Method For Calculation Of Parameters Research Articles

Intermediate Observer-Based Robust Distributed Fault Estimation for Nonlinear Multiagent Systems With Directed Graphs

This article focuses on the problem of robust distributed fault estimation for nonlinear multiagent systems with actuator faults and sensor faults. The communication topology of the multiagent systems is assumed to be directed. A novel intermediate observer design method is proposed to estimate the system states, actuator faults, and sensor faults. For the observer constructed in one agent, the output estimation errors of itself and its neighbors are considered, simultaneously. The observer matching condition is not needed in the observer design process. Based on Schur decomposition, the observer parameter calculation method is presented in terms of solution to one linear matrix inequality, which is with the same order as it is for the single agent system. Thus, the calculated amount remains unchanged even when the number of agents increases, since the inequality dimension is independent of the agent number. At last, simulation results are provided to illustrate the effectiveness of the proposed technique.

Influence of Agricultural Irrigation Activity on the Potential Risk of Groundwater Pollution: A Study with Drastic Method in a Semi-Arid Agricultural Region of China

Agricultural irrigation strongly affects groundwater pollution in cultivated areas. Groundwater vulnerability was evaluated using the DRASTIC method by considering agricultural activities that affect water infiltration and pollutant transport to the groundwater. Three scenarios, using different water recharge sources and calculation methods, were considered for the Tongliao area of northern China. For Scenario 1, only precipitation contributed to the net recharge estimation and ~33.77% of the area was under high pollution risk. For Scenarios 2 and 3, both precipitation and irrigation return water were considered for net recharge estimations. The fractional areas of high pollution risk regions were 40.60% and 19.22% for Scenarios 2 and 3, respectively. The modified infiltration coefficients for this study area were used in Scenario 3, and the fractional area of the high-risk region was 21.38% lower than for Scenario 2. The use of empirical infiltration coefficients in Scenario 2 overestimated the water infiltration ability in the cultivated areas, which also overestimated the fractional area of high-risk regions in this study. Accurate assessment of the impact of agricultural activities on the groundwater pollution risk is essential for cultivated areas. Emphasis should be placed on the calculation method of proper parameters for DRASTIC model construction.

Strain Variability of Listeria monocytogenes under NaCl Stress Elucidated by a High-Throughput Microbial Growth Data Assembly and Analysis Protocol.

Listeria monocytogenes causes the severe foodborne illness listeriosis and survives in food-associated environments due to its high stress tolerance. A data assembly and analysis protocol for microbial growth experiments was compiled to elucidate the strain variability of L. monocytogenes stress tolerance. The protocol includes measurement of growth ability under stress (step 1), selection of a suitable method for growth parameter calculation (step 2), comparison of growth patterns between strains (step 3), and biological interpretation of the discovered differences (step 4). In step 1, L. monocytogenes strains (n = 388) of various serovars and origins grown on media with 9.0% NaCl were measured using a Bioscreen C microbiology reader. Technical variability of the growth measurements was assessed and eliminated. In step 2, the growth parameters determined by Gompertz, modified-Gompertz, logistic, and Richards models and model-free splines were compared, illustrating differences in the suitability of these methods to describe the experimental data. In step 3, hierarchical clustering was used to describe the NaCl tolerance of L. monocytogenes measured by strain-specific variation in growth ability; tolerant strains had higher growth rates and maximum optical densities and shorter lag phases than susceptible strains. The spline parameter area under the curve best classified "poor," "average," and "good" growers. In step 4, the tested L. monocytogenes lineage I strains (serovars 4b and 1/2b) proved to be significantly more tolerant toward 9.0% NaCl than lineage II strains (serovars 1/2a, 1/2c, and 3a). Our protocol provides systematic tools to gain comparable data for investigating strain-specific variation of bacterial growth under stress.IMPORTANCE The pathogen Listeria monocytogenes causes the foodborne disease listeriosis, which can be fatal in immunocompromised individuals. L. monocytogenes tolerates several environmental stressors and can persist in food-processing environments and grow in foodstuffs despite traditional control measures such as high salt content. Nonetheless, L. monocytogenes strains differ in their ability to withstand stressors. Elucidating the intraspecies strain variability of L. monocytogenes stress tolerance is crucial for the identification of particularly tolerant strains. To enhance reliable identification of variability in bacterial stress tolerance phenotypes, we compiled a large-scale protocol for the entire data assembly and analysis of microbial growth experiments, providing a systematic approach and checklist for experiments on strain-specific growth ability. Our study illustrated the diversity and strain-specific variation of L. monocytogenes stress tolerance with an unprecedented scope and discovered biologically relevant serovar- and lineage-dependent phenotypes of NaCl tolerance.

