a strength-based model with at-risk individuals, and the need to engage clients in their move to a healthier lifestyle.
38

ModuleInducer: Automating the Extraction of Knowledge from Biological Sequences

Korol, Oksana 14 October 2011 (has links)
In the past decade, fast advancements have been made in the sequencing, digitalization and collection of the biological data. However the bottleneck remains at the point of analysis and extraction of patterns from the data. We have developed a method that is aimed at widening this bottleneck by automating the knowledge extraction from the biological data. Our approach is aimed at discovering patterns in a set of DNA sequences based on the location of transcription factor binding sites or any other biological markers with the emphasis of discovering relationships. A variety of statistical and computational methods exists to analyze such data. However, they either require an initial hypothesis, which is later tested, or classify the data based on its attributes. Our approach does not require an initial hypothesis and the classification it produces is based on the relationships between attributes. The value of such approach is that is is able to uncover new knowledge about the data by inducing a general theory based on basic known rules. The core of our approach lies in an inductive logic programming engine, which, based on positive and negative examples as well as background knowledge, is able to induce a descriptive, human-readable theory, describing the data. An application provides an end-to-end analysis of DNA sequences. A simple to use Web interface accepts a set of related sequences to be analyzed, set of negative example sequences to contrast the main set (optional), and a set of possible genetic markers as position-specific scoring matrices. A Java-based backend formats the sequences, determines the location of the genetic markers inside them and passes the information to the ILP engine, which induces the theory. The model, assumed in our background knowledge, is a set of basic interactions between biological markers in any DNA sequence. This makes our approach applicable to analyze a wide variety of biological problems, including detection of cis-regulatory modules and analysis of ChIP-Sequencing experiments. We have evaluated our method in the context of such applications on two real world datasets as well as a number of specially designed synthetic datasets. The approach has shown to have merit even in situations when no significant classification could be determined.
39

An approach for modelling snowcover ablation and snowmelt runoff in cold region environments

Dornes, Pablo F. 29 June 2009
Reliable hydrological model simulations are the result of numerous complex interactions among hydrological inputs, landscape properties, and initial conditions. Determination of the effects of these factors is one of the main challenges in hydrological modelling. This situation becomes even more difficult in cold regions due to the ungauged nature of subarctic and arctic environments.<p> This research work is an attempt to apply a new approach for modelling snowcover ablation and snowmelt runoff in complex subarctic environments with limited data while retaining integrity in the process representations. The modelling strategy is based on the incorporation of both detailed process understanding and inputs along with information gained from observations of basin-wide streamflow phenomenon; essentially a combination of deductive and inductive approaches. The study was conducted in the Wolf Creek Research Basin, Yukon Territory, using three models, a small-scale physically based hydrological model, a land surface scheme, and a land surface hydrological model. The spatial representation was based on previous research studies and observations, and was accomplished by incorporating landscape units, defined according to topography and vegetation, as the spatial model elements.<p> Comparisons between distributed and aggregated modelling approaches showed that simulations incorporating distributed initial snowcover and corrected solar radiation were able to properly simulate snowcover ablation and snowmelt runoff whereas the aggregated modelling approaches were unable to represent the differential snowmelt rates and complex snowmelt runoff dynamics. Similarly, the inclusion of spatially distributed information in a land surface scheme clearly improved simulations of snowcover ablation. Application of the same modelling approach at a larger scale using the same landscape based parameterisation showed satisfactory results in simulating snowcover ablation and snowmelt runoff with minimal calibration. Verification of this approach in an arctic basin illustrated that landscape based parameters are a feasible regionalisation framework for distributed and physically based models. In summary, the proposed modelling philosophy, based on the combination of an inductive and deductive reasoning, is a suitable strategy for reliable predictions of snowcover ablation and snowmelt runoff in cold regions and complex environments.
40

Detection of Perfectly-conducting Targets with Airborne Electromagnetic Systems

Smiarowski, Adam 31 August 2012 (has links)
A significant problem with exploring for electrically conductive mineral deposits with airborne electromagnetic (AEM) methods is that many of the most valuable sulphide deposits are too conductive to be detected with conventional systems. High-grade sulphide deposits with bulk electrical conductivities on the order of 100,000 S/m can appear as “perfect conductors” to most EM systems because the decay of secondary fields (the “time constant” of the deposit) generated in the target by the system transmitter takes much longer than the short measuring time of EM systems. Their EM response is essentially undetectable with off-time measurements. One solution is to make measurements during the transmitter on-time when the secondary field of the target produced by magnetic flux exclusion is large. The difficulty is that the secondary field must be measured in the presence of a primary field which is orders of magnitude larger. The goal of this thesis is to advance the methodology of making AEM measurements during transmitter on-time by analysing experimental data from three different AEM systems. The first system analysed is a very large separation, two helicopter system where geometry is measured using GPS sensors. In order to calculate the primary field at the receiver with sufficient accuracy, the very large (nominally 400 m) separation requires geometry to be known to better than 1 m. Using the measured geometry to estimate and remove the primary field, I show that a very conductive target can be detected at depths of 200m using the total secondary field. I then used fluxgate magnetometers to correct for receiver rotation which allowed the component of the secondary field to be determined. The second system I examined was a large separation fixed-wing AEM system. Using a towed receiver bird with a smaller (˜ 135m) separation, the geometry must be known much more accurately. In the absence of direct measurement of this geometry, I used a least-squares prediction approach using measurements of aircraft manoeuvres which allowed primary field contamination to be estimated. Subtracting this estimate from the recorded signal increased the maximum time constant observed in a field survey for conductive targets by a factor of seven. Finally, a study of a nominally rigid helicopter EM system employing a bucking coil to cancel primary field showed that system geometry (specifically, the position of the receiver coil relative to the transmitter and bucking coils) must be known to better than 0.01 mm to detect deep targets. Again, direct measurements of system geometry were not available. A least-squares prediction filter using helicopter manoeuvre and system pitch and roll measurements was applied, but was not able to estimate primary field well enough to provide an accurate secondary on-time response. Direct measurements of relative motion of the system components might solve this problem.

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