Over the past few years there has been an increase in the use of data base systems and computer graphics in scientific and engineering applications. While considerable work has been done on both graphics and data base support very little has been done on the interaction between the two. In this paper we discuss a graphical data base system that we have used in a number of applications. We descr...

A particularly simple Markov chain model for a reference string is described. The model, which is only slightly more complicated than the independent reference model, generates strings that have a locality property and that have a specified probability distribution of references over pages. Expressions are obtained for expected working-set size and expected working-set miss ratio. The of change...

The problem of data privacy is to verify that confidential information stored in an information system is not provided to unauthorized users and, therefore, personal and other sensitive data remain private. One way to guarantee this is to distort a knowledge base such that it does not reveal sensitive information. In the present paper we will give a definition of the problem of knowledge base d...

With the quick development of the semantic web technology, RDF data explosion has become a challenging problem. Since RDF data are always from different resources, which may have overlap with each other, they could have duplicates. These duplicates may cause ambiguity and even error in reasoning. However, attentions are seldom paid to this problem. In this paper, we study the problem and give a...

We present a model for processing English requests for information from a relational data base. The model has as its main steps (a) locating semantie constituents of a request; (b) matching these constituents against larger templates called concept case frames; (c) filling in the concept case frame using information from the user's request, from the dialogue context and from the user's response...

In this paper we briefly present the design of a distributed relational data base system. Then, we discuss experimental observations of the performance of that system executing both short and long commands. Conclusions are also drawn concerning metrics that distributed query processing heuristics should attempt to minimize. Lastly, we comment on architectures which appear viable for distributed...

Data base management evolved during the sixties and seventies. The evolution period was protracted. Many driving forces impacted the evolution and it is the aim of this paper to analyze these driving forces (some technical and some political) and to discuss the impact of each. The driving forces are identified as follows: higher level languages, generalization of software, non-procedural approa...

Query optimization is a difficult task in a distributed client/server environment as data location becomes a major factor. In order to optimize queries accurately, sufficient information must be available to determine which data access techniques are most effective. Optimization algorithms have an important impact on the performance of distributed query processing.. Various algorithms are used ...

I n a well-structured Lexica] Data B a s e , a number of relations among lexica] entries can he interactively evidenced. The present article examines hyponymy, as an example of paradigmatic relation, and "restriction" relation, as a syntagmatic relation. The theoretical results of their implementation are illustrated.