Dissertations / Theses: 'Objective and subjective quality'

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Torkhani, Fakhri. "Analyse subjective et évaluation objective de la qualité perceptuelle des maillages 3D." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENT051/document.

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Les maillages 3D polygonaux sont largement utilisés dans diverses applications telles que le divertissement numérique, la conception assistée par ordinateur et l'imagerie médicale. Un maillage peut être soumis à différents types d'opérations comme la compression, le tatouage ou la simplification qui introduisent des distorsions géométriques (modifications) à la version originale. Il est important de quantifier ces modification introduites au maillage d'origine et d'évaluer la qualité perceptuelle des maillages dégradés. Dans ce cadre, on s'intéresse dans cette thèse à l'évaluation de la qualité perceptuelle des maillages 3D statiques et dynamiques. On présente des études expérimentales pour l'évaluation subjective de la qualité des maillages 3D dynamiques.On présente également de nouvelles métriques objectives, de type avec-référence complète ou de type avec référence-réduite, qui sont efficaces pour l'estimation de la qualité perçue des maillages statiques et dynamiques 3D mesh animations have been increasingly used in various applications, e.g., in digital entertainment, computer-aided design and medical imaging. It is possible that a mesh model undergoes some lossy operations, e.g., compression, watermarking or simplification, which can impair the original mesh surface and introduce geometric distortions. An important task is to quantify such distortions and assess the perceptual quality of impaired meshes. In this manuscript, we focus on the perceptual quality assessment of 3D static and dynamic meshes. We present psychometric experiments that we conducted to measure the subjective perceptual quality of dynamic meshes. We also present new full-reference and reduced-reference objective metrics capable of faithfully evaluating the perceptual quality of 3D static and dynamic meshes

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Sendjasni, Abderrezzaq. "Objective and subjective quality assessment of 360-degree images." Electronic Thesis or Diss., Poitiers, 2023. http://www.theses.fr/2023POIT2251.

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Les images à 360 degrés, aussi appelées images omnidirectionnelles, sont au cœur des contenus immersifs. Avec l’augmentation de leur utilisation notamment grâce à l’expérience interactive et immersive qu’ils offrent, il est primordial de garantir une bonne qualité d’expérience (QoE). Cette dernière est considérablement impactée par la qualité du contenu lui-même. En l’occurrence, les images à 360 degrés, comme tout type de signal visuel, passent par une séquence de processus comprenant l’encodage, la transmission, le décodage et le rendu. Chacun de ces processus est susceptible d’introduire des distorsions dans le contenu. Pour améliorer la qualité d’expérience, toutes ces dégradations potentielles doivent être soigneusement prises en compte et réduites à un niveau imperceptible. Pour atteindre cet objectif, l’évaluation de la qualité de l’image est l’une des stratégies devant être utilisée. Cette thèse aborde l’évaluation de la qualité des images à 360 degrés des points de vue objectif et subjectif. Ainsi, en s’intéressant à l’effet des visiocasques sur la qualité perçue des images 360 degrés, une étude psycho-visuelle est conçue et réalisée en utilisant quatre dispositifs différents. À cette fin, une base de données a été créé et un panel d’observateurs a été impliqué. L’impact des visiocasques sur la qualité a été identifié et mis en évidence comme un facteur important à prendre en compte lors de la réalisation d’expériences subjectives pour des images à 360 degrés. D’un point de vue objectif, nous avons d’abord procédé à une étude comparative extensive de plusieurs modèles de réseaux de neurones convolutifs (CNN) sous diverses configurations. Ensuite, nous avons amélioré la chaîne de traitement de l’évaluation de la qualité basée sur les CNN à différentes échelles, de l’échantillonnage et de la représentation des entrées à l’agrégation des scores de qualité. En se basant sur les résultats de ces études, et de l’analyse comparative, deux modèles de qualité basés sur les CNN sont proposés pour prédire avec précision la qualité des images à 360 degrés. Les observations et les conclusions obtenues à partir des différentes contributions de cette thèse apporteront un éclairage sur l’évaluation de la qualité des images à 360 degrés 360-degree images, a.k.a. omnidirectional images, are in the center of immersive media. With the increase in demands of the latter, mainly thanks to the offered interactive and immersive experience, it is paramount to provide good quality of experience (QoE). This QoE is significantly impacted by the quality of the content. Like any type of visual signal, 360-degree images go through a sequence of processes including encoding, transmission, decoding, and rendering. Each of these processes has the potential to introduce distortions to the content. To improve the QoE, image quality assessment (IQA) is one of the strategies to be followed. This thesis addresses the quality evaluation of 360-degree images from the objective and subjective perspectives. By focusing on the influence of Head Mounted Displays (HMDs) on the perceived quality of 360-degree images, a psycho-visual study is designed and carried out using four different devices. For this purpose, a 360-degree image datasets is created and a panel of observers is involved. The impact of HMDs on the quality ratings is identified and highlighted as an important factor to consider when con- ducting subjective experiments for 360-degree images. From the objective perspective, we first comprehensively benchmarked several convolutional neural network (CNN) models under various configurations. Then, the processing chain of CNN-based 360-IQA is improved at different scales, from input sampling and representation to aggregating quality scores. Based on the observations of the above studies as well as the benchmark, two 360-IQA models based on CNNs are proposed to accurately predict the quality of 360-degree images. The obtained observations and conclusions from the various contributions shall bring insights for assessing the quality of 360-degree images 360-graders bilder, også kjent som rundstrålende bilder, er i sentrum av oppslukende medier. Med økningen i forventninger til sistnevnte, hovedsakelig takket være den aktiverte interaktive og oppslukende opplevelse, er det avgjørende å gi god kvaliteten på opplevelsen (QoE).Denne QoE er betydelig påvirket av kvaliteten på innholdet. Som alle typer visuelle signaler går 360-graders bilder gjennom en sekvens av prosesser, inkludert koding, overføring, dekoding og gjengivelse. Hver av disse prosessene har potensial til å introdusere forvrengninger til innholdet.For å forbedre QoE er vurdering av bildekvalitet (IQA) en av strategiene å følge. Denne oppgaven tar for seg kvalitetsevaluering av 360-graders bilder fra objektive og subjektive perspektiver. Ved å fokusere på påvirkningen av Head Mounted Displays (HMD-er) på den oppfattede kvaliteten til 360-graders bilder, er en psyko-visuell studie designet og utført ved hjelp av fire forskjellige enheter. For dette formålet opprettes et 360-graders bildedatasett og et panel av observatører er involvert. Virkningen av HMD-er på valitetsvurderingene identifiseres og fremheves som en viktig faktor når du utfører subjektive eksperimenter for 360-graders bilder.Fra det objektive perspektivet benchmarket vi først flere konvolusjonelle nevrale nettverk (CNN) under forskjellige konfigurasjoner. Deretter forbedres prosesseringskjeden til CNN-baserte 360-IQA i forskjellige skalaer, fra input-sampling og representasjon til aggregering av kvalitetspoeng. Basert på observasjonene av de ovenfornevnte studiene så vel som benchmark, foreslås to 360-IQA-modeller basert på CNN-er for å nøyaktig forutsi kvaliteten på 360-graders bilder.De innhentede observasjonene og konklusjonene fra de ulike bidragene skal gi innsikt for å vurdere kvaliteten på 360-graders bilder

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Malekmohamadi, Hossein. "Objective models for subjective quality estimate of stereoscopic video." Thesis, University of Surrey, 2013. http://eprints.lincoln.ac.uk/12756/.

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Sadeghi, Reza. "Predicting Subjective Sleep Quality Using Objective Measurements in Older Adults." Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1588627876830938.

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Dalasari, Venkata Gopi Krishna, and Sri Krishna Jayanty. "Low Light Video Enhancement along with Objective and Subjective Quality Assessment." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13500.

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Enhancing low light videos has been quite a challenge over the years. A video taken in low light always has the issues of low dynamic range and high noise. This master thesis presents contribution within the field of low light video enhancement. Three models are proposed with different tone mapping algorithms for extremely low light low quality video enhancement. For temporal noise removal, a motion compensated kalman structure is presented. Dynamic range of the low light video is stretched using three different methods. In Model 1, dynamic range is increased by adjustment of RGB histograms using gamma correction with a modified version of adaptive clipping thresholds. In Model 2, a shape preserving dynamic range stretch of the RGB histogram is applied using SMQT. In Model 3, contrast enhancement is done using CLAHE. In the final stage, the residual noise is removed using an efficient NLM. The performance of the models are compared on various Objective VQA metrics like NIQE, GCF and SSIM. To evaluate the actual performance of the models subjective tests are conducted, due to the large number of applications that target humans as the end user of the video.The performance of the three models are compared for a total of ten real time input videos taken in extremely low light environment. A total of 25 human observers subjectively evaluated the performance of the three models based on the parameters: contrast, visibility, visually pleasing, amount of noise and overall quality. A detailed statistical evaluation of the relative performance of the three models is also provided.

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Guo, Jinjiang. "Contributions to objective and subjective visual quality assessment of 3d models." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI099.

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Dans le domaine de l’informatique graphique, les données tridimensionnelles, généralement représentées par des maillages triangulaires, sont employées dans une grande variété d’applications (par exemple, le lissage, la compression, le remaillage, la simplification, le rendu, etc.). Cependant, ces procédés introduisent inévitablement des artefacts qui altèrent la qualité visuelle des données 3D rendues. Ainsi, afin de guider perceptuellement les algorithmes de traitement, il y a un besoin croissant d'évaluations subjectives et objectives de la qualité visuelle à la fois performantes et adaptées, pour évaluer et prédire les artefacts visuels. Dans cette thèse, nous présentons d'abord une étude exhaustive sur les différentes sources d'artefacts associés aux données numériques graphiques, ainsi que l’évaluation objective et subjective de la qualité visuelle des artefacts. Ensuite, nous introduisons une nouvelle étude sur la qualité subjective conçue sur la base de l’évaluations de la visibilité locale des artefacts géométriques, dans laquelle il a été demandé à des observateurs de marquer les zones de maillages 3D qui contiennent des distorsions visibles. Les cartes de distorsion visuelle collectées sont utilisées pour illustrer plusieurs fonctionnalités perceptuelles du système visuel humain (HVS), et servent de vérité-terrain pour évaluer les performances des attributs et des mesures géométriques bien connus pour prédire la visibilité locale des distorsions. Notre deuxième étude vise à évaluer la qualité visuelle de modèles 3D texturés, subjectivement et objectivement. Pour atteindre ces objectifs, nous avons introduit 136 modèles traités avec à la fois des distorsions géométriques et de texture, mené une expérience subjective de comparaison par paires, et invité 101 sujets pour évaluer les qualités visuelles des modèles à travers deux protocoles de rendu. Motivés par les opinions subjectives collectées, nous proposons deux mesures de qualité visuelle objective pour les maillages texturés, en se fondant sur les combinaisons optimales des mesures de qualité issues de la géométrie et de la texture. Ces mesures de perception proposées surpassent leurs homologues en termes de corrélation avec le jugement humain In computer graphics realm, three-dimensional graphical data, generally represented by triangular meshes, have become commonplace, and are deployed in a variety of application processes (e.g., smoothing, compression, remeshing, simplification, rendering, etc.). However, these processes inevitably introduce artifacts, altering the visual quality of the rendered 3D data. Thus, in order to perceptually drive the processing algorithms, there is an increasing need for efficient and effective subjective and objective visual quality assessments to evaluate and predict the visual artifacts. In this thesis, we first present a comprehensive survey on different sources of artifacts in digital graphics, and current objective and subjective visual quality assessments of the artifacts. Then, we introduce a newly designed subjective quality study based on evaluations of the local visibility of geometric artifacts, in which observers were asked to mark areas of 3D meshes that contain noticeable distortions. The collected perceived distortion maps are used to illustrate several perceptual functionalities of the human visual system (HVS), and serve as ground-truth to evaluate the performances of well-known geometric attributes and metrics for predicting the local visibility of distortions. Our second study aims to evaluate the visual quality of texture mapped 3D model subjectively and objectively. To achieve these goals, we introduced 136 processed models with both geometric and texture distortions, conducted a paired-comparison subjective experiment, and invited 101 subjects to evaluate the visual qualities of the models under two rendering protocols. Driven by the collected subjective opinions, we propose two objective visual quality metrics for textured meshes, relying on the optimal combinations of geometry and texture quality measures. These proposed perceptual metrics outperform their counterparts in term of the correlation with the human judgment

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Shahid, Muhammad. "Methods for Objective and Subjective Video Quality Assessment and for Speech Enhancement." Doctoral thesis, Blekinge Tekniska Högskola [bth.se], Faculty of Engineering - Department of Applied Signal Processing, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-00603.

