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What are the most suitable interaction paradigms for navigational and informative tasks for pedestrians? Is there an influence of social and situational context on multimodal interaction? Our study takes a closer look at a multimodal system on a handheld device that was recently developed as a prototype for mobile navigation assistance. The system allows visitors of a city to navigate, to get information on sights, and to use and manipulate map information. In an outdoor evaluation, we studied the usability of such a system on site. The study yields insight about how multimodality can enhance the usability of hand-held devices with their future services.

The development of a tool for reconstructing UML sequence diagrams from executing Java programs is a challenging task. We implemented such a tool designed to analyze any kind of Java program. Its implementation relies heavily on several advanced features of the Java platform. Although there are a number of research projects in this area usually little information on implementation-related questions or the rationale behind implementation decisions is provided. In this paper we present a thorough study of technological options for the relevant concerns in such a system. The various options are explained and the tradeoffs involved are analyzed. We focus on practical aspects of data collection, data representation and meta-model, visualization, editing, and export concerns. Apart from analyzing the available options, we report our own experience in developing a prototype of such a tool in this study. It is of special interest to investigate systematically in what ways the Java platform facilitates (or hinders) the construction of the described reverse engineering tool.

Today component-and service-based technologies play a central role in many aspects of enterprise computing. However, although the technologies used to define, implement, and assemble components have improved significantly over recent years, techniques for verifying systems created from them have changed very little. The correctness and reliability of component-based systems are still usually checked using the traditional testing techniques that were in use before components and services became widespread, and the associated costs and overheads still remain high. This paper presents an approach that addresses this problem by making the system verification process more component-oriented. Based on the notion of built-in tests (BIT)-tests that are packaged and distributed with prefabricated, off-the-shelf components-the approach partially automates the testing process, thereby reducing the level of effort needed to establish the acceptability of the system. The approach consists of a method that defines how components should be written to support and make use of runtime tests, and a resource-aware infrastructure that arranges for tests to be executed when they have a minimal impact on the delivery of system services. After providing an introduction to the principles behind component-based verification and explaining the main features of the approach and its supporting infrastructure, we show by means of a case study how it can reduce system verification effort.