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Abstract

The aim of this paper is to answer the question: Are the Łódź Hills useful for electrical energy production from wind energy or not? Due to access to short-term data related to wind measurements (the period of 2008 and 2009) from a local meteorological station, the measure – correlate – predict approach have been applied. Long-term (1979‒2016) reference data were obtained from ECWMF
ERA-40 Reanalysis. Artificial neural networks were used to calculate predicted wind speed. The obtained average wind speed and wind power density was 4.21 ms⁻¹ and 70 Wm⁻¹, respectively, at 10 m above ground level (5.51 ms⁻¹, 170 Wm⁻¹ at 50 m). From the point of view of Polish wind conditions, Łódź Hills may be considered useful for wind power engineering.

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Authors and Affiliations

R. Korupczyński
J. Trajer
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Abstract

The structure of Austempered Ductile Iron (ADI) is depend of many factors at individual stages of casting production. There is a rich literature documenting research on the relationship between heat treatment and the resulting microstructure of cast alloy. A significant amount of research is conducted towards the use of IT tools for indications production parameters for thin-walled castings, allowing for the selection of selected process parameters in order to obtain the expected properties. At the same time, the selection of these parameters should make it possible to obtain as few defects as possible. The input parameters of the solver is chemical composition Determined by the previous system module. Target wall thickness and HB of the product determined by the user. The method used to implement the solver is the method of Particle Swarm Optimization (PSO). The developed IT tool was used to determine the parameters of heat treatment, which will ensure obtaining the expected value for hardness. In the first stage, the ADI cast iron heat treatment parameters proposed by the expert were used, in the next part of the experiment, the settings proposed by the system were used. Used of the proposed IT tool, it was possible to reduce the number of deficiencies by 3%. The use of the solver in the case of castings with a wall thickness of 25 mm and 41 mm allowed to indication of process parameters allowing to obtain minimum mechanical properties in accordance with the PN-EN 1564:2012 standard. The results obtained by the solver for the selected parameters were verified. The indicated parameters were used to conduct experimental research. The tests obtained as a result of the physical experiment are convergent with the data from the solver.
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Authors and Affiliations

K. Jaśkowiec
1 2
ORCID: ORCID
A. Opaliński
2
ORCID: ORCID
P. Kustra
2
D. Jach
3
D. Wilk-Kołodziejczyk
1 2
ORCID: ORCID

  1. Lukasiewicz Research Network-Krakow Institute of Technology, Poland
  2. AGH University of Science and Technology, Department of Applied Computer Science and Modelling, Poland
  3. Kutno Foundry, Poland
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Abstract

The paper is devoted to development of the evaluation methods tor limiting condition of metal alloys and steels under uniaxial and biaxial proportional and non-proportional low-cycle fatigue. To investigate the fatigue behavior of Type 08X 18H I OT stainless steels and titanium alloys BT9 strain controlled tests under 12 proportional and nonproportional loading ar room temperature were carried out. A strain parameter. namely, a nonproportional strain range. is proposed to obtain a correlative dependence with lifetime. For the majority or the materials this dependence can be derived from uniaxial tests and described by a linear function. It made it possible to propose simple engineering method for lifetime prediction.
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Authors and Affiliations

Sergey Shukayev
Mykhaylo Borodii
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Abstract

Weather forecasting requires knowledge of the laws of atmospheric movement. Apart from classic fluid mechanics, we must consider the rotational motion of our planet, the differential heating of its surface through the absorption of solar radiation, as well as water evaporation and condensation processes.

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Authors and Affiliations

Lech Łobocki
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Abstract

The aim of the presented investigations was to irnprovc the quality of CFO numerical modeling of the propagation of gaseous contaminations in a test laboratory with a tracer gas source and a local exhaust in general mixing ventilation. The investigations were carried out making use of experimental identification of the flow. Concise information is presented concerning the CFO method applied in the modeling of the airflow and gaseous contaminant. The tested object has been characterized, as well as its respective experimental data. The ways of generating its simulation model has been described, paying special attention to the simulation of the diffuser. TI1e results of prediction have been compared with the results of measurements of the air velocity and the concentration of gaseous contaminant. Attempts have been made to improve the quality of the obtained results of prediction of the distribution of tracer gas concentration by increasing the accuracy simulating the diffuser, the jct leaving the diffuser and the airflow pattern in surrounding the contarninant source and suction nozzle. It has also been tried to utilize the results of numerical prediction for the purpose of determining the effectiveness of the local exhaust.
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Authors and Affiliations

