16512886
Opportunities for data base reorganization
If the contents of the data base are volatile, automating the process does not eliminate the need for reorganization. In fact, the minor inefficiencies which could be tolerated with small files are a costly burden in the massive data bases which are increasingly common. There are numerous techniques for improving data base performance; this paper is concerned with the process known as reorganization. Reorganization is the rewriting of fields of data in such a way that the logical and physical accessing algorithms are unaffected (although the access paths may be altered) except that they now operate more economically. Economics include saving of storage space or execution time or both. In on-line systems there is the additional motivation of reducing the response time.
6042127
Colour‐coded pixel‐based highly interactive Web mapping for georeferenced data exploration
This paper describes a pixel‐based technique that enables highly interactive Web choropleth maps for georeferenced data publishing and visual exploration. Instead of delivering geographic knowledge to the client in polygon‐based vector formats, we encode geographic object IDs and shape information into highly compact pixel images (decoding maps). This allows the combination of raster and vector characteristics while avoiding the problems in the currently existing pixel‐based (raster‐image‐based) or vector‐based techniques. Differing from traditional pixel‐based techniques that are static and allow very little user interaction, our pixel‐based technique allows varieties of sub‐second (less than 1 s) interface controls such as dynamic query, dynamic classification, geographic object data identification, user‐setting adjusting, as well as turning on/off layers, panning and zooming, with no or minimum server support. Compared with Web GIS techniques that use vector geographic data, our technique avoids transferring over the network large vector geographic data. It also avoids the non‐trivial client‐side computation to interpret the vector data and render the maps. Our technique features a short initial download time, near‐constant performance scalability for larger numbers of geographic objects, and download‐map‐segment‐only‐when‐necessary which potentially reduces the overall data transfer over the network. As a result, it accommodates general public users with slow modem network connections and low‐end machines, as well as users with fast T‐1 connections and fast machines. The client‐side (browser) is implemented as lightweight Java applets. YMap, an easy‐to‐use, user‐task‐oriented highly interactive mapping tool for visual georeferenced data exploration is implemented using this technique. The performance comparison of YMap to some other vector‐based Web GIS demonstrates the feasibility and benefits of this technique.
14787313
ACM's computing professionals face new challenges
Technologists can make a difference on so many critical fronts.
12355336
Direct annotation: a drag-and-drop strategy for labeling photos
Annotating photographs is such a time-consuming, tedious and error-prone data entry task that it discourages most owners of personal photo libraries. By allowing the user to drag labels, such as personal names, from a scrolling list and drop them onto a photo, we believe we can make the task faster, easier and more appealing. Since the names are entered in a database, searching for all photos of a friend or family member is dramatically simplified. We describe the user interface design and the database schema to support direct annotation, as implemented in our PhotoFinder prototype.
8937545
Universal usability
see knowledge so disseminated through the mass of mankind that it may…reach even the extremes of society: beggars and kings.
44345836
Path Expressions for Complex Queries and Automatic Database Program Conversion
Our efforts to develop an automatic database system conversion facility yielded a powerful, yet simple query language which was designed for ease of conversion. The path expression of this query language is a convenient and appealing notation for describing complex traversals with multiple boolean qualifications. This paper describes the path expression, shows how automatic conversions can be done, introduces the boolean functions as part of the basic path expression, offers four extensions (path macros, implied path, path replacement, and path optimization), and discusses some implementation issues.
26554081
Structural analysis of hypertexts: identifying hierarchies and useful metrics
Hypertext users often suffer from the “lost in hyperspace” problem: disorientation from too many jumps while traversing a complex network. One solution to this problem is improved authoring to create more comprehensible structures. This paper proposes several authoring tools, based on hypertext structure analysis.
In many hypertext systems authors are encouraged to create hierarchical structures, but when writing, the hierarchy is lost because of the inclusion of cross-reference links. The first part of this paper looks at ways of recovering lost hierarchies and finding new ones, offering authors different views of the same hypertext. The second part helps authors by identifying properties of the hypertext document. Multiple metrics are developed including compactness and stratum. Compactness indicates the intrinsic connectedness of the hypertext, and stratum reveals to what degree the hypertext is organized so that some nodes must be read before others.
Several existing hypertexts are used to illustrate the benefits of each technique. The collection of techniques provides a multifaceted view of the hypertext, which should allow authors to reduce undesired structural complexity and create documents that readers can traverse more easily.
36247121
Navigating in hyperspace: designing a structure-based toolbox