The Microwave Imager Combined Active/Passive (MICAP) is a suit of active/passive instrument package, which has been proposed for demonstrating the capability of remote sensing the sea surface salinity (SSS), sea surfa...
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ISBN:
(纸本)9781509049516
The Microwave Imager Combined Active/Passive (MICAP) is a suit of active/passive instrument package, which has been proposed for demonstrating the capability of remote sensing the sea surface salinity (SSS), sea surface temperature (SST) and wind speed (WS). In this paper, a nonlinear optimization algorithm for simultaneous retrieval of the above parameters is described. The sensitivity of active/passive microwave observations to SSS is analyzed using the nonlinear optimization algorithm. The results show that the root mean square (RMS) error on the retrieved SSS estimated by using the nonlinear optimization algorithm is enough to meet the requirement of Ocean Salinity Satellite. This is submitted for the special session of "New Developments of Chinese Oceanographic and Meteorological Satellites "
Identification of stiff nonlinear systems is considered as one of the challenging tasks and research community is providing promising solution for identification of these systems. Researchers have concluded that integ...
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Identification of stiff nonlinear systems is considered as one of the challenging tasks and research community is providing promising solution for identification of these systems. Researchers have concluded that integration of fractional calculus provides better insight and understanding of complex systems by keeping the previous history. In this study, nonlinear marine predator optimizationalgorithm (NMPA) is used for the identification of fractional Hammerstein control autoregressive system (FHCAR) with Gaussian as well as impulsive noise. Further, a practical example of heat exchanger system modeled with FHCAR structure, is considered to analyze the knacks of NMPA in terms of convergence, robustness and stability. Grunwald-Letnikov's concept of fractional calculus derivative is used to transform standard Hammerstein control autoregressive system into FHCAR system. Mean square error-based fitness function is used to examine the performance of NMPA for identification of 4th order nonlinear FHCAR system for all three case studies i.e., FHCAR with Gaussian noise, FHCAR with impulsive noise and heat exchanger system identification. The performance of NMPA is observed in terms of fast convergence, accuracy, stability, robustness and accuracy in estimation of correct parameters of the system for multiple noise scenarios and the superiority is endorsed through comparison with the recent counterparts i.e., Gazelle optimizationalgorithm, Runge Kutta optimization method, Whale optimizationalgorithm, Harris Hawks optimizationalgorithm and African vulture optimizationalgorithm.
In the field of visual metrology, achieving coordinate system unification among non -overlapping multi -camera systems in wide field -of -view scenarios poses significant challenges due to the absence of overlapping f...
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In the field of visual metrology, achieving coordinate system unification among non -overlapping multi -camera systems in wide field -of -view scenarios poses significant challenges due to the absence of overlapping fields of view. This paper presents a novel calibration method for such multi -camera systems utilizing a ruler equipped with double -layer circular encoded landmarks. The fabrication of the ruler is simple, and its length covers the entire multi -camera measurement system, rendering the calibration process convenient. To calibrate the cameras, the ruler is positioned in front of the target cameras, and images of the ruler are captured by the multi -cameras. By establishing the initial transformation relationships between the non -overlapping cameras and the ruler's coordinate system, the proposed method efficiently determines the inter -camera transformations. Subsequently, by moving the ruler to different positions and capturing corresponding images, the distances between the encoded center points on the ruler and other encoded points, as captured by the non -overlapping cameras, are kept constant. An optimization -based objective function is formulated to minimize the three-dimensional distances between the measured encoded center points, thereby refining the initial transformation relationships. Combining the coplanarity constraint of the coding center points with the extrinsic results obtained through distance optimization, a secondary optimization was conducted to obtain the final transformation parameters. Experimental results demonstrate the simplicity and versatility of this method, which does not rely on complex constraints. Moreover, it exhibits high calibration accuracy, with maximum distance errors between ruler points and a fitting standard plane error both below 0.275 mm and 0.132 mm, respectively. Following multiple experimental iterations, the average disparity between the radius of the standard cylinder measured via line laser scanning
To deeply analyze the difference between styrene-butadiene-styrene (SBS)-modified asphalt and base asphalt in ultraviolet (UV) aging performance, an atomic force microscope was used to carry out an accurate analysis o...
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To deeply analyze the difference between styrene-butadiene-styrene (SBS)-modified asphalt and base asphalt in ultraviolet (UV) aging performance, an atomic force microscope was used to carry out an accurate analysis of the bee structural characteristic parameters of two kinds of asphalt experiencing different UV aging time duration. With the advantages of the Levenberg-Marquardt (LM) algorithm and universal global optimization (UGO) algorithm, the relationship between the microscopic characteristic value and the performance index of asphalt under UV aging was constructed. The results show that the physical parameters of the bee structure of asphalt are closely related to the macroscopic properties of asphalt materials. Because the number of bee structures of SBS-modified asphalt is significantly more than that of base asphalt, and in the process of UV aging, the absolute height and area of the bee structure fluctuate less, and the adhesion force fluctuates with aging time. The decreasing trend makes SBS-modified asphalt significantly better than base asphalt in anti-UV aging performance. Under different UV aging time durations, the penetration and aging index (AI) of the two kinds of asphalt showed an excellent linear relationship with the microscopic indexes measured by atomic force microscope (AFM). Through the nonlinear optimization algorithm, the prediction equations of the morphology height and adhesion force of the two kinds of asphalt under different aging stages were successfully derived. The research results can provide theoretical support for the optimization and improvement of the UV aging performance of SBS-modified asphalt.
