Tesis sobre el tema "Mesure subjective"
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Benard, Yohann. "Mesure et prédiction de la vision subjective en présence d'aberrations monochromatiques". Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00663420.
Texto completoMalo, Roman. "Flexibilité psychologique, psychopathologie et réalité virtuelle : de la mesure subjective à la possibilité de mesure objective des processus transdiagnostiques". Electronic Thesis or Diss., Nantes Université, 2023. http://www.theses.fr/2023NANU2032.
Texto completoThis Ph.D, at the crossroads of clinical psychology, cognitive science and phenomenology, focuses on psychological flexibility. Its main aim is to clarify the notion of psychological flexibility and to measure it, based on an intégrative understanding and proposing a multi-level measurement and understanding, both in the associated theoretical perspectives (clinical, neuropsychological, phenomenological) and in the measurement tools used. After proposing a historical and epistemological review of the work on the évolution of the notion of psychological flexibility at the heart of a paradigmatic shift and the emergence of new perspectives such as transdiagnostic processual approaches and phenomenological approaches, we determined its main characteristics and proposed an initial online study aimed at enriching it. In a second and third study, we measured psychological flexibility in an everyday Virtual reality situation. By comparing two populations (study 2 - healthy population / study 3 - population with anxiety symptoms), we highlighted the value of a multimethod approach to détermine the characteristics of psychological flexibility. What emerges from these studies is the importance of understanding psychological flexibility as an organised, identifiable process in which the allocation of attentional resources and the identification of contextual eues play an important rôle in coping with an unexpected situation. These data are discussed with a view to extending research into psychological flexibility and its clinical and therapeutic applications
Voisin, Alexandre. "Contribution à l'évaluation subjective et son automatisation : du concept à l'application". Nancy 1, 1999. http://www.theses.fr/1999NAN10024.
Texto completoFigueiredo, Fábio Leão. "Indices acoustiques et leurs rapports statistiques : vérification objective et subjective pour un ensemble de salles de spectacles". Paris 6, 2011. http://www.theses.fr/2011PA066288.
Texto completoRegnault, Antoine. "Méthodes quantitatives pour l'évaluation de la validité interculturelle des instruments de mesure subjective évaluée par les patients". Lyon 1, 2007. http://www.theses.fr/2007LYO10086.
Texto completoMantel, Claire. "Bruits temporels de compression et perception de la qualité vidéo : mesure et correction". Phd thesis, Université de Grenoble, 2011. http://tel.archives-ouvertes.fr/tel-00680787.
Texto completoGuerra, Anne-Sophie. "Métrologie sensorielle dans le cadre du contrôle qualité visuel". Chambéry, 2008. http://www.theses.fr/2008CHAMS037.
Texto completoThe thesis deals with the problem of visual quality control of high quality manufactured products. We make the hypothesis that the control of this quality will be still realized many years by a visual inspection of the products. The first chapter presents a bibliographical study of different elements relating to the quality control in general, and particularly, the visual inspection. The chapter 2 describes the generic approach that we propose to perceive, then evaluate an anomaly. This approach separates in a formal way the perception of an anomaly from its evaluation. We show that this distinction gives a better comprehension of the variability sources in the visual inspection. Based on the approaches very largely used within the framework of the sensory analysis, our approach thus formalizes these two steps in order to reduce the variability in the decision of conformity during a visual inspection. The chapter 3 proposes a structuring metrological approach having for objective to guarantee the accuracy and the reduced variability in time and space. Our suggestion, based on the concepts of a dimensional metrology, integrates the specificities related to any sensory measurement carried out by the man, and in particular the part of significant subjectivity which can be associated to this measurement. Based on the evaluation of only one anomaly, we describe in the chapter 4 an approach allowing to decide acceptance or refusal of a product combining various anomalies on various surfaces. Our approach, based on the Taguchi's loss function, makes it possible to generalize with the visual inspection the approaches of tolerance largely used in geometrical quality of the products. The chapter 5 illustrates the application of these concepts within the company with which we collaborated. It also proposes a synthesis of profits that such an approach can produce
Baril, Mathieu. "Relation entre une mesure subjective des compétences émotionnelles de gestionnaires du domaine financier et leur niveau de performance au travail". Master's thesis, Université Laval, 2004. http://hdl.handle.net/20.500.11794/44608.
