| Graphical Definitions: Expanding Spreadsheet Languages through Direct Manipulation and Gestures | | BIBAK | PDF | 1-33 | |
| Margaret M. Burnett; Herkimer J. Gottfried | |||
| In the past, attempts to extend the spreadsheet paradigm to support
graphical objects, such as colored circles or user-defined graphical types,
have led to approaches featuring either a direct way of creating objects
graphically or strong compatibility with the spreadsheet paradigm, but not
both. This inability to conveniently go beyond numbers and strings without
straying outside the spreadsheet paradigm has been a limiting factor in the
applicability of spreadsheet languages. In this article we present graphical
definitions, an approach that removes this limitation, allowing both simple and
complex graphical objects to be programmed directly using direct manipulation
and gestures, in a manner that fits seamlessly within the spread-sheet
paradigm. We also describe an empirical study, in which subjects programmed
such objects faster and with fewer errors using this approach than when using a
traditional approach to formula specification. Because the approach is
expressive enough to be used with both built-in and user-defined types, it
allows the directness of demonstrational and spread-sheet techniques to be used
in programming a wider range of applications than has been possible before. Keywords: D.1.1 [Programming Techniques]: Applicative (Functional) Programming; D.1.7
[Programming Techniques]: Visual Programming; D.3.3 [Programming Languages]:
Language Constructs and Features, Abstract data types; Data types and
structures; H.4.1 [Information Systems Applications]: Office Automations,
Spreadsheets, Design, Human Factors, Languages, Direct manipulation, Forms/3,
Gestures, Programming by demonstration | |||
| Controlling Access in Multiuser Interfaces | | BIBAK | PDF | 34-62 | |
| Prasun Dewan; Honghai Shen | |||
| Traditionally, access control has been studied in the areas of operating
systems and database management systems. With the advent of multiuser
interfaces, there is a need to provide access control in the user interface.
We have developed a general framework for supporting access control in
multiuser interfaces. It is based on the classical notion of an access matrix,
a generalized editing-based model of user-application interaction, and a
flexible model of user-user coupling. It has been designed to support flexible
control of all significant shared operations, high-level specification of
access control policies, and automatic and efficient implementation of access
control in a multiuser interface. It supports several new kinds of protected
objects including sessions, windows, and hierarchical active variables; a large
set of rights including not only the traditional semantic rights but also
interaction and coupling rights; a set of inference rules for deriving default
permissions; and a programming interface for implementing access control in
multiuser interfaces. We have implemented the framework as part of a system
called Suite. This article describes and motivates the framework using the
concrete example of Suite, identifies some of the difficult issues we faced in
its design, describes our preliminary experience with it, and suggests
directions for future work. Keywords: C.2.4 [Computer-Communication Networks]: Distributed Systems, distributed
applications; distributed databases; D.2.2 [Software Engineering]: Tools and
Techniques, user interfaces; D.2.6 [Software Engineering]: Programming
Environments, interactive; D.3.3 [Programming Languages]: Language Constructs,
input/output; H.1.2 [Models and Principles]: User/Machine Systems, human
factors; H.4.1 [Information Systems Applications]: Office Automation; I.7.2
[Text Processing]: Text Editing, Design, Human Factors, Languages, Access
control, collaboration, computer-supported cooperative work, groupware,
privacy, security, structure editors, user interface management systems | |||
| Achieving Convergence, Causality Preservation, and Intention Preservation in Real-Time Cooperative Editing Systems | | BIBAK | PDF | 63-108 | |
| Chengzheng Sun; Xiaohua Jia; Yanchun Zhang; Yun Yang; David Chen | |||
| Real-time cooperative editing systems allow multiple users to view and edit
the same text/graphic/image/multimedia document at the same time from multiple
sites connected by communication networks. Consistency maintenance is one of
the most significant challenges in designing and implementing real-time
cooperative editing systems. In this article, a consistency model, with
properties of convergence, causality preservation, and intention preservation,
is proposed as a framework for consistency maintenance in real-time cooperative
editing systems. Moreover, an integrated set of schemes and algorithms, which
support the proposed consistency model, are devised and discussed in detail.
