Virtual integration of temporal and conflicting information

This paper is presenting a way of integrating conflicting temporal information from multiple information providers considering a property-based resolution. The properties considered in this paper are the time and uncertainty because of conflicting information providers. The property based resolution requires a flexible query mechanism, where answers are considered as bounds, taking into account the tendency of things to occur and also the might happen ability of things. Finally some attention is paid to a database environment with non-static members

Probabilistic Temporal Databases, I: Algebra

Dyreson and Snodgrass have drawn attention to the fact that in many temporal database applications, there is often uncertainty present about the start time of events, the end time of events, the duration of events, etc. When the granularity of time is small (e.g. milliseconds), a statement such as "Packet p was shipped sometime during the first 5 days of January, 1998" leads to a massive amount of uncertainty (5 times 24 times 60 times 60 times 1000) possibilities. As noted by Zaniolo et. al., past attempts to deal with uncertainty in databases have been restricted to relatively small amounts of uncertainty in attributes. Dyreson and Snodgrass have taken an important first step towards solving this problem. In this paper, we first introduce the syntax of Temporal-Probabilistic (TP) relations and then show how they can be converted to an explicit, significantly more space-consuming form called Annotated Relations. We then present a {\em Theoretical Annotated Temporal Algebra} (TATA). Being explicit, TATA is convenient for specifying how the algebraic operations should behave, but is impractical to use because annotated relations are overwhelmingly large. Next, we present a Temporal Probabilistic Algebra (TPA). We show that our definition of the TP-Algebra provides a correct implementation of TATA despite the fact that it operates on implicit, succinct TP-relations instead of the overwhelmingly large annotated relations. Finally, we report on timings for an implementation of the TP-Algebra built on top of ODBC. (Also cross-referenced as UMIACS-TR-99-09

Feasibility of using citations as document summaries

The purpose of this research is to establish whether it is feasible to use citations as document summaries. People are good at creating and selecting summaries and are generally the standard for evaluating computer generated summaries. Citations can be characterized as concept symbols or short summaries of the document they are citing. Similarity metrics have been used in retrieval and text summarization to determine how alike two documents are. Similarity metrics have never been compared to what human subjects think are similar between two documents. If similarity metrics reflect human judgment, then we can mechanize the selection of citations that act as short summaries of the document they are citing. The research approach was to gather rater data comparing document abstracts to citations about the same document and then to statistically compare those results to several document metrics; frequency count, similarity metric, citation location and type of citation. There were two groups of raters, subject experts and non-experts. Both groups of raters were asked to evaluate seven parameters between abstract and citations: purpose, subject matter, methods, conclusions, findings, implications, readability, andunderstandability. The rater was to identify how strongly the citation represented the content of the abstract, on a five point likert scale. Document metrics were collected for frequency count, cosine, and similarity metric between abstracts and associated citations. In addition, data was collected on the location of the citations and the type of citation. Location was identified and dummy coded for introduction, method, discussion, review of the literature and conclusion. Citations were categorized and dummy coded for whether they refuted, noted, supported, reviewed, or applied information about the cited document. The results show there is a relationship between some similarity metrics and human judgment of similarity.Ph.D., Information Studies -- Drexel University, 200

Database Models for Infinite and Indefinite Temporal Information

Representation and querying of temporal information can benefit from the integration of techniques from constraint databases, database models for indefinite information and reasoning about temporal constraints. With this perspective in mind, we present a hierarchy of temporal data models: temporal relations, generalized temporal relations and temporal tables. We study the semantics of these models and develop algebraic and calculus query languages for them. The proposed models can be useful to several novel applications include planning, scheduling, project management, medical information systems, geographical information systems and natural language processing systems. 1 Introduction Research in temporal databases has mostly concentrated on temporal models with definite temporal information (e.g., "the salary of Jones was $20,000 from January 1989 to April 1989") [62, 58]. There are few exceptions to this general rule. [11] was the first paper to investigate infinite periodic data (e..