In synaesthetic personification, personality traits and other human characteristics are attributed to linguistic sequences and objects. Such non-perceptual concurrents are different from those found in most frequently studied types of synaesthesia, in which the eliciting stimuli induce sensory experiences. Here, subjective reports from synaesthetes were analysed and the cognitive and neural mechanisms underlying personification were investigated. Specifically, the neural bases of personification were examined using functional MRI in order to establish whether brain regions implicated in social cognition are involved in implementing personification. Additional behavioural tests were used to determine whether personification of inanimate objects is automatic in synaesthesia. Subjective reports describing general characteristics of synaesthetic personification were collected using a semi-structured questionnaire. A Stroop-like paradigm was developed in order to examine the automaticity of object personification, similarly to the previous investigations. Synaesthetes were significantly slower in responding to incongruent than to congruent stimuli. This difference was not found in the control group. The functional neuroimaging investigations demonstrated that brain regions involved in synaesthetic personification of graphemes and objects partially overlap with brain areas activated in normal social cognition, including the temporo-parietal junction, precuneus and posterior cingulate cortex. Activations were observed in areas known to be correlated with mentalising, reflecting the social and affective character of concurrents described in subjective reports. Psychological factors linked with personification in previous studies were also assessed in personifiers, using empathy, mentalising and loneliness scales. Neither heightened empathy nor mentalising were found to be necessary for personification, but personifying synaesthetes in the study felt lonelier than the general population, and this was more pronounced in those who personified more. These results demonstrate that personification shares many defining characteristics with classical forms of synaesthesia. Ascribing humanlike characteristics to graphemes and objects is a spontaneous and automatic process, inducer-concurrent pairings are consistent over time and the phenomenological character of concurrents is reflected in functional neuroanatomy. Furthermore, the neuroimaging findings are consistent with the suggestions that synaesthetes have a lower threshold for activation brain regions implicated in self-projection and mentalising, which may facilitate the personification processes in synaesthesia.

Microsleeps and other lapses of responsiveness can have severe, or even fatal, consequences for people who must maintain high levels of attention on monotonous tasks for long periods of time, e.g., commercial vehicle drivers, pilots, and air-traffic controllers. This thesis describes a head-mounted system which is the first prototype in the process of creating a system that can detect (and possibly predict) these lapses in real time. The system consists of a wearable device which captures multiple physiological signals from the wearer and an extensible software framework for imple- menting signal processing algorithms. Proof-of-concept algorithms are implemented and used to demonstrate that the system can detect simulated microsleeps in real time. The device has three sensing modalities in order to get a better estimate of the user＇s cognitive state than by any one alone. Firstly, it has 16 channels of EEG (8 currently in use) captured by 24-bit ADCs sampling at 250 Hz. The EEG is acquired by custom-built dry electrodes consisting of spring-loaded, gold-plated pins. Secondly, the device has a miniature video camera mounted below one eye, providing 320 x 240 px greyscale video of the eye at 60 fps. The camera module includes infrared illumination so that it can operate in the dark. Thirdly, the device has a six-axis IMU to measure the orientation and movement of the head. These sensors are connected to a Gumstix computer-on-module which transmits the captured data to a remote computer via Wi-Fi. The device has a battery life of about 7.4 h. In addition to this hardware, software to receive and analyse data from the head-mounted device was developed. The software is built around a signal processing pipeline that has been designed to encapsulate a wide variety of signal processing algorithms; feature extractors calculate salient properties of the input data and a classifier fuses these features to determine the user＇s cognitive state. A plug-in system is provided which allows users to write their own signal processing algorithms and to experiment with different combinations of feature extractors and classifiers. Because of this flexible modular design, the system could also be used for applications other than lapse detection‒any application which monitors EEG, eye video, and head movement can be implemented by writing appropriate signal processing plug-ins, e.g., augmented cognition or passive BCIs. The software also provides the ability to configure the device＇s hardware, to save data to disk, and to monitor the system in real time. Plug-ins can be implemented in C++ or Python. A series of validation tests were carried out to confirm that the system operates as intended. Most of the measured parameters were within the expected ranges: EEG amplifier noise = 0.14 μVRMS input-referred, EEG pass band = DC to 47 Hz, camera focus = 2.4 lp/mm at 40 mm, and total latency < 100 ms. Some parameters were worse than expected but still sufficient for effective operation: EEG amplifier CMRR ≥ 82 dB, EEG cross-talk = -17.4 dB, and IMU sampling rate = 10 Hz. The contact impedance of the dry electrodes, measured to be several hundred kilohms, was too high to obtain clean EEG. Three small-scale experiments were done to test the performance of the device in operation on people. The first two demonstrated that the pupil localization algorithm produces PERCLOS values close to those from a manually-rated gold standard and is robust to changes in ambient light levels, iris colour, and the presence of glasses. The final experiment demonstrated that the system is capable of capturing all three physiological signals, transmitting them to the remote computer in real time, extracting features from each signal, and classifying simulated microsleeps from the extracted features. However, this test was successful only when using conventional wet EEG electrodes instead of the dry electrodes built into the device; it will be necessary to find replacement dry electrodes for the device to be useful. The device and associated software form a platform which other researchers can use to develop algorithms for lapse detection. This platform provides data capture hardware and abstracts away the low-level software details so that other researchers are free to focus solely on developing signal processing techniques. In this way, we hope to enable progress towards a practical real-time, real-world lapse detection system.

