In this paper, we examine the inherent properties of some of the most popular coordination models of today and show how they contribute to the difficulty of systematic construction of coordination protocols for the cooperation of concurrent processes, as explicit, tangible pieces of software. They include the object oriented models of communication and the generative tuple space paradigm of mod...

Space and time are key elements for many computer-based systems often elevated to first-class abstractions. In tuple-based coordination, Linda primitives have been independently extended with space (with tuples queries spanning spatial regions) or information (mostly tuple scoping). However, recent works in collective adaptive aggregate computing show that can naturally be considered as two int...

This report introduces the STEP system for natural language access to relational databases. In contrast to most work in the area, STEP adopts a phrasal approach; an administrator couples phrasal patterns to elementary expressions of tuple relational calculus. This ‘phrasal lexicon’ is used bi-directionally, enabling the generation of natural language from tuple relational calculus and the inver...

In a graph G, a vertex is said to dominate itself and all of its neighbors. For a fixed positive integer k , the k-tuple domination problem is to find a minimum sized vertex subset such that every vertex in the graph is dominated by at least k vertices in this set. The present paper studies the k-tuple domination problem in graphs from an algorithmic point of view. In particular, we give a line...

We present a probabilistic data model which is based on relations in non-rst-normal-form (NF2). Here, tuples are assigned probabilistic weights giving the probability that a tuple belongs to a relation. This way, imprecise attribute values are modelled as a probabilistic subrelation. For information retrieval, the set of weighted index terms of a document can be represented in the same way, thu...

Guaranteed tuple processing has become critically important for many streaming applications. This paper describes how we enabled IBM Streams, an enterprise-grade stream processing system, to provide data processing guarantees. Our solution goes from language-level abstractions to a runtime protocol. As a result, with a couple of simple annotations at the source code level, IBM Streams developer...

In this paper we describe the Cambridge Collaborative Agent System (C2AS). This is a prototype system designed to demonstrate the functionality and basic architecture of a framework for co-ordination between different components (or agents) of distributed ‘Web’ applications. Co-ordination in C2AS is achieved through the use of tuple spaces, as used in Linda. However, the access primitives used ...

The existing approaches of keyword search over relational databases always identify the relationships between tuples on the fly, which are rather inefficient as such relational relationships are very rich in the underlying databases. Alternatively, this paper proposes an alternative way by retrieving and materializing tuple units for facilitating the online processing of keyword search. We firs...