37 research outputs found

    Ubiquitous Mesh Networking: application to mobile communication and information dissemination in a rural context

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    ICT has furthered the social and economic development of societies but, rural African communities have lagged behind due to issues such as sparse population, low household income, a lack of electricity and other basic infrastructure that make it unattractive for telecommunication service providers to extend service provision. Where the service is available, ubiquitous service coverage has not translated into ubiquitous access for individuals because of the associated costs. A community-wide WMN offering VoIP using fixed telephone handsets has been deployed as a viable alternative to the cellular service provider. The effectiveness of this WMN VoIP service springs from the mobile phone usage statistics which showed that the majority of calls made are intra-community. This dissertation has been an effort towards improved communication and access to information for the under-served communities. Key contributions include, mobile VoIP support, translation gateway deployment to make textual information accessible in voice form via the phone, IP-based radio for community information dissemination. The lack of electricity has been mitigated by the use of low-power devices. In order to circumvent the computational challenges posed by the processing and storage limitations of these devices, a decentralised system architecture whereby the processing and storage load are distributed across the mesh nodes has been proposed. High-performance equipment can be stationed at the closest possible place with electricity in the area and connectivity extended to the non-electrified areas using low-power mesh networking devices. Implementation techniques were investigated and performance parameters measured. The quality of service experienced by the user was assessed using objective methods and QoS correlation models. A MOS value of 4.29, i.e. very good, was achieved for the mobile VoIP call quality, with the underlying hardware supporting up to 15 point-to-point simultaneous calls using SIP and the G.711 based codec. Using the PEAQ algorithm to evaluate the IP-based radio, a PEAQ value of 4.15, i.e. good, was achieved. Streaming audio across the network reduces the available bandwidth by 8Kbps per client due to the unicast nature of streaming. Therefore, a multicast approach has been proposed for efficient bandwidth utilization. The quality of the text-to-voice service rendered by the translation gateway had a PESQ score of 1.6 i.e. poor. The poor performance can be attributed to the TTS engine implementation and also to the lack of robustness in the time-alignment module of the PESQ algorithm. The dissertation also proposes the use of the WMN infrastructure as a back-haul to isles of WSNs deployed in areas of interest to provide access to information about environmental variables useful in decision making

    Web application user interface technologies

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    The World Wide Web has expanded from a huge information storage repository into a worldwide application platform. Web applications have several benefits compared to desktop applications. An application can be used anywhere from any system and device, which means that only one version is needed, they do not need to be installed and developers can modify running applications. Despite all the benefits of the Web, web applications are suffering because they are developed using the same technologies as the static documents on the Web. Some of these web technologies are outdated and were not originally designed for the complex use cases of the modern applications to which they are now applied. For instance, HTML forms comprise the main interaction of an application, despite not having been designed to describe complex and interactive UIs. Another example is HTTP communication on the Web, which always requires client initiative and is too restrictive for dynamic web applications. Additionally, new usage contexts have brought with them new requirements for web applications, which are no longer used only via Graphical User Interfaces. Recently, several parties have developed specialized technologies for web application development. These solutions are not only minor additions to the existing technologies, but also new technologies. The goal of this thesis is to analyze the advanced web technologies and propose improvements to the technologies and architecture where applicable. The technologies are evaluated against a large set of requirements. The aim of the evaluation is two-fold. The first part is to select a technology on which to base the further improvements, and the second is to identify the deficiencies of the current solutions. The improvements focus on the developers' point-of-view. Based on the evaluation, this thesis proposes certain improvements related to multimodal interaction, server push, and remote UI updates. It also discusses software that supports the improvements and XML-based web technologies. Finally, the improvements are evaluated against the requirements and compared to other solutions

    Analysis and Design of Speech-Recognition Grammars

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    Currently, most commercial speech-enabled products are constructed using grammar-based technology. Grammar design is a critical issue for good recognition accuracy. Two methods are commonly used for creating grammars: 1) to generate them automatically from a large corpus of input data which is very costly to acquire, or 2) to construct them using an iterative process involving manual design, followed by testing with end-user speech input. This is a time-consuming and very expensive process requiring expert knowledge of language design, as well as the application area. Another hurdle to the creation and use of speech-enabled applications is that expertise is also required to integrate the speech capability with the application code and to deploy the application for wide-scale use. An alternative approach, which we propose, is 1) to construct them using the iterative process described above, but to replace end-user testing by analysis of the recognition grammars using a set of grammar metrics which have been shown to be good indicators of recognition accuracy, 2) to improve recognition accuracy in the design process by encoding semantic constraints in the syntax rules of the grammar, 3) to augment the above process by generating recognition grammars automatically from specifications of the application, and 4) to use tools for creating speech-enabled applications together with an architecture for their deployment which enables expert users, as well as users who do not have expertise in language processing, to easily build speech applications and add them to the web

    PRESTK : situation-aware presentation of messages and infotainment content for drivers

