Flexible media transport framework based on service composition for future network

This work introduces common guidelines defined in several standardization organisms towards future networks based on the actual mechanisms and protocols used to treat the multimedia data, most of them placed in the application layer of the OSI reference model.Peer ReviewedPreprin

Adaptive model-driven user interface development systems

Adaptive user interfaces (UIs) were introduced to address some of the usability problems that plague many software applications. Model-driven engineering formed the basis for most of the systems targeting the development of such UIs. An overview of these systems is presented and a set of criteria is established to evaluate the strengths and shortcomings of the state-of-the-art, which is categorized under architectures, techniques, and tools. A summary of the evaluation is presented in tables that visually illustrate the fulfillment of each criterion by each system. The evaluation identified several gaps in the existing art and highlighted the areas of promising improvement

Engineering Adaptive Model-Driven User Interfaces for Enterprise Applications

Enterprise applications such as enterprise resource planning systems have numerous complex user interfaces (UIs). Usability problems plague these UIs because they are offered as a generic off-the-shelf solution to end-users with diverse needs in terms of their required features and layout preferences. Adaptive UIs can help in improving usability by tailoring the features and layout based on the context-of-use. The model-driven UI development approach offers the possibility of applying different types of adaptations on the various UI levels of abstraction. This approach forms the basis for many works researching the development of adaptive UIs. Yet, several gaps were identified in the state-of-the-art adaptive model-driven UI development systems. To fill these gaps, this thesis presents an approach that offers the following novel contributions: - The Cedar Architecture serves as a reference for developing adaptive model-driven enterprise application user interfaces. - Role-Based User Interface Simplification (RBUIS) is a mechanism for improving usability through adaptive behavior, by providing end-users with a minimal feature-set and an optimal layout based on the context-of-use. - Cedar Studio is an integrated development environment, which provides tool support for building adaptive model-driven enterprise application UIs using RBUIS based on the Cedar Architecture. The contributions were evaluated from the technical and human perspectives. Several metrics were established and applied to measure the technical characteristics of the proposed approach after integrating it into an open-source enterprise application. Additional insights about the approach were obtained through the opinions of industry experts and data from real-life projects. Usability studies showed the approach’s ability to significantly improve usability in terms of end-user efficiency, effectiveness and satisfaction