Barbara Lipska
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Abstract

In individual dogs, despite good quality of raw sperm, some parameters are significantly changed after thawing, which cannot be predicted. We therefore investigated whether motility parameters objectively obtained by CASA, membrane integrity (MI), cell morphology or a combination are suitable to improve the prediction of bad post-thaw quality. For this purpose 250 sperm analysis protocols from 141 healthy stud dogs, all patients introduced for sperm cryopreservation, were evaluated and a Classification and Regression Tree (CART) -analysis performed. The sperm was routinely collected, analysed, and frozen by using a modified Uppsala system. After thawing, data were routinely examined by using CASA, fluorescent microscopy for membrane integrity (MI) and Hancock’s fixation for evaluation of cell morphology. Samples were sorted by post-thaw progressive motility (P) in good (P > / = 50%, n=135) and bad freezers (P<50%, n=115). Among bad freezers, 73.9% showed in addition post-thaw total morphological abberations of >40% and/or MI <50%.

Bad freezers were significantly older than good freezers (p<0.05). Progressive motility (P), velocity curvilinear (VCL), mean coefficient (STR), and linear coefficient (LIN) were potential predictors for post-thaw sperm quality since specifity was best (85.8%) and sensitivity (75.4 %) and accuracy (80.4 %) good. For these objectively measured raw sperm parameters, cut-off values were calculated allowing prediction of bad post-thaw results with high accuracy: P = 83.1 % VCL = 161.3 µm/sec, STR = 0.83 %, and LIN = 0.48 %. Raw sperm samples with values below these cut off values will have below average post-thaw quality with a probability of 85.8%. We conclude that VCL, P, STR and LIN are potential predictors of the outcome of sperm cryopreservation, when combined.

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Authors and Affiliations

S. Schäfer-Somi
A. Tichy
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Abstract

Estimating the pathloss and signal strength of the transmitted signal at specific distances is one of the main objectives of network designers. This paper aims to provide generalized pathloss models appropriate for urban areas in Muscat the capital city of the Sultanate of Oman environment. The research includes studying different models of pathloss for the 4G cellular network at Muttrah Business District (MBD) at Muscat. Different models (Free Space model, Okumura Hata, Extended Sakagami, Cost231 Hata, ECC-33 Hata – Okumura extended, Ericsson, Egli, and SUI) are used with 800MHz. The results of the prediction models are compared with real measured data by calculating RMSE. The generalized models are created by modified original models to get accepted RMSE values. Different cells at MBD are tested by modified models. The RMSE values are then calculated for verification purposes. To validate the modified pathloss models of 4G, they are also applied at different cells in a different city in the capital. It has approximately the same environment as MBD. The modified pathloss models provided accepted predictions in new locations.
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Authors and Affiliations

Nawal Al-Aamri
1
Zia Nadir
1
Hassan Al-Lawati
1
Mohammed Bait Suwailam
1

  1. ECE Dept. at College of Engineering at SQU, Muscat, Sultanate of Oman
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Abstract

The existing traffic noise prediction models in road intersections relate mainly to the typical solutions of intersection geometry and traffic organisation. There are no models for large and more complex intersections such as signalised roundabouts. This paper presents the results of studies on the development of a traffic noise prediction model for this type of intersection. The model was developed using a multiple regression method based on the results of field measurements of traffic parameters and noise levels in the vicinity of signalised roundabouts in Poland. The obtained model consists of two groups of variables affecting noise levels at the intersection. The first group determines in detail the influence of traffic and geometry of the closest entry. The second group shows the influence of more distant noise sources (traffic at the three remaining entries of the intersection) and the influence of the dimensions of the entire intersection. The developed model was verified through additional field measurements, as well as compared to the results of two methods of traffic noise prediction: the French ‘NMPB-Routes-2008’ and the German ‘RLS-90’. The obtained results confirmed a higher accuracy of calculations performed using the developed model in the range of: −1.2 dB ÷ +1.0 dB, while the ‘NMPB-Routes-2008’ and ‘RLS-90’ calculate precision were respectively: −2.8 dB ÷ +1.3 dB, and +0.8 dB ÷ +5.2 dB. Therefore, the developed model allows for a more accurate prediction of noise levels in the vicinity of signalised roundabouts in a flat terrain without buildings and noise barriers.

