Scientific Journals and Yearbooks Published at SAS

Article List

Computing and Informatics

Volume 22, 2003, No. 5
Content:

GROSEK, O. - SISKA, J.
Semigroup of Matrices over GF{2^s} and Its Relation to AES.
In Computing and Informatics. Vol. 22, no. 5 (2003), p. 417-426.
ZHOU, H. - LIN, Z. - CAO, W.
High-Level Technology Mapping for Memories.
In Computing and Informatics. Vol. 22, no. 5 (2003), p. 427-438.
KOLLAR, J.
Unified Approach to Environments in a Process Functional Language.
In Computing and Informatics. Vol. 22, no. 5 (2003), p. 439-456.
MARCEK, D.
Determination of fuzzy relations for economic fuzzy time series models by neural networks.
In Computing and Informatics. Vol. 22, no. 5 (2003), p. 457-471.
CHANDRA SAXENA, P. - JEET ARORA, I.
Continuous Access of Broadcast Data Using Artificial Pointers Under a Wireless Mobile Computing.
In Computing and Informatics. Vol. 22, no. 5 (2003), p. 473-510.

	Semigroup of Matrices over GF{2^s} and Its Relation to AES O. GROSEK, J. SISKA AES, MixColumn operation, Euler-Fermat theorem We introduce to readers a new matrix C for MixColumn operation for AES algorithm for discussion. This matrix has significantly larger multiplicative order, ord(C) = 340, than the used one which is 4 only. This makes so called XSL attack less effective. It is possible to find such a matrix due to our new Euler-Fermat-like theorem and its corollaries for regular circulant matrices over GF(p^s). Computing and Informatics. Volume 22, 2003, No. 5: 417-426.
	High-Level Technology Mapping for Memories HAIFENG ZHOU, ZHENGHUI LIN, WEI CAO Circuit CAD, digirtal circuit design, high-level synthesis, technology mapping In this paper, we consider memory-mapping problems in High-Level Synthesis. We focus on the port mapping, bit-width mapping and word mapping, respectively. A 0-1 Integer Linear Programming (ILP) technique is used to solve the mapping problems, which synthesizes the source memory using one or more memory modules from a target memory library at a higher level. This method can not only perform bit-width mapping and word mapping, but it can also perform port mapping at the same time. Experimental results indicate that ILP approach is an effective method for memory reuse in high-level synthesis. Computing and Informatics. Volume 22, 2003, No. 5: 427-438.
	Unified Approach to Environments in a Process Functional Language JAN KOLLAR Programming paradigms, implementation principles, explicit and implicit environment, environmental application, control driven dataflow, referential transparency, side effects A process functional paradigm is based on applications of processes and functions instead of assignments. The imperative computation and the functional evaluation are clearly separated in a well-balanced manner, providing the strong feedback about the implementation to a user. In this paper we present the unified approach to explicit and implicit environments in PFL -- an experimental process functional language, as a uniform basis for approved implementation extensible by additional specification. PFL environmental concept is the generalized implementation substance, which can be found in many programming languages exploiting the large variety of programming paradigms. Environment variables do not occur in expressions, being still visible to a programmer either in PFL textual form or in an equivalent form of control driven data flow graphs. The approach is promising for reasoning about Computing and Informatics. Volume 22, 2003, No. 5: 439-456.
	Determination of fuzzy relations for economic fuzzy time series models by neural networks DUSAN MARCEK Fuzzy time series models, fuzzy bank rules, product-space clustering, fuzzy controllers, neural networks Based on the works /11, 22, 27/ a fuzzy time series model is proposed and applied to predict chaotic financial process. Thwe general methodological framework of classical and fuzzy modelling of economic time series is considered. A complete fuzzy time series modellling approach is proposed which includes: determining and developing of fuzzy time series models, developing and calculating of fuzzy relations among the observations, calculating and interpreting the outputs. To generate fuzzy rules from data, the neural network with SCL-based product-space clustering is used. Computing and Informatics. Volume 22, 2003, No. 5: 457-471.
	Continuous Access of Broadcast Data Using Artificial Pointers Under a Wireless Mobile Computing PREM CHANDRA SAXENA, INDER JEET ARORA Data broadcasting, energy conservation, fault tolerance, mobile computing, version number In a ubiquitous information environment, massive number of users carrying their portable computers can retrieve information anywhere and anytime using wireless mobile computing technologies. Wireless data broadcasting as a way of disseminating information to the large number of clients, has an inherent advantage by providing all types of users global access to information. An adaptive access method, which tolerates the access failure, has been proposed in an error-prone mobile environment. However the influence of version bits to deal with the updates of the broadcast data has not been exploited for the broadcast with modified but the same size and structure update. The basic idea is to distinguish the type of update that does not influence the change in the size and structure of the broadcast has been introduced. To deal with the types of updates, we classified the users in mobile computing environment into the users in system and the new users. In the proposed continuous algorithms, the user in systems record the previous result and use it efficiently to access the desired records with less number of probes in the broadcast, which is updated by a stream of same size and structure bits. In the performance analysis, the experimental results show that the proposed modified progression method has the best performance, as it requires the minimum cost to access the broadcast data. Computing and Informatics. Volume 22, 2003, No. 5: 473-510.