Numerical simulation of high-strength concrete under uniaxial/triaxial compression based on meso-scale model

According to the meso-scale characteristics and structural composition of concrete, a three-dimensional finite element mesoscopic model is established based on the random aggregate generation method and the background grid projection method. Based on the improved Ottosen yield conditions, the stress-strain curves and damage parameter data of concrete are calculated, and the CDP model is applied to carry out numerical simulation under static uniaxial and triaxial compression conditions. The results show that the stress-strain curve obtained from the numerical simulation is basically consistent with the experiment, and the crack development along the ITZ can be observed in the meso-scale model, which is consistent with the experimental details. It is proved that the modeling method and parameter calculation method in this paper is accuracy and have good applicability.

The use of the localization method for calculation of the robust PID regulator parameters for unmanned aircraft servo motor

The problem of controlling a typical nonlinear servo motor of an unmanned aercraft with non-stationary parameters using a robust PID controller is considered. The procedure for calculating the parameters of a robust PID controller based on the localization method (further - LM PID controller) for continuous and discrete control systems is studied. The influence of disturbing factors (internal and external) acting on the servo motor is considered. It is established that the main perturbations acting on the servo drive include internal perturbations, which are changes in the time constant and its gain from the temperature of the environment and the quality of the supply voltage. The simulation in the class of linear and nonlinear continuous systems showed that a servo drive with a ML PID controller has the property of robustness in the working range of changes in both the input signal and the parameters of the servo drive and controller. Simulation results showing the research are presented. When describing a servo motor with an LM PID controller in the class of linear discrete systems, its robustness is limited by a narrow range of variation of both its parameters and the quantization period of the input signal. As the degree of uncertainty in the parameters of the servo motor increases (approaching the working range of their change), the discrete system loses stability. For the synthesis of robust control circuits of an unmanned aercraft with given characteristics, mathematical dependences of the settling time and static error of a typical servo motor with LM PID controller from the quantization period of the input signal and the degree of uncertainty in its parameters are presented.

Optical Spectral Filter Based on a Deep Periodic Relief Reflection Structure

A filter based on a reflecting periodic relief diffraction structure with a relief depth of greater than one half of optical wavelength is proposed. The input-output power transfer coefficient is studied versus the optical wavelength. The filter can be configured to completely suppress radiation at a specified wavelength, and the spectral characteristic can be changed due to variation in the angle of incidence of the input beam. A method for calculation of the filter parameters is proposed, and a filter that suppresses radiation at a specified wavelength and transmits radiation at another wavelength is calculated. The filter is easy-to-implement in both visible and IR spectral ranges.

Online Calibration of Polytomous Items Under the Graded Response Model.

Computerized adaptive testing (CAT) is an efficient testing mode, which allows each examinee to answer appropriate items according his or her latent trait level. The implementation of CAT requires a large-scale item pool, and item pool needs to be frequently replenished with new items to ensure test validity and security. Online calibration is a technique to calibrate the parameters of new items in CAT, which seeds new items in the process of answering operational items, and estimates the parameters of new items through the response data of examinees on new items. The most popular estimation methods include one EM cycle method (OEM) and multiple EM cycle method (MEM) under dichotomous item response theory models. This paper extends OEM and MEM to the graded response model (GRM), a popular model for polytomous data with ordered categories. Two simulation studies were carried out to explore online calibration under a variety of conditions, including calibration design, initial item parameter calculation methods, calibration methods, calibration sample size and the number of categories. Results show that the calibration accuracy of new items were acceptable, and which were affected by the interaction of some factors, therefore some conclusions were given.