In particular, we have contributed (1) a novel generic operation transformation
control algorithm for achieving intention preservation in combination with
schemes for achieving convergence and causality preservation and (2) a pair of
reversible inclusion and exclusion transformation algorithms for stringwise
operations for text editing. An Internet-based prototype system has been built
to test the feasibility of the proposed schemes and algorithms. Keywords: C.2.4 [Computer-Communication Networks]: Distributed Systems, distributed
applications; D.2.2 [Software Engineering]: Tools and Techniques, User
interfaces; H.1.2 [Models and Principles]: User/Machine Systems, Human factors;
H.5.3 [Information Interfaces and Presentation]: Group and Organization
Interfaces, Synchronous interaction; Theory and models, Algorithms, Design,
Human Factors, Causality preservation, computer-supported cooperative work,
consistency maintenance, convergence, cooperative editing, groupware systems,
intention preservation, operational transformation, REDUCE | |||
| Using Metalevel Techniques in a Flexible Toolkit for CSCW Applications | | BIBAK | PDF | 109-155 | |
| Paul Dourish | |||
| Ideally, software toolkits for collaborative applications should provide
generic, reusable components, applicable in a wide range of circumstances,
which software developers can assemble to produce new applications. However,
the nature of CSCW applications and the mechanics of group interaction present
a problem. Group interactions are significantly constrained by the structure
of the underlying infrastructure, below the level at which toolkits typically
offer control. This article describes the design features of Prospero, a
prototype CSCW toolkit designed to be much more flexible than traditional
toolkit techniques allow. Prospero uses a metalevel architecture so that
application programmers can have control over not only how toolkit components
are combined and used, but also over aspects of how they are internally
structured and defined. This approach allows programmers to gain access to
"internal" aspects of the toolkit's operation that affect how interaction and
collaboration proceed. This article explains the metalevel approach and its
application to CSCW, introduces two particular metalevel techniques for
distributed data management and consistency control, shows how they are
realized in Prospero, and illustrates how Prospero can be used to create a
range of collaborative applications. Keywords: C.2.4 [Computer-Communication Networks]: Distributed Systems, Distributed
applications; distributed databases; D.2.2 [Software Engineering]: Tools and
Techniques, User interfaces; H.1.2 [Models and Principles]: User/Machine
Systems, Human factors; H.5.3 [Information Interfaces and Presentation]: Group
and Organization Interfaces, Theory and models, Design, Human Factors,
Languages, Consistency control, consistency guarantees, data distribution,
divergency, metalevel programming, open implementation, software architecture | |||
| Hypertext versus Boolean Access to Biomedical Information: A Comparison of Effectiveness, Efficiency, and User Preferences | | BIBAK | PDF | 156-183 | |
| Barbara M. Wildemuth; Charles P. Friedman; Stephen M. Downs | |||
| This study compared two modes of access to a biomedical database, in terms
of their effectiveness and efficiency in supporting clinical problem solving
and in terms of user preferences. Boolean access, which allowed subjects to
frame their queries as combinations of keywords, was compared to hypertext
access, which allowed subjects to navigate from one database node to another.
The accessible biomedical data were identical across system versions.
Performance data were collected from two cohorts of first-year medical
students, each student randomly assigned to either the Boolean or the hypertext
system. Additional attitudinal data were collected from the second cohort. At
each of two research sessions (one just before and one just after their
bacteriology course), subjects worked eight clinical case problems, first using
only their personal knowledge and, subsequently, with aid from the database.