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The overwhelming trend of the usage of multimedia services has raised the consumers' awareness about quality. Both service providers and consumers are interested in the delivered level of perceptual quality. The perceptual quality of an original video signal can get degraded due to compression and due to its transmission over a lossy network. Video quality assessment (VQA) has to be performed in order to gauge the level of video quality. Generally, it can be performed by following subjective methods, where a panel of humans judges the quality of video, or by using objective methods, where a computational model yields an estimate of the quality. Objective methods and specifically No-Reference (NR) or Reduced-Reference (RR) methods are preferable because they are practical for implementation in real-time scenarios. This doctoral thesis begins with a review of existing approaches proposed in the area of NR image and video quality assessment. In the review, recently proposed methods of visual quality assessment are classified into three categories. This is followed by the chapters related to the description of studies on the development of NR and RR methods as well as on conducting subjective experiments of VQA. In the case of NR methods, the required features are extracted from the coded bitstream of a video, and in the case of RR methods additional pixel-based information is used. Specifically, NR methods are developed with the help of suitable techniques of regression using artificial neural networks and least-squares support vector machines. Subsequently, in a later study, linear regression techniques are used to elaborate the interpretability of NR and RR models with respect to the selection of perceptually significant features. The presented studies on subjective experiments are performed using laboratory based and crowdsourcing platforms. In the laboratory based experiments, the focus has been on using standardized methods in order to generate datasets that can be used to validate objective methods of VQA. The subjective experiments performed through crowdsourcing relate to the investigation of non-standard methods in order to determine perceptual preference of various adaptation scenarios in the context of adaptive streaming of high-definition videos. Lastly, the use of adaptive gain equalizer in the modulation frequency domain for speech enhancement has been examined. To this end, two methods of demodulating speech signals namely spectral center of gravity carrier estimation and convex optimization have been studied.

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Saidi, Inès. "Analyse et modélisation de la qualité perçue des applications de visiophonie." Thesis, Rennes, INSA, 2018. http://www.theses.fr/2018ISAR0013/document.

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Dans un contexte fortement concurrentiel, l'un des principaux enjeux pour les opérateurs et les fournisseurs de services de visiophonie est de garantir aux utilisateurs une qualité d'expérience (QoE) optimale. Il existe un fort besoin d'une mesure qui reflète la satisfaction et la perception des utilisateurs de ces services. La qualité audiovisuelle d'un appel vidéo doit être contrôlée pour répondre à deux besoins principaux. Le premier concerne la planification de nouvelles technologies en cours de développement. Le second est axé sur le contrôle des communications existantes en évaluant la qualité des services offerts. Aujourd'hui, deux approches sont utilisées pour évaluer la qualité audiovisuelle : les tests subjectifs en collectant des notes données par des participants sur des échelles de qualité, après visualisation et écoute de séquences audiovisuelles et les métriques objectives basées sur des algorithmes automatiques d'évaluation de la qualité d'un signal audio, vidéo ou audiovisuel. Concernant les services de téléphonie, des décennies de recherche, de standardisation et d'exploitation des réseaux ont permis aux opérateurs de maîtriser les outils de diagnostic et de déterminer les métriques représentatives de la qualité vocale. Cependant, les méthodes de mesure de la qualité audiovisuelle des services conversationnels ne sont pas encore matures et peu exploitées par les opérateurs de télécommunication. Le présent travail est centré sur la recherche de métriques représentatives de la perception de la qualité des nux associés aux services de visiophonie et de visioconférence. Ces métriques objectives sont calculées à partir du signal audio et vidéo. Des tests subjectifs sont menés afin de collecter le jugement des utilisateurs du service sur la qualité perçue en fonction de différents niveaux de dégradations. Nous avons étudié l'impact des conditions réseau (perte de paquet, gigue et désynchronisation) sur la QoE d'un appel vidéo. Le principe général est ensuite d'établir une corrélation forte entre les métriques objectives sélectionnées et la qualité perçue telle qu'elle est exprimée par les utilisateurs. Les résultats ont montré que les nouvelles métriques de qualité globale audiovisuelle qui prennent en compte l'aspect temporel de la vidéo sont plus performantes que les métriques basées qualité d'images. D'autre part l'utilisation d'une approche machine learning représente une solution pour générer un modèle de prédiction de la qualité globale à partir des métriques de dégradation (flou, pixellisation, gel d'images, ... ) In 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, ... )

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Budhrani, Pinky H. "Race/Ethnicity, Subjective and Objective Sleep Quality, Physical and Psychological Symptoms in Breast Cancer Survivors." Scholar Commons, 2013. http://scholarcommons.usf.edu/etd/4645.

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Breast cancer is a major health problem and comprises the largest population of cancer survivors in the United States, estimated at 2.9 million women, accounting for 22% of all cancer survivors (National Cancer Institute, 2013). The advances in breast cancer screening, diagnosis and treatment has increased the importance of survivorship needs. A major concern among breast cancer survivors (BCS) is sleep disturbances. This study used an innovative approach to examine ethnic and racial disparities in sleep disturbances present in BCS. In addition, this study also explored sleep disturbances across different races/ethnicities. This study was a secondary data analysis of baseline data from the supplement study of the MBSR Symptom Cluster Trial for Breast Cancer Survivors/ 1R01CA131080, conducted by Dr. Lengacher. Sleep was measured using the Pittsburgh Sleep Quality Index, sleep diary (subjective), and sleep actigraphy (objective). The sample consists of 79 women who had been diagnosed with breast cancer (Stage 0, I, II, III), completed lumpectomy and/or mastectomy, and were within 2 weeks to 2 years post radiation and/or chemotherapy treatment. The aims for this study were to: 1) explore racial/ethnic differences in objectively measured sleep patterns among BCS; 2) estimate and compare the correlation between objective and subjective sleep quality by racial/ethnic groups among BCS; 3) examine which sleep actigraphy measure appears to have the strongest relationship with physical and psychological symptoms; and 4) explore whether these relationships (i.e. between objective sleep and self-reported symptoms) appear to be modified by race/ethnicity. The first aim was conducted using analysis of variance (ANOVA) and analysis of covariance (ANCOVA). Results indicated that white, non Hispanic BCS had improved objective sleep quality compared to minority BCS. The second aim was conducted using Pearson's correlation with significant correlations found between subjective and objective sleep onset latency (r= .310, p= .016), and total sleep time (TST) (r= .328, p= .011) for the white, non-Hispanic group. The third aim was conducted using Pearson's correlation with significant correlations between sleep onset latency and depression (r= .247, p= .029); sleep efficiency and depression (r= -.233, p= .040); sleep efficiency and fatigue (r= -.207, p= .045); and WASO and pain (r= .277, p= .014). There were no significant correlations between the anxiety score and actigraphy parameters. Using the significant correlations from the results of the third aim, multiple regression analysis was conducted with age as a covariate to test the fourth aim. The main effect of depression on sleep efficiency was significant (p= .044) with less depression associated with higher sleep efficiency. The interaction term, depression by race/ethnicity, had a non-significant effect on sleep efficiency (p= .299). The main effect of pain on WASO was significant (p= .008), and increased pain was associated with longer WASO. The interaction term, race/ethnicity by pain, had a non-significant effect on WASO (p= .148). The main effect of depression predicting sleep onset latency was significant (p= .027), and the interaction term, depression by race/ethnicity, had a trend towards a significant effect (p= .092) on predicting sleep onset latency. The interaction between depression and race/ethnicity predicting sleep onset latency was further decomposed using multiple regression. The average sleep onset latency was longer in the minority group with high depression levels (42 minutes) compared to the white, non-Hispanics with high depression levels (29 minutes). Race modified the effect of depression on sleep onset latency in this sample of BCS. These finding suggest that the experience of objective sleep disturbances is different among races/ethnicities. Additional research is needed to further explore racial/ethnic differences in subjective and objective sleep disturbances and its impact on physical and psychological symptoms among BCS. As the number of BCS continue to rise, it is becoming increasingly important to recognize sleep disturbances and their potential physical and psychological effects early in BCS, specifically in different races and ethnicities. It is anticipated that these findings may contribute to improved symptom management for women of different races and ethnicities.

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Swenson, Andrea Valeria Roets. "Making Romantic Relationships Tick: Objective and Subjective Time Use and Relationship Quality Among Business Owners." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/70908.

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This study assesses the contextual aspect of working in a family business on intimate relationships. Guided by principles of ecological theory, this study explores the unique situation of individuals who work with an intimate partner in a business they own and how this situation manifests itself in their close relationship. Individuals in a family business are confronted with a potentially unique family-work experience, especially for spouses/partners who work together in a business. It is hypothesized that objective and subjective work time influence couple relationship quality. Six specific hypotheses centered on the connection between family and work microsystems as well as the influence of macrosystem beliefs regarding family, work, and gender were assessed by regression analysis. Ninety-nine individuals completed a demographic and daily diary online. The sample was 52.53% men, 78.79% White, and educated (63.63% held at least Bachelor degrees). The majority of the sample was legally married (91.92%), with an average relationship length of 16.20 years (SD = 12.74 years). Regression analyses revealed limited support for the hypotheses. For people in family businesses, working more hours was associated with greater withdrawal from their intimate partner. Perceiving work time as sad was linked to more withdrawal from partner and more anger with partner, but not linked with feelings of closeness to partner. People who felt time at work as appreciated reported feeling closer to their intimate partner. The more respondents believed it was meaningful to distinguish between work and family, the less closeness to their partner they reported. Finally, age was significant for relationship quality, with younger individuals reporting more withdrawal and anger with partner and less closeness to their partner than did older individuals. This study contributes to research exploring the connection between family and work among individuals who work together in family businesses. While objective work time was associated with the measure of withdrawal from a partner, objective work time did not significantly contribute to the report of anger with a partner or closeness to a partner. Overall, how individuals felt during work time had an effect on their spousal/partner relationship, with feeling sad at work associated with more relationship withdrawal and anger, and feeling appreciated at work associated with more closeness. Limited support for the model suggests there may be unique processes of work and family operating within family businesses. Although work and family microsystems were connected in this study of family business owners, the links between work and family were different from previous research on dual- and single-earner families. Future research should untangle the processes through which work and family and time are connected, with attention to larger cultural influences, particularly how individuals within family businesses do work and family and how families ascribe to and enact gender within family businesses. In addition, further research should assess the degree to which microsystems can be differentiated in populations characterized by an extreme mesosystem connection between work and family. Ph. D.

