In this paper we present a simple database definition language: that of categories and functors. A database schema is a category and a state is a set-valued functor. We show that morphisms of schemas induce three “data migration functors” that translate states from one schema to the other in canonical ways. Database states form a topos of which the classical “relational algebra” is a fragment. ...

the present study investigates the performance and relative accuracy of four lattice-hole theory based equations of state in modeling and correlating the liquid density of pure refrigerants. following the gathering of a database of 5740 experimental liquid density datapoints of 36 pure refrigerants belonging to five different categories including cfcs, hcfcs, pfcs, hfcs and hfes, ranging from 6...

this project aims at collecting and cataloging the information pertaining to the research projects and documents concerning water resource. the data collected along with abstracts were entered into worksheets in compliance with us- marc bibliographic format. they were fed into the computer following the necessary validation process. so far more than 5000 documents (proceedings, research report,...

In database theory, the term database transformation was used to refer to a unifying treatment for computable queries and updates. Recently, it was shown that non-deterministic database transformations can be captured exactly by a variant of ASMs, the so-called Database Abstract State Machines (DB-ASMs). In this article we present a logic for DBASMs, extending the logic of Nanchen and Stärk for...

Currently, many companies and institutions use centralized or distributed databases to store massive amounts of data. However, the untrusted third-party auditors can result in security issues because these may be malicious tamper with delete user This poses a significant challenge for ensuring reliability data verification results. Although introducing auditor help address this issue, it also u...