Existing communication utilities, such as the ISO/OSI model and the associated automation pyramid, have limitations regarding the increased complexity of modern automation systems. The introduction of profiles for fieldbus systems, or field-area networks (FANs), was an important innovation. However, in the foreseeable future the number of FAN nodes in building automation systems is expected to increase drastically. And here the authors see an opportunity to revolutionize the operation of intelligent, autonomous systems based on FANs. The paper introduces a system based on bionic principles to process the information obtained from a large number of diverse sensors. By means of multilevel symbolization, the amount of information to be processed is substantially reduced. A symbolic processing model is introduced that enables the processing of real world information, creates a world representation, and evaluates scenarios that occur in this representation. Two applications involving human actions in a building automation environment are briefly discussed. It is argued that the use of internal symbolization leads to greater flexibility in the case of a large number of sensors, providing the ability to adapt to changing sensor inputs in an intelligent way.

The fast correlation attack described by Meier and Staffelbach [6] on certain classes of stream ciphers, based on linear feedback shift registers, requires that the number of taps of the characteristic polynomial must be small-typically less than 10. The attack can be extended to characteristic polynomials with an arbitrary number of taps if it is possible to compute low-weight polynomial multiples of the feedback polynomial. In this paper we present an algorithm for the efficient computation of low-weight parity checks. The algorithm, based on the theory of cyclic block error-correcting codes, applies the ideas underlying majorlty-logic decoding of maximal-length codes. A statistical analysis shows that it is not realistic to consider weight-3 parity checks, and hence it is necessary to compute weight-4 parity checks. The proposed algorithm has a worst-case computational complexity of O(22k/s), which is essentially independent of the number of taps of the characteristic polynomial, and is suitable for linear feedback shift registers of approximately 100 bits.

Abstract-This paper presents an in-depth analysis and evaluation of the security of UMTS. Four classes of attacks and threats are discussed in detail. Thereafter, the available security mechanism and services of UMTS are reviewed and evaluated. It is found that most of the potential attacks and threats can be thwarted by the available security services and mechanisms of UMTS.

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