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Authors and Affiliations

M. Motylewicz
W. Gardziejczyk
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Abstract

In the paper, we are analyzing and proposing an improvement to current tools and solutions for supporting fighting with COVID-19. We analyzed the most popular anti-covid tools and COVID prediction models. We addressed issues of secure data collection, prediction accuracy based on COVID models. What is most important, we proposed a solution for improving the prediction and contract tracing element in these applications. The proof of concept solution to support the fight against a global pandemic is presented, and the future possibilities for its development are discussed.
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Bibliography

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Authors and Affiliations

Martyna Gruda
1
Michal Kedziora
1

  1. Wroclaw University of Science and Technology, ul. Wybrzeże Stanisława Wyspiańskiego 27, 50-370 Wroclaw, Poland
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Abstract

The strip yield model from the NASGRO computer software has been applied to predict fatigue crack growth in two different aircraft aluminium alloys under constant amplitude loading and programmed and random variable amplitude load histories. The computation options realized included either of the two different strip yield model implementations available in NASGRO and two types of the input material data description. The model performance has been evaluated based on comparisons between the predicted and observed results. It is concluded that altogether unsatisfactory prediction quality stems from an inadequate constraint factor conception incorporated in the NASGRO models.
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Authors and Affiliations

Małgorzata Skorupa
Tomasz Machniewicz
Andrzej Skorupa
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Abstract

The Kuroshio Extension front (KEF) considerably influences the underwater acoustic environment; however, a knowledge gap persists regarding the acoustic predictions under the ocean front environment. This study utilized the high-resolution ocean reanalysis data (JCOPE2M, 1993–2022) to assess the impact of the KEF on the underwater acoustic environment. Oceanographic factors were extracted from the database using the Douglas-Peucker algorithm, and acoustic propagation characteristics were obtained using the Bellhop raytracing model. This study employed a backpropagation neural network to predict the acoustic propagation affected by the KEF. The depth of the acoustic channel axis and the vertical gradient of the transition layer of sound speed were identified as the fundamental factors influencing the first area of convergence, with correlations between the former and the distance of the first convergence zone ranging from 0.52 to 0.82, and that for the latter ranging from −0.42 to −0.7. The proposed method demonstrated efficacy in forecasting first convergence zone distances, predicting distances with less than 3 km error in >90% of cases and less than 1 km error in 68.61% of cases. Thus, this study provides a valuable predictive tool for studying underwater acoustic propagation in ocean front environments and informs further research.
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Authors and Affiliations

Weishuai Xu
1
Lei Zhang
2
Hua Wang
2

  1. No. 5 Student Team, Dalian Naval Academy Dalian, Liaoning, China
  2. Department of Military Oceanography and Hydrography and Cartography Dalian Naval Academy Dalian, Liaoning, China
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Abstract

High definition video transmission is one of the prime demands of modern day communication. Changing needs demand diverse features to be offered by the video codec standards, H.264 fits to these requirements for video compression. In this work, an attempt has been made to optimize the inter prediction along with improved intra prediction to ensure the minimal bit rates thereby reduction in the channel bandwidth, which is required in most of the wireless applications. In intraprediction, only DC prediction mode is chosen out of 9 modes with 4*4 luma blocks that reduces the coding complexity towards optimal logic utilization in order to support typical FPGA board for hardware implementation. Most significantly, Inter prediction is carried out utilizing the M9K blocks efficiently with proper timing synchronization to reduce the latency in the encoding operation. Experimental set up comprising of two Altera DE2-115 boards connected through Ethernet cable demonstrated the video transmission. These optimized intra prediction and inter prediction stages resulted in significant improvement in the video compression possessing good subjective quality and increased video compression.
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Bibliography

