Dissertations / Theses on the topic 'Limitations of logic'

This thesis is about dialetheism and the problem of revenge. More broadly, it is about truth and what the logical paradoxes tell us about the logical behaviour of truth. One of the driving forces behind the contemporary study of truth and paradox is the problem of revenge: that many, perhaps all, available theories of truth, give rise to further paradoxes, invoking central notions of those theories, which demonstrate that the theory cannot express those notions. This sort of expressive limitation, especially if it involves the very notion invoked to diagnose what goes wrong in paradoxical sentences, would normally be thought a decisive point against a given theory of the paradoxes, were it not for the fact that the problem is so pervasive that every currently available theory has, at some point, been argued to suffer from it. Dialetheism, the view that some contradictions are true, has often been thought to be the only view which has a reasonable chance of avoiding the problem. Indeed, the surge of interest in the view since the first publication of Priest’s In Contradiction, in 1987, defending dialetheism, is probably due in large part to the seeming immunity to the revenge problem that Priest’s view possesses. Its virtue, in respect of revenge, is that its ability to accept, without collapse into incoherence, contradictions, allows it to accept any further revenge paradoxes as merely giving more sound arguments for dialetheia (true contradictions). This thesis argues that this appearance of revenge-immunity is mistaken. Dialetheism, too, has its revenge problems. The seeming virtue of dialetheism, that it can accept the contradictions generated by revenge paradoxes without incoherence, also has its drawbacks. This is because dialetheists are not only able, but compelled to accept the contradictions arising from the semantic paradoxes. This means that contradictions can arise in certain areas where they are undesirable. In particular, there are notions which seem to require consistency in order to be expressible. If we can demonstrate, using revenge paradoxes, that, on dialetheism, predicates putatively representing these notions would have to behave inconsistently, then we can demonstrate that dialetheists cannot express the notions. There are many ways one might wish to carve up the different varieties of dialetheism available. I have separated the view into two broad kinds: metatheoretically paraconsistent dialetheism, on the one hand, and metatheoretically consistent dialetheism, on the other. This distinction decides to which variety of revenge problem the version of dialetheism in question is subject. I take each in turn, and argue that they are each subject to expressive limitations brought about by revenge paradox.

The motivation for this thesis is rooted in the problems arising from the lack of a single theoretical framework within which to assimilate different analytical methods; whether they are applied to an individual work, compositions embracing an underlying common practice or to the study of stylistically remote pieces. By devising a series of logical axioms and definitions, collectively referred to as a metatheory and situating them - as an expression of the neutral level originally proposed by Jean Molino - in the context of the semiological tripartition, it is found that the metatheory can be used to construct aspects of existing music theories. The precise extent to which a specific theory of music can be derived from the metatheory is not considered, but the many examples used to illustrate the application of metatheoretical logic to music analysis clearly demonstrate that meaning can only be ascribed to the structural configurations so determined if the poietic and esthesic dimensions of the tripartition are invoked as a means of distinguishing the actual from the logically possible. It is in this sense that logic is found to be limited. Two important consequences follow from this conceptual framework. Firstly, the involvement of the poietic and esthesic dimensions in the final analysis potentially enables many diverse theories to be derived from the metatheory, thereby preserving the important differences that exist between analytical methods. Secondly, the whole notion of a text-centred theory of music is challenged since the importance of the poietic and esthesic dimensions to the provision of meaning is such that these dimensions can theoretically overwhelm the configurations established within the text by the application of logic.

