This thesis is a study of sonification and information: what they are and how they relate to each other. The pragmatic purpose of the work is to support a new generation of software tools that are can play an active role in research and practice that involves understanding information structures found in potentially vary large multivariate datasets. The theoretical component of the work involves a review of the way the concept of information has changed through Western culture, from the Ancient Greeks to recent collaborations between cognitive science and the philosophy of mind, with a particular emphasis on the phenomenology of immanent abstractions and how they might be supported and enhanced using sonification techniques. A new software framework is presented, together with several examples of its use in presenting sonifications of financial information, including that from a high-frequency securities-exchange trading-engine.

Scattered data collected at sample points may be used to determine simple functions to best fit the data. An ideal choice for these simple functions is bivariate splines. Triangulation of the sample points creates partitions over which the bivariate splines may be defined. But the optimality of the approximation is dependent on the choice of triangulation. An algorithm, referred to as an Edge Swapping Algorithm, has been developed to transform an arbitrary triangulation of the sample points into an optimal triangulation for representation of the scattered data. A Matlab package has been completed that implements this algorithm for any triangulation on a given set of sample points.

<p> This thesis details the application of computational methods to the problem of determining custom data representations when building hardware accelerators for numerical computations. A majority of scientific applications which require hardware acceleration are implemented in IEEE-754 double precision. However, in many cases the error tolerance requirements of the application are much less than the accuracy which IEEE-754 double precision provides. By leveraging custom data representations, a more resource efficient hardware implementation arises thereby enabling greater parallelism and thus higher performance of the accelerator. </p> <p> The existing custom representation methods are unable to guarantee robust representations while at the same time adequately supporting ill-conditioned operators. Support for both of these scenarios is necessary for accelerating scientific calculations. To address this, we propose the use of a computational method based on Satisfiability-Modulo Theory (SMT). By capturing a calculation as a set of constraints, an SMT instance can be formulated which provides meaningful bounds even in the presence of ill-conditioned operators. At the same time, the analytical nature of SMT satisfies the need for robustness. Utilizing block vector arithmetic, our SMT approach is extended to provide scalability to large instances involving vector calculus which arise in scientific calculations. Atop this foundation, a unified error model is proposed which deals simultaneously with absolute and relative error, thereby providing the means of supporting both fixed-point and custom floating-point data types. Iterative algorithm analysis is leveraged to derive constraints for the SMT method. The application of the method to several scientific algorithms is discussed by way of case studies. </p> / Thesis / Doctor of Philosophy (PhD)

The ongoing digitization of healthcare, which has been much accelerated by the widespread adoption of electronic health records, generates unprecedented amounts of clinical data in a readily computable form. This, in turn, affords great opportunities for making meaningful secondary use of clinical data in the endeavor to improve healthcare, as well as to support epidemiology and medical research. To that end, there is a need for techniques capable of effectively and efficiently analyzing large amounts of clinical data. While machine learning provides the necessary tools, learning effective predictive models from electronic health records comes with many challenges due to the complexity of the data. Electronic health records contain heterogeneous and longitudinal data that jointly provides a rich perspective of patient trajectories in the healthcare process. The diverse characteristics of the data need to be properly accounted for when learning predictive models from clinical data. However, how best to represent healthcare data for predictive modeling has been insufficiently studied. This thesis addresses several of the technical challenges involved in learning effective predictive models from electronic health records. Methods are developed to address the challenges of (i) representing heterogeneous types of data, (ii) leveraging the concept hierarchy of clinical codes, and (iii) modeling the temporality of clinical events. The proposed methods are evaluated empirically in the context of detecting adverse drug events in electronic health records. Various representations of each type of data that account for its unique characteristics are investigated and it is shown that combining multiple representations yields improved predictive performance. It is also demonstrated how the information embedded in the concept hierarchy of clinical codes can be exploited, both for creating enriched feature spaces and for decomposing the predictive task. Moreover, incorporating temporal information leads to more effective predictive models by distinguishing between event occurrences in the patient history. Both single-point representations, using pre-assigned or learned temporal weights, and multivariate time series representations are shown to be more informative than representations in which temporality is ignored. Effective methods for representing heterogeneous and longitudinal data are key for enhancing and truly enabling meaningful secondary use of electronic health records through large-scale analysis of clinical data.

