scholarly journals ANN-MATOPT hybrid algorithm: determination of kinetic and non-kinetic parameters in different reaction mechanisms

2021 ◽  
Author(s):  
M. M. Canedo Alonso ◽  
Jaime González Cuadra ◽  
J. L. González-Hernández
Keyword(s):  
Reaction Mechanisms ◽  
Hybrid Algorithm ◽  
Synthetic Data ◽  
Number Of Solutions ◽  
Deterministic Analysis ◽  
Different Types ◽  
Determination Of Parameters ◽  
Parameter Values ◽  
Complete Process

AbstractIn this work we have applied the computational methodology based on Artificial Neural Networks (ANN) to the kinetic study of distinct reaction mechanisms to determine different types of parameters. Moreover, the problems of ambiguity or equivalence are analyzed in the set of parameters to determine in different kinetic systems when these parameters are from different natures. The ambiguity in the set of parameters show the possibility of existence of two possible set of parameter values that fit the experimental data. The deterministic analysis is applied to know beforehand if this problem occurs when rate constants of the different stages of the mechanism and the molar absorption coefficients of the species participating in the reaction are obtained together. Through the deterministic analysis we will analyze if a system is identifiable (unique solution or finite number of solutions) or if it is non-identifiable if it possesses infinite solutions. The determination of parameters of different nature can also present problems due to the different magnitude order, so we must analyze in each case the necessity to apply a second method to improve the values obtained through ANN. If necessary, an optimization mathematical method for improving the values of the parameters obtained with ANN will be used. The complete process, ANN and mathematical optimizations constitutes a hybrid algorithm ANN-MATOPT. The procedure will be applied first for the treatment of synthetic data with the purpose of checking the applicability of the method and after, it will be used in the case of experimental kinetic data.

scholarly journals Easy-hard phase transition in parameter estimation for optical waveguides

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gunnar Claussen ◽  
Alexander K. Hartmann
Keyword(s):  
Phase Transition ◽  
Optical Waveguides ◽  
Energy Landscape ◽  
Global Optimum ◽  
Local Minima ◽  
Different Types ◽  
Two Phases ◽  
Parameter Values ◽  
Monochromatic Illumination

Abstract The determination of the parameters of cylindrical optical waveguides, e.g. the diameters $$\vec {d}=(d_1,\ldots ,d_r)$$ d → = ( d 1 , … , d r ) of r layers of (semi-) transparent optical fibres, can be executed by inverse evaluation of the scattering intensities that emerge under monochromatic illumination. The inverse problem can be solved by optimising the mismatch $$R(\vec {d})$$ R ( d → ) between the measured and simulated scattering patterns. The global optimum corresponds to the correct parameter values. The mismatch $$R(\vec {d})$$ R ( d → ) can be seen as an energy landscape as a function of the diameters. In this work, we study the structure of the energy landscape for different values of the complex refractive indices $$\vec {n}$$ n → , for $$r=1$$ r = 1 and $$r=2$$ r = 2 layers. We find that for both values of r, depending on the values of $$\vec {n}$$ n → , two very different types of energy landscapes exist, respectively. One type is dominated by one global minimum and the other type exhibits a multitude of local minima. From an algorithmic viewpoint, this corresponds to easy and hard phases, respectively. Our results indicate that the two phases are separated by sharp phase-transition lines and that the shape of these lines can be described by one “critical” exponent b, which depends slightly on r. Interestingly, the same exponent also describes the dependence of the number of local minima on the diameters. Thus, our findings are comparable to previous theoretical studies on easy-hard transitions in basic combinatorial optimisation or decision problems like Travelling Salesperson and Satisfiability. To our knowledge our results are the first indicating the existence of easy-hard transitions for a real-world optimisation problem of technological relevance.

Modelling of a recirculating granular medium filter's processes

2002 ◽  
Vol 45 (12) ◽  
pp. 241-250
Author(s):  
C. Boutin ◽  
R. Parouty ◽  
C. Ménoret ◽  
A. Liénard ◽  
F. Brissaud
Keyword(s):  
Food Processing ◽  
Full Scale ◽  
Hydrodynamic Characteristics ◽  
Small Farm ◽  
High Concentration ◽  
Treatment Techniques ◽  
Different Types ◽  
Hydraulic Load ◽  
Parameter Values

