bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Improved Adaptive Load Shedding Control Strategy for Primary Frequency Regulation of Wind Power Generation System
Authors: Li Xudong , Li Hua , Ma Chunzhe , Meng Yongqing , Hu Yahan , Duan Ziyue 
Published: December 2022

Abstract
With the continuous improvement of the proportion of wind power generation, the volatility and uncertainty of wind power pose a serious threat to the stable operation of the power system. However, the traditional primary frequency regulation strategy does not fully consider the influence of wind turbine inertia. In addition, it may cause the secondary frequency drop if the instantaneous power of the wind turbine drops too much during the speed recovery. To solve this problem, this paper proposes an adaptive primary frequency regulation strategy for the mobile load shedding power tracking curve. Under this strategy, by controlling the output active power reference value, the kinetic energy stored in the rotor is fully released to support the grid frequency for a short time. Then, in the process of rotor speed recovery, the frequency secondary drop can be alleviated by moving the load-shedding power tracking curve. Finally, the simulation results in MATLAB/Simulink verify the rationality of the proposed adaptive load-shedding control strategy.
The Application of Posterior Error Criterion to Dynamic Equivalence Evaluation
Authors: Sun Zhiyuan , Liu Mosi , Zheng Kun 
Published: December 2022

Abstract
The scale and complexity of the power system are increasing, which carry out a lot of difficulty and effort to detailed simulation of the whole system, so effective dynamic equivalence is the premise of the modeling of electromagnetic transient simulation of large power systems. This paper targeting at the present situation of lack quantization standard in the dynamic equivalence, this paper took the posterior error criterion of grey forecasting model into the Dynamic Equivalence Evaluation, then proposed more detailed and exactly quantization standard appraisal index system, further perfect the error evaluation system of dynamic equivalence efficiency.
A Chance-constrained Optimization Combined with Soft Open Points and Volt/Var Control under Uncertainties in Distribution Networks
Authors: Wang Jing , Pan Zhiyuan , Liu Jing , Li Tianhang , Li Guanghong , Zheng Xin 
Published: December 2022

Abstract
With more and more photovoltaics (PVs) integrated into distribution networks, their drastically fluctuating nature may lead to voltage limits violation. However, the existing studies only focus on capacitor bank dispatching, which cannot address the drastic fluctuation of PV outputs. To adapt to the fast and continuous variation of PVs outputs in the distribution networks, this paper proposes a joint optimization of capacitor banks (CBs) and soft open points (SOPs). A chance-constrained model is established including the nonlinear equations of SOPs. Then, the second-order conic is applied to SOPs equations for efficient and accurate solving of the model. Finally, a cluster satisfying the given confidence level is formed by a proposed heuristic method to improve calculation efficiency. The numerical simulations on distribution networks show the efficiency and accuracy of the proposed algorithm over the existing methods.
An approach to planning the extension of distributed power supplies to the distribution network, taking into account uncertainty
Authors: Lin Huaide 
Published: December 2022

Abstract
At present, there is a problem of high active line network loss in the distribution network expansion planning method for distributed power supply access, and a distributed power supply access distribution network expansion planning method that accounts for uncertainty is designed to improve this phenomenon. According to the coverage of the electricity consumers’ sites, the available supply capacity of the distributed power sources is evaluated, the wind speed is discounted by the hub height of the wind turbines, the uncertainty is taken into account to build a correlation model, the number of nodes in the grid is fully considered, the grid operation characteristics are extracted, the voltage of the nodes along the line is simplified and the distribution network expansion planning model is optimized. Test results: The method designed here has the lowest average active line network loss of 112.58 kW, which is 10.83 kW, 10.3 kW and 12.85 kW less than the other three methods respectively, indicating that the method designed here performs better with full consideration of the uncertainties.
A novel AC-DC hybrid microgrid architecture and control strategy for electric vehicle swap station
Authors: Zheng Zhilong , Liu Rui , Qi Yanlong , Lin Haisheng , Hong Weizhuo , Zhu Yuquan , Xu Chaoyao 
Published: December 2022

