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Using the trendlines of an acceleration response as a tool to decompose a structural response is a new topic that was proposed by authors in 2020. This paper provides a numerical/experimental investigation of using a Savitzky–Golay filter (SGF) in a method to calculate the trendline and decompose building acceleration responses when subjected to a seismic load. Hence, this paper proposes an output-only, energy-based, damage detection method in which the trend lines of a building's structural acceleration responses are used to locate the damage. For this purpose, an adjusted SGF is utilized to calculate an especial trend line for each floor's acceleration response of the building structural model. The energy of these trend lines is then calculated and normalized. Two damage indices are used, of which, the second one is being proposed for the first time in this paper. The accuracy of the proposed method is numerically and experimentally investigated using a five-floor building structural model subjected to white noise excitation through a shake table. The results prove that the proposed method is capable of accurately locating and quantifying structural damages with a severity of more than 10% in a noisy environment. In view that the proposed method locates the damage with no need of determining the structural modal properties or parameters, it can be categorized as an online and quick structural damage detection method. [ABSTRACT FROM AUTHOR]

In severe low-visibility environments full of smoke, because of the performance degeneration of the near-infrared (NIR) collimation system of quantum drones communication networks, the improved dual-threshold method based on trend line analysis for long-wave infrared (LWIR) quantum cascade lasers (QCLs) is proposed, to achieve target acquisition. The simulation results show that smoke-scattering noise is a steeply varying medium–high-frequency modulation. At particle sizes less than 4 μ m, the traditional dual-threshold method can effectively distinguish the target information from the smoke noise, which is the advantage of the LWIR laser compared to the NIR laser. For detecting lasers with high signal-to-noise ratios (SNRs), the method can achieve good target acquisition, by setting reasonable conventional thresholds, such as 0.7 times the peak intensity and 0.8 times the peak rising velocity. At low SNRs and steep intensity variation, the method can also achieve good target acquisition, by adaptively resetting new thresholds after filtering the detecting laser, such as 0.6 times the peak intensity and 0.6 times the peak rising velocity. The results of this paper will provide a reference for the performance improvement and refinement of the collimation system for wireless quantum communication networks in low visibility. [ABSTRACT FROM AUTHOR]

The research subject is the analysis of the impact of the value of realized investments in new fixed assets on the gross domestic product (GDP) of Serbia in the period from 2012 to 2021. The research was conducted with the aim of determining which economic activity, according to the value of realized investments, contributes the most to the creation of the value of Serbia’s GDP. The defined goal was realized by applying the multiple regression method, and the starting model contained the value of realized investments in four activities, which are: manufacturing; electricity, gas, steam and air conditioning supply; transportation and storage; agriculture, forestry and fishing. The occurrence of multicollinearity between independent variables was checked by the tolerance coefficient, VIF coefficients and Eigen values, and their values indicate the presence of weak multicollinearity, which is a consequence of the impact of realized investments in agriculture, forestry and fishing. The result of the set regression model shows that the greatest contribution to the creation of Serbia’s GDP is made by the realized investment value in the electricity, gas, steam and air conditioning supply (Standardized Beta Coefficients 0.687, Sig. = 0.012).

The research subject is the analysis of the impact of the value of realized investments in new fixed assets on the gross domestic product (GDP) of Serbia in the period from 2012 to 2021. The research was conducted with the aim of determining which economic activity, according to the value of realized investments, contributes the most to the creation of the value of Serbia’s GDP. The defined goal was realized by applying the multiple regression method, and the starting model contained the value of realized investments in four activities, which are: manufacturing; electricity, gas, steam and air conditioning supply; transportation and storage; agriculture, forestry and fishing. The occurrence of multicollinearity between independent variables was checked by the tolerance coefficient, VIF coefficients and Eigen values, and their values indicate the presence of weak multicollinearity, which is a consequence of the impact of realized investments in agriculture, forestry and fishing. The result of the set regression model shows that the greatest contribution to the creation of Serbia’s GDP is made by the realized investment value in the electricity, gas, steam and air conditioning supply (Standardized Beta Coefficients 0.687, Sig. = 0.012). [ABSTRACT FROM AUTHOR]

