International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Four of most of popular Bulgarian application were selected, namely “100 Places Bulgaria“, “I Love Bulgaria”, “Опознай.bg“ and ”The one hundred national tourist sites of Bulgaria”, and compare them. Data collection was performed through an electronic questionnaire, which was based on Google Forms. The article presents the need for a solid theoretical foundation for understanding the complexity and multi-layeredness of user experience (UX) and user interface (UI) in the context of digital transformation.

The article deals with the steganography system which hides text inside images without losing data in components of RGB model The secret message is hidden in the cover image using Least Significant Bit (LSB) algorithm. The comparative results for the proposed algorithm are very promising for blue components of image. To evaluate steganography system properties are used the measures like Signalto- Noise Ratio (SNR), Peak Signal-to-Noise Ratio (PRSN), Mean Squared Error (MSE) and Structural Similarity Index for measuring (SSIM). The aim of the study is to determine whether there is a change in the qualitative characteristics of the stego image, when it is hidden the same information, but in a different color channel, to determine which color channel shows the most invisibility to others and is it advisable to be used in the transmission of confidential information.

In this article some of main characteristics of caterpillar vehicle’s straight motion are depict. An analytical method for working out formulas for maximum speed, acceleration and time and route for acceleration is suggested.