We present an algorithm for deciding whether an arbitrary proper probabilistic context-free grammar is consistent, i.e., whether the probability that a derivation terminates is one. Our procedure has time complexity $\\\\mathcal O(n^3)$ in the unit-cost model of computation. Moreover, we develop a novel characterization of consistent probabilistic context-free grammars. A simple corollary of our result is that training methods for probabilistic context-free grammars that are based on maximum-likelihood estimation always yield consistent grammars.

Everything around us that is not a simple untouched piece of nature has been designed by someone. Human society has found a great refuge in these designed objects or the artefacts, and thus has adapted vociferously to their inclusion into everyday life. From the early conception as art and then lately as scientific activity, now during the last few decades, designing has been understood as a fundamental aspect of human life. This understanding has become a motivating force in the last four decades for design research community. Remarkable theories, methods, models and approaches for designing have been propounded during this period by various active design researchers. Yet a comprehensive design theory remains largely an elusive dream, and usage of proposed methods in practice unimpressive. The dominant paradigms in design theory, though rich in description seem to lack interconnection. The thesis explores and questions the very foundations on which design theories have been built. Theoretical contemplation over designing is sought through asking why question, which brings in context to the forefront. Thus understanding context in designing is the central theme to this dissertation. Incidentally it is the context that holds key to the enhanced usage of design methods in practice. The thesis presents a basis to thaw the development of design theory, and provides a pragmatic approach to augment usage of design methods in practice. These objectives have been achieved through the approach outlined below. • An extensive discussion on the notion of context is presented, underpinned by the detailed survey of definitions and world views held in by various domains of studies in regard to context. The salient characteristics of context identified through this discussion have been used to articulate a concise definition of context. • A comprehensive dialogue, supplemented by the literature in design, incorporating dyv of design, designing, artifacts, and context has been put forth. The theoretical insight obtained has been abstracted into an elemental model of context in designing, that is then elaborated at length. • Definitions of context in designing, context of designing, and that of designing in context have been formulated, using the definition of context and the elemental model of context in designing. • The empirical validation of the proposed model of context in designing has been carried out, which runs across six design projects, accounts for academic; controlled; and industrial environment, as well as focuses on both individual and team designing. Four methods for data collection and analysis - Questionnaire survey, design protocol analysis study, replication protocol analysis, and participant observation study were employed in this exercise. • A detailed prescriptive study for development of aid to designers; in selection process of design methods has been carried out. Based on the issues identified in the literature and survey with designers, a measure to assess contextual usability of design methods (MACUM) was formulated. A web-based software tool based on MACUM has been developed for supporting design method selection process. The thesis concludes that the dominating paradigms in design theory only represent the partial perspective of designing. It is argued that, the proposed model of context in designing provides a sound basis to coherently redress the disjunctions between paradigms of design and progress towards a holistic design theory. And further on the practical end, the thesis underlines the contribution of MACUM towards sustained usage of design methods in practice.