X-class solar flares, which occurred in the daytime from 2008 to 2016 during solar cycle 24, were studied for their influence on the lower ionosphere over the lowequatorial Indian region. To understand the D-region behaviour during flare events, we used the very low frequency (VLF) navigational transmitter NWC (19.8 kHz) signal recorded at Pryagraj, Uttar Pradesh, India. A total of seven parameters were estimated: (i) the magnitude of X-ray flux, (ii) VLF signal rising amplitude perturbation (SRAP), (iii) X-ray flux and NWC signal start time difference (STD), (iv) peak time difference (PTD), (v) Wait’s ionospheric parameters h′ (reference height), (vi) β (sharpness factor) and (vii) D-region electron density difference (EDD) to determine the overall effect of solar flares on the D-region. The results suggest that three parameters (X-ray flux, SRAP and h′) show a decreasing trend through the linear fit line, two parameters (β and EDD) show an increasing trend, while the remaining two parameters show a mixed trend (decrease during low activity and increase during high activity). Further, the trend line during the diurnal variation shows an increasing trend for X-ray flux, PTD and h′, and a decreasing trend for SRAP, STD, β and EDD. Deviation in the case of individual events may indicate the dependence of these parameters on the seasons as well. The present study will provide the base for more robust analysis and modelling work in the future to understand the complexity of ionospheric change during flare events, and to develop a predictive model for space weather mitigation. [ABSTRACT FROM AUTHOR]

Using the trendlines of an acceleration response as a tool to decompose a structural response is a new topic that was proposed by authors in 2020. This paper provides a numerical/experimental investigation of using a Savitzky–Golay filter (SGF) in a method to calculate the trendline and decompose building acceleration responses when subjected to a seismic load. Hence, this paper proposes an output-only, energy-based, damage detection method in which the trend lines of a building’s structural acceleration responses are used to locate the damage. For this purpose, an adjusted SGF is utilized to calculate an especial trend line for each floor’s acceleration response of the building structural model. The energy of these trend lines is then calculated and normalized. Two damage indices are used, of which, the second one is being proposed for the first time in this paper. The accuracy of the proposed method is numerically and experimentally investigated using a five-floor building structural model subjected to white noise excitation through a shake table. The results prove that the proposed method is capable of accurately locating and quantifying structural damages with a severity of more than 10% in a noisy environment. In view that the proposed method locates the damage with no need of determining the structural modal properties or parameters, it can be categorized as an online and quick structural damage detection method.

In severe low-visibility environments full of smoke, because of the performance degeneration of the near-infrared (NIR) collimation system of quantum drones communication networks, the improved dual-threshold method based on trend line analysis for long-wave infrared (LWIR) quantum cascade lasers (QCLs) is proposed, to achieve target acquisition. The simulation results show that smoke-scattering noise is a steeply varying medium–high-frequency modulation. At particle sizes less than 4 μm, the traditional dual-threshold method can effectively distinguish the target information from the smoke noise, which is the advantage of the LWIR laser compared to the NIR laser. For detecting lasers with high signal-to-noise ratios (SNRs), the method can achieve good target acquisition, by setting reasonable conventional thresholds, such as 0.7 times the peak intensity and 0.8 times the peak rising velocity. At low SNRs and steep intensity variation, the method can also achieve good target acquisition, by adaptively resetting new thresholds after filtering the detecting laser, such as 0.6 times the peak intensity and 0.6 times the peak rising velocity. The results of this paper will provide a reference for the performance improvement and refinement of the collimation system for wireless quantum communication networks in low visibility.

A closure dam was constructed on Little Feni River at Musapur Union, Noakhali District by Bangladesh Water Development Board (BWDB) in 2016. The study assessed crop production fluctuations between pre and post period of the construction of this dam. Data were collected from Department of Agricultural Extension (DAE), Companiganj Upazila, and BWDB, Noakhali. Besides, an inception meeting was arranged at DAE with different participants for two consecutive days and three focused group discussions (FGD) from almost all stakeholders were done to triangulate the result. The trend was calculated by the data retrieved from 2011 to 2018 for the projection of the study. The result showed a revolutionary increasing trend for Brassica juncea, Arachis hypogaea, and Allium sativum with 1214%, 1400%, and 1600%, respectively. Followed by, the positive trend was showed for Oryza sativa, Cajanus cajan, Pisum sativum, Capsicum annuum, wintry vegetables and Cucumis sativus with 30.97%, 116.41%, 200%, 145.83%, 52%, 475%, respectively. And nearly stable trend was found for Ipomoea batatas, spices and Lathyrus sativus with a positive trend of 4%, negative trend of 7.59% and 8.86%, respectively. The study concluded that construction of closure dam might be greatly influenced in the high production rate of crops in the study area. [ABSTRACT FROM AUTHOR]