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Khaustova, Darya. "Objective assessment of stereoscopic video quality of 3DTV." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S021/document.

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Le niveau d'exigence minimum pour tout système 3D (images stéréoscopiques) est de garantir le confort visuel des utilisateurs. Le confort visuel est un des trois axes perceptuels de la qualité d'expérience (QoE) 3D qui peut être directement lié aux paramètres techniques du système 3D. Par conséquent, le but de cette thèse est de caractériser objectivement l'impact de ces paramètres sur la perception humaine afin de contrôler la qualité stéréoscopique. La première partie de la thèse examine l'intérêt de prendre en compte l'attention visuelle des spectateurs dans la conception d'une mesure objective de qualité 3D. Premièrement, l'attention visuelle en 2D et 3D sont comparées en utilisant des stimuli simples. Les conclusions de cette première expérience sont validées en utilisant des scènes complexes avec des disparités croisées et décroisées. De plus, nous explorons l'impact de l'inconfort visuel causé par des disparités excessives sur l'attention visuelle. La seconde partie de la thèse est dédiée à la conception d'un modèle objectif de QoE pour des vidéos 3D, basé sur les seuils perceptuels humains et le niveau d'acceptabilité. De plus nous explorons la possibilité d'utiliser la modèle proposé comme une nouvelle échelle subjective. Pour la validation de ce modèle, des expériences subjectives sont conduites présentant aux sujets des images stéréoscopiques fixes et animées avec différents niveaux d'asymétrie. La performance est évaluée en comparant des prédictions objectives avec des notes subjectives pour différents niveaux d'asymétrie qui pourraient provoquer un inconfort visuel The minimum requirement for any 3D (stereoscopic images) system is to guarantee visual comfort of viewers. Visual comfort is one of the three primary perceptual attributes of 3D QoE, which can be linked directly with technical parameters of a 3D system. Therefore, the goal of this thesis is to characterize objectively the impact of these parameters on human perception for stereoscopic quality monitoring. The first part of the thesis investigates whether visual attention of the viewers should be considered when designing an objective 3D quality metrics. First, the visual attention in 2D and 3D is compared using simple test patterns. The conclusions of this first experiment are validated using complex stimuli with crossed and uncrossed disparities. In addition, we explore the impact of visual discomfort caused by excessive disparities on visual attention. The second part of the thesis is dedicated to the design of an objective model of 3D video QoE, which is based on human perceptual thresholds and acceptability level. Additionally we explore the possibility to use the proposed model as a new subjective scale. For the validation of proposed model, subjective experiments with fully controlled still and moving stereoscopic images with different types of view asymmetries are conducted. The performance is evaluated by comparing objective predictions with subjective scores for various levels of view discrepancies which might provoke visual discomfort

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Ansari, Yousuf Hameed, and Sohaib Ahmed Siddiqui. "Quality Assessment for HEVC Encoded Videos: Study of Transmission and Encoding Errors." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-13656.

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There is a demand for video quality measurements in modern video applications specifically in wireless and mobile communication. In real time video streaming it is experienced that the quality of video becomes low due to different factors such as encoder and transmission errors. HEVC/H.265 is considered as one of the promising codecs for compression of ultra-high definition videos. In this research, full reference based video quality assessment is performed. The raw format reference videos have been taken from Texas database to make test videos data set. The videos are encoded using HM9 reference software in HEVC format. Encoding errors has been set during the encoding process by adjusting the QP values. To introduce packet loss in the video, the real-time environment has been created. Videos are sent from one system to another system over UDP protocol in NETCAT software. Packet loss is induced with different packet loss ratios into the video using NETEM software. After the compilation of video data set, to assess the video quality two kind of analysis has been performed on them. Subjective analysis has been carried on different human subjects. Objective analysis has been achieved by applying five quality matrices PSNR, SSIM, UIQI, VFI and VSNR. The comparison is conducted on the objective measurement scores with the subjective and in the end results deduce from classical correlation methods.

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Kaya, Safak. "Quality Of Life In Turkey: A Comparative Analysis With The European Union Member States." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/3/12607932/index.pdf.

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This study aims to describe the quality of life of Turkey in comparison with the European Union Member States including the other candidate countries Bulgaria and Romania. The main question in the study is to determine where Turkey stands in terms of quality of life domains in the membership process to the European Union. For this aim, &ldquo The European Quality of Life Survey&rdquo that has been launched in 2003 including 28 countries in Europe has been used. The survey consists of eight life domains including different objective and subjective indicators to measure the quality of life in these countries. The findings revealed that although Turkey displays similar patterns with the other candidate countries, it lags behind the European Union Member States in most of these eight quality of life domains.

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14

Suresh, Nitin. "Mean Time Between Visible Artifacts in Visual Communications." Diss., Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/16238.

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As digital communication of television content becomes more pervasive, and as networks supporting such communication become increasingly diverse, the long-standing problem of assessing video quality by objective measurements becomes particularly important. Content owners as well as content distributors stand to benefit from rapid objective measurements that correlate well with subjective assessments, and further, do not depend on the availability of the original reference video. This thesis investigates different techniques of subjective and objective video evaluation. Our research recommends a functional quality metric called Mean Time Between Failures (MTBF) where failure refers to video artifacts deemed to be perceptually noticeable, and investigates objective measurements that correlate well with subjective evaluations of MTBF. Work has been done for determining the usefulness of some existing objective metric by noting their correlation with MTBF. The research also includes experimentation with network-induced artifacts, and a study on statistical methods for correlating candidate objective measurements with the subjective metric. The statistical significance and spread properties for the correlations are studied, and a comparison of subjective MTBF with the existing subjective measure of MOS is performed. These results suggest that MTBF has a direct and predictable relationship with MOS, and that they have similar variations across different viewers. The research is particularly concerned with the development of new no-reference objective metrics that are easy to compute in real time, as well as correlate better than current metrics with the intuitively appealing MTBF measure. The approach to obtaining greater subjective relevance has included the study of better spatial-temporal models for noise-masking and test data pooling in video perception. A new objective metric, 'Automatic Video Quality' metric (AVQ) is described and shown to be implemented in real time with a high degree of correlation with actual subjective scores, with the correlation values approaching the correlations of metrics that use full or partial reference. This is metric does not need any reference to the original video, and when used to display MPEG2 streams, calculates and indicates the video quality in terms of MTBF. Certain diagnostics like the amount of compression and network artifacts are also shown.

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15

Zerman, Emin. "Evaluation et analyse de la qualité vidéo à haute gamme dynamique." Electronic Thesis or Diss., Paris, ENST, 2018. http://www.theses.fr/2018ENST0003.

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Au cours de la dernière décennie, la technologie de l’image et de la vidéo à haute gamme dynamique (High dynamic range - HDR) a attiré beaucoup d’attention, en particulier dans la communauté multimédia. Les progrés technologiques récents ont facilité l’acquisition, la compression et la reproduction du contenu HDR, ce qui a mené à la commercialisation des écrans HDR et à la popularisation du contenu HDR. Dans ce contexte, la mesure de la qualité du contenu HDR joue un rôle fondamental dans l’amélioration de la chaîne de distribution du contenu ainsi que des opérations qui la composent, telles que la compression et l’affichage. Cependant, l’évaluation de la qualité visuelle HDR présente de nouveaux défis par rapport au contenu à gamme dynamique standard (Standard dynamic range -SDR). Le premier défi concerne les nouvelles conditions introduites par la reproduction du contenu HDR, par ex. l’augmentation de la luminosité et du contraste. Même si une reproduction exacte de la luminance d’une scène n’est pas nécessaire pour la plupart des cas pratiques, une estimation précise de la luminance émise est cependant nécessaire pour les mesures d’évaluation objectives de la qualité HDR. Afin de comprendre les effets du rendu d’affichage sur la perception de la qualité, un algorithme permettant de reproduire très précisement une image HDR a été développé et une expérience subjective a été menée pour analyser l’impact de différents rendus sur l’évaluation subjective et objective de la qualité HDR. En outre, afin de comprendre l’impact de la couleur avec la luminosité accrue des écrans HDR, les effets des différents espaces de couleurs sur les performances de compression vidéo HDR ont également été analysés dans une autre étude subjective. Un autre défi consiste à estimer objectivement la qualité du contenu HDR, en utilisant des ordinateurs et des algorithmes. Afin de relever ce défi, la thèse procède à l’évaluation des performances des métriques de qualité d’image HDR avec référence (Full reference-FR). Les images HDR ont une plus grande plage de luminosité et des valeurs de contraste plus élevées. Etant donné que la plupart des métriques de qualité d’image sont développées pour les images SDR, elles doivent être adaptées afin d’estimer la qualité des images HDR. Différentes méthodes d’adaptation ont été utilisées pour les mesures SDR, et elles ont été comparées avec les métriques de qualité d’image existantes développées exclusivement pour les images HDR. De plus, nous proposons une nouvelle méthode d’évaluation des métriques objectives basée sur une nouvelle approche de classification. Enfin, nous comparons les scores de qualité subjectifs acquis en utilisant différentes méthodologies de test subjectives. L’évaluation subjective de la qualité est considérée comme le moyen le plus efficace et le plus fiable d’obtenir des scores de qualité «vérité-terrain» pour les stimuli sélectionnés, et les scores moyens d’opinion (Mean opinion scores-MOS) obtenus sont les valeurs auxquelles les métriques objectives sont entraînées pour correspondre. En fait, de fortes divergences peuvent facilement être rencontrés lorsque différentes bases de données de qualité multimédia sont considérées. Afin de comprendre la relation entre les valeurs de qualité acquises à l’aide de différentes méthodologies, la relation entre les valeurs MOS et les résultats des comparaisons par paires rééchellonés (Pairwise comparisons - PC) a été comparée. A cette fin, une série d’expériences ont été menées entre les méthodologies double stimulus impairment scale (DSIS) et des comparaisons par paires. Nous proposons d’inclure des comparaisons inter-contenu dans les expériences PC afin d’améliorer les performances de rééchelonnement et de réduire la variance inter-contenu ainsi que les intervalles de confiance. Les scores de PC rééchellonés peuvent également être utilisés pour des scénarios subjectifs d’évaluation de la qualité multimédia autres que le HDR In the last decade, high dynamic range (HDR) image and video technology gained a lot of attention, especially within the multimedia community. Recent technological advancements made the acquisition, compression, and reproduction of HDR content easier, and that led to the commercialization of HDR displays and popularization of HDR content. In this context, measuring the quality of HDR content plays a fundamental role in improving the content distribution chain as well as individual parts of it, such as compression and display. However, HDR visual quality assessment presents new challenges with respect to the standard dynamic range (SDR) case. The first challenge is the new conditions introduced by the reproduction of HDR content, e.g. the increase in brightness and contrast. Even though accurate reproduction is not necessary for most of the practical cases, accurate estimation of the emitted luminance is necessary for the objective HDR quality assessment metrics. In order to understand the effects of display rendering on the quality perception, an accurate HDR frame reproduction algorithm was developed, and a subjective experiment was conducted to analyze the impact of different display renderings on subjective and objective HDR quality evaluation. Additionally, in order to understand the impact of color with the increased brightness of the HDR displays, the effects of different color spaces on the HDR video compression performance were also analyzed in another subjective study. Another challenge is to estimate the quality of HDR content objectively, using computers and algorithms. In order to address this challenge, the thesis proceeds with the performance evaluation of full-reference (FR) HDR image quality metrics. HDR images have a larger brightness range and higher contrast values. Since most of the image quality metrics are developed for SDR images, they need to be adapted in order to estimate the quality of HDR images. Different adaptation methods were used for SDR metrics, and they were compared with the existing image quality metrics developed exclusively for HDR images. Moreover, we propose a new method for the evaluation of metric discriminability based ona novel classification approach. Motivated by the need to fuse several different quality databases, in the third part of the thesis, we compare subjective quality scores acquired by using different subjective test methodologies. Subjective quality assessment is regarded as the most effective and reliable way of obtaining “ground-truth” quality scores for the selected stimuli, and the obtained mean opinion scores (MOS) are the values to which generally objective metrics are trained to match. In fact, strong discrepancies can easily be notified across databases when different multimedia quality databases are considered. In order to understand the relationship between the quality values acquired using different methodologies, the relationship between MOS values and pairwise comparisons (PC) scaling results were compared. For this purpose, a series of experiments were conducted using double stimulus impairment scale (DSIS) and pairwise comparisons subjective methodologies. We propose to include cross-content comparisons in the PC experiments in order to improve scaling performance and reduce cross-content variance as well as confidence intervals. The scaled PC scores can also be used for subjective multimedia quality assessment scenarios other than HDR

