Roy Rada

Interacting with hypertext: a meta-analysis of experimental studies

The meta-analysis compared and synthesized the results of 23 experimental studies on hypertext. The analysis was based on 56 pairs of effect sizes and significance levels of the impact of users, tasks, and tools on interactions with hypertext. This analysis focused on three factors that prevailingly influence the use of hypertext: the cognitive styles and spatial ability of users; the complexity of tasks; and the structure of information organization and the visualization of the structure. The meta-analysis found that this group of experimental studies reported significantly discrepant findings, indicating that substantial differences exist among individual experiments. Individual differences in cognition did not yield enough evidence to conclude that the effect sizes are significantly apart from zero. The meta-analysis showed that the overall performance of hypertext users tended to be more effective than that of nonhypertext users, but the differences in efficiency measures were consistently in favor of nonhypertext users. Users benefited more from hypertext tools for open tasks. Overall, the complexity of tasks has the largest combined effect sizes. Graphical maps that visualize the organization of hypertext have significant impact on the usefulness of a hypertext system. This meta-analysis raised two issues concerned with the present hypertext literature: (a) the absence of a taxonomy of tasks for analyzing and comparing hypertext usability across studies, and (b) the weaknesses of the connections between abstract hypertext reference models and specific hypertext systems. These weaknesses may considerably undermine the significance of individual findings on hypertext usability. Results of the meta-analysis suggest that the discrepancies among empirical findings are related to these weaknesses. Future work on hypertext usability should emphasize task taxonomies along with longitudinal and ethnographic studies for a deep understanding of the interactions between users and hypertext. Recommended research issues for the future are highlighted in Section 5.

Understanding the Influence of Perceived Usability and Technology Self-Efficacy on Teachers' Technology Acceptance

Abstract The Technology Acceptance Model (TAM) represents how users come to accept and use a given technology and can be applied to teachers’ use of educational technologies. Here the model is extended to incorporate teachers’ perceived usability and self-efficacy measures toward the technologies they are currently using. The authors administered a survey to K–12 teachers in two rural school districts in Virginia, and 99 teachers responded. We then analyzed the responses with both reliability statistics and general linear modeling techniques. The results indicated that the incorporation of perceived usability into the TAM explained more variance and was more influential to TAM elements than its absence, thereby supporting the importance, positive influence, and necessity of evaluating usability when investigating educational technology acceptance and usage behavior. Furthermore, the study found teachers’ technology self-efficacy (TSE) was more beneficial to the TAM than their computer self-efficacy (CSE); however, this impact might vary for the evaluations of different populations and technologies.

The new media

Today. hig events in high rechnnlog) include the convergence between information and communication industries (computer, telephone, cable television. and broadcast television). the emphasis hy such giants as Microsoft on hypermedia products. and the manufacture of palmtop computers. In this new age, a field engineer may access a simulation of a plane engine on a palmtop computer while in the process of repairing the engine. A student at home writes an essay on a palmtop and incorporates moving images from a hypermedia encyclopedia into the essay before electronically mailing it to the teacher. When will this new age come and what hinders its pmgres+ Do the lack of sunConsider the prod~rion and dissemination of a document wirh text and images. For a paper document. whether the author uses a pen. a typewriter. or a computer. so long as the final product is legible on paper and can he reproduced, the availahility of the product is not a technological matter. If the document is to he disreminatrd electronically and is

Hypertext: from Text to Expertext

Text principles reading model writing model systems text structure reading tools writing tools epilogue exercises small volume history 1960s 1970s principles database network interface systems writing systems browsing systems software engineering environments text to microtext from microtext to text large volume paper indices memex online bibliographies word based principles indexing language principles retrieval interface evaluation text databases an online session word based systems indexing language systems searching and browsing systems hypertext to hypertext translating meta-languages mapping merging languages collaborative technology principles people principles systems authoring discussion annotation publishing principles links distributed intelligent microtext intelligent macrotext intelligent grouptext expertext systems for software requirements conclusion from text to expertext the environment directions exercises answers macrotext intelligent grouptext expertext systems for software requirements epilogue exercises 6 conclusion from text to expertext text microtext macrotext grouptext expertext the environment - system model economics directions - new structures new methods requirements exercises 7 answers microtext answers - macrotext answers - group text answers - expertext answers - conclusion answer.

