Evaluation of Functional Data Models for Database Design and Use

The problems of design, operation, and maintenance of databases using the three most popular database management systems (Hierarchical, CQDASYL/DBTG, and Relational) are well known. Users wishing to use these systems have to make conscious and often complex mappings between the real-world structures and the data structuring options (data models) provided by these systems. In addition, much of the semantics associated with the data either does not get expressed at all or gets embedded procedurally in application programs in an ad-hoc way. In recent years, a large number of data models (called semantic data models) have been proposed with the aim of simplifying database design and use. However, the lack of usable implementations of these proposals has so far inhibited the widespread use of these concepts. The present work reports on an effort to evaluate and extend one such semantic model by means of an implementation. It is based on the functional data model proposed earlier by Shipman[SHIP81). We call this 'Extended Functional Data Model' (EFDM). EFDM, like Shipman's proposals, is a marriage of three of the advanced modelling concepts found in both database and artificial intelligence research: the concept of entity to represent an object in the real world, the concept of type hierarchy among entity types, and the concept of derived data for modelling procedural knowledge. The functional notation of the model lends itself to high level data manipulation languages. The data selection in these languages is expressed simply as function application. Further, the functional approach makes it possible to incorporate general purpose computation facilities in the data languages without having to embed them in procedural languages. In addition to providing the usual database facilities, the implementation also provides a mechanism to specify multiple user views of the database

Decision Support Systems: Issues and Challenges; Proceedings of an International Task Force Meeting, June 23-25, 1980

This book reports on a three-day meeting on Decision Support Systems held at IIASA. IIASA's interest in sponsoring the meeting was spurred by several factors. First, the term DSS clearly is used in a wide range of contexts; we hoped to develop a deeper understanding of the term and the new field to which it refers. Second, we felt that ongoing work in the DSS field would be enhanced by interaction between professionals who had been working on such systems and people from fields that function as "resource disciplines" for DSS. Finally we wished to bring professionals from several nations together, from the east as well as the west, to share experiences and to assess the viability of the DSS concept in different cultures. The broad objectives set for this meeting were realized in a number of ways. Virtually all the participants testified that they had gained a deeper understanding of DSS, the role it can play in asssisting managers in organizations, and the need for further development in key areas

Economic data bank management in a developing nation

This dissertation describes the results of a research project which was undertaken at Loughborough University of Technology. The basic objectives of the research project were: (1) to investigate the management elements required for organising the development of an Economic Data Bank (EDB), with particular emphasis on the requirements of a developing nation; (2) to investigate the sociological, political and technical implications associated with organising the development of an EDB in a developing nation. A theoretical framework was established for this study. This was dene after an extensive search and review of literature was performed in the areas of data and data base management systems, management information systems, and computer technology in general. [Continues.

IMPLOSION DYNAMICS, RADIATION CHARACTERISTICS, AND SPECTROSCOPIC MEASUREMENTS OF WIRE-ARRAY Z-PINCHES ON THE CORNELL BEAM RESEARCH ACCELERATOR (COBRA)

This dissertation presents the results of two experimental studies of wire-array z-pinches on the 1-MA, 100-ns rise-time Cornell Beam Research Accelerator (COBRA). In the first study, results are presented which characterize the implosion dynamics and radiation output of wire array z-pinches on COBRA. Here the load geometries investigated include 10- and 20-mm tall cylindrical arrays ranging from 4 to 16 mm in diameter, and consisting of 8, 16, or 32 wires of either tungsten, aluminum, or Invar (64\% iron, 36\% nickel). Diagnostics fielded include an optical streak camera, a time-gated extreme-ultraviolet framing camera, a laser shadowgraph system, time-integrated pinhole cameras, an x-ray wide-band focusing spectrograph with spatial resolution, an x-ray streak camera, a load voltage monitor, a Faraday cup, a bolometer, silicon diodes, and diamond photoconducting detectors. The data produced by the entire suite of diagnostics are analyzed and presented to provide a detailed picture of the overall implosion process and resulting radiation output on COBRA. The highest x-ray peak powers (300--500 GW) and total energy yields (6--10 kJ) were obtained using 4-mm-diameter arrays that stagnated before peak current. Additional findings include a decrease in soft x-ray radiation prior to stagnation as the initial wire spacing was changed from 1.6 mm to 785 $\mu$m, and a timing correlation between the onset of energetic electrons, hard x-ray generation, and the arrival of trailing current on axis---a correlation that is likely due to the formation of micro-pinches. The details of these and other findings are presented and discussed. In the second study, a new diagnostic setup was developed to record the visible-light spectra emitted from aluminum wire-array plasmas as a continuous function of time. To accomplish this, a half-meter Czerny-Turner spectrometer was used in conjunction with the existing visible light streak camera system. The emitted spectra was seen to consist solely of continuum radiation. This continuum data is now being used to determine electron density. To determine electron density from the continuum data, an absolute calibration of the detection system was required. The details of these experiments, and the absolute calibration technique are presented.This research was partially supported by Sandia National Laboratories Contract No. AO258 and by the Stewardship Science Academic Alliances program of the National Nuclear Security Administration under the Department of Energy Cooperative Agreement No. DE-FC03-02NA00057