The effluents of French small farm factories will soon be submitted to regulation. Only a few treatment techniques are available to deal with these kind of effluent (high concentration and small daily volumes). To allow the treatment, in the particular economic context of small food processing industries, Cemagref is trying to adapt a treatment based on attached growth cultures on fine media, a system known to be easy to operate and relatively inexpensive. A model, based on four sub-models (hydrodynamic characteristics, oxygen transport, solute transport in the mobile and immobile phases and bacterial evolution) describes this process. Based on wastewater concentration, hydraulic load, applied organic loads, feeding / rest cycles and recycling phases number, this model predicts:•eliminated organic loads and the discharge concentration as a function of time,•oxygen and biomass contents as a function of time and depth. The determination of the model's parameters is based on a comparison between simulations and performances achieved on experimental columns. This model would be helpful in sizing full-scale filters treating different types of agro-food wastewater. The aim of this article is to present the model's structure, to give all parameter values and to compare the simulations with the results obtained on pilot and full scale plants.

scholarly journals Gain Error end DNL for Testing ADCs: Optimization in Time Domain

2020 ◽  
Vol 9 (3) ◽  
pp. 891-894
Keyword(s):  
Digital Form ◽  
Analog To Digital ◽  
Test Conditions ◽  
Gain Error ◽  
Transition Level ◽  
Determination Of Parameters ◽  
Parameter Values ◽  
Estimation Of Variance

Optimization in ADC is an important component which predicts overall accuracy of a system using it. Signals are in real time nature and it is necessary to convert these signals in digital form to interpret with digital form of signals and microcomputer based systems. ADC is used to carry out these conversions process from analog to digital. Determination of parameters of an ADC such as DNL, INL, SNR and ENOB are necessary for complete dynamic analysis and characterization of ADC. In frequently, application prerequisite input to an Analog to digital converter is time varying which requires determination of its parameters at corresponding frequency and different test conditions In order to test an ADC, it is necessary to first determine its code transition levels. Further Gain error, DNL are estimated using code transition level based on histogram technique. If there is an code transition level error introduced then effect of this error leads to error in estimate of gain, offset, DNL and ENOB. Further estimation of variance in different parameter values is analyzed in the proposed work.

XX.—The Square Roots of a Linear Vector Function

1918 ◽  
Vol 37 ◽  
pp. 350-355
Author(s):  
Frank L. Hitchcock
Keyword(s):  
Point Of View ◽  
Number Of Solutions ◽  
Square Roots ◽  
Linear Vector ◽  
Different Types ◽  
Rotational Parts ◽  
Image Position ◽  
Homogeneous Strain ◽  
Elegant Solution

The equation in linear vector functionswas proposed by Tait, and an elegant solution was obtained by him which does not require a determination of the axes of ω. He showed that upon this equation depends the separation of the pure and the rotational parts of a homogeneous strain. The problem appears to be interesting also from the point of view of algebraic analysis. The number and character of the solutions is more varied, given different types of the function ω, than we might at first suppose. In fact there are two forms which may be assigned to M such that the equation does not permit of solution. Otherwise the number of solutions.

scholarly journals The application of taḥawwul (transformation) process for determination of vinegar status in the Malaysia market

Food Research ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 896-905
Author(s):  
I. Harahap ◽  
A.S.M. Shukri ◽  
M.A. Jamaludin ◽  
N. Nawawi ◽  
R. Alias ◽  
...  
Keyword(s):  
Gas Chromatography ◽  
Transformation Process ◽  
Ionization Detector ◽  
Flame Ionization ◽  
Flight Mass Spectrometry ◽  
Different Types ◽  
The Status ◽  
Complete Process ◽  
Acetic Acids

Taḥawwul is a changing process of a form to another form thus could affect the status of a particular ḥukm especially in vinegar products. Vinegar which produced before the taḥawwul ṣaḥīḥ can be considered as low-quality vinegar and is classified as fasīd vinegar (ḥarām) due to the presences of alcohol which is prohibited in Islam. Therefore, in this study, twenty-five different types of vinegar in Malaysian market were tested using Gas Chromatography attached with Flame Ionization Detector (HS-GC-FID) with Head Space Analyzer (HS-10) and Gas Chromatography (GC) with time of flight mass spectrometry (TOF-MS) to find out the contents of alcohol and acetic acids present in the said vinegar products. The results showed that majority of the sample were ḥalāl. However, there were two types of vinegar that were not considered ḥalāl because these products did not go through a complete process of (taḥawwul ṣaḥīḥ).

Determination of parameters of short circuit of power transformer by means of mathematical modeling

2017 ◽  
Vol 26 (102) ◽  
pp. 110-119
Author(s):  
D. S. Yarymbash, ◽  
◽  
S. T. Yarymbash, ◽  
T. E. Divchuk, ◽  
D. A. Litvinov
Keyword(s):  
Mathematical Modeling ◽  
Power Transformer ◽  
Short Circuit ◽  
Determination Of Parameters
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