[1] Bernatin.T ,Sundari.G, “ Video compression based on Hybrid transform and quantization with Huffman coding for video codec”, International Conference on Control, Instrumentation, Communication and Computational Technologies (ICCICCT), pp 476-480,IEEE.
[2] The Evolution of H.264 From Codec to System Architecture, White Paper , VBrick Systems, December, 2010
[3] Arun Kumar Pradhan, Lalit Kumar Kanoje and BiswaRanjan Swain, 2013 “FPGA based High Performance CAVLC Implementation for H.264 Video Coding” International Journal of Computer Applications (0975 – 8887) Volume 69– No.10.
[4] Teng Wang, Chih-Kuang Chen, Qi-Hua Yang and Xin-An Wang (2012), “FPGA Implementation and Verification System of H.264/AVC Encoder for HDTV Applications”, Advances in CSIE, Springer-Verlag Berlin Heidelberg, Vol. 2, AISC 169, pp. 345-352
[5] Gwo-Long Li et al. (2013), “135-MHz258-K gates VLSI design for all-intra H.264/AVC scalable video encoder”, IEEE Trans. Very Large Scale Integr.(VLSI) Syst., Vol. 21, No. 4, pp. 636-647
[6] Kuo, H.-C., Wu, L.-C., Huang, H.-T., Hsu, S.-T. and Lin, Y.-L. (2013), “A low power high-performance H.264/AVC intra-frame encoder for 1080pHD video”, IEEE Trans. Very Large Scale Integr. (VLSI) Syst., Vol. 19, No. 6, pp. 925-938

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Authors and Affiliations

T. Bernatin
1
G. Sundari
1
Sahaya Anselin Nisha
1
M.S. Godwin Premi
1

  1. Sathyabama Institute of Science and Technology, India
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Abstract

The continuous growth of smart communities and ever-increasing demand of sending or storing videos, have led to consumption of huge amount of data. The video compression techniques are solving this emerging challenge. However, H.264 standard can be considered most notable, and it has proven to meet problematic requirements. The authors present (BPMM) as a novel efficient Intra prediction scheme. We can say that the creation of our proposed technique was in a phased manner; it's emerged as a proposal and achieved impressive results in the performance parameters as compression ratios, bit rates, and PSNR. Then in the second stage, we solved the challenges of overcoming the obstacle of encoding bits overhead. In this research, we try to address the final phase of the (BPMM) codec and to introduce our approach in a global manner through realization of decoding mechanism. For evaluation of our scheme, we utilized VHDL as a platform. Final results have proven our success to pass bottleneck of this phase, since the decoded videos have the same PSNR that our encoder tells us, while preserving steady compression ratio treating the overhead. We aspire our BPMM algorithm will be adopted as reference design of H.264 in the ITU.

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Authors and Affiliations

Sara Hamdy
Abdelhalim Zekry
Wael A. Mohamed
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Abstract

This paper studies an evacuation problem described by a leader-follower model with bounded confidence under predictive mechanisms. We design a control strategy in such a way that agents are guided by a leader, which follows the evacuation path. The proposed evacuation algorithm is based on Model Predictive Control (MPC) that uses the current and the past information of the system to predict future agents’ behaviors. It can be observed that, with MPC method, the leader-following consensus is obtained faster in comparison to the conventional optimal control technique. The effectiveness of the developed MPC evacuation algorithm with respect to different parameters and different time domains is illustrated by numerical examples.
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[24] L. Zhang, J. Wang, and Q. Shi: Multi-agent based modeling and simulating for evacuation process in stadium, Journal of Systems Science and Complexity, 27(3), (2014), 430–444, DOI: 10.1007/s11424-014-3029-5.
[25] Y. Zheng, B. Jia, X.-G. Li, and N. Zhu: Evacuation dynamics with fire spreading based on cellular automaton, Physica A: Statistical Mechanics and Its Applications, 390(18-19), (2011), 3147–3156, DOI: 10.1016/j.physa.2011.04.011.
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Authors and Affiliations

Ricardo Almeida
1
Ewa Girejko
2
Luís Machado
3 4
Agnieszka B. Malinowska
2
Natália Martins
1

