Andreas Hartl’s research while affiliated with Technical University of Darmstadt and other places

Using cell information for locating users in cellular networks is a common way to implement location based servers. However, implementations usually rely on infrastruc- ture on the provider's side like special lookup servers. We present a light-weight solution that communicates the cell information to Web services. Our software is event based and therefore well suited for pro-active location based services. While still requiring network specific data, it is provider independent and extensible easily.

Users in a ubiquitous computing world will interact with several devices simultaneously. This multi-device interaction paradigm presents significant challenges to both authoring and runtime application rendering. In this paper we present our work on spanning user interfaces across federated devices. Our first contribution is a single-authoring language for multi-device interfaces which allows authors to specify how their applications should be rendered. Our second contribution is a mechanism for selecting the appropriate devices and rendering the user interface on them.

Despite the large variety of mobile devices available today, none of them is without flaws: small devices like cell phones are very limited regarding interaction, while larger devices like laptops lack true mobility. We are investigating how both mobility and rich interaction can be achieved by federating small mobile devices with other interactive devices on demand. However, this raises the question how user interfaces can be authored if the target device is not static and known, but rather a changing set depending on user context. We approach this using device independent widgets, which are mapped to device specific widgets at runtime.

Ubiquitous computing focusing on users and tasks instead of devices and singular applications is an attractive vision for the future. Especially the idea of nomadic, mobile users poses new challenges on hardware and software. Mobile devices provide vastly different presentation capabilities and need to integrate into heterogeneous environments. Network bandwidth is far from being constant and services may be available only when online. This paper presents MUNDO, an infrastructure for ubiquitous computing that addresses these challenges. The infrastructure is intended to be non-monolithic with its parts supporting mobile computing using multi-modal user interfaces, mobile data delivery, and ad-hoc communication and networking.

This technical report introduces goals and early findings of a multi-year multi-party project MUNDO. MUNDO is a pool of services and enablers for mobile and ubiquitous computing. It emphasizes easy global evolutionary deployment as a migra- tion path for the Internet as a whole towards a nomadic computing economy. The no- madic users access the network via personal devices and associated public and private appliances. The network is liberated from common constraints such as central opera- tors and fixed home bases of users. It hosts services which are by themselves migrat- able and highly adaptive with respect to region and context-awareness, quality varia- tions, and terminal characteristics. Migration and adaptation may be realized by dif- ferent implementations of the same service. An underlying general cost model helps to mediate user desires and service offerings. A number of scenarios and correspond- ing MUNDO application pools are described in order to motivate the features and scope of MUNDO. We describe a "radio on steroids" application pool called DACAR in more detail. We outline the architecture of MUNDO and elaborate its system services.

Ubiquitous computing focusing on users and tasks instead of devices and singular applications is an attractive vision for the future. The idea of nomadic, mobile users in particular poses new challenges for hardware and software. Mobile devices provide vastly different presentation capabilities and need to integrate into heterogeneous environments. Network bandwidth is far from being constant and services may be available only when online. This paper presents MUNDO, an infrastructure for ubiquitous computing that addresses these challenges. The infrastructure is intended to be non-monolithic with its parts supporting mobile computing using multi-modal user interfaces, mobile data delivery, and ad-hoc communication and networking.

As the WWW goes wireless software engineers experience the challenge of developing WAP applications which respond to both the constraints and the opportunities of the wireless Web. The Gulliver project addresses the three pertinent questions prevailing among the WWW audience: i) How should and must WAP content differ from traditional Web content? ii) How does the development of WAP applications differ from Web applications? iii) How does a development environment for WAP applications look like?

This paper is structured as follows. Section 2 presents related work. Then, in Section 3 we describe the Gulliver platform and in particular Gulliver Beans. Next, Section 4 discusses the approach presented. We finish with a summary and conclusions.

This paper is structured as follows. Section 2 presents related work. Then, in Section 3 we describe the Gulliver platform and in particular Gulliver Beans. Next, Section 4 discusses the approach presented. We finish with a summary and conclusions

Abstract The ever increasing popularity of the Internet results in a growing number of users being connected to the World Wide Web with new types of devices ranging from PDAs to mobileph ones. However, existing content has not been designed with the benefits and limitations of these devices in mind and thus various approaches have been established to overcome this issue. Our approach strictly separates between content, presentation and behavior in order to be able to dynamically generate adapted and individualized content. Besides device information our prototype system takes other context data into account including location and user preferences. Our approach allows usto semi-automatically produce,content which isn ot only optimized for the target platform but also designed for the individual users and their specific needs.