bluuebunny/crossref_metadata_2025 huggingface dataset:
Wastes to profit: a circular economy approach to value-addition in livestock industries
Authors: Ramirez Jerome , McCabe Bernadette , Jensen Paul D. , Speight Robert , Harrison Mark , van den Berg Lisa , O'Hara Ian
Published: February 2021

The livestock sector is a fundamental part of the modern global economy and provides food, clothing, furnishings, and various other products. So as to ensure its resilience to changes in consumer expectations, cost of production, and environmental sustainability, the sector must shift to a circular economy model. Current strategies to recover value from wastes and low-value co-products from livestock industries yield limited value; hence, new technologies are required to upgrade wastes and co-products, and generate high-value products that can feed into the livestock value chain. Anaerobic digestion can convert high organic-content waste to biogas for energy and a stable nutrient-rich digestate that can be used as fertiliser. Microbial technologies can transform wastes to produce nutritionally advanced feeds. New materials from waste can also be produced for livestock industry-specific applications. While aiming to add commercial value, the successful implementation of these technologies will also address the environmental and productivity issues that are increasingly valued by producers and consumers.
Does exercise therapy improve patient-reported outcomes in rheumatoid arthritis? A systematic review and meta-analysis for the update of the 2020 JCR guidelines for the management of rheumatoid arthritis
Authors: Sobue Yasumori , Kojima Toshihisa , Ito Hiromu , Nishida Keiichiro , Matsushita Isao , Kaneko Yuko , Kishimoto Mitsumasa , Kohno Masataka , Sugihara Takahiko , Seto Yohei , Tanaka Eiichi , Nakayama Takeo , Hirata Shintaro , Murashima Atsuko , Morinobu Akio , Mori Masaaki , Kojima Masayo , Kawahito Yutaka , Harigai Masayoshi
Published: February 2021

Objectives

This study aimed to evaluate the impact of exercise therapy on patient-reported outcomes (PROs) in rheumatoid arthritis (RA) as part of the process of updating the 2020 Japanese guidelines for the management of RA according to the Grading of Recommendations, Assessment, Development, and Evaluation system.

Methods

We searched PubMed, Japana Centra Revuo Medicina Web, and the Cochrane Library (from 2009 to 2018) to identify articles that evaluated PROs of exercise therapy and RA disease activity.

Results

A total of 662 articles were identified, including nine RCTs, and meta-analyses were performed on six RCTs on systemic exercise therapy and three RCTs on upper extremity exercise therapy. Analyzed exercise therapies were diverse, differing in target population, intervention method, and duration. Significant improvements were observed in the Health Assessment Questionnaire Disability Index (mean difference −0.35, 95% confidence interval (CI): −0.60 to −0.10), pain (standardized mean difference −2.04, 95% CI: −3.77 to −0.32), and SF-36. For upper extremity exercise therapy, significant improvements in PROs (Disabilities of the Arm, Shoulder, and Hand Questionnaire, Michigan Hand Outcome Questionnaire) were observed.

Conclusion

Exercise therapy in RA treatment improves patient subjective assessment of pain, physical function, and quality of life.
The heat distribution in a logarithm potential
Authors: Paraguassú Pedro V , Morgado Welles A M
Published: February 2021

All statistical information about heat can be obtained with the probability distribution of the heat functional. This paper derives analytically the expression for the distribution of the heat, through path integral, for a diffusive system in a logarithm potential. We apply the found distribution to the first passage problem and find unexpected results for the reversibility of the distribution, giving a fluctuation theorem under specific conditions of the strength parameters.
A Novel Method for Parameter Identification of Fuel Cell Equivalent Circuit Model
Authors: Jin Zhihan , Su Jianhui , Shi Yong , Wang Haining , Chen Yonghui
Published: February 2021

In order to monitor the running state of fuel cell and prolong its service life, fault diagnosis technology has been widely researched. The fuel cell equivalent circuit model (ECM) can easily characterize the water content and membrane drying of the cells which has attracted the attention of scholars. Usually ECM is obtained by electrochemical impedance spectroscopy (EIS), and uses an electronic load for impedance excitation test, then achieves parameter identification through algorithms for fault diagnosis. This paper proposes a novel fuel cell ECM model parameter identification method by constructing a new combined network that the fuel cell ECM is included. It doesn’t require an electronic load to provide an excitation, meanwhile it relies on the DC/DC converter’s input voltage and inductor current, without voltage and current sensors on the fuel cell side. It uses the least square method to identify this new combined network’s parameter. This method reduces the cost of system components and achieves a good test performance.
Analysis Of Typical Power Grid Blackout Accidents And Suggestions For Countermeasures
Authors: Yi ZHANG , Feng ZHANG , Youchun LI , Lv TANG , Xuehu PENG , Jianguo MO
Published: February 2021