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Axelson, Per-Erik. "Quality Measures of Halftoned Images (A Review)." Thesis, Linköping University, Department of Science and Technology, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-1138.

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This study is a thesis for the Master of Science degree in Media Technology and Engineering at the Department of Science and Technology, Linkoping University. It was accomplished from November 2002 to May 2003. Objective image quality measures play an important role in various image processing applications. In this paper quality measures applied on halftoned images are aimed to be in focus. Digital halftoning is the process of generating a pattern of binary pixels that create the illusion of a continuous- tone image. Algorithms built on this technique produce results of very different quality and characteristics. To evaluate and improve their performance, it is important to have robust and reliable image quality measures. This literature survey is to give a general description in digital halftoning and halftone image quality methods.

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Servetkienė, Vaida. "Gyvenimo kokybės daugiadimensis vertinimas, identifikuojant kritines sritis." Doctoral thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.library.lt/obj/LT-eLABa-0001:E.02~2013~D_20131115_113802-40756.

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Disertacijoje nagrinėjama aktuali gyvenimo kokybės vertinimo problema. Mokslinėje literatūroje vis dar nėra vienodo gyvenimo kokybės suvokimo ir mokslinio apibrėžimo. Kiekvienas asmuo šiai sąvokai gali suteikti savo prasminį atspalvį, tačiau moksle gyvenimo kokybė turi būti konkrečiais rodikliais išreiškiama ir matuojama sąvoka, susijusi su visuomenės gerove konkrečioje šalyje. Šio darbo tyrimo objektas yra gyvenimo kokybės vertinimas. Disertacijos tikslas – išanalizavus mokslinius tarpdisciplininius požiūrius į gyvenimo kokybės vertinimą, parengti daugiadimensį gyvenimo kokybės vertinimo modelį ir nustatyti kritines jos sritis Lietuvoje. Darbe atlikta gyvenimo kokybės apibrėžties, koncepcijų ir praktikoje taikomų gyvenimo kokybės vertinimo metodų lyginamoji analizė, konceptualizuota gyvenimo kokybės sąvoka, ją traktuojant kaip ekonomikos mokslo tyrimo objektą, atspindintį valstybės vykdomos ekonominės politikos efektyvumą, nustatytos pagrindinės gyvenimo kokybės sritys, pateikta gyvenimo kokybės koncepcija ir pasiūlyti jos vertinimo metodologiniai principai, sudarytas daugiadimensis gyvenimo kokybės vertinimo modelis, jį taikant, įvertinta Lietuvos gyventojų gyvenimo kokybė ES šalių kontekste ir nustatytos kritinės jos sritys. The dissertation examines the topical issue of assessment of the quality of life. Scientific literature still does not offer a uniform perception and scientific definition of the quality of life. Every person can provide this concept with his own interpretation, but in science the quality of life must be a concept expressed by means of specific indicators and measured in relation to the welfare of the population in a specific country. The object of research in this dissertation is the assessment of the quality of life. The aim of the dissertation is, upon analysing interdisciplinary scientific approaches to assessment of the quality of life, to develop a multidimensional model of assessment of the quality of life and to identify the critical areas of the quality of life in Lithuania. The author of the dissertation has carried out a comparative analysis of the definition and conceptions of the quality of life and the quality of life assessment methods employed in practice, conceptualised the concept of the quality of life treating it as an object of economic research which reflects the efficiency of the economic policy of the state, identified the key areas of the quality of life, provided a conception of the quality of life and proposed methodological principles for its assessment, developed a multidimensional quality of life assessment model and, by applying the model, evaluated the quality of life of the Lithuanian population in the context of the EU Member States and... [to full text]

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18

Klejmová, Eva. "Měření kvality pro HEVC." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2014. http://www.nusl.cz/ntk/nusl-220577.

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This diploma thesis deals with standard objective and subjective video quality assessments and with analysis of their applicability to HEVC. Also basic description of video compression standard H.265/HEVC is presented. The main focus of the thesis is a creation of the database of compressed video sequences. Important parameters and features of the reference encoder HM-12 are discussed. Selected methods of objective video quality assessments are implemented on the created database. A part of this thesis is also a suggestion of method for objective video quality assessment, application of this method and associated data collection. Final data is statistically analyzed and it’s correlation with objective tests is discussed.

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19

Vlad, Raluca Ioana. "Une méthode pour l'évaluation de la qualité des images 3D stéréoscopiques." Phd thesis, Université de Grenoble, 2013. http://tel.archives-ouvertes.fr/tel-00925280.

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Dans le contexte d'un intérêt grandissant pour les systèmes stéréoscopiques, mais sans méthodes reproductible pour estimer leur qualité, notre travail propose une contribution à la meilleure compréhension des mécanismes de perception et de jugement humains relatifs au concept multi-dimensionnel de qualité d'image stéréoscopique. Dans cette optique, notre démarche s'est basée sur un certain nombre d'outils : nous avons proposé un cadre adapté afin de structurer le processus d'analyse de la qualité des images stéréoscopiques, nous avons implémenté dans notre laboratoire un système expérimental afin de conduire plusieurs tests, nous avons crée trois bases de données d'images stéréoscopiques contenant des configurations précises et enfin nous avons conduit plusieurs expériences basées sur ces collections d'images. La grande quantité d'information obtenue par l'intermédiaire de ces expérimentations a été utilisée afin de construire un premier modèle mathématique permettant d'expliquer la perception globale de la qualité de la stéréoscopie en fonction des paramètres physiques des images étudiée.

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Xiao, Yao. "User perceived video quality modelling on mobile devices for Vp9 and H265 encoders." Thesis, Queensland University of Technology, 2015. https://eprints.qut.edu.au/81842/1/Yao_Xiao_Thesis.pdf.

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This study constructs performance prediction models to estimate the end-user perceived video quality on mobile devices for the latest video encoding techniques –VP9 and H.265. Both subjective and objective video quality assessments were carried out for collecting data and selecting the most desirable predictors. Using statistical regression, two models were generated to achieve 94.5% and 91.5% of prediction accuracies respectively, depending on whether the predictor derived from the objective assessment is involved. These proposed models can be directly used by media industries for video quality estimation, and will ultimately help them to ensure a positive end-user quality of experience on future mobile devices after the adaptation of the latest video encoding technologies.

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Rajasekaran, Arunkumar, and Velanginichakravarthy Cherry. "Effect of Network OFF Times on Web Browsing QoE." Thesis, Blekinge Tekniska Högskola, Sektionen för datavetenskap och kommunikation, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-3420.

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The web user usually expects a better Quality of Service (QoS) from the Internet Service Provider (ISP) for the best Quality of Experience (QoE). User satisfaction and feedback is one of the most important factors for the service providers to determine their QoS and improve the network performance. Service providers are more interested in QoE to provide a better service to their users to maintain their customers in the competitive market. Since there is no much study work conducted in the QoE on web browsing, only a few studies are available for getting user feedbacks. So the ISP is facing a difficulty in the assessment of the user experience in the real time network. Network level performance can be measured by the ISP for QoS and user feedback can be measured for QoE. There is no study available on relating both the QoS and QoE. Relating the network level performance and the user perception is a difficult task for the service providers. In this study we have correlated both the network level traffic performance and user experience. In our experiment the user QoE is tested by applying various off times applied to some specific packets. Our main aim is to evaluate the network level performance and correlate it with the user feedback. Later, on focusing the network level performance network traffic is analyzed for different sessions with off times applied in DNS response, Base file response and Object response. We have discussed in the results by correlating the different sessions of off times that we applied and user feedback MOS. We have also discussed the relation of the network off time in the network with the number of requests sent from client to server and the number of flag bits like SYN & ACK, FIN & ACK and RST flags between the client and server. In this study we also discussed about the user feedback and how the user suffers on varying long response time. Finally, we conclude from our results about the major factor that affects the user feedback and the user interest in using the service again. chakri PH: +918008316269

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Sanches, Silvio Ricardo Rodrigues. "Avaliação objetiva de qualidade de segmentação." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/3/3141/tde-26062014-111553/.

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A avaliação de qualidade de segmentação de vídeos tem se mostrado um problema pouco investigado no meio científico. Apesar disso, estudos recentes na área resultaram em algumas métricas que têm como finalidade avaliar objetivamente a qualidade da segmentação produzida pelos algoritmos. Tais métricas consideram as diferentes formas em que os erros ocorrem (fatores perceptuais) e seus parâmetros são ajustados de acordo com a aplicação em que se pretende utilizar os vídeos segmentados. Neste trabalho apresentam-se: i) uma avaliação da métrica que representa o estado-da-arte, demonstrando que seu desempenho varia de acordo com o algoritmo; ii) um método subjetivo para avaliação de qualidade de segmentação; e iii) uma nova métrica perceptual objetiva, derivada do método subjetivo aqui proposto, capaz de encontrar o melhor ajuste dos parâmetros de dois algoritmos de segmentação encontrados na literatura, quando os vídeos por eles segmentados são utilizados na composição de cenas em ambientes de Teleconferência Imersiva. Assessment of video segmentation quality is a problem seldom investigated by the scientific community. Nevertheless, recent studies presented some objective metrics to evaluate algorithms. Such metrics consider different ways in which segmentation errors occur (perceptual factors) and its parameters are adjusted according to the application for which the segmented frames are intended. In this work: i) we demonstrate empirically that the performance of existing metrics changes according to the segmentation algorithm; ii) we developed a subjective method to evaluate segmentation quality; and iii) we contribute with a new objective metric derived on the basis of experiments from subjective method in order to adjust the parameters of two bilayer segmentation algorithms found in the literature when these algorithms are used for compose scenes in Immersive Teleconference environments.