  1. Center for Research and Development in Mathematics and Applications (CIDMA), Department of Mathematics, University of Aveiro, 3810–193 Aveiro, Portugal
  2. Faculty of Computer Science, Bialystok University of Technology, 15-351 Białystok, Poland
  3. Institute of Systems and Robotics, DEEC – UC, 3030-290 Coimbra, Portugal
  4. Department of Mathematics, University of Trás-os-Montes e Alto Douro (UTAD), 5000-801 Vila Real, Portugal
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Abstract

The paper is concerned with the presentation and analysis of the Dynamic Matrix Control (DMC) model predictive control algorithm with the representation of the process input trajectories by parametrised sums of Laguerre functions. First the formulation of the DMCL (DMC with Laguerre functions) algorithm is presented. The algorithm differs from the standard DMC one in the formulation of the decision variables of the optimization problem – coefficients of approximations by the Laguerre functions instead of control input values are these variables. Then the DMCL algorithm is applied to two multivariable benchmark problems to investigate properties of the algorithm and to provide a concise comparison with the standard DMC one. The problems with difficult dynamics are selected, which usually leads to longer prediction and control horizons. Benefits from using Laguerre functions were shown, especially evident for smaller sampling intervals.
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Bibliography

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Authors and Affiliations

Piotr Tatjewski
1

  1. Warsaw University of Technology, Nowowiejska15/19, 00-665 Warszawa, Poland
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Abstract

Electromagnetic mill installation for dry grinding represents a complex dynamical system that requires specially designed control system. The paper presents model-based predictive control which locates closed loop poles in arbitrary places. The controller performs as gain scheduling prototype where nonlinear model – artificial recurrent neural network, is parameterized with additional measurements and serves as a basis for local linear approximation. Application of such a concept to control electromagnetic mill load allows for stable performance of the installation and assures fulfilment of the product quality as well as the optimization of the energy consumption.

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Authors and Affiliations

Szymon Ogonowski
Dariusz Bismor
ORCID: ORCID
Zbigniew Ogonowski
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Abstract

In this study, the modified Sauer cavitation model and Kirchhoff-Ffowcs Williams and Hawkings (K-FWH) acoustic model were adopted to numerically simulate the unsteady cavitation flow field and the noise of a threedimensional NACA66 hydrofoil at a constant cavitation number. The aim of the study is to conduct and analyze the noise performance of a hydrofoil and also determine the characteristics of the sound pressure spectrum, sound power spectrum, and noise changes at different monitoring points. The noise change, sound pressure spectrum, and power spectrum characteristics were estimated at different monitoring points, such as the suction side, pressure side, and tail of the hydrofoil. The noise characteristics and change law of the NACA66 hydrofoil under a constant cavitation number are presented. The results show that hydrofoil cavitation takes on a certain degree of pulsation and periodicity. Under the condition of a constant cavitation number, as the attack angle increases, the cavitation area of the hydrofoil becomes longer and thicker, and the initial position of cavitation moves forward. When the inflow velocity increases, the cavitation noise and the cavitation area change more drastically and have a superposition tendency toward the downstream. The novelty is that the study presents important calculations and analyses regarding the noise performance of a hydrofoil, characteristics of the sound pressure spectrum, and sound power spectrum and noise changes at different monitoring points. The article may be useful for specialists in the field of engineering and physics.
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Authors and Affiliations

He Xiaohui
1
Liu Zhongle
2
Yang Chao
1
Yuan Zhiyong
2

  1. Jiangnan Industry Group Co., Ltd., Wuyi Village, China
  2. Naval University of Engineering, Wuhan, China
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Abstract

Kidney Cooling Jacket (KCJ) preserves the kidney graft, wrapped in the jacket, against the too fast time of temperature rise during the operation of connecting a cooled transplant to the patient’s bloodstream. The efficiency of KCJ depends on the stationarity of the fluid flow and its spatial uniformity. In this paper, the fluid velocity field inside the three different KCJ prototypes has been measured using the 20 MHz ultrasonic Doppler flowmeter. The simplified 2D geometrical model of the prototypes has been presented using COMSOL Multiphysics to simulate the fluid flow assuming the laminar flow model. By comparing the numerical results with experimental data, the simplified 2D model is shown to be accurate enough to predict the flow distribution of the internal fluid velocity field within the KCJ. The discrepancy between the average velocity measured using the 20 MHz Doppler and numerical results was mainly related to the sensitivity of the velocity measurements to a change of the direction of the local fluid flow stream. Flux direction and average velocity were additionally confirmed by using commercial colour Doppler imaging scanner. The current approach showed nearly 90% agreement of the experimental results and numerical simulations. It was important for justifying the use of numerical modelling in designing the baffles distribution (internal walls in the flow space) for obtaining the most spatially uniform field of flow velocity.
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Authors and Affiliations