Die "Kontextsensitivität" genannte systematische Berücksichtigung von Umweltinformationen durch Anwendungssysteme kann als Querschnittsfunktion im betrieblichen Umfeld in vielen Bereichen einen Nutzen stiften. Wirklich praxistaugliche kontextsensitive Anwendungssysteme, die sich analog zu einem mitdenkenden menschlichen Assistenten harmonisch in die ablaufenden Vorgänge in der Realwelt einbringen, haben einen enormen Bedarf nach umfassenden, d.h. diverse Aspekte der Realwelt beschreibenden Kontextinformationen, die jedoch prinzipbedingt verteilt in verschiedenen Datenquellen, etwa Kontexterfassungssystemen, Endgeräten sowie prinzipiell auch in beliebigen anderen, z.T. bereits existierenden Anwendungen entstehen. Ziel dieser Arbeit ist die Verringerung der Komplexität des Beschaffungsvorganges von verteilten und heterogenen Kontextinformationen durch Bereitstellung einer einfach verwendbaren Methode zur Darstellung eines umfassenden, aus verteilten und heterogenen Datenquellen zusammengetragenen Kontextmodells. Im Besonderen werden durch diese Arbeit zwei Probleme addressiert, zum einen daß ein Konsument von umfassenden Kontextinformationen mehrere Datenquellen sowohl kennen und zugreifen können und zum anderen über die zwischen den einzelnen Kontextinformationen in verschiedenen Datenquellen existierenden, zunächst nicht modellierten semantischen Verbindungen Bescheid wissen muß. Das dazu entwickelte Kontextinformationsintegrations- und -darstellungsverfahren kombiniert daher ein die Beschaffung und Integration von Kontextinformationen aus diversen Datenquellen modellierendes Informationsintegrationsmodell mit einem Kontextdarstellungsmodell, welches die abzubildende Realweltdomäne basierend auf ontologischen Informationen durch in problemspezifischer Weise erweiterte Verfahren des Semantic Web in einer möglichst intuitiven, wiederverwendbaren und modularen Weise modelliert. Nach einer fundierten Anforderungsanalyse des entwickelten Prinzips wird dessen Verwendung und Nutzen basierend auf der Skizzierung der wichtigsten allgemeinen Verwendungsmöglichkeiten von Kontextinformationen im betrieblichen Umfeld anhand eines komplexen betrieblichen Anwendungsszenarios demonstriert. Dieses beinhaltet ein Nutzerprofil, das von diversen Anwendungen, u.a. einem kontextsensitiven KFZ-Navigationssystem, einer Restaurantsuchanwendung sowie einem Touristenführer verwendet wird. Probleme hinsichtlich des Datenschutzes, der Integration in existierende Umgebungen und Abläufe sowie der Skalierbarkeit und Leistungsfähigkeit des Verfahrens werden ebenfalls diskutiert. / Context-awareness, which is the systematic consideration of information from the environment of applications, can provide significant benefits in the area of business and technology. To be really useful, i.e. harmonically support real-world processes as human assistants do it, practical applications need a comprehensive and detailed contextual information base that describes all relevant aspects of the real world. As a matter of principle, comprehensive contextual information arises in many places and data sources, e.g. in context-aware infrastructures as well as in "normal" applications, which may have knowledge about the context based on their functionality to support a certain process in the real world. This thesis facilitates the use of contextual information by reducing the complexity of the procurement process of distributed and heterogenous contextual information. Particularly, it addresses the two problems that a consumer of comprehensive contextual information needs to be aware of and able to access several different data sources and must know how to combine the contextual information taken from different and isolated data sources into a meaningful representation of the context. Especially the latter information cannot be modelled using the current state of the art. These problems are addressed by the development of an integration and representation model for contextual information that allows to compose comprehensive context models using information inside distributed and heterogeneous data sources. This model combines an information integration model for distributed and heterogenous information (which consists of an access model for heterogeneous data sources, an integration model and an information relation model) with a representation model for context that formalizes the representation of the respective real world domain, i.e. of the real world objects and their semantic relations in an intuitive, reusable and modular way based on ontologies. The resulting model consists of five layers that represent different aspects of the information integration solution. The achievement of the objectives is rated based on a requirement analysis of the problem domain. The technical feasibility and usefulness of the model is demonstrated by the implementation of an engine to support the approach as well as a complex application scenario consisting of a user profile that integrates information from several data sources and a couple of context-aware applications, e.g. a context-aware navigation system, a restaurant finder application as well as an enhanced tourist guide that use the user profile. Problems regarding security and social effects, the integration of this solution into existing environments and infrastructures as well as technical issues like the scalability and performance of this model are discussed too.

This dissertation describes two distinctive methods for human-vehicle interaction recognition: one for ground level videos and the other for aerial videos. For ground level videos, this dissertation presents a novel methodology which is able to estimate a detailed status of a scene involving multiple humans and vehicles. The system tracks their configuration even when they are performing complex interactions with severe occlusion such as when four persons are exiting a car together. The motivation is to identify the 3-D states of vehicles (e.g. status of doors), their relations with persons, which is necessary to analyze complex human-vehicle interactions (e.g. breaking into or stealing a vehicle), and the motion of humans and car doors to detect atomic human-vehicle interactions. A probabilistic algorithm has been designed to track humans and analyze their dynamic relationships with vehicles using a dynamic context. We have focused on two ideas. One is that many simple events can be detected based on a low-level analysis, and these detected events must contextually meet with human/vehicle status tracking results. The other is that the motion clue interferes with states in the current and future frames, and analyzing the motion is critical to detect such simple events. Our approach updates the probability of a person (or a vehicle) having a particular state based on these basic observed events. The probabilistic inference is made for the tracking process to match event-based evidence and motion-based evidence. For aerial videos, the object resolution is low, the visual cues are vague, and the detection and tracking of objects is less reliable as a consequence. Any method that requires accurate tracking of objects or the exact matching of event definition are better avoided. To address these issues, we present a temporal logic based approach which does not require training from event examples. At the low-level, we employ dynamic programming to perform fast model fitting between the tracked vehicle and the rendered 3-D vehicle models. At the semantic-level, given the localized event region of interest (ROI), we verify the time series of human-vehicle relationships with the pre-specified event definitions in a piecewise fashion. With special interest in recognizing a person getting into and out of a vehicle, we have tested our method on a subset of the VIRAT Aerial Video dataset and achieved superior results. / text

