For a DBMS that provides support for a declarative query language like SQL, the query optimizer is a crucial piece of software. The declarative nature of a query allows it to be translated into many equivalent evaluation plans. The process of choosing a suitable plan from all alternatives is known as query optimization. The basis of this choice are a cost model and statistics over the data. Ess...

We define contact fiber bundles and investigate conditions for the existence of contact structures on the total space of such a bundle. The results are analogous to minimal coupling in symplectic geometry. The two applications are construction of K-contact manifolds generalizing Yamazaki’s fiber join construction and a cross-section theorem for contact moment maps.

This paper proposes a multi-objective genetic algorithm to optimize a manipulator trajectory. The planner has several objectives namely the minimization of the space and join arm displacements and the energy required in the trajectory, without colliding with any obstacles in the workspace. Simulations results are presented for robots with two and three degrees of freedom, considering the optimi...

The growing size of Semantic Web data expressed in the form of Resource Description Framework (RDF) has made it necessary to develop effective ways of storing this data to save space and to query it in a scalable manner. SPARQL – the query language for RDF data – closely follows SQL syntax. As a natural consequence most of the RDF storage and querying engines are based on modern database storag...

Due to advances in computer technology, many organizations have a large number of workstation-class machines connected by LAN. Such a network of workstations (NOW) can be used for parallel processing, including database query processing. This paper proposes a new load sharing algorithm for hash join processing on NOWs. This new algorithm combines a chunking method with hash join to manage dynam...

Concatenative Text-to-Speech (TTS) systems such as those described by Hunt and Black [6] can select at synthesis time from a very large number of recorded units. The selected units are chosen to minimize a combination of target and join costs for a given sentence. However, the join costs, in particular, can be quite expensive to compute, even when this computation has been optimized. If possibl...

We introduce the proximity rank join problem, where we are given a set of relations whose tuples are equipped with a score and a real-valued feature vector. Given a target feature vector, the goal is to return the K combinations of tuples with high scores that are as close as possible to the target and to each other, according to some notion of distance or dissimilarity. The setting closely res...

The cyclicity of a hypergraph is an e ciently computable integer that extends the notion of the cyclomatic number of a graph The formula for the cyclicity is suggested by the join invariant of an acyclic hypergraph which is the multiset of all joining sets in any of its join trees Once we gure out how the multiplicity of a joining set depends on the structure of the acyclic hypergraph we de ne ...

DEFINITION Spatial join operation is used to combine two or more datasets with respect to a spatial predicate. The predicate can be a combination of directional, distance, and topological spatial relations. In the case of nonspatial joins, the joining attributes must be of the same type, but for spatial joins they can be of different types. Usually each spatial attribute is represented by its m...