Digital Image Elasto Tomography (DIET) is a non-invasive elastographic breast cancer screening technology, relying on image-based measurement of surface vibrations induced on a breast by mechanical actuation. Knowledge of frequency response characteristics of a breast prior to imaging is critical to maximize the imaging signal and diagnostic capability of the system. A non-invasive image based modal analysis system that is designed to be able to robustly and rapidly identify resonant frequencies in soft tissue is presented in this thesis. A feasibility analysis reveals that three images per oscillation cycle are sufficient to capture the relative motion behavior at a given frequency. Moreover, the analysis suggests that 2D motion analysis is able to give an accurate estimation of the response at a particular frequency. Thus, a sweep over critical frequency ranges can be performed prior to imaging to determine critical imaging settings of the DIET system to maximize diagnositc performance. Based on feasibility simulations, a modal analysis system is presented that is based on the existing DIET digital imaging system. A frequency spectrum plot that comprises responses gathered from more than 30 different frequencies can be obtained in about 6 minutes. Preliminary results obtained from both phantom and human trials indicate that distinctive resonant frequencies can be obtained with the modal analysis system. Due to inhomogeneous properties of human breast tissues, different imaging location appear to pick up different resonances. However, there has been very limited clinical data for validating such behavior. Overall, a modal analysis system for soft tissue has been developed in this thesis. The system was first evaluated in simulation, then implemented in hardware and software, and finally successfully validated in silicone phantoms as well as human breasts.

This thesis work is based on the analysis of a fan blade attachment whereby a complete 3D model is presented by a partner company. The acceptability of a new design regarding the mechanical loads consisting of dividing the hub into two parts instead of using a solid hub is studied. From the model some critical parameters for the attachment of the blade with respect to the stresses are chosen such as the rotational speed, fillet size of the blade and the neck size of the blade. Parametric studies of these parameters are carried out in order to suggest the new design. Bearing in mind that a safety factor of 2 is the prerequisite, based on the analysis performed on ANSYS Workbench, it is suggested from the preliminary design that the axial fan can operate in two specific scenarios consisting of a rotational speed of 1771 rpm and a rotational speed of 1594 rpm. Using this set of parameters, a suggestion is drawn up on the blade fillet which will give lower stress. Blade fillet size of 30 to 35mm is recommended while a size of 45mm is recommended on the neck of the blade. A modal analysis is performed in order to find at what frequency will the model be vibrating and a lowest and critical frequency of 16.8 Hz is obtained. Finally, a fatigue analysis of some interesting areas is performed in order to determine the numbers of cycles before fatigue failure occur. It is recommended to use the rotational speed since these speeds have offered a High Cycle Fatigue results.

