We present a new purity and side effect analysis for Java programs. A method is pure if it does not mutate any location that exists in the program state right before the invocation of the method. Our analysis is built on top of a combined pointer and escape analysis, and is able to determine that methods are pure even when the methods mutate the heap, provided they mutate only new objects. Our ...

The incident and problem management process forms an essential part in every organization. Since businesses rely heavily on IT, each outage, issue or user service request should be dealt with as quickly as possible in order to minimize its impact on operations. For Volvo IT Belgium, we analyzed the event log file of an incident and problem management system called VINST, in order to objectively...

Given a simple polygon P consisting of n vertices, we study the problem of designing space-efficient algorithms for computing (i) the visibility polygon of a point inside P , (ii) the weak visibility polygon of a line segment inside P and (iii) the minimum link path between a pair of points inside P . For problem (i) two algorithms are proposed. The first one is an in-place algorithm where the ...

This paper discusses the design and implementation of SDC, a new caching strategy aimed to efficiently exploit the locality present in the stream of queries submitted to a Web Search Engine. SDC stores the results of the most frequently submitted queries in a fixed-size read-only portion of the cache, while the queries that cannot be satisfied by the static portion compete for the remaining ent...

We consider the read/write streams model, an extension of the standard data stream model in which an algorithm can create and manipulate multiple read/write streams in addition to its input data stream. Like the data stream model, the most important parameter for this model is the amount of internal memory used by such an algorithm. The other key parameters are the number of streams the algorit...

In this paper we present StarFish, a highly-available geographically-dispersed block storage system built from commodity servers running FreeBSD, which are connected by standard high-speed IP networking gear. StarFish achieves high availability by transparently replicating data over multiple storage sites. StarFish is accessed via a host-site appliance that masquerades as a host-attached storag...

Testing two-port memories requires the use of single-port tests as well as special two-port tests; the test strategy determines which tests have to be used. Many two-port memories have ports which are read-only or write-only; this impacts the possible tests for single-port and two-port memories, as well as the test strategy. This paper discusses the consequences of the port restrictions (read-o...

Fault-tolerance has long been a feature of database systems, with transactions supporting the structuring of applications so as to ensure continuation of updating applications in spite of machine failures. For read-only queries the perceived wisdom has been that support for faulttolerance is too expensive to be worthwhile. Distributed query processing (DQP) is coming to be seen as a promising w...

The conjectured hardness of Boolean matrix-vector multiplication has been used with great success to prove conditional lower bounds for numerous important data structure problems, see Henzinger et al. [STOC’15]. In recent work, Larsen and Williams [SODA’17] attacked the problem from the upper bound side and gave a surprising cell probe data structure (that is, we only charge for memory accesses...