PROVIDING FUND UPDATES TO A STORED VALUE CARD

A payment processing system provides offline fund updates to a stored value card. The stored value card may be used to conduct transactions with a merchant using funds maintained on the stored value card. The payment processing system receives funds to supplement a stored value card when the stored value card does not have a communication connection with the payment processing system. After receiving the funds, the payment processing system identifies a set of merchants with which a user of the stored value card is likely to interact. The payment processing system transmits the fund update to the merchants. When the user employs the stored value card at a point of sale terminal associated with one of the identified merchants, the fund update is transmitted to the stored value card. The balance on the stored value card is updated accordingly

Engineering Multimedia-Aware Personalized Ubiquitous Services

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

A Focus on Location Context

This chapter adds an in-depth description of location context, because location is the most prominent context property and the associated tracking technology is increasingly deployed in industry. First, we motivate a number of application areas for this technology in industry, healthcare, tourism, and more. We first describe the different physical properties location sensors can measure and then the principles and algorithms to calculate the locations of mobile entities based on this sensor data. Several commercial location systems and research prototypes are described as implementation examples. Finally, with the help of location models, the raw location information is processed to derive higher-level information meaningful to application services

Event-Based and Publish/Subscribe Communication

Ubiquitous Computing assumes that users and their computing devices are highly mobile. Because it is unlikely that mobile networks will be equally available in the same quality everywhere, there may be varying levels of connectivity, ranging from full network availability through low-bandwidth connectiv- ity, to no connection at all. As a consequence, software components in the system cannot assume that the connections between them are static and always available. The event-based style is essential for ubiquitous computing, since it offers a good decoupling of the communicating entities in terms of space, time, and program flow. This chapter starts with an introduction to the different interaction models found in distributed systems. Next, a classification of publish/subscribe-systems is presented. We then describe a formal data and filter model that allows us to precisely define the semantics of event filters. Based on this model, we discuss different routing algorithms for the efficient distribution of event notifications in a network. Finally, a number of examples for publish/subscribe systems are presented