- KonferenzbeitragVisual Stability in Dynamic Graph Drawings(i-com: Vol. 14, No. 3, 2015) Lezama, Alfredo Ramos; Chounta, Irene-Angelica; Göhnert, Tilman; Hoppe, H. Ulrich; Ziegler, JürgenIn graph visualizations, dynamic networks are a special challenge. A typical approach is visualizing the network at several points in time. Drawing these individual time slices often leads to changes in the layout that distract viewers from important information about individual nodes. In this article, we present a mathematical model to quantify the visual stability of dynamic graph drawings. The model takes into account structural and layout-oriented characteristics of the graphs. In order to validate the model, we conducted a study using questionnaires and an eye-tracking device. The participants were asked to track nodes in a dynamic network with three different methods. Then, we compared these methods based on the proposed model, user feedback (questionnaires) and behavioral data (eye-tracking). The results suggest that dynamic graph drawings which assign a fixed position on the canvas to every actor in the network improve the efficiency of the visual search. Nonetheless, more time is required to process the image. In contrast to that, those dynamic graph drawings with a constant shape or with a minimal number of changes require less time to process the image but lose efficiency of visual search.
- KonferenzbeitragA Generic Approach for Assessing Compatibility Between Task Descriptions and Interactive Systems: Application to the Effectiveness of a Flight Control Unit(i-com: Vol. 14, No. 3, 2015) Fayollas, Camille; Martinie, Célia; Navarre, David; Palanque, Philippe; Ziegler, JürgenTask models are a very powerful artefact describing users’ goals and users’ activities and contain numerous information extremely useful for designing usable interactive applications. Indeed, task models is one of the very few means for ensuring effectiveness of the application i. e. that the application allows users to reach their goals and perform their tasks. This paper presents a tool-supported framework for exploiting task models throughout the development process and even when the interactive application is deployed and used. To this end, we introduce a framework for connecting task models to an existing, executable, interactive application. The main contribution of the paper lies in the definition of a systematic correspondence between the user interface elements of the interactive application and the low level tasks in the task model. Depending on the fact that the code of the application is available or not, the fact that the application has been prepared at programming time for such integration or not, we propose different alternatives to perform such correspondence (in a toolsupported way). This task-application integration allows the exploitation of task models at run time bringing in the benefits listed above to any interactive application. The approach, the tools and the integration are presented on a case study of a Flight Control Unit (FCU) used in aircraft cockpits. This paper extends the article entitled ‘A Generic Tool-Supported Framework for Coupling Task Models and Interactive Applications’ which have been presented at the 7 ACM SIGCHI Symposium on Engineering Interactive Computing Systems (EICS 2015). In this expanded version, the detailed description of the correspondence between annotations in the program of the interactive application and interactive tasks in the task models has been added. The complete version of the case study has also been integrated so that the application of each step of the proposed validation process is presented.
- KonferenzbeitragGenerating Interactive Prototypes from Query Annotated Discourse Models(i-com: Vol. 14, No. 3, 2015) Kis, Filip; Bogdan, Cristian; Ziegler, JürgenModel Based User Interface Development offers the possibility to design User Interfaces without being concerned about the underlying implementation. This is achieved by devising models at a high level of abstraction, thus creating the potential for involving users or domain experts to achieve a user-centered design process. Obtaining a running interactive application from such models usually requires several model transformations. One of the current problems is that while a user interface is generated after these transformations, other parts of the interactive system such as the application logic need to pre-exist or they must be written manually before the interface can be tested in a realistic scenario. This leaves the domain experts dependent on programmers and increases the time between iterations. In this paper we work with Query Annotations, which were previously used only for modeling at low levels and for generating fully functional interfaces, and we aim to generalize them for the high-level modeling approach called Discourse Modeling. The direct expected benefit of this generalization is the possibility to generate complete, readily testable interactive prototypes, rather than just their user interfaces. In addition, Query Annotations can serve as the mapping between the various levels of abstraction and bring to the domain experts a better understanding of the transformation process, as well as the possibility to modify the interfaces and models directly.
- TextdokumentTrust in Cloud Computing: Pro and Contra from the User’s Point of View(i-com: Vol. 14, No. 3, 2015) Backhaus, Nils; Thüring, Manfred; Ziegler, JürgenCloud computing seems to solve many problems of conventional data processing. Due to the flexibility, mobility, and cost savings, users can customize their computing power more efficiently. However, there are also disadvantages. Users in part lose control over their data, e. g. they do not know where, how and under what circumstances their data is stored and processed, or who has access to their data. We describe the benefits and risks of cloud services and their impact on the acceptance and use on the (end-) users. We conclude that trust in cloud computing is a key factor that mitigates risks and can make the use of cloud computing services more effective.
- KonferenzbeitragVerification of Plastic Interactive Systems(i-com: Vol. 14, No. 3, 2015) Oliveira, Raquel; Dupuy-Chessa, Sophie; Calvary, Gaëlle; Ziegler, JürgenInteractive systems have largely evolved over the past years. Nowadays, different users can interact with systems on different devices and in different environments. The user interfaces (UIs) are expected to cope with such variety. Plastic UIs have the capacity to adapt to changes in their context of use while preserving usability. Such capability enhances UIs, however, it adds complexity on them. We propose an approach to verifying interactive systems considering this adaptation capability of the UIs. The approach applies two formal techniques: model checking, to the verification of properties over the system model, and equivalence checking, to compare different versions of a UI, thereby identifying different levels of UI equivalence. We apply the approach to a case study in the nuclear power plant domain in which several UI are analyzed, properties are verified, and the level of equivalence between them is demonstrated.
- editorialEditorial(i-com: Vol. 14, No. 3, 2015) Ziegler, Jürgen; Ziegler, Jürgen
- ZeitschriftenartikelThe Power of Freeletics(i-com: Vol. 14, No. 3, 2015) Franze, Christina; Funk, Lena; Strasser, Lisa; Diefenbach, Sarah; Ziegler, JürgenThe present article explores potential success factors of sports mobile apps by the example of Freeletics. Our analysis followed a two-sided approach: On the one hand, Freeletics is discussed in light of existing research and theory, with a focus on psychology, motivation theory and behavior change. On the other hand, we present a survey among 113 Freeletics users with interesting implications for app design. The analysis reveals that Freeletics actually makes use of a number of aspects and psychological mechanisms that previous research identified as important for physical activity apps and behavior change in general. Altogether, the present case highlights the importance to integrate psychological knowledge in technology design.
- ZeitschriftenartikelMensch und Computer 2015(i-com: Vol. 14, No. 3, 2015) Schmidt, Albrecht; Ziegler, Jürgen