Texto completoHamad, Mohamad. "Validation psychométrique de mesures subjectives en santé orale". Electronic Thesis or Diss., Bourgogne Franche-Comté, 2024. http://www.theses.fr/2024UBFCE002.
Texto completoThe psychometric validation of a subjective measurement scale consists of many steps that we will expose and comment on during this thesis. We would rely more particularly on the work of psychometric validation of the Geriatric Oral Health Assessment Index (GOHAI) and the Schizophrenia Cooping Oral Health Profile and Index (SCOOHPI) that we have carried out. During the stages of the validation of this scale we particularly explored the question of the validity of the internal structure which is the heart of the reflexive field of our work. In this thesis we have 5 chapters. In Chapter 1, we defined the concepts to be studied and explained the relationship between schizophrenia and oral health, and presented the history of psychometric validation of subjective measurement scales.In chapter 2, we described the steps in the psychometric validation of subjective measurement scales, there are 2 main headings in psychometric validation: reliability and validity. Scale reliability is composed of 3 parts: internal consistency, reliability over time and sensitivity to change. The validity of the scale is composed of 4 parts: content validity, perceived validity, construct validity and structure validity.In chapter 3, we study the psychometric validation of the GOHAI (Geriatric Oral Health Assessment Index) scale in a sample of French patients with schizophrenia.Cronbach's alpha shows a significant degree of internal consistency between items and the test-retest verifies the reliability over time. Then, the construct validity shows the existence of a relationship between the GOHAI scale and the DMFT (Dent Cariée, Absente, Obturation) and OHI'S (Simplifed Oral Hygiene Index) indices. Afterwards, the principal component analysis shows the existence of 3 subscales: physical functions, psychosocial aspects and symptoms related to the presence of dental diseases. Finally, the partial credit model verifies that the GOHAI scale is not unidimensional.In Chapter 4, we study the structural validity of the GOHAI scale using a sample of the general French population.The principal component analysis shows the existence of 3 subscales: pain and appearance of the teeth, psychological satisfaction with the state of the teeth and ability to eat. Then, the partial credit model verifies the unidimensionality of the GOHAI scale after grouping the response modalities.In Chapter 5, we study the psychometric validation of the Schizophrenia Coping Oral Health Profile and Index (SCOOHPI) scale using a sample of French patients with schizophrenia.The panel confirmed the content validity of the SCOOHPI scale. Perceived validity was verified with 30 individuals. Then, Cronbach's alpha shows a good degree of internal consistency between items. Then, the absence of relationship between the SCOOHPI scale and the GOHAI scale confirms the validity of the divergence. While the validity of the convergence was not measurable due to the lack of tools that measure a similar concept to the SCOOHPI scale concept.The principal component analysis shows the existence of 6 subscales: oral health, diet and oral hygiene, activity and organization, addiction and avoidance strategies. Finally, the partial credit model shows that the SCOOHPI scale is unidimensional after grouping the response modalities
Ramón-Moliner, Carmen Elisabeth. "Qualité de vie subjective des personnes ayant participé à un programme de réadaptation au travail en raison de troubles musculo-squelettiques comparaison selon la situation de travail". Mémoire, Université de Sherbrooke, 2007. http://savoirs.usherbrooke.ca/handle/11143/3888.
Texto completoMuñoz, Arancón Alberto. "New techniques for the characterisation of single reeds in playing conditions". Thesis, Le Mans, 2017. http://www.theses.fr/2017LEMA1031/document.