Аutomatisation of Calculation Method of Technological Parameters of Wiredrawing with Account of Speed Factor and Material Properties

The article presents the mathematical model worked out for calculating the operating force of the wire drawing. The solution of the problem was achieved by dividing the wire work piece material in the deformation zone into an infinitely small finite elements ij; and, by parting the working area of the die geometry, consisting of crimping cone, drawing cylinder and the radius of curvature between them into infinitely small linear sections. The authors described the conditions for continuity at the finite element line, the dependencies required to determine the geometric grid sizes. To determine the total modified draw force, the authors obtained formulas to describe the stress condition at each point of the finite element, based on the motion equations, equations of velocity fields, the incompressibility condition, the deformation rate intensity, taking into account the speed factor and viscoplastic properties of the work material. The article presents the adequacy of the proposed model.

ТРЕБОВАНИЯ К ОЦЕНКЕ НАДЕЖНОСТИ ПОДДЕРЖИВАЮЩИХ КОНСТРУКЦИЙ НЕСУЩЕГО И КОНТАКТНОГО ПРОВОДА

Increased requirements are set to catenary suspension of electrified railways on all stages of life cycle. Big influence on its correct operation is rendered by supporting constructions. The paper presents an analysis of operation of supporting constructions such as catenary poles, cantilevers and pull-offs. As a result, the authors proved the necessity to apply a special method for calculation of reliability parameters, which will allow creating an accurate system of catenary section maintenance.

Increasing the productivity of a plant for moisture evaporation from oil sludge by application of efficient method for technological parameters calculation

The paper presents the method of heat calculation of recovery stages for the plant of moisture evaporation from oil sludge. It enables to increase the plant power and reduce fuel consumption per one unit of evaporated moisture in heating boiler.

A Wind Farm Equivalent Method Based on Multi-View Transfer Clustering and Stack Sparse Auto Encoder

Large-scale wind farm (WF) constitutes dozens or even hundreds of wind turbines (WTs), making it complex and even impractical to develop each individual WT in detail when building WF model. Thus, the equivalent model of WF, with a reasonable reduction of the detailed model, is essential to be developed. In this paper, we propose a multi-view transfer clustering and stack sparse auto encoder (SSAE) based WF equivalent method, which can be used in the low voltage ride through (LVRT) analysis of WF. First, to obtain distinguishable deep-level and multi-view representation of wind turbine (WT), stack sparse auto encoder (SSAE) is used to extract features from the time series of several WT physical quantities, and these features are used as the clustering indicator (CI). Then, a multi-view transfer FCM (MVT-FCM) clustering algorithm, which combines transfer learning with multi-view FCM (MV-FCM), is put forward for WTs clustering. Two transfer rules are designed in this algorithm, and the clustering center and membership degree in the source domain are transferred to guide the clustering process of target domain samples. Finally, the calculation method of equivalent parameters is presented. To verify the effectiveness of the proposed method, a modified actual system in East Inner Mongolia of China is utilized for case study, and the performance of the proposed model is compared with several state-of-the-art models. Simulation results show that the equivalent errors of the proposed model decrease at least 3% when comparing with other models. Also, the error fluctuations are within 6% under different simulation conditions, which illustrates the well-performed robustness of the proposed model.

