Procter & Gamble (United Kingdom)
GraFar - Repository of the Faculty of Civil EngineeringNot a member yet
3934 research outputs found
Sort by
A note on matrices involving the Chebyshev polynomials
Get PDFIn this talk, we establish a connection between some classical topics in applied mathematics - circulant matrices and the Chebyshev polynomials. First, we define circulant matrices whose entries are the Chebyshev polynomials of the first or second kind and examine their basic properties. Then we determine the bounds of the norms of such matrices. It turns out that the obtained results can be seen as the unification and generalization of many previously obtained results on circulant matrices involving the generalized Horadam numbers. We point out one direction of applications, but it is clear that there are many possibilities. With appropriate modifications, these results can be applied in different areas, such as - statistics, data approximation, interpolation, engineering, economics, signal and image processing, numerical analysis, physics and error correcting code theory, to name but a few
Forecasting River Water Levels Influenced by Hydropower Plant Daily Operations using Artificial Neural Networks
Get PDFMultipurpose water systems are used to deal with multiple objectives related to the usage of water for daily human activities. These activities are often conflicted which creates a challenging water management task. To provide reliable water resources management decision support tools for successful forecasting of hydraulic data (river flows and water levels) are essential. This research presents an approach for forecasting river water levels influenced by hydropower plant operations using artificial neural networks. This approach estimates hourly water level fluctuations at the control location using the water levels and hydropower plant discharge data as input. This tool can be used for fast assessment of different hydropower plant operation plans and help in choosing the optimal one. This water level forecasting procedure is applied and tested on the Iron Gate water system, placed on the Danube River, to deal with multiple objectives in water system management (hydropower production, flood protection, and inland navigation) and shows promising results
Agricultural Land Use Changes as a Driving Force of Soil Erosion in the Velika Morava River Basin, Serbia
Get PDFThe erosion potential model was applied to estimate the soil erosion status of rural settlements during the years 1971 and 2011. We used univariate and bivariate local Moran’s I indices to detect and visualize the spatial clustering of settlements with respect to changes in erosion intensity and agricultural land use, as well as their mutual spatial correlation. The study area was differentiated into four statistically significant clusters using the calculated bivariate local Moran’s I indices. The statistical analysis examined the two largest clusters, i.e., the high–high and low–low clusters, and the results of the research indicate that the first four principal components explained 70.50% and 73.47% of the total variance, respectively. In the high–high cluster, the low rates of erosion reduction (average Index Z = 98) in the most significant types of rural settlements were determined according to demographic indicators (i.e., the higher population vitality and population density, the smaller share of the old population and the lower average age of the population) and the large proportion of arable land and Neogene sediments. In the low–low cluster, high erosion reduction rates were detected (average index Z = 64). In this cluster, the more statistically significant influence of natural conditions in combination with demographic–agrarian processes (i.e., the larger share of the old population, the higher average age of the population, the lower vitality index and deagrarization) were decisive factors in changing erosion intensity
Residential Building Stock in Serbia: Classification and Vulnerability for Seismic Risk Studies
Get PDFRegional seismic risk assessment is necessary for designing effective seismic risk mitigation measures. In general, such risk assessment studies consist of three components: hazard, vulnerability, and exposure modelling. This paper lays the foundations for regional seismic risk assessment of the residential building stock in Serbia and addresses each of the three seismic risk assessment components, either by reviewing the existing or proposing novel models. First, a review of seismic hazard models and seismic design codes used in Serbia in the past 70 years was presented. Next, an overview of Serbia’s population metrics and historical development of Serbian’s residential building stock was presented to provide the context for the exposure model. Furthermore, the paper proposed a novel building classification for Serbia's residential building stock, which is based on the existing building taxonomies, but it has been adapted to account for the local building characteristics. Building damage patterns reported in past earthquakes in Serbia and neighbouring countries were reviewed as a basis for damage classification pertaining to building typologies included in the proposed classification. Finally, the results of a preliminary vulnerability model were presented in the form of expert-based fragility functions derived for buildings typical of Serbia's residential building stock
Palace of Golubac Fortress
Get PDFThe Golubac Fortress was built at the very entrance of the Iron Gates gorge, at the point where the Danube is the widest in its course and transitions into the narrow passage of the Carpathian Mountains. The fortress represented an important medieval military border stronghold, strategically constructed due to the military significance of the location. Because of its position, during the 14th and 15th centuries, bordering countries, Hungary and Serbia, and later the Ottoman Empire, fought to conquer the Golubac Fortress in order to gain control and power over the state border.
