The performance of a non-standard distributed database system is strongly influenced by complex objects. The effective exploitation of parallelism in querying them and a suitable structure to store them are required in order to obtain acceptable response times in these database environments where performance tends to be critical. In this paper we use an hierarchical complex object model with ob...

Real-world data are often uncertain and incomplete. In probabilistic relational data models uncertainty can be modeled on two levels. First by representing the uncertain instance of a tuple by a set of possible instances and second by assigning each tuple with its degree of membership to the considered relation. To overcome incompleteness, data from multiple sources need to be combined. In orde...

Let k be a positive integer. A subset S of V (G) in a graph G is a k-tuple total dominating set of G if every vertex of G has at least k neighbors in S. The k-tuple total domination number γ×k,t(G) of G is the minimum cardinality of a k-tuple total dominating set of G. In this paper for a given graph G with minimum degree at least k, we find some sharp lower and upper bounds on the k-tuple tota...

The notion of critical tuple was introduced by Miklau and Suciu [2], who also claimed that the problem of checking whether a tuple is non-critical is Πp2-complete. Kostylev identified an error in the 12-page-long hardness proof. It turns out that the issue is rather fundamental: the proof can be adapted to show hardness of a relative variant of tuple-non-criticality, but we have neither been ab...

The paper describes the design and the Java implementation of a coordination architecture for mobile agents, based on an object-oriented Linda-like tuple space model, compliant with the Sun's JavaSpaces specifications. Moreover, unlike Linda and JavaSpaces, the proposed architecture integrates a reactive model: the behaviour of the tuple spaces can be programmed by installing reactions which ar...

Because of the complexity of decision-making environment, the uncertainty of fuzziness and the uncertainty of grey maybe coexist in the problems of multi-attribute group decision making. In this paper, we study the problems of multi-attribute group decision making with hybrid grey attribute data (the precise values, interval numbers and linguistic fuzzy variables coexist, and each attribute val...

Let us assume that these two agents are accessing the same tuple space, and that no other agents are able to access the tuple space, and that the tuple space contains two tuples, a and b. The case graph for these agents is shown in Figure 1. As can be seen, there is no case where both Agent A and B complete, either one or both block waiting for a matching A1:in(a) A2:rd(b) B1:in(b) B2:rd(a) B1:...

We introduce tuple cryptanalysis, a variant of structural cryptanalysis techniques as square, saturation, integral, internal collision, or multiset cryptanalysis, the main difference being that tuple cryptanalysis considers ordered rather than unordered multisets. This allows cryptanalysts to better trace structural properties within a cipher’s internal state. Unlike previous works that focus o...

ABSTRACT: Linda1 is a model for parallel processing based on distributed data structures. Processors and data objects communicate by means of the tuple space (TS) or Linda memory. The interaction between the tuple space and the processors is carried out by four basic operations: out, in, eval, and rd. These operations add/remove/read data objects from/to the tuple space . eval on the other hand...

This demonstration showcases the STEP system for natural language access to relational databases. In STEP an administrator authors a highly structured semantic grammar through coupling phrasal patterns to elementary expressions within a decidable fragment of tuple relational calculus. The resulting phrasal lexicon serves as a bi-directional grammar, enabling the generation of natural language f...