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ACM Transactions on Computer-Human Interaction 10

Editors:Jonathan Grudin
Standard No:ISSN 1073-0516
Links:Table of Contents
  1. TOCHI 2003 Volume 10 Issue 1
  2. TOCHI 2003 Volume 10 Issue 2
  3. TOCHI 2003 Volume 10 Issue 3
  4. TOCHI 2003 Volume 10 Issue 4

TOCHI 2003 Volume 10 Issue 1

Diagramming information structures using 3D perceptual primitives BIBAFull-Text 1-19
  Pourang Irani; Colin Ware
The class of diagrams known collectively as node-link diagrams are used extensively for many applications, including planning, communications networks, and computer software. The defining features of these diagrams are nodes, represented by a circle or rectangle connected by links usually represented by some form of line or arrow. We investigate the proposition that drawing three-dimensional shaded elements instead of using simple lines and outlines will result in diagrams that are easier to interpret. A set of guidelines for such diagrams is derived from perception theory and these collectively define the concept of the geon diagram. We also introduce a new substructure identification task for evaluating diagrams and use it to test the effectiveness of geon diagrams. The results from five experiments are reported. In the first three experiments geon diagrams are compared to Unified Modeling Language (UML) diagrams. The results show that substructures can be identified in geon diagrams with approximately half the errors and significantly faster. The results also show that geon diagrams can be recalled much more reliably than structurally equivalent UML diagrams. In the final two experiments geon diagrams are compared with diagrams having the same outline but not constructed with shaded solids. This is designed to specifically test the importance of using 3D shaded primitives. The results also show that substructures can be identified much more accurately with shaded components than with 2D outline equivalents and remembered more reliably. Implications for the design of diagrams are discussed.
The effects of information scent on visual search in the hyperbolic tree browser BIBAFull-Text 20-53
  Peter Pirolli; Stuart K. Card; Mija M. Van Der Wege
The Hyperbolic Tree is a focus + context information visualization that has been developed to amplify users' ability to navigate large tree-structured information systems. Information scent is a theoretical construct that captures one kind of interaction between task and display. Information scent is provided by task-relevant display cues, such as node labels on a tree that influence a user's visual search behavior and navigation decisions. An empirical Accuracy of Scent (AOS) score was developed to characterize a set of tasks that required users to find (Retrieval Tasks) or compare (Comparison Tasks) information in tree structures. Two experiments investigated the effect of information scent (tasks with different AOS scores) on performance with the Hyperbolic Tree Browser and the Microsoft Windows File Browser, which is a widely available conventional browser. Experiment 1 found no overall difference in performance time between the two browsers, but did reveal a marginal interaction of information scent with browser performance on Retrieval Tasks. On high AOS tasks the Hyperbolic showed faster performance, but on low AOS tasks the Windows File Browser showed faster performance. Experiment 2 focused only on the Retrieval tasks and revealed that Hyperbolic Tree users examined more tree nodes at a faster rate and visually searched through the tree hierarchy at a faster rate than users of a Windows File Browser lookalike, however, visual search paths were shortened in dense areas of the Hyperbolic Tree display when information scent was low. Two processes appear to affect visual search in the Hyperbolic display: strong information scent improves visual search, and the crowding of targets in a compressed region degrades visual search especially when there is weak information scent.
Experiments in social data mining: The TopicShop system BIBAFull-Text 54-85
  Brian Amento; Loren Terveen; Will Hill; Deborah Hix; Robert Schulman
Social data mining systems enable people to share opinions and benefit from each other's experience. They do this by mining and redistributing information from computational records of social activity such as Usenet messages, system usage history, citations, or hyperlinks. Some general questions for evaluating such systems are: (1) is the extracted information valuable? and (2) do interfaces based on the information improve user task performance? We report here on TopicShop, a system that mines information from the structure and content of Web pages and provides an exploratory information workspace interface. We carried out experiments that yielded positive answers to both evaluation questions. First, a number of automatically computable features about Web sites do a good job of predicting expert quality judgments about sites. Second, compared to popular Web search interfaces, the TopicShop interface to this information lets users select significantly more high-quality sites, in less time and with less effort, and to organize the sites they select into personally meaningful collections more quickly and easily. We conclude by discussing how our results may be applied and considering how they touch on general issues concerning quality, expertise, and consensus.

