Paul F. Dietz

Optimal Algorithms for List Indexing and Subset Rank

Fredman and Saks [1] have proved a Ω(log n/log log n) amortized time lower bound for two problems, List Indexing and Subset Rank, in the cell probe model with logarithmic word size. This paper gives algorithms for both problems that achieve the lower bound on a RAM with logarithmic word size.

Fully persistent arrays

This paper has outlined an algorithm for fully persistent arrays in which Access operations take O(log log n) time and Store operations take O(log log n) amortized expected time. The algorithm uses linear space.

Lower Bounds for Monotonic List Labeling

We present optimal lower bound for special cases of the list labeling problem. This problem has diverse practical applications, including implementation of persistent data structures, in the incremental evaluation of computational circuits and in the maintenance of dense sequential files. We prove, under a reasonable restriction on the algorithms, that Ω(n log2n) relabelings are necessary when inserting n items into list monotonically labeled from a label space of size O(n). We also prove that Ω(n log n) relabelings are required in the case of a label space of polynomial size.

A Tight Lower Bound for On-line Monotonic List Labeling

Maintaining a monotonic labeling of an ordered list during the insertion of n items requires \Omega (n log n) individual relabelings in the worst case, if the number of usable labels is only polynomial in n. This follows from a lower bound for a new problem, prefix bucketing.

Bits and Relative Order from Residues, Space Efficiently

For each k, let P_k be the product of the first k primes. By the Chinese remainder theorem, each integer in the interval [0, P_k) is determined by its residues modulo these k primes. We address the problems of space-efficiently computing the bits and the relative order of such numbers from their residues.

A constant update time finger search tree

Levcopolous and Overmars [12] describe a search tree in which the time to insert or delete a key is O(1) once the position of the key to be inserted or deleted was known. Their data structure does not support fingers, pointers to points of high access or update activity in the set such that access and update operations in the vicinity of a finger are particularly efficient [3, 8, 10, 11, 15]. Levcopolous and Overmars leave as an open question whether a data structure can be designed which allowed updates in constant time and supports fingers. We answer the question in the affirmative by giving an algorithm in the RAM with logarithmic word size model [1].

Experiences in deploying model-driven engineering

In this paper, we describe how Motorola has deployed model-driven engineering in product development, in particular for the development of highly reliable telecommunications systems, and outline the benefits obtained. Model-driven engineering has dramatically increased both the quality and the reliability of software developed in our organization, as well as the productivity of our software engineers. Our experience demonstrates that model-driven engineering significantly improves the development process for telecommunications systems. We discuss the elements we found most important for deployment of model-driven engineering in a large product development organization: An appropriate modeling language, a powerful domain-specific code generator, and a deployment support team.

A Tight Lower Bound for Online Monotonic List Labeling

Maintaining a monotonic labeling of an ordered list during the insertion of n items requires

Lower bounds for set intersection queries

\Omega

Heap Construction in the Parallel Comparison Tree Model

(n log n) individual relabelings, in the worst case, if the number of usable labels is only polynomial in n. This follows from a lower bound for a new problem, prefix bucketing.