Texto completoThis work deals with the characterisation of single cane reeds used for clarinet or saxophone. Musicians perceive important differences of quality between reeds of the same brand, cut and strength. This thesis proposes new tools for reed characterisation in playing conditions.An instrumented mouthpiece is developed to enable the measurement of reed displacement and pressure difference on both sides of the reed using embedded sensors. From these signals, it is possible to estimate reed parameters of different physical models. Results reveal that the complexity of the physical model describing the reed behaviour must increase with the dynamic level.The instrumented mouthpiece is used in a measurement campaign involving 7 players and 20 reeds, quantifying the variability of the results due the musicians. Subjective tests conducted with these musicians show that reeds can be mainly described by one dimension (ease of playing or timbre). The correlations between the subjective descriptors and the measured objective parameters are studied to better understand the perceived differences between reeds, developing a predictive model of reed quality.In order to avoid the variability of the musician, an aspirating artificial mouth is developed. It uses the instrumented mouthpiece and it can be played by a musician or artificially. The comparison of the measurements made in both cases allows for the identification of the optimal working range in which the artificial mouth best reproduces the musician's playing according to intonation and playing level
Kop, Jean-Luc. "Le bien-être subjectif vers une mesure du bonheur". Nancy 2, 1994. http://docnum.univ-lorraine.fr/public/NANCY2/doc391/1994NAN21024_1.pdf.
Texto completoRouquette, Alexandra. "Mesures subjectives et épidémiologie : problèmes méthodologiques liés à l’utilisation des techniques psychométriques". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA11T097/document.
Texto completoRecently, subjective measurements have increasingly been used in epidemiology, alongside the growing will to integrate individuals’ point of view on their health in studies on diseases or health interventions. Psychometrics includes statistical methods used to develop questionnaires and to analyze questionnaire data. This doctoral dissertation aimed to explore methodological issues raised by the use of psychometric techniques in epidemiology. Three empirical studies are presented and cover 1 / the validation stage of a questionnaire: the objective was to develop, using simulated data, a tool to determine sample size for internal validity studies on psychiatric scale; 2 / the mathematical properties of the subjective measurement: the objective was to compare the performances of the minimal clinically important difference of a questionnaire, assessed on data from a cohort study, computed using the classical test theory (CTT) framework or the item response theory framework (IRT); 3 / its use in a longitudinal design: the objective was to compare, using simulated data, the performances of a statistical method aimed to analyze the longitudinal course of a subjective phenomenon measured using the CTT or IRT framework, especially when some of the available items used for its measurement differ at each time of data collection. Finally, directed acyclic graphs were used to discuss the results from these three studies and the concept of information bias when subjective measurements are used in epidemiology
Ismael, Afraa. "Le problème du temps chez Saint Augustin et Saint Thomas d’Aquin". Thesis, Bordeaux 3, 2013. http://www.theses.fr/2013BOR30046.
Texto completoThis thesis has for aim to explore the problematic of the time within the reflections of St Augustine and St Thomas Aquinas that are both seen as a key link between the philosophical thought of the antiquity and the contemporary period. It will firstly analyze the theories developed by these two philosophers on the concept and the measure of the time, to give an answer to the question: has the time a reality and how to measure it?Through a deep analyze of the two philosophers’ corpus referentials, this study will try to determine if it is possible to find the answer in the changing, the motion, the succession, the duration, the moment and the present or if we rather have to see the time as a shape of the objective world or as a scheme of the apprehension depending on the subject. The first part of this work will answer the question whether the time reflects the properties of the objective world itself or those of the subjective world or might it be the result of the links we have with these two worlds. The second will analyze the problematic of the time between its origin and its end (the creation and the eternity). We will try to know if it is possible to show that the philosophical analysis of the time made by these two authors cannot be seen as an independent instant but a way to reconsider the subject of the time in a theology of creation and eternity.In a broad analysis of the four themes that are, the reality, the measure of the time, the creation and the eternity and some specifics and close concepts, we will determine if it is possible to say that there is an absolute gap between the time as a cosmic category and the time as a psychological one. We will show precisely if it is possible to say that the St Augustine and St Thomas Aquinas’s thoughts can be looked as two different theories, the one which sees the time as a subjective reality and allows St Augustine to be considered one of the most significant founders of the phenomenology of the time unlike St Thomas Aquinas who demonstrates the time's objective reality, in the continuity of the Aristotelian objectivity of the time
Quintard, Ludovic. "Evaluation de la qualité des dispositifs d'affichage couleur : des évaluations subjectives à la mesure objective". Poitiers, 2008. http://theses.edel.univ-poitiers.fr/theses/2008/Quintard-Ludovic/2008-Quintard-Ludovic-These.pdf.