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    The amount of in-car information systems has dramatically increased over the last few years. These potentially mutually independent information systems presenting information to the driver increase the risk of driver distraction. In a first step, orchestrating these information systems using techniques from scheduling and presentation planning avoid conflicts when competing for scarce resources such as screen space. In a second step, the cognitive capacity of the driver as another scarce resource has to be considered. For the first step, an algorithm fulfilling the requirements of this situation is presented and evaluated. For the second step, I define the concept of System Situation Awareness (SSA) as an extension of Endsley’s Situation Awareness (SA) model. I claim that not only the driver needs to know what is happening in his environment, but also the system, e.g., the car. In order to achieve SSA, two paths of research have to be followed: (1) Assessment of cognitive load of the driver in an unobtrusive way. I propose to estimate this value using a model based on environmental data. (2) Developing model of cognitive complexity induced by messages presented by the system. Three experiments support the claims I make in my conceptual contribution to this field. A prototypical implementation of the situation-aware presentation management toolkit PRESTK is presented and shown in two demonstrators.In den letzten Jahren hat die Menge der informationsanzeigenden Systeme im Auto drastisch zugenommen. Da sie potenziell unabhängig voneinander ablaufen, erhöhen sie die Gefahr, die Aufmerksamkeit des Fahrers abzulenken. Konflikte entstehen, wenn zwei oder mehr Systeme zeitgleich auf limitierte Ressourcen wie z. B. den Bildschirmplatz zugreifen. Ein erster Schritt, diese Konflikte zu vermeiden, ist die Orchestrierung dieser Systeme mittels Techniken aus dem Bereich Scheduling und Präsentationsplanung. In einem zweiten Schritt sollte die kognitive Kapazität des Fahrers als ebenfalls limitierte Ressource berücksichtigt werden. Der Algorithmus, den ich zu Schritt 1 vorstelle und evaluiere, erfüllt alle diese Anforderungen. Zu Schritt 2 definiere ich das Konzept System Situation Awareness (SSA), basierend auf Endsley’s Konzept der Situation Awareness (SA). Dadurch wird erreicht, dass nicht nur der Fahrer sich seiner Umgebung bewusst ist, sondern auch das System (d.h. das Auto). Zu diesem Zweck m¨ussen zwei Bereiche untersucht werden: (1) Die kognitive Belastbarkeit des Fahrers unaufdringlich ermitteln. Dazu schlage ich ein Modell vor, das auf Umgebungsinformationen basiert. (2) Ein weiteres Modell soll die Komplexität der präsentierten Informationen bestimmen. Drei Experimente stützen die Behauptungen in meinem konzeptuellen Beitrag. Ein Prototyp des situationsbewussten Präsentationsmanagement-Toolkits PresTK wird vorgestellt und in zwei Demonstratoren gezeigt

    Mukautuvat XML-pohjaiset multimediapalvelut

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    The emergence of mobile computing requires new kinds of technologies for building services. HTML has been traditionally used to describe documents on the Internet, but it can no longer fulfil these new demands. New mobile devices are compact and limited in respect of processing power, screen size and navigation. Content has to be separated from the layout for the services to be accessible from various computing environments and devices. Web standards are already moving towards XML technology. The flexibility of these new XML-related standards makes it possible to create new kind of platform independent services. However, some of the standards are relatively new and haven't really been tested in practice, not to mention how well they work together. An interactive multimedia service was built to demonstrate some of the new standards. This demonstration service features XML, XSL, ECMAScript and XForms standards. Evaluation of the service showed that all the used standards work smoothly together. Adaptive multimedia services can be created using these technologies. However, the downside at the moment is the lack of proper tools. Especially XSL FO and XForms are very complicated and require a lot of studying. Before powerful and easy-to-use tools are available, developing services can be quite troublesome.Langattoman viestinnän yleistyminen vaatii uudenlaisia tekniikoita palvelujen rakentamiseen. HTML:ää on perinteisesti käytetty dokumenttien kuvauskielenä internetissä, mutta se ei enää pysty tyydyttämään uudenlaisia vaatimuksia. Uudet langattomat päätelaitteet ovat pienikokoisia ja niillä on rajallisesti prosessointitehoa sekä tavallisesta työasemasta poikkeavia navigointitapoja. Sisältö ja ulkoasu täytyy pystyä erottamaan toisistaan, jotta palveluja voitaisiin käyttää erilaisissa laiteympäristöissä. WWW-standardit ovat jo nyt siirtymässä kohti XML-yhteensopivia tekniikoita, mahdollistaa uudentyyppisten laiteriippumattomien palvelujen rakentamisen. Jotkut näistä standardeista ovat kuitenkin varsin tuoreita eikä niitä ole käytännössä. Niiden yhteensopivuudestakaan ei ole vielä paljon kokemuksia. Uusien tekniikoiden arvioimiseksi rakennettiin interaktiivinen multimediapalvelu, jossa on käytetty XML, XSL, ECMAScript ja XForms standardeja. Palvelun arviointi näytti, että käytetyt tekniikat toimivat hyvin yhdessä. Näitä tekniikoita käyttämällä voidaan rakentaa mukautuvia multimediapalveluja. Huonoksi puoleksi havaittiin se, että sopivia työkaluja ei vielä ole. Erityisesti XSL FO ja XForms ovat varsin monimutkaisia ja vaativat paljon perehtymistä. Palvelujen rakentaminen voi olla melko työlästä ennen kuin tehokkaita ja helppokäyttöisiä työkaluja on saatavilla