There are no exact records of who and when initially built the Golubac Fortress. The first mention in written sources is from the year 1335, in a Hungarian charter from 1337, which states that the nobleman Nikola Banfi resided in Golubac in 1335. Until the dissolution of the Dušan’s Empire, Golubac Fortress status remains unchanged according to historical sources, and it remains in Hungarian possession.
At the beginning of the 21st century, the town of Golubac was in very poor condition, neglected and inaccessible. Reconstruction of the entire Golubac Fortress began in 2011. The reconstruction was officially completed in 2019. However, some minor reconstruction and revitalization work is still ongoing today.
The foundation of the Golubac Fortress was adapted to the terrain's configuration and consists of 9 towers connected by the ramparts and the Palace. As part of the restoration efforts, all the towers, ramparts, and the Palace were reconstructed.
The paper depicts the reconstruction of the entire Palace, including its foundations and a new roof structure made of glued laminated timber
Urban greenery’s effects on Public Health and Wellbeing of Citizens and how to assess it – preliminary euPOLIS findings
Get PDFMany studies report on the ability of natural environments and accessible green and blue
spaces in the cities to diminish climate change impacts and lower the possibility of disasters. However,
that is not the full extent of their effects. Among others, these urban spaces enhanced with nature-based
solutions (NBS) can support active recreation and allow places for relaxation and consolidation from daily
stress.
There is some evidence that NBS with their extensive greenery can give the positive impact on numerous
psychological and physiological outcomes. Urban areas rich in greenery and biodiversity provide great
opportunity for humans to come closer to nature and improve their health and well-being through
interaction with a variety of flora and fauna species. Specifically, there is evidence that mental health
(anxiety, stress levels) and psychological wellbeing may benefit from plant species richness (Fuller et al.,
2007), animal species richness (Dallimer et al., 2012) and soil biodiversity (Wall et al., 2015). Furthermore,
it has been shown that soil organisms, through their roles in controlling soil-borne pathogens and pests
(soil vitality) lessen the prevalence of allergic diseases (Wall et al. 2015). Replacing or restoring the soil,
regulation of water conditions, enabling plant species diversity - especially native ones, can substantially
increase soil biodiversity leading to recovery of the natural soil food web, so the pathogen risk would be
minimized with respect to communicable and non-communicable diseases (Crump et al., 2021). However,
urban green spaces can also be linked to negative health outcomes, such as allergic reactions, or vectorborne diseases, as the result of increased exposure to allergenic pollen or increased amount of disease
vectors in urban green environments (Calaza‐Martinez and Iglesias‐Díaz, 2016). These potential harmful
effects may be addressed through the adequate design, maintenance and management of urban green
spaces and selection of species.
Although different studies show some positive (or negative) effects of NBS on public health and wellbeing
(PH&WB), still it is a challenge to actually quantify the extent of the effects, and also attribute the quantity
to particular characteristics of an NBS. This is why EC has established a call topic SC5-14-2019 - Visionary
and integrated solutions to improve well-being and health in cities, to fund projects that will implement
different types of solutions that are capable of enhancing PH&WB in cities and assess their impacts. Once
demonstration sites are developed and assessed, key findings and indicators will be included in the already
available EC Handbook of indicators - Evaluating the impact of nature-based solutions: A handbook for
practitioners.
