Method For Determination Of Parameters Research Articles

On convergence of iterative method for determination of weibull parameters by maximum likelihood method

The Weibull distribution is frequently used for the assessment of wind energy potential and modeling of wind speed data. The parameters of Weibull distribution are determined by a number of methods; Maximum Likelihood Methods is one of them. The values of scale and shape parameters of Weibull distribution are found by the help of Maximum Likelihood function. Two different techniques are used to find the parameters. One is known as iterative method, in which a start value of ‘k’ is set and iterations are terminated when given criterion is reached. The second method is Newton Raphson method of finding roots. We report here a problem of non-convergence of iterative method. We suggest the Newton Raphson method as the best choice for finding the value of ‘k’ through Maximum Likelihood Method.

Concise Robust Control of Marine Engine Speed Based on Backstepping and Its Fuzzy Comprehension

In this paper, a concise robust control law based on Backstepping for marine engine speed regulation is presented with the uniform asymptotic stability of the closed‐loop system proved by Lyapunov synthesis, and the control parameters have obvious physical meaning. Furthermore, parameter determination method is given by virtue of closed‐loop gain shaping algorithm. To overcome the perturbation due to load or interference change, variable universe fuzzy inference is introduced to optimize the control system on‐line. Compared with the existing research literature, the design method and performance of the controller are more in line with the ocean engineering practice. The results of the simulations of the proposed controller are presented and compared.

Method for determination of resists parameters for photonic - integrated circuits e-beam lithography on silicon nitride platform

In the work the thicknesses of the e-beam resists ZEP 520A and ma-N 2400 by using non-destructive method were measured, as well as recipe for the high ratio between the Si3N4 and the resists etching rate was determined. The work has a practical application for e-beam lithography of photonic-integrated circuits and nanophotonics devices based on silicon nitride platform.

Gas emission through coal particles using instantaneous gas diffusion coefficients: experimental and modelling study

Similarity theory and the second law of diffusion were used to develop a diffusion model to accurately characterise the behaviour of gas emissions from coal particles. A method for calculating instantaneous diffusion coefficients, D(t), was established. These were incorporated into the diffusion equation and its analytical solution obtained via separation of variables. The results indicated that changes of D(t) as a function of time were described by a power function. The model accurately characterises the entire process of gas emission from coal particles and reflects the complexities of pore size. It provides a new calculation method and theoretical reference for determination and prediction of parameters for gas emission from coal seams. [Received: August 10, 2017; Accepted: January 9, 2018]

Проверка эффективности метода определения параметров циклического заводнения на основе анализа КВД

Проверка эффективности метода определения параметров циклического заводнения на основе анализа КВД

Методика определения электрических параметров с учетом волновой теории передачи электрической энергии

Методика определения электрических параметров с учетом волновой теории передачи электрической энергии

Про один метод визначення параметрів ядер спадковості нелінійно в’язкопржних матеріалів за умов складного напруженого стану

The deformation of viscoelastic medium given by means of constitutive equations of the hereditary type. These equations establish the relationship between the components of strain tensor, the components of stress tensor and the integral time operator, and contain the set of function and coefficients that are determined from the basic experiments. А method of the heredity kernel parameters determination of nonlinear viscoelastic materials is developed. As the visco-elastic model, the constitutive equations of the hereditary type are chosen in which the relationship between the components of the strain tensor and the stress tensor is given based on the hypothesis of the deviators proportionality. The nonlinearity of the viscoelastic properties is given by the equations of Ratotnov’s type. The method is based on the relations between the creep kernels under complex stress state and the creep kernels under one-dimensional stress state. The method verified experimentally for the problems of determination of creep deformations under combined loading applied to the thin-walled tubular elements made of polyethylene of high density.

A dynamic modelling method for dynamic wireless charging system of electric vehicles based on dual LCL non-resonant compensation

This paper starts with a mutual inductance coupling model and takes compensation structure of 'series connection-series connection' as an example to respectively deduce the mathematical expressions for system output power and efficiency when traditional resonant compensation strategy and non-resonant compensation strategy are adopted, so as to compare the advantages and disadvantages of the two strategies from the aspect of influence of coupling coefficient change on the output power and efficiency. Then, to cope with the drawbacks of non-resonant compensation strategy, a dynamic modelling method for electromobile's dynamic wireless charging system based on dual-LCL non-resonant compensation is proposed to analyse the structure's function of improving the system's power transmission capacity and determination method of different component parameters from the perspectives of circuit equivalence and impedance conversion. Models are built for rectifier and filter circuit, DC-DC circuit and loading battery pack for receiving terminal, and the characteristics of each link are expressed mathematically.

