This paper introduces security assessment methodology for isolated single-workstation multilayer systems processing sensitive or classified data according with a corresponding security model for such system. The document provides a high-level tool for systematizing certain-class-systems security models development. The models based on the introduced methodology cover data confidentiality and availability attributes protection on a sufficient level.

In this study, Al 2024-T3 alloy plates were joined by using friction stir welding. Welding was performed at a rotational speed of 930, 1450, 2280 rpm and a welding feed rate of 180 mm min ⁻¹. The welded samples were analyzed at the microstructural level. Moreover, both bending fatigue tests and tensile tests were performed on samples. At the end of the microstructural examination of the samples welded at the rotational speed of 930 rpm and the welding feed rate of 180 mm min ⁻¹, the formation of tunnel defects was observed. The highest fatigue life was obtained at 2280 rpm and 180 mm min ⁻¹. The lowest fatigue life was obtained at 930 rpm and 180 mm min ⁻¹. The highest ultimate tensile stress was obtained at 2280 rpm/180 mm min ^–1 sample, which shows about a 12% reduction relative to the base material. The lowest ultimate tensile stress was obtained at 930 rpm/180 mm min ^–1 sample. The ultimate tensile stress value of the 930 rpm/180 mm min ^–1 sample decreased by approximately 25%.

Day-boundary discontinuity (DBD) is an effect present in precise GNSS satellite orbit and clock products originating from the method used for orbit and clock determination. The non-Gaussian measurement noise and data processing in 24 h batches are responsible for DBDs. In the case of the clock product, DBD is a time jump in the boundary epochs of two adjacent batches of processed data and its magnitude might reach a couple of ns. This article presents the four GNSS (Global Navigation Satellite System) systems DBD analysis in terms of change over an 8 year period. For each of 118 satellites available in this period, the yearly value of DBD was subject to analysis including standard deviation and frequency of outliers. Results show that the smallest DBDs appear in the GPS system, the biggest – for the BeiDou space segment. Moreover, the phenomenon of changes in DBDs over time is clearly seen at the beginning of the analysed period when the magnitude and number of the DBDs were larger than for current, newest clock products

It is possible to enhance acoustic isolation of the device from the environment by appropriately controlling vibration of a device casing. Sound insulation efficiency of this technique for a rigid casing was confirmed by the authors in previous publications. In this paper, a light-weight casing is investigated, where vibrational couplings between walls are much greater due to lack of a rigid frame. A laboratory setup is described in details. The influence of the cross-paths on successful global noise reduction is considered. Multiple vibration actuators are installed on each of the casing walls. An adaptive control strategy based on the Least Mean Square (LMS) algorithm is used to update control filter parameters. Obtained results are reported, discussed, and conclusions for future research are drawn.