For all the successes of the two edifices of modern physics, quantum theory and Einstein's relativity, a fundamental description of the Universe as a whole -- a theory that informs as to the true nature of reality -- has continued to elude science. This thesis describes the development and evolution of a new paradigm called Process Physics, a radical information-theoretic modelling of reality. It is argued that the failure of the extant approaches in physics is the direct consequence of limitations stemming from the mathematization, language and methodology of theoretical physics: the limitations of the postulated background spatial concepts and geometric modelling of time, the limitations of quantum theory in its failure to account for the measurement process and classicality; and the limitations of formal systems. In contrast, Process Physics utilizes the limitations of logic first identified by Godel and asserts the priority of process and relational endophysics, realized via a stochastic, autopoietic bootstrap system whose properties emerge a posteriori rather than being assumed a priori. The work is arranged in two parts. Part I discusses the historical, philosophical, and metaphysical foundations of physics to consider how the prevailing views in modern physics arose and what this revealed and contributed to the development of Process Physics. Part II describes the fundamentals of the new theory and its implementation, and demonstrates the viability of looking outside the current paradigms by showing that Process Physics yields unified emergent phenomena that permit an understanding of fundamental processes and penultimately motivate both quantum theory and relativity as relevant higher-level descriptors within their respective domains.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1994.
Includes bibliographical references (p. 99-102).
by Jonathan William Babb.
M.S.

Malgré leur fort développement en assainissement domestique urbain, les bioréacteurs à membranes (BaM) pâtissent de phénomènes de colmatage, induisant des coûts énergétiques et de maintenance importants. L’aération séquencée des membranes par des grosses bulles est l’une des stratégies pour limiter le colmatage ; son impact a fait l’objet de plusieurs études mais reste globalement mal compris, notamment du fait de la complexité de ces systèmes, multiphasiques et opaques. L’hydrodynamique des réacteurs reste mal caractérisée en présence de boues. Pour apporter des éléments de compréhension aux mécanismes de limitation du colmatage par injection d’air, un pilote de filtration membranaire semi-industriel (2 m3, 3 sous modules fibres creuses Puron®) a été conçu, dimensionné et installé sur l’unité de traitement des jus (TDJ) de la station d’épuration Seine Aval (SIAAP), afin d’être alimenté en boues biologiques dans des conditions réelles de fonctionnement. Le suivi des paramètres opératoires du pilote et de ses performances de filtration sur une période de 5 mois avait un double objectif : (i) mieux caractériser la dispersion du gaz pour différentes conditions de fonctionnement (paramètres de l’aération, concentration en boues de l’alimentation), (ii) hiérarchiser les facteurs qui limitent le colmatage des membranes. Il s’agit in fine de proposer des stratégies d’aération adaptées et efficaces pour limiter le colmatage. Afin de caractériser la dispersion du gaz dans le réacteur, une méthodologie innovante basée sur la tomographie de résistivité électrique (ERT) a été adaptée au pilote. Les conditions d’utilisation de l’ERT (nombre d’électrodes de mesure, séquence de quadripôles) ont été sélectionnées à travers une étude numérique, de même que les paramètres d’inversion nécessaires pour reconstituer la cartographie des résistivités à partir des mesures expérimentales. Cette étude numérique poussée, réalisée sous COMSOL, a permis de conclure à l’intérêt de la méthode pour représenter la distribution des phases dans la géométrie considérée. L’ERT a donc été appliquée au pilote alimenté en boues, pour différentes conditions d’aération. Le jeu de données de filtration a par ailleurs été analysé par logique floue, à l’aide du logiciel FisPro. Les arbres de décision obtenus, en analysant les résultats de manière globale et en les regroupant par conditions opératoires similaires, ont mis en évidence l’impact prépondérant des variables suivantes sur la dérive de perméabilité observée (comprise entre - 9 et 2 LMH/bar) : la différence de DCO entre le surnageant des boues et le perméat (DDCO) traduisant une phase colloïdale complexe, et la concentration en matières en suspension (MES), ayant toutes deux un impact négatif sur les performances de filtration. Une augmentation du débit d’air conduirait à une limitation de la dérive de perméabilité, sauf lorsque la variable DCO est élevée (> à 500 mg/L), cette hypothèse restant cependant à vérifier sur une base de données plus conséquente. Le modèle ainsi obtenu par logique floue permet de mieux simuler les évolutions de perméabilité que les modèles obtenus par régression linéaire multivariée (erreurs de 0,61 et de 0,70 respectivement), et ce malgré une incertitude relative importante sur la mesure de perméabilité (jusqu’à 16 %). Ces résultats sont cohérents avec la dispersion du gaz observée par ERT : son homogénéité dépend de la concentration en MES et du débit d’air injecté. A forte concentration en MES (6 – 10 g/L), des zones préférentielles de passage des bulles ont été observées, en particulier à faible débit d’air, expliquant ainsi un colmatage plus important. L’utilisation nouvelle dans ce contexte de ces techniques, ERT et logique floue, donne des résultats qui confortent l’intérêt d’adapter l’aération (débit, séquençage) aux caractéristiques des boues notamment leurs concentrations, et qui permettent d’envisager des stratégies de contrôle de ces paramètres

