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Citation graphs representing a body of scientific literature convey measures of scholarly activity and productivity. In this work we present a study of the structure of the citation graph of the computer science literature. Using a web robot we built several topic-specific citation graphs and their union graph from the digital library ResearchIndex. After(More)
In many applications it is important to find a meaningful relationship between the schemas of a source and target database. This relationship is expressed in terms of declarative logical expressions called schema mappings. The more successful previous solutions have relied on inputs such as simple element correspondences between schemas in addition to local(More)
[1] We conducted two experiments, one long term with a 2 C increase (Experiment 1) and one short term with a 4.4 C increase (Experiment 2), to investigate main and interactive effects of warming, clipping, and doubled precipitation on soil CO2 efflux and its temperature sensitivity in a U.S. tallgrass prairie. On average, warming increased soil CO2 efflux(More)
There are many problems requiring a semantic account of a database schema. At its best, such an account consists of mapping formulas between the schema and a formal conceptual model or ontology (CM) of the domain. This paper describes the underlying principles, algorithms, and a prototype of a tool which infers such semantic mappings when given simple(More)
Much data is published on the Web in XML format satisfying schemas, and to make the Semantic Web a reality, such data needs to be interpreted with respect to ontologies. Interpretation is achieved through a semantic mapping between the XML schema and the ontology. We present work on the heuristic construction of complex such semantic mappings, when given an(More)
A recent special issue of AI Magazine (AAAI 2005) was dedicated to the topic of semantic integration — the problem of sharing data across disparate sources. At the core of the solution lies the discovery the “semantics” of different data sources. Ideally, the semantics of data are captured by a formal ontology of the domain together with a semantic mapping(More)
This paper describes a hidden Markov model (HMM) based approach to perform search interface segmentation. Automatic processing of an interface is a must to access the invisible contents of deep Web. This entails automatic segmentation, i.e., the task of grouping related components of an interface together. While it is easy for a human to discern the logical(More)
Many problems in Information and Data Management require a semantic account of a database schema. At its best, such an account consists of formulas expressing the relationship (“mapping”) between the schema and a formal conceptual model or ontology (CM) of the domain. In this paper we describe the underlying principles, algorithms, and a prototype tool that(More)
BACKGROUND Epidemiological evidence supports a role for the insulin-like growth factors (IGFs) and their receptor, IGF-IR, in the induction and progression of various cancers. Estrogen receptor alpha (ERalpha), which plays a role in the etiology of ovarian cancer, both regulates and is influenced by the IGF family. PATIENTS AND METHODS We present a case(More)
There is a growing need to define a semantic mapping from a database schema to an ontology. Such a mapping is an integral part of the data integration systems that use an ontology as a unified global view. However, both ontologies and database schemas evolve over time in order to accommodate updated information needs. Once the ontology and the database(More)