The music of the late baroque composer Jan Dismas Zelenka (1679- 1745) was not widely circulated during his lifetime. In the late twentieth century, Zelenka's music experienced a revival due to the rediscovery of his sonatas for double reed ensemble. The thesis examines the stylistic, generic, and historical context for Zelenka's Sonata V (ZWV 181, no. 5), tracing the development of the ensemble sonata for double reeds at the Augustan court. Chapter One focuses on Zelenka's life, as well as the purpose and dating of the six ensemble sonatas for obbligato double reeds (ZWV 181). The subsequent chapter surveys the national styles that were assimilated into the compositional traditions of the Dresden hofkapelle in the early 18th century. The role of the oboist within the court musical establishment and the social status of the hofmusicus are discussed. Chapter Three considers the precedents for and influences on Zelenka's Sonata V, particularly with respect to its inclusion in the little known genre of the sonata auf concertenart. These sonatas in the manner of a concerto adopt the formal outlines of Vivaldi's concertos and concerted sonatas while obscuring the distinctions of genre between the sonata and concerto through the treatment of scoring and texture. Zelenka's Sonata V follows the style of an early sonate auf concertenart of Vivaldi. Zelenka's concerted sonata departs from its model by confounding the identity of the initially distinct ritornello and solo material. The specific use of the oboe in Zelenka's sonatas, including playing techniques, and the degree of specialization are discussed. The conclusion speculates as to why Zelenka's music quickly fell out of favor and why even the composer himself was treated in a critical manner only a few generations after his time at Dresden. An understanding of the Dresden court not only provides a window on Zelenka's music, but also explains its almost immediate eclipse following his death. / text

Mineral projects in the global South have been subjected to increasing opposition, especially from adjacent communities, ultimately forcing some firms to abandon government-permitted and financially viable projects. Consequently, the mining literature has become saturated with prescriptions for firms seeking to engage with impacted communities. This literature is limited in that: it has primarily focused on conflict-ridden situations; the role of context has been largely ignored; and there has been little validation of what works and why. This thesis responds to these limitations through an assessment of the Canadian firm Kinross Gold at Paracatu, Brazil, where company-community relations have seemingly been healthy for years. Kinross has exerted considerable effort to engage with the community through several initiatives. While not all initiatives have been effective, community relations are strong, especially when compared to other foreign-owned mines in Latin America. However, Paracatu also boasts a diversified economy, and positive population and governance characteristics. This research shows that both context and company practice are important in determining company-community relations.

<p>The test context is of paramount importance in language testing as it provides an understanding of the kind of tasks to be included in the test, how these tasks are executed by the test takers and how they can be efficiently administered. The objective of this study was to investigate the extent to which the context of the DR Congo English state examination (ESE) is valid and to come out with some useful suggestions that are likely to improve its validity. Two basic theories, the modern validity theory and the schema theory, informed this study. Weir‟s (2005) socio-cognitive framework was used to build the validity argument for the evaluation of the English state examination.</p> <p>A mixed method was used where the research design consisted of the combination of both qualitative and quantitative data during the collection and analysis stages. The content document analysis method was used to examine the content of the different state examination papers so as to identify the main features of the test, and the statistic (descriptive) method was used to quantify observations identified in the state examination papers and to evaluate the context validity of the ESE. Three techniques were used to collect the research data: the questionnaire, the<br /> test, and the interview.</p> <p>Three main findings of this study were reported: (1) the conditions under which the ESE tasks are performed and the relevance of these tasks to the test domain and characteristics are still far to contribute to the quality of evaluation of high school finalist students / (2) the extent to which the ESE includes tasks that take into consideration the nature of information in the text as well as the knowledge required for completing the task is globally good / (3) the conditions under which the test takes place are poor and these conditions affect the validity of test scores. The study recommends the test developers to approximate test tasks to those students have been exposed to in classroom situations and those they are likely to encounter in real life. It also recommends all the people involved in the administration of the test to adhere to high ethical standards.</p>

Computer screens are very small compared to the size of large information spaces that arise in many domains. The visualization of such datasets requires multiscale navigation capabilities, enabling users to switch between zoomed-in detailed views and zoomed-out contextual views of the data. Designing interfaces that allow users to quickly identify objects of interest, get detailed views of those objects, relate them and put them in a broader spatial context, raise challenging issues. Multi-scale interfaces have been the focus of much research effort over the last twenty years.There are several design approaches to address multiscale navigation issues. In this thesis, we review and categorize these approaches according to their level of content awareness. We identify two main approaches: content-driven, which optimizes interfaces for navigation in specific content; and content-agnostic, that applies to any type of data. We introduce the content-aware design approach, which dynamically adapts the interface to the content. The latter design approach can be used to design multiscale navigation techniques both in 2D or 3D spaces. We introduce Arealens and Pathlens, two content-aware fisheye lenses that dynamically adapt their shape to the underlying content to better preserve the visual aspect of objects of interest. We describe the techniques and their implementation, and report on a controlled experiment that evaluates the usability of Arealens compared to regular fisheye lenses, showing clear performance improvements with the new technique for a multiscale visual search task. We introduce a new distortion-oriented presentation library enabling the design of fisheye lenses featuring several foci of arbitrary shapes. Then, we introduce Gimlens, a multi-view detail-in-context visualization technique that enables users to navigate complex 3D models by drilling holes into their outer layers to reveal objects that are buried into the scene. Gimlens adapts to the geometry of objects of interest so as to better manage visual occlusion problems, selection mechanism and coordination of lenses.