Active vehicle safety systems for road vehicles play an important role in accident prevention. In recent years, rapid developments have been observed in this area with advancing technology and electronic control systems. Active yaw control is one of these subjects, which aims to control the vehicle in case of any impending spinning or plowing during rapid and/or sharp maneuver. In addition to the development of these systems, integration and cooperation of these independent control mechanisms constitutes the current trend in active vehicle safety systems design. In this thesis, design methodology and simulation results of an active yaw control system for two axle road vehicles have been presented. Main objective of the yaw control system is to estimate the desired yaw behavior of the vehicle according to the demand of the driver and track this desired behavior accurately. The design procedure follows a progressive method, which first aims to design the yaw control scheme without regarding any other stability parameters, followed by the development of the designed control scheme via taking other stability parameters such vehicle sideslip angle into consideration. A two degree of freedom vehicle model (commonly known as &ldquo
Bicycle Model&rdquo
) is employed to model the desired vehicle behavior. The design of the controller is based on Fuzzy Logic Control, which has proved itself useful for complex nonlinear design problems. Afterwards, the proposed yaw controller has been modified in order to limit the vehicle sideslip angle as well. Integration of the designed active yaw control system with other safety systems such as Anti-Lock Braking System (ABS) and Traction Control System (TCS) is another subject of this study. A fuzzy logic based wheel slip controller has also been included in the study in order to integrate two different independent active systems to each other, which, in fact, is a general design approach for real life applications. This integration actually aims to initiate and develop the integration procedure of the active yaw control system with the (ABS). An eight degree of freedom detailed vehicle model with nonlinear tire model is utilized to represent the real vehicle in order to ensure the validity of the results. The simulation is held in MATLAB/Simulink environment, which has provided versatile design and simulation capabilities for this study. Wide-ranging simulations include various maneuvers with different road conditions have been performed in order to demonstrate the performance of the proposed controller.

