Thomas Springer

Pervasive social context: Taxonomy and survey

As pervasive computing meets social networks, there is a fast growing research field called pervasive social computing. Applications in this area exploit the richness of information arising out of people using sensor-equipped pervasive devices in their everyday life combined with intense use of different social networking services. We call this set of information pervasive social context. We provide a taxonomy to classify pervasive social context along the dimensions space, time, people, and information source (STiPI) as well as commenting on the type and reason for creating such context. A survey of recent research shows the applicability and usefulness of the taxonomy in classifying and assessing applications and systems in the area of pervasive social computing. Finally, we present some research challenges in this area and illustrate how they affect the systems being surveyed.

Exploiting single-user web applications for shared editing: a generic transformation approach

In the light of the Web 2.0 movement, web-based collaboration tools such as Google Docs have become mainstream and in the meantime serve millions of users. Apart from established collaborative web applications, numerous web editors lack multi-user support even though they are suitable for collaborative work. Enhancing these single-user editors with shared editing capabilities is a costly endeavor since the implementation of a collaboration infrastructure (accommodating conflict resolution, document synchronization, etc.) is required. In this paper, we present a generic transformation approach capable of converting single-user web editors into multi-user editors. Since our approach only requires the configuration of a generic collaboration infrastructure (GCI), the effort to inject shared editing support is significantly reduced in contrast to conventional implementation approaches neglecting reuse. We also report on experimental results of a user study showing that converted editors meet user requirements with respect to software and collaboration qualities. Moreover, we define the characteristics that editors must adhere to in order to leverage the GCI.

Quality Attributes in Mobile Web Application Development

The paper deals with quality attributes for mobile web applications. It describes typical challenges when developing mobile web applications and relates the challenges to the ISO 9126 quality attributes. The quality attributes are summarized to an ISO model that is focusing on the most important quality attributes for the quality assurance of mobile web applications. Finally, the paper proposes that applying formal quality assurance methods during the development of mobile web applications may solve some of the challenges in mobile web application development.

Ad-Hoc Usage of Web Services with Dynvoker

While web services are often targeted at machine-to-machine communication, they are also increasingly used directly in the interactions between humans and machines. Instead of developing specialised client applications for the invocation of these services, a generic human-driven ad-hoc usage is beneficial in many scenarios, including rapid service testing and dynamic inclusion of services as plugins into applications. We argue for the need for such a usage and extract requirements for generic web service clients. We then present a few selected use cases and introduce the Dynvoker client which already passes the majority of evaluation criteria. With its technical capabilities and open and vivid development, we consider it the most suitable and flexible generic client available and therefore highlight its role as a central component in a user-centric web service research project.

Employing description logics in Ambient Intelligence for modeling and reasoning about complex situations

Ambient Intelligence systems need to represent information about their environment and recognize relevant situations to perform appropriate actions proactively and autonomously. The context information gathered by these systems comes with imperfections such as incompleteness or incorrectness. These characteristics need to be handled gracefully by the Ambient Intelligence system. Moreover, the represented information must allow for a fast and reliable recognition of the current situation. To solve these problems we propose a method for situation modeling using the Description Logics based ontology language OWL DL and a framework for employing Description Logics reasoning services to recognize the current situation based on context. The benefits from the approach are manifold: the semantics of Description Logics allow for graceful handling of incomplete knowledge. The well-investigated reasoning services do not only allow recognizing the current situation, but also can add to the reliability of the overall system. Moreover optimized reasoning systems are freely available and ready to use. We underpin the feasibility of our approach by providing a case study based on a smart home application conducting an evaluation of different Description Logics reasoners with respect to our application ontology as well as a discussion of Description Logics systems in Ambient Intelligence.

A service infrastructure for the Internet of Things based on XMPP

Following the vision of an Internet of Things (IoT) real world objects are integrated into the Internet to provide data as sensors and to manipulate the real world as actors. While current IoT approaches focus on the integration of things based on service technologies, scenarios in domains like smart cities, automotive or crisis management require service platforms involving real world objects, backend-systems and mobile devices. In this paper we introduce a service platform based on the Extensible Messaging and Presence Protocol (XMPP) for the development and provision of services for such pervasive infrastructures. We argue for XMPP as protocol for unified, real-time communication and introduce the major concepts of our platform. Based on two case studies we demonstrate real-time capabilities of XMPP for remote robot control and service development in the e-mobility domain.

Defining Situated Social Context for pervasive social computing

There is a multitude of systems in the area of mobile and pervasive social computing providing and using social context for pervasive interaction between persons. Currently, it is hard to distinguish the different approaches as there is no appropriate taxonomy available yet. In this paper we introduce the STIP taxonomy to define social context in the area of social computing and further propose to use the term Situated Social Context for a more focused subset of social context for pervasive social computing. We elaborate the taxonomy with a small survey of mobile social networking systems and discuss future research challenges.

A service-oriented approach for increasing flexibility in manufacturing

Manufacturing environments are characterized by a multitude of heterogeneous devices, networks, specific protocols and applications. Therefore, static structures, close coupling and vendor-specific solutions have been established over decades. To increase flexibility and interoperability we introduce a service-oriented middleware approach in form of an integration layer between shop-floor equipment and enterprise applications. The integration layer addresses the actual capabilities and data flows on the field and control layer individually. It offers core services that are applicable in several manufacturing domains. We describe a detailed case study to discuss pros and cons of a SOA approach in manufacturing systems and to show the feasibility of our approach.

Service-based development of mobile real-time collaboration applications for Social Networks

Social Networks will unfold their full potential when connected people are enabled to collaborate - any time, appropriate to the current location, activity and computing environment. However, development of collaborative applications in pervasive environments is still a big challenge. In this paper we present a service-oriented approach for the development of collaborative applications on top of social networks. It consists of a conceptual platform providing a set of generic services for real-time collaboration and the integration of existing social networks. In an experimental evaluation we implemented the conceptual platform for Android devices using the Extensible Messaging and Presence Protocol (XMPP) family together with a set of reusable services for Facebook integration, user location and proximity detection, media sharing, and collaborative editing. We developed several case study applications by composing generic collaboration services to demonstrate the feasibility and value of the approach.

Context-Dependent Access Control for Contextual Information

Following Mark Weisers vision of ubiquitous computing and calm technology, computer systems should run in the background, preferably without the user noticing it at all. The gathering and disclosure of contextual information on the one hand enables the improvement of system behaviour towards a more autonomous and adaptive behaviour but on the other hand raises privacy issues by disclosing personal data. Thus, a major challenge in ubiquitous computing environments is achieving a good balance between convenience and control over personal data. In this paper we describe an access control mechanism for context data that enables the user to control his personal data in a convenient and non-intrusive way. The approach is based on existing role-based access control mechanisms but extends them as follows. Firstly, our approach is owner-centric, i.e. it is under control of each user, to whom his context is propagated throughout the system. Secondly, our approach does not only control the access to context data but also utilizes context information to simplify the management of these control mechanisms to make the handling of access control more convenient to the user. And thirdly, it introduces individual roles for each user and thus replaces the centrally defined role model of common role-based access control by distinct models for each user. We have validated our approach based on an extended instant messaging system called Adaptive Multimedia Messenger, providing varying buddy information dependent on the access permission of the requesting user