Browsing by Author "Chewar, Christa M."

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    Claims Reuse for Notification Systems Design: LINK-UP Vision and IRC Equations
    Chewar, Christa M.; McCrickard, D. Scott (Department of Computer Science, Virginia Polytechnic Institute & State University, 2003)
    Extending previous work on the concept of claims reuse, an approach for cataloging and reusing design knowledge in human-computer interaction, we introduce a vision for a system, LINK-UP. The system is intended to parallel a usability engineering process that involves claims analysis. While we initially target notification system design support, we believe that the general method is extensible to other design concerns. A key aspect of the LINK-UP system is its iterative assessment of critical parameters---essential target values that describe anticipated user goals. In notification systems design, three critical parameters are interruption, reaction, and comprehension, referred to as IRC. While the parameter values represent abstract concepts, a pivotal challenge in the development of LINK-UP is determining methods for consistent and accurate parameter specification. To this end, we introduce equations for calculating user's model IRC parameters, either from analytical or empirical data. Presented here are details of variable justification and equation behavior. Future work will assess consistency and accuracy of artifact classifications using the equations.
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    Designing Attention-Centric Notification Systems: Five HCI Challenges
    McCrickard, D. Scott; Chewar, Christa M. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2005)
    Through an examination of the emerging domain of cognitive systems, with a focus on attention-centric cognitive systems used for notification, this document explores the human-computer interaction challenges that must be addressed for successful interface design. This document asserts that with compatible tools and methods, user notification requirements and interface usability can be abstracted, expressed, and compared with critical parameter ratings; that is, even novice designers can assess attention cost factors to determine target parameter levels for new system development. With a general understanding of the user tasks supported by the notification system, a designer can access the repository of design knowledge for appropriate information and interaction design techniques (e.g., use of color, audio features, animation, screen size, transition of states, etc), which have analytically and empirically derived ratings. Furthermore, usability evaluation methods, provided to designers as part of the integrated system, are adaptable to specific combinations of targeted parameter levels. User testing results can be conveniently added back into the design knowledge repository and compared to target parameter levels to determine design success and build reusable HCI knowledge. This approach is discussed in greater detail as we describe five HCI challenges relating to cognitive system development: (1) convenient access to basic research and guidelines, (2) requirements engineering methods for notification interfaces, (3) better and more usable predictive modeling for pre-attentive and dual-task interfaces, (4) standard empirical evaluation procedures for notification systems, and (5) conceptual frameworks for organizing reusable design and software components. This document also describes our initial work toward building infrastructure to overcome these five challenges, focused on notification system development. We described LINK-UP, a design environment grounded on years of theory and method development within HCI, providing a mechanism to integrate interdisciplinary expertise from the cognitive systems research community. Claims allow convenient access to basic research and guidelines, while modules parallel a lifecycle development iteration and provide a process for requirements engineering guided by this basic research. The activities carried out through LINK-UP provide access to and interaction with reusable design components organized based on our framework. We think that this approach may provide the scientific basis necessary for exciting interdisciplinary advancement through many fields of design, with notification systems serving as an initial model. A version of this document will appear as chapter 3 in the book Cognitive Systems: Human Cognitive Models in Systems Design edited by Chris Forsythe, Michael Bernard, and Timothy Goldsmith resulting from a workshop led by the editors in summer 2003. The authors are grateful for the input of the workshop organizers and conference attendees in the preparation of this document.
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    Entangled Design Knowledge: Relationships as an Approach to Claims Reuse
    Wahid, Shahtab; McCrickard, D. Scott; Chewar, Christa M.; Lee, Jason Chong (Department of Computer Science, Virginia Polytechnic Institute & State University, 2006)
    As a discipline, human-computer interaction produces creative and innovative designs that could provide a reusable collection of design knowledge on which future efforts could build. It is unfortunate that so much of this knowledge is not fully reused by designers today. To encourage the use of previously identified HCI knowledge, we propose a model of reuse building on Carroll?s notion of claims, design knowledge components that capture the positive and negative psychological effects of design features. We address four challenges associated with reuse in a library of claims, adopted from software engineering?a discipline in which the notion of reuse has been prevalent for quite some time. Building on Krueger?s definition of reuse and his conceptualization of four key aspects?abstraction, selection, specification, and integration?we propose a reuse approach based on incorporating these four aspects into the design process. To abstract, select, specify and integrate claims, we identify claim relationships, descriptions of connections between claims. We portray how claim relationships can be used to aid in identifying claim types, searching for claims, creating new claims, and aggregating claims. By integrating relationships into a claims library, we demonstrate how they can be applied to assist claims reuse and present studies related to each application of the relationships.