Le vieillissement de la population s’accompagne de pathologies chroniques, productrices de dépendance, dont la principale cause est le déclin cognitif et la démence, empêchant un vieillissement en bonne santé. Les troubles visuels, fréquents dans la population âgée et insuffisamment pris en charge, pourraient représenter une piste pour la prévention de ces pathologies chroniques. L’objectif principal de cette thèse était d’analyser le retentissement des troubles visuels sur la perte d’autonomie et les troubles cognitifs du sujet âgé et d’évaluer dans quelle mesure l’amélioration de la vision des personnes âgées pourrait améliorer leur état de santé. Ces travaux ont été réalisés à partir des données de 9294 participants de l’étude des Trois-Cités (3C) et de 963 participants de l’étude ophtalmologique Aliénor, nichée dans la cohorte 3C. Ces cohortes comportent des données détaillées de cognition, de dépendance et de vision. Dans notre étude, nous avons estimé que 38,8% des personnes âgées avaient des erreurs de réfraction (myopie, astigmatisme, hypermétropie) mal ou non corrigées par des lentilles ou lunettes de vue. Une dépendance plus élevée a été retrouvée à partir d’une acuité visuelle de loin inférieure à 8/10ème et près de 1/5 de la dépendance pourrait être évitée par des lentilles ou lunettes de vue adaptées. Les troubles visuels ont été associés à un risque augmenté de démence au cours de 12 ans de suivi, avec un risque plus élevé chez les personnes présentant de façon conjointe des troubles dépressifs. En revanche, aucune association longitudinale n’a été retrouvée avec le déclin cognitif. Ces travaux apportent des arguments pour justifier d'une meilleure prise en charge des troubles visuels en prévention de la dépendance ; toutefois des études complémentaires semblent nécessaires pour conforter l'impact des troubles visuels sur la démence
With the ageing of the population there is an increase of chronic pathologies, leading to functional limitations. Cognitive decline and dementia are the main causes of these limitations, preventing healthy ageing. Visual impairment, frequent in the elderly population and insufficiently managed, could represent a pathway for the prevention of these pathologies. The main objective of this work was to analyze the impact of visual impairment on activity limitations and cognitive impairment and to evaluate to what extent the improvement of vision could improve cognitive and functional health. This work was based on the analysis of 9294 participants from the Three City (3C) cohort and 963 participants from the Alienor ophthalmological study, nested in the 3C study. Detailed data on cognition, activity limitations and vision are available in these cohorts. In our study, we estimated that 38.8% of older adults had refractive errors (myopia, astigmatism, and hyperopia) which were poorly or not corrected by lenses or glasses. An effect of visual impairment on activity limitations has been found from a visual acuity less than 20/25 and nearly 1/5 of limitations could be avoided by best-achieved optical correction. Visual impairment was also associated with an increased risk of dementia over a 12-year follow-up period, with a higher risk in participants with both visual impairment and depressive symptoms. Nevertheless, no longitudinal associations were found with cognitive decline. This thesis provides supplementary arguments to promote a better management of visual impairment in prevention of functional limitations; however, further studies are needed to study the impact of visual impairment on cognitive decline and dementia

In dieser Arbeit wird ein simultanes Quell-, Ziel-, Verkehrsmittel- und Routenwahlmodell (Modell EVA-U) entwickelt, welches ein stochastisches Nutzergleichgewicht erreicht. Die Routenwahlmodelle der Verkehrsarten sind nicht mehr Teil der Umlegungsalgorithmen, sondern in das Nachfragemodell integriert. Dadurch ist eine konsistente Bewertung aller Alternativen (der Verkehrsarten) möglich. Das Simultanmodell EVA-U stellt eine Weiterentwicklung des Simultanmodells EVA von LOHSE dar. Das EVA-U-Modell ist den universalen Logit-Modellen zuzuordnen. Die Randsummenbedingungen der Verkehrsverteilung werden beachtet. Die Bewertung der Alternativen erfolgt mittels Generalisierter Kosten. Die Abhängigkeit von Routen wird berücksichtigt, ebenso die Tagesganglinie der Verkehrsnachfrage und die Fahrpläne des ÖV-Systems. Das Modell EVA-U erlaubt auch die Berücksichtigung von Routen intermodaler Verkehrsarten (z.B. P+R). Darüber hinaus ist die Integration eines Modells des ruhenden Verkehrs möglich
In this thesis a simultaneous Trip Generation-, Distribution-, Modal-Split and Route Choice Model (modell EVA-U) is elaborated. The model tends to reach a stochastic user equilibrium. The route choice algorithms are not longer part of an assignment procedure but part of the demand model. A consistent assessment of properties of all transport systems is possible. The simultaneous model EVA-U is an advancement of the EVA-Model by Lohse. The model EVA-U is to be assigned to the generalised logit-models. All matrix constrains are taken into account. The assessment is effected by generalised costs. The dependence of routes is taken into account. Moreover, the integration of day time and the schedules of private transport lines is possible. Furthermore, it is possible to integrate a model of parked cars and circuits of inter-modal traffic forms (park and ride) in the Model EVA-U