The prevention and control of power grid blackout has become an important research content of the modern power industry and government departments. This paper collects and compares 160 influential international large-area blackouts since 1960, summarizes and analyzes the main causes, common problems and developing Process. Combined with the operation of China's power grid, the main risk sources of large-scale blackouts and the recovery process are summarized. Based on the lessons of international blackout accidents, some specific suggestions and countermeasures are put forward from four aspects, such as strengthening risk management and operation control of large power grid, which can provide useful reference for the safe operation of large power grids above provincial level.
PSCAD-MATLAB Coupled Simulation Method for Power Flow Optimization using Continuous Reactive Power Controllable Device
Authors: Yang Fan , Chen Kai , Qian Shaofeng , Zhan JiangYang , Yu Rui , Song Pan
Published: February 2021

With the integration of distributed generation (DG), micro-grids and are becoming attractive. Power flow studies are very important in the planning or expansion of power systems. The paper proposed a novel method that incorporates MATLAB and PSCAD to study the optimal control of the reactive control algorithm to reduce the power loss in the transmission lines. The proposed strategy is easy to implement and effective in solving the dynamic power flow problems. The results can apply to control the continuous reactive power controllable device and show that the power loss can be greatly reduced.
Research on commutation identity between matrix converter and three-level inverter
Authors: Cai Wei , Sun Junzhong , Wang Zongliang
Published: February 2021

The commutation strategy is the important content of matrix converter industrial application, for it not only affects the converter safe operation, but also is closely related to the input and output performance. In this paper, the matrix converter and the three-level inverter are compared on the perspective of three-level, the relationship between them is studied, and the logical correspondence of switch tubes in two topologies is established. By analyzing the switching sequence of the three-level inverter and equivalent the clamping diode, the two-step voltage-controlled commutation strategy is obtained, which proves the equivalence between the matrix converter and three-level inverter.
Analysis of Condensation Problem in High Voltage Switchgear and Design of Anti-condensation System
Authors: Jinlei Hu , Yangyang Li , Junju Lai , Wei Wang , Fan Yang , Yuhang Liu , Yao Zhao
Published: February 2021

The southern region is hot, rainy and humid, and the switchgear is prone to moisture and condensation during long-term operation in this environment, causing partial discharge and other failures. To solve the problem that the switchgear is prone to condensation, this paper studies the conditions for the condensation phenomenon and analyses the condensation temperature calculation curve based on the air temperature and relative humidity in the cabinet. Then a three-dimensional model of the switchgear was established, and the thermal-electric coupling finite element simulation was performed to obtain the spatial temperature distribution of the switchgear under long-term operation and different humidity states. The simulation results are combined with the condensation temperature calculation curve to study the condensation situation of the switchgear under different conditions and the parts prone to condensation. Finally, according to the analysis results, a moisture-proof and anti-condensation control and early-warning system based on optical fiber temperature and humidity sensor is provided to detect the data in the cabinet and conduct comprehensive research and judgment, which provides theoretical basis for anti-condensation and intelligent operation and maintenance of switch cabinet.
Adsorption behavior of Cu-doped ZIF-67 for decomposition gases of organic insulator: A first-principles study
Authors: Li Song , Wei Xiao , Zhu Shiping , Zhou Qu , Gui Yingang
Published: February 2021

In order to detect the decomposition gas of organic insulator in gas insulated switchgear, Cu doped ZIF-67 material was proposed. In this paper, the gas adsorption process was analyzed by the first principle. The calculation indexes include density of States (DOS), adsorption energy (Eads
), charge transfer quantity (Qt
), Charge density difference (CDD), electron localization function (ELF), the highest occupied molecular orbitals (HOMO) and the lowest unoccupied molecular orbital (LUMO). The results show that the adsorption capacity of Cu-ZIF-67 for CO and CO2 is better than that of CF4 in the single gas adsorption calculation. The adsorption energies of three single gases are -1.306eV, -1.597eV and -0.991eV, respectively. Therefore, this study provides excellent gas sensing materials and scientific theoretical calculation for selective detection and gas adsorption of decomposition gas.
IGBT Failure mechanism and boundary analysis under large current and high temperature turn-off
Authors: Ma Xiao , Huang Yongle , Luo Yifei
Published: February 2021

Considering overload working conditions in electromagnetic emission, the paper presents a simulation of IGBT turn-off under large current and high temperature. Numerous simulation result is received under a specific test circuit. Boundary conditions for temperature, current and starry inductance are obtained under a set of temperature criterion. Further analysis proves that after temperature reaches the criterion, high current density path swiftly extends from local area to a vertical current path throughout the cells. This method for IGBT theoretical boundary is useful for similar projects or working conditions.
STFT Analysis of Broadband Oscillation in VSC-HVDC Connected to Offshore Wind Farms
Authors: Bo Xin , Wang Linyuan , Gao Lei , Zhang Huiyuan
Published: February 2021

