Christof van Nimwegen

Locating Information in an Online Newspaper

In this study several aspects of the usability of an online newspaper are examined. More specifically, the effects of reading-manipulation techniques such as scrolling and using hyperlinks on finding information at different locations are studied. Subjects participated in two sessions with a one-week interval. In each session subjects received a number of searching tasks consisting of finding information at different locations in the newspaper. Speed and accuracy were measured, and afterwards subjects received a recognition task. In general subjects were highly satisfied with the online newspaper. Their performance on the searching tasks was very adequate, even on deeper levels. It took, logically, more time to locate the information by scrolling down or by using a hyperlink to go to a next level than when the hyperlink leading to the desired information was immediately available on screen. The recognition performance was also worse. Locating information after scrolling and after using a hyperlink took approximately the same amount of time, and the recognition performance was about equal. However, an interaction effect was also found between reading-manipulation technique and hypertextual level. In particular, finding information for which scrolling down on a deeper hypertextual level was necessary took extra time and probably extra cognitive resources, leading to a lower recognition performance. It is concluded that it is probably better, if possible, to avoid presenting information on deeper hypertextual levels for which scrolling is necessary.

The influence of structure and reading-manipulation on usability of hypertexts

Abstract This study investigates the influence of structure and reading-manipulation, and more importantly, the interaction between these two variables on usability of hypertexts. Four types of hypertexts are distinguished, differing in structure (hierarchical, or hierarchical with partial linearity) and reading-manipulation (scrolling or paging). A fifth extra hypertext containing a hierarchical structure with partial linearity and both paging and scrolling was also investigated. The information itself, a city guide about Utrecht with cultural and tourist information, was exactly the same in all hypertexts. Three aspects of usability were examined: efficiency , ease of learning and user-satisfaction . These aspects are measured by performance on 24 search tasks and a task reflecting insight into the structure of the hypertext. Also, questions about the structure of the hypertext and satisfaction with the system had to be answered. The results indicated that structure and reading-manipulation did not interact. There were, however, significant main effects of structure and reading-manipulation. A purely hierarchical structure was frequently more usable than a hierarchical structure with partial linearity, and scrolling appeared to be more useful than paging. The fifth alternative hypertext seemed slightly more usable than the hypertexts with linearity, but less usable than purely hierarchical hypertexts. The findings combined suggest that a purely hierarchical hypertext with scrolling is most useful, probably because this structure and kind of reading-manipulation both provide a clear insight into the structure of the hypertext. We assume this insight to be necessary for adequate performance.

Devices used for non-invasive tele homecare for cardiovascular patients : A systematic literature review

The aim of this Systematic Review (SLR) was to provide an overview of devices used for non-invasive tele health care by patients diagnosed with heart failure (HF). All English studies published in the past 10 years that focused on tele home care for coronary heart diseases, cardiac arrhythmia or heart failure patients were systematically searched in Scopus and Pubmed. Articles were selected if added value of tele-monitoring for these patients was studied. Selected titles and abstracts were screened to determine eligibility for further review. Types and number of devices per disease were then withdrawn and categorized for the three diseases. Eight devices were found in the literature to be used in non-invasive tele homecare for patients diagnosed with heart failure, of which weight scales and blood pressure monitors were most commonly used and are the most frequently occurring combination. The knowledge on which tele homecare devices are most commonly used gives insights into which devices are the best choice needed for patients with heart failure, where product suppliers and healthcare providers can respond to. The results create future directions for studying different aspects of tele homecare devices, such as usability aspects, which is an important factor for acceptance of telemedicine.