Programming of Reliable Distributed Computations in Nondeterministic Computer Environments on the Basis of Calculus of Treelike Structures

2009 ◽  
Author(s):  
Zatuliveter, Yurii
Keyword(s):  
Distributed Computations ◽  
Computer Environments

scholarly journals On the Fly Testing of Regular Patterns in Distributed Computations

1994 ◽  
Author(s):  
Eddy Fromentin ◽  
Michel Raynal ◽  
Vijay Garg ◽  
Alex Tomlinson
Keyword(s):  
Distributed Computations ◽  
Regular Patterns

Effects of Computer and Noncomputer Environments on Students' Conceptualizations of Geometric Motions

1994 ◽  
Vol 11 (2) ◽  
pp. 121-140 ◽  
Author(s):  
Kay Johnson-Gentile ◽  
Douglas H. Clements ◽  
Michael T. Battista
Keyword(s):  
Control Group ◽  
Treatment Groups ◽  
Geometric Thinking ◽  
Paper And Pencil ◽  
Computer Environments

This study investigated the effects of computer and noncomputer environments on learning of geometric motions. Two treatment groups, one of which used specially designed Logo computer environments, and one of which used manipulatives and paper and pencil, received eight lessons on geometric motions. Interviews revealed that both treatment groups, especially the Logo group, performed at a higher level of geometric thinking than did a control group. Both treatment groups outperformed the control group on immediate and delayed posttests; though the two treatment groups did not significantly differ on the immediate posttest, the Logo group outperformed the nonLogo group on the delayed posttest. Thus, there was support for the effectiveness of the curriculum and for the notion that the Logo-based version enhanced the construction of higher-level conceptualizations of motion geometry.

scholarly journals Even Simple Processes of π-calculus are Hard for Analysis

2018 ◽  
Vol 25 (6) ◽  
pp. 589-606
Author(s):  
Marat M. Abbas ◽  
Vladimir A. Zakharov
Keyword(s):  
Information Security ◽  
Mathematical Models ◽  
Cryptographic Protocols ◽  
Bounded Number ◽  
Distributed Computations ◽  
Security Properties ◽  
Mobile Processes ◽  
Π Calculus ◽  
Np Complete ◽  
Turing Complete

Mathematical models of distributed computations, based on the calculus of mobile processes (π-calculus) are widely used for checking the information security properties of cryptographic protocols. Since π-calculus is Turing-complete, this problem is undecidable in general case. Therefore, the study is carried out only for some special classes of π-calculus processes with restricted computational capabilities, for example, for non-recursive processes, in which all runs have a bounded length, for processes with a bounded number of parallel components, etc. However, even in these cases, the proposed checking procedures are time consuming. We assume that this is due to the very nature of the π -calculus processes. The goal of this paper is to show that even for the weakest model of passive adversary and for relatively simple protocols that use only the basic π-calculus operations, the task of checking the information security properties of these protocols is co-NP-complete.

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