Abstract
The characteristics of small volume, modularity, and easy expansion in solid-state transformers (SST), which makes SST widely applied in electric vehicle swapping stations. However, due to various loads and pulsed loads, voltage instability and fluctuation problems inevitably occur in electric vehicle swapping stations. Aiming at these problems, a topology structure based on a Modular Multilevel Solid State Transformer (MMC-SST) is proposed. It is the first choice for realizing the flexible power allocation of AC/DC hybrid system and the interconnection of medium and low voltage. The performance of the DC bus voltage of the charging station has been improved. Based on this topology, an energy management strategy with virtual synchronous generator (VSG) control is proposed to smoothly transition the on-grid and off-grid processes of the distributed power source. In addition, due to the frequency regulation is applied in the control system, the energy storage system has damping and inertia when the output of the new energy power generation equipment changes or load fluctuation, reducing the impact on the load energy storage equipment and improving the stability and safety of the electric vehicle charging station system. Finally, the effectiveness of the proposed topology and its control strategy in different working scenarios are verified by simulation. Simulation analysis shows that the proposed topology has good advantages in DC bus voltage stability, optimization of electric vehicle charging characteristics and load management.
A Transformer Based Complex-YOLOv4-Trans for 3D Point Cloud Object Detection on Embedded Device
Authors: Zhang Jingfeng , Song Qingzeng , Yu Jing 
Published: December 2022

Abstract
3D object detection is widely used in the field of autonomous driving. The embedded devices have few resources and low power consumption, so the existing 3D object detection algorithms are difficult to complete the detection task in the required time under some conditions. In this paper, the Complex-YOLOv4-Trans model is proposed to use point cloud data for 3D object detection. Firstly, a transformer encoder block is introduced to improve the structure of Backbone, which makes full use of its context information to improve detection accuracy. Secondly, the general convolution in Backbone is replaced with a depth-wise separable convolution, which effectively reduces the computational load of the model. Finally, Complete-IoU (CIoU) is used as the loss function, and then 8-bit model quantization is performed to speed up the inference. We select the KITTI dataset and deploy the model on NVIDIA Jetson Xavier NX by using TensorRT acceleration tools to test the methods. The mAP of Bird’s Eye View for Car is 71.79%, the mAP for 3D Detection is 15.82%, and the FPS on the NX device is 42 frames. Experimental results show that our Complex-YOLOv4-Trans can perform real-time 3D object detection tasks on low-energy embedded devices.
Multi-channel High-speed Data Acquisition System Based on Improved SPI Communication
Authors: Yang Changqing , Zhou Dawei , Lu Li 
Published: December 2022

Abstract
A multichannel high-speed data acquisition system based on improved SPI communication is designed to meet the requirements of synchronous acquisition of current and voltage parameters by master and slave control boards. The main architecture of this system is a master-slave FPGA board and AD acquisition card, and the program is developed based on the Vivado platform. Based on traditional SPI communication, this paper puts forward an improved SPI communication. By increasing the number of MISO data lines, the data transmission rate between master and slave control boards is greatly increased, and the FPGA expansion port resources are fully utilized. In addition, a data conversion module is added to the system, which can observe the acquisition results more intuitively. At the same time as high-speed data acquisition, the measurement accuracy within the specified voltage input range is high. The experimental results show that the system can realize multichannel high-speed data acquisition.
Design of Grid Communication Data Gateway Filtering System Based on Microservice Architecture
Authors: Chen Yuxu , Liu Mingwei , Ao Zhiqi , Fan Zhongkai , Liu Zhuqing 
Published: December 2022

Abstract
The grid communication data gateway filtering system has the problem of excessive memory overhead, so a grid communication data gateway filtering system based on micro-service architecture is designed. For the hardware part, the system can support mounting a U disk with a capacity of 16 G and above and use NAND FLASH to realize the expansion of solidified code and storage space. For the software part, the system can get the gateway communication parameters, calculate the bit rate of grid communication data transmission, and match a specific duty cycle. Besides, it can set the existing network port authentication mode according to the instructions, start the gateway filtering program, design the power grid communication data reliability judgment rule base, and optimize the filtering mode based on the micro-service architecture. The test results are that under the conditions of a different number of sensitive words, the average memory overhead of the designed system is 75.93 MB, indicating that the system has better overhead performance under the influence of the microservice architecture.
Fine-grained Vehicle Classification Based on Feature Augmentation
Authors: Chen Junwen , Chen Zhiyi , Tao Simiao , Xia Jing 
Published: December 2022

