Gerhard Austaller’s research while affiliated with Technical University of Darmstadt and other places

To support users in performing their tasks, applications need a better understanding of the current situation they are being used in. This chapter gives an overview of how knowledge of the current context, that is, information characterizing the situation, can be represented and how this knowledge can be used for enhancing applications. We discuss what is actually meant by “context” and “context-aware” applications. Further, we describe what has to be considered when building a context-aware application. We thereby focus on the representation of context information and how to deal with its unreliable nature. This chapter should sensitize the reader to the difficulties of using context information and give guidelines on how to build an application that benefits from knowing its current context.

To support users in performing their tasks, applications need a better understanding of the current situation they are being used in. This chapter gives an overview of how knowledge of the current context, that is, information characterizing the situation, can be represented and how this knowledge can be used for enhancing applications. We discuss what is actually meant by "context" and "context-aware" applications. Further, we describe what has to be considered when building a context-aware application. We thereby focus on the representation of context information and how to deal with its unreliable nature. This chapter should sensitize the reader to the difficulties of using context information and give guidelines on how to build an application that benefits from knowing its current context.

The chapter "Ubiquitous Services and Business Processes" discussed the benefits for real time enter-prises of service oriented architectures (SOA) in terms of reusability and flexibility. Web services are one incarnation of SOA. This chapter gives a brief introduction to SOA. It discusses the attributes that define SOA, the roles of the participants in a service oriented environment. The essence of SOA is that clients use services offered by a service provider to get a task done. For the moment we simplify service to "a software component with network connection". Services are offered with a description at wellknown "places" (also called registries, repositories), where clients choose services according to their needs. The chapter discusses several approaches to describe services and to look for them. Moreover, some well-known systems, and also current research, are discussed.

One of the main challenges in ubiquitous computing is mak- ing users interact with computing appliances in an easy and natural manner. In this paper we discuss how to turn or- dinary devices into Smart Products that are more intuitive to use and are self-explanatory. We present a general archi- tecture and a distributed runtime environment for building such Smart Products and discuss a number of user inter- action issues. As an example, we describe our smart coee machine and its validation through systematic user testing.

We took a standard off-the-shelf espresso machine and integrated a microcontroller, an RFID-reader, and a Bluetooth module. We can control the machine from a computer or a cellphone using these extensions. With the RFID-reader, the machine can automatically detect a cup being inserted; it is also possible to distinguish between cups. We have equipped the cups in our group with suitable RFID-tags. Coffee cups are shared, therefore users associate cups with them by using their personal, electronic doorkey. This action personalizes a cup with a user's preferences. Before cups are put into the dishwasher, they are swiped over a second RFID-reader to remove the user association. By default, cups stay personalized for a predefined time, the corresponding lease is extended every time the cup is used.

Ubiquitous and mobile web applications are typically very autonomous in nature, because they rely on additional information about the user’s context. In this paper we present a general context model for including context information into ubiquitous and mobile web applications. Our model is based on layers, which cover the path from context sources to the application level, including all intermediate filtering and context fusion. As an example, we present a context-aware calendar application built according to our context model.

Ubiquitous and mobile web applications are typically very autonomous in nature, because they rely on additional information about the user's context. In this paper we present a general context model for including context information into ubiquitous and mobile web applications. Our model is based on layers, which cover the path from context sources to the application level, including all intermediate filtering and context fusion. As an example, we present a context-aware calendar application built according to our context model.

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.