Published papers (included in the dissertation) Published papers (included in the dissertation)
Janne Kaipala and Jouni Huotari, in proceedings of Information Systems Development - ISD'98 conference, Bled, Slovenia
The complexity of information systems has resulted in more sophisticated CASE tools which integrate multifaceted design information using metamodeling and hypertext technologies. A designer can use this vast amount of tightly coupled information efficiently only if it is presented based on his needs and cognitive capabilities. In this paper we discuss how representations in CASE can be improved using advanced visualisation techniques.
Jouni Huotari, in proceedings of STep'98 - Human and Artificial Information Processing, Jyv�skyl�, Finland
The visualisation and conceptualisation of complex information spaces is considered important in many studies. While there is a growing number of new users of complex information systems, only seldom user's cognitive characteristics are really taken into account. Now, when computers are capable to provide advanced visualisation and hypermedia information, their use should be carefully studied and appropriate solutions implemented. In this paper we suggest how user's cognitive capabilities and usability issues should be considered in visual representations. The focus is on supporting user's understanding of complex information spaces by advanced visualisation techniques. We show that although there are several novel information visualisation applications and research prototypes available, none of them meets all the suggested evaluation criteria.
Jouni Huotari and Janne Kaipala, in IRIS 22 (1999) "Enterprise Architectures for Virtual Organisations", edited by Timo K�k�l�, Keurusselk�, Finland, Jyv�skyl� University Printing House
This paper summarizes results of scientific work within a field of Human-Computer Interaction (HCI) focusing on cognitive aspects. Our review analyzes and synthesizes the main contributions and takes a critical view for the methods used. We also conducted a survey on some main IS research articles how cognitive aspects are considered and what methods are used. Despite a trend of applying cognitive task analysis and other user-centered system design methods, issues of human cognition and human information processing still need more attention in the IS research.
Jouni Huotari and Marketta Niemel�, in IV'02 (2002) Sixth International Conference on Information Visualisation.
Current CASE tools lack efficient techniques to visualise information system (IS) design repository. One important aspect in visualising graphical IS models is to preserve structure, which can have semantic value. Another key issue is to provide both focus and context in order to understand how detailed information relates to other design elements. The third aspect to consider is to trace between diagrams and other design documents. Our VRML implementation integrates different types of diagrams in one whole. We applied elision technique for decomposition of data flow diagrams (DFD) and added visible lines to link parts of DFD to entity-relation diagrams. In our laboratory experiment, we collected users' subjective opinions and performance in information search tasks. Based on the promising results, we give suggestions for further exploration.
Jouni Huotari, Kalle Lyytinen, and Marketta Niemel�, in ACM Transactions on Computer-Human Interaction (TOCHI), Volume 10 , Issue 4 (December 2003) .
The following extended abstract was published in interactions,
Vol 10 (6), 9-10, November 2003.
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We studied the impact of large screens and of two promising visual integration techniques, elision and connecting lines, which can decrease the cognitive efforts of designers to read diagrams. We conducted a laboratory experiment using 84 computer-science students to investigate the impact of these techniques on the accuracy of the subjects� search and recall with entity-relationship diagrams and data flow diagrams. Both vertical and horizontal searches were conducted on a moderately complex information system model that consists of multiple diagrams. We also examined the subjects� spatial visualization abilities as a possible covariant for observed search performance. The visual integration techniques significantly reduced errors in both the search and the recall of diagrams, especially for individuals with low spatial visualization ability.
The results show that paying attention to the visual aspects of diagrams can improve their readability, especially with subjects who have low spatial visualization ability. We believe that the findings are important because issues on dataflow and entity-relationship diagrams can be transferred to any diagramming techniques that share similar features. One promising target is the improvement of Unified Modeling Language (UML), which includes complex relationships between diagrams. For practicing designers, our study suggests several ways in which error rates in design activities can be decreased. They suggest that the use of larger screens is consistently better than the use of small separate diagrams, thus lending support to the use of techniques such as Joint Application Development (JAD). Moreover, the impact of such large screens can be amplified by using advanced visualization techniques. Finally, we should approach the use of 3-D representations with caution in abstract domains until we can create effective ways to map semantics into 3-D space and rendering techniques. Our message to Computer-Aided Software Engineering (CASE) tool vendors is that they should seriously consider providing improved linking and visualization support in CASE tools that help search design repositories through customizable, interactive task windows. The tools should also provide adequate intelligence to automatically arrange large layouts that reduce the number of crossing lines or hide links. Similar integration and dispersion problems also naturally exist in other domains. Therefore, in the end, all users that rely on visual representations in their cognitive tasks would benefit from better tools with advanced visualization techniques.
Overall, this is one of the first experimental studies that evaluates the impact of visual integrations methods, which help IS designers and other stakeholders understand complex graphical specifications. This is surprising given that these representations have been deployed widely for 20 years in IS design tasks. The cognitive foundations of searching information across multiple diagrams and representations are largely unstudied. This experiment is one step toward developing and deploying design tools that address better the cognitive needs of IS designers through more powerful diagram displays.
Jouni Huotari, in Proceedings of the Second International Conference on Coordinated and Multiple Views in Exploratory Visualization - CMV 2004
Information system models often consist of multiple views and semi-structured diagrams, which form both a hierarchical and a network structure. These models should be reviewed in order to find possible faults as early as possible in the development process. A conventional CASE tool shows diagrams in separate windows without any visual cues about how diagrams relate to each other. This might result in design errors, omissions, and inconsistencies. We introduce problem areas and potential solutions on how to visualize interrelationships between UML diagrams. Our research prototype enables exploration within the model, utilizes intelligent zooming (hides and shows details automatically), and shows how diagrams and objects within them could be related to each other by using visual cues.
Suomenkielinen matkaraportti
Jouni Huotari, Academic dissertation, February 2005. Jyv�skyl� Studies in Computing, 52. Introduction: (PDF-version available) (392 KB).
Graphical information system (IS) models comprise of several diagram types representing both static structure and dynamic behavior at many levels of detail. Critical design information is distributed across a collection of diagrams, which share some common elements such as objects and their properties. The examination of multiple diagrams slows search performance and could result in reading errors that later cause omissions and inconsistencies. We need better methods and tools, which help understanding the �whole� model and how different parts relate to each other. Especially, during the reviewing process, reviewers need representations that help exploring the model and enable seeing inter-relationships between diagrams.
In this thesis, we examine visualization and cognitive aspects of representing design information. We start this by synthesizing the main contributions and research methods in the HCI field. Then we propose a framework for evaluating visualization tools. As a third step, we introduce initial findings and suggestions for using advanced visualization techniques in computer-aided software engineering (CASE) environments. Our first research prototype was used in a laboratory experiment, where we examined the impact of using a large screen, an elision technique, connecting lines, and three-dimensional visualization on readability and recall of a set of graphical IS models. Our second prototype is able to produce 3D UML diagrams, to examine the model, and to show how diagrams are related to each other.
We found out that visual integration techniques decrease the designers� cognitive efforts to read and integrate diagrams and significantly reduce errors in both search and recall tasks, especially with respect to individuals with low spatial visualization ability. The research results improve our understanding of how design information is represented. It helps understanding relationships between different types of diagrams and between different levels of detail. This conclusion is applicable to other domains, where information is scattered in various visual forms and levels of detail.