Today economic forecasts are necessary to identify possible goals of business and society development in general. Available models of information processes of economic system functioning differ by methods of mathematic tools usage. The degree of algorithm complexity with regard to their advantages and drawbacks cannot give an opportunity to choose one method without certain changes. For example, when the trend line is plotted usually only one economic indicator is used, however practice shows that in forecasting it is necessary to take into account several interdependent factors. Standard applied software products are rather expensive and to resolve the set tasks some additional instrumental means, tuning and users’ training are needed. The article proposes a method of plotting the trend line for several economic indicators simultaneously by using tools of widely spread software. The results of using the method for finding the common trend line for the rate of Euro to Russian ruble and the cost of oil barrel (3D) were shown. Apart from that the mathematic instrument for n-dimension case, which later could allow us to assess the possibility of changing several economic indicators at once and analyze their mutual impact.

In this paper we have analyzed an approach to assessing the relationship between some characteristics of the net panels forming the rope/net cone of a fishing trawl. Using the mathematical relationship of solidity ratios for the rope/net panels, it is possible to analyze existing structures and, furthermore, reduce the time for selecting the prototype trawl. Such mathematical relationship allows faster calculation of new trawl designs which takes into account the production specifics of an enterprise manufacturing the trawl fishing gear. The use of mathematical relationships provides the opportunity to accelerate the process of trawl construction.

The stable development of the economic sphere in Kazakhstan is more dependent on the state of the financial market, including the development of the domestic credit market. A well-developed credit market serves as the basis for production growth, increases the volume of trade, is a mechanism for implementing various strategic programs for innovative and technological modernization of industrial enterprises.In this work, a correlation analysis of factors affecting the profitability indicators of the banking structures of the Republic of Kazakhstan was carried out, which made it possible to attempt to build a multiple regression model to predict some parameters of the credit market in Kazakhstan for 2019-2023: the volume of consumer loans of banks, the number of loans to small businesses, indicators of deposits in banks, profitability of the country’s banking sector. The use of correlation and regression research methods regarding some parameters of the further development of the credit market ofthe Republic of Kazakhstan made it possible to build forecast values for the further development of the credit market as the financial basis for the progressive development of the national economy.

• The EDMD can be more applicable to actual scenarios than difference mode decomposition. • The TPE can eliminate the influence of the amplitude distortion of the noise spectrum caused by the transfer function. • The initial weight calculation strategy can greatly speed up the calculation speed of the proposed method. Difference mode decomposition (DMD) is an effective technique for accurately separating a signal into fault, natural, and noise components. However, DMD relies on the assumption that noise spectral lines have zero amplitude, making it less effective in cases with a low signal-to-noise ratio. In practical scenarios, signals from bearing faults are often weak and can get buried under strong noise due to the influence of the transmission path (TP). To broaden the application scope of DMD, we proposed the ensemble DMD (EDMD) method, incorporating the transmission path elimination (TPE) technology. Firstly, an Intrinsic time-scale decomposition (ITD)-based TPE approach is proposed to reduce the influence of excessive noise spectral line amplitude caused by the TP. Secondly, calculating the average of the difference between two kinds of normalized Fourier spectrums and using it as the initial weight of EDMD can improve the operation speed of EDMD. Finally, the signal with the transmission path eliminated is input to the EDMD to extract the faulty signal. Simulation and experimental verification demonstrate the capability of this method in accurately extracting fault features in rolling bearings and gears under the influence of the TP. [ABSTRACT FROM AUTHOR]

