Institute for Systems Research Technical Reports

Permanent URI for this collectionhttp://hdl.handle.net/1903/4376

This archive contains a collection of reports generated by the faculty and students of the Institute for Systems Research (ISR), a permanent, interdisciplinary research unit in the A. James Clark School of Engineering at the University of Maryland. ISR-based projects are conducted through partnerships with industry and government, bringing together faculty and students from multiple academic departments and colleges across the university.

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    The Design of History Mechanisms and Their Use in Collaborative Educational Simulations
    (1999) Plaisant, C.; Rose, A.; Rubloff, G.; Salter, R.; Shneiderman, B.; ISR
    Reviewing past events has been useful in many domains. Videotapes and flight data recorders provide invaluable technological help to sports coaches or aviation engineers. Similarly, providing learners with a readable recording of their actions may help them monitor their behavior, reflect on their progress, and experiment with revisions of their experiences. It may also facilitate active collaboration among dispersed learning communities. Learning histories can help students and professionals make more effective use of digital library searching, word processing tasks, computer-assisted design tools, electronic performance support systems, and web navigation.

    This paper describes the design space and discusses the challenges of implementing learning histories. It presents guidelines for creating effective implementations, and the design tradeoffs between sparse and dense history records. The paper also presents a first implementation of learning histories for a simulation-based engineering learning environment called SimPLE (Simulated Processes in a Learning Environment) for the case of a semiconductor fabrication module, and reports on early user evaluation of learning histories implemented within SimPLE.

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    Performance Benefits of Simultaneous over Sequential Menus as Task Complexity Increases
    (1999) Hochheiser, Harry; Kositsyna, Natalya; Ville, G.; Shneiderman, B.; ISR
    To date, experimental comparisons of menu layouts have concentrated on variants of hierarchical structures of sequentially presented menus. Simultaneous menus - layouts which present multiple active menus on a screen at the same time - are an alternative arrangement that may be useful in many web design situations.

    This paper describes an experiment involving a between-subject comparison of simultaneous menu and their traditional sequential counterparts. Twenty experienced web users used either simultaneous or sequential menus in a standard web browser to answer questions based on US Census data. For novice users performing simple tasks the simplicity of sequential menus appears to be helpful, but for most tasks and most users there is good evidence to believe that simultaneous menus speed performance and improve satisfaction. Design improvements can amplify the benefits of simultaneous menu layouts.