Highly Interactive Web-Based Courseware

Zukünftige Lehr-/Lernprogramme sollen als vernetzte Systeme die Lernenden befähigen, Lerninhalte zu erforschen und zu konstruieren, sowie Verständnisschwierigkeiten und Gedanken in der Lehr-/Lerngemeinschaft zu kommunizieren. Lehrmaterial soll dabei in digitale Lernobjekte übergeführt, kollaborativ von Programmierern, Pädagogen und Designern entwickelt und in einer Datenbank archiviert werden, um von Lehrern und Lernenden eingesetzt, angepasst und weiterentwickelt zu werden. Den ersten Schritt in diese Richtung machte die Lerntechnologie, indem sie Wiederverwendbarkeit und Kompabilität für hypermediale Kurse spezifizierte. Ein größeres Maß an Interaktivität wird bisher allerdings noch nicht in Betracht gezogen. Jedes interaktive Lernobjekt wird als autonome Hypermedia-Einheit angesehen, aufwändig in der Erstellung, und weder mehrstufig verschränk- noch anpassbar, oder gar adäquat spezifizierbar. Dynamische Eigenschaften, Aussehen und Verhalten sind fest vorgegeben. Die vorgestellte Arbeit konzipiert und realisiert Lerntechnologie für hypermediale Kurse unter besonderer Berücksichtigung hochgradig interaktiver Lernobjekte. Innovativ ist dabei zunächst die mehrstufige, komponenten-basierte Technologie, die verschiedenste strukturelle Abstufungen von kompletten Lernobjekten und Werkzeugsätzen bis hin zu Basiskomponenten und Skripten, einzelnen Programmanweisungen, erlaubt. Zweitens erweitert die vorgeschlagene Methodik Kollaboration und individuelle Anpassung seitens der Teilnehmer eines hypermedialen Kurses auf die Software-Ebene. Komponenten werden zu verknüpfbaren Hypermedia-Objekten, die in der Kursdatenbank verwaltet und von allen Kursteilnehmern bewertet, mit Anmerkungen versehen und modifiziert werden. Neben einer detaillierten Beschreibung der Lerntechnologie und Entwurfsmuster für interaktive Lernobjekte sowie verwandte hypermediale Kurse wird der Begriff der Interaktivität verdeutlicht, indem eine kombinierte technologische und symbolische Definition von Interaktionsgraden vorgestellt und daraus ein visuelles Skriptschema abgeleitet wird, welches Funktionalität übertragbar macht. Weiterhin wird die Evolution von Hypermedia und Lehr-/Lernprogrammen besprochen, um wesentliche Techniken für interaktive, hypermediale Kurse auszuwählen. Die vorgeschlagene Architektur unterstützt mehrsprachige, alternative Inhalte, bietet konsistente Referenzen und ist leicht zu pflegen, und besitzt selbst für interaktive Inhalte Online-Assistenten. Der Einsatz hochgradiger Interaktivität in Lehr-/Lernprogrammen wird mit hypermedialen Kursen im Bereich der Computergraphik illustriert.The grand vision of educational software is that of a networked system enabling the learner to explore, discover, and construct subject matters and communicate problems and ideas with other community members. Educational material is transformed into reusable learning objects, created collaboratively by developers, educators, and designers, preserved in a digital library, and utilized, adapted, and evolved by educators and learners. Recent advances in learning technology specified reusability and interoperability in Web-based courseware. However, great interactivity is not yet considered. Each interactive learning object represents an autonomous hypermedia entity, laborious to create, impossible to interlink and to adapt in a graduated manner, and hard to specify. Dynamic attributes, the look and feel, and functionality are predefined. This work designs and realizes learning technology for Web-based courseware with special regard to highly interactive learning objects. The innovative aspect initially lies in the multi-level, component-based technology providing a graduated structuring. Components range from complex learning objects to toolkits to primitive components and scripts. Secondly, the proposed methodologies extend community support in Web-based courseware – collaboration and personalization – to the software layer. Components become linkable hypermedia objects and part of the courseware repository, rated, annotated, and modified by all community members. In addition to a detailed description of technology and design patterns for interactive learning objects and matching Web-based courseware, the thesis clarifies the denotation of interactivity in educational software formulating combined levels of technological and symbolical interactivity, and deduces a visual scripting metaphor for transporting functionality. Further, it reviews the evolution of hypermedia and educational software to extract substantial techniques for interactive Web-based courseware. The proposed framework supports multilingual, alternative content, provides link consistency and easy maintenance, and includes state-driven online wizards also for interactive content. The impact of great interactivity in educational software is illustrated with courseware in the Computer Graphics domain

Flexi-WVSNP-DASH: A Wireless Video Sensor Network Platform for the Internet of Things

abstract: Video capture, storage, and distribution in wireless video sensor networks (WVSNs) critically depends on the resources of the nodes forming the sensor networks. In the era of big data, Internet of Things (IoT), and distributed demand and solutions, there is a need for multi-dimensional data to be part of the Sensor Network data that is easily accessible and consumable by humanity as well as machinery. Images and video are expected to become as ubiquitous as is the scalar data in traditional sensor networks. The inception of video-streaming over the Internet, heralded a relentless research for effective ways of distributing video in a scalable and cost effective way. There has been novel implementation attempts across several network layers. Due to the inherent complications of backward compatibility and need for standardization across network layers, there has been a refocused attention to address most of the video distribution over the application layer. As a result, a few video streaming solutions over the Hypertext Transfer Protocol (HTTP) have been proposed. Most notable are Apple’s HTTP Live Streaming (HLS) and the Motion Picture Experts Groups Dynamic Adaptive Streaming over HTTP (MPEG-DASH). These frameworks, do not address the typical and future WVSN use cases. A highly flexible Wireless Video Sensor Network Platform and compatible DASH (WVSNP-DASH) are introduced. The platform's goal is to usher video as a data element that can be integrated into traditional and non-Internet networks. A low cost, scalable node is built from the ground up to be fully compatible with the Internet of Things Machine to Machine (M2M) concept, as well as the ability to be easily re-targeted to new applications in a short time. Flexi-WVSNP design includes a multi-radio node, a middle-ware for sensor operation and communication, a cross platform client facing data retriever/player framework, scalable security as well as a cohesive but decoupled hardware and software design.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201

