Daniel P. Miranker

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Learning during backtrack search is a space-intensive process that records information (such as additional constraints) in order to avoid redundant work. In this paper, we analyze the effects of polynomial-spacebounded learning on runtime complexity of backtrack search. One space-bounded learning scheme records only those constraints with limited size, and(More)
We develop a theoretical framework to characterize the hardness of indexing data sets on block-access memory devices like hard disks. We define an indexing workload by a data set and a set of potential queries. For a workload, we can construct an indexing scheme, which is a collection of fixed-sized subsets of the data. We identify two measures of(More)
The Semantic Web’s promise to achieve web-wide data integration requires the inclusion of legacy relational data as RDF, which, in turn, requires the execution of SPARQL queries on the legacy relational database. In this paper we explore a hypothesis: existing commercial relational databases already subsume the algorithms and optimizations needed to support(More)
Mapping relational databases to RDF is a fundamental problem for the development of the Semantic Web. We present a solution, inspired by draft methods defined by the W3C where relational databases are directly mapped to RDF and OWL. Given a relational database schema and its integrity constraints, this direct mapping produces an OWL ontology, which,(More)
We examine the organizational impact on phylogenetic databases of the increasing sophistication in the need and use of phylogenetic data. A primary issue is the use of the unnormalized representation of phylogenies in Newick format as a primitive data type in existing phylogenetic databases. In particular, we identify and enumerate a list of potential(More)
Production systems are an established method for encoding knowledge in an expert system. The semantics of production system languages and the concomitant algorithms for their evaluation, RETE and TREAT, enumerate the set of rule instantiations and then apply a strategy that selects a single instantiation for firing. Often rule instantiations are calculated(More)
Performance issues often prevent prototype production system programs from scaling to large deliverable systems. In this paper, we wiU describe an ensemble of techniques that compile OPS5 production system programs to executable machine code and demonstrate an increase in the execution speed of production system programs by two orders of magnitude over the(More)
Building practical expert database systems requires an effective inferencing capability over large data sets. rnferencing in this context means repeatedly executing a fixed set of queries, interleaved with update transactions, until a fix:3 pint is reached. The effectiveness of ,.lircncing mechanism is heavily depcnde; !:on :he amount of state space needed(More)
A common technique for bounding the runtime required to solve a constraint satisfaction problem is to exploit the structure of the problem's constraint graph [Dechter, 92]. We show that a simple structure-based technique with a minimal space requirement, pseudo-tree search [Freuder & Quinn, 85], is capable of bounding runtime almost as effectively as the(More)