Autor: Tiwari, M. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Water demand forecasting using extreme learning machines
Przewidywanie zapotrzebowania na wodę z użyciem technik uczenia maszynowego
Autorzy:: Tiwari, M.
Adamowski, J.
Adamowski, K.
Powiązania:: https://bibliotekanauki.pl/articles/292339.pdf
Data publikacji:: 2016
Wydawca:: Instytut Technologiczno-Przyrodniczy
Tematy:: artificial neural networks
bootstrap
Canada
extreme learning machines
uncertainty
water demand forecasting
wavelets
ekstremalne maszyny uczące się
falki
Kanada
niepewność
prognozowanie zapotrzebowania na wodę
sztuczne sieci neuronowe
Opis:: The capacity of recently-developed extreme learning machine (ELM) modelling approaches in forecasting daily urban water demand from limited data, alone or in concert with wavelet analysis (W) or bootstrap (B) methods (i.e., ELM, ELM_W, ELM_B), was assessed, and compared to that of equivalent traditional artificial neural network-based models (i.e., ANN, ANN_W, ANN_B). The urban water demand forecasting models were developed using 3-year water demand and climate datasets for the city of Calgary, Alberta, Canada. While the hybrid ELM_B and ANN_B models provided satisfactory 1-day lead-time forecasts of similar accuracy, the ANN_W and ELM_W models provided greater accuracy, with the ELM_W model outperforming the ANN_W model. Significant improvement in peak urban water demand prediction was only achieved with the ELM_W model. The superiority of the ELM_W model over both the ANN_W or ANN_B models demonstrated the significant role of wavelet transformation in improving the overall performance of the urban water demand model.
Oceniono zdolność modelowania z użyciem ekstremalnej maszyny uczącej się (ELM) stosowanej samodzielnie bądź w połączeniu z analizą falkową (W) lub metodami bootstrapowymi (B) (tzn. ELM, ELM_W, ELM_B) do przewidywania dobowego zapotrzebowania na wodę w mieście. Wyniki porównano z uzyskanymi tradycyjnymi metodami bazującymi na sztucznych sieciach neuronowych (tzn. ANN, ANN_W, ANN_B). Modele przewidujące zapotrzebowanie na wodę zbudowano z wykorzystaniem trzyletniego zapotrzebowania na wodę i zestawu danych klimatycznych dla miasta Calgary w kanadyjskiej prowincji Alberta. Hybrydowe modele ELM_B i ANN_B zapewniały satysfakcjonujące prognozy jednodniowe o podobnej dokładności, natomiast wyniki uzyskane z zastosowaniem modeli ELM_W i ANN_W były bardziej dokładne, przy czym model ELM_W okazał się lepszy niż ANN_W. Istotną poprawę prognozowania szczytowego zapotrzebowania na wodę w mieście uzyskano jedynie z zastosowaniem modelu ELM_W. Wyższość modelu ELM_W nad modelami ANN_W czy ANN_B dowodzi znaczącej roli transformacji falkowej w usprawnianiu działania modeli prognozujących zapotrzebowanie na wodę w mieście.
Źródło:: Journal of Water and Land Development; 2016, 28; 37-52
1429-7426
2083-4535
Pojawia się w:: Journal of Water and Land Development
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Estimation of the depth of penetration in a plunging hollow jet using artificial intelligence techniques
Autorzy:: Bodana, D.
Tiwari, N. M.
Ranjan, S.
Ghanekar, U.
Powiązania:: https://bibliotekanauki.pl/articles/1818515.pdf
Data publikacji:: 2020
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: depth of penetration
machine learning model
classical models
plunging hollow jets
głębokość penetracji
model uczenia maszynowego
modele klasyczne
Opis:: Purpose: Experimental investigations assessment and comparison of different classical models and machine learning models employed with Gaussian process regression (GPR) and artificial neural network (ANN) in the estimation of the depth of penetration (Hp) of plunging hollow jets. Design/methodology/approach: In this analysis, a set of data of 72 observations is derived from laboratory tests of plunging hollow jets which impinges into the water pool of tank. The jets parameters like jet length, discharge per unit water depth and volumetric oxygen transfer coefficient (Kla20) are varied corresponding to the depth of penetration (Hp) are estimated. The digital image processing techniques is used to estimate the depth of penetration. The Multiple nonlinear regression is used to establish an empirical relation representing the depth of penetration in terms of jet parameters of the plunging hollow jets which is further compared with the classical equations used in the previous research. The efficiency of MNLR and classical models is compared with the machine learning models (ANN and GPR). Models generated from the training data set (48 observations) are validated on the testing data set (24 observations) for the efficiency comparison. Sensitivity assessment is carried out to evaluate the impact of jet variables on the depth of penetration of the plunging hollow jet. Findings: The experimental performance of machine learning models is far better than classical models however, MNLR for predicting the depth of penetration of the hollow jets. Jet length is the most influential jet variable which affects the Hp. Research limitations/implications: The outcomes of the models efficiency are based on actual laboratory conditions and the evaluation capability of the regression models may vary beyond the availability of the existing data range. Practical implications: The depth of penetration of plunging hollow jets can be used in the industries as well as in environmental situations like pouring and filling containers with liquids (e.g. molten glass, molten plastics, molten metals, paints etc.), chemical and floatation process, wastewater treatment processes and gas absorption in gas liquid reactors. Originality/value: The comprehensive analyses of the depth of penetration through the plunging hollow jet using machine learning and classical models is carried out in this study. In past research, researchers were used the predictive modelling techniques to simulate the depth of penetration for the plunging solid jets only whereas this research simulate the depth of penetration for the plunging hollow jets with different jet variables.