The occurrence of a hydraulic connection between piezometers is identified based on similar changes in water levels. Some piezometers react to changing upper or lower water levels, some may also react to atmospheric precipitation. If the reaction to variable upper water levels is significant, then leakage of seepage control devices is identified and the dam is subjected to repair works. The aim of this research paper is to present and analyse the dynamics of variability of water levels in open piezometers of the Chańcza dam, located at the 36 km of the Czarna Staszowska River in the town of Korytnica in Świętokrzyskie province (Poland). Before the analysis of the piezometric data was commenced, the Grubbs statistical test was used to identify and reject the outliers. The scope of the research includes the data captured between January 14, 2014 and January 13, 2017. A hypothesis was formulated that the change in the trend occurred after the spring of 2015 when the water level in the reservoir was reduced by approx. 1.5 m. Two trend lines were adapted for the water levels of each piezometer using the least squares method – the first one for the period from January 2014 to May 2015, and the second one from June 2015 to January 2017. In this way, two slopes of the linear function were obtained together with an estimation of their errors. These slopes were compared using a statistical parallelism test.

The biological characteristics and intraspecific variability of threespine stickleback, Gasterosteus аculeatus, from the estuary of the River Tuloma and lakes Venzin and Kulonga on the Kola Peninsula have been studied. Four morphotypes of threespine stickleback (trachurus with a keel, semiarmatus with а keel, leiurus with а keel, leiurus without keel) have been discovered. There are differences in the number of plates on the body of the stickleback, of plastic traits in different habitats, namely length and body height, the length of the first dorsal, middle dorsal and ventral spines. In the lakes there are morphs with a small number of plates, namely leiurus (3–6), and semiarmatus (13–16). In the estuary of the River Tuloma, the morphotype of trachurus with keel (22–26) is mostly found. The size and weight parameters of stickleback are also different in the investigated water bodies. On average, the length of freshwater stickleback is 53 mm, and the weight is 1.3 g, seawater stickleback, respectively, 72 mm and 4.4 g. These differences point to the adaptation to living in different conditions. In fresh reservoirs, the bone carapace is relieved by reducing the number of plates, while in water with a lower salinity, it is more difficult to extract the calcium needed to build bone plates, than in water with increased salinity. In the estuary of the River Tuloma during the tides there is an increase in salinity from 1 to 22 ‰, therefore, to extract calcium for building these scutes is more easily. Also, many-plate individuals after grasping by predators experience less damage than low-plate, and consequently the chances of escaping from the teeth of a predator increase. The dependence of the size-weight characteristics approximated by the power function equation of the form W = aLb has been determined. The coefficient b > 3 indicates the preservation of the shape of the body as the stickleback grows, and suggests that the rate of increment of mass is similar in the studied reservoirs.

This paper aims to analyze the changes in the trends of water levels in closed piezometers installed in the largest dam in Poland, i.e. Solina Dam located in the Podkarpackie province. The scope of the research includes the analysis of water levels in piezometers in the study period between 2010 and 2015. Statistical tests for identifying and rejecting outliers were performed before carrying out the analysis of the data acquired from the Automatic Technical Dam Monitoring System including: two variants of the Q-Dixon’s test (denoted as N9 and N13), as well as Grubbs’ test and Hampel’s test. A hypothesis was formulated that a change in the trend occurred after the floodin 2010. Using the least squares method , for each piezometer, two trend lines were matched to their water levels – the firstone for the year 2010 and the second one for the period of 2011–2015. In this way, two slope coefficientof the linear function were obtained, together with the estimation of their errors. These slopes were compared using a statistical parallelism test.

The numerical modelling of chloride penetration into concrete is very sensitive to the correct description of the input data. In the recent era, high-performance concrete (HPC), which combines Portland cement and other supplementary cementitious materials, has been gaining attraction due to their desirable material properties and durability. The presented results show the application of the modified approach for the evaluation of the suitability of the time-dependent model for the variation of the diffusion coefficient. The 26 various binary and ternary-based concrete mixtures blended with volcanic pumice pozzolan (VPP) as a major supplementary cementitious material (SCM) are compared with the reference Ordinary Portland Cement mixture. Other SCMs namely fly ash, slag, silica fume, and metakaolin were also utilized in ternary-based concrete mixtures. In-depth statistical analysis was carried out to show the variability and effects of the amount of the volcanic pumice as an SCM on the diffusion coefficient. The mean value and regression via linear approximation of the time-dependent coefficient of variation of the diffusion coefficients were used as well as the Root of Mean Squared Error approach. The presented results are suitable as the component of the input parameters for the durability-related probabilistic assessment of the reinforced concrete structures exposed to chlorides. In addition, the time-dependent ultimate limit state-related data was presented.