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    Making a Case for Hci: Comparing Materials for Case-based Teaching
    Somervell, Jacob; Chewar, Christa M.; McCrickard, D. Scott (Department of Computer Science, Virginia Polytechnic Institute & State University, 2004)
    This paper investigates case-based methods for bridging the conflicting goals of providing both topic coverage and practical experience in teaching humancomputer interaction (HCI). Case-based methods rely on design, development, and testing material for existing or on-going projects to provide details on difficult decisions and solutions in the interface creation process. Cases are touted as alternatives to real experience (immensely important in HCI courses) and provide rich environments for computer science instruction. We evaluate benefits and limitations of five types of case materials--contemporary articles, professionally prepared cases, familiar interfaces, ongoing development projects, and incomplete information (jigsaw)--to probe how they should be structured and approached by an HCI instructor. Through an experience that assessed case-based activities in an undergraduate HCI course, we determined tradeoffs relating to student participation, preparation characteristics, and short- and long-term learning outcomes. Professionally prepared case materials provided a sense of comfort in preparation, but were surpassed by familiar interfaces in terms of performance and post-use feedback, leading to recommendations for case materials development and adoption of case-based learning for HCI. Based on our results, we can make several conclusions that should influence selection and development of materials for casebased pedagogy, and we illustrate the need for structured case creation processes that can be performed conjointly with system development efforts.
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    Persistent virtual identity in community networks: Impact to social capital value chains
    Chewar, Christa M.; McCrickard, D. Scott; Carroll, John M. (Department of Computer Science, Virginia Polytechnic Institute & State University, 2003)
    Community networks are digital infrastructures designed to strengthen bonds and build social capital between members of a community, facilitating accomplishment of goals. As we consider how community network implementations can be improved, we recognize the potential that social translucence and activity notification introduces to other forms of CSCW. We investigate how the underlying notion of persistent virtual identity---established at logon---impacts user perception of community networks and their social capital production process. To approach this question, we introduce a design model that reconciles various computer-mediated communication research contributions with support for typical community network scenarios of use. Using this model, we perform an inspection on existing community network implementations. Based on the insight gained through this analysis, we introduce a generic prototype that allows survey of user reaction to community network design elements under differing conditions of persistent virtual identity implementation and usage motivation---the results frame a value-chain understanding of conceptual tradeoffs.
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    Spiraling Toward Usability: An Integrated Design Environment and Management System
    Lee, Jason Chong; Wahid, Shahtab; Chewar, Christa M.; Congleton, Ben; McCrickard, D. Scott (Department of Computer Science, Virginia Polytechnic Institute & State University, 2005-09-01)
    Decades of innovation in designing usable (and unusable) interfaces have resulted in a plethora of guidelines, usability engineering methods, and other design tools. However, novice developers often have difficulty selecting and utilizing theory-based design tools in a coherent design process. This work introduces an integrated design environment and knowledge management system, LINK-UP. The central design record (CDR) module, provides tools to enable a guided, coherent development process. The CDR aims to prevent breakdowns occurring between design and evaluation phases both within the development team and during design knowledge reuse processes. We report on results from three case studies illustrating novice designers use of LINK-UP. A design knowledge IDE incorporating a CDR can help novice developers craft interfaces in a methodical fashion, while applying, verifying, and producing reusable design knowledge. Although LINK-UP supports a specific design domain, our IDE approach can transfer to other domains.
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    User-Centered Critical Parameters for Design Specification, Evaluation, and Reuse: Modeling Goals and Effects of Notification Systems
    Chewar, Christa M. (Virginia Tech, 2005-07-15)
    Responding to the need within the human-computer interaction field to address ubiquitous and multitasking systems more scientifically, this research extends the usefulness of a new research framework for a particular class of systems. Notification systems are interfaces used in a divided-attention, multitasking situation, attempting to deliver current, valued information through a variety of platforms and modes in an efficient and effective manner. Through review of literature and experiences with empirical dual-task perceptual studies, we recognize a lack of unifying framework for understanding, classifying, analyzing, developing, evaluating, and discussing notification systems--fundamentally inhibiting scientific growth and knowledge reuse that should help designers advance the state-of-the-art. To this end, we developed a framework (referred to as the IRC framework) for notification systems research based on a core taxonomy of critical parameters describing user goals. Next, we extend the framework, focusing on three key aspects: 1) a system description process, allowing articulation of abstract design objectives that focus on critical user requirements; 2) interface usability evaluation tools, enabling comparison of the design and user's models, while supporting generalizability of research and early identification of usability concerns; and 3) design comparison and reuse mechanisms, saving time and effort in requirements analysis and early design stages by enabling design reuse and appreciation of design progress. Results from this research include the development of tools to express IRC design models (IRCspec) and user's models (IRCresults), and the extension of the critical parameters concept. Validation studies with novice designers show sufficient assessment accuracy and consistency. Leveraging these tools that help designers express abstract, yet critical, design intentions and effects as classification and retrieval indices, we develop a repository for reusable design knowledge (a claims library). Responding to challenges of design knowledge access that we observed through initial user testing, we introduce a vision for an integrated design environment (LINK-UP) to operationalize the IRC framework and notification systems claims library in a computer-aided design support system. Proof-of-concept testing results encourage the thought that when valuable design tools embody critical parameters and are coupled with readily accessible reusable design knowledge, interface development will improve as a scientific endeavor.