The transmission technology of offshore windfarms (OWFs) through VSC-HVDC system is developing rapidly. The impact factor of broadband oscillation is complex, it often occurs in VSC-HVDC and direct drive permanent magnet synchronous generator (DDPMSG). In this paper, based on short time fourier transform (STFT), factors that cause broadband oscillation are studied. Firstly, the primary structure of DDPMSG and VSC-HVDC is established. Then the correctness of small signal method (SSM) is verified. Based on eigenvalue analysis, instability caused by controlling parameter is analysed. Finally, time-frequency characteristic of oscillation waveforms in PSCAD is extracted using STFT, asynchronous characteristics of broadband oscillation is verified. It is of guiding significance, for the developing technology of offshore wind farm integrated into grid through VSC-HVDC system.
Research on the wettability of pulse electrochemical machining GCr12 substrates
Authors: Tian Kun , Xu Jinkai , Ren Wanfei , Sun Xiaoqing , Liu Zheming , Yu Huadong
Published: February 2021

Based on mold steel (GCr12), the relationship between pulse electrochemical machining (PECM) parameters and surface for wetting characteristics was explored. The groove structure with the depth of 0.5mm has been machined on the surface of the steel casting GCr12 by impulse electrochemical machine. Under the best processing parameters, the hydrophobic angle can reach 161.8°. The microstructure, elementary composition, and wettability of the sample were characterized and analyzed by scanning electron microscope (SEM), ultra-depth-of-field microscope, EDS energy spectrum, and contact angle measuring instrument. Single factor experiments are used to explore the influence of pulse electrochemical machining voltage and pulse time on the surface wettability of mold steel (GCr12).
Research on 220kV Substation Main Electrical Connection Optimization Based on Life Cycle Cost Theory
Authors: Zeng Wenhui , Liu Xiaoyu , Wang Hanyu , Li Chunmei , Sun Xu , Zhang Zhirong
Published: February 2021

As a key link of power transmission, substation main wiring plays an important role in improving the reliability of power supply in the grid. At present, the design of substation main wiring mainly is made with reference to the typical design schemes. However, due to the continuous development of load and the reliability requirements, the traditional wiring scheme may not fully meet the actual operation requirements. In response to this problem, a new main wiring idea is proposed, 3/2 circuit breaker wiring is added to the conventional double bus wiring scheme to form a mixed wiring scheme. The reliability of each scheme is calculated and analyzed. A certain 220kV substation with heavy load in Chengdu is taken as an example, the loss of social output value is considered, the comprehensive economy of the whole life cycle of the substation construction is calculated and compared, and finally the conclusion is drawn that the reliability and economy of the proposed scheme are the best.
Research on hot spot temperature monitoring technology of transformer winding
Authors: Jia Danping , Huangfu Liying
Published: February 2021

A temperature monitoring system based on fiber grating is designed to realize real-time measurement of the hot spot temperature of transformer windings. This paper introduces the principle of fiber grating temperature measurement, and use the Maxwell and Fluent modules in ANSYS to simulate and analyze the electromagnetic field-fluid field-temperature field of the transformer to obtain specific information about hot spots so that the fiber grating can be placed reasonably. Through the fiber grating wavelength demodulation system based on volume phase grating, the center wavelength value of the grating is obtained, and the quantitative relationship between the center wavelength and temperature is found, which proves the feasibility of the system.
An Improved Varied Virtual-space-vector Modulation for Neutral-point-clamped Three-level Inverter
Authors: Zhou Guanqing , Zhang Guorong , Wang Chunpeng , Gao Kai
Published: February 2021

The problem of neutral-point potential balance is always an inherent problem of three-level inverters. In this paper, an improved varied virtual-space-vector modulation method is proposed to improve the neutral point potential balance capability of three-level inverters. Firstly, the virtual medium vector is redefined, and the distribution coefficient k is introduced to control the amount of charge flowing out of the neutral point. Secondly, based on the principle of compensating the maximum charge in a switching period, the appropriate composite voltage vector is selected to improve the dynamic response of neutral point balance control. The simulation results show that the method can accurately control the neutral point potential balance in the full power factor range, and the dynamic and static performance of this method is excellent.
Research on structure design of thermocouple junction for spacecraft thermal vacuum tests
Authors: Liu Jiabin , Zhang Yu , Wu Bin , Yang Xiaoyuan , Xu Xincheng , Liu Zhe
Published: February 2021

This paper investigates the structure design problem for the thermocouple junction in spacecraft thermal vacuum tests. Due to the different configurations during the tests, the length and the number of thermocouples are always different, which would lead to certain cost. As a result, a novel thermocouple integrated junction structure is developed and the thermocouple wire can be re-used. The experiment demonstrates that the proposed design method can save the spacecraft thermal vacuum test cost and considerably improve the test efficiency.
Summary of Gridding-based Planning Method for Electric Energy Substitution Supporting Network
Authors: Li Yaxin , Yang Jie , Fang Rengcun , Xu Hanping , Yang Ruixi , Zhang Dongyin
Published: February 2021