Database retrievals enabled students to answer questions they could not answer
based on personal knowledge alone. This effect was greater when personal
knowledge of bacteriology was lower. There were not statistically significant
differences between the two forms of access, in terms of problem-solving
effectiveness or efficiency. Students preferred Boolean access over hypertext
access. Keywords: H.3.2 [Information Storage and Retrieval]: Information Storage; H.3.3
[Information Storage and Retrieval]: Information Search and Retrieval; H.5.2
[Information Interfaces and Presentation]: User Interfaces, Human Factors,
Performance, Domain knowledge, intellectual access, medical education, problem
solving, usage effectiveness, usage efficiency, user preferences | |||
| Understanding and Constructing Shared Spaces with Mixed-Reality Boundaries | | BIBAK | PDF | 185-223 | |
| Steve Benford; Chris Greenhalgh; Gail Reynard; Chris Brown; Boriana Koleva | |||
| We propose an approach to creating shared mixed realities based on the
construction of transparent boundaries between real and virtual spaces. First,
we introduce a taxonomy that classifies current approaches to shared spaces
according to the three dimensions of transportation, artificiality, and
spatiality. Second, we discuss our experience of staging a poetry performance
simultaneously within real and virtual theaters. This demonstrates the
complexities involved in establishing social interaction between real and
virtual spaces and motivates the development of a systematic approach to mixing
realities. Third, we introduce and demonstrate the technique of mixed-reality
boundaries as a way of joining real and virtual spaces together in order to
address some of these problems. Keywords: H.4.3 [Information Systems Applications]: Communications Applications,
Computer conferencing and teleconferencing; H.5.1 [Information Interfaces and
Presentation]: Multimedia Information Systems, Artificial realities; H.5.3
[Information Interfaces and Presentation]: Group and Organization Interfaces,
Theory and models, Human Factors, Theory, Augmented reality, collaborative
virtual environments, CSCW, media-spaces, mixed reality, shared spaces,
telepresence, video, virtual reality | |||
| Using Nonspeech Sounds to Provide Navigation Cues | | BIBAK | PDF | 224-259 | |
| Stephen A. Brewster | |||
| This article describes three experiments that investigate the possibility of
using structured nonspeech audio messages called earcons to provide
navigational cues in a menu hierarchy. A hierarchy of 27 nodes and four levels
was created with an earcon for each node. Rules were defined for the creation
of hierarchical earcons at each node. Participants had to identify their
location in the hierarchy by listening to an earcon. Results of the first
experiment showed that participants could identify their location with 81.5%
accuracy, indicating that earcons were a powerful method of communicating
hierarchy information. One proposed use for such navigation cues is in
telephone-based interfaces (TBIs) where navigation is a problem. The first
experiment did not address the particular problems of earcons in TBIs such as
"does the lower quality of sound over the telephone lower recall rates," "can
users remember earcons over a period of time," and "what effect does training
type have on recall?" An experiment was conducted and results showed that
sound quality did lower the recall of earcons. However, redesign of the
earcons overcame this problem with 73% recalled correctly. Participants could
still recall earcons at this level after a week had passed. Training type also
affected recall. With "personal training" participants recalled 73% of the
earcons, but with purely textual training results were significantly lower.
These results show that earcons can provide good navigation cues for TBIs. The
final experiment used compound, rather than hierarchical, earcons to represent
the hierarchy from the first experiment. Results showed that with sounds
constructed in this way participants could recall 97% of the earcons. These
experiments have developed our general understanding of earcons. A hierarchy
three times larger than any previously created was tested, and this was also
the first test of the recall of earcons over time. Keywords: H.5.1 [Information Interfaces and Presentation]: Multimedia Information
Systems, Audio input/output; hypertext navigation and maps; H.5.2 [Information
Interfaces and Presentation]: User Interfaces, Evaluation/methodology;
interaction styles; J.7 [Computer Applications]: Computers in Other Systems,
Consumer products, Human Factors, Auditory interfaces, earcons, navigation,
nonspeech audio, telephone-based interfaces | |||
| Two-Handed Virtual Manipulation | | BIBAK | PDF | 260-302 | |
| Ken Hinckley; Randy Pausch; Dennis Proffitt; Neal F. Kassell | |||
| We discuss a two-handed user interface designed to support three-dimensional
neurosurgical visualization. By itself, this system is a "point design," an
example of an advanced user interface technique. In this work, we argue that
in order to understand why interaction techniques do or do not work, and to
suggest possibilities for new techniques, it is important to move beyond point
design and to introduce careful scientific measurement of human behavioral
principles. In particular, we argue that the common-sense viewpoint that "two
hands save time by working in parallel" may not always be an effective way to
think about two-handed interface design because the hands do not necessarily