Estimation of usage efficiency of freon-steam turbines in mine energy complexes

Increase of operating efficiency of mine energy complexes is an actual scientific and technical problem. Systems that utilize energy of low-potential sources and have freon-steam turbines are suggested to be included in mine energy complexes. Principles of selection of freons as working fluids in energy systems are suggested in the paper. Usage of some thermal equations of state for defining thermal and physical properties of freons is analyzed. Equation of isentropic process for the thermal Redlich–Kwong equation of state is obtained. Calculation of energy efficiency of a system with a freon-steam turbine for selected variants of usage of working fluids is performed. A calculation method of thermodynamic parameters that are necessary for energy conversion efficiency estimation of specific freons in a system of useful utilization of energy is developed. Analysis of results indicates that usage of ozone-safe and fire-safe freons in energy utilization systems of low-potential sources with a possibility of utilization of additional waste heat, which was not used in the past, allows increasing the operating efficiency of mine energy complexes.

Интенсификация работы систем водоснабжения и водоотведения г. Нижнеудинска

The paper proposes an approach to intensifying the operation of water supply and sanitation systems. The work was conducted using electronic modelling, calculation methods of hydraulic parameters and numerical modelling, as well as optimization of technical solutions for adjustment of operation modes, minimization of water leakage, pressure stabilization in the network, elimination of blockages and failures of regulating and stop valves. The efficacy of the proposed approach was demonstrated by the example of the city of Nizhneudinsk. As a result of the conducted research, information and computing systems and complexes were developed for simulating different modes of operation, assessing the performance, reliability and regime controllability of water supply and wastewater disposal systems, storing, analysing and accumulating information on the state of the system under analysis and its individual parameters. Such an approach served as a basis for developing a prospective scheme of development and reconstruction of the city water supply and sewage systems and provided an automated control system of its technological processes.

Virtual-Vector-Based Model Predictive Current Control of Five-Phase PMSM With Stator Current and Concentrated Disturbance Observer

The finite control set model predictive current control(FCS-MPCC)can significantly improve the dynamic performance of the five-phase permanent magnet synchronous motor (5P-PMSM), but its control performance highly depends on the accuracy of the model parameters. The parameter error compensation based on the first-order sliding mode observer can improve the robustness of FCS-MPCC under Model parameter mismatch. The introduction of the sign function leads to chattering in the observation results. In order to eliminate this chattering, a first-order low-pass filter needs to be added for compensation. However, the introduction of filters will increase system design difficulty and bring system delays, which will affect the compensation effect. Therefore, a second-order sliding mode observer, based on the variable-gain Super-Twisting algorithm, is proposed to realize the parameter error estimation and one-beat delay compensation in this paper. By establishing the Lyapunov function, the stability proof of the proposed observer, and the calculation method of the observer parameters are given. Besides, the third harmonic current can be suppressed, and the computational burden of the control unit can be reduced by controlling the proportion of medium vector and large vector reasonably. According to the deadbeat control, the optimal virtual voltage vector action time in each cycle is obtained, which improves the tracking ability of the reference current. At last, Extensive experimental results validate that i) the proposed observer can significantly improve the robustness of model predictive current control even under parameters mismatch; ii) the proposed control method can effectively enhance the dynamic performance of the 5-phase PMSM.

Design calculation model of oil fluid property parameter knowledge database for production logging

The fluid property parameter calculation affects the accuracy of the interpretation the accuracy, in the interpretation of the liquid production profile. Therefore, it is particularly important to accurately calculate the physical property parameter values, in the establishment of the fluid property parameter expert knowledge base system. The main physical parameters include the following calculation methods of the oil. The oil property parameter conversion formula mainly studies the formulas such as bubble point pressure, dissolved gas-oil ratio, crude oil volume coefficient, crude oil density, crude oil viscosity, and crude oil compression coefficient. Design expert knowledge base system, it is based on the calculation methods of these physical parameters. A computational fluid property parameter model is constructed by training production log sample data. Finally, the interactive and friendly product interpretation software model was developed in 9 wells’ data. The design calculation model can increase the accuracy to achieve 95% of oil fluid property parameter. Accurately calculate fluid property parameter values.