Electric energy substitution technology is of great significance for optimizing the final energy consumption structure, promoting energy conservation and emission reduction, and preventing air pollution. This paper aims to review the current research status of electric energy substitution technology and related fields, summarize the planning methods of electric energy substitution supporting network, and provide reliable network support for large-scale promotion of electric energy substitution. Firstly, the connotation, strategic significance and characteristics of electric energy substitution technology are summarized, and the basic structure of electric energy substitution technology is proposed. Then, the characteristics of network planning and gridding planning ideas are integrated into the gridding planning framework under the background of electric energy substitution is proposed. Finally, the development challenges of gridding planning methods in the current electric energy substitution background in terms of technology, mechanism and infrastructure are summarized, and looking forward to the development direction of the electric energy replacement supporting network plan under the background of the 14th Five-Year Plan and the new round of power system reform.
Power Loss Investigation of Si-SiC Hybrid Switches in a Modular Multilevel Converter System
Authors: Mao Hua , Jiang Huaping , Hu Jiayu , Qiu Guanqun , Ran Li , Wu Yuping , Qin Han , Yang Minxiang
Published: February 2021

To reduce the power loss in a modular multilevel converter (MMC), hybrid switches with different combinations of Si-IGBT, SiC-MOSFET, Si-FRD and SiC-SBD in parallel or anti-parallel are comparatively investigated. By comparing the power losses in MMC submodule (SM) bridge arm switching devices, one bridge arm of a SM is replaced with a different switch configuration, while the other remains in the conventional Si-IGBT and FRD configuration. Itot
− Esw
and I - V curves are obtained for four switch configurations through SIMETRIX, and brought to SIMULINK simulation over longer time scales to account for the variable switch operating condition. Along with the simulation and experimental results, the loss differences under different switch configurations are verified, obtaining the optimal switch configuration at last, which is instructive for the selection of MMC SM in the future.
Research on power Trade Arrangement and Risk Management in South and Southeast Asia
Authors: Liu Xiang-rui , Liu Shuan-quan , Chen Qing-gui , Zhang Mao-lin , Mou Chun-feng , He Pei-shan
Published: February 2021

In recent years, with the continuous growth of economy in South and Southeast Asia, the demand for energy and electricity is also increasing. In terms of power supply and demand, there are complementarities, among which international power trade can realize the optimal allocation of resources among countries and achieve the goal of mutual benefit and win-win results. Now parts of South Asia, southeast Asia within the scope of power trade between overall is still sporadic, and belongs to the power flow on the basis of bilateral one-way trade, electricity trade amount and scale are small, the current trade arrangements to see also is not very perfect, also can't fully meet the needs of the development of South Asia power trade further in southeast Asia. Therefore, it is necessary to study the power trade arrangement in South Asia and Southeast Asia. At the same time, closely related to trade arrangements is the issue of risk, because many risks are often caused by unreasonable trade arrangements. Due to the differences of power construction status and national level among countries in South Asia and Southeast Asia, there are many risks in carrying out power trade, such as political system, environment and economy. Therefore, this paper studies the risk management of power trade in South Asia and Southeast Asia, in order to clearly understand the risks, and take corresponding countermeasures to solve them timely and properly, so as to realize the ultimate goal of power trade in the sub-region smoothly.
Sensorless control of SMPMSM drive system integrated the differential algebra with the algebraic parameter identification
Authors: Xu Ben , Li Hongmei , Yang Liguo , Wang Xianling , Wang jinyu
Published: February 2021

The differential algebraic sensorless control has the technical features of clear concept and low calculation amount. However, this method is particularly sensitive to motor parameters. Therefore, a differential algebraic sensorless control strategy combined with algebraic parameter identification is proposed and applied to surface mounted permanent magnet synchronous motor (SMPMSM) drive system in this paper. Without the signal injection, the proposed method can promptly and accurately realize the online simultaneous identification of stator resistance and inductance based on the different torque conditions of system, and then the motor parameters used in the differential algebraic sensorless control are updated in time. In addition, the tracking differentiator is designed to accurately obtain the first-order differential of the stator current signal with noises for rotor position estimation. Finally, the effectiveness of the proposed sensorless control method is validated by the simulation results.
Research on Pneumatic Muscle Position Control Based on Adaptive Backstepping Sliding Mode
Authors: Jia Danping , Cao Zhi
Published: February 2021

Aiming at the nonlinearity and uncertainty of pneumatic muscles, an adaptive backstepping sliding mode control method is proposed. Using the three-element model of pneumatic muscles, an adaptive backstepping sliding mode controller for pneumatic muscles is designed, which is proved by Lyapunov theory. For the stability of the system, a simulation test platform is built in MATLAB. The simulation results show that the designed controller has fast convergence speed and strong robustness.
Planning method for charging piles of intelligent networked electric vehicles in consideration of charging safety
Authors: Li Lei , Liu Weidong , Li Dan , Li Xiaohui , Liu Xiaochen , Hou Yucheng , Zhang Yajian , Yang Ting
Published: February 2021