A Framework for Model-Driven Development of Mobile Applications with Context Support

Model-driven development (MDD) of software systems has been a serious trend in different application domains over the last 15 years. While technologies, platforms, and architectural paradigms have changed several times since model-driven development processes were first introduced, their applicability and usefulness are discussed every time a new technological trend appears. Looking at the rapid market penetration of smartphones, software engineers are curious about how model-driven development technologies can deal with this novel and emergent domain of software engineering (SE). Indeed, software engineering of mobile applications provides many challenges that model-driven development can address. Model-driven development uses a platform independent model as a crucial artifact. Such a model usually follows a domain-specific modeling language and separates the business concerns from the technical concerns. These platform-independent models can be reused for generating native program code for several mobile software platforms. However, a major drawback of model-driven development is that infrastructure developers must provide a fairly sophisticated model-driven development infrastructure before mobile application developers can create mobile applications in a model-driven way. Hence, the first part of this thesis deals with designing a model-driven development infrastructure for mobile applications. We will follow a rigorous design process comprising a domain analysis, the design of a domain-specific modeling language, and the development of the corresponding model editors. To ensure that the code generators produce high-quality application code and the resulting mobile applications follow a proper architectural design, we will analyze several representative reference applications beforehand. Thus, the reader will get an insight into both the features of mobile applications and the steps that are required to design and implement a model-driven development infrastructure. As a result of the domain analysis and the analysis of the reference applications, we identified context-awareness as a further important feature of mobile applications. Current software engineering tools do not sufficiently support designing and implementing of context-aware mobile applications. Although these tools (e.g., middleware approaches) support the definition and the collection of contextual information, the adaptation of the mobile application must often be implemented by hand at a low abstraction level by the mobile application developers. Thus, the second part of this thesis demonstrates how context-aware mobile applications can be designed more easily by using a model-driven development approach. Techniques such as model transformation and model interpretation are used to adapt mobile applications to different contexts at design time or runtime. Moreover, model analysis and model-based simulation help mobile application developers to evaluate a designed mobile application (i.e., app model) prior to its generation and deployment with respected to certain contexts. We demonstrate the usefulness and applicability of the model-driven development infrastructure we developed by seven case examples. These showcases demonstrate the designing of mobile applications in different domains. We demonstrate the scalability of our model-driven development infrastructure with several performance tests, focusing on the generation time of mobile applications, as well as their runtime performance. Moreover, the usability was successfully evaluated during several hands-on training sessions by real mobile application developers with different skill levels

Concur: An Investigation of Lightweight Migration in Support of Centralized Synchronous Distributed Collaboration