In concurrency theory—the branch of (theoretical) computer science that studies the logical and mathematical foundations of parallel computation—there are two main formal ways of modelling the behaviour of systems where multiple actions or events can happen independently and at the same time: either with interleaving or with partial order semantics. On the one hand, the interleaving semantics approach proposes to reduce concurrency to the nondeterministic, sequential computation of the events the system can perform independently. On the other hand, partial order semantics represent concurrency explicitly by means of an independence relation on the set of events that the system can execute in parallel; following this approach, the so-called ‘true concurrency’ approach, independence or concurrency is a primitive notion rather than a derived concept as in the interleaving framework. Using interleaving or partial order semantics is, however, more than a matter of taste. In fact, choosing one kind of semantics over the other can have important implications—both from theoretical and practical viewpoints—as making such a choice can raise different issues, some of which we investigate here. More specifically, this thesis studies concurrent systems with partial order semantics and focuses on their bisimulation and model-checking problems; the theories and techniques herein apply, in a uniform way, to different classes of Petri nets, event structures, and transition system with independence (TSI) models. Some results of this work are: a number of mu-calculi (in this case, fixpoint extensions of modal logic) that, in certain classes of systems, induce exactly the same identifications as some of the standard bisimulation equivalences used in concurrency. Secondly, the introduction of (infinite) higher-order logic games for bisimulation and for model-checking, where the players of the games are given (local) monadic second-order power on the sets of elements they are allowed to play. And, finally, the formalization of a new order-theoretic concurrent game model that provides a uniform approach to bisimulation and model-checking and bridges some mathematical concepts in order theory with the more operational world of games. In particular, we show that in all cases the logic games for bisimulation and model-checking developed in this thesis are sound and complete, and therefore, also determined—even when considering models of infinite state systems; moreover, these logic games are decidable in the finite case and underpin novel decision procedures for systems verification. Since the mu-calculi and (infinite) logic games studied here generalise well-known fixpoint modal logics as well as game-theoretic decision procedures for analysing concurrent systems with interleaving semantics, this thesis provides some of the groundwork for the design of a logic-based, game-theoretic framework for studying, in a uniform manner, several concurrent systems regardless of whether they have an interleaving or a partial order semantics.

Things could have been different, but could it also have been different what things there are? It is natural to think so, since I could have failed to be born, and it is natural to think that I would then not have been anything. But what about entities like propositions, properties and relations? Had I not been anything, would there have been the property of being me? In this thesis, I formally develop and assess views according to which it is both contingent what individuals there are and contingent what propositions, properties and relations there are. I end up rejecting these views, and conclude that even if it is contingent what individuals there are, it is necessary what propositions, properties and relations there are. Call the view that it is contingent what individuals there are first-order contingentism, and the view that it is contingent what propositions, properties and relations there are higher-order contingentism. I bring together the three major contributions to the literature on higher-order contingentism, which have been developed largely independently of each other, by Kit Fine, Robert Stalnaker, and Timothy Williamson. I show that a version of Stalnaker's approach to higher-order contingentism was already explored in much more technical detail by Fine, and that it stands up well to the major challenges against higher-order contingentism posed by Williamson. I further show that once a mistake in Stalnaker's development is corrected, each of his models of contingently existing propositions corresponds to the propositional fragment of one of Fine's more general models of contingently existing propositions, properties and relations, and vice versa. I also show that Stalnaker's theory of contingently existing propositions is in tension with his own theory of counterfactuals, but not with one of the main competing theories, proposed by David Lewis. Finally, I connect higher-order contingentism to expressive power arguments against first-order contingentism. I argue that there are intelligible distinctions we draw with talk about "possible things", such as the claim that there are uncountably many possible stars. Since first-order contingentists hold that there are no possible stars apart from the actual stars, they face the challenge of paraphrasing such talk. I show that even in an infinitary higher-order modal logic, the claim that there are uncountably many possible stars can only be paraphrased if higher-order contingentism is false. I therefore conclude that even if first-order contingentism is true, higher-order contingentism is false.

Projektet undersökte hur väl människor kan identifiera objekten bakom inspelade impaktljud i jämförelse med modalt syntetiserade sådana. Undersökningen är rotad i forskning kring fysisk modellering av ljud, men även i estetiska och politiska frågor som berörts av andra forskare inom det akademiska och nyckelpersoner i datorspelsbranschen. En kort historia om syntestekniker som använts inom datorspelsbranschen följer. Ett system för modal analys/omsyntes skapades och användes inom ramen av en kvantitativ undersökning. Även ett tillägprogram för Unity presenteras. Resultaten visar på att modalt syntetiserade impaktljud identifieras med en tillförlitlighet som är jämförbar med inspelningar. En diskussion kring procedurella ljudtekniker inom datorspel och deras för- och nackdelar ur estetiska, praktiska och tekniska synvinklar genomförs. Förslag på framtida arbete presenteras, både som kommersiella samt pedagogiska möjligheter.