Parameter determination method of three-dimensional vibration analysis model for railway vehicle

The elastic vibrations of the carbody tend to have influence on riding comfort in recent railway vehicles. For studying methods to reduce these vibrations, numerical analysis models are required. The authors proposed a simple analytical model that can express several three-dimensional elastic vibration modes of a carbody. Along with the modelling technique, determining the parameters used in the analysis models (called “model parameters” in this work) is also important. This study proposes a method to determine model parameters using particle swarm optimization (PSO), which is one of the optimization techniques, together with measured data. In this method, the frequency response functions (FRFs) at the several points on the vehicle were used to evaluate fitness between calculated and measured results, and the parameters that minimize the difference between them are decided. In order to verify the validity of the proposed method, excitation tests using Shinkansen type test vehicle were performed. As the results, good agreements between measured and calculated results were observed and the validity of the proposed method was confirmed.

ВЕТЕРИНАРНО-САНИТАРНАЯ ОЦЕНКА КАЧЕСТВА И БЕЗОПАСНОСТИ ТОВАРНОЙ СТЕРЛЯДИ, ВЫРАЩЕННОЙ С ИСПОЛЬЗОВАНИЕМ РЕЦИРКУЛЯЦИОННЫХ ТЕХНОЛОГИЙ

The article studies the safety of sterlet grown in recirculating aquaculture systems. The research was carried out in the research and training laboratory on reproduction and cultivation of sturgeon species of the Department of private animal husbandry, livestock and aquaculture technology of Ulyanovsk State Agrarian University named after P. A. Stolypin and Simbirsk Veterinary Reference Center in Ulyanovsk. The material for the study was chosen sterlet grown in recirculating aquaculture systems. In the recirculating aquaculture system food components and metabolites accumulate, which may affect fish health and quality and safety of fish meat. In the course of studies it has been found that hydrochemical parameters of water taken from the breeding tanks comply with the standards: ammonia content as the main indicator affecting the growth and development of fish did not exceed 0.05 mg/dm3. This is due to compliance with fish stocking density, optimum temperature (18-22°C) and pH level (7.3). The content of sulfates was also within the norm -52.78 mg/dm3. Mass fraction of chlorides was 14.82 mg/dm3 and of nitrites - 0.052 mg/dm3, which is 20 and 50 times lower than the standard values. The fish was studied for organoleptic, microbiological parameters, as well as for the content of toxic elements. Organoleptic characteristics (appearance, fish condition, smell, color of eyes and gills) fully meet the requirements of GOST 7631-2008 “Fish, non-fish objects and their products. Methods for determination of organoleptic and physical parameters”; such toxic elements as cadmium (Cd), arsenic (As), mercury (Hg) and lead (Pb) were detected in fish samples, but their content was negligible and did not exceed the maximum permissible concentrations. The presence of genetically modified organisms, pathogens, BGB (coliforms), Listeria, nematodes were not detected. According to the study results, sterlet grown in the recirculating aquaculture conditions of the research laboratory for reproduction and breeding of sturgeon species of the Department of private zootechny, technology of animal husbandry and aquaculture of Ulyanovsk State Agrarian University can be considered completely safe in terms of microbiological, parasitological and chemical indicators.

Suspension- and powder-based derivation of Hansen dispersibility parameters for zinc oxide quantum dots

For most particle-based applications, formulation in the liquid phase is a decisive step, and thus, particle interactions and stability in liquid media are of major importance. The concept of Hansen solubility parameters (HSP) was initially invented to describe the interactions of (polymer) molecules and their solubility in different liquids and is increasingly being used in particle technology to describe dispersibility. Because dispersions are not thermodynamically stable, the term Hansen dispersibility parameters (HDP) is used instead of HSP (Süß, Sobisch, Peukert, Lerche, & Segets, 2018). Herein, we extend a previously developed standardized and non-subjective method for determination of Hansen parameters based on analytical centrifugation to the important class of quantum materials. As a technically relevant model system, zinc oxide quantum dots (QDs) were used to transfer our methodology to nanoparticles (NPs) with sizes below 10nm. The results obtained using the standard procedure starting from a dried powder were compared with those obtained through redispersion from the wet sediment produced during the typical washing procedure of QDs, and drying was observed to play an important role. In conclusion, our study reveals the high potential of HDP for quantifying the interfacial properties of NPs as well as their link to dispersibility.