Barbara Gambin
1
ORCID: ORCID
Ilona Korczak-Cegielska
2
Wojciech Secomski
1
Eleonora Kruglenko
1
Andrzej Nowicki
1

  1. Department of Ultrasound, Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
  2. Doctoral Studies of Institute of Fundamental Technological Research, Polish Academy of Sciences, Warsaw, Poland
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Abstract

This study was conducted to predict the yield and biomass of lentil (Lens culinaris L.) affected by weeds using artificial neural network and multiple regression models. Systematic sampling was done at 184 sampling points at the 8-leaf to early-flowering and at lentil maturity. The weed density and height as well as canopy cover of the weeds and lentil were measured in the first sampling stage. In addition, weed species richness, diversity and evenness were calculated. The measured variables in the first sampling stage were considered as predictive variables. In the second sampling stage, lentil yield and biomass dry weight were recorded at the same sampling points as the first sampling stage. The lentil yield and biomass were considered as dependent variables. The model input data included the total raw and standardized variables of the first sampling stage, as well as the raw and standardized variables with a significant relationship to the lentil yield and biomass extracted from stepwise regression and correlation methods. The results showed that neural network prediction accuracy was significantly more than multiple regression. The best network in predicting yield of lentil was the principal component analysis network (PCA), made from total standardized data, with a correlation coefficient of 80% and normalized root mean square error of 5.85%. These values in the best network (a PCA neural network made from standardized data with significant relationship to lentil biomass) were 79% and 11.36% for lentil biomass prediction, respectively. Our results generally showed that the neural network approach could be used effectively in lentil yield prediction under weed interference conditions.

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Authors and Affiliations

Alireza Bagheri
Negin Zargarian
Farzad Mondani
Iraj Nosratti
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Abstract

The most worldwide method of liquidating underground hard coal mines is by spontaneous flooding as the result of the discontinuation of the rock mass drainage. Due to the hydrological reconstruction of the previously disturbed water system by mining operations, the movements of the rock mass with the opposite direction than subsidence appear. These movements are called rock mass uplift. This paper aims to present possible hazards related to land surface objects and the environment, which can appear during the flooding of the underground mine. The issue of proper forecasting of this phenomenon has so far been marginal in world literature. To date, only a few analytical methods have been used to predict the possible effects of surface deformation. Nowadays, the most common analytical method of forecasting surface deformation caused by the liquidation of underground workings by flooding is Sroka’s method. In this paper, the authors have presented analyses of flooding scenarios developed for a Polish mine and their impact on the land surface as well as the environment. The scenarios presented in the manuscript were selected for analysis as the most probable concerning the mine and the future plans of the mining enterprise. The process of flooding coal mines results in several risks for surface objects and underground infrastructure. This is why the uplift caused by the flooding of the mine should be predicted. The resulting uplifting movements can also, apart continuous deformation lead to the creation of much more dangerous phenomena involving discontinuous deformations.
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Authors and Affiliations

Mateusz Dudek
1
ORCID: ORCID
Krzysztof Tajduś
1
ORCID: ORCID
Janusz Rusek
2
ORCID: ORCID

  1. Strata Mechanics Research Institute, Polish Academy of Sciences, ul. Reymonta 27, 30-059 Cracow, Poland
  2. Faculty of Mining Surveying and Environmental Engineering, AGH University of Science and Technology, al. Mickiewicza 30, 30-059 Cracow, Poland
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Abstract

This paper investigates the application of a novel Model Predictive Control structure for the drive system with an induction motor. The proposed controller has a cascade-free structure that consists of a vector of electromagnetics (torque, flux) and mechanical (speed) states of the system. The long-horizon version of the MPC is investigated in the paper. In order to reduce the computational complexity of the algorithm, an explicit version is applied. The influence of different factors (length of the control and predictive horizon, values of weights) on the performance of the drive system is investigated. The effectiveness of the proposed approach is validated by some experimental tests.