Physics engines have become increasingly prevalent in everyday technology. In the context of this thesis they are regarded as a readily available data set that has the potential to intuitively present the process of sonification to a wide audience. Unfortunately, this process is not the focus of attention when formative decisions are made concerning the continued development of these engines. This may reveal a missed opportunity when considering that the field of interactive sonification upholds the importance of physical causalities for the analysis of data through sound. The following investigation deliberates the contextual framework of this field to argue that the physics engine, as part of typical game engine architecture, is an appropriate foundation on which to design and implement a dynamic toolset for interactive sonification. The basis for this design is supported by a number of significant theories which suggest that the underlying data of a rigid body dynamics physics system can sustain an inherent audiovisual metaphor for interaction, interpretation and analysis. Furthermore, it is determined that this metaphor can be enhanced by the extraordinary potential of the computer in order to construct unique abstractions which build upon the many pertinent ideas and practices within the surrounding literature. These abstractions result in a mental model for the transformation of data to sound that has a number of advantages in contrast to a physical modelling approach while maintaining its same creative potential for instrument building, composition and live performance. Ambitions for both sonification and its creative potential are realised by several components which present the user with a range of options for interacting with this model. The implementation of these components effectuates a design that can be demonstrated to offer a unique interpretation of existing strategies as well as overcoming certain limitations of comparable work.

Cette thèse présente une nouvelle représentation appeléesoupe de polygones déformables pour les applications telles que 3DTV et FTV (Free Viewpoint TV). La soupe de polygones prend en compte les problèmes de compacité, efficacité de compression, et synthèse de vue. Les polygones sont définis en 2D avec des valeurs de profondeurs à chaque coin. Ils ne sont pas nécessairement connectés entre eux et peuvent se déformer en fonction du point de vue et de l'instant dans la séquence vidéo. A partir de données multi-vues plus profondeur (MVD), la construction tient en deux étapes: la décomposition en quadtree et la réduction des redondances inter-vues. Un ensemble compact de polygones est obtenu à la place des cartes de profondeur, tout en préservant les discontinuités de profondeurs et les détails géométriques. Ensuite, l'efficacité de compression et la qualité de synthèse de vue sont évaluées. Des méthodes classiques comme l'\emph{inpainting} et des post-traitements sont implémentées et adaptées à la soupe de polygones. Une nouvelle méthode de compression est proposée. Elle exploite la structure en quadtree et la prédiction spatiale. Les résultats sont comparés à un schéma de compression MVD utilisant le standard MPEG H.264/MVC. Des valeurs de PSNR légèrement supérieures sont obtenues à moyens et hauts débits, et les effets fantômes sont largement réduits. Enfin, la soupe de polygone est déformée en fonction du point de vue désiré. Cette géométrie dépendante du point de vue est guidée par l'estimation du mouvement entre les vues synthétisées et originales. Cela réduit les artefacts restants et améliore la qualité d'image.

Over the last decades computer based tools have been introduced to facilitate systems engineering processes. There are computer based tools for assisting engineers in virtually every aspect of the systems engineering process from requirement elicitation and analysis, over functional analysis, synthesis, implementation and verification. It is not uncommon for a tool to provide many services covering more than one aspect of systems engineering. There exist numerous situations where information exchanges across tool boundaries are valuable, e.g., exchange of specifications between organisations using heterogeneous tool sets, exchange of specifications from legacy to modern tools, exchange of pecifications to tools that provide more advanced modelling or analysis capabilities than the originating tool or storage of specification data in a neutral format such that multiple tools can operate on the data. The focus in this thesis is on the analysis, design and implementation of a method and tool neutral information model for enabling systems engineering tool data exchange. The information model includes support for representation of requirements, system functional architecture and physical architecture, and verification and validation data. There is also support for definition of multiple system viewpoints, representation of system architecture, traceability information and version and configuration management. The applicability of the information model for data exchange hasbeen validated through implementation of tool interfaces to COTS and proprietary systems engineering tools, and exchange of real specifications in different scenarios. The results obtained from the validation activities indicate that systems engineering tool data exchange may decrease the time spent for exchanging specifications between partners developing complex systems and that the information model approach described in the thesis is a compelling alternative to tool specific interfaces.