TOCHI 2003 Volume 10 Issue 2

Designing human-computer interfaces for quadriplegic people BIBAFull-Text 87-118
  Constantine E. Steriadis; Philip Constantinou
The need for participation in an emerging Information Society has led to several research efforts for designing accessibility solutions for disabled people. In this paper we present a method for developing Human-Computer Interfaces (HCIs) for quadriplegic people in modern programming environments. The presented method accommodates the design of scanning interfaces with modern programming tools, leading to flexible interfaces with improved appearance and it is based on the use of specially designed software objects called "wifsids" (Widgets For Single-switch Input Devices). The wifsid structure is demonstrated and 4 types of wifsids are analyzed. Developed software applications are to be operated by single-switch activations that are captured through the wifsids, with the employment of several modes of the scanning technique. We also demonstrate the "Autonomia" software application, that has been developed according to the specific methodology. The basic snapshots of this application are analyzed, in order to demonstrate how the wifsids cooperate with the scanning process in a user-friendly environment that enables a quadriplegic person to access an ordinary computer system.
Reading patterns and usability in visualizations of electronic documents BIBAFull-Text 119-149
  Kasper Hornbaek; Erik Frokjaer
We present an exploration of reading patterns and usability in visualizations of electronic documents. Twenty subjects wrote essays and answered questions about scientific documents using an overview+detail, a fisheye, and a linear interface. We study reading patterns by progression maps that visualize the progression of subjects' reading activity, and by visibility maps that show for how long different parts of the document are visible. The reading patterns help explain differences in usability between the interfaces and show how interfaces affect the way subjects read. With the overview+detail interface, subjects get higher grades for their essays. All but one of the subjects prefer this interface. With the fisheye interface, subjects use more time on gaining an overview of the document and less time on reading the details. Thus, they read the documents faster, but display lower incidental learning. We also show how subjects only briefly have visible the parts of the document that are not initially readable in the fisheye interface, even though they express a lack of trust in the algorithm underlying the fisheye interface. When answering questions, the overview is used for jumping directly to answers in the document and to already-visited parts of the document. However, subjects are slower at answering questions with the overview+detail interface. From the visualizations of the reading activity, we find that subjects using the overview+detail interface often explore the document further even when a satisfactory answer to the given question has already been read. Thus, overviews may grab subjects' attention and possibly distract them.
Evaluating a scientific collaboratory: Results of a controlled experiment BIBAFull-Text 150-176
  Diane H. Sonnenwald; Mary C. Whitton; Kelly L. Maglaughlin
The evaluation of scientific collaboratories has lagged behind their development. Do the capabilities afforded by collaboratories outweigh their disadvantages? To evaluate a scientific collaboratory system, we conducted a repeated-measures controlled experiment that compared the outcomes and process of scientific work completed by 20 pairs of participants (upper level undergraduate science students) working face-to-face and remotely. We collected scientific outcomes (graded lab reports) to investigate the quality of scientific work, post-questionnaire data to measure the adoptability of the system, and post-interviews to understand the participants' views of doing science under both conditions. We hypothesized that study participants would be less effective, report more difficulty, and be less favorably inclined to adopt the system when collaborating remotely. Contrary to expectations, the quantitative data showed no statistically significant differences with respect to effectiveness and adoption.
   The qualitative data helped explain this null result: participants reported advantages and disadvantages working under both conditions and developed work-arounds to cope with the perceived disadvantages of collaborating remotely. While the data analysis produced null results, considered as a whole, the analysis leads us to conclude there is positive potential for the development and adoption of scientific collaboratory systems.