Synchronous distributed collaborative systems support simultaneous observation of and interaction with shared objects by multiple, dispersed participants. Centralized architectures for such systems support simple user mental models and are comparatively easy to implement, but they suffer from high latency. Replicated architectures improve latency at the expense of more complex user mental models and implementations. Hybrid and dynamic architectures apply centralized and replicated sub-architectures in an attempt to get the best of both worlds, but in reality they further complicate implementations and user mental models. Concur is an architecture I developed to investigate lightweight migration as an alternative means to attain the best characteristics of centralized and replicated architectures. Previous dynamic architectures improved latency using the migration of heavyweight processes or (object-oriented) objects, which is costly in terms of migration time and runtime requirements. In Concur I have instead organized collaborative applications and supporting infrastructures around migrating entities which are not required to have full process or object semantics. These entities are classified by properties affecting migration, such as their size and their use of external references. In this way I achieved both the simpler user mental models and implementations of centralized systems and the superior latency characteristics of replicated systems. Concur accomplishes this through the fast migration of lightweight entities in a multi-centered centralized system, where a multi-centered system is defined as having single physical center and multiple, independently-migrating and entity-specific logical centers. This dissertation also identifies other significant advantages of the Concur architecture. Sub-object, easily-migratable entity classes minimize runtime requirements, facilitating widespread entity distribution. This in turn helps us to achieve the critical mass required for the success of any communication technology. The speed of lightweight entity migration also enables migrations to be triggered based on telegraphed user intentions (user actions that hint at imminent succeeding actions). I have demonstrated that telegraphed intentions are more accurate predictors of future interactions than the recent interaction histories considered in previous systems. Migrating entities based on these telegraphed intentions increases the probability that an entity will be located near a user when he begins to manipulate it

HIVE-MIND SPACE: A META-DESIGN APPROACH FOR CULTIVATING AND SUPPORTING COLLABORATIVE DESIGN.

The ever-growing complexity of design projects requires more knowledge than any individual can have and, therefore, needs the active engagement of all stakeholders in the design process. Collaborative design exploits synergies from multidisciplinary communities, encourages divergent thinking, and enhances social creativity. The research documented in this thesis supports and deepens the understanding of collaborative design in two dimensions: (1) It developed and evaluated socio-technical systems to support collaborative design projects; and (2) It defined and explored a meta- design framework focused on how these systems enable users, as active contributors, to modify and further develop them. The research is grounded in and simultaneously extends the following major dimensions of meta-design: (1) It exploits the contributions of social media and web 2.0 as innovative information technologies; (2) It facilitates the shift from consumer cultures to cultures of participation; (3) It fosters social creativity by harnessing contributions that occur in cultures of participation; (4) It empowers end-users to be active designers involved in creating situated solutions. In a world where change is the norm, meta-design is a necessity rather than a luxury because it is impossible to design software systems at design time for problems that occur only at use time. The co-evolution of systems and users\u2bc social practices pursued in this thesis requires a software environment that can evolve and be tailored continuously. End-user development explores tools and methods to support end users who tailor software artifacts. However, it addresses this objective primarily from a technical perspective and focuses mainly on tailorability. This thesis, centered on meta-design, extends end-user development by creating social conditions and design processes for broad participation in design activities both at design time and at use time. It builds on previous research into meta- design that has provided a strategic overview of design opportunities and principles. And it addresses some shortcomings of meta-design, such as the lack of guidelines for building concrete meta-design environments that can be assessed by empirical evaluation. Given the goal of this research, to explore meta-design approaches for cultivating and supporting collaborative design, the overarching research question guiding this work is: How do we provide a socio-technical environment to bring multidisciplinary design communities together to foster creativity, collaboration, and design evolution? 8 To answer this question, my research was carried out through four different phases: (1) synthesizing concepts, models, and theories; (2) framing conceptual models; (3) developing several systems in specific application areas; and (4) conducting empirical evaluation studies. The main contributions of this research are: \uf0a7 The Hive-Mind Space model, a meta-design framework derived from the \u201csoftware shaping workshop\u201d methodology and that integrates the \u201cseeding, evolutionary growth, reseeding\u201d model. The bottom-up approach inherent in this framework breaks down static social structures so as to support richer ecologies of participation. It provides the means for structuring communication and appropriation. The model\u2bcs open mediation mechanism tackles unanticipated communication gaps among different design communities. \uf0a7 MikiWiki, a structured programmable wiki I developed to demonstrate how the hive-mind space model can be implemented as a practical platform that benefits users and how its features and values can be specified so as to be empirically observable and assessable; \uf0a7 Empirical insights, such as those based on applying MikiWiki to different collaborative design studies, provide evidence that different phases of meta-design represent different modes rather than discrete levels