The orderly charging load forecasting for Electric Vehicles (EVs) in urban residential areas(RAs) is of significance for planning the charging facilities and analyzing the load carrying capacity of distribution networ...
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ISBN:
(数字)9781665450669
ISBN:
(纸本)9781665450669
The orderly charging load forecasting for Electric Vehicles (EVs) in urban residential areas(RAs) is of significance for planning the charging facilities and analyzing the load carrying capacity of distribution network as well as its expansion and reconstruction. In this paper, a mid-and long-term load forecasting method for EVs orderly charging in RAs is proposed based on the number and charging probability of EVs. nonlinear programming is used to solve the optimization objective function of orderly charging, and the typical daily load characteristics in urban RAs are used to forecast the orderly charging load of EVs and the overall load in the station area on working days and at weekends in the past three years and the target year. Simulation results show that orderly charging can improve the capability of distribution network in residential areas to accommodate EVs and postpone its upgrade and reconstruction time.
A set of superconducting shim coils for a 400 MHz nuclear magnetic resonance spectrometer was designed, analyzed and constructed. A nonlinear optimization algorithm was employed for the calculation of the optimal cond...
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A set of superconducting shim coils for a 400 MHz nuclear magnetic resonance spectrometer was designed, analyzed and constructed. A nonlinear optimization algorithm was employed for the calculation of the optimal conductor shapes and positions of superconducting shim coils. In the optimization, a number of system parameters, including field errors, axial size of coils and spherical harmonics have been constrained to acceptable levels. The results have the property of combining best field quality and also controlling the desired harmonics terms strength. The proposed methodology can also be used to design superconducting and resistive shim coils for other homogeneous magnet systems.
Due to the large number of electric vehicles (EVs) connected to the distribution network of residential areas (RAs), community charging has become a major constraint. The planning of the distribution network in RAs ne...
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Due to the large number of electric vehicles (EVs) connected to the distribution network of residential areas (RAs), community charging has become a major constraint. The planning of the distribution network in RAs needs to consider the orderly charging load of EVs. In the current study, an orderly charging planning method for the charging posts and distribution network of RAs was proposed. First, a charging load forecasting model based on the travel characteristics, charging time, and ownership of EVs in RAs was established. Then, a hierarchical orderly charging optimization method, including a distribution network layer and EV access node layer, was devised. The upper layer optimizes the distribution network. The objective function is the minimum variance of the overall load in the RA and the constraint conditions satisfy the overall charging load demand and the capacity of the distributed network. The lower layer optimizes the EV access nodes. The objective function is the minimum variance of the node access load, and the constraint conditions are to meet the regional charging load demand and the optimal power balance demand transmitted from the upper layer to the lower layer. A nonlinear optimization algorithm is employed to solve these objective functions. An IEEE 33 node example was used to obtain the orderly charging power load curves for weekdays and weekends in RAs, and the simulation results prove the effectiveness of the proposed method.
Under the background of serious wind and solar energy curtailment in China, flexibility modification of coal-fired supercritical units is selected as an effective technical path to provide space for renewable energy i...
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Under the background of serious wind and solar energy curtailment in China, flexibility modification of coal-fired supercritical units is selected as an effective technical path to provide space for renewable energy into the grid. Modeling of coordinated control system in low load has yet to be conducted to date. In this work, a simplified dynamic model for coal-fired once-through boiler-turbine unit aimed at low load working condition is built up. First, the major model structure is established mainly based on mass and energy balance laws as well as thermodynamic equilibrium of important parameters combined with the analysis of operation characteristics. Then, the unknown parameters in the model are estimated by regression analysis, statistical analysis, and nonlinear optimization algorithm. Comparison results between measurement and simulation results show that the model has acceptable accuracy and, importantly, also captures the essential dynamic characteristics of units.
Operational optimization is the key to energy reduction of the district heating (DH) system. Poor hydraulic performances of the DH network will largely increase the energy consumption. However, for most meshed DH netw...
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Operational optimization is the key to energy reduction of the district heating (DH) system. Poor hydraulic performances of the DH network will largely increase the energy consumption. However, for most meshed DH networks with multiple heat sources, the optimal hydraulic conditions are usually not achieved. In this paper, the hydraulic performance optimization problem of meshed DH network with multiple heat sources was proposed. In order to solve the problem, the General Reduced Gradient (GRG) algorithm was adopted to minimize the total pump power through optimizing the pump frequencies and substation valve openings of the DH network. The hydraulic performances of the GRG algorithm based optimal control (OC) strategy were compared with the traditional constant pressure difference control (CPDC) and the constant speed control (CSC) strategies. Results shows that in comparison with the CPDC and CSC strategy, the total pump power can be reduced by 20% and 65% respectively, when applying the OC strategy. And the hydraulic intersection point of the DH network was changeable to reallocate the serving areas of heat sources and optimize the total pump power. Besides, increasing the pump efficiency without considering the hydraulic constraints of the DH network may not lead to optimal conditions. (C) 2017 Elsevier Ltd. All rights reserved.
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