In dieser Arbeit wird ein simultanes Quell-, Ziel-, Verkehrsmittel- und Routenwahlmodell (Modell EVA-U) entwickelt, welches ein stochastisches Nutzergleichgewicht erreicht. Die Routenwahlmodelle der Verkehrsarten sind nicht mehr Teil der Umlegungsalgorithmen, sondern in das Nachfragemodell integriert. Dadurch ist eine konsistente Bewertung aller Alternativen (der Verkehrsarten) möglich. Das Simultanmodell EVA-U stellt eine Weiterentwicklung des Simultanmodells EVA von LOHSE dar. Das EVA-U-Modell ist den universalen Logit-Modellen zuzuordnen. Die Randsummenbedingungen der Verkehrsverteilung werden beachtet. Die Bewertung der Alternativen erfolgt mittels Generalisierter Kosten. Die Abhängigkeit von Routen wird berücksichtigt, ebenso die Tagesganglinie der Verkehrsnachfrage und die Fahrpläne des ÖV-Systems. Das Modell EVA-U erlaubt auch die Berücksichtigung von Routen intermodaler Verkehrsarten (z.B. P+R). Darüber hinaus ist die Integration eines Modells des ruhenden Verkehrs möglich.
In this thesis a simultaneous Trip Generation-, Distribution-, Modal-Split and Route Choice Model (modell EVA-U) is elaborated. The model tends to reach a stochastic user equilibrium. The route choice algorithms are not longer part of an assignment procedure but part of the demand model. A consistent assessment of properties of all transport systems is possible. The simultaneous model EVA-U is an advancement of the EVA-Model by Lohse. The model EVA-U is to be assigned to the generalised logit-models. All matrix constrains are taken into account. The assessment is effected by generalised costs. The dependence of routes is taken into account. Moreover, the integration of day time and the schedules of private transport lines is possible. Furthermore, it is possible to integrate a model of parked cars and circuits of inter-modal traffic forms (park and ride) in the Model EVA-U.

Until recent years, terahertz (THz) waves were an undiscovered, or most importantly, an unexploited area of electromagnetic spectrum. This was due to difficulties in generation and detection of THz waves. Recent advances in hardware technology have started to open up the field to new applications such as THz imaging. This non-destructive and non-contact imaging technique can penetrate through diverse materials such that internal structures, in some cases invisible to other imaging modalities, can be visualized. Today, there are variety of techniques available to generate and detect THz waves in both pulsed and continuous fashion in two different geometries; transition, and reflection modes. In this thesis continuous wave THz imaging was employed for higher spatial resolution. However, with any new technology comes its challenges; automated processing of THz images can be quite cumbersome. Low contrast and the presence of a widely unknown type of noise make the analysis of these images difficult. In this work, there is an attempt to detect defects in composite material via segmentation by using a Terahertz imaging system. According to our knowledge, this is the first time that this type of materials are being tested under Terahertz cameras to detect manufacturing defects in aerospace industry. In addition, segmentation accuracy of THz images have been investigated by using a phantom. Beyond the defect detection for composite materials, this can establish some general knowledge about Terahertz imaging, its capabilities and limitations. To be able to segment the THz images successfully, pre-processing techniques are inevitable. In this thesis, a variety of different image processing techniques, self-developed or available from literature, have been employed for image enhancement. These methods range from filtering to contrast adjustment to fusion of phase and amplitude images by using fuzzy set theory, to just name a few. The result of pre-procssing and segmentation methods demonstrates promising outcome for future work in this field.

The group work to which this individual reports hould be attached does not mention certain characteristics of the data that could be used for other research papers and for the bank. As such, this individual work develops the topics of limitations of the database used, the limitations of the type of work done in the Portuguese market, key characteristics of the variables used, and recommendations to the bank on further improvement of the model used and ,from the perspective of a consultant, on what the bank could improve internally.