Direct spread spectrum technology is traditionally used in radio communication systems with multiple access, for example, in CDMA standards, in global satellite navigation systems, in Wi-Fi network wireless protocols, etc. It ensures high security and reliability of information transfer. In addition, spread spectrum technology provides the transmitted signals with a noise-like appearance, thus hiding the semantic content of the messages. We researched this technology for other implementations. The purpose of our study was to investigate new technologies for hiding data in multimedia files. In particular, we investigated the direct spread spectrum in the context of the development of methods for hiding data in audio containers. We considered various spreading sequences (chip codes) and also explored their use for hiding information in audio files. We conducted experimental studies and estimated the bit error rate (BER) in the recovered data. The article also evaluates the distortion of an audio container by the peak signal-to-noise ratio (PSNR). The results of our research enable us to find out which method of forming chip codes gives a lower BER with equal PSNR. We provide recommendations on the formation of spreading sequences to reliably and safely hide informational messages in audio files.

The objective of the paper was to reveal the main techniques and means of ensuring the integrity of data and persistent stored database modules implemented in accordance with the recommendations of the Clark–Wilson model as a methodological basis for building a system that ensures integrity. The considered database was built according to the schema with the universal basis of relations. The mechanisms developed in the process of researching the problem of ensuring the integrity of the data and programs of such a database were based on the provisions of the relational database theory, the Row Level Security technology, the potential of the modern blockchain model, and the capabilities of the database management system on the platform of which databases with the universal basis of relations are implemented. The implementation of the proposed techniques and means, controlling the integrity of the database of stored elements, prevents their unauthorized modification by authorized subjects and hinders the introduction of changes by unauthorized subjects. As a result, the stored data and programs remain correct, unaltered, undistorted, and preserved. This means that databases built based on a schema with the universal basis of relations and supported by such mechanisms are protected in terms of integrity.

This paper presents a data mining technique for qualitative analysis of Hodgkin-Huxley model of cell excitability. Such problem cannot be solved analytically. Therefore we apply Monte-Carlo techniques for the generation of model parameters, and use data mining algorithm for classification of learning tuples obtained. As a result we attain a decision tree capable of classifying the excitability depending on the relationship between initial conditions and between rate constants. Details of software development and issues of computational complexity are presented. The software includes the package of Java-classes. An example for classification of excitability of three types is presented.

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