- Email: [email protected]
Language description and implementation concepts of LITFAS (Language for implications from textual files and atomic sentences)
173
Decision Support Systems Reports and Theses: Abstracts Matts Aldsen, Anders Bjoernerstedt, Stefan Britts, Christer Hulten and Lars Soededund: Making Type Changes Transparent, SYSLAB-S, University of Stockholm, (February 1984). Systems for processing structured data are generally poor at coping with changes in the structure of data objects (type changes). This becomes a problem when the objects are stored in a database for access by many processes over long periods of time. If the system is distributed and the processes loosely coordinated, as will often be the case in office information systems, reorganization of the database may be impossible. The focus of the paper is on the introduction and elaboration of the form type version concept, essentially a particular kind of oiew, in database terminology. This concept~ as an alternative to reorganization of the object database, is shown to make the design tools and languages in an object management system more capable at handling type changes. One goal is to make type changes transparent as far as possible. The paper elaborates on principally different ways to achieve this goal. Authors' Abstract
Earl A. Barnes and Alan J. Hoffman: Partitioning, Spectra anti Linear Programming, Rep. RC 9511, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, U.S.A., (August 1982). We obtain lower bounds on the value of the objective in a graph partitioning problem in terms of spectral information about the graph. Our approach introduces a class of generalized transportation problems which can be solved in greedy fashion using the Monge sequence idea. Authors~ Abstract
North-Holland Decision Support Systemsl (1985) 173-184
E. Bettsch: Language Description and Implementation Concepts of LITFAS (Language for Implications from Textual Files and Atomic Sentences), Informatik Bericht, FernUniversitM Hagen, (April 1984). We define a simple, high-level language that combines essential features of logic programming with a natural file query formalism. The internal sequence of deduction steps is entirely hidden from the user. A rough outline of the implementation is also presented. It turns out that the file access mechanism demands a separate kind of backtracking. Numerous examples are given to demonstrate the expressive power of the language. Authors' Abstract
Kadaba Bharath-Kumar and Parviz Kermani: Performance Evaluation Tool (PET): An Analysis Tool for Computer Communication Networks, IBM T.J. Watson Research Center, Yorktown Heights, (Dec. 1982). The Performance Evaluation Tool (PET) is a package to aid the designers of architecture and protocols of Computer Networks. It is specially targeted, but not limited, to IBM's Systems Network Architecture (SNA) networks. The tool allows its users the capability to easily construct simulation models of networks and conduct traffic related performance studies. PET is based on the Research Quenching Package (RESQ)-Version 2, which is a package for constructing and analyzing extended queueing network models. The two key features of PET are ease of use and flexibility. The user specifies the network configuration with the aid of an interactive "networking language". This includes a description of the type of representation he/she desires for the various protocols at different layers of the architecture. Based on these specifications, PET builds a RESQ simulation model for the network by piecing to-
0167-9236/85/$3.30 © 1985, Elsevier Science Publishers B.V. (North-Holland)
Decision Support Systems Reports and Theses: Abstracts Matts Aldsen, Anders Bjoernerstedt, Stefan Britts, Christer Hulten and Lars Soededund: Making Type Changes Transparent, SYSLAB-S, University of Stockholm, (February 1984). Systems for processing structured data are generally poor at coping with changes in the structure of data objects (type changes). This becomes a problem when the objects are stored in a database for access by many processes over long periods of time. If the system is distributed and the processes loosely coordinated, as will often be the case in office information systems, reorganization of the database may be impossible. The focus of the paper is on the introduction and elaboration of the form type version concept, essentially a particular kind of oiew, in database terminology. This concept~ as an alternative to reorganization of the object database, is shown to make the design tools and languages in an object management system more capable at handling type changes. One goal is to make type changes transparent as far as possible. The paper elaborates on principally different ways to achieve this goal. Authors' Abstract
Earl A. Barnes and Alan J. Hoffman: Partitioning, Spectra anti Linear Programming, Rep. RC 9511, IBM T.J. Watson Research Center, Yorktown Heights, New York 10598, U.S.A., (August 1982). We obtain lower bounds on the value of the objective in a graph partitioning problem in terms of spectral information about the graph. Our approach introduces a class of generalized transportation problems which can be solved in greedy fashion using the Monge sequence idea. Authors~ Abstract
North-Holland Decision Support Systemsl (1985) 173-184
E. Bettsch: Language Description and Implementation Concepts of LITFAS (Language for Implications from Textual Files and Atomic Sentences), Informatik Bericht, FernUniversitM Hagen, (April 1984). We define a simple, high-level language that combines essential features of logic programming with a natural file query formalism. The internal sequence of deduction steps is entirely hidden from the user. A rough outline of the implementation is also presented. It turns out that the file access mechanism demands a separate kind of backtracking. Numerous examples are given to demonstrate the expressive power of the language. Authors' Abstract
Kadaba Bharath-Kumar and Parviz Kermani: Performance Evaluation Tool (PET): An Analysis Tool for Computer Communication Networks, IBM T.J. Watson Research Center, Yorktown Heights, (Dec. 1982). The Performance Evaluation Tool (PET) is a package to aid the designers of architecture and protocols of Computer Networks. It is specially targeted, but not limited, to IBM's Systems Network Architecture (SNA) networks. The tool allows its users the capability to easily construct simulation models of networks and conduct traffic related performance studies. PET is based on the Research Quenching Package (RESQ)-Version 2, which is a package for constructing and analyzing extended queueing network models. The two key features of PET are ease of use and flexibility. The user specifies the network configuration with the aid of an interactive "networking language". This includes a description of the type of representation he/she desires for the various protocols at different layers of the architecture. Based on these specifications, PET builds a RESQ simulation model for the network by piecing to-
0167-9236/85/$3.30 © 1985, Elsevier Science Publishers B.V. (North-Holland)