TOCHI 2003 Volume 10 Issue 3

ScentTrails: Integrating browsing and searching on the Web BIBAFull-Text 177-197
  Christopher Olston; Ed H. Chi
The two predominant paradigms for finding information on the Web are browsing and keyword searching. While they exhibit complementary advantages, neither paradigm alone is adequate for complex information goals that lend themselves partially to browsing and partially to searching. To integrate browsing and searching smoothly into a single interface, we introduce a novel approach called ScentTrails. Based on the concept of information scent developed in the context of information foraging theory, ScentTrails highlights hyperlinks to indicate paths to search results. This interface enables users to interpolate smoothly between searching and browsing to locate content matching complex information goals effectively. In a preliminary user study, ScentTrails enabled subjects to find information more quickly than by either searching or browsing alone.
Effects of scent and breadth on use of site-specific search on e-commerce Web sites BIBAFull-Text 198-220
  Michael A. Katz; Michael D. Byrne
Users faced with Web sites containing many possibly relevant pages often have a decision to make about navigation: use the menu of links or use the provided site search function. Two studies were conducted to examine what users do when faced with this decision on e-commerce Web sites, and how users go about deciding which method to attempt. An exploratory study revealed a wide distribution of searching and browsing behavior across sites and users. Counter to some predictions, use of the site search functions did not yield faster or more accurate performance in locating products. Questionnaire data suggested that factors relevant to the menu structure, interface element prominence, information scent and user dispositions all influenced the decision of whether to browse or search a site for a product. A second experiment utilizing novel e-commerce sites and allowing for more control of factors found to be important in the first study found that browsing behavior was influenced by both the breadth and information scent of the menus. These results suggest that providing site search should not be used to compensate for poor menu design, and provide further evidence regarding the design of effective menu structures.
Are you looking at me? Eye contact and desktop video conferencing BIBAFull-Text 221-243
  David M. Grayson; Andrew F. Monk
Mutual gaze is an important conversational resource, but is difficult to provide using conventional video conferencing equipment due to the disparity between the position of the camera and the position of the eyes on the screen. Various elaborate inventions have been proposed to get around this problem but none have found wide use. The alternative explored here is that these expensive alternatives may be unnecessary. Users of conventional desktop video equipment may, under the right conditions, be able to learn to interpret what is at first sight inappropriate apparent gaze direction as signalling that the other person is "looking at me.
   "Data are presented from two experiments where an estimator judges where a gazer is looking. The gazer may be looking either at the desktop video image of the estimator or some point to the side. Experiment 1 compared two image sizes and two camera positions. While the size of the image (352 x 288 pixels versus 176 x 144) had no significant effect on participants' ability to judge where the gazer was looking, horizontally offsetting the position of the camera inhibited performance. Experiment 2 examined the effect of reducing the image size further. The smallest image size (88 x 72 pixels) resulted in poorer performance than the intermediate (176 x 144). The results show that it is possible for users of low cost desktop video conferencing to learn to interpret gaze direction to a very high degree of accuracy if the equipment is configured optimally. The practical and theoretical implications of these results are discussed.
Automatic generation of intelligent diagram editors BIBAFull-Text 244-276
  Sitt Sen Chok; Kim Marriott
The intelligent diagram is a recent metaphor for diagramming in which the underlying graphic editor parses the diagram as it is being constructed, performing error correction and collecting geometric constraints that capture the relationships between diagram components. During diagram manipulation a constraint solver uses these geometric constraints to maintain the diagram's semantics. We introduce the Penguins system. This automates the development of graphical editors that support the intelligent diagram metaphor. It takes a grammatical specification of a particular diagram language and generates an editor specialized for the creation, manipulation and parsing of diagrams in that visual language. We extend previous research in this area by allowing more expressive grammars, performing automatic error correction, and detailing how efficient incremental parsing has been achieved. We also provide an empirical evaluation of the system. This shows that the system can be used to generate customized editors for a wide variety of diagram languages, ranging from state transition diagrams to mathematical equations, with real-time incremental parsing and error correction.

