Synchronization Algorithms on Oriented Chains

We present a space- and time-optimal self-stabilizing algorithm, SSDS, for a given synchronization problem on asynchronous oriented chains. SSDS is uniform and works under the unfair distributed daemon. From SSDS we derive solutions for the local mutual exclusion and distributed sorting. Algorithm SSDS can also be used to obtain optimal space solutions for other problems such as broadcasting, leader election, and mutual exclusion

Annotating Relationships between Multiple Mixed-media Digital Objects by Extending Annotea

Annotea provides an annotation protocol to support collaborative Semantic Web-based annotation of digital resources accessible through the Web. It provides a model whereby a user may attach supplementary information to a resource or part of a resource in the form of: either a simple textual comment; a hyperlink to another web page; a local file; or a semantic tag extracted from a formal ontology and controlled vocabulary. Hence, annotations can be used to attach subjective notes, comments, rankings, queries or tags to enable semantic reasoning across web resources. More recently tabbed Browsers and specific annotation tools, allow users to view several resources (e.g., images, video, audio, text, HTML, PDF) simultaneously in order to carry out side-by-side comparisons. In such scenarios, users frequently want to be able to create and annotate a link or relationship between two or more objects or between segments within those objects. For example, a user might want to create a link between a scene in an original film and the corresponding scene in a remake and attach an annotation to that link. Based on past experiences gained from implementing Annotea within different communities in order to enable knowledge capture, this paper describes and compares alternative ways in which the Annotea Schema may be extended for the purpose of annotating links between multiple resources (or segments of resources). It concludes by identifying and recommending an optimum approach which will enhance the power, flexibility and applicability of Annotea in many domains

Efficient Optimal Pagination of Scrolls

Diehr and Faaland developed an algorithm that finds the minimum sum of key length pagination of a scroll of n items, and which uses O(n log n) time solving a problem posed by McCreight. An improved algorithm is given which uses O(n) tim

The Traveler's Problem

The Traveler's Problem (TP) entails determining the maximum distance that can be traversed along a road, given the locations and room rates of inns along that road, and given the constraints of maximum distance per day and limited budget available for overnight stays at inns. An O#(n 3 5 _ (log n) 3 1 _ ) time algorithm is presented for the TP. An O#(n 3 5 _ (log n) 3 4 _ )-time algorithm for computing a minimum height B-tree for a dictionary of length n is given, by reducing the problem to O#(log n) instances of the TP. 1. Introduction In this paper, we describe and solve the Traveler's Problem. Suppose a traveler must journey along a road on which there are located various inns, each charging different room rates. The traveler must stop at an inn each night, and pay the cost of that inn out of his limited budget. (He need not pay for an inn at his start or destination.) There is a further restriction on how far the traveler can travel in one day. We assume that the inns are s..

Average Case Analysis of Marking Algorithms

. The Lindstrom marking algorithm uses bounded workspace. Its time complexity is O(n 2 ) in all cases, but it has been assumed that the average case time complexity is O(n lg n). It is proven that the average case time complexity is Q(n 2 ). Similarly, the average size of the Wegbreit bit stack is shown to be Q(n). Key words. Lindstrom, garbage collection, marking algorithm. ------------------------ This research was supported in part by National Science Foundation Grant MCS-82-00362, and by a California State University PAID grant. + Department of Information and Computer Science, University of California, Irvine, CA 92717. # Department of Computer Science, California State University, Dominguez Hills, CA 94707. Average Case Analysis of Marking Algorithms D.S. Hirschberg + and L.L. Larmore # University of California, Irvine California State University, Dominguez Hills 1. Introduction Consider a data store organized into nodes, each of which has two link fields, L and R...

The Knuth-Yao quadrangle-inequality speedup is a consequence of total-monotonicity

There exist several general techniques in the literature for speeding up naive implementations of dynamic programming. Two of the best known are the Knuth-Yao quadrangle inequality speedup and the SMAWK algorithm for finding the row-minima of totally monotone matrices. Although both of these techniques use a quadrangle inequality and seem similar they are actually quite different and have been used differently in the literature. In this paper we show that the Knuth-Yao technique is actually a direct consequence of total monotonicity. As well as providing new derivations of the Knuth-Yao result, this also permits showing how to solve the Knuth-Yao problem directly using the SMAWK algorithm. Another consequence of this approach is a method for solving online versions of problems with the Knuth-Yao property. The online algorithms given here are asymptotically as fast as the best previously known static ones. For example the Knuth-Yao technique speeds up the standard dynamic program for finding the optimal binary search tree of n elements from ⊖(n 3) down to O(n 2), and the results in this paper allow construction of an optimal binary search tree in an online fashion (adding a node to the left or right of the current nodes at each step) in O(n) time per step. We conclude by discussing how the general technique described here is also applicable to later extensions of the Knuth-Yao result, such as those devel oped by Borchers and Gupta