Results

**11 - 14**of**14**### An Optimal Dynamic Data Structure for Stabbing-Semigroup Queries ∗

"... Let S be a set of n intervals in R, and let (S,+) be any commutative semigroup. We assign a weight ω(s) ∈ S to each interval in S. For a point x ∈ R, let S(x) ⊆ S be the set of intervals that contain x. Given a point q ∈ R, the stabbing-semigroup query asks for ω(s). We propose a linear-size dynam ..."

Abstract
- Add to MetaCart

Let S be a set of n intervals in R, and let (S,+) be any commutative semigroup. We assign a weight ω(s) ∈ S to each interval in S. For a point x ∈ R, let S(x) ⊆ S be the set of intervals that contain x. Given a point q ∈ R, the stabbing-semigroup query asks for ω(s). We propose a linear-size dynamic data structure, under the pointermachine model, that answers queries in worst-caseO(logn) time, and supports both insertions and deletions of intervals in amortized O(logn) time. It is the first data structure that attains the optimal O(logn) bound for all three operations. Furthermore, our structure can easily be adapted to external memory, where we obtain a linear-size structure that answers queries and supports updates inO(logB n) I/Os, where B is the disk block size. For the restricted case of nested family of intervals (every pair of intervals are either disjoint or one contains the other), we present a simpler solution based on dynamic trees. computing ∑ s∈S(q) 1

### ANALYSIS THROUGH REFLECTION: WALKING THE EMF MODEL OF BPEL4WS

, 2005

"... In this thesis, we review different approaches to implement analyses for the Busi-ness Process Execution Language for Web Services (BPEL4WS) — a language initially proposed by BEA, IBM and Microsoft to describe business process be-haviour based on web services. Analyses of a BPEL4WS program often b ..."

Abstract
- Add to MetaCart

In this thesis, we review different approaches to implement analyses for the Busi-ness Process Execution Language for Web Services (BPEL4WS) — a language initially proposed by BEA, IBM and Microsoft to describe business process be-haviour based on web services. Analyses of a BPEL4WS program often boil down to walking the abstract syntax tree of the program. We exploit the Eclipse Mod-elling Framework (EMF) to generate a hierarchy of Java classes and interfaces that represents the abstract syntax of BPEL4WS. We review, refine and extend a technique, based on Java’s reflection mechanism and introduced by Palsberg and Jay [44], to walk such trees. Such a walker provides us a powerful approach to analyze BPEL4WS programs. Unfortunately, since the walker relies on Java’s reflection mechanism, its performance is rather poor. A significant part of our research has focused on improving its performance. Caching the results of Java’s reflection as proposed by Bravenboer and Visser [9] and also by Forax and Rous-sel [25], and generating new code, at run time, to replace calls to Java’s reflection

### Tradeoffs for Packet Classification

"... Abstract—We present an algorithmic framework for solving the packet classification problem that allows various access time vs. memory tradeoffs. It reduces the multi-dimensional packet classification problem to solving a few instances of the one-dimensional IP lookup problem. It gives the best known ..."

Abstract
- Add to MetaCart

Abstract—We present an algorithmic framework for solving the packet classification problem that allows various access time vs. memory tradeoffs. It reduces the multi-dimensional packet classification problem to solving a few instances of the one-dimensional IP lookup problem. It gives the best known lookup performance with moderately large memory space. Furthermore, it efficiently supports a reasonable number of additions and deletions to the rulesets without degrading the lookup performance. We perform a thorough experimental study of the tradeoffs for the two-dimensional packet classification problem on rulesets derived from datasets collected from AT&T WorldNet, an Internet Service Provider. I.

### Dictionary Matching and Indexing with Errors and Don't Cares*

"... Abstract This paper considers various flavors of the following online problem: preprocess a text orcollection of strings, so that given a query string p, all matches of p with the text can be reportedquickly. In this paper we consider matches in which a bounded number of mismatches are allowed,or in ..."

Abstract
- Add to MetaCart

Abstract This paper considers various flavors of the following online problem: preprocess a text orcollection of strings, so that given a query string p, all matches of p with the text can be reportedquickly. In this paper we consider matches in which a bounded number of mismatches are allowed,or in which a bounded number of &quot;don't care &quot; characters are allowed. The specific problems we look at are: indexing, in which there is a single text t, and we seeklocations where p matches a substring of t; dictionary queries, in which a collection of stringsis given upfront, and we seek those strings which match p in their entirety; and dictionarymatching, in which a collection of strings is given upfront, and we seek those substrings of a (long) p which match an original string in its entirety. These are all instances of an all-to-allmatching problem, for which we provide a single solution. The performance bounds all have a similar character. For example, for the indexing problem with n = |t | and m = |p|, the query time for k substitutions is O(m + (c1 log n) k