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Nouri, Nedia. "Évaluation de la qualité et transmission en temps-réel de vidéos médicales compressées : application à la télé-chirurgie robotisée." Thesis, Vandoeuvre-les-Nancy, INPL, 2011. http://www.theses.fr/2011INPL049N/document.

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L'évolution des techniques chirurgicales, par l'utilisation de robots, permet des interventions mini-invasives avec une très grande précision et ouvre des perspectives d'interventions chirurgicales à distance, comme l'a démontré la célèbre expérimentation « Opération Lindbergh » en 2001. La contrepartie de cette évolution réside dans des volumes de données considérables qui nécessitent des ressources importantes pour leur transmission. La compression avec pertes de ces données devient donc inévitable. Celle-ci constitue un défi majeur dans le contexte médical, celui de l'impact des pertes sur la qualité des données et leur exploitation. Mes travaux de thèse concernent l'étude de techniques permettant l'évaluation de la qualité des vidéos dans un contexte de robotique chirurgicale. Deux approches méthodologiques sont possibles : l'une à caractère subjectif et l'autre à caractère objectif. Nous montrons qu'il existe un seuil de tolérance à la compression avec pertes de type MPEG2 et H.264 pour les vidéos chirurgicales. Les résultats obtenus suite aux essais subjectifs de la qualité ont permis également de mettre en exergue une corrélation entre les mesures subjectives effectuées et une mesure objective utilisant l'information structurelle de l'image. Ceci permet de prédire la qualité telle qu'elle est perçue par les observateurs humains. Enfin, la détermination d'un seuil de tolérance à la compression avec pertes a permis la mise en place d'une plateforme de transmission en temps réel sur un réseau IP de vidéos chirurgicales compressées avec le standard H.264 entre le CHU de Nancy et l'école de chirurgie The digital revolution in medical environment speeds up development of remote Robotic-Assisted Surgery and consequently the transmission of medical numerical data such as pictures or videos becomes possible. However, medical video transmission requires significant bandwidth and high compression ratios, only accessible with lossy compression. Therefore research effort has been focussed on video compression algorithms such as MPEG2 and H.264. In this work, we are interested in the question of compression thresholds and associated bitrates are coherent with the acceptance level of the quality in the field of medical video. To evaluate compressed medical video quality, we performed a subjective assessment test with a panel of human observers using a DSCQS (Double-Stimuli Continuous Quality Scale) protocol derived from the ITU-R BT-500-11 recommendations. Promising results estimate that 3 Mbits/s could be sufficient (compression ratio aroundthreshold compression level around 90:1 compared to the original 270 Mbits/s) as far as perceived quality is concerned. Otherwise, determining a tolerance to lossy compression has allowed implementation of a platform for real-time transmission over an IP network for surgical videos compressed with the H.264 standard from the University Hospital of Nancy and the school of surgery

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Ševčík, Martin. "Modelování vlastností modelu HVS v Matlabu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217656.

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In theoretical part Diploma thesis deals with the model of human vision HVS (Human Visual System), which can be used for image quality assessment in TV technique area. It has been described calculations of selected JND (Just Noticeable Difference) metrics, used in evaluation of HVS. In practical part of the thesis it has been suggested and realized simulation model in Matlab, which may be used for evaluation of three JND metrics from color and grayscale images and evaluation in spatial a frequency domain. Results of JND models have been compared to another objective image quality evaluation metrics (MSE, NMSE, SNR and PSNR). For interpretation of dependencies it has been used images with different defined content.

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Iveynat, Nermin. "Urban Transformation Projects In Squatter Settlements: The Case Of Ankara, Sentepe Urban Transformation Project." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12610278/index.pdf.

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Squatter settlements still represent the worst of urban poverty and inequality in Turkey. Yet the world has the resources, know-how and power to reach the best experiences. Urban transformation has become a topic of growing interest in many cities in the world. It has also become popular in Turkish cities and the most common urban transformation projects in Turkey are implemented in squatter settlements. However, while the scope of urban transformation interventions generally aims to improve the quality of urban life, increase the livability of cities in various aspects and provide cities with the ability to trace other cities in both national scale and the globalized world, it is still a question mark whether urban transformation projects are successful enough in improving every aspects of urban life and fulfill the promise of development for their inhabitants particularly by improving the lives of the poor and promoting equity. In this respect, this research tries to identify the success level of urban transformation projects implemented in squatter settlements. Since many urban transformation projects implemented extensively in squatter settlements in Turkey, generally with the aim of increasing the density of buildings and gaining rent over these areas, the concept of urban transformation has an indisputable importance to be researched. The key purpose of this thesis is to reveal the components of quality of urban and community life in terms of physical, environmental, social, and economic dimensions and provide both objective (quantitative) and subjective (qualitative) approaches over these components to assess the success level of Sentepe Urban Transformation Project and increase the success level of urban transformation projects in squatter settlements. This research will reveal up the degree to which Sentepe Urban Transformation Project will respond to the requirements of the criteria of urban quality of life. Further, this research aims to provide inputs for the next urban transformation interventions to guarantee the satisfaction of urban life and well-beings of local community in terms of various issues related to urban life. The key proposition of this research is &amp #8216 The success level of an urban transformation project depends on how far it provides an urban quality of life whose main indicators are both physical, environmental, economic, and social and objective and subjective aspects.&amp #8217 This thesis utilizes the experiences of one of well known project in the world which provides quality of urban and community life due to the multi-dimensional characteristics of urban transformation. Then, as stated above, the research focuses on &amp #8216 Sentepe Urban Transformation Project&amp #8217 in Ankara as a field survey and evaluate the success level of this project due to the success determinants proposed by this thesis. Finally, this thesis intends to increase the success level of urban transformation projects in squatter settlements and puts forward the success level of &amp #8216 Sentepe Urban Transformation Project&amp #8217 in terms of providing well-being of inhabitants in accordance with quality of urban life indicators and four dimensions of urban regeneration physical, environmental, economic, and social.

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Begazo, Dante Coaquira. "Avaliação objetiva e subjetiva de qualidade de vídeo via rede IP com variação de atraso." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-16072013-122005/.

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Atualmente existe uma grande variedade de serviços de telecomunicações focados na transmissão de voz, vídeo e dados através de redes complexas, embora, em muitos casos, o usuário final não seja atendido com um nível de qualidade aceitável. Neste trabalho, se avalia como o serviço de streaming de vídeo em uma rede com protocolo Internet (IP) pode ser afetado por uma condição adversa da rede, tal como a variação de atraso (jitter). São mostrados os resultados de avaliações objetivas e subjetivas de streaming de vídeo que indicam que a qualidade de vídeo é diretamente afetada por fatores de degradação da rede IP como a variação de atraso de pacotes. Além disso, se verifica que cenas de maior movimento também são mais afetadas pela variação de atraso. Para a realização dos testes, utiliza-se um cenário de emulação de rede isolado, no qual são parametrizadas diferentes condições de rede. Assim, no canal de transmissão são configurados diversos valores de variação de atraso, obtendo-se uma Base de Dados de vídeos com diferentes graus de degradação de qualidade. Estes vídeos são avaliados utilizando métodos subjetivos: Índice por Categorias Absolutas (ACR - Absolute Category Rating) e Índice por Categorias de Degradação (DCR - Degradation Category Rating) e métricas objetivas: Relação Sinal-Ruído de Pico (PSNR - Peak Signal to Noise Ratio), Índice de Similaridade Estrutural (SSIM - Structural Similarity Index) e Medição de Qualidade de Vídeo (VQM - Video Quality Metric). Com a finalidade de mostrar o desempenho das métricas objetivas em relação às subjetivas são empregados os coeficientes de correlação, além do erro de predição e quadrático médio. Adicionalmente, é importante destacar que a partir dos resultados obtidos são estabelecidos intervalos de valores de variação de atraso para os quais a qualidade do vídeo é considerada aceitável ou não para o usuário final. Finalmente, obtém-se uma Base de Dados de vídeos com diferentes graus de degradação da qualidade e que pode ser utilizada em futuras pesquisas. Nowadays, there is a wide range of telecommunications services focused on the transmission of voice, video and data across complex networks, although, in many cases, the end user is not satisfied with an acceptable quality level. In this work it is assessed how the video streaming service over an IP network can be affected by adverse conditions on the network, such as packet delay variation (jitter). Results from objective and subjective video streaming assessments are shown and indicate that the video quality is directly affected by IP network degradation factors such as packet delay variation. Beyond that, it is also verified that scenes with great movement content are also more sensitive to packet delay variation. For experimental tests, a network emulation totally isolated is considered, for which different network conditions are parameterized. Then, to the transmission channel, different values of packet delay variation are configured and videos are assessed, using subjective metrics: Absolute Category Rating (ACR) and Degradation Category Rating (DCR), and objective metrics: Peak Signal to Noise Ratio (PSNR), Structural Similarity (SSIM) and Video Quality Metric (VQM). In order to show the performance of objective metrics in relation to subjective ones correlation coefficients are employed as well as the prediction error and the mean square error. Finally, it is important to note that, from the results obtained, it can be established a range of delay variation values in which the video quality is acceptable or not at the end user. Additionally, a Video Data Base is obtained with different degrees of quality degradation and which can be used for future researches.

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Bršel, Boris. "Porovnání objektivních a subjektivních metrik kvality videa pro Ultra HDTV videosekvence." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2016. http://www.nusl.cz/ntk/nusl-241052.

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Master's thesis deals with the assessment of quality of Ultra HDTV video sequences applying objective metrics. Thesis theoretically describes coding of selected codecs H.265/HEVC and VP9, objective video quality metrics and also subjective methods for assessment of the video sequences quality. Next chapter deals with the implementation of the H.265/HEVC and the VP9 codecs at selected video sequences in the raw format from which arises the test sequences database. Quality of these videos is measured afterwards by objective metrics and selected subjective method. These results are compared for the purpose of finding the most consistent correlations among objective metrics and subjective assessment.

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Bain, Jonathan. "Subjective-Objective-Subjective: The Science Of Propaganda." Master's thesis, Faculty of Law, 2020. http://hdl.handle.net/11427/32197.

