Abstract not found

Landmarks are significant in one’s formation of a cognitive map of both physical environments and electronic information spaces. Landmarks are defined in physical space as having key characteristics that make them recognizable and memorable in the environment. The challenge of defining measurable features of landmarks that can be used in designing and recognizing landmarks in information spaces is explored. By drawing on diverse areas such as urban planning, architecture, cognitive science and hypertext, a coherent definition of a landmark is proposed, which is relevant to both physical and electronic spaces. It is argued that landmarks can be classified in terms of visual, cognitive and structural dimensions, which has implications for how environments can be designed or built in such a way that landmarks will emerge appropriately for unique situations.

This paper describes a method for an information filtering agent to learn user's preferences. The proposed method observes user's reactions to the filtered documents and learns from them the profiles for the individual users. Reinforcement learning is used to adapt the most significant terms that best represent user's interests. In contrast to conventional relevance feedback methods which require explicit user feedbacks, our approach learns user preferences implicitly from direct observations of browsing behaviors during interaction. Field tests have been made which involved 10 users reading a total of 18,750 HTML documents during 45 days. The proposed method showed superior performance in personalized information filtering compared to the existing relevance feedback methods. Keywords Information filtering agents, learning reinforcement learning, user modeling. user's preferences, 1.

We report on a field study about how software developers experience disorientation when using the Eclipse Java integrated development environment. We analyzed the data using the theory of visual momentum, identifying three factors that may lead to disorientation: the absence of connecting navigation context during program exploration, thrashing between displays to view necessary pieces of code, and the pursuit of sometimes unrelated subtasks. 1.

Difficulties with orientation are common in hyperdocuments. This paper describes an exploratory study into the role of a navigation map, as a helping tool, during browsing processes. We tried to establish the influence of this navigational tool, provided by a hypermedia prototype, in retrieval tasks. Twenty-two students tested this prototype and some data were collected: scores obtained in a task-test and a record of the path followed by the subjects. With these data we defined a set of ratios as an attempt to understand the subjects ’ browsing processes. Findings suggest that the map was not effective in the ameliorative role. Perhaps it is not wise to assume that a map that helps performance in a spatial context also forms an aid in a hypermedia environment under a nonhierarchical model. Hypermedia environments are complex systems based in a nonlinear

A pervasive criticism of hypertext systems is that users tend to lose their way. Although much work has been done to address this "lost in hyperspace" problem, it still remains unresolved, even accepted as an inevtaible feature. But using the "lost in hyperspace" problem as an example of usability problems, we argue usabilityproblems are not user problems. Once viewed like this, more appropriate solutions are applied to address it. We argue that some usability problems have been mis-classified as "psychological" and therefore are only palliated rather than cured. However, we show that there is much scope for new systems approaches that avoid such problems, and which offer considerably more creative ways of going about design of interactive systems. Keywords Hypertext, lost in hyperspace, conceptual model, executable user models, multidisciplinary design 1. Introduction Ever since Vannevar Bush envisioned his hypertext Memex in 1945 (Bush, 1995), many diverse hypertext sys...

. This paper concerns the need for enhancing hypertext systems with security protection. We identify the elements of hypertext models which must be subject to security control. Main attention is directed toward hypertext and access control preventing the information stored from unauthorized disclosure or modification. From the class of known security models we consider the Discretionary Models, the Mandatory Models, the Personal Knowledge Approach, and the Clark and Wilson Model as candidates for the underlying security paradigm of hypertext systems. The security techniques considered originate from emphasizing different goals: Discretionary Models try to assign access privileges to users, Mandatory Models try to keep secrets, the Personal Knowledge Approach focuses on enforcing the constitutional right of informational self-determination of humans, and the Clark and Wilson Model tries to adapt common commercial security practice to computerized systems. The applicability of these secu...

. Mandala is a system for using images to represent, access, and organize web information. Images from a web page represent the content of the page. Double-clicking on an image signals a web browser to display the associated page. People identify groups of images visually and share them with Mandala by dragging them between windows. Groups of image representations are stored as imagemaps, making it easy to save visual bookmarks, site indexes, and session histories. Image representations afford organizations that scale better than textual displays while revealing a wealth of additional information. People can easily group related images, identify relevant images, and use images as mnemonics. Hypermedia systems that use image representations seem less susceptible to classic hypertext problems. When image representations are derived from a proxy server cache, the resulting visualizations increase cache hitrates, access to relevant resources, and resource sharing, while revealing the dynam...

Disorientation and cognitive overhead are two interrelated problems that may in fact ultimately limit the usefulness of hypertext. Cognitive overhead upon the author arises from a viewpoint that sees the author as the person solely responsible for inserting all links within her work. This includes all links between the anchors in her own work and those in external frames, as well as cross-links between the anchors within her own work. The need for an author to be aware, for each anchor within her work, of all possible other anchors makes the insertion of such links an O(N 2 ) problem where N is the number of possible anchors in the hypertext universe. To reduce this to an O(N ) problem this paper proposes the use of bi-directional intelligent anchors. These are anchors that have both a knowledge of the concepts that a potential reader would be seeking were she to arrive at the anchor, together with a knowledge of the concepts that a reader would be seeking were she to jump from that ...

What is literally digital about literacy today is how much of what is read and written has been electronically conveyed as binary strings of one and zeros, before appearing as letters, words, numbers, symbols, and images on the screens and pages of our literate lives. This digital aspect of literacy, invisible to the naked eye, is the very currency that drives the global information economy. Yet what we see of this literacy is remarkably continuous with the literacy of print culture, right down to the very serifs that grace many of the fonts of digital literacy. So begins the paradox that while digital literacy constitutes an entirely new medium for reading and writing, it is but a further extension of what writing first made of language. 1 On the one hand, long-standing scholars of this new medium, such as Donald Leu, favor treating digital literacy as itself a “great transformation, ” holding that such technologies do nothing less than “rapidly and continuously redefine the nature of literacy. ” 2 We tend, on the other hand, to look to the continuities and extensions achieved through the introduction of digital literacy into a print culture, while seeking to understand how these developments encourage what is most admirable about the nature of literacy. 3