Nikolaos Doukas

Optimised information system reliability techniques for knowledge society acceptance

Two important obstacles averting the widespread adoption of knowledge society and e-government technologies in communities are distrust in their reliability and fear of the costs to be incurred. In order to overcome these obstacles, algorithmic advances are required that improve reliability of information systems without increasing their cost. In this paper a new approach to increase the reliability and effectiveness of transient error detection using checksum calculations is proposed, that is based on the optimisation of coding with special differential Boolean transformations. Two methods for obtaining such transformations are developed and examples of coding for checksum functions are given. The new methods are equivalent in terms of computational cost as classical checksum approaches.

Fast subscriber identification based on the zero knowledge principle for multimedia content distribution

In this article, an innovative method is proposed for the realisation of zero knowledge subscriber identification schemes that is suitable for multimedia content distribution applications. The fundamental principle underlying the proposed method is the concept of using one-way Boolean functions as transformations for the zero knowledge identification. This enables the increase of the speed of completion of the identification process by two to three orders of magnitude, compared to the corresponding speed when using modular arithmetic with large numbers. A method for the establishment of one way Boolean functions for zero knowledge identification has been developed. Two examples for the application of the proposed method are presented.

Effective method to restore data in distributed data storage systems

In this work, a method for backup and restoring data is proposed. The data is stored on different remote disks (storage nodes) and temporary or permanent loss of access to any q of them appears. The high efficiency of the proposed method is achieved by using a theoretically proved minimum number of backup storage nodes, which is equal to the number of the disks to which access has been lost. The theoretical justification with a methodology of backup codes and their use for data recovery, which is illustrated by examples, is presented. The theoretical and experimental effectiveness evaluation of the proposed method is demonstrated as well. The proposed method is aimed to ensure a high level of survivability of system of distributed data storage for military applications.

Current trends in small vocabulary speech recognition for equipment control

Speech recognition systems allow human – machine communication to acquire an intuitive nature that approaches the simplicity of inter – human communication. Small vocabulary speech recognition is a subset of the overall speech recognition problem, where only a small number of words need to be recognized. Speaker independent small vocabulary recognition can find significant applications in field equipment used by military personnel. Such equipment may typically be controlled by a small number of commands that need to be given quickly and accurately, under conditions where delicate manual operations are difficult to achieve. This type of application could hence significantly benefit by the use of robust voice operated control components, as they would facilitate the interaction with their users and render it much more reliable in times of crisis. This paper presents current challenges involved in attaining efficient and robust small vocabulary speech recognition. These challenges concern feature selection, ...

Erasure Code for Efficient Error Correction in Block Data Transmission

This paper proposes an innovative technique for correcting transmission burst errors in data transmitted over amplitude modulated channels suffering from strong electromagnetic interference, such as encountered in military situations. Efficiency is achieved by separating the error detection from the correction process and using different codes for each case. The proposed technique is based on simple mathematical operations and is suitable for implementation in FPGA devices. It is shown to be more efficient than existing ones, according to criteria that are relevant to current applications.