Volker Gruhn

Gestural interaction on the steering wheel: reducing the visual demand

Cars offer an increasing number of infotainment systems as well as comfort functions that can be controlled by the driver. In our research, we investigate new interaction techniques that aim to make it easier to interact with these systems while driving. We suggest utilizing the steering wheel as an additional interaction surface. In this paper, we present two user studies conducted with a working prototype of a multi-touch steering wheel. In the first, we developed a user-defined steering wheel gesture set, and in the second, we applied the identified gestures and compared their application to conventional user interaction with infotainment systems in terms of driver distraction. The main outcome was that drivers visual demand is reduced significantly by using gestural interaction on the multi-touch steering wheel.

Exploring the benefits of the combination of a software architecture analysis and a usability evaluation of a mobile application

Designing easy to use mobile applications is a difficult task. In order to optimize the development of a usable mobile application, it is necessary to consider the mobile usage context for the design and the evaluation of the user-system interaction of a mobile application. In our research we designed a method that aligns the inspection method Software ArchitecTure analysis of Usability Requirements realizatioN SATURN and a mobile usability evaluation in the form of a user test. We propose to use mobile context factors and thus requirements as a common basis for both inspection and user test. After conducting both analysis and user test, the results described as usability problems are mapped and discussed. The mobile context factors identified define and describe the usage context of a mobile application. We exemplify and apply our approach in a case study. This allows us to show how our method can be used to identify more usability problems than with each method separately. Additionally, we could confirm the validity and identified the severity of usability problems found by both methods. Our work presents how a combination of both methods allows to address usability issues in a more holistic way. We argue that the increased quantity and quality of results can lead to a reduction of the number of iterations required in early stages of an iterative software development process.

Seeing the forest and the trees: focusing team interaction on value and effort drivers

Large-scale information system development is often plagued by defects and deadline overruns that can be traced to insufficient communication within the project team, particularly between stakeholders from the business, technical and management side. Although agile process models put a strong emphasis on team communication, they provide only little support for focusing the communication on the most relevant issues. We therefore introduce the concept of so-called interaction rooms, where teams work with a pragmatic combination of model sketches and annotations to foster understanding of the system and its business domain, to reveal risks and uncertainties, and discuss those system aspects that are most critical for project success.

A model-based approach to test automation for context-aware mobile applications

Current testing tools for mobile applications do not provide sufficient support for context-aware application testing. In addition to regular input vectors (e.g. touch events, text entry) context parameters must be considered (e.g. accelerometer data interpreted as shake gestures, GPS location data, etc.). A multitude of possible application faults resulting from these additional context parameters requires an appropriately selected set of test cases. In this paper, we propose a model-based approach to improve the testing of context-aware mobile applications by deducing test cases from design-time system models. Using a custom-built version of the calabash-android testing framework enhanced by an arbitrary context parameter facility, our approach to test case generation and automated execution is validated on a context-aware mobile application.

Reducing complexity using an interaction room: an experience report

Large-scale information system evolution projects often place high demands on both business and technical stakeholders cognitive and communication skills. Especially if the need for evolution is not confined to a particular feature, but affects the whole value chain, finding dependencies and interrelationships between processes and components is challenging as it requires cross-departmental understanding. These issues can be even more challenging for management stakeholders who need to make high-level and far-reaching decisions on implementation strategies despite not being deeply involved in the technical details. One of the main problems in such projects is that the stakeholders who have expert knowledge typically have only little methodical experience, while the method experts lack the business experience. In this paper, we report on experiences and lessons from a large systems evolution project in a German insurance company, where we applied a new approach -- the so-called Interaction Room -- to improve stakeholders understanding of the projects risks and dependencies in a pragmatic way, without overwhelming them with a heavyweight analysis method.

Detecting Common Errors in Event-Driven Process Chains by Label Analysis

In this article, we discuss several classes of error patterns that can frequently be found in Event-Driven Process Chains (EPC). Instances of these patterns can be detected by using a pattern-matching approach: The model is translated into a set of Prolog rules and potential modelling problems are located by querying the Prolog fact base for certain problem patterns. In particular, this article presents patterns for problems that can be detected by analysing the labels of events and functions in EPCs. To make reasoning about the contents of the labels possible, the labels are transformed into a normal form. By taking synonyms, antonyms and negating words (no, not) into account, we locate labels that contradict each other. This leads to the detection of some classes of errors like modelling of an event and its negation occurring at the same time. Our method has been applied to 1253 EPC models in German language. We have been able to detect a large number of errors in those models that remain undetected using traditional approaches for EPC validation.

Patterns for tearing down contribution barriers to FLOSS projects

The success of a “Free, Libre and Open Source Software” (FLOSS) project depends on its ability to attract new developers. However, before prospective developers can contribute their first patch, they have to overcome the contribution barriers of the FLOSS project. This paper presents two patterns. Each pattern identifies a possible problem in the contribution processes of FLOSS projects and shows a practice to alleviate this problem. The first pattern helps prospective developers compile the FLOSS projects source code and build an executable application. The second pattern encourages prospective developers to submit their modifications back to the FLOSS project and at the same time fosters integration of these modifications into the main development branch of the FLOSS project.

An exploratory study of contribution barriers experienced by newcomers to open source software projects

Contributing to a Free, Libre and Open Source Software (FLOSS) project is not a trivial task even for experienced developers: Beyond the effort required for understanding and editing a projects source code for ones own purposes, submitting the changes back to the community requires additional motivation, time, and social and technical effort. Although several surveys have examined the dynamics driving FLOSS contributors, most focus either on the motivations of core developers or indicators of potential long-term commitment, i.e. the small but quite involved and visible minority at the core of a project. Our survey in contrast examines the experiences of the much larger, but nearly invisible group of developers who are just making and submitting their first patch, and identifies barriers that hinder or even prevent them from making a valuable contribution.

Automating UI tests for mobile applications with formal gesture descriptions

Touch- and gesture-based interfaces are common in applications for mobile devices. By evolving into mass market products, smartphones and tablets created an increased need for specialized software engineering methods. To ensure high quality applications, constant and efficient testing is crucial in software development. However, testing mobile applications is still cumbersome, time-consuming and error-prone. One reason is the devices focus on touch-based interaction - gestures cannot be easily incorporated into automated application tests. We present an extension to the popular Calabash testing framework solving this problem by allowing to describe gestures with a formal language in tests scripts.

Value-Based Migration of Legacy Data Structures

The maintenance and evolution of legacy applications and legacy data structures poses a significant challenge for many organizations that rely on large-scale information systems, e.g. in the financial services domain: Not only is the budget for modernizations that add more technical stability and flexibility than business functionality often slim, but it is also difficult to understand and design the best migration strategies for a large and organically grown system landscape. We report on the experiences from a migration project at a large bank that pursued a value-based approach, in which migration efforts were first focused on a small set of business processes that were identified as most crucial for the enterprise. The migration strategies developed and validated in this pilot phase could later be successfully applied to the larger system landscape.