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Authors and Affiliations

Karol Tomasz Wróbel
Krzysztof Szabat
ORCID: ORCID
Piotr Serkies
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Abstract

The model predictive current control (MPCC) of the permanent magnet synchronous motor (PMSM) is highly dependent on motor parameters, and a parameter mismatch will cause the system performance degradation. Therefore, a strategy based on an internal model control (IMC) observer is proposed to correct the mismatch parameters. Firstly, based on the MPCC strategy of the PMSM, according to the dynamic model of the PMSM in a rotating orthogonal coordinate system, d-axis and q-axis current IMC observers are designed, and the stability derivation is carried out. It is proved that the observer can estimate d-axis and q-axis disturbance components caused by a parameter mismatch without static error. Then, the estimated disturbance component is compensated for by the reference voltage prediction expression. Finally, the effectiveness of the proposed strategy is verified in two different conditions. The experimental results show that the proposed control strategy can effectively compensate for the parameter mismatch disturbance in MPCC for PMSM, improve the dynamic and static performance of the system, and improve the robustness of the system.
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Authors and Affiliations

Min'an Tang
1
Chenyu Wang
1
Yinhang Luo
1
ORCID: ORCID

  1. School of Automation and Electrical Engineering, Lanzhou Jiaotong University, China No. 88, Anning West Road, Anning District, Lanzhou City, Gansu Province, China
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Abstract

The objective of the present work was to evaluate the hydrodynamic behaviour of a stratified bed filtration column consisting of 4 cm of sand and 2 cm of limestone to remove turbidity and measuring the head loss through the filter in several runs. In this study, two types of sand were used as filtering bed material, one fine and one medium. Crushed limestone was also available. These materials were characterized to determine the average particle diameter, porosity, and permeability coefficient. These were respectively 1.7∙10 –4 m, 336.96 and 0.68 m∙day –1 for fine sand, 3.3∙10 –4 m, 654.24 and 2.59 m∙day –1 for the medium sand and 1.26∙10–3 m, 388.8 and 8.64 m∙day–1 for crushed limestone. Using these materials, hydrodynamic analyses were carried out using clean water under rapid filtration conditions. In these analyses, different filtration rates were determined to be used in each experiment. Once the filtration rates were determined, the filtration analysis was performed with synthetic turbid water prepared at 8 NTU using tap water and bentonite. From the results obtained, a predictive model was developed based on total head losses for the evaluated filter, maintaining the rapid filtration condition. As a result, a turbidity removal efficiency of 97.7% was obtained with a total head loss of 17.8 cm at a filtration rate of 153 m·day –1. The developed model predicted head loss as a function of operating time, filtration rate, and filter depth to maximise turbidity removal. The model showed excellent prediction accuracy with R2 of 0.9999, which indicates that the model predictions are not biased. It was concluded that, due to the porosity of these materials, a stratified bed of sedimentary rocks has a great potential to be used in surface water filtration processes, which implies that it could be used at the rural community level as a form of water treatment, since the
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Authors and Affiliations

Candelaria N. Tejada-Tovar
1
ORCID: ORCID
Ángel Villabona-Ortíz
1
ORCID: ORCID
David López-Barbosa
1
ORCID: ORCID

  1. Universidad de Cartagena, Faculty of Engineering, Chemical Engineering Department, Avenida del Consulado St. #30 No. 48 152, 130015, Cartagena, Colombia
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Abstract

The Lithuanian national standard of electric resistance is maintained as the basis for calibration and measurement capabilities published in the key comparison database of the International Bureau of Weights and Measures (BIPM). The stability and uncertainty of the resistance value measurements, performed since 2004 using the calibrated values of the standard resistors to predict their future behaviour as well as influence of environmental conditions, are discussed. Also discussed is the recovery of a standard resistor which had undergone a mechanical disturbance. It is concluded that the standard resistors operated by the Lithuanian National Electrical Standards Laboratory feature stable drift of resistance, which is well predicted by means of linear regression.

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Authors and Affiliations

Andrius Bartašiunas
Rimantas Miškinis
Dmitrij Smirnov
Emilis Urba

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