Hydrogeological Parameter Determination in the Southern Catchments of Taiwan by Flow Recession Method

The understanding of hydrogeological characteristics and groundwater flow processes in aquifers is crucial for the determination of sustainable groundwater resource development as well as hydrological management and planning. In the past, information on hydrogeological characteristics was mainly acquired through point field measurement such as borehole geophysical techniques and field aquifer hydraulic testing. However, in view of the cost limitations and scale applicability of these methods, low-flow recession analysis techniques that utilize streamflow data can be used as alternative low-cost methods to reversely back-calculate hydrogeological parameters based on the hydrological processes by which groundwater from aquifers is naturally discharged to rivers. We chose Southern Taiwan as the study area for the estimation of the recession index (K), which is representative of catchment discharge behavior during both the dry and wet seasons, to determine seasonal differences in the aquifer flow regime and to estimate the following three hydrogeological parameters: hydraulic conductivity (k), specific yield (Sy), and transmissivity (T). Based on the field test reports of the locations of groundwater observational wells on the Chianan and Pingtung plains, the study area was divided into the Chianan sub-area (Zengwun, Yanshui, and Erren river basins) and the Kaoping sub-area (Kaoping, Donggang, and Linbian river basins). The estimation results of the present study were compared to the field test results. The results showed significant differences in the recession index K between the dry and wet seasons. Slight differences between the estimated hydrogeological parameters and the field test results were also observed for the two sub-areas because of differences in scale. Furthermore, regional differences in the estimation results were found to be consistent with the distribution of geological structures, which indicates a high degree of feasibility in the application of flow recession methods for catchment-scale hydrogeological parameter determination.

Method for determination of technological mode parameters of electron-beam welding based on the application of optimality criterion with the view on the weld pool uniform heating

The paper presents the results of mathematical modelling of temperature fields when the AMG-6 alloy is heated with energy sources equivalent to an electron beam in electron-beam welding. The evaluation of the results was performed using the criterion of optimality proposed by the authors. Used as a functional for calculations was the normalized standard deviation of the temperature from heating by a complex heat source consisting of mobile instantaneous point and linear energy sources. Proposed in this work are both an algorithm for finding solutions using an optimality criterion and the results of calculations for plates with thicknesses of 0.12cm and 1.2cm from the AMG-6 material, which were compared with experiments carried out under laboratory conditions.

METHOD OF DETERMINING THE PARAMETERS OF AN EQUIVALENT ASYNCHRONOUS ELECTRIC MOTOR IN REAL TIME

A calculation of the parameters of the equivalent asynchronous electric machine allows introducing the automated calculation of the static and dynamic stability of an electrical supply system in an industrial enterprise for any combination of different electric motors. It also ensures the electromagnetic compatibility in a network by means of calculations of nonsinusoidal mode in the network with proposed sources of higher harmonics. The research purpose is a method for accurate determination of the equivalent asynchronous machine parameters for the load node consisting of several groups of asynchronous electric motors of the same type. An algorithm block diagram for calculating the initial data is developed. The input data is the number of groups of the same motor type, the number of machines in each group, and a vector of the engine power ratings. The polling of the counters of each engine in all groups is performed through the use of an embedded cycle. A fragment of a substation one-line scheme which feeds an electrical industrial enterprise water circuit is given: three 800 kW asynchronous machines for each pump, three 400 kW asynchronous machines and three 250 kW asynchronous machines. The calculation results for the given example of the scheme are executed and presented in the table. The data obtained show that the actual parameters of the equivalent machine in a 6 kV load node are significantly different from the averaged data. The typical difference between the results obtained by the proposed method and the available methods is 5%, and the maximum reaches 30%. Therefore, it is expedient to use accurate data when performing calculations.

Bacteriophage production processes.

High quantities of bacteriophages are currently used in the food industry and agriculture. However, growing antibiotic resistance of bacteria has recently awakened the interest to use bacteriophages for the treatment of bacterial infections in humans indicating that even higher quantities will be required in the future. High demand combined with a wide range of applications requires also efficient bacteriophage production processes operating at low production costs and with high productivity. To achieve this goal, different approaches were introduced and extensive studies of various parameters affecting bacteriophage formation were investigated. In this mini-review, we provide a short overview about different operation modes of bacteriophage production such as batch, semi-continuous and especially continuous with the pros and cons of each. We present factors affecting bacterial physiological state, its effect on phage formation and provide a description of methods for determination of bacteriophage growth parameters, through which bacteriophage formation is obtained. Understanding of described phenomena and inclusion of potential occurrence of mutations and selection in continuous systems enables evaluation of continuous process productivity and its optimization.

Geospatial analysis of surface hydrological parameters for Kyushu Island, Japan

Defining the surface hydrological parameters represents a crucial factor for the sustainable development purposes. In areas with heavy precipitation and rugged topography, these parameters control the occurrence of some natural hazards, from which the flash flood gets the most attention. Traditional methods for the assessment of the surface hydrological parameters are costly, time-consuming and provide information for limited geographic extent. On the other hand, remotely sensed data provide a cost-effective, rapid and wide aerial coverage with adequate accuracy. Geospatial analysis of these remotely sensed data provides a suitable and effective method for the reconnaissance determination of the surface hydrological parameters. In this work, digital elevation models, Landsat 8 satellite images as well as digital maps of soil and land use for Kyushu Island were acquired and analyzed using geographic information system. Surface hydrological parameters were determined in terms of watershed boundaries, soil moisture, initial abstraction as well as flash flood potentiality. Results of this research show a great correlation with historical flash flood events that occurred in the island. The northern parts of the island are subjected to the threat of flash floods. A follow-up is recommended in some areas on the island. As a conclusion, the geospatial analysis performs an accurate reconnaissance method for hydrological analysis at regional scale, which in turn guides the detailed field observation saving time and cost.