As the number of electric vehicles in cities increases, the charging demand has surged. Optimizing deployment planning of electric vehicle charging piles is of great significance to safe charging. Based on the analysis of the factors affecting the planning of electric vehicle charging piles and the spatial distribution characteristics of electric vehicles, this paper proposes a new planning method for urban intelligent networked electric vehicle charging piles that takes into account the charging safety. Using the point clustering algorithm, the optimal division of the urban electric vehicle service range is calculated, and then the central point selection algorithm is employed to allocate the optimal site. Taking the actual electric vehicle charging pile planning in one of the central cities as the experimental example, and comparing with tow of existing charging pile planning methods, the calculation results show that the method proposed in this paper has better planning effects and obtains more reasonable service regional division, balanced services amount, and shorter charging path distance, thus ensuring the safety of charging pile operation and service capabilities.
A Combined Control Strategy Over Full Speed Range of Synchronous Reluctance Motor Considering Iron Loss
Authors: Yang Yutao , Li Wenjing , Song Liangliang , Shen Chuanwen
Published: February 2021

For the perspective of efficiency optimization and field-weakening speed expansion, the research on the optimal control scheme of SynRM is of great significance. This paper proposes a novel control strategy combined maximum torque per ampere (MTPA) control with maximum efficiency (ME) control, for fast and efficient performance of SynRM considering iron loss. As the speed exceeds the rated speed, maximum torque per voltage (MTPV) control is proposed to realize deep field-weakening. The proposed approach is determined by operating conditions of the motor which avoids the deterioration of dynamic performance due to the switching. In particular, while the working speed is increasing, the control must be able to drive SynRM under the combined MTPA and ME control at first, and then on the MTPV trajectory. In this paper, the current feedback decoupling current control in the SynRM model including the iron loss is developed to compensate the cross-coupling effect for high dynamic control performance. The proposed control strategy has been successfully implemented and verified via MATLAB/Simulink software of a vector control system in changing status.
Evaluation method of trust degree of distribution IoT terminal equipment based on information entropy
Authors: Lingda Kong , Feng Zhai , Yingjie Zhao , Nan Qin , Dashuai Li , Shaotang Cai
Published: February 2021

Power distribution Internet of Things terminal equipment is vulnerable to multiple security threats, such as identity disguise, information theft, data tampering. Traditional security methods cannot resist internal network attacks from compromised terminals. The trust evaluation system is an effective mechanism to protect power distribution IoT terminals from internal attacks. This paper proposes a trust evaluation method based on information entropy for the trust problem of power distribution Internet of Things communication terminal. First, the direct trust value is estimated by the model based on the reputation of exponential distribution, and then the direct trust value is updated by the sliding window and forgetting factor. According to the entropy theory, the uncertainty of the direct trust value is measured, and the indirect trust value is introduced to make up for the inaccuracy of the direct trust judgment, and the judgment accuracy is improved through the comprehensive evaluation of the direct trust value and indirect trust value. Experimental simulations show that the method in this paper can effectively resist switch attacks and collusion attacks. At the same time, the method proposed in this paper can better evaluate malicious and normal terminals than binomial trust management and trust evaluation based on beta distribution.
Optimization and control strategy of MCR reactive power allocation in urban power grid
Authors: Jin Wei , Chen Xuxuan , Li Man , Li Wenfan
Published: February 2021

Aiming at the defects of the traditional reactive power compensation method in the original system of urban power grid, such as large difference in compensation capacity and single form, a configuration optimization strategy based on MCR reactive power compensation device is proposed. The optimal compensation point is evaluated by using the comprehensive degree index of voltage stability, and the reactive power optimization mathematical model of power system is established. The optimal reactive power configuration is obtained by optimizing the parameters of the mathematical model combined with particle swarm optimization algorithm. Finally, the dynamic reactive power compensation for 220KV level regional node system is added, according to the proposed reactive power configuration optimization scheme, to conduct simulation experiments, and the results show that the proposed method is reasonable and effective.
Design of Nonlinear Excitation Controller for Generator Based on Differential Algebra
Authors: Wang Zhongyong , Xu Yingjing
Published: February 2021

With the appropriate transformation to the system model, this paper proposed the nonlinear control strategy for differential algebraic system based on the linear control law. Applying the method to single machine infinite-bus power system, which belongs to a nonlinear differential algebraic model, a nonlinear excitation control law has been designed. Simulation results show that the control law can enhance the stability of the system, also it can improve the regulative precision of generator terminal voltage, make each state trace for their given values rapidly. It manifests that the proposed method can effectively solve the design problem for nonlinear differential algebraic system and it is valuable for application.
Field-circuit Coupled Modeling of a Novel Continuous Reactive Power Controllable Device for Power Flow Optimization
Authors: Liu Weihao , Chen Kai , Tang Jian , Cao Zhangjie , Hong Li , Song Pan
Published: February 2021