<p>XML was designed to be a new standard for marking up data on the web. However, as a result of its extensible and flexible properties, XML is now being used more and more for other purposes than was originally intended. Today XML is prompting an approach more focused on data exchange, between different applications inside companies or even between cooperating businesses.</p><p>Businesses are showing interest in using XML as an integral part of their work. Ericsson Microwave Systems (EMW) is a company that sees XML as a conceivable solution to problems in the work with radar communications. An approach towards a solution based on a relational database system has earlier been analysed.</p><p>In this project we present an investigation of the work at EMW, and identification and documentation of the problems in the radar communication work. Also, the requirements and expectations that EMW has on XML are presented. Moreover, an analysis has been made to decide to what extent XML could be used to solve the problems of EMW. The analysis was conducted by elucidating the problems and possibilities of XML compared to the previous approach for solving the problems at EMW, which was based on using a relational database management system.</p><p>The analysis shows that XML has good features for representing hierarchically structured data, as in the EMW case. It is also shown that XML is good for data integration purposes. Furthermore, the analysis shows that XML, due to its self-describing and weak typing nature, is inappropriate to use in the data semantics and integrity problem context of EMW. However, it also shows that the new XML Schema standard could be used as a complement to the core XML standard, to partially solve the semantics problems.</p>

Σκοπός της παρούσας εργασίας, αποτελεί η κατανόηση και η μελέτη των Γεωγραφικών Πληροφοριακών Συστημάτων (ΓΠΣ), και εν συνεχεία η ανάπτυξη μιας διαδικτυακής εφαρμογής, χρησιμοποιώντας συγκεκριμένα χαρακτηριστικά των ΓΠΣ. Πιο συγκεκριμένα, έχοντας μια σαφή εικόνα των χαρακτηριστικών των ΓΠΣ, προχωρούμε στον σχεδιασμό και την υλοποίηση μιας εφαρμογής, που ως στόχο έχει την τμηματοποίηση και τον διαχωρισμό του χάρτη μιας δοθείσας περιοχής αστικού περιβάλλοντος, σε άλλες μικρότερες περιοχές. Ο διαχωρισμός αυτός δεν ακολουθεί μια αυθαίρετη λογική κατάτμησης, αλλά βασίζεται στον διαχωρισμό σε πολεοδομικά τετράγωνα, δημιουργώντας έτσι μικρότερες περιοχές ενδιαφέροντος. Στο παρελθόν έχουν υλοποιηθεί αρκετές τεχνικές αναπαράστασης της χωρικής πληροφορίας πάνω στον χάρτη, όπως οι Heat Maps, οι Dot Density Maps, οι Proportional Symbol Maps, κ.ά. Ωστόσο, αν και σε πολλές περιπτώσεις είναι αρκετά αποδοτικές αυτές οι τεχνικές, συνήθως είναι δυσνόητες και ασαφείς ως προς την κατανόησή τους από μη-ειδικούς χρήστες. Στην εργασία αυτή, σε κάθε νέα περιοχή ενδιαφέροντος (πολεοδομικά τετράγωνα), προσδίδεται ένας χρωματισμός, ανάλογα με τα δεδομένα που εξάγουμε από τα μέσα κοινωνικής δικτύωσης, μια τεχνική όπου είναι εύληπτη και κατανοητή από τον άνθρωπο, και μπορεί μέσω αυτής να εξάγει εύκολα συμπεράσματα. / The purpose of this work is to understand and study Geographic Information Systems (GIS), and subsequently to develop a web application, using specific characteristics of GIS. More specifically, having a clear picture of the characteristics of GIS, we proceed to the design and implementation of an application, which aims to segment and separate a given urban map area to other smaller one areas. This division does not follow an arbitrary logical partition, but is based on the separation in urban squares, thus creating smaller areas of interest. In the past, several techniques have been implemented for representing of spatial information on the map, such as HeatMaps, Dot Density Maps, Proportional Symbol Maps, etc. However, although in many cases these are quite effective, these techniques are usually obscure and unclear in their understanding of non-skilled users. In this work, in each new region of interest (urban squares), imparted a coloring, depending on the data extracted from social networking, a technique which is accessible and understandable by users and easy conclusions can be exported through.

mLearn4web is a web-based framework aiming to support the creation of mobile applications within the field of mobile learning. The framework consists of three main parts; an authoring tool, automatically deployed mobile applications and a visualization tool. The visualization tool was implemented as part of this thesis’ work. The focus of this thesis was to identify visual representations for data collected in mLearn4web activities and to implement these representations in a new visualization tool. The work has had a design-based research approach and was conducted together with teachers as a part of an iterative design process. The work was initiated by a literature review and a study of previous mLearn4web use. A questionnaire was then sent to teachers, where they were asked to rate different visual representations. This was the basis for the development of the visualization tool. Three workshops involving teachers were conducted throughout the process, finally resulting in a functional visualization tool and a set of visual representations that were found appropriate by teachers. Evaluations with experienced teachers show that the visual representations proposed and implemented can be appropriate in an educational setting. To further validate them the tool and its visual representations need to be tested in real-life settings, and should ideally also include students. / mLearn4web