Volume 30 (2022): Edizione 2 (June 2022)

Smart building concepts are a relevant topic for the Ukrainian building sector. Although the current policy is mostly dedicated to the improvement of the current energy-saving situation in the building stock, the concept discussed could provide valuable inputs in the realization of the existing strategy. For an assessment of the expected positive impact of the implementation of smart indicators on building operation and renovation processes, as well as the predictions of scenarios of the range of the application of smart instruments, the research presented proposes a thorough analysis of the building stock in Ukraine and, in a real pilot case, the assessment of smart-readiness indicators (SRI) for a complex multi-family building. The case scenarios used, which are derived on the basis of SRI and a processed questionnaire among the habitants, are considered as the reference foundation for a practical application and disseminating the concept for similar cases.

To quantify the effect of a current on the height of a wave’s run-up and overtopping combined with an oblique wave approach, the “FlowDike” hydraulic research project was carried out. Tests were performed on two dike slopes of 1:3 and 1:6. Waves were generated across (perpendicular to) the physical model and also inclined in-plane to the stream axis. Oblique waves were generated both towards and along the flow’s direction. The effect of the current and of the wave direction on the height of the wave run-up and amount of the wave overtopping was expressed by means of a combined correction factor for the wave’s inclination and flow velocity. The results of the research confirmed that the flow velocity had only a small effect.

The application of alternative mathematical methods in creating cartographic projections is an interesting factor, which affects the optimization of distortions and their distribution in the projected territory. This article presents the methodology for the creation and comparison of conformal cartographic projections formed by alternative mathematical methods of minimizing the integral criterion for scale distortion in Slovakia. The creation of the variational projection is based on the Airy-Kavraiskii criterion of evaluating the projection on the displayed area by solving Laplace's equation. The second projection is created by solving Poisson's equation using Ritz's method. Our analysis showed that the variational projection of Slovakia achieves more satisfactory distortion values than the cartographic projection created using Ritz's method. The advantage of Ritz's method is that it is possible to choose a boundary condition for a predefined undistorted convex closed curve. In this paper, we have also derived specific members of the map equations for cartographic projection based on solving Poisson's equation by Ritz's method.

Groundwater modelling needs a large number of piezometer well data, which is unfortunately not always available as earlier registered data series are not always continuous. The reconstruction of data series with gaps was previously examined on a small riverside pilot area with the help of multiple regression, this method has now been tested at a 50-times larger environment. The results show that the reconstruction of the data series with this method works with average monthly groundwater levels and that applying multiple regression with the independent variables being one of the wells and the river optimizes the accuracy of the calculated data series, even if the relationships between the river and the wells are weak. The effect of the multiple regression on the accuracy is greater if the data series is sparser.

Coal ash is a geomaterial with a metastable structure. This type of geomaterial is significantly susceptible to liquefaction as a result of seismic loads. An investigation of ash that is susceptible to liquefaction due to a seismic load can use the CPT penetration test. This method of investigating liquefaction was developed based on numerous penetration tests of sandy or silty–sandy soils and was developed at the Workshop on the Evaluation of Soil Liquefaction Resistance, NCEER, Salk Lake City, Utah, USA, 1996. In the present article, the results of the CPT penetration test conducted at the Rosina ash tailings pond in Žilina in Slovakia, are analyzed using the NCEER methodology. The safety factor for ash liquefaction was expressed based on the penetration resistance values measured in the CPT tests using the ‘LiquefyPro’ software. The safety factor in the liquefaction of the ash sediment was expressed by changing the level of seeping water in the body of the tailings pond, the unit weight of coal ash, and the seismic acceleration.

The article deals with developing and testing a low-cost measuring system for simultaneous localisation and mapping (SLAM) in an indoor environment. The measuring system consists of three orthogonally-placed 2D lidars, a robotic platform with two wheel speed sensors, and an inertial measuring unit (IMU). The paper describes the data processing model used for both the estimation of the trajectory of SLAM and the creation of a 3D model of the environment based on the estimated trajectory of the SLAM. The main problem of SLAM usage is the accumulation of errors caused by the imperfect transformation of two scans into each other. The data processing developed includes an automatic evaluation and correction of the slope of the lidar. Furthermore, during the calculation of the trajectory, a repeatedly traversed area is identified (loop closure), which enables the optimisation of the trajectory determined. The system was tested in the indoor environment of the Faculty of Civil Engineering of the Slovak University of Technology in Bratislava.