Texto completoThis thesis was conducted in cooperation with the Laboratoire National de Métrologie et d’Essais (LNE) within the framework of a CIFRE convention. This work consisted in realising an objective metric dedicated to the assessment of image retrieval devices (screens). To address the underlying issues, we developed an algorithm for estimating quality using the monitor features and those of the Human Visual System. The developed algorithm is made up of three blocks. The first block takes into account the technical features of the monitor (transfer function, gamut, etc. ) to turn a digital image (sent to the monitor using a digital device) into a physical image (displayed by the monitor). The second block of the algorithm models the transformation of the physical image into a perceptual image. This modelling involves familiarity with human visual system operational principles, particularly the encoding of colour information, as well as the perceptual attributes involved in judging a colour digital image quality. The required knowledge is described in chapter 4 of the present thesis. The third and last block was developed to rate the quality of this perceptual image. A subjective study of the quality of 5 different LCD screens involving thirty participants and based on six analysis criteria was performed. It successfully showed that colour, saturation and contrast are major factors on which the screen quality is assessed. The metric developed was based on these findings and shows good correlation with subjective evaluation data, thus showing similarity with human judgement. The metric was also tested in the field of JPEG and JPEG2000 compression with similar efficiency
Quintard, Ludovic Fernandez-Maloigne Christine Larabi Mohamed-Chaker. "Evaluation de la qualité des dispositifs d'affichage couleur des évaluations subjectives à la mesure objective /". Poitiers : I-Médias, 2008. http://08.edel.univ-poitiers.fr/theses/index.php?id=1719.
Texto completoSaidi, Inès. "Analyse et modélisation de la qualité perçue des applications de visiophonie". Thesis, Rennes, INSA, 2018. http://www.theses.fr/2018ISAR0013/document.
Texto completoIn a highly competitive environment, one of the key challenges for operators and providers of video telephony services is to ensure the highest quality of experience (QoE). There is a strong need for a measure that reflects users satisfaction and perception of these services. The audio-visual quality of a video call must be controlled to meet two main needs. The first concerns the planning of new technologies under development. The second is focused on the control of existing communications by assessing the quality of the services offered and evaluating them. Two approaches are used to evaluate audio-visual quality: subjective tests by collecting scores given by participants on quality scales, after viewing and listening to audiovisual sequences and objective metrics based on automatic audio/ video or audiovisual quality evaluation algorithms. Concerning telephony services, decades of research, standardization work and network exploitation, have allowed operators to master the automatic monitoring tools and to determine the representative metrics of voice quality. However, the metrics for measuring the audiovisual quality of a conversational services are not yet mature and not exploited by telecommunication operators. The present work focuses on finding representative metrics of the perception of the video telephony anc videoconferencing services quality. These objective metrics are calculated from the audio and video signals. Subjective tests are conducted to collect the judgment of service users on the perceived quality according to different levels of degradation. We studied the impact of network conditions (packet loss, jitter and desynchronization) on the QoE of a video call. The general principle is then to establish a correlation between the selected objective metrics and the perceived quality as expressed by the users. The results showed that new metric of overall audiovisual quality that take into account the temporal aspect of video are more powerful than image quality based metrics. On the other hand, the use of a machine learning approach represents a solution to generat a global quality prediction model from the degradation metrics (blur, pixelization, image freezing, ... )
Resseguier, Noémie. "Méthodes de gestion des données manquantes en épidémiologie. : Application en cancérologie". Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM5063.
Texto completoThe issue of how to deal with missing data in epidemiological studies is a topic which concerns every researcher involved in the analysis of collected data and in the interpretation of the results produced by these analyses. And even if the issue of the handling of missing data and of their impact on the validity of the results is often discussed, simple, but not always appropriate methods to deal with missing data are commonly used. The use of each of these methods is based on some hypotheses under which the obtained results are valid, but it is not always possible to test these hypotheses. The objective of this work was (i) to propose a review of various methods to handle missing data used in the field of epidemiology, and to discuss the advantages and disadvantages of each of these methods, (ii) to propose a strategy of analysis in order to study the robustness of the results obtained via classical methods to handle missing data to the departure from hypotheses which are required for the validity of these results, although they are not testable, and (iii) to propose some applications on real data of the issues discussed in the first two sections
Henschel, Sébastien. "Rôle de l'attachement sur les processus de régulation émotionnelle et d'empathie : mesures subjectives et neurovégétatives". Thesis, Lille 3, 2020. http://www.theses.fr/2020LIL3H025.