Algorithm and Design Methodology for Energy-Efficient Sheet Products Production Technology

The work presents a calculation method for technology parameters of the continuous cold rolling process of wide steel strips, based on the determination of such reductions by stands and interstand tension, at which the technological process will be ensured with maximum productivity and minimum energy consumption. A method for calculating the rolling parameters is proposed, which will provide the minimum level of energy consumption by the main drives’ motors of the rolling stands at the maximum productivity of the continuous mill by eliminating vibrations in the working stands. The created methodology can be used as a base for the software of continuous mills.

A new approach for predicting critical gas rate in condensate gas wells

We established a new model for predicting the critical liquidcarrying flow rate of a condensate gas well. The variations of the two parameters (critical Weber number and drag coefficient) were added as improvements to previous models, and the calculation methods of the above parameters were also added. Calculations were analysed in 30 condensate gas wells of the Xinjiang field. The correct prediction rate of the new model is 90%, with the status of 27 wells correctly predicted (loading/unloading), and the calculation accuracy of the new model is 6%~70% higher than that of previous models (Wan, Zhao, and Li). The research in this paper is of vital significance in guiding well stimulation (e.g., coiled tubing velocity string) to avoid liquid loading and increase gas recovery rate. [Received: June 14, 2017; Accepted: February 1, 2018]

Optimization of Structural Parameters for a New-Type Magnetic Integration Structure CRT Considering Loss and Cost

The optimization of structural parameters of controllable reactor of transformer type (CRT) is of great significance for improving its economic benefits. This paper takes the new-type magnetic integration structure CRT as the research object. Qualitative analysis is employed to explore the relationship between loss, cost and structural parameters of CRT. The optimization model of structural parameters is established with the objective of minimizing cost and loss. The genetic algorithm is used to optimize the structural parameters of CRT. Based on this, a new economic calculation method of CRT's structural parameters is proposed. The results show that the optimization of CRT's structural parameters aiming at minimizing cost and loss is essentially to optimize the cross-sectional area of iron core and the length of winding coil. A new method for calculating CRT's structural parameters based on genetic algorithm optimization has more reasonable calculation results. With the increase of CRT operating time, the proportion of CRT use costs caused by loss will gradually increase. The methods and conclusions used in this paper provide some theoretical guidance for the structural design and optimization of CRT.

Hardware-in-the-loop Implementation of ANFIS based Adaptive SoC Estimation of Lithium-ion Battery for Hybrid Vehicle Applications

Abstract This paper presents an effective method to estimate the state of charge (SoC) of a Lithium-ion battery. This parameter is very crucial as it indicates the performance and health of the battery. The battery SoC estimation equivalent circuit provided in MATLAB has been modified by adding the 3- RC pairs in series with its internal resistance. The values of the RC pairs have been calculated mathematically by solving the circuit model, based on charging and discharging dynamics of the battery. The values of these parameters have also been optimized using a “lsqnonlin” function. The SoC of the battery is estimated using the combination of coulomb counting and open-circuit voltage methods to minimize the error in estimation. The obtained SoC is further corrected for errors using ANFIS based algorithms. The effect of temperature has also been accounted for modelling the battery and in SoC estimation. These obtained SoCs for 3 cases, i.e. without RC/with RC pairs and then tuned with ANFIS based optimization are compared for the same load. The parameter calculation method adopted here results in an efficient and accurate model that keeps track of correct battery SoC. The complete system is validated in real-time using hardware-in-the-loop laboratory setup.

An Equivalent Magnetic Circuit Model of PMSM Demagnetization Fault

The PMSM (permanent magnet synchronous motor) demagnetization fault simulation model and the equivalent magnetic circuit model under normal operation were established, and the calculation method of each parameter on the equivalent magnetic circuit model was analyzed. Then the demagnetization factor that represents the demagnetization severity was introduced, and the calculation method of parameter under the fault condition of the PMSM was deduced, and the air gap flux densities of the PMSM under different working conditions were calculated. At last, the validity of this model was verified by comparing the results of the partial demagnetization simulation and the equivalent magnetic circuit model.