This paper focuses on optimization of signal quality in DWDM transmission systems with 128x10 channels considering channel spacing of 100GHz. It is well established that Amplified Spontaneous Emission (ASE) and nonlinearities are two main drawbacks in long haul optical fiber communications. Both of them can be mitigated using Hybrid Optical Amplifiers (HOA). In our work we used OptiSytem 13.0 simulator to perform the optimizations of DWDM transmission systems. We considered three different HOA configurations and calculated signal quality with respect to channel input power, minimum log of Bit Error Rate (BER), maximum eye opening factor. Furthermore we plotted the trend line which can be used to predict the performance of long haul optical fiber communications in case of three different hybrid optical amplifiers deployment scenarios. It is found that H3 (EDFA-RAMANOA) configuration covers 128 channels with optimum channel input power of -5dBm for 17.11dB signal quality. Moreover it is substantially evident by the trend lines and eye opening diagrams that the plotted performance comparison results of HOA are in accordance. [ABSTRACT FROM AUTHOR]

The Savitzky–Golay filter (SGF) is a time-domain technique that determines a trend line for a signal. The direct application of SGF for damage localization and quantification is investigated in this paper. Therefore, a single-stage trend line-based damage detection method employing SGF is proposed in which the damage is located and quantified at the bridge under moving load. A simply supported beam under moving sprung mass is numerically simulated to verify the proposed method. Four different velocities and five different single- and multi-damage scenarios are considered. The acceleration data along the beam are obtained, manually polluted with noise and their trend lines are then determined using SGF. The results show that the proposed method can accurately locate and quantify the damage using these trend lines. It is proved that the proposed method is insensitive to the noise and velocity variation in which having a constant velocity is a hard task before and after damage. Additionally, defining a normalization factor and fitting a Gaussian curve to this factor provide an estimation for the baseline and therefore, it categorizes the proposed method as baseline-free method.

The numerical modelling of chloride penetration into concrete requires sound description of input parameters. One of the crucial inputs is the diffusion coefficient of concrete. The concrete is heterogeneous material and its parameters depend on the level of maturity. Therefore, the objective of this work is to describe the time dependent variability of the diffusion coefficient of chlorides into concrete. Computation of the diffusion coefficient is based on the non-destructive testing of bulk electrical resistivity following ASTM C1760 standard and Nernst-Einstein relationship. The presented results show the variation of diffusion coefficient of control OPC mixture and 32 various binary and ternary concrete mixtures where the effect of prolonged aging is even more significant. Two possibilities of the time dependent diffusion coefficient probabilistic model based on coefficient variation (mean value and regression via linear approximation) are proposed. The quality of both approaches is evaluated using Root of Mean Squared Error approach. Overall, this study provides guidance to select proper statistical tool for the assessing the time dependent variation of diffusion coefficient. [ABSTRACT FROM AUTHOR]

This paper aims to analyze the changes in the trends of water levels in closed piezometers installed in the largest dam in Poland, i.e. Solina Dam located in the Podkarpackie province. The scope of the research includes the analysis of water levels in piezometers in the study period between 2010 and 2015. Statistical tests for identifying and rejecting outliers were performed before carrying out the analysis of the data acquired from the Automatic Technical Dam Monitoring System including: two variants of the Q-Dixon's test (denoted as N9 and N13), as well as Grubb's test and Hampel's test. A hypothesis was formulated that a change in the trend occurred after the flood in 2010. Using the least squares method , for each piezometer, two trend lines were matched to their water levels - the first one for the year 2010 and the second one for the period of 2011-2015. In this way, two slope coefficients of the linear function were obtained, together with the estimation of their errors. These slopes were compared using a statistical parallelism test. [ABSTRACT FROM AUTHOR]