Texto completoThe aim of this thesis work is to identify the existing relationships between different attachment styles and the development of socio-emotional competences such as emotion regulation and empathy in adulthood. According to a multidimensional perspective, emotional regulation, affective empathy, cognitive empathy and prosocial behaviours can be regarded as interacting components with different developmental trajectories and disturbances depending on the individual's relational history. The influence of attachment experiences on the development of empathic capacities can thus be characterized at different levels ranging from cognitive and emotional processes to physiological responses. The aim of the first study was to evaluate the influence of attachment styles on self-reported emotional regulation capacities and difficulties and cognitive and affective dimensions of empathy in adults. Results showed higher scores of personal distress and fantasy in insecure-anxious individuals than in secure and insecure-avoidant individuals. The results also revealed that individuals with anxious attachment reported more emotion regulation difficulties than insecure-avoidant individuals. In addition, PLS-PM modeling analyses showed that the mediating role of emotion regulation in the relationship between attachment and empathy varied according to attachment styles and dimensions of empathy. The aim of the second study was to examine the effects of attachment styles (secure, insecure-anxious, and insecure-avoidant) on physiological activation (i.e. electrodermal activity) during a cognitive empathy task (i.e. self and other perspective-taking) in response to socio-emotional attachment situations (situations of distress, comfort, and neutral interactions ; BAPS ; Szymanska et al., 2015). Regarding distress situations, results showed that insecure-anxious individuals had higher physiological responses than secure individuals when adopting a self-perspective. Regarding comfort situations, insecure-anxious individuals presented higher physiological responses than secure individuals in the other perspective-taking condition. Correlational analyses also revealed an important negative association between perspective-taking scores and physiological responses in secure individuals. Taken together, both studies suggest that the perception of attachment experiences is associated with different socio-emotional competences such as empathy and emotion regulation. These differences are associated with specific physiological responses to socio-emotional attachment situations. Thus, the analysis of attachment experiences is a major line of work, both for the development of scientific research protocols and for therapeutic applications. A range of research perspectives and clinical and therapeutic applications are opening up and will therefore be discussed in light of these conclusions
Hamel-Broza, Jean-François. "Étude de différentes méthodologies de comparaison de groupes d'individus par l'analyse de mesures subjectives en santé". Nantes, 2014. http://archive.bu.univ-nantes.fr/pollux/show.action?id=4a0679ed-2c26-46da-8daa-bc8dfd6c3813.
Texto completoIn clinical research, a comprehensive understanding of the concept of health is possible by performing subjective measurements carried out using standardized self-assessment questionnaires. Different strategies can be considered allowing comparing groups of individuals by analysing such questionnaires in a cross-sectional framework. The respective properties of such methods - based on the classical test theory or the item response theory - were studied and compared depending on their usage circumstances. When there is no missing data, i. E. The questionnaires have no missing response, simply comparing the individuals scores using a t-test allows a powerful and unbiased comparison of the individuals groups. On the contrary and when some data is missing, i. E. People have not responded to all of the proposed items, no simple method allows an unbiased comparison of individuals groups. In this case, only two methods allow such a powerful and unbiased comparison. The first is based on a multiple imputation process, modelling items responses by a linear mixed model. The second is based on testing the significance of a covariate included in a random effects Rach family model. No imputation process is required with this latter. Software are proposed for assisting the implementation of the last two methods: additional Stata® modules and online statistical tools
Vuillet, Marc. "Élaboration d’un modèle d’aide à la décision probabiliste pour l’évaluation de la performance des digues fluviales". Thesis, Paris Est, 2012. http://www.theses.fr/2012PEST1186.