Structured hypertext with domain semantics

One important facet of current hypertext research involves using knowledge-based techniques to develop and maintain document structures. A semantic net is one such technique. However, most semantic-net-based hypertext systems leave the linking consistency of the net to individual users. Users without guidance may accidentally introduce structural and relational inconsistencies in the semantic nets. The relational inconsistency hinders the creation of domain information models. The structural inconsistency leads to unstable documents, especially when a document is composed by computation with traversal algorithms. This work tackles to above problems by integrating logical structure and domain semantics into a semantic net. A semantic-net-based structured-hypertext model has been formalized. The model preserves structural and relational consistency after changes to the semantic net. The hypertext system (RICH) based on this model has been implemented and tested. The RICH system can define and enforce a set of rules to maintain to integrity of the semantic net and provide particular support for creating multihierarchies with the reuse of existing contents and structures. Users have found such flexible but enforceable semantics to be helpful.

Review: Expert systems and evolutionary computing for financial investing: A review

This innovative, experimental approach to a literature review begins with queries for finance-related articles to the Expert Systems with Applications literature database. A classification language is constructed, and retrieved articles are systematic indexed. Hypotheses are offered about the patterns in the distribution of indexed concepts. Results include that authors tended to use expert systems tools in the early 1990s but evolutionary computation tools in mid-2000s. However, the most common financial application area in both the earlier and later periods was financial accounting. One trend in the latest work is to merge both knowledge-based and evolutionary approaches. Opportunities exist to reuse the knowledge bases built for the financial accounting work for speculative investing.

Converting a textbook to hypertext

Traditional documents may be transformed into hypertext by first reflecting the documents logical markup in the hypertext (producing first-order hypertext) and then by adding links not evident in the document markup (producing second-order hypertext). In our transformation of a textbook to hypertext, the textbook is placed in an intermediate form based on a semantic net and is then placed into the four hypertext systems: Emacs-Info, Guide, HyperTies, and Super-Book. The first-order Guide and SuperBook hypertexts reflect a depth-first traversal of the semantic net, and the Emacs-Info and HyperTies hypertexts reflect a breadth-first traversal. The semantic net is augmented manually, and then new traversal programs automatically generate alternate outlines. An index based on work patterns in the textbook is also automatically generated for the second-order hypertext. Our suite of programs has been applied to a published textbook, and the resulting hypertexts are publicly available.

A graphical thesaurus-based information retrieval system

Abstract Information retrieval systems often rely on thesauri or semantic nets in indexing documents and in helping users search for documents. Reasoning with these thesauri resembles traversing a graph. Several algorithms for matching documents to queries based on the distances between nodes on the graph (terms in the thesaurus) are compared to the evaluations of people. The “broader-than” relationships of both a medical and a computer science thesaurus when coupled with a simple average path length algorithm are able to simulate the decisions of people regarding the conceptual similarity of documents and queries. A graphical presentation of a thesaurus is connected to a multi-window document retrieval system and its ease of use is compared to a more traditional thesaurus-based information retrieval system. While substantial evidence exists that the graphics and multiple windows can be useful, our experiments have shown, as have many other human-computer interface experiments, that a multitude of factors come into play in determining the value of a particular interface.

Operations research survey and computer simulation of waiting times in two medical outpatient clinic structures.

Outpatient services are increasingly recognised as an important component of health care provision and may be improved through the application of modern management techniques. We have performed a time and role audit of consultation and waiting times in two medical clinics using different queuing systems: namely, a serial processing clinic where patients wait in a single queue and a quasi-parallel processing clinic where patients are directed to the shortest queue to maintain clinic flow. Data collected were used to construct a computer simulation of patient flows in clinic. Assessment of patient satisfaction in the clinic process was determined using a self-administered questionnaire. Mean waiting time was shorter in the quasi-parallel processing clinic: 26 (SD 17) minutes compared with 36(24) minutes in the serial processing clinic. In the serial processing clinic 61% of patients waited more than 30 minutes compared with 41% in the quasi-parallel processing clinic. In the serial processing clinic 8% of 142 patients surveyed complained of the time spent waiting. The computer simulation we produced was able to determine waiting times with different clinic structures. The simulation showed that reductions in waiting time up to 30% might be achieved by changing our serial processing clinic to a quasi-parallel processing one. Performance of medical outpatient clinics can be improved by examining and changing clinic management. Computer simulation of outpatient clinics offers a means of assessing the impact of such changes on waiting time in clinic and on waiting lists.

Merging thesauri: principles and evaluation

An investigation is reported of ways to take advantage of the semantics in thesauri to improve: (1) indexing by providing descriptions of documents as sets of terms from the thesaurus; and (2) retrieval by assessing the relevance of documents to a query. Thesauri need to be updated to account for the evolution of the field they cover. Accordingly, various augmentation algorithms and methods to assess the usefulness of these augmentations are being studied. The augmentations consist of merging two existing thesauri. By keeping a consistent level of complexity among the structure manipulated by the merging algorithm, the reasoning method, and the evaluation procedure, an improvement of the performance of the merged thesaurus on both document indexing and retrieval is demonstrated. >