It has been a recognized fact for many years that query execution can benefit from pushing group-by operators down in the operator tree and applying them before a join. This so-called eager aggregation reduces the size(s) of the join argument(s), making join evaluation faster. Lately, the idea enjoyed a revival when it was applied to outer joins for the first time and incorporated in a state-of...

The similarity join is an important database primitive which has been successfully applied to speed up applications such as similarity search, data analysis and data mining. The similarity join combines two point sets of a multidimensional vector space such that the result contains all point pairs where the distance does not exceed a given Parameter ε. Although the similarity join is clearly CP...

If a space-time with a causal relationship is viewed from an observer in space-time, the interaction between space-time and the observer has to be implemented. We describe this interaction using a pair of causal sets and its semantics or using a pair of Point and Open Logic. We here propose an artificial causal space-time called an evolutionary topological system, which is based on the changeab...

In this paper we start with a lattice (X,∨,∧) and define, in terms of ∨, a family of crisp hyperoperations tp (one hyperoperation for each p ∈ X). We show that, for every p, the hyperalgebra (X,tp) is a join space and the hyperalgebra (X,tp,∧) is very similar to a hyperlattice. Then we use the hyperoperations tp as p-cuts to introduce an L-fuzzy hyperoperation t and show that (X,t) is an L-fuzz...

Many parallel join algorithms have been proposed so far but most of which are developed focused on minimizing the disk I t 0 and CPU costs. The communication cost, however, is also an important factor that can significantly affect the join processing performance in multiprocessor system. In this paper we propose an eficient parallel join algorithm, called CubeRobust, for hypercube multicomputer...

In this paper, we study a single server Markovian queue with state dependent accessible services, reneging and feedback of customers. The server can accommodate at the most $d$ customers in the service station, after which the new arrivals have to wait in the primary queue of infinite waiting space. All arrivals demand First Essential Service (FES), after completing FES, customers decide to joi...