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This thesis discusses the following: 1. That, while advertising practitioners employ various levels of scientific endeavour (particularly strategic insight development, but also research, demographic data collection, and other objective tools of the trade), its final output is ultimately nonscientific, i.e. subjective creative ideation. (In this way, advertising is not dissimilar to the classic ‘art' of propaganda.) 2. That, for reasons of business necessity, creative ego and a latent form of ‘inferiority complex' the advertising industry describes its work in presentations to more scientifically-orientated clients as a more scientific proposition. 3. That, in contrast, as evidenced by the physical production process of the advertising idea (post the client presentation) – as well as in industry texts, award ceremonies, and selected case studies – advertising practitioners effectively acknowledge the subjective nature of their work. 4. That further evidence of this scientific ‘terministic screen' (Burke 1950, pp. 26-27) is also revealed in the failure of some television commercials to profitably ‘connect' as intended with an audience – thus undermining claims to the objective approach that preceded these commercials. 5. That, possibly, as is implied in at least one ethnographic case study, not even clients are necessarily convinced by advertising science: the ‘screen' may be a two-way mirror. 6. That there is, more broadly, a constant dialectic between right-brained creativity and the left-brained business project. 7. That this tension is a microcosm of the capitalist enterprise, and, in an increasing number of present examples, is perversely reflected in the advertising industry's output as anti-capitalist brand messaging. 8. That it is possible to think of advertising as a sub-set of a more consumer-orientated ‘design'. 6 9. That, admittedly within limited confines of my research, there is a tantalising indication that, generally, advertising artefacts were historically more logos-led, are currently more pathos-led, and may in future benefit from a more ethos-led orientation.

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Begazo, Dante Coaquira. "Método de avaliação de qualidade de vídeo por otimização condicionada." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/3/3142/tde-09032018-152946/.

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Esta Tese propõe duas métricas objetivas para avaliar a percepção de qualidade de vídeos sujeitos a degradações de transmissão em uma rede de pacotes. A primeira métrica usa apenas o vídeo degradado, enquanto que a segunda usa os vídeos de referência e degradado. Esta última é uma métrica de referência completa (FR - Full Reference) chamada de QCM (Quadratic Combinational Metric) e a primeira é uma métrica sem referência (NR - No Reference) chamada de VQOM (Viewing Quality Objective Metric). Em particular, o procedimento de projeto é aplicado à degradação de variação de atraso de pacotes (PDV - Packet Delay Variation). A métrica NR é descrita por uma spline cúbica composta por dois polinômios cúbicos que se encontram suavemente num ponto chamado de nó. Para o projeto de ambas métricas, colhem-se opiniões de observadores a respeito das sequências de vídeo degradadas que compõem o conjunto. A função objetiva inclui o erro quadrático total entre as opiniões e suas estimativas paramétricas, ainda consideradas como expressões algébricas. Acrescentam-se à função objetiva três condições de igualdades de derivadas tomadas no nó, cuja posição é especificada dentro de uma grade fina de pontos entre o valor mínimo e o valor máximo do fator de degradação. Essas condições são afetadas por multiplicadores de Lagrange e adicionadas à função objetiva, obtendo-se o lagrangiano, que é minimizado pela determinação dos coeficientes subótimos dos polinômios em função de cada valor do nó na grade. Finalmente escolhe-se o valor do nó que produz o erro quadrático mínimo, determinando assim os valores finais para dos coeficientes do polinômio. Por outro lado, a métrica FR é uma combinação não-linear de duas métricas populares, a PSNR (Peak Signal-to-Noise Ratio) e a SSIM (Structural Similarity Index). Um polinômio completo de segundo grau de duas variáveis é usado para realizar a combinação, porque é sensível a ambas métricas constituintes, evitando o sobreajuste em decorrência do baixo grau. Na fase de treinamento, o conjunto de valores dos coeficientes do polinômio é determinado através da minimização do erro quadrático médio para as opiniões sobre a base de dados de treino. Ambas métricas, a VQOM e a QCM, são treinadas e validadas usando uma base de dados, e testadas com outra independente. Os resultados de teste são comparados com métricas NR e FR recentes através de coeficientes de correlação, obtendo-se resultados favoráveis para as métricas propostas. This dissertation proposes two objective metrics for estimating human perception of quality for video subject to transmission degradation over packet networks. The first metric just uses traffic data while the second one uses both the degraded and the reference video sequences. That is, the latter is a full reference (FR) metric called Quadratic Combinational Metric (QCM) and the former one is a no reference (NR) metric called Viewing Quality Objective Metric (VQOM). In particular, the design procedure is applied to packet delay variation (PDV) impairments, whose compensation or control is very important to maintain quality. The NR metric is described by a cubic spline composed of two cubic polynomials that meet smoothly at a point called a knot. As the first step in the design of either metric, the spectators score a training set of degraded video sequences. The objective function for designing the NR metric includes the total square error between the scores and their parametric estimates, still regarded as algebraic expressions. In addition, the objective function is augmented by the addition of three equality constraints for the derivatives at the knot, whose position is specified within a fine grid of points between the minimum value and the maximum value of the degradation factor. These constraints are affected by Lagrange multipliers and added to the objective function to obtain the Lagrangian, which is minimized by the suboptimal polynomial coefficients determined as a function of each knot in the grid. Finally, the knot value is selected that yields the minimum square error. By means of the selected knot value, the final values of the polynomial coefficients are determined. On the other hand, the FR metric is a nonlinear combination of two popular metrics, namely, the Peak Signal-to-Noise Ratio (PSNR) and the Structural Similarity Index (SSIM). A complete second-degree two-variable polynomial is used for the combination since it is sensitive to both constituent metrics while avoiding overfitting. In the training phase, the set of values for the coefficients of this polynomial is determined by minimizing the mean square error to the opinions over the training database. Both metrics, the VQOM and the QCM, are trained and validated using one database and tested with a different one. The test results are compared with recent NR and FR metrics by means of correlation coefficients, obtaining favorable results for the proposed metrics.

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Chen, David. "Subjective and objective vehicle handling behaviour." Thesis, University of Leeds, 1997. http://etheses.whiterose.ac.uk/627/.

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This thesis presents results from a research project seeking to correlate subjective and objective measures of automobile handling. An underlying goal of the work was to demonstrate how a relatively simple lumped parameter model, suitable for effective use at the early stages of vehicle design, could be used to predict both the objective responses and subjective feel of the car. The work associated with the project was centred around sixteen configurations of a prototype saloon car. Objective evaluation included ISO defined steady state, step input, and frequency response testing. Subjective assessments were conducted by eight trained test drivers who supplied feedback in the form of numerical ratings on a questionnaire covering various aspects of handling. Examination of the two sets of data highlighted aspects of handling for which driver ratings correlated with objective data. It was also possible to quantify the average effect each objective response parameter had on driver ratings and thus to identify responses which most strongly influence subjective ratings. In addition a lumped parameter model allowing for lateral, yaw and roll degrees of freedom was validated against the experimental data. This validation demonstrated that the model was capable of accurate steady state and transient predictions both in the linear and non-linear range. The work concludes with a brief discussion about how the validated model, combined with the knowledge gained from the correlation work, could be used by engineers to streamline the design and development process.

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Péchard, Stéphane. "Qualité d'usage en télévision haute définition : évaluations subjectives et métriques objectives." Phd thesis, Université de Nantes, 2008. http://tel.archives-ouvertes.fr/tel-00348586.

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La télévision haute définition (TVHD) est le nouveau système de diffusion sensé apporter une plus grande immersion de l'observateur dans l'action et une qualité d'usage supérieure à celle de la télévision standard (TVSD). Afin de remplir ces exigences, les diffuseurs ont besoin de techniques de mesure de qualité adaptées. Le premier objectif de cette thèse est de nous éclairer sur l'impact de la transition de la TVSD vers la TVHD sur la qualité visuelle. Le second est de proposer des métriques objectives de qualité adaptées à la TVHD. Nous avons tout d'abord étudié plusieurs aspects de la qualité visuelle dans ce contexte. Cela nous a notamment permis de sélectionner une méthodologie d'évaluation subjective de la qualité pour constituer une base de séquences dégradées par un codage H.264. Puis, nous avons proposé une méthodologie d'évaluation de l'impact d'un système dégradant sur la qualité visuelle. Elle est utilisée dans les trois critères objectifs de qualité présentés par la suite. Elle fournit au premier une analyse du contenu permettant de modéliser la qualité visuelle d'une séquence. Le second critère cumule des fonctions de gêne locales en une note de qualité globale grâce à des modèles validés par la méthodologie. Le dernier exploite la notion de tubes spatio-temporels introduits par la méthodologie. Des caractéristiques y sont mesurées pour les séquences de référence et dégradée. Le cumul des différences entre ces caractéristiques fournit une note de qualité finale. Alors que le second critère n'offre pas de résultats convaincants, les deux autres permettent une prédiction des notes subjectives plus performante que celle de deux critères connus de la littérature.

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Nabi, Ghulam Rasul. "Predictors of objective and subjective career success." Thesis, University of Central Lancashire, 1999. http://clok.uclan.ac.uk/20076/.

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The main aim of this research was to examine predictors of both objective (salary). and subjective (perceived) career success. Three sets of predictors were examined: (1) individual attributes, (2) organisational opportunity structures and (3) career strategies. It was expected that a different pattern of variables would predict objective and subjective career success. In addition, the mediating role of career strategies was examined. It was expected that individual attributes and opportunity structures would be positively related to the use of career strategies, and that these strategies would be positively related to career success. Cross-sectional survey methodology was employed to collect data from a sample of 723 full-time employees in administrative/ technical, academic and managerial posts at several British universities. According to expectations, a different pattern of variables was related to objective and subjective career success. The strongest predictors of objective career success were education, organisational size and extended work involvement. In contrast, the strongest predictors of subjective career success were internal labour market perceptions of structured career progression and employment security. Separate analyses by gender and occupational group revealed a similar difference in the profile of predictors of objective and subjective career success. Overall, the results suggested that the variables that related to objective career success were often not the same as those related to subjective career success. This was taken as support for the main theme of this research that objective and subjective career success, although related, are substantially distinct concepts. Contrary to expectation, however, the results provided limited support for the mediating role of career strategies in the relationship between individual attributes, organisational opportunity structures and career success (objective and subjective). Only individual attributes (education and work centrality) were positively related to the use of career strategies (extended work involvement, selfpromotion and networking), and these strategies in turn were positively related to objective or subjective career success. However, the mediating role of career strategies was weak, albeit statistically significant. A number of limitations, mainly regarding the cross-sectional nature of the study, are discussed. Educational and organisational implications of the findings are suggested. Finally, a two-dimensional model of career success is proposed, incorporating the findings of the present research with reference to the predictors of objective and subjective career success, together with suggestions for further research.

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Meit, Heather Anderson. "Objective and subjective personality characteristics of medical students." Morgantown, W. Va. : [West Virginia University Libraries], 2001. http://etd.wvu.edu/templates/showETD.cfm?recnum=1919.

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Thesis (Ph. D.)--West Virginia University, 2001. Title from document title page. Document formatted into pages; contains vi, 68 p. : ill. Includes abstract. Includes bibliographical references (p. 55-62).

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34

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.