Ingeniero Civil / Este trabajo de título se enmarca en el estudio de sistemas de monitoreo de salud estructural, y la influencia que tienen los factores ambientales sobre la identificación de cambios de estado en una estructura, debido a daño, deterioro estructural u otros factores. En estudios previos se ha determinado que la temperatura es la principal variable ambiental que afecta a las frecuencias características de estructuras de hormigón armado. Por esto, en una primera instancia se evaluó experimentalmente el efecto que tiene la temperatura ambiente sobre las frecuencias características de una viga de hormigón armado. Los resultados indican que existe una relación inversa entre estas variables, y que cambios de 30°C generan variaciones de frecuencias del orden del 3%. Se realizaron modelos analíticos de una estructura, a la cual se le modifican sus propiedades en función de la temperatura. En ella se estudió la relevancia de la temperatura en las variaciones de frecuencias debido a distintos grados y tipos de daño. Además se estudió la manera en que la temperatura ambiente y la radiación solar afecta a estructuras de hormigón armado, determinando analíticamente el retraso del efecto de los cambios de temperatura sobre una estructura. Finalmente, se estudiaron los efectos que tienen los factores ambientales en las frecuencias del edificio Torre Central de la FCFM de la Universidad de Chile. Se determinó que las variables más importantes son la temperatura ambiente, la radiación solar y la saturación del suelo. Además, se estudiaron metodologías que permiten detectar cambios de estado en la estructura, considerando los efectos que tiene la temperatura sobre ésta, e identificando los inconvenientes en relación a la modelación de los efectos del aumento de la saturación del suelo producto de precipitaciones. Se estableció que la utilización de metodologías que consideran los efectos ambientales es potencialmente útil, pero para que éstas entreguen resultados confiables se requiere una cantidad de datos para su entrenamiento mayor a dos años.

Magíster en Ciencias de la Ingeniería, Mención Ingeniería Sísmica. Ingeniero Civil / Este estudio presenta la implementación de una metodología desarrollada recientemente y que asegura la identificación de parámetros modales (frecuencia, amortiguamiento y forma modal), bajo el concepto de funciones de transmisibilidad. Esta técnica está concebida para ser implementada en un contexto tipo OMA (Output Modal Analysis), esto significa que no hay necesidad de determinar el input asociado a un sistema, permitiendo así realizar estimaciones durante el régimen operacional de una estructura. La principal ventaja de este método yace en la ausencia de suposiciones respecto a la naturaleza de la excitación, lo cual es un factor común en la mayoría de los métodos tipo OMA, donde regularmente se asume la solicitación como un proceso estocástico de ruido blanco. Para llevar a cabo este trabajo se analizaron los diversos aportes realizados hasta la fecha, de tal forma de generar una metodología clara y eficiente para la detección de parámetros modales. Esto involucra tanto a las funciones de transmisibilidad, así como los estimadores paramétricos que pueden ser empleados sobre dichas funciones para extraer la información modal. Considerando los diversos experimentos realizados en cada uno de los estudios relativos al concepto de transmisibilidad, se intentó extrapolar el uso del método a una estructura de tipo civil, y por lo tanto de gran envergadura, contrariamente a lo desarrollado en la mayoría de los estudios previos, donde se ha aplicado la metodología a estructuras/componentes menores relacionados a la industria automotriz, así como aeroespacial. Para poder realizar lo anterior, se utilizaron los registros de aceleraciones existentes del monitoreo continuo del edificio Torre Central, ubicado en las dependencias de facultad de Ingeniería de la Universidad de Chile. Tomando en cuenta el requisito principal del método, el cual corresponde a identificar más de una condición de carga presente en la estructura, se estudió la factibilidad de considerar el conjunto de respuestas frente a solicitaciones sísmicas, uso diurno y nocturno, resultando lo suficientemente distintas en su distribución espacial, y por lo tanto útiles, para llevar a cabo el proceso de identificación de manera satisfactoria. Los resultados muestran que el uso de funciones de transmisibilidad sólo permite conocer de manera confiable valores frecuencias naturales amortiguadas y las formas modales respectivas. La combinación de escenarios de carga con distinto nivel de excitación impide asegurar invarianza en el tiempo para sistemas cuyo nivel de amortiguamiento dependa del nivel de respuesta que éstos experimenten.

Abstract In this research report, the author defends Peter van Inwagen’s modal skepticism. Van Inwagen accepts that we have much basic, everyday modal knowledge, but denies that we have the capacity to justify philosophically interesting modal claims that are far removed from this basic knowledge. The author also defends the argument by means of which van Inwagen supports his modal skepticism. Van Inwagen argues that Stephen Yablo’s recent and influential account of the relationship between conceivability and possibility supports his skeptical claims. The author’s defence involves a creative interpretation and development of Yablo’s account, which results in a recursive account of modal epistemology, what the author calls the “safe explanation” model of modal epistemology. The defence of van Inwagen’s argument also involves a rebuttal to objections offered to van Inwagen by Geirrson and Sosa.