Abstract
Fine-grained vehicle classification is a hot research topic in the field of computer vision, which aims to recognize different models of vehicles belonging to the same brand. Limited by the large appearance differences of the same vehicle (due to different attitudes and perspectives) and small appearance differences between different vehicles, the vehicle’s reorganization performance is not high and can’t meet the real application requirements. In this paper, a Fine-grained Vehicle Classification is proposed based on Feature Augmentation (FAFCC), which focuses on mining the key discriminative parts of the object. Specifically, the FAFCC first improves the weakly supervised data augmentation network (WSDAN) by using multi-layer feature extraction and fusion instead of single-layer features. Further, the FAFCC assigns local feature weights to select key features, which can solve the problem that the discriminant features in the channel are not prominent enough and realize the high-quality compact fine-grained vehicle recognition task. The performance of the FAFCC on the fine-grained image classification tasks for vehicles has been evaluated through algorithm comparison experiments and ablation experiments. Through visual analysis, it can be seen that the introduction of each new module has optimized the loss function value and convergence speed of the model. In general, our FAFCC algorithm has a certain improvement effect compared with the original algorithm.
Performance Detection of Transformer Oil Based on Wavelet Neural Network Optimized by Sparrow Search Algorithm
Authors: Zhang Xin , Wang Zonglin , Shen Wenqiang , Guo Yongji , Chen Baoqi 
Published: December 2022

Abstract
Transformer oil is an indispensable part of the transformer. The performance of transformer oil largely determines the working condition of the transformer. Therefore, it is necessary to realize accurate and rapid detection of the physical and chemical properties of transformer oil. To realize the detection of transformer oil, firstly, the ultrasonic wave with multiple frequencies is transmitted through the transformer oil, and the physical data such as penetration velocity and attenuation coefficient in the transformer oil are detected. The parameters of the wavelet neural network were optimized using the sparrow search algorithm, and the feasibility of the model was detected using the transformer oil experimental data.
Optical, structural, morphological and chemical properties of doped TiO2 nanoparticles with FeCl3
Authors: Afonso Cátia , Segundo Iran Rocha , Lima Orlando , Landi Salmon , Homem Natália , Costa Manuel F. M. , Freitas Elisabete , Carneiro Joaquim 
Published: December 2022

Abstract
To achieve high photocatalytic activity, TiO2 nanoparticles nanoparticles require an excitation source in ultraviolet radiation. Incorporating chemical elements into the TiO2 lattice can tune its band gap, resulting in an edge-shifted red absorption to reduce energies, improving photocatalytic performance in the visible region of the electromagnetic spectrum. In this research, TiO2 semiconductor nanoparticles were subjected to a doping process using iron chloride (FeCl3) powder to activate photocatalysis under visible light and consequently improve pollutant capture. To study the effectiveness of the doping process, the main ratios (1:1), (1:1.622) and (1:3) of TiO2:FeCl3 were evaluated using Diffuse Reflectance Spectroscopy (DRS), X-ray diffraction (XRD), Fourier-Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The main results of this research show that doping TiO2 with FeCl3 shifted the absorption edge to longer wavelength values, changing the optical properties of the material and decreasing the band gap (Eg) of TiO2 compared to the undoped TiO2 (reference). There are no relevant differences between the XRD pattern of the samples with TiO2-FeCl3 and TiO2 nanoparticles (reference). The fraction of the anatase phase in doped TiO2 nanoparticles has the same magnitude as the reference TiO2. Regarding FTIR, the Fe-doping process alters the TiO2 reference spectrum, increasing the intensity of hydroxyl bonds and peaks particularly, indicating the Ti-O-Fe bond vibration.
Silicon Nitride Interferometers for Optical Sensing with Multi-micron Dimensions
Authors: Costa João , Almeida Daniel , Fantoni Alessandro , Lourenço Paulo , Vieira Manuela 
Published: December 2022

