Classifications have been used for centuries with the goal of cataloguing and searching large sets of objects. In the early days it was mainly books; lately it has also become Web pages, pictures and any kind of electronic information items. Classifications describe their contents using natural language labels, which has proved very effective in manual classification. However natural language l...

Collaborative navigation systems provide a useful way for virtual groups to share information through the web. However, the common set of features of these tools is not enough to offer a more face-to-face-like browsing experience. To fill this gap, this paper presents a novel collaborative web browsing proposal, which aims at integrating notably flexible management of sessions, the maintenance ...

λProlog is known to be well-suited for expressing and implementing logics and inference systems. We show that lemmas and definitions in such logics can be implemented with a great economy of expression. The terms of the meta-language (λProlog) can be used to express the statement of a lemma, and the type checking of the metalanguage can directly implement the type checking of the lemma. The ML-...

Angelos d. Keromytis is an Associate Professor of computer Science at columbia University. His research interests revolve around systems and software security and reliability. He received his Phd in 2001 from the University of Pennsylvania. [email protected] Kernel exploits have become increasingly popular over the past several years. We have developed kGuard, a cross-platform system that...

Text is a popular storage and distribution format for information, partly due to generic text-processing tools like Unix grep and sort. Unfortunately, existing generic tools make assumptions about text format (e.g., each line is a record) that limit their applicability. Custom-built tools are one alternative, but they require substantial time investment and programming expertise. We describe a ...

In order to design parallel applications that exploit efficiently modern supercomputers with their complex architecture, it is required to apply a variety of programming models and techniques. The development of such applications as well as their tuning to achieve the optimal performance is practically impossible without performance analysis tools. In this paper, we present a scalable binary tr...

Within an effort for providing a layered architecture of services supporting multi-peer collaborative applications, this paper proposes a new type of consistency management aimed for applications where a large number of processes share a large set of replicated objects. Many such applications, like peer-to-peer collaborative environments for training or entertaining purposes, platforms for dist...

In this paper, to match a lightweight digital signing scheme of which the length of modulus is between 80 and 160 bits, a lightweight hash function called JUNA is proposed. It is based on the intractabilities MPP and ASPP, and regards a short message or a message digest as an input which is treated as only one block. The JUNA hash contains two algorithms: an initialization algorithm and a compr...

We describe an implementation of a threads library that provides extremely lightweight threads within a single UNIX process while allowing fully concurrent access to system resources. The threads are lightweight enough so that they can be created quickly, there can be thousands present, and synchronization can be accomplished rapidly. These goals are achieved by providing user threads which mul...