Ralph D. Semmel

Learn More
Significant effort is expended in developing a high-level conceptual schema for a relational database. However, criticalknowledge is often discarded when the conceptual schema is mapped to aset of relation schemas. As a result, designers and users must employsparser logical-level knowledge to access data. Unfortunately, naiveusers do not possess the(More)
user interaction from the logical level to the conceptual level. Furthermore, with appropriate meta-level abstractions, the need for conceptuallevel knowledge can be significantly reduced. In this article, we focus on how queries can be automatically generated from high-level requests over a set of fused databases. In the next section, a system known as(More)
he U.S. Army, like many large organizations, relies upon heterogeneous and distributed information systems for managing massive quantities of data. Formulating queries within these systems has been difficult because of the underlying structural complexity of the associated databases. Formulating queries across these systems has been impossible because of(More)
Expert systems are providing a means of solving complex problems that previously defied automation efforts. This paper explains what an expert system is and how one operates. Following a brief description of expert systems, the nature of computer problem-solving and the role of knowledge in that activity are discussed. A typical expert system architecture(More)