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Cette thèse a été effectuée en collaboration avec le Laboratoire national de métrologie et d’essais(LNE) dans le cadre d’une convention CIFRE. Dans ce travail, nous cherchons à réaliser une métrique objective dédiée à l’évaluation des dispositifs de restitution d’images (les écrans). Pour répondre à cette problématique, nous avons développé un algorithme permettant d’estimer la qualité à partir des qualités du moniteur et celles du Système visuel humain (SVH). L’algorithme développé se décompose en trois blocs. Le premier bloc prend en compte les caractéristiques d’un moniteur (fonction de transfert, gamut) pour modifier une image (envoyée à un moniteur par un dispositif numérique) en une image physique (affichée par le moniteur). Le deuxième bloc de l’algorithme modélise la transformation de l’image physique en une image perceptuelle. Cette modélisation implique la connaissance des principes de fonctionnement du système visuel humain, en particulier le codage d’une information couleur, mais aussi les attributs perceptuels intervenant dans le jugement de la qualité d’une image numérique couleur. Le troisième et dernier bloc a été développé afin d’attribuer une note de qualité à cette image perceptuelle. Une étude subjective de la qualité de cinq différents écrans LCD, faisant intervenir trente participants et conduite sur la base de six critères d’analyse, a été réalisée. Elle a permis de montrer que la teinte, la saturation et le contraste sont les facteurs prépondérants pour juger la qualité des écrans. La métrique développée à partir de ces constatations présente une corrélation satisfaisante avec les données issues de l’évaluation subjective, montrant ainsi sa proximité avec un jugement humain. Cette métrique a également été testée dans le cadre de la problématique de compression JPEG et JPEG2000 où elle s’est montrée également performante. Parmi les perspectives de ce travail, nous pouvons citer l’extension de l’étude à d’autres technologies d’écrans ainsi que la définition de bornes pour les scores de la métrique This 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

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BEKKAT, NACHIDA. "Critere objectif de qualite subjective d'images monochromes. Conception du modele et validation experimentale." Nantes, 1999. http://www.theses.fr/1999NANT2101.

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La conception de criteres objectifs d'evaluation de la qualite perceptuelle des images suscite un grand interet pour l'optimisation des systemes de traitement d'images. Les travaux de cette these s'inscrivent dans ce contexte. Un critere objectif de qualite doit fournir des mesures de qualite en forte correspondance avec celles fournies par des observateurs. Une modelisation des principales proprietes du systeme visuel humain (svh) doit donc etre etablie et prise en compte dans la conception d'un critere. C'est la demarche utilisee dans cette these. Nous avons concu, developpe et valide un critere objectif de qualite qui se decompose fonctionnellement en trois ensembles. Le premier correspond a une representation perceptuelle des images : un ensemble de 17 sous-bandes selectives en frequences spatiales a la fois en radial et en angulaire, ont ete utilisees pour modeliser les parties peripheriques du svh. Le second elabore la fonction d'adaptation des seuils de perception due a l'effet de masquage. Les seuils de visibilite de degradations sont mesures au niveau de chaque canal seul, puis en presence de signaux masquants issus d'autres canaux. Un modele de masquage tenant compte des caracteristiques frequentielles du signal et de la distribution de l'energie a travers les differents canaux est construit. L'etude de la perception des erreurs au-dela des seuils de visibilite a abouti a la determination d'une grandeur definissant la resolution de la perception des erreurs. Le dernier correspond aux cumuls des degradations et comprend deux etapes. La premiere fusionne les erreurs perceptuelles localisees, issues des differentes sous-bandes, en une grandeur unique restant localisee. La seconde effectue un cumul spatial de ces sites en une mesure unique par un modele parametrique de type probabiliste et non lineaire. Les parametres du modele sont optimises pour augmenter la correspondance entre la note objective et la moyenne des notes subjectives.

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Su, He Zhicheng Xuxin. "Links between Subjective Assessments and Objective Metrics for Steering." Thesis, KTH, Fordonsdynamik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101925.

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The characteristics of vehicle steering perception are decisive factors concerning vehicle safety and overall pleasure behind the wheel. It is a challenge for vehicle manufacturers to achieve these features and qualities, because usually vehicle tuning almost only relies on subjective evaluation of test drivers, which is costly and time consuming. In order to optimize suspension design and develop a tool that can be used to evaluate steering with objective metrics instead of subjective assessment, links between them must be confirmed. In this master thesis, both objective and subjective testing data of over 20 vehicles across four different segments are introduced in linear and nonlinear analysis. Linear regression analysis is applied to investigate simply positive or negative correlation between a pair of subjective-objective parameters. However, even if certain linear correlations are obtained, it is still hard to define the optimal value for objective metrics. Considering that the general shape of a correlation function can reveal which objective range give higher subjective rating, it is possible to define these preferred ranges with Neural Network (NN). The best data available is adopted from three drivers who tested 15 sedans, and some interesting results are found. The initial results demonstrate that NN is a powerful tool to uncover and graphically illustrate the links between objective metrics and subjective assessments, i.e., the specific range leading to better steering feel. Given a larger sample size, more reliable and optimal links can be defined by following the same method. These confirmed links would enable vehicle dynamics engineers to more effectively develop new vehicles with nearly perfect steering feel.

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Perry, Darren. "Relationship between objective impairment, subjective psychological factors and PCS." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.397568.

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Williams, Nicola Kim. "Objective predictors of subjective aesthetic ratings of web pages." Thesis, Keele University, 2015. http://eprints.keele.ac.uk/2324/.

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This research is concerned with the effect of visual stimulus on decision-‐making and opinions, what visual aspects of a page affect very early impressions of web sites, and how this relates to computational methods of prediction and evaluation of web pages. The aim of this study was to discover whether there are identifiable visual attributes of web pages that can be used to predict subjective opinions. This was explored through three separate studies. These consisted of two correlational studies and a categorisation task. Participants were gained through convenience and snowball sampling, and the materials reviewed were two distinct sets of web pages. Cards sorts, laddering and an online data collection tool were used to gather the information. Both qualitative and quantitative analysis was used to explore the information. The visual attributes found to correlate with subjective opinions were inconsistent across the two correlational studies. Study One had a number of limitations that may have contributed to this inconsistency. Concrete findings were that levels of encouragement and discouragement influenced by web pages are on two distinct scales, as, although there is a negative correlation between them, a large number of pages were rated poorly on both scales. The similarity between the card sort and questionnaire results had consistent findings for predictors of low-‐rated web pages. The findings from the cards sorts also show that users are able to make preference judgements of web pages without being able to understand the content. An application of the findings regarding prediction of low-‐rated pages would be to create web design optimisation system, enabling web pages to be reviewed computationally. Although this should never replace user testing, it may provide an economical alternative during the early stages of design.

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Statham, Andrew. "Subjective and objective assessment of tennis racket performance play." Thesis, Loughborough University, 2007. https://dspace.lboro.ac.uk/2134/4080.

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Assessment of wielded implement performance is important to a variety of human endeavours and often critical to success in a sports context, particularly so in the game of tennis. Tennis racket design and manufacture is a multimillion business involving 10 major international companies. Tennis participation is currently estimated at around 60 million individuals worldwide. Thus the importance of optimum racket performance to maximise competitive advantage and minimise the risks of injury is clear. This thesis presents work to enable advances in tennis racket performance with respect to player feel perception, measurement of physical phenomena and the correlation of these aspects within real play contexts. To investigate feel perception a methodology was adapted from the existing literature. Interview testing was conducted to elicit a comprehensive range of tennis specific vocabulary. The end goal was to create a perception relationship map or 'feel map'. The inductive analysis was used to link all the related clustered themes identified from the vocabulary to sub and base themes describing the relationship. Further analysis introduced higher level general dimensions that unified common base themes. The resulting feel maps were created from both English and German sample groups, with a view to subsequent comparison. To complete the map and broaden its application a wide scale questionnaire was distributed to a tennis playing population. The responses provided data indicating percentile use of selected vocabulary within the tennis community and the relative importance players associate with assorted perception groups. Visual representations of the data were introduced to the map for quick and easy use and an associated lexicon compiled to provide a reference for more detailed information. The feel maps and lexicon provide users with a versatile tool in the form of a 'perception relationship model'. The map itself can act as an overall research guide for future work in the field. The addition of percentile use and relative importance data mean the map can be used to create more informed and subtle player test questionnaires or as a design aid, with interdependency links indicating which additional factors should be considered or exploited for their influence on the characteristic areas in question. Interestingly the general dimensions of highest relative importance were sound and grip respectively. This may be due to the basic level of interaction between player and racket which ultimately has to be perceived either through the grip or from the sound. A perception test questionnaire was also created with the use of the feel map and later used to study the correlation between objective and subjective measures. To best attain objective measures from the racket an innovative instrumentation system was created. Two alternative systems were designed and tested, the first based on wired instrumentation and data capture the second based on wireless technologies as these became available. Both systems were required to take measures of grip pressure and acceleration with 6 degrees of freedom. The first system utilised uniaxial accelerometers mounted on an aluminium bracket, and a triaxial accelerometer inserted inside the butt of the racket arranged to allow measurement and calculation of acceleration from the required 6 degrees of freedom. The system could be adapted to include either TekScan multi-cell full grip coverage force measurement, or 2 single point higher sample rate single cell grip force sensors. All data was fed via 15 m of cable to data acquisition systems. This restricted the participants' freedom of movement and encumbered the racket and thus the systems application, making it unsuitable for extensive perception or fatigue testing. The second system utilised a compact data logger with an integrated on board tri-axial accelerometer small enough to be mounted within the racket handle. A revised mount overcame the need for the aluminium throat bracket, moving the uniaxial accelerometers into a bulbous addition to the butt of the racket. The system was capable of capturing 8 channels simultaneously which allowed for the 6 accelerometers and two single cell grip force sensors to be located under the grip. The system was more difficult to adapt and maintain than the wired system, but improved freedom and reduced added weight to the racket made the system far more suitable for the planned perception and fatigue testing. Fatigue testing conducted with the wireless device investigated the effect of full body fatigue on players' performance by monitoring the resultant effects in the racket. The protocol was based on the multistage fitness test, designed to progressively increase in difficulty until volitional fatigue. Heart rate data indicated that the protocol was successful in fatiguing the participants to a point at or near their VO2max. Unfortunately, with the wireless system in its early stages of development, the device failed mid way through testing. The limited data set that was collected indicated that technique was affected by fatigue. Further research is required to confirm this finding and to make comparisons between racket types during the fatiguing process. The wireless device was adapted to make it more durable and reliable before the planned perception testing was conducted. A protocol was developed to investigate the affect of changing racket moment of inertia on player perception and physical measures. The test questionnaire developed from the feel map was used to evaluate player perception ratings of various elements of racket feel, and the wireless instrumentation system was used as part of methodology designed to compile a set of comparable physical data. A detailed analysis of the results revealed that there was some evidence of correlation between the perceptions of power, balance, flexibility and control and the moment of inertia of the racket. In a design optimisation context, however, more definitive correlations would be more useful. These would be expected to be found with future testing utilising a wider range of racket properties. The research proves to a large extent the original hypothesis that through the use of non invasive instrumentation and improved player perception elicitation techniques it is possible to substantially and usefully improve the objective and subjective assessment of tennis racket performance in play to enable investigation of better design characteristics and fatigue related injury phenomena.

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Vonstad, Elise Klæbo. "Exergaming for Elderly: Subjective Experiences and Objective Movement Characteristics." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for nevromedisin, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25610.