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    Facilitating Network Data Exploration with Query Previews: A Study of User Performance and Preference
    (1998) Tanin, E.; Lotem, Amnon; Haddadin, Ihab; Shneiderman, B.; Plaisant, C.; Slaughter, L.; ISR
    Current network data exploration systems which use command languages (e.g. SQL) or form fill-in interfaces fail to give users an indication of the distribution of data items. This leads many users to waste time posing queries which have zero-hit or mega-hit result sets. Query previewing is a novel visual approach for browsing huge networked information warehouses. Query previews supply data distribution information about the database that is being searched and give continuous feedback about the size of the result set for the query as it is being formed. Our within-subjects empirical comparison studied 12 subjects using a form fill-in interface, with and without query previews. We found statistically significant differences showing that query previews sped up performance by 1.6 to 2.1 times and led to higher subjective satisfaction.
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    Elastic Windows: A Hierarchical Multi-Window World-Wide Web Browser
    (1997) Kandogan, Eser; Shneiderman, B.; ISR
    The World-Wide Web (WWW) is becoming an invaluable source for the information needs of many users. However, current browsers are still primitive, in that they do no support many of the navigation needs of users, as indicated by user studies. They do not provide an overview and a sense of location in the information structure being browsed. Also they do not facilitate the organization and filtering of information nor aid users in accessing already visited pages without much cognitive demands. In this paper, a new browsing interface is proposed with multiple hierarchical windows and efficient multiple windows operations. It provides a flexible organization where users can quickly organize, filter, and restructure the information on the screen as they reformulate their goals. Overviews can give the user a sense of location in the browsing history as well as provide fast access to a hierarchy of pages.
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    Elastic Windows: Evaluation of Multi-Window Operations
    (1997) Kandogan, Eser; Shneiderman, B.; ISR
    Most windowing systems follow the independent overlapping windows approach, which emerged as an answer to the needs of the 1980s' technology. Due to advances in computers and display technology, and increased information needs, modern users demand more functionality from window management systems. We proposed Elastic Windows with improved spatial layout and rapid multi- window operations as an alternative to current window management strategies for efficient personal role management [kandogan]. In this approach, multi-window operations are achieved by issuing operations on window groups hierarchically organized in a space- filing tiled layout. This paper describes the Elastic Windows interface briefly and then presents a study comparing user performance with Elastic Windows and traditional window management techniques for 2, 6, and 12 window situations. Elastic Windows users had statistically significantly faster performance for all 6 and 12 window situations, for task environment setup, task environment switching, and task execution. These results suggest promising possibilities for multiple window operations and hierarchical nesting, which can be applied to the next generation of tiled as well as overlapped window managers.
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    The Eyes Have It: A Task by Data Type Taxonomy for Information Visualizations
    (1996) Shneiderman, B.; ISR
    A useful starting point for designing advanced graphical user interfaces is the Visual Information-Seeking Mantra: Overview first, zoom and filter, then details-on-demand. But this is only a starting point in trying to understand the rich and varied set of information visualizations that have been proposed in recent years. This paper offers a task by data type taxonomy with seven data types (1-, 2-, 3- dimensional data, temporal and multi- dimensional data, and tree and network data) and seven tasks (overview, zoom, filter, details-on-demand, relate, history, and extract).
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    Visual & Textual Consistency Checking Tools for Graphical User Interfaces
    (1996) Mahajan, Rohit; Shneiderman, B.; ISR
    Designing a user interface with a consistent visual design and textual properties with current generation GUI development tools is cumbersome. SHERLOCK, a family of consistency checking tools, has been designed to evaluate visual design and textual properties of interface, make the GUI evaluation process less arduous, and aid usability testing. SHERLOCK includes a dialog box summary table to provide a compact overview of visual properties of hundreds of dialog boxes of the interface. Terminology specific tools, like Interface Concordance, Terminology Baskets and Interface Speller have been developed. Button specific tools including Button Concordance and Button Layout Table have been created to detect variant capitalization, distinct typefaces, distinct colors, variant button sizes and inconsistent button placements. This paper describes software architecture, data structures and the use of SHERLOCK. An experiment with 60 subjects to study the effects of inconsistent interface terminology on user's performance showed 10-25% speedup for consistent interfaces. SHERLOCK was tested with four commercial prototypes; the corresponding outputs, analysis and feedback from designers of these applications is presented.
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    Designing Information-Abundant Websites
    (1996) Shneiderman, B.; ISR
    The deluge of web pages has generated dystopian commentaries on the tragedy of the flood as well as utopian visions of harnessing the same flood for constructive purposes. Within this ocean of information there are also lifeboat web pages with design principles, but often the style parallels the early user interface writings in the 1970s. The well-intentioned Noahs who write from personal experience as website designers, often draw their wisdom from specific projects, making their advice incomplete or lacking in generalizability. Their experience is valuable but the paucity of empirical data to validate or sharpen insight means that some guidelines are misleading. As scientific evidence accumulates, foundational cognitive and perceptual theories will structure the discussion and guide designers in novel situations.
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    Query Previews in Networked Information Systems
    (1995) Doan, Khoa; Plaisant, C.; Shneiderman, B.; ISR; CSHCN
    In a networked information system, there are three major obstacles facing users in a querying process: network performance, data volume and data complexity. In order to overcome these obstacles, we propose a two-phase approach of dynamic query formulation by volume preview. The two phases are the Query Preview andQuery Refinement. In the Query Preview phase, users formulate an initial query by selecting desired attribute values. The volume of matching data sets is shown graphically on Query bars which aid users to rapidly eliminate undesired data sets, and focus on a manageable number of relevant data sets. Query previews also prevent wasted steps by eliminating zero-hit queries. When the estimated number of data sets is low enough, the initial query is submitted to the network, which returns the metadata of the data sets for further refinement in the Query Refinement phase. The two-phase approach to query formulation overcomes slow network performance, and reduces the data volume and data complexity problems. This approach is especially appropriate for users who prefer the exploratory method to discover data patterns and exceptions during the query formulation process. Using this approach, we have developed dynamic query user interfaces to allow users to formulate their queries across a networked environment.
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    Browsing Hierarchical Data with Multi-Level Dynamic Queries and Pruning
    (1995) Kumar, Harsha P.; Plaisant, C.; Shneiderman, B.; ISR; CSHCN
    User often must browse hierarchies with thousands of nodes in search of those that best match their information needs. The PDQ Tree-browser (Pruning with Dynamic Queries) visualization tool was specified, designed and developed for this purpose. This tool presents trees in two tightly-coupled views, one a detailed view and the other an overview. Users can use dynamic queries, a method for rapidly filtering data, to filter nodes at each level of the tree. The dynamic query panels are user-customizable. Subtrees of unselected nodes are pruned out, leading to compact views of relevant nodes. Usability testing of the PDQ Tree- browser, done with 8 subjects, helped asses strengths and identify possible improvement. The PDQ Tree-browser was used in Network Management (600 nodes) and University Finder (1100 nodes) applications. A controlled experiment, with 24 subjects, showed that pruning significantly improved performance speed and subjective user satisfaction. Future research directions are suggested.