The paper proposed a novel method that incorporates MATLAB and FEM simulation to study the dynamic characteristics of the magnetic devices. The semi-physical modeling method is easy to implement and effective in simulating the operation characteristic and speeding up the magnetic device research. The results can further apply to control the continuous reactive power controllable device and optimize the power flow in the power system.
An optimized parameter control method of resonance corrector for improving the output characteristics of singlephase inverter
Authors: Lei Kang , Shao Ying , Zhang Yin Feng , Wang Kongxian
Published: February 2021

According to the principle of internal mode, the resonant corrector is applied to the control system of single-phase inverter, which can effectively improve the output characteristics of the system. Based on the mathematical model, the dc input voltage fluctuation and load change are taken as the uncertain factors affecting the performance of the inverter, and the parameter optimization design of the resonant corrector is carried out based on pole assignment. The simulation results show that compared with the traditional quasi-PR controller, the controller designed with the resonance corrector parameter optimization can better adapt to the continuous large range of voltage fluctuation at the DC input end, and the system has good dynamic performance, waveform stability, and the ability to resist load disturbance.
Lightweight Key Management Scheme for Wireless Communication System of Distribution Network
Authors: Kong Lingda , Zhai Feng , Zhao Yingjie , Yu Liying , Zhou Junhao , Yan Peng , Cai Shaotang
Published: February 2021

Key management is the key to ensuring the information security of the intelligent distribution network. Based on the analysis of the communication characteristics and key management requirements of the intelligent distribution network, this paper proposes a lightweight intelligent distribution network key management scheme DNKMS. According to the storage and computing capabilities of power distribution terminals, electronic distribution stations and power distribution master stations, task distribution is optimized, and the design idea of the scheme and the process of key generation, distribution, update, and destruction are described in detail. The analysis results show that the proposed scheme has less time overhead and higher efficiency, can reduce the communication and calculation load required in key management, and meet the security requirements of key management in smart distribution networks.
Research on Key Technologies of Autonomous Driving Platform
Authors: Yuan Xiaoyu , Liu Hai , Qi Rao
Published: February 2021

With the continuous development of the economy, people's economic level is constantly improving, therefore, the travel demand is also increasing. The increasing demand for travel has brought many problems to transportation, such as travel efficiency, traffic safety, and environmental protection. Autonomous driving technology provides new ideas for solving current traffic problems. Autonomous driving is a hotspot and frontier in the field of artificial intelligence. Autopilot system is a very complex system, which integrates today's automotive electronics technology, sensor technology, computer technology and artificial intelligence technology. It is one of the frontiers and research hotspots of today's automotive technology revolution. The article first analyzes and summarizes three typical auto-driving methods of automobiles, and then analyzes the principles of auto-driving, focusing on the research on key technologies of auto-driving, aiming to design a safe and reliable auto-driving system.
Vision servo positioning control of robot manipulator for distribution line insulation wrapping
Authors: Tang Xuming , Han Xianguo , Zhen Wudong , Zhou Jing , Wu Peng
Published: February 2021

Traditional visual servo control based on location needs to convert two-dimensional information into three-dimensional space information, and the conversion process is subject to many interference factors, leading to large control errors. Aiming at the above problems, the visual servo positioning control of distribution line insulated wrapping robot and manipulator is studied. The position and pose of the manipulator are described and homogeneous transformed so as to calibrate the camera vision system of the manipulator. The image Jacobian matrix is established to realize the visual servo positioning control of the manipulator. Compared with the traditional control method, the experimental verification shows that the control method can reduce the pose error by at least 39.7%, and the control effect is more stable and the reliability is better.
An online optimal energy management strategy for a dual-mode power-split hybrid electric vehicle based on hybrid MPC Algorithm*
Authors: Li Xunming , Wang Weida , Yuan Yi , Li HuanHuan , Guo Lei , Qiu Shi
Published: February 2021

This paper proposed a global on-line optimisation energy management strategy based on the hybrid model predictive control (HMPC) algorithm. First, the non-linear models of a dual-mode power-split hybrid electric vehicle is built. Then, the dual-mode power-split hybrid electric vehicle is considered as a hybrid system which includes continuous and discrete states, and a mixed logical dynamic (MLD) predictive model is built based on hybrid system theory. Thirdly, an HMPC energy management strategy is designed based on the MLD predictive model. The HMPC-based energy management strategy is compared with dynamic programming based and rule-based energy management strategies. The simulation results indicate that the HMPC-based energy management strategy is helpful for real-time control and improving fuel economy. good control performance. Finally, the control performance of the proposed HMPC-based energy management strategy is compared with that of the DP-based energy management strategy and rule- based energy management strategy. The simulation results indicated that the control performance of HMPC can achieve 80.6 % of that of DP.
Rolling Bearing Fault Diagnosis Based on GUI System
Authors: Zhang Yichi , Shu Tao , Liu Chengliang , Ding Rixian
Published: February 2021