Texto completoLevee risk control is crucial, as flood defense failures may seriously affect human life or economics issues. The regulation in France relating to the safety of the hydraulic structures is recently evolved (decree of December 11, 2007) and henceforth envisages for levees the realization of regular diagnoses and studies of dangers and encourages a probabilistic evaluation of levees safety. A levee safety evaluation currently consists in appraising the work, including taking into account data stemming from various prior investigations: historical records, visual inspections, hydraulic modeling, geophysical explorations, geotechnical explorations, etc. Such investigations may be performed to a more or less comprehensive extent, according to the resources available. Levee diagnostic studies will first split the alignments into several homogenous construction and loading sections, then complete an expert quality assessment of their performance levels. The goal of our research is to develop a probabilistic model for performance assessment of river levees, for a quick or comprehensive diagnosis. The model give support for engineer and make possible to determine how much an evaluation may be trusted and will help decide which levee sections should be primarily subjected to action or investigations. This will also facilitate the decision making process regarding technical actions to be taken to improve a levee section performance. Our approach contains three main steps:- analyzing and modeling levees failure mechanisms with a functional model build up from risk analysis methods ;- construction of deterministic decision aid model including levees performance indicator, using unicriterion decision support methods ;- construction of a probabilistic-based model for evaluating levees performance. Such model taking into account the input data uncertainty by using subjective probabilities. Our research results are illustrated by model application on cases studies
Trépanier, Sylvie. "Étude des liens entre l'évaluation subjective et objective de la mémoire et des mesures psychosociales chez des personnes âgées entre 55 et 65 ans". Thèse, Université du Québec à Trois-Rivières, 1994. http://depot-e.uqtr.ca/5307/1/000611298.pdf.
Texto completoPeiffert, Olivier. "L’application du droit européen des aides d’État aux mesures de protection de l’environnement". Thesis, Université de Lorraine, 2013. http://www.theses.fr/2013LORR0350/document.
Texto completoEnvironmental protection policies for European Union members usually create a need for public subsidies. They therefore fall within the scope of the rules of the founding treaties of the EU which prohibits state aid and organizes their control. In applying these rules an independent legal framework arises that subject the policies of the environmental protection to the open and free competition.The scope of this legal framework depends on the qualification of the measures of environmental protection with regards to the legal concept of state aid. This qualification is based on objective criteria, which, though not perfect, concludes that only market-based instruments for environmental protection are relevant for the control of the subsidies. The precise determination of the scope of the category of aid is, however, superseeded by the regular intervention of subjective factors allowing the institutions to choose when it comes to qualification.The impact of the legal framework needs to be considered against the environmental legislation of the EU. In theory this later could lead to harmonisation of competition in the internal market. In practice, however, its content triggers the law of state aid leading to a complex and sometimes conflicting relationship between those two sets of rules, while the discretionary exercise of the EU Commission’s power for the definition of the legal regime leads to a quasi-harmonisation of the environmental sector
Assila, Ahlem. "Une approche et un outil pour l'évaluation subjective et objective de l'utilisabilité des systèmes interactifs : application à un système d'aide à l'information voyageurs". Thesis, Valenciennes, 2016. http://www.theses.fr/2016VALE0026/document.
Texto completoUsability evaluation for interactive systems is one of the greatest interests for Human-Computer Interaction community. To the success of this evaluation, several subjective and objective evaluation methods and tools have been proposed and applied in academy and industry. In this context, usability evaluators usually work with a lot of and different kind of data. These data are generated from various methods and tools and related to different usability criteria. In general, understanding and interpreting these heterogeneous data are not easy tasks. In this thesis, we propose to integrate subjective and objective evaluation data to better support the quality evaluators’ decision-making for traffic supervision systems domain. In fact, we applied the measurement information model defined by ISO/IEC 15939 with the use of indicators in an interactive system evaluation environment. The development of this environment has started in a decade. Thus, for completing implementation and putting it into practice, we have applied several proposed usability indicators in the evaluation of a traffic supervision system. These indicators integrate subjective and objective evaluation results from usability questionnaires, an ergonomic guidelines inspector and an electronic informer. They provide a basis for aiding the interpretation of their results obtained. Furthermore, they allow detecting usability problems and give recommendations for enhancing the user interfaces. Finally, this thesis propose research perspectives based on the encountered limits
Rekik, Siwar. "Sécurisation de la communication parlée par une techhnique stéganographique". Thesis, Brest, 2012. http://www.theses.fr/2012BRES0061.
