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Research and Advances

Processing encrypted data

A severe problem in the processing of encrypted data is that very often, in order to perform arithmetic operations on the data, one has to convert the data back to its nonencrypted origin before performing the required operations. This paper addresses the issue of processing data that have been encrypted while the data are in an encrypted mode. It develops a new approach for encryption models that can facilitate the processing of such data. The advantages of this approach are reviewed, and a basic algorithm is developed to prove the feasibility of the approach.
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Research and Advances

A metamodel of information flow: a tool to support information systems theory

In this paper an axiomatic, fundamental metamodel of data flow is constructed. The components of the metamodel are the states along the flow of data: physical events, language (data), stored data, human data processing, and decision making. Transfers from one state to another are performed by functions: coding, keying, processing, perceptions, and human acting. The entire flow is evaluated by a value function. Each of the states and functions is rigorously described by means of definitions, axioms, and theorems. The main purpose of the metamodel is to provide a common framework for various models in MIS and consequently to remedy the "Tower of Babel" syndrome prevailing in this area. The way the metamodel can be used to develop other models in MIS is explained in the last part of the paper.
Research and Advances

The 1984 Olympic Message System: a test of behavioral principles of system design

There was more than athletic talent being pressed to peak performance at the 1984 Olympic Games in Los Angeles. Behind the scenes, a multilingual Olympic Message System ran round-the-clock keeping more than 10,000 athletes and officials in contact with families and friends, both far and near.
Research and Advances

Walsh-spectral test for GFSR pseudorandom numbers

By applying Weyl's criterion for k-distributivity to GFSR sequences, we derive a new theoretical test for investigating the statistical property of GFSR sequences. This test provides a very useful measure for examining the k-distribution, that is, the statistical independence of the k-tuple of successive terms of GFSR sequences. In the latter half of this paper, we describe an efficient procedure for performing this test and furnish experimental results obtained from applying it to several GFSR generators with prime period lengths.
Research and Advances

Laws of programming

A complete set of algebraic laws is given for Dijkstra's nondeterministic sequential programming language. Iteration and recursion are explained in terms of Scott's domain theory as fixed points of continuous functionals. A calculus analogous to weakest preconditions is suggested as an aid to deriving programs from their specifications.
Research and Advances

An experimental procedure for simulation response surface model identification

An experimental method for identifying an appropriate model for a simulation response surface is presented. This technique can be used for globally identifying those factors in a simulation that have a significant influence on the output. The experiments are run in the frequency domain. A simulation model is run with input factors that oscillate at different frequencies during a run. The functional form of a response surface model for the simulation is indicated by the frequency spectrum of the output process. The statistical significance of each term in a prospective response surface model can be measured. Conditions are given for which the frequency domain approach is equivalent to ranking terms in a response surface model by their correlation with the output. Frequency domain simulation experiments typically will require many fewer computer runs than conventional run-oriented simulation experiments.
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Research and Advances

Knowledge abstraction

One of the primary effects of software abstraction has been to further the notion of computer programs as objects rather than moving programming closer to the problem being solved. Knowledge abstraction, however, allows software to take a significant step toward the problem domain.

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