    Web Application Framework in Erasmus

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    This thesis introduces a new framework in Erasmus which is specially designed for web application. Erasmus, as a typical process oriented language, developed by Peter Grogono at Concordia University, Canada and Brian Shearing at The Software Factory, UK, is based on communicating processes. Erasmus can easily and clearly depict multi-process scenarios based on new concepts: protocol, port, cell and processes. In this thesis, we gave detail of the language Erasmus and explained the new concepts: Cell, Process, Protocol and Port which is introduced by Erasmus. Then, we introduced the Broker which is a proxy to communicate between the processes on different machines and listen for HTTP requests. Next, we depicted the architecture and the resource management of the Erasmus Web application including database access and dynamic process creating. At the end, we gave an example of a simple web application with simple Erasmus language and with an Erasmus MVC framework. As a conclusion, Erasmus is a potential excellent Web development language which can improves the performance of the web services and also helps developers to be more productive in developing web applications

    A flexible and reusable framework for dialogue and action management in multi-party discourse

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    This thesis describes a model for goal-directed dialogue and activity control in real-time for multiple conversation participants that can be human users or virtual characters in multimodal dialogue systems and a framework implementing the model. It is concerned with two genres: task-oriented systems and interactive narratives. The model is based on a representation of participant behavior on three hierarchical levels: dialogue acts, dialogue games, and activities. Dialogue games allow to take advantage of social conventions and obligations to model the basic structure of dialogues. The interactions can be specified and implemented using reoccurring elementary building blocks. Expectations about future behavior of other participants are derived from the state of active dialogue games; this can be useful for, e. g., input disambiguation. The knowledge base of the system is defined in an ontological format and allows individual knowledge and personal traits for the characters. The Conversational Behavior Generation Framework implements the model. It coordinates a set of conversational dialogue engines (CDEs), where each participant is represented by one CDE. The virtual characters can act autonomously, or semi-autonomously follow goals assigned by an external story module (Narrative Mode). The framework allows combining alternative specification methods for the virtual characters\u27; activities (implementation in a general-purpose programming language, by plan operators, or in the specification language Lisa that was developed for the model). The practical viability of the framework was tested and demonstrated via the realization of three systems with different purposes and scope.Diese Arbeit beschreibt ein Modell für zielgesteuerte Dialog- und Ablaufsteuerung in Echtzeit für beliebig viele menschliche Konversationsteilnehmer und virtuelle Charaktere in multimodalen Dialogsystemen, sowie eine Softwareumgebung, die das Modell implementiert. Dabei werden zwei Genres betrachtet: Task-orientierte Systeme und interaktive Erzählungen. Das Modell basiert auf einer Repräsentation des Teilnehmerverhaltens auf drei hierarchischen Ebenen: Dialogakte, Dialogspiele und Aktivitäten. Dialogspiele erlauben es, soziale Konventionen und Obligationen auszunutzen, um die Dialoge grundlegend zu strukturieren. Die Interaktionen können unter Verwendung wiederkehrender elementarer Bausteine spezifiziert und programmtechnisch implementiert werden. Aus dem Zustand aktiver Dialogspiele werden Erwartungen an das zukünftige Verhalten der Dialogpartner abgeleitet, die beispielsweise für die Desambiguierung von Eingaben von Nutzen sein können. Die Wissensbasis des Systems ist in einem ontologischen Format definiert und ermöglicht individuelles Wissen und persönliche Merkmale für die Charaktere. Das Conversational Behavior Generation Framework implementiert das Modell. Es koordiniert eine Menge von Dialog-Engines (CDEs), wobei jedem Teilnehmer eine CDE zugeordet wird, die ihn repräsentiert. Die virtuellen Charaktere können autonom oder semi-autonom nach den Zielvorgaben eines externen Storymoduls agieren (Narrative Mode). Das Framework erlaubt die Kombination alternativer Spezifikationsarten für die Aktivitäten der virtuellen Charaktere (Implementierung in einer allgemeinen Programmiersprache, durch Planoperatoren oder in der für das Modell entwickelten Spezifikationssprache Lisa). Die Praxistauglichkeit des Frameworks wurde anhand der Realisierung dreier Systeme mit unterschiedlichen Zielsetzungen und Umfang erprobt und erwiesen
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