work in parallel (there is a structure to two-handed manipulation) and because
two hands do more than just save time over one hand (two hands provide the user
with more information and can structure how the user thinks about a task). To
support these claims, we present an interface design developed in collaboration
with neurosurgeons which has undergone extensive informal usability testing, as
well as a pair of formal experimental studies which investigate behavioral
aspects of two-handed virtual object manipulation. Our hope is that this
discussion will help others to apply the lessons learned in our neurosurgery
application to future two-handed user interface designs. Keywords: I.3.6 [Computer Graphics]: Methodology and Techniques, interaction
techniques; H.5.2 [Information Interfaces and Presentation]: User Interfaces,
Input devices and strategies, Design, Experimentation, Human Factors,
Measurement, Bimanual asymmetry, haptic input, input devices, three-dimensional
interaction, two-handed interaction, virtual manipulation | |||
| The Integrality of Speech in Multimodal Interfaces | | BIBAK | PDF | 303-325 | |
| Michael A. Grasso; David S. Ebert; Timothy W. Finin | |||
| A framework of complementary behavior has been proposed which maintains that
direct-manipulation and speech interfaces have reciprocal strengths and
weaknesses. This suggests that user interface performance and acceptance may
increase by adopting a multimodal approach that combines speech and direct
manipulation. This effort examined the hypothesis that the speed, accuracy,
and acceptance of multimodal speech and direct-manipulation interfaces will
increase when the modalities match the perceptual structure of the input
attributes. A software prototype that supported a typical biomedical data
collection task was developed to test this hypothesis. A group of 20 clinical
and veterinary pathologists evaluated the prototype in an experimental setting
using repeated measures. The results of this experiment supported the
hypothesis that the perceptual structure of an input task is an important
consideration when designing a multimodal computer interface. Task completion
time, the number of speech errors, and user acceptance improved when interface
best matched the perceptual structure of the input attributes. Keywords: H.1.2 [Models and Principles]: User/Machine Systems, Human factors; H.5.2
[Information Interfaces and Presentation]: User Interfaces --
evaluation/methodology; input devices and strategies; interaction styles; H.5.3
[Information Interfaces and Presentation]: Group and Organization Interfaces --
theory and models; J.3 [Computer Applications]: Life and Medical Sciences,
Design, Experimentation, Human Factors, Measurement, Performance, Theory,
Direct manipulation, Input devices, Integrality, Medical informatics,
Multimodal, Natural-language processing, Pathology, Perceptual structure,
Separability, Speech recognition | |||
| Manual and Cognitive Benefits of Two-Handed Input: An Experimental Study | | BIBAK | PDF | 326-359 | |
| Andrea Leganchuk; Shumin Zhai; William Buxton | |||
| One of the recent trends in computer input is to utilize users' natural
bimanual motor skills. This article further explores the potential benefits of
such two-handed input. We have observed that bimanual manipulation may bring
two types of advantages to human-computer interaction: manual and cognitive.
Manual benefits come from increased time-motion efficiency, due to the twice as
many degrees of freedom simultaneously available to the user. Cognitive
benefits arise as a result of reducing the load of mentally composing and
visualizing the task at an unnaturally low level which is imposed by
traditional unimanual techniques. Area sweeping was selected as our
experimental task. It is representative of what one encounters, for example,
when sweeping out the bounding box surrounding a set of objects in a graphics
program. Such tasks cannot be modeled by Fitts' Law alone and have not been
previously studied in the literature. In our experiments, two bimanual
techniques were compared with the conventional one-handed GUI approach. Both
bimanual techniques employed the two-handed "stretchy" technique first
demonstrated by Krueger in 1983. We also incorporated the "Toolglass" technique
introduced by Bier et al. in 1993. Overall, the bimanual techniques resulted in
significantly faster performance than the status quo one-handed technique, and
these benefits increased with the difficulty of mentally visualizing the task,
supporting our bimanual cognitive advantage hypothesis. There was no
significant difference between the two bimanual techniques. This study makes
two types of contributions to the literature. First, practically we studied
yet another class of transaction where significant benefits can be realized by
applying bimanual techniques. Furthermore, we have done so using easily
available commercial hardware in the context to our understanding of why
bimanual interaction techniques have an advantage over unimanual techniques. A
literature review on two-handed computer input and some of the most relevant
bimanual human motor control studies is also included. Keywords: H.1.2 [Models and Principles]: User/Machine Systems, Human factors; H.5.2
[Information Interfaces and Presentation]: User Interfaces, input devices and
strategies; interaction styles; I.3.6 [Computer Graphics]: Methodology and
Techniques, interaction techniques, Design, Experimentation, Human Factors,
Measurement, Bimanual input, Input devices, Two-handed input | |||