Texto completoOne of the concerns in the field of secure communication is the concept of information security. Today’s reality is still showing that communication between two parties over long distances has always been subject to interception. Providing secure communication has driven researchers to develop several cryptography schemes. Cryptography methods achieve security in order to make the information unintelligible to guarantee exclusive access for authenticated recipients. Cryptography consists of making the signal look garbled to unauthorized people. Thus, cryptography indicates the existence of a cryptographic communication in progress, which makes eavesdroppers suspect the existence of valuable data. They are thus incited to intercept the transmitted message and to attempt to decipher the secret information. This may be seen as weakness in cryptography schemes. In contrast to cryptography, steganography allows secret communication by camouflaging the secret signal in another signal (named the cover signal), to avoid suspicion. This quality motivated the researchers to work on this burning field to develop schemes ensuring better resistance to hostile attackers. The word steganography is derived from two Greek words: Stego (means cover) and graphy (means writing). The two combined words constitute steganography, which means covert writing, is the art of hiding written communications. Several steganography techniques were used to send message secretly during wars through the territories of enemies. The major contributions of this thesis are the following ones. We propose a new method to secure speech communication using the Discrete Wavelet Transforms (DWT) and the Fast Fourier Transform (FFT). Our method exploits first the high frequencies using a DWT, then exploits the low-pass spectral properties of the speech magnitude spectrum to hide another speech signal in the low-amplitude high-frequencies region of the cover speech signal. The proposed method allows hiding a large amount of secret information while rendering the steganalysis more complex. Comparative evaluation based on objective and subjective criteria is introduced for original speech signal, stego-signal and reconstructed secret speech signal after the hiding process. Experimental simulations on both female and male speakers revealed that our approach is capable of producing a stego speech that is indistinguishable from the cover speech. The receiver is still able to recover an intelligible copy of the secret speech message. We used an LPC10 coder to test the effect of the coding techniques on the stego-speech signals. Experimental results prove the efficiency of the used coding technique since intelligibility of the stego-speech is maintained after the encoding and decoding processes. We also advocate a new steganalysis technique to ensure the robustness of our steganography method. The proposed classifier is called Autoregressive time delay neural network (ARTDNN). The purpose of this steganalysis system is to identify the presence or not of embedded information, and does not actually attempt to extract or decode the hidden data. The low detecting rate prove the robustness of our hiding technique
Baudot, Matthias. "Investigation des corrélations existant entre la perception de qualité audio et les réactions physiologiques d'un auditeur". Mémoire, Université de Sherbrooke, 2010. http://savoirs.usherbrooke.ca/handle/11143/1560.
Texto completoBrunault, Paul. "Etude des facteurs psychopathologiques associés à la dépression, à la qualité de vie et à l'adiction [sic] à l'alimentation dans le cadre de la maladie chronique à partir du modèle de Wilson et Cleary". Thesis, Tours, 2015. http://www.theses.fr/2015TOUR2020/document.
Texto completoThis article thesis aimed to assess risk factors for three different health outcome measures (depression, health-related quality of life and food addiction) in two populations (breast cancer patients and morbidly obese patients), by assessing the relative impact of biological and physiological variables (i.e., disease duration and severity, types of treatment used), and individual and psychological variables (i.e., psychiatric disorders, personality). By proposing and putting to the test several integrative biopsychosocial models based on Wilson and Cleary’s theoretical model, we demonstrated that : 1) Depression after breast cancer treatment is more strongly associated with variables related to the premorbid individual and psychological characteristics (i.e., personality and depression before treatment) than to biological and physiological variables (i.e., disease severity, types of treatment used) ; 2) Risk factors for lower quality of life are different depending on the quality of life dimension considered (e.g., physical, psychological or sexual) : biological and physiological variables are associated with physical quality of life ; individual and psychological factors are associated with all quality of life dimensions ; 3) Obese patients with food addiction exhibit some specific psychopathological risk factors. Our work suggest to systematically assess individual and psychological variables in patients with chronic diseases because these variables are important potential predictors for different health outcomes
Baril, Mathieu. "Relation entre une mesure subjective des compétences émotionnelles de gestionnaires du domaine financier et leur niveau de performance au travail /". 2004. http://proquest.umi.com/pqdweb?did=790298561&sid=5&Fmt=2&clientId=9268&RQT=309&VName=PQD.
