Abstract 1 1 Introduction 2
Synchronization and Data Interchange
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- 6Summary and Research Implication
5.4Synchronization and Data InterchangeWindows may be synchronized in three ways. The first is one-way synchronization. When change occurs in one window, it will cause another window to change state but not the other way around. The second is two-way synchronization. A change in one window will synchronize with another window. The third one is no-synchronization. Both windows maintain their internal states independently. Regardless of whether navigation tools are presented at the same or at different times and in the same or different windows, the navigation tools should be capable of being synchronized to each other. This can be done by passing display data or tool state information or both. The synchronization may be in terms of:
For instance, if three windows are used, one showing a global tree map, another the files in a directory list, and one showing file contents, the global tree map could have an indicator to show which files are being displayed in the file directory list. The file content viewer may display the file that is selected in the file list. In this case, the navigation might be done in either the tree map or the file list. Navigation via the tree map should change the file list contents. It is conceivable that each navigational tool has its own internal representation of document space and navigation data. In order to communicate between tools, only common data can be interchanged. The representation of current place, or current selection, etc., will have to be converted to some shared representation. Shaw & Garlan (1996) classify user interface software systems as using shared states, events or both. The classification is given as follows: Event – all information is passed through event messages. Pure state – no event information, module responds to check state change. Shared state with hint – information is passed through state. Event is used as notify change. State plus events – uses both mechanisms. Event provides additional information.
From this literature review, there are many research topics still open concerning questions of designing useful navigation systems. These include basic research in appropriate cognition models for navigating artificial space, empirical studies in usage of navigation tools, design frameworks for navigation tools, etc. Some research topics are listed in the order in which the preceding discussion is presented. A meaning of “document” and “document space” are stipulated in the first section. Many dimensions of a document space are described. A navigation tool for a certain dimension will have a variation in ease of use. For example, a navigation tool in the time dimension will be somewhat different from one targeted for managing static “current” document space. Section 2 investigates the mean of a document space and the effect of the shape of the document space on the utility of navigation tools. Specifically, a display space will be utilized only in some conditions. The collecting of evidence about what an average of document space looks like would be useful. Metrics are also needed in order to describe the shape of a space. For instance, hierarchical structures of file systems have a highly skewed distribution in width and depth, so that a normal tree layout will show a lot of empty space in presenting a high variation of width and depth. File list presentations will have a high variation depending on list length. The relationship of file count to document is also an interesting issue. Research in information retrieval systems considers documents as records, and the document-term relations have been extracted and presented in many visualization tools. Further developments in this area await user studies to determine the types of tasks that support superior visual exploration of document collections and sets. The large document collections on the WWW have been stimulating much research to identify their size, structure, and topology. Section 3 discusses information needed in navigation: what information is needed for navigation and when, i.e. during which phase of interaction. For instance, overview diagrams have proven to be useful; we may further question when, in what a moment of the navigation process, they might be helpful. One may expect that an overview diagram would be used when users first encounter space; it would be an aid to understanding the structure of the space and might never be used for walking through the space. It may be argued that an overview diagram is also used to make sense of “where am I?” in space. In this case, an overview diagram should be presented through a navigation process. One may consider that an overview diagram may be helpful tool only when we are lost. Understanding when information is needed will lead to designing for utilize a space of display screen. The role of the user interface in navigation forms the substance of section 4. What class of user interface will be suitable for navigation and why? There are many comparative studies of interfaces in terms of navigation. However, the many options in designing create an immense number of possibilities. Comparing all of those designs may be not possible. It might be possible to classify interfaces into classes by some specific dimensions. The comparison within the same class and among classes will show the effects of those dimensions. Finally, section 5 discusses the issues associated with integrating navigation tools. What if we have two navigation tools presented? Will both of them be used or will one dominate the navigation process? Do multiple windows with a certain presentation perform better than windows used in changing mode condition, i.e. integration in time? In the integrated environment, a document may be presented in several place, cohesion of presenting may be significant for understanding a relation between tools. Download 324.2 Kb. Share with your friends:
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