Abstract
Increasing the size of the smallest features of Photonic Integrated Circuits (PICs) to multi-micron dimensions can be advantageous to avoid expensive and complex lithographic steps in the fabrication process. In applications where extremely reduced chip size is not a requirement, the design of devices with multi-micron dimensions is potential interesting to avoid the need for e-beam lithography. Another benefit is that making the dimensions larger reduces the effect of lithographic imperfections such as waveguide surface roughness. However, the benefits do not come without limitations. Coupling the light in and out of the circuit is more challenging since diffraction gratings are not available when designing for such large dimensions. Circuit bends must have a larger radius of curvature and the existence of multimode propagation conditions can have detrimental impact in the performance of several devices, such as interferometers. In this study we perform simulations of the coupling between a lensed multimode optical fiber and a multi-micron a-SiN:H rib waveguide. Light coupling efficiency is analyzed as a function of distance variations using the FDTD method and compared with coupling to a strip waveguide. Moreover, we use numerical simulations to study the performance of a Mach-Zehnder interferometer sensitive to refractive index variations. Both the interferometer, splitters and combiners are designed with multi-micron dimensions.
Assessment of central and peripheral accommodative lag by aberrometry
Authors: Sapkota Kishor , Gomes Jessica , Franco Sandra 
Published: December 2022

Abstract
Accommodation lag is important factor for normal vision. Higher lag of accommodation may cause various ocular symptoms particularly during near tasks. In this study, the lag of accommodation was assessed in the peripheral retina and it was compared with the central accommodative lag with aberrometer. In this cross-sectional study, fifty-three young subjects with normal visual acuity and without any active ocular disease or past ocular surgery were included. Aberrations in the central and peripheral field of view up to 30° off axis from the centre in horizontal and vertical meridian in 10° steps were measured with Hartmann-Shack aberrometer with stimulation of accommodation by -2.50D lens. Accommodative stimulus and accommodative response were calculated with defocus and hence accommodative lag was obtained. Accommodative lag in the centre and periphery was compared. Repeated measure of ANOVA showed that there were significant differences in lag of accommodation in various eccentricities (F(8.912, 454.514) = 2.372, p = 0.013). Pairwise test showed that lag in the centre was similar with lag on other peripheral field of view (p > 0.05). However, accommodative lag at 10° nasal field was significantly lower than the lag at 20° temporal, 20° nasal, 30° temporaland 30° nasal (p < 0.05). Similarly, lag at 10° superior fixation was lower than lag at 20° temporal, 20° nasal, 30° temporal and 30° nasal fixations (p < 0.05). We found higher lag of accommodation in horizontal off-axis fixations in comparison to that of vertical off-axis fixations (p < 0.05). Lag of accommodation was positive correlated with vertical coma and primary spherical aberrations but negative correlated with secondary spherical aberrations (p < 0.05). Thus, Hartmann-Shack aberrometer was successfully used to assess accommodative lag in the peripheral field of view up to 60° visual field. Peripheral lag of accommodation depends up on eccentricity. Lag was found higher in horizontal off-axis fixation than at vertical fixations. Coma and spherical aberration had association with lag.
Imaging sensors for PoET: a spatially resolved solar spectroscopy instrument
Authors: Leite I , Cabral A , Abreu M , Santos N 
Published: December 2022

Abstract
The study of the Sun is an area still open in several topics of astrophysics, in a field that has seen an expansion in recent years - therefore, it is critical that collected data is thoroughly traceable and accurate to be used in new study cases or predictive models. A ground based, portable, optimized system, consisting of a Schmidt-Cassegrain telescope coupled to a refractor telescope acting as a pointing telescope, is being designed to provide high resolution imaging of smaller areas on the Sun’s surface, being able to obtain disk-resolved, high spectral resolution data, at a relative low cost (compared to large consortium developed instruments). The light collected by the telescope will be fibre-fed to a spectrograph - the injection of light in the fibre is critical and requires an imaging sensor to aid the light guiding process. The goal of the present work was to explore the best candidates for the image sensors, their architectures, requirements, and constraints, as well as their expected performance range and signal noise. The trade-off analysis between CMOS and CCD based sensors was made and it was concluded, that for the intended application, either type of architecture is admissible, provided the sensor is within desired parameters.
Innovative hybrid optical sensing design to simultaneously discriminate pressure and temperature
Authors: Freitas Fábio , Matuck Lucca , Bierlich Jörg , Ferreira Marta , Marques Carlos , Nascimento Micael 
Published: December 2022