Texto completoZidarov, Diana. "Évolution de la qualité de vie des personnes amputées d'un membre inférieur suite à une réadaptation fonctionnelle". Thèse, 2008. http://hdl.handle.net/1866/7600.
Texto completoRouquette, Alexandra. "Mesures subjectives et épidémiologie : problèmes méthodologiques liés à l'utilisation des techniques psychométriques". Thèse, 2014. http://hdl.handle.net/1866/12091.
Texto completoRecently, subjective measurements have increasingly been used in epidemiology, alongside the growing will to integrate individuals’ point of view on their health in studies on diseases or health interventions. Psychometrics includes statistical methods used to develop questionnaires and to analyze questionnaire data. This doctoral dissertation aimed to explore methodological issues raised by the use of psychometric techniques in epidemiology. Three empirical studies are presented and cover 1 / the validation stage of a questionnaire: the objective was to develop, using simulated data, a tool to determine sample size for internal validity studies on psychiatric scale; 2 / the mathematical properties of the subjective measurement: the objective was to compare the performances of the minimal clinically important difference of a questionnaire, assessed on data from a cohort study, computed using the classical test theory (CTT) framework or the item response theory framework (IRT); 3 / its use in a longitudinal design: the objective was to compare, using simulated data, the performances of a statistical method aimed to analyze the longitudinal course of a subjective phenomenon measured using the CTT or IRT framework, especially when some of the available items used for its measurement differ at each time of data collection. Finally, directed acyclic graphs were used to discuss the results from these three studies and the concept of information bias when subjective measurements are used in epidemiology.
LASSALLE, Julie. "Etude de l'influence de la qualité audiovisuelle sur la qualité d'expérience du spectateur : combinaison d'indicateurs subjectifs, physiologiques et oculaires". Phd thesis, 2013. http://tel.archives-ouvertes.fr/tel-00960921.
Texto completoCrété-Roffet, Frédérique. "Estimer, mesurer et corriger les artefacts de compression pour la télévision numérique". Phd thesis, 2007. http://tel.archives-ouvertes.fr/tel-00229416.
Texto completoEn estimant quels sont les artefacts les plus gênants et les risques encourus à les corriger, nous définissons la problématique de ce travail : comment corriger les effets de bloc et de ringing qui sont des artefacts de compression sans risquer de faire apparaître un artefact de correction tel que le flou ?
Les métriques objectives, validées par des tests subjectifs, permettent de mesurer ces artefacts. L'étude de l'état de l'art, associée à la modélisation de notre manière de percevoir ces artefacts, nous permet d'aboutir au développement du BLE (Block Level Estimator) et du BluM (Blur Metric), métriques objectives destinées à estimer respectivement leffet de bloc et le flou sur une image.
La correction de l'effet de bloc et de l'effet de ringing peut ensuite être guidée et validée par ces métriques. Nous proposons des modules permettant d'améliorer, de rendre plus robustes et d'implémenter facilement les corrections existantes. Puis, pour résoudre la problématique, nous intégrons ces modules dans une solution générale appelée SQDSE (Studio Quality Digital Source Enhancement) destinée à supprimer les effets de bloc et de ringing. La structure du SQDSE et sa validation par des tests visuels et par les résultats du BLE et du BluM montrent que le compromis entre l'efficacité, la robustesse et la simplicité est atteint.
Leclaire, Sarah. "Sommes-nous de bons juges de notre stress? Marqueurs subjectifs et physiologiques de stress chez de jeunes adultes se disant ‘zen’ versus très stressés". Thèse, 2018. http://hdl.handle.net/1866/22146.
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