Źródło:: Archives of Materials Science and Engineering; 2020, 103, 2; 49--61
1897-2764
Pojawia się w:: Archives of Materials Science and Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Instructions for the preparation of a numerical investigation on crack parameters of cantilever beam using FEA
Autorzy:: Ansari, M. A.
Tiwari, V. K.
Powiązania:: https://bibliotekanauki.pl/articles/2055757.pdf
Data publikacji:: 2021
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: ANSYS
vibration
cantilever beam
wibracja
belka wspornikowa
Opis:: Purpose: The operation of engineering structures may cause various type of damages like cracks, alterations. Such kind of defects can lead to change in vibration characteristics of cantilever beam. The superposition of frequency causes resonance leading to amplitude built up and failure of beam. The current research investigates the effect of crack dimensional parameters on vibrational characteristics of cantilever beam. Design/methodology/approach: The CAD design and FE simulation studies are conducted in ANSYS 20 simulation package. The natural frequencies, mode shapes and response surface plots are generated, and comparative studies are performed. The effect of crack dimensional parameters is then investigated using Taguchi Design of Experiments. The statistical method of central composite design (CCD) scheme in Response Surface Optimization is used to generated various design points based on variation of crack width and crack depth. Findings: The research findings have shown that crack depth or crack height have significant effect on magnitude of deformation and natural frequency. The deformation is minimum at 0.009 m crack height and reaches maximum value at 0.011 m crack height. Research limitations/implications: The crack induced in the cantilever beam needs to be repaired properly in order to avoid crack propagation due to resonance. The present study enabled to determine frequencies of external excitation which should be avoided. The limitation of current research is the type of crack studied which is transverse type. The effect of longitudinal cracks on vibration characteristics is not investigated. Practical implications: The study on mass participation factor has shown maximum value for torsional frequency which signifies that any external excitation along this direction should be avoided which could cause resonance and lead to amplitude build up. Originality/value: The beams are used in bridge girders and other civil structures which are continuously exposed to moist climate. The moisture present in the air causes corrosion which initiates crack. This crack propagates and alters the natural frequency of beam.
Źródło:: Journal of Achievements in Materials and Manufacturing Engineering; 2021, 109, 1; 5--10
1734-8412
Pojawia się w:: Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Kernel function based regression approaches for estimating the oxygen transfer performance of plunging hollow jet aerator
Autorzy:: Kumar, M.
Tiwari, N. K.
Ranjan, S.
Powiązania:: https://bibliotekanauki.pl/articles/368684.pdf
Data publikacji:: 2019
Wydawca:: Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:: volumetric oxygen transfer coefficient
multiple nonlinear regression
Gaussian process regression
support vector regression
współczynnik wnikania tlenu
regresja nieliniowa
proces gaussowski
regresja wektora wsparcia
Opis:: Purpose: To evaluate the capability of various kernels employed with support vector regression (SVR) and Gaussian process regression (GPR) techniques in estimating the volumetric oxygen transfer coefficient of plunging hollow jets. Design/methodology/approach: In this study, a data set of 81 observations is acquired from laboratory experiments of hollow jets plunging on the surface of water in the tank. The jet variables: jet velocity, jet thickness, jet length, and water depth are varied accordingly and the values of volumetric oxygen transfer coefficient is computed. An empirical relationship expressing the oxygenation performance of plunging hollow jet aerator in terms of jet variables is formulated using multiple nonlinear regression. The performance of this nonlinear relationship is compared with various kernel function based SVR and GPR models. Models developed with the training data set (51 observations) are checked on testing data set (24 observations) for performance comparison. Sensitivity analysis is carried out to examine the influence of jet variables in effecting the oxygen transfer capabilities of plunging hollow jet aerator. Findings: The overall comparison of kernels yielded good estimation performance of Radial Basis Function kernel (RBF) and Pearson VII Function kernel (PUK) using the SVR technique which is followed by nonlinear regression, and other kernel function based regression models. Research limitations/implications: The results of the study pertaining to the performance of kernels are based on the current experimental conditions and the estimation potential of the regression models may fluctuate beyond the selection of current data range due to datadependant learning of the soft computing models. Practical implications: Volumetric oxygen transfer coefficient of plunging hollow jets can be predicted precisely using SVR model by employing RBF as kernel function as compared to empirical correlation and other kernel function based regression models. Originality/value: The comparative analysis of kernel functions is conducted in this study. In previous studies, the predictive modelling approaches are implemented in simulating the aeration properties of cylindrical solid jets only, while this paper simulates the volumetric oxygen transfer coefficient of diverging hollow jets with the jet variables by utilizing polynomial, normalized polynomial, PUK, and RBF kernels in SVR and GPR.