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Background: It is important for elderly to stay healthy and independent for as long as possible, and falls are a major cause for loss of independence. Physical activity aimed at improving balance that includes large movements and cognitive tasks has been shown to decrease fall risk. Using exergames as a training tool has increased in recent years, but the actual movements elicited by such exergames have yet to be investigated objectively. Aim: To investigate usability and enjoyment and provide objective quantification of movement size elicited by two exergames. Methods: Twenty healthy elderly (mean age 74.4, range 65-90) played two exergames, The Mole (SilverFit) and LightRace (YourShape: Fitness Evolved) at easy and medium level, with five trials of one minute at each level. Data on perceived exertion (BORG), enjoyment and system usability (SUS) was collected.. Movements were captured using OQUS Motion Capture System, with passive reflexive markers attached to the base of the 1st toe, heel and lumbar area of the back. Movement size was expressed as Interquartile range (IQR) of feet and trunk in all three directions, and as horizontal area covered by the lumbar and toe markers. Correlational analyses were performed to investigate relationships between game scores, BORG-scores, SUS-scores, IQR and area coverage. Repeated measures ANOVAs were used to analyze effects of game, level, and trial. Results: Both games scored high on usability, and the elderly perceived the games as enjoyable, relevant as physical activity, and not very exhausting. Game scores increased across trials and decreased from easy to medium levels. Nevertheless, participants preferred the medium over the easy levels because of the increased cognitive challenge. IQR and area in the feet exceeded those in the trunk, especially in the medio-lateral direction. There were no significant correlations between game score and movement variables. Discussion: The positive attitude from the participants is promising for future implementation of exergames into fall preventive exercises. However, the lack of correlations between game scores and movement variables indicate that although these exergames do not reward players for "cheating" movements; they have room for improvement concerning rewarding desired movements. Keywords: older adults, exergames, movement characteristics, stepping.

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Freeman, Jonathan. "Subjective and objective approaches to the assessment of presence." Thesis, University of Essex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.298879.

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Witherwax, Renee Ann. "The subjective made manifest through interpretation of the objective." The Ohio State University, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=osu1314633976.

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STEPINSKI, JOY DIANA. "OBJECTIVE AND SUBJECTIVE MEASUREMENTS OF NORMAL AND OVER HYDRATION." University of Cincinnati / OhioLINK, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=ucin990804483.

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Bordel, Stéphanie. "Les dimensions objective et subjective du jugement de responsabilité." Rennes 2, 2002. http://www.theses.fr/2002REN20038.

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La @responsabilité apparaît comme une notion difficile à saisir. En effet, cette notion, qui appartient à la fois au langage ordinaire et au langage juridique, présente un caractère polysémique. Cependant, au-delà des divergences et des contradictions, il est possible, en s'appuyant notamment sur l'analyse sociologique de Fauconnet (1920) et les travaux de Piaget (1932) de distinguer deux types de responsabilité : la responsabilité objective et la responsabilité subjective. Ainsi, définir la responsabilité d'une personne reviendrait, d'une part, à chercher son rôle causal dans la production de l'évènement observé, c'est-à-dire à attribuer la causalité, il s'agit de la respondabilité objective, et d'autre part à prendre en compte des aspects plus téléologiques comme l'intentionnalité ou les raisons, il s'agit de la responsabilité subjective. . Cette proposition théorique a fait l'objet d'une validation empirique. Quatre séries d'études ont permis de mettre en évidence que la responsabilité peut effectivement être définie comme renvoyant à ces deux éléments, mais qu'ils sont indissociables l'un de l'autre. En effet, la responsabilité évoque toujours la responsabilité objective et la responsabilité subjective, et ce, quelle que soit l'information donnée aux sujets. Par ailleurs, il apparaît que les sujets, issus de sociétés ayant des droits différents, n'accordent pas une place identique à la responsabilité objective et à la responsabilité subjective The @responsibility appears like a difficult notion to understand. In fact, this word is part, at the same time, of ordinary language and juridcal language, it has a polysemic character. Far from those differences and contradictions, however, basing on the sociological analysis of Fauconnet (1920) and Piaget's work (1932), it is possible to distinguish two types of responsibility : objective responsibility and subjective responsibility. In this way, to define responsibility of a person would be, on one hand to search his causal role in the facts that are observed. This means doing causal attribution, it is the objective responsibility. On the other hand, it would be the research of teleological aspects like intentionnality or reasons, it is the subjective responsibility. This theoretical proposition forms the subject of an empirical validation. Four series of studies have shown that responsibility can in the facts be defined by those two components but that there are indissociable. Responsibility always recall to both objective responsibility and subjective responsibility whatever informations are given to the subjects. In other respects, it appears that the subjects, all coming from different societies with different laws, don't give the same place to objective responsibility and subjective responsibility

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Ash, Howard Alan Simon. "Correlation of subjective and objective handling of vehicle behaviour." Thesis, University of Leeds, 2002. http://etheses.whiterose.ac.uk/609/.

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This thesis presents the results of a research project which sought to find links between driver subjective ratings and objective measures of vehicle handling. The experimental data used in this project has been made available from a previous research project. The experimental data was collected using a prototype vehicle which was used in 16 different configurations. Objective data was collected based around the ISO defined steady state, step input, and frequency response tests. Subjective assessments were collected from eight trained test drivers using a numerical rating scale to a questionnaire covering various aspects of vehicle handling. Analysis of the subjective assessments has been done to identify any shortcomings that may affect any subsequent analysis. From the literature review, an approach that claims to relate four simple objective metrics to subjective measures of vehicle handling has been developed in two new ways. Firstly, the proposal was tested [1] with the large amount of subjective data available to see if good levels of correlation could be found between the proposed metrics and driver subjective ratings to specific handling questions. Secondly, the method was extended to include further simple metrics to try and improve links between the subjective and objective data [2]. Non-linear relationships in the correlation of subjective vs. objective data have been investigated for the first time [3] using non-linear genetic algorithms, which, in addition have not previously been used to correlate driver subjective ratings with objective measures that describe vehicle handling. From the results, it has been possible to specify ranges of preferred values of objective metrics in order to produce a subjectively satisfying vehicle. Finally, the work discusses how the results obtained can be used by engineers to aid the vehicle design and development process.

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Balderas, Gustavo. "Objective Versus Subjective Discipline Referrals in a School District." Thesis, University of Oregon, 2015. http://hdl.handle.net/1794/18722.

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Seven percent of all students are excluded from school every year across the United States for violating school policies and procedures. Exclusion from school causes a number of problems for students such as higher dropout rates, grade retention, more of a likelihood of not graduating from high school, and a widening of the achievement gap. However, the literature review reveals a lack of exclusion research specific to Hispanic students. Therefore, this research study investigated the level of disciplinary referrals leading to student suspensions during the 2013-2014 school year in a southern California school district of 9223 students with a student demographic composed of 39% free-and-reduced meals, 24% English language learners, and 36% Hispanic. The research study analyzed not just referrals but differences between subjective versus objective referrals for Hispanic and White students. Risk ratio results indicated that Hispanic students were more likely to receive referrals that resulted in suspensions from school at two-and-one-half times the rate compared to their White peers for both subjective (RR = 2.572) and objective (RR = 2.600) referrals. While there was no difference, p = .308, between referrals labeled as subjective versus objective, Hispanic students were significantly more likely to receive objective (p = .017) and subjective (p = .041) disciplinary referrals that resulted in suspensions compared to their White peers. The most significant factors that predicted overall student disciplinary referrals were English language learner status and free and reduced meals. In particular, English language status accounted for 60% of all referrals leading to a student suspension. Oppositely, factors that had the least predicted referral infractions were talented and gifted status, parent education level, and special education status. Results from this study provided school district staff with information that helped to revise district policy and procedures regarding the use of the suspension as an enforcement tool in student discipline, with particular focus on subjective versus objective referrals that could lead to student suspension. Implications of this research are discussed in relation to practice, procedures, and policies.

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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.

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Guéguin, Marie. "Evaluation objective de la qualité vocale en contexte de conversation." Phd thesis, Université Rennes 1, 2006. http://tel.archives-ouvertes.fr/tel-00132550.

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La qualité vocale des systèmes de télécommunications est évaluée par les opérateurs pour satisfaire leurs usagers. Les méthodes subjectives permettent de connaître le jugement humain mais sont coûteuses : les méthodes objectives représentent une alternative. Un modèle objectif est proposé pour évaluer la qualité en contexte de conversation à partir des qualités d'écoute, de locution et d'interaction. Il est divisé en deux parties : la partie intégration combine les notes de qualité d'écoute, de locution et d'interaction pour estimer une note de qualité de conversation et la partie mesure fournit les notes objectives de qualité à la partie intégration en se basant sur les modèles existants de qualité vocale dans les différents contextes. Quatre tests subjectifs étudiant différentes dégradations de la qualité de conversation sont utilisés pour construire et valider la partie intégration du modèle. Les performances du modèle sont vérifiées en l'appliquant à des signaux réels.

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Bednarz, Robin. "Analýza kvality obrazu v digitálních televizních systémech." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-217810.

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Diploma thesis deals with the analysis of quality in digital television systems and contains theoretical description of subjective and objective assessment of quality picture methods. The thesis contains short-term and long-term analysis of quality picture of terrestrial television DVB-T. Measurements and experimentations were carried out with the help of Rohde&Schwarz DVQ analyzer of picture quality and software MPEG-2 Quality Monitor and MPEG-2 Elementary stream analyzer.

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Skildheim, Kim Daniel. "Subjective and Objective Crosstalk Assessment Methodologies for Auto-stereoscopic Displays." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for elektronikk og telekommunikasjon, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18913.

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Stereoscopic perception is achievable when the observer sees a scene from a slightly different angle. Auto-stereoscopic displays utilize several separate views to achieve this without using any special glasses. Crosstalk is an undesired effect of separating views. It is one of the most annoying artefacts occurring in an auto-stereoscopic display. This experiment has two parts. The first part proposes a subjective assessment methodology for characterizing crosstalk in an auto-stereoscopic display, without restriction of subjects viewing behaviour. The intention was to create an inexpensive method. The measurement was performed by using a Kinect prime sensor as a head tracking system combined with subjective score evaluation to get a data plot of the perceived crosstalk. The crosstalk varies in line with image content, disparity and viewing position. The result is a data plot that approaches a periodically pattern, which is consistent with the characteristics of an auto-stereoscopic display. The result is not perfect since there are many sources of errors occurring. These errors can be improved with better head tracking, an improved movement system, post processing of data, more data and removal of outliers.The second part proposes methods for extracting subjective values based on interpolated plots and creating objective crosstalk influenced pictures which correlate with the subjective data. The best extraction method was to combine an adapted sine regression curve with a linear interpolation. This interpolation followed the subjective values in a parallel slice plot at 3.592 m from the screen. The interpolation was adapted to fit a derived model as best as possible to achieve a good correlation. Objective crosstalk pictures were created, where the amount of crosstalk was determined by the neighbouring view that influenced the current view the most. The correlation was based on the relationship between the SSIM value from the created crosstalk picture and the extracted subjective value. The total correlation of the pictures together were 0,8249, where the picture with the highest correlation had 0,9561. This method is quite good for pictures that have a maximum disparity grade below 38 pixels. The overall result is good and it is also a measure of quality for the subjective test. This result can be improved by increasing the complexity of how the objective crosstalk pictures are created by adding more views into account or try another method to create crosstalk. Improved extraction of subjective values will also be beneficial in terms of improving the correlation even more.

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Dissertations / Theses on the topic 'Objective and subjective quality'

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