Rolling bearing can be used in many complex weapon equipments to reduce friction and improve their productivity. Accordingly, a rolling bearing fault diagnosis and life prediction system interface is made by using the graphical user interface system module of MATLAB so that the theoretical value of the local defect frequency can be calculated based on the possible fault types of the main structure of the rolling bearing. Then the fault category of bearing can be identified by comparing the impact interval frequency of bearing fault extracted by Hilbert transform with the theoretical fault frequency.
The multi-scale channel attention full connection network for edge detection
Authors: Li Meng , Wu Wei
Published: February 2021

Edge detection algorithms based on deep learning have made great progress due to its super feature extraction and presentation ability in recent years. However, existing edge detection algorithms encounter some problems that image features extracted by networks are not sufficient, and the generated edges are fuzzy with large gap compared to the ground truth (GT). To solve the abovementioned problems, we have proposed a multi-scale channel attention full connection network model for edge detection (MAED) in this work. The proposed network consists of three parts: multi-level feature extraction part, multi-scale deep supervise part and fusion part. In addition, by introducing the "attention" mechanism into the networks, underlying features of the input image can be fully extracted and the training convergence speed can be accelerated simultaneously. To evaluate the performance of the proposed algorithm, we conducted a comprehensive study on some commonly-used datasets. The final experimental results demonstrated that our network achieves excellent performance based on both qualitative and quantitative analysis.
Leader-Following Bipartite Formation Control of Multiple Nonholonomic Robot Systems Over Signed Graph
Authors: Liu Yupei , Xie Wenjing , Zhao Yixin , Huang Wei
Published: February 2021

This paper studies the bipartite formation control problem of multiple nonholonomic robot systems over signed graph. To overcome nonholonomic and underactuated control challenges, the hand position output is defined to obtain a linear hand position subsystem. A distributed control law is designed, which uses sliding mode control technology to eliminate the influence of dynamic leader, so that the global index of position formation error converges to an arbitrary small neighborhood of the origin. Then, the zero dynamic equation is computed, and based on it and Lyapunov method, the convergence conditions on controller parameters and on leader’s velocities are derived to guarantee the angle error is bounded and convergent. Finally, a simulation example containing eight robots and one leader is given to demonstrate the effectiveness of the proposed control strategy. In contrast to related results, this paper presents the complete stability analysis and corresponding stability conditions, in addition to the control law and stability of position subsystems.
Design and Application of Automatic Recovery System for Outer Material of Cigarette parcel
Authors: Huang Linqi , Liu Wenfeng , Luo Jiazheng
Published: February 2021

In order to solve the problems of high labor-intensity and low-efficiency in recycling the outer materials of cigarette parcel manually, an automatic recycling system is designed. The system consists of visual recognition system and material grabbing system. After recognizing the type of outer material through the VGG16 network, the visual recognition system will output the corresponding label to make the material grabbing system execute the according process. The material grabbing system adopts rectangular coordinate robot with flexible structure. With transmitting data and signals by PROFINET, each axis of the robot can perform combined actions. In consequence, the system is able to separate and remove materials that are highly overlapped with the cigarette parcel, and send materials to outside for recycling and sorting by conveyor. The results of on-site test showed that the accuracy of the system to identify the material was 95%, the success rate of grabbing reached 96% and the system took an average of 18s to recover materials, the system could fulfil the requirements of real-time and automatic recycling of materials, and provide technical support for improving the automation level of cigarette factory unpacking line.
Test configuration method based on E-dominant NSGA2
Authors: Yun Lin
Published: February 2021

In order to solve the problems of the same target importance and too large solution set in the existing solutions, an E-dominant NSGA2 algorithm is proposed to solve the problem. In this paper, the mathematical model of the problem is established with the optimization objectives of test cost, test quantity and false alarm rate. The testability model under unreliable test condition is established by using Bayesian network. Then the E-dominated NSGA2 algorithm is used to solve the problem. After verification, the algorithm has good performance and practical value.
Model design and gait planning of hexapod climbing robot
Authors: Cai Zhongbin , Gao Yong , Wei Wu , Gao Tianxiao , Xie Zhijian
Published: February 2021

In this paper, we design a hexapod climbing robot and propose a cross-plane transition gait algorithm to solve the problem that the general walking robot can't perform the work at high altitude and can't realize the autonomous transition between multiple planes. Firstly, we build a simulation control system based on MATLAB and V-REP for algorithm analysis and motion verification. Meanwhile, virtual connection technology is used to design virtual suction sensor to simulate the real adhesion mechanisms. Then, the single-plane walking gait algorithm is designed based on the SS-Shaped interpolation function, which effectively avoid the wear of the adhesion mechanisms. The transition algorithm based on workspace constraints is designed to greatly improve the adaptability of robots in complex environments. Finally, the simulation of rhythmic gait motion and ground-slope transitional motion verify the effectiveness of the gait planning method.
Design and curative effect of Embedded Intelligent External Neural Pacemaker for Prostate
Authors: Pang Wenyang , Ge Chenhao , Sun Lili , Zhong Yuanchang
Published: February 2021