Źródło:: Journal of Achievements in Materials and Manufacturing Engineering; 2019, 95, 2; 74-84
1734-8412
Pojawia się w:: Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Effect of periphery fixity on ballistic limit of thin aluminum plate subjected to blunt and ogival projectile impact
Autorzy:: Tiwari, G.
Iqbal, M. A.
Gupta, P. K.
Powiązania:: https://bibliotekanauki.pl/articles/955195.pdf
Data publikacji:: 2014
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:: symulacja numeryczna
metoda elementów skończonych
aluminium
periphery fixity
blunt nosed projectile
ABAQUS
Opis:: Three-dimensional numerical simulations were carried out with the ABAQUS/explicit finite element code to study the influence of target boundary conditions on its ballistic limit. 1mm thick 1100-H12 aluminum target of 255 mm span diameter was hit by 19 mm diameter and 50.8 mm length blunt nosed projectile. The mass of the projectile was kept as 52.5 gm. The boundary condition effects on the ballistic limit were investigated by varying the target periphery boundary condition as fully clamped and partially clamped target (75%, 50% and 25%) subjected to projectile impact. The energy absorption and ballistic limit of the target was found to be significantly affected by the boundary conditions. Some of the finite element analysis results were compared with experimental and numerical results reported in international literature and a good agreement between the two was found.
Źródło:: International Journal of Applied Mechanics and Engineering; 2014, 19, 2; 379-395
1734-4492
2353-9003
Pojawia się w:: International Journal of Applied Mechanics and Engineering
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The effect of additional additives on the axillary shoot micropropagation of medicinal plant Aegle marmelos (L.) Corrêa
Autorzy:: Mandal, Shubhjeet
Parsai, Abhishek
Tiwari, Piyush Kumar
Nataraj, M.
Powiązania:: https://bibliotekanauki.pl/articles/1031277.pdf
Data publikacji:: 2021
Wydawca:: Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:: Additives
Aegle marmelos
Amino Acids
Axillary Shoot Culture
Micropopgation
PGR
Tissue Culture
Opis:: India is an immense medicinal plant repository, used in traditional medical treatments. The use of herbal medicine is growing day by day due to toxicity and allopathic drug effects. About 90 percent of the phytochemicals marketed come from wild resources and over 120 major phytochemistry come from plants. Aegle marmelos leaves contained π-sitosterol, aegelin, lupeol, rutin, marmesinine, flavone, glycoside, Oisopentenyl halfordiol, marmeline, and phenylethyl cinnamides. The additional growth promoters show its effect on tissue culture of plant.
Źródło:: World News of Natural Sciences; 2021, 34; 54-71
2543-5426
Pojawia się w:: World News of Natural Sciences
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Memory response on generalized thermoelastic medium in context of dual phase lag thermoelasticity with non-local effect
Autorzy:: Tiwari, R.
Saeed, A. M.
Kumar, R.
Kumar, A.
Singhal, A.
Powiązania:: https://bibliotekanauki.pl/articles/38694222.pdf
Data publikacji:: 2022
Wydawca:: Instytut Podstawowych Problemów Techniki PAN
Tematy:: memory dependent derivative
time-delay
kernel function
non-local
continuum theory
dual phase lags
Opis:: Theory of non-local continuum is contemporary appraised and is found to be supplementary coherent to capture the impacts of each and every point of the material at its single point. The conviction of memory dependent derivative is also newly appraised and is observed to be more intuitionistic for predicting the realistic character of the real-world obstacles. Attractiveness of the belief of a memory dependent derivative lies in its unique properties such as its significant constituents – a kernel function and time-delay are freely selected according to the requirement of a problem. The present study comprises a new meticulous thermoelastic heat conduction model for the homogeneous, isotropic, thermoelastic half space medium concerning memory effects and non-local effects. Governing equations are constructed on the basis of the newly appraised non-local generalized theory of thermoelasticity with two phase lags in the frame of a memory dependent derivative. Exact analytical solutions of the physical fields such as dimensionless temperature, displacement as well as thermal stress are evaluated by using a suitable technique of the Laplace transform. Quantitative results are determined in a time-domain for different values of time by taking the numerical inversion of the Laplace transform. Noteworthy role of the constituents of the memory dependent derivative such as kernel function as well as time-delay factor has been scrutinized on the crucial field variables of the medium through computational outcomes. Moreover, the impact of non-local parameter is examined on the variations of field quantities through the quantitative results.
Źródło:: Archives of Mechanics; 2022, 74, 2-3; 69-88
0373-2029
Pojawia się w:: Archives of Mechanics
Dostawca treści:: Biblioteka Nauki

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