TOCHI 2003 Volume 10 Issue 4

Introduction to multiple and collaborative tasks BIBFull-Text 277-280
  Peter Johnson; Jon May; Hilary Johnson
Task analysis for groupware usability evaluation: Modeling shared-workspace tasks with the mechanics of collaboration BIBAFull-Text 281-311
  David Pinelle; Carl Gutwin; Saul Greenberg
Researchers in Computer Supported Cooperative Work have recently developed discount evaluation methods for shared-workspace groupware. Most discount methods rely on some understanding of the context in which the groupware systems will be used, which means that evaluators need to model the tasks that groups will perform. However, existing task analysis schemes are not well suited to the needs of groupware evaluation: they either do not deal with collaboration issues, do not use an appropriate level of analysis for concrete assessment of usability in interfaces, or do not adequately represent the variability inherent in group work. To fill this gap, we have developed a new modeling technique called Collaboration Usability Analysis. CUA focuses on the teamwork that goes on in a group task rather than the taskwork. To enable closer links between the task representation and the groupware interface, CUA grounds each collaborative action in a set of group work primitives called the mechanics of collaboration. To represent the range of ways that a group task can be carried out, CUA allows variable paths through the execution of a task, and allows alternate paths and optional tasks to be modeled. CUA's main contribution is to provide evaluators with a framework in which they can simulate the realistic use of a groupware system and identify usability problems that are caused by the groupware interface.
A model for notification systems evaluation -- assessing user goals for multitasking activity BIBAFull-Text 312-338
  D. Scott McCrickard; C. M. Chewar; Jacob P. Somervell; Ali Ndiwalana
Addressing the need to tailor usability evaluation methods (UEMs) and promote effective reuse of HCI knowledge for computing activities undertaken in divided-attention situations, we present the foundations of a unifying model that can guide evaluation efforts for notification systems. Often implemented as ubiquitous systems or within a small portion of the traditional desktop, notification systems typically deliver information of interest in a parallel, multitasking approach, extraneous or supplemental to a user's attention priority. Such systems represent a difficult challenge to evaluate meaningfully. We introduce a design model of user goals based on blends of three critical parameters -- interruption, reaction, and comprehension. Categorization possibilities form a logical, descriptive design space for notification systems, rooted in human information processing theory. This model allows conceptualization of distinct action models for at least eight classes of notification systems, which we describe and analyze with a human information processing model. System classification regions immediately suggest useful empirical and analytical evaluation metrics from related literature. We present a case study that demonstrates how these techniques can assist an evaluator in adapting traditional UEMs for notification and other multitasking systems. We explain why using the design model categorization scheme enabled us to generate evaluation results that are more relevant for the system redesign than the results of the original exploration done by the system's designers.
Towards modeling individual and collaborative construction of jigsaws using task knowledge structures (TKS) BIBAFull-Text 339-387
  Hilary Johnson; Joanne Hyde
Recent years have seen an overwhelming interest in how people work together as a group. Both the nature of collaboration and research into how people collaborate is complex and multifaceted, with different research agendas, types of studies, and variations in the behavioral data collected. A better understanding of collaboration is needed in order to be able to make contributions to the design of systems to support collaboration and collaborative tasks. In this article, we combine relevant literature, past research, and a small-scale empirical study of two people individually and collaboratively constructing jigsaws. The objective is to make progress towards the goal of generating extensions to an existing task modeling approach, Task Knowledge Structures. The research described has enabled us to generate requirements for approaches to modeling collaborative tasks and also a set of requirements to be taken into account in the design of a computer-based collaborative virtual jigsaw.