Aiming at the problem of extracorporeal treatment of prostate diseases, an embedded intelligent prostate extracorporeal nerve pacemaker has been designed using smart chips through the principle of digital signal generator. The treatment effect has been tested through the experiment on 22 related patients in the urology department. Experimental results show that the device can accurately simulate a variety of neural signals and the frequency and amplitude of which are adjustable. The performance of the device can be considered as stable and reliable. In particular, it can generate bioelectrical signals which are similar to the basic electrical rhythm of a normal human prostate, so that the bioelectrical activity of prostate pacemaker can return to normal rhythm. The treatment has achieved good auxiliary treatment effects. The device provides a new solution for the auxiliary treatment of prostate diseases.
Computer aided design of amorphous alloy permanent magnet motor
Authors: Chen Ping , Qi Tingting , Zuo Ning , Wang Zexuan
Published: February 2021

Amorphous alloy is a kind of double green soft magnetic material with high saturation magnetic induction, low coerce, low loss, high stability and other excellent properties. Instead of cold rolled silicon steel sheet, it can reduce the loss and improve the efficiency of the motor to a great extent. Combined with the characteristics of amorphous alloy and based on the design theory of permanent magnet motor, this paper uses the MATLAB software to write the electromagnetic design program of amorphous alloy permanent magnet synchronous motor, which has the characteristics of visual parameter input, rapid electromagnetic calculation, and convenient man-machine interaction. An example is given to verify the reliability of the program.
Steady-State Analysis Based on Space Vector Model of Self-Excited Induction Generators
Authors: Li Haitao , Peng Xuehu , Chen Lili , Zheng Xiaodan
Published: February 2021

In order to attain more optimization for the procedure of transient and steady-state operation performance analysis and evaluation of self-excited induction generators (SEIGs), the paper converts the state-space transient mathematic model with real domain into the space vector transient model with complex domain based on the same two-phase stationary reference frame, described by which the physical systems can apply extendedly the holistic analysis approach based on Lyapunov stability theory proposed in real domain. Through equivalent analysis, the extended form of the steady-state conditions and its mathematic description into the complex domain is obtained, that is, the extended quasi limit cycle and the steady-state operating points. The analytic calculation for the extended steady-state condition provides successively the analytic solutions of exciting capacitance, stator frequency, as well as the extended steady state conditions under given rotor speed and magnetizing inductance. The practical calculation example verifies correctness and effectiveness of the approach and the analytic solution of the extended steady-state condition, with engineering reference values.
Research on Coupled field of the transformer vibration influenced by DC bias using Fast-ICA method
Authors: Tian Hao , Liu Xingmou
Published: February 2021

This paper proposes a multi-physical coupling model, which is an association of mathematical models of transformer core vibration analysis. The purpose of this model is transformer vibration analysis. Under different DC biases, the vibration process of the transformer core is simulated and analyzed by using the primary voltage as the excitation condition. The Fast-ICA algorithm is proposed, which evidences that the vibration when the transformer is no-load is the core vibration. The experimental results show that the Fast-ICA algorithm is used to analyze the transformer vibration signal under different DC bias conditions and obtain better results, which provides a new method for studying the transformer DC bias vibration.
Structure Optimization of Permanent Magnet Linear Ejection Motor with Moving Armature
Authors: Xie Guanglei , Wu Jun , He Yongxiang
Published: February 2021

In order to meet the needs of the battlefield, a double-sided moving armature permanent magnet linear ejection motor with high maneuverability is proposed. The structure of the permanent magnet linear ejection motor with moving armature is optimized. By designing the self-alignment guide structure, the air gap can automatically tend to be symmetrical and the normal force caused by the asymmetry of the actuator can be weakened. The eddy current resistance in the process of launch can be effectively reduced by replacing supporting frame materials and applying stiffeners. In addition, the braking effect of the brake segment can be improved and the impact force can be reduced by changing the brake structure to hydraulic damping brake.
A Lightweight Wireless Charging method for Unmanned Aerial Vehicles
Authors: Zhai Xuefeng , Wang Hongxing , Li Jun , Huang Zheng , Gao Ruozhong
Published: February 2021

Recently, more and more unmanned aerial vehicles (UAVs) have been used in industry, public services and commercial fields. However, the UAV is generally limited by the battery capacity, and the operation radius is greatly limited. In this paper, to increase the flight time of the UAV, the recharging station by using wireless power transfer (WPT) technology is proposed. A new receiver magnetic coupler is given, the receiver coil is wound around the hollow ferrite core, and the proposed structure provides many benefits: 1) first, there is a large magnetic flux captured surface, which can improve the mutual coupling between the primary side and secondary side. 2) Second, own to the hollow ferrite core, the receiver side is light, which has little effect on the weight bearing of UAV. 3) Third, it is easy to be installed on the UAV, since the receiving coil is compact. 4) Moreover, the proposed WPT system provides enough anti misalignment capability for UAV.