Trying to find information on the Web is like trying to find something at a jumble sale: it is fun, and you can make serendipitous discoveries, but for directed search it is better to go to a department store; there, someone has already done most of the arranging for you. Unfortunately, the Web's continuing explosion in size, its enormous diversity of topics, and its great volatility, make unaided human indexing impossible. This problem is just a special case of the general problem of organizing information to create knowledge. A similar problem arises on the desktop when dealing with file systems, where users must search by name. When searching for a particular file, however, users often do not remember the file's name or location. File names are artifacts of current operating systems, but human understanding neither requires objects to be named, nor does it have problems with multiple objects sharing properties, names, for instance. That more general approach is not developed in current file systems or user interfaces. We argue for an approach to information representation based on the use of attributes and search. This representation is organization-neutral, thereby giving a flexible substrate for anyone to build multiple simultaneous organizations. We argue the approach from three perspectives: Attribute Value System (AVS), a networked storage system where objects are composed solely of attribute-value pairs; DomainView (DV), a desktop metaphor where objects do not have explicit names and retrieval is done by content; and KnownSpace (KS), a personalized desktop data manager.

The matrix chain ordering problem is to find the cheapest way to multiply a chain of n matrices, where the matrices are pairwise compatible but of varying dimensions. Here we give several new parallel algorithms including $O(\lg^3 n)$-time and $n/\!\lg n$-processor algorithms for solving the matrix chain ordering problem and for solving an optimal triangulation problem of convex polygons on the common CRCW PRAM model. Next, by using efficient algorithms for computing row minima of totally monotone matrices, this complexity is improved to $O(\lg^2 n)$ time with n processors on the EREW PRAM and to $O(\lg^2 n \lg \lg n)$ time with $n/ \! \lg \lg n$ processors on a common CRCW PRAM\@. A new algorithm for computing the row minima of totally monotone matrices improves our parallel MCOP algorithm to $O(n \lg^{1.5} n)$work and polylog time on a CREW PRAM\@. Optimal log-time algorithms for computing row minima of totally monotone matrices will improve our algorithm and enable it to have the same work as the sequential algorithm of Hu and Shing [SIAM J. Comput., 11 (1982), pp. 362--373; SIAM J. Comput., 13 (1984), pp. 228--251].

This article examines the future of the book publishing industry and presents strategies for publishers to decrease risk and increase profit. These strategies also benefit education, science, and technology by making books cheaper, more flexible, and more easily and quickly available. © 1993 John Wiley & Sons, Inc.

Given a set of n rectangles with sides parallel to the coordinate axes, we show how to determine whether their union, viewed as a set of disjoint polygons, has a hole. The algorithm presented needs no more than $O( n\log n )$ time and $O( n )$ space, which is shown to be optimal. However, in practice it is also necessary to know the locations of holes, if there are any. We present an algorithm to determine the locations of all h holes in $O( n\log n + h )$ time and $O( n )$ space, which is again optimal. The algorithm computes a point within each hole, representing the location of the hole. The efficiency of these and several other algorithms follows from some simple combinatorial arguments about sets of rectangles in the plane.

In this paper we present an algorithm to create simple polygons with a particular sequence of exterior angles, given only the sequence of angles. The algorithm has worst case time complexity Ο(Dn), where n is the number of angles and D is dependent on the angles. As a bonus, the algorithm proves an interesting converse of the ancient theorem that the sum of the exterior angles of a simple polygon is 2π radians.