This paper presents preliminary findings in the endeavour to quantify urban greenery’s and biodiversity’s
effects on PH&WB, by integrating subjective, objective, physiological, and psychological monitoring
approaches and producing a multifaceted understanding that is essential for policymakers, urban planners,
and public health professionals to design sustainable and nature-inclusive cities that promote the wellbeing of their inhabitants
Damage of Masonry Infills in February 2023 Kahramanmaras Earthquakes and Isolation of Infill Walls as Potential Solution for the Future
No full textThe most dominant type of damage in the February 2023 Kahramanmaras earthquakes was the failure of infills walls. This paper shows just part of the effects of these earthquakes on the infills and concequences on the building inventory and people. The data was collected during the reconaissance field mission one month after the earthquake. In all cities visited damage of the infilled RC frame structures was devastating. Poor behaviour and heavy damage due to the interaction of flexible frames with the stiff infill walls showed that traditional infills (mortar connection between frame and infill) are conceptually wrong system for the buildings in earth-quake active areas. Beside heavy in-plane damage, inadequate connection between frames and infills led to the widespread out-of-plane collapse of infill walls. This has jeopardized people and escape routes during the earthquakes as well it produced significant economic loss. Many other earthqukes before showed that this is not acceptable anymore, but this one confirmed it. Therefore, this paper also proposes isolation of infill walls as a solution that can prevent such a devastating effects in future earthqaukes. Although isolation of infills is presribed in the codes it is not in use due to the fact that there are no simple and easy applicable solutions on the market. With the aim to fill this gap, a system presented here is developed. Its goal is to provide functional and easy applicable solution to the designers and construction companies and workers. Experimental tests on the full scale specimens of isolated infilled RC frames are shown, confirming the effectiveness of the isolation system. Infill walls with windows, doors and full walls are tested under various earthquake loading conditions. Furthermore, comparison with the traditional system was done, showing benefits and improvements brought by this system
Base Isolation as a Solution for Protecting the Laboratory Buildings and Equipment: A Case Study from Novi Sad, Serbia
No full textAs technology of base isolation is getting more popular, it also widens the fields of its application. It is logical to apply base isolation for very important structures (hospitals, schools, theatres, etc.), but it also becomes as a good solution for safety of buildings, and also people and content inside the structures with different fields of use. In that sense, use of base isolation in research centres, laboratories and institutes becomes more common. In the north of Serbia, in Novi Sad, a state-of-the-art research building is being built for the BioSense Institute with financial support from the European Union. The part of the building with laboratories is provided with base isolation with integrated structure-borne noise insulation to protect and ensure smooth operation of the highly sensitive and capital-intensive technical installations. In addition, the decoupled laboratory module of the research building is provided with BIM-based building monitoring in order to be able to query and assess changes in the condition of the building at any time. This paper described the design and steps of installation of base isolators. Furthermore, results of on-site measurements (before, during and after construction) are presented. Sliding isolation pendulum (SIP) isolators incorporating polyurethane plate are presented as a one-package solution for both seismic and vibration isolation. Main characteristics of the system are presented. Its ease of installation and effectiveness of such a system presents big potential for the use in practice for different cases in practice (theatres, metro stations, hospitals etc.)
Model of coordinated crowd dynamics
No full textThis paper presents a mathematical model of synchronisation of multiple people during cyclic activities such as walking, running, jumping and bouncing. Providing that quality models of individual loading for these activities do exist, the sync model is the key component towards an urgently needed yet reliable model of artificial dynamic loading due to multiple active occupants. A model proposed here describes the effect of external and internal factors on the crowd dynamics. The former includes periodic external stimuli on the body motion of individuals, such as perceptible vibration of the ground and music beats. The later addresses the mutual interaction between individuals, such as possibility to see, hear or touch each other. Modelling approach is inspired by the existing models of coupled pendulums while the governing equations feature Mathieu-type behaviour. For the sake of simplicity and efficiency, the model is kept linear and deterministic. All modelling parameters have a physical interpretation and their values can be calibrated to match experimental measurements
Transfer learning approach based on satellite image time series for the crop classification problem
No full textThis paper presents a transfer learning approach to the crop classification problem based on time series of images from the Sentinel-2 dataset labeled for two regions: Brittany (France) and Vojvodina (Serbia). During preprocessing, cloudy images are removed from the input data, the time series are interpolated over the time dimension, and additional remote sensing indices are calculated. We chose TransformerEncoder as the base model for knowledge transfer from source to target domain with French and Serbian data, respectively. Even more, the accuracy of the base model with the preprocessing step is improved by 2% when trained and evaluated on the French dataset. The transfer learning approach with fine-tuning of the pre-trained weights on the French dataset outperformed all other methods in terms of overall accuracy 0.94 and mean class recall 0.907 on the Serbian dataset. Our partially fine-tuned model improved recall of crop types that were poorly classified by the base model. In the case of sugar beet, class recall is improved by 85.71%