52799724
Comparative usability evaluation: critical incidents and critical threads
5855338
The development of cooperation: five years of participatory design in the virtual school
During the past five years, our research group worked with a group of public school teachers to define, develop, and assess network-based support for collaborative learning in middle school physical science and high school physics. From the outset, we committed to a participatory design approach. This design collaboration has now existed far longer than is typical of participatory design endeavors, particularly in North America. The nature of our interactions, and in particular the nature of the role played by the teachers has changed significantly through the course of the project. We suggest that there may be a long-term developmental unfolding of roles and relationships in participatory design.
2269827
Training wheels in a user interface
New users of high-function application systems can become frustrated and confused by the errors they make in the early stages of learning. A training interface for a commercial word processor was designed to make typical and troublesome error states “unreachable,” thus eliminating the sources of some new-user learning problems. Creating a training environment from the basic function of the system itself afforded substantially faster learning coupled with better learning achievement and better performance on a comprehension post-test. A control group spent almost a quarter of their time recovering from the error states that the training interface blocked off. We speculate on how this training strategy might be refined, and more generally, on how function should be organized in a user interface.
9978523
Community collective efficacy: structure and consequences of perceived capacities in the Blacksburg Electronic Village
Bandura's social cognitive construct "perceived self-efficacy" has been used widely to understand individual behavior as a function of domain-specific beliefs about personal capacities. Collective efficacy is the extension of the self-efficacy construct to organizations and groups; it refers to beliefs about collective capacities in specific domains. Our research is investigating the use of collective efficacy in understanding attitudes and behaviors of members of proximal residential communities with respect to issues like attachment, engagement, and sociality, specifically as modulated by use of the Internet and community networks. This paper describes our analysis of the structure and external validity of the collective efficacy construct.
15595014
Notification and awareness: synchronizing task-oriented collaborative activity
People working collaboratively must establish and maintain awareness of one another's intentions, actions and results. Notification systems typically support awareness of the presence, tasks and actions of collaborators, but they do not adequately support awareness of persistent and complex activities. We analysed awareness breakdowns in use of our Virtual School system--stemming from problems related to the collaborative situation, group, task and tool support--to motivate the concept of activity awareness. Activity awareness builds on prior conceptions of social and action awareness, but emphasizes the importance of activity context factors like planning and coordination. This work suggests design strategies for notification systems to better support collaborative activity.
148806746
Human-computer interaction: psychology as a science of design.
11499441
Matching RDF Graphs
The Resource Description Framework (RDF) describes graphs of statements about resources. RDF is a fundamental lower layer of the semantic web. This paper explores the equality of two RDF graphs in light of the graph isomorphism literature. We consider anonymous resources as unlabelled vertices in a graph, and show that the standard graph isomorphism algorithms, developed in the 1970's, can be used effectively for comparing RDF graphs. The techniques presented are useful for testing RDF software.
5426813
Machinima: digital performance and emergent authorship
This workshop investigates the emergent online dramatic form of "machinima", the co-option of video game engines or off-the-shelf software for dramatic production in a rapidly developing digital performance form. Workshop participants will engage with short examples of popular machinima productions. There will be discussion and demonstration of the machinima production process. The nexus between dramatic conventions, gameplay and traditional video production techniques will be explored. Participants will work with a short piece of a machinima, in the form of a scene created using the Sims 2 game. Participants will improvise, script and perform dialogue to provide meaning for the action. This workshop applies the insights of process drama, a field well developed in educational settings, to the development of machinima. It includes demonstration and participation in dramatic role, focusing on how the conventions of Role Distance and Role Protection apply to this developing field of digital game-based performance.
45352
A Practical Approach to Multiple Default Inheritance for Unification-Based Lexicons
This paper describes a unification-based lexicon system for NLP applications that incorporates mechanisms for multiple default inheritance. Such systems are intractable in the general case---the approach adopted here places a number of restrictions on the inheritance hierarchy in order to remove some of the sources of complexity while retaining more desirable properties. Implications of the design choices are discussed, comparisons are drawn with related work in computational linguistics and AI, and illustrative examples from the lexicons of German and English are given.
11155402
The effect of failure and repair distributions on consistency protocols for replicated data objects
The accessibility of vital information can be enhanced by replicating the data on several sites, and employing a consistency control protocol to manage the copies.
Various protocols have been proposed to ensure that only current copies of the data can be accessed. The effect these protocols have on the accessibility of the replicated data is investigated by simulating the operation of the network and measuring the performance. Several strategies for replica maintenance are considered, and the benefits of each are analyzed. The details of the simulations are discussed. Measurements of the reliability and the availability of the replicated data are compared and contrasted.
The sensitivity of the Available Copy and Dynamic-linear Voting protocols to common patterns of site failures and repairs is studied in detail. Exponential, Erlang, uniform, and hyperexponential distributions are considered, and the effect the second moments have on the results is analyzed. The relative performance of competing protocols is shown to be only marginally affected by non-exponential distributions, validating the robustness of the exponential approximations.
11544923
Unparsing RDF/XML
It is difficult to serialize an RDF graph as a humanly readable RDF/XML document. This paper describes the approach taken in Jena 1.2, in which a design pattern of guarded procedures invoked using top down recursive descent is used. Each procedure corresponds to a grammar rule; the guard makes the choice about the applicability of the production. This approach is seen to correspond closely to the design of an LL(k) parser, and a theoretical justification of this correspondence is found in universal algebra.