Abstract
In this work, hybrid optical fiber sensors based on Fabry-Perot (FP) interferometer and Fiber Bragg Grating (FBG) sensors were developed to simultaneously measure two external parameters, pressure, and temperature. The proposed sensor consists of a photosensitive Single-Mode Fiber (SMF), where the FBG is recorded, and spliced to a small section of a Hollow-Core Fiber (HCF). After that, the HCF tip is submerged in a UV-photosensitive polymer (RI = 1.46), creating three cavities, which will create two observable light interferences, allowing the observation of two FP responses in the spectral response. Two sensors with different HCF lengths were created to compare their sensitivities. After curing, the sensors were calibrated to both parameters in the ranges of 0.0 to 4.0 bar (steps of 1.0 bar) and 22.0 to 30.0 °C (steps of 2.0 °C), respectively. By tracking the peak shifts of the FP, it achieved higher sensitivities for the sensor with the shorter HCF tip (182.30 µm of HCF and 28.56 µm of UV-polymer lengths) of around 31.65 nm/bar and 1.53 nm/°C. On the other side, the sensor with the longer HCF tip (318.56 µm of HCF and with 52.17 µm of UV-polymer lengths) achieved 15.65 nm/bar and 1.02 nm/°C. Regarding the FBGs, they achieved 9.65 and 7.86 pm/°C for the longer and shorter sensor, respectively, while presenting insensitivity to pressure. Therefore, the shorter FP cavity produces the more sensitive sensor because, since its length is shorter and possesses a concave shape, it is more susceptible to external changes. Thus, variations of pressure and temperature could be discriminated by using the matrixial method with the FP and FBG sensitivities, given that the determinant of the coefficient matrix results is -0.31, a non-zero value. The developed sensor has the potential to integrate specific applications, such as LiBs to measure and decouple both parameters.
Rubber vulcanization method for FBG pressure sensors
Authors: Avellar Leandro , Frizera Anselmo , Diaz Camilo , Leal-Junior Arnaldo 
Published: December 2022

Abstract
This paper presents the experimental analysis of the vulcanization process of nitrile rubbers for the diaphragms fabrication used in FBG-based pressure sensors. Tests using diaphragms with different rubber thicknesses (0.5mm, 1.0mm, and 1.5mm), vulcanization temperatures (125°C, 150°C, and 200°C), and vulcanization times (2.5min and 5.0min) were performed to analyse the chemical degradation of diaphragms. Degradation analysis was performed using digital macrography of the diaphragm surfaces and the diaphragms stiffness was analysed by tensile tests. An FBG was embedded in the diaphragm which was vulcanized using the temperature and time which resulted in the lowest rubber degradation, and a compression test was performed. Results of the digital macrography show that diaphragms vulcanized at 125°C presented smaller degradation areas, in which diaphragms with 0.5mm rubbers presented an area degradation mean of 17.5%, whereas 1.0mm rubbers presented 14.5%, and 1.5mm rubbers showed 11.0%. Moreover, greater thickness led to smaller degraded area for the same temperature and vulcanization time. Thus, for the same thickness in the rubber, the higher vulcanization temperature results in a higher material stiffness, where stiffness is directly related to the reduction of cross-links due to the degraded area. Results of the sensitivity test using diaphragms vulcanized at 125°C showed a pressure sensitivity of 11.67kPa/mm and wavelength sensitivity of 456.1pm/mm for 0.5mm rubber thicknesses, 18.04kPa/mm pressure sensitivity, and 112.3pm/mm wavelength sensitivity for 1.0mm rubber thickness and 31.55kPa/mm pressure sensitivity and 913.8pm/mm wavelength sensitivity for 1.5mm rubber thickness. It concludes that the 0.5mm rubber vulcanized diaphragm obtained higher sensitivity when comparing pressure and wavelength.