This thesis presents the design and analysis of Spasiba, a context-aware mobile advisor. We argue that current context-aware mobile applications exhibit significant flaws with respect to (1) limited use of context information, (2) incomplete or irrelevant content generation, and (3) low usability. The proposed model attempts to tackle these limitations by advancing the usage and manipulation of context information, automating the back-end systems in terms of self-management and seamless extensibility, and shifting the logic away from the client side. A distinguishing characteristic of Spasiba is the proactive approach to notifying the user of information of interest. In this proactive approach, the user subscribes to the service and receives content updates as the context changes. This proposed model is realised in a proof-of-concept prototype that uses a Nokia Web Runtime widget as the client application. The widget, which sports an elegant, touch-optimised interface, collects multiple context parameters to deliver high-quality results. The server-side architecture employs the publish/subscribe paradigm for managing the active users and Comet—for proactively notifying the clients of updated information of interest. IRS-III, a Semantic Web Services broker, handles the process of content generation. The prototype employs nine data sources, seven of which are open API web services and two of which are regular web pages, to deliver diverse and complete results. A simple autonomic element, implemented with the help of aspect-oriented programming, ensures partial self-management of the back-end systems. Spasiba is evaluated by means of a case study that involves a tourist couple visiting Victoria. The application assists the tourist couple with finding attractions, relevant stores, and places serving food.

Our society is increasingly demanding situation-aware smarter software (SASS) systems, whose goals change over time and depend on context situations. A system with such properties must sense their dynamic environment and respond to changes quickly, accurately, and reliably, that is, to be context-aware and self-adaptive. The problem addressed in this dissertation is the dynamic management of context information, with the goal of improving the relevance of SASS systems' context-aware capabilities with respect to changes in their requirements and execution environment. Therefore, this dissertation focuses on the investigation of dynamic context management and self-adaptivity to: (i) improve context-awareness and exploit context information to enhance quality of user experience in SASS systems, and (ii) improve the dynamic capabilities of self-adaptivity in SASS systems. Context-awareness and self-adaptivity pose signi cant challenges for the engineering of SASS systems. Regarding context-awareness, the rst challenge addressed in this dissertation is the impossibility of fully specifying environmental entities and the corresponding monitoring requirements at design-time. The second challenge arises from the continuous evolution of monitoring requirements due to changes in the system caused by self-adaptation. As a result, context monitoring strategies must be modeled and managed in such a way that they support the addition and deletion of context types and monitoring conditions at runtime. For this, the user must be integrated into the dynamic context management process. Concerning self-adaptivity, the third challenge is to control the dynamicity of adaptation goals, adaptation mechanisms, and monitoring infrastructures, and the way they a ect each other in the adaptation process. This is to preserve the eff ectiveness of context monitoring requirements and thus self-adaptation. The fourth challenge, related also to self-adaptivity,concerns the assessment of adaptation mechanisms at runtime to prevent undesirable system states as a result of self-adaptation. Given these challenges, to improve context-awareness we made three contributions. First, we proposed the personal context sphere concept to empower users to control the life cycle of personal context information in user-centric SASS systems. Second, we proposed the SmarterContext ontology to model context information and its monitoring requirements supporting changes in these models at runtime. Third, we proposed an effi cient context processing engine to discover implicit contextual facts from context information speci fied in changing context models. To improve self-adaptivity we made three contributions. First, we proposed a framework for the identi cation of adaptation properties and goals, which is useful to evaluate self-adaptivity and to derive monitoring requirements mapped to adaptation goals. Second, we proposed a reference model for designing highly dynamic self-adaptive systems, for which the continuous pertinence between monitoring mechanisms and both changing system goals and context situations is a major concern. Third, we proposed a model with explicit validation and veri cation (V&V) tasks for self-adaptive software, where dynamic context monitoring plays a major role. The seventh contribution of this dissertation, the implementation of Smarter-Context infrastructure, addresses both context-awareness and self-adaptivity. To evaluate our contributions, qualitatively and quantitatively, we conducted several comprehensive literature reviews, a case study on user-centric situation-aware online shopping, and a case study on dynamic governance of service-oriented applications. / Graduate