Method for Parameter Determination of Ceramic Products Compression Using the Mounting for Curves Readout

There are given technological factors of pressing of products from ceramic powders. The pressing process is represented as a functional dependence with a set of variables. Four stages of ceramic powders pressing have been found. The method on determination of the pressing parameters of ceramic products using the mounting for curves readout has been shown. Sediment of press powders from clay raw material is determined at different humidity and pressing pressure. The dependence of the physical and mechanical properties of ceramic samples on the humidity content of clay powder and the pressure of raw pressing is established. Compacting pressure values have been found by compression curve when plastic deformation ends and elastic deformations of powder grains start, which corresponds to a translation from the second to the third stage of the pressing process. Areas of rapid deceleration of sagging are in line with the point of the tangent to this curve in the translation from the third to the fourth compression stage have been found. The optimal values of semidry pressing of a ceramic brick have been defined.

Accuracy of electrocardiographic imaging using the method of fundamental solutions

Solving the inverse problem of electrocardiology via the Method of Fundamental Solutions has been proposed previously. The advantage of this approach is that it is a meshless method, so it is far easier to implement numerically than many other approaches. However, determining the heart surface potential distribution is still an ill-posed problem and thus requires some form of Tikhonov regularisation to obtain the required distributions.In this study, several methods for determining an “optimal” regularisation parameter are compared in the context of solving the inverse problem of electrocardiology via the Method of Fundamental Solutions. It is found that the Robust Generalised Cross-Validation method most often yields epicardial potential distributions with the least relative error when compared to the input distribution. The study also compares the inverse solutions obtained with the Method of Fundamental Solutions with those obtained in a previous study using the boundary element method. It is found that choosing the best solution methodology and regularisation parameter determination method depends on the particular scenario being considered.

FOG De-Noising Algorithm Based on Augmented Nonlinear Differentiator and Singular Spectrum Analysis

A novel algorithm based on singular spectrum analysis (SSA) and augmented nonlinear differentiator (AND) for extracting the useful signal from a noisy measurement of fiber optic gyroscope (FOG) is proposed in this paper. As a novel type of tracking differentiator, augmented nonlinear differentiator (AND) has the advantages of dynamical performance and noise-attenuation ability. However, there is a contradiction in AND, i.e., selecting a larger acceleration factor may cause faster convergence but bad random noise reduction, whereas selecting a smaller acceleration factor may lead to signal delay but effective random noise reduction. To overcome the contradiction of AND, multi-scale transformation is introduced. Firstly, the noisy signal is decomposed into components by SSA, and the correlation coefficients between each component and original signal are calculated, then the component with biggest correlation coefficient is reserved and other components are filtered by AND with designed selection criterion of acceleration factor, finally the de-noising result is obtained after reconstruction process. There are mainly two prominent advantages of the proposed SSA-AND algorithm: (i) Compared to traditional tracking differentiators, better de-noising ability can be achieved without signal delay; and (ii) compared to other widely used hybrid de-noising methods based on multi-scale transformation, a parameter determination method is given based on the correlation coefficient of each decomposed component, which improves the reliability of the proposed algorithm.

Johnson–Holmquist-II(JH-2) Constitutive Model for Rock Materials: Parameter Determination and Application in Tunnel Smooth Blasting

The Johnson–Holmquist-II(JH-2) model is introduced as the constitutive model for rock materials in tunnel smooth blasting. However, complicated and/or high-cost experiments need to be carried out to obtain the parameters of the JH-2 constitutive model. This study chooses Barre granite as an example to propose a quick and convenient determination method for the parameters of the JH-2 model using a series of computational and extrapolated methods. The validity of the parameters is verified via comparing the results of 3D numerical simulations with laboratory blast-loading experiments. Subsequently, the verified parameter determination method, together with the JH-2 damage constitutive model, is applied in the numerical simulation of smooth blasting in Zigaojian tunnel, Hangzhou–Huangshan high-speed railway. The overbreak/underbreak induced by rock blasting and joints/discontinuities is well estimated through comparing the damage contours resulting from the numerical study with the tunnel profiles measured from the tunnel site. The peak particle velocities (PPVs) of the near field are extracted to estimate the damage scope and damage degree for the surrounding rock mass of the tunnel on the basis of PPV damage criteria. This method can be used in the excavation of rock tunnels subjected to large strains, high strain rates, and high pressures, thereby reducing safety risk and economic losses.