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Using GA - BP Coupling Algorithm to Predict the High-performance Concrete Mechanical Property
Libing Jin,Jie Duan,Tai Fan,Pengfei Jiao,Tianyun Dong,Qiang Wu 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.2
As a cementitious composite, concrete’s property depends on the matrix generated from cement hydration and the dispersed phases such as aggregates. Compression strength is an important mechanics performance index of concrete quality, especially the High-performance Concrete (HPC). However, owing to the expensive cost of test and the existence of high-dimensional nonlinear mapping between compression strength and basic materials, it is uneasiness to precisely forecast the compression strength value of HPC by general formula method. In this research, a novel machine learning system, Genetic Algorithm and BP Neural Network (GA-BPNN) coupling algorithm, is offered to predict the compression strength of HPC. GA-BPNN coupling algorithm model used 181 groups of HPC mixture data to determine 8 factors affecting its compression strength (i.e., Water, Portland Cement, Water-binder Ratio, Fine Aggregate Ratio, Air-entraining Agent, Fly Ash, Silica Fume, and Superplasticizer) as the input variables of the model, while compression strength was set as the output variable. In addition, 166 sets of training set data were segmented into training, validation and test set again, and BP neural network (BPNN) was compared with GA-BPNN to verify the generalizationcapacity of the model in this research. By forecasting the compression strength of 15 test sets, the average relative error is only 0.902%. Finally, the sensitivity of input variables of GA-BPNN model was analyzed by using Gray Relational analysis (GRA) method. Six models were established to research the impact of sensitivity and quantity of input variables on model performance by ignoring individual input variable. The research is shown that GA-BPNN model not only has the powerful nonlinear mapping ability of BPNN, but also has the global search optimization ability of GA, and showed stronger robustness and prediction potential in the assessment of compression strength value of HPC. The sensitivity analysis shows that, to compression strength of HPC, Cement, Water and Water-binder ratio has a sensitivity score of 0.8166, 0.70122, 0.66772, respectively while Fly Ash has the lowest sensitivity.
LCL APF based on fractional-order fast repetitive control strategy
Pan, Guobing,Gong, Fei,Jin, Libing,Wu, Hao,Chen, Sihan The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.10
The LCL type active power filter (APF) with a traditional repetitive controller has drawbacks in terms of poor dynamic performance, large steady-state error, and difficult digital implementation. A fast repetitive control (RC) algorithm was proposed in this paper in an effort to improve the APF dynamic performance without worsening its stability. To eliminate the non-integer delay of the traditional RC, a fractional-order RC algorithm based on the Lagrangian Interpolation was developed. The proposed fast fractional-order RC (FFORC) strategy only needs 1/6 delay time when compared to the traditional RC. In addition, it can track the error signal quickly and obtain a higher steady-state accuracy. Furthermore, the double current loops control method with grid side current and inverter side current feedback is proposed to achieve active damping of the resonance peak of the LCL filter, which ensures that the APF system is stable. Simulation and experimental results are presented to verify the performance of the dynamic response and steady-state accuracy of the proposed FFORC strategy.
Harmonic Winding Factors and MMF Analysis for Five-phase Fractional-slot Concentrated Winding PMSM
Kang, Huilin,Zhou, Libing,Wang, Jin Journal of International Conference on Electrical 2014 Journal of international Conference on Electrical Vol.3 No.1
To enhance torque density by harmonic current injection, optimal slot/pole combinations for five-phase permanent magnet synchronous motors (PMSM) with fractional-slot concentrated windings (FSCW) are chosen. The synchronous and the third harmonic winding factors are calculated for a series of slot/pole combinations. Two five-phase PMSM, with general FSCW (GFSCW) and modular stator FSCW (MFSCW), are analyzed and compared in detail, including the stator structures, star of slots diagrams, and MMF harmonic analysis based on the winding function theory. The analytical results are verified by finite element method, the torque characteristics and phase back-EMF are also taken into considerations. Results show that the MFSCW PMSM can produce higher average torque, while characterized by more MMF harmonic contents and larger ripple torque.
Zhiguo Xia,Peng Du,Libing Liao,Guowu Li,Shuai Jin 한국물리학회 2010 Current Applied Physics Vol.10 No.4
Eu2+ and Mn2+ co-doped calcium aluminate silicate chloride phosphors with the chemical composition of Ca3Al2Si2O8Cl4:Eu2+, Mn2+ have been prepared by a solid-state method, and their luminescence properties have been investigated by tuning the En2+/Mn2+ ions concentration. The phase formation and microstructure of Ca3Al2Si2O8Cl4:Eu2+, Mn2+ phosphors have been illuminated by XRD and SEM analysis. Photoluminescence (PL) spectrum reveals that Ca3Al2Si2O8Cl4:Eu2+ exhibits a strong blue emission band centered at 431 nm, while Ca3Al2Si2O8Cl4:Eu2+, Mn2+ can emit bluish-white light by adjusting the Mn2+ content appropriately. The energy transfer mechanism involving Eu2+–Mn2+ have also been investigated.
Ben, Tong,Wang, Jin,Chen, Long,Jing, Libing,Yan, Rongge The Korean Institute of Power Electronics 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.11
The amorphous alloy used in a switched reluctance motor core can greatly improve the efficiency of the motor. However, its large magnetostrictive coefficient and strong stress sensitivity (i.e., inverse-magnetostriction effect) increase the core vibration and limit the precise control capability of the electrical signals. A vibration reduction method based on the inverse-magnetostriction effect is proposed to control the electromagnetic vibration of a switched reluctance motor with amorphous alloy cores (SRMA). First, a nonlinear magnetostriction and inverse-magnetostriction effect model (NMIE model) of an amorphous alloy and the compressive stress applied structure for the stator teeth are proposed. Then, considering the influence of static compressive stress and dynamic electromagnetic stress on the magnetic properties of the core material, a two-way dynamic electromagnetic force coupling model of the SRMA is constructed and solved. Finally, the vibration characteristics of the SRMA core are calculated. The obtained results show that the radial electromagnetic stress of the improved structure is reduced by 33.6%, which verifies the feasibility of the proposed vibration reduction method.