Sarah A. Douglas

A Meta-Study of Algorithm Visualization Effectiveness

Algorithm visualization (AV) technology graphically illustrates how algorithms work. Despite the intuitive appeal of the technology, it has failed to catch on in mainstream computer science education. Some have attributed this failure to the mixed results of experimental studies designed to substantiate AV technologys educational effectiveness. However, while several integrative reviews of AV technology have appeared, none has focused specifically on the softwares effectiveness by analyzing this body of experimental studies as a whole. In order to better understand the effectiveness of AV technology, we present a systematic meta-study of 24 experimental studies. We pursue two separate analyses: an analysis ofindependent variables , in which we tie each study to a particular guiding learning theory in an attempt to determine which guiding theory has had the most predictive success; and an analysis of dependent variables, which enables us to determine which measurement techniques have been most sensitive to the learning benefits of AV technology. Our most significant finding is that how students use AV technology has a greater impact on effectiveness than what AV technology shows them. Based on our findings, we formulate an agenda for future research into AV effectiveness.

Testing pointing device performance and user assessment with the ISO 9241, Part 9 standard

The IS0 9241, Part 9 Draft International Standard for testingcomputer pointing devices proposes an evaluation of performance andcomfort. In this paper we evaluate the scientific validity andpracticality of these dimensions for two pointing devices forlaptop computers, a finger-controlled isometric joystick and atouchpad. Using a between-subjects design, evaluation ofperformance using the measure of throughput was done forone-direction and multi-directional pointing and selecting. Resultsshow a significant difference in throughput for themulti-directional task, with the joystick 27% higher; results forthe one-direction task were non-significant. After the experiment,participants rated the device for comfort, including operation,fatigue, and usability. The questionnaire showed no overalldifference in the responses, and a significant statisticaldifference in only the question concerning force required tooperate the device - the joystick requiring slightly more force.The paper concludes with a discussion of problems in implementingthe IS0 standard and recommendations for improvement.

The Zebrafish Information Network (ZFIN): a resource for genetic, genomic and developmental research

The Zebrafish Information Network, ZFIN, is a WWW community resource of zebrafish genetic, genomic and developmental research information (http://zfin.org). ZFIN provides an anatomical atlas and dictionary, developmental staging criteria, research methods, pathology information and a link to the ZFIN relational database (http://zfin. org/ZFIN/). The database, built on a relational, object-oriented model, provides integrated information about mutants, genes, genetic markers, mapping panels, publications and contact information for the zebrafish research community. The database is populated with curated published data, user submitted data and large dataset uploads. A broad range of data types including text, images, graphical representations and genetic maps supports the data. ZFIN incorporates links to other genomic resources that provide sequence and ortholog data. Zebrafish nomenclature guidelines and an automated registration mechanism for new names are provided. Extensive usability testing has resulted in an easy to learn and use forms interface with complex searching capabilities.

Teaching HCI Design With the Studio Approach

The studio-based method of teaching has been used for almost 100 years to teach product and architecture design. With ever increasing pressure on HCI to teach competence in designing interactive objects, new ways of teaching need to be explored. This article begins with a review of the studio-based teaching concept and how it has been used in architecture, science/engineering, and computer science education. We then present and discuss the evaluation of an HCI design studio course which we created and taught in spring 2002 in the Computer and Information Science Department of the University of Oregon. This course was based on our observations and study of studio courses in the School of Architecture. Finally, we review general issues about studio teaching including the promises and challenges that it presents to widespread acceptance in the computer science curriculum.

Learning text editor semantics by analogy

This paper presents a cognitive model for one aspect of how novices learn text editors—the acquisition of procedural skill by problem solving in problem spaces and the use of analogy for building a representation of the semantics of text-editor commands (which we call operators). Protocol data of computer-naive subjects learning the EMACS text editor suggests that they use their knowledge of typewriting to decide which commands to use in performing editing tasks. We propose a formal method of analysis that compares operators in two problem spaces and generates misconceptions. The comparison of these predicted misconceptions with verbal comments, error data, and task difficulty lends support to this analysis.

The ergonomics of computer pointing devices

Will reading habit influence your life? Many say yes. Reading the ergonomics of computer pointing devices is a good habit; you can develop this habit to be such interesting way. Yeah, reading habit will not only make you have any favourite activity. It will be one of guidance of your life. When reading has become a habit, you will not make it as disturbing activities or as boring activity. You can gain many benefits and importances of reading.

Differences in movement microstructure of the mouse and the finger-controlled isometric joystick

This paper describes a study comparing the movement characteristics of the mouse and the velocity-control isometric joystick. These characteristics are called the microstructure of movement. The comparison found random variations in the velocity of the isometric joystick that make it hard to control. The study shows that the microstructure of movement can explain differences in performance among devices.

Application-based evaluation of haptic interfaces

A taxonomy of haptic modes is proposed as a basis for evaluating haptic interfaces. Haptic modes are defined as distinct styles of using haptic perception for purposeful activity. An evaluation method that exercises a single haptic mode tests the hardware and software of the interface on a task that has a clear relationship to actual applications. To demonstrate this approach to evaluation, the mode of geometric perception was evaluated for a point force device. Twelve observers performed a shape recognition task using a PHANToM display. The task proved difficult, with a mean recognition time of 22 s. This class of devices does not appear to support adequate performance for applications that require geometric perception. The paper concludes with possible extensions to both the shape recognition protocol and the taxonomy of modes.

Low Fidelity Algorithm Visualization

Computer science educators have traditionally used algorithm visualization (AV) software to create graphical representations of algorithms for use as visual aids in lectures, or as the basis for interactive labs. Typically, such visualizations are high-fidelity in the sense that (a) they depict the target algorithm for arbitrary input, and (b) they tend to have the polished look of textbook figures. In contrast, low-fidelity visualizations illustrate the target algorithm for a few, carefully chosen input data sets, and tend to have a sketched, unpolished appearance. Drawing on ethnographic field studies of a junior-level undergraduate algorithms course, we motivate the use of low-fidelity AV technology as the basis for an alternative learning paradigm in which students construct their own visualizations, and then present those visualizations to their instructor and peers for feedback and discussion. To explore the design space of low-fidelity AV technology, we present SALSA (Spatial ALgorithmic Language for StoryboArding) and ALVIS (ALgorithmVI sualization Storyboarder), a prototype end-user language and system firmly rooted in empirical studies in which students constructed and presented visualizations made out of simple art supplies. Our prototype end-user language and system pioneer a novel technique for programming of visualizations based on spatial relations, and a novel presentation interface that supports human discussions about algorithms by enabling reverse execution and dynamic mark-up and modification. Moreover, the prototype provides an ideal foundation for what we see as the algorithms classroom of the future: the interactive ‘algorithms studio’.

Model and representation: the effect of visual feedback on human performance in a color picker interface

User interfaces for color selection consist of a visible screen representation, an input method, and the underlying conceptual organization of the color model. We report a two-way factorial, between-subjects variable experiment that tested the effect of high and low visual feedback interfaces on speed and accuracy of color matching for RGB and HSV color models. The only significant effect was improved accuracy due to increased visual feedback. Using color groups as a within-subjects variable, we found differences in performance of both speed and accuracy. We recommend that experimental tests adopt a color test set that does not show bias toward a particular model, but is based instead on a range of colors that would be most likely matched in practice by people using color selection software. We recomment the Macbeth Color Checker naturals, primaries, and grays. As a follow-up study, a qualitative case analysis of the way users navigated through the color space indicates that feedback helps users with limited knowledge of the model, allowing them to refine their match to a higher degree of accuracy. Users with very little or a lot of knowledge of the color model do not appear to be aided by increased feedback. In conclusion, we suggest that visual feedback and design of the interface may be a more important factor in improving the usability of a color selection interface than the particular color model used.