bluuebunny/crossref_metadata_2025 huggingface dataset:
A subregion-based survival prediction framework for GBM via multi-sequence MRI space optimization and clustering-based feature bundling and construction
Authors: Chen Hao , Liu Yang , Pan Xiaoying , Yang Qing , Qiang Yongqian , Qi X Sharon
Published: May 2023

Aiming at accurate survival prediction of Glioblastoma (GBM) patients following radiation therapy, we developed a subregion-based survival prediction framework via a novel feature construction method on multi-sequence MRIs. The proposed method consists of two main steps: (1) a feature space optimization algorithm to determine the most appropriate matching relation derived between multi-sequence MRIs and tumor subregions, for using multimodal image data more reasonable; (2) a clustering-based feature bundling and construction algorithm to compress the high-dimensional extracted radiomic features and construct a smaller but effective set of features, for accurate prediction model construction. For each tumor subregion, a total of 680 radiomic features were extracted from one MRI sequence using Pyradiomics. Additional 71 geometric features and clinical information were collected resulting in an extreme high-dimensional feature space of 8231 to train and evaluate the survival prediction at 1 year, and the more challenging overall survival prediction. The framework was developed based on 98 GBM patients from the BraTS 2020 dataset under five-fold cross-validation, and tested on an external cohort of 19 GBM patients randomly selected from the same dataset. Finally, we identified the best matching relationship between each subregion and its corresponding MRI sequence, a subset of 235 features (out of 8231 features) were generated by the proposed feature bundling and construction framework. The subregion-based survival prediction framework achieved AUCs of 0.998 and 0.983 on the training and independent test cohort respectively for 1 year survival prediction, compared to AUCs of 0.940 and 0.923 for survival prediction using the 8231 initial extracted features for training and validation cohorts respectively. Finally, we further constructed an effective stacking structure ensemble regressor to predict the overall survival with the C-index of 0.872. The proposed subregion-based survival prediction framework allow us to better stratified patients towards personalized treatment of GBM.
Hemodynamic monitoring in the human temporalis muscle using near-infrared spectroscopy
Authors: Rashid Anas , Roatta Silvestro
Published: May 2023

Objective. Altered temporal muscle perfusion is implicated in several painful disorders afflicting orofacial and head regions, including temporomandibular joint dysfunctions, bruxism, and headache. Knowledge about the regulation of blood supply to the temporalis muscle is limited, due to methodological difficulties. The study aimed to test the feasibility of near-infrared spectroscopy (NIRS) monitoring of the human temporal muscle. Approach. Twenty-four healthy subjects were monitored with a 2-channel NIRS: a muscle probe placed over the temporal muscle and a brain probe placed on the forehead. A series of teeth clenching at 25, 50, and 75% of maximum voluntary contraction for 20 s and hyperventilation for 90 s at 20 mmHg of end-tidal CO2 were performed, to elicit hemodynamic changes in muscle and brain, respectively. Main results. In twenty responsive subjects, NIRS signals from both probes were consistently different during both tasks. The absolute change in tissue oxygenation index (ΔTOI) as detected by muscle and brain probes was −9.40 ± 12.28 and 0.29 ± 1.54% during teeth clenching (p < 0.01) at 50% maximum voluntary contraction, while −1.03 ± 2.70 and −5.11 ± 3.81% during hyperventilation (p < 0.01), respectively. Significance. Distinct response patterns were observed from the temporal muscle and prefrontal cortex which proves that this technique is adequate to monitor tissue oxygenation and hemodynamic changes in human temporal muscle. Noninvasive and reliable monitoring of hemodynamics in this muscle will help to extend basic and clinical investigations about the peculiar control of blood flow in head muscles.
Terahertz wideband modulator devices using phase change material switchable frequency selective surfaces
Authors: Barzegar-Parizi Saeedeh , Ebrahimi Amir , Ghorbani Kamran
Published: May 2023

Phase change materials (PCMs) such as temperature sensitive materials have received considerable attention in the optics and THz regime because of the reversable switching of their electromagnetic properties. In this paper, wideband switchable absorbers based on vanadium dioxide (VO2) have been designed and simulated at the terahertz (THz) regime. The switching functionality is enabled by the phase change of the VO2 layer from a metal state to an insulator through the temperature transition. The phase change temperature is 68 °C. The first designed absorber shows a wideband absorption spectrum (fractional bandwidth of 92.3%) with absorptivity above 90% in the metal state, where conductivity of the VO2 layer is 200000 S m−1, whereas the absorptivity is less than 3% in the insulator state, when the conductivity of the VO2 reaches 200 S m−1. An equivalent circuit model-based analysis is presented for metal state. Based on the results, the extinction ration is less than –11 dB with 0.9 modulation depth for a wide frequency range from 2.2 to 5.87 THz. This makes the proposed structure a suitable candidate for broadband modulation at THz frequencies. An ultra-broadband absorption spectrum is achieved in the second design utilizing the stacked structure of two VO2 layers in metal state, where each layer acts as a resonator. This absorber prototype offers more than 90% absorptivity within 1.2–6.1 THz corresponding to a relative bandwidth of 135%.
Updated constraints on amplitude and tilt of the tensor primordial spectrum
Authors: Galloni Giacomo , Bartolo Nicola , Matarrese Sabino , Migliaccio Marina , Ricciardone Angelo , Vittorio Nicola
Published: May 2023

We have taken a comprehensive approach to update the limits on the tensor-to-scalar ratio (r) and the tensor spectral index (nt
), using 10 datasets from the BICEP/Keck Array 2015 and 2018, Planck releases 3 and 4, and LIGO-Virgo-KAGRA Collaboration. By fitting the complete ΛCDM+r+nt
model with two different approaches for the tensor sector, we have not only established which method is the most reliable, but have also achieved the strongest constraint on the tensor-to-scalar ratio in current literature: r < 0.028 and -1.37 < nt
< 0.42 at 95% confidence level. Furthermore, our examination of the common signal detected by the NANOGrav Collaboration further confirms that a simple power-law cannot reconcile the constraints from different datasets if the NANOGrav detection is due to a primordial inflationary gravitational wave background, as previously shown in the literature.
SEEGAtlas: A framework for the identification and classification of depth electrodes using clinical images
Authors: Zelmann Rina , Frauscher Birgit , Aro Renzo Phellan , Gueziri Houssem-Eddine , Collins D Louis
Published: May 2023

Objective. Accurate localization, classification, and visualization of intracranial electrodes are fundamental for analyzing intracranial electrographic recordings. While manual contact localization is the most common approach, it is time-consuming, prone to errors, and is particularly challenging and subjective in low quality images, which are common in clinical practice. Automatically locating and interactively visualizing where each of the 100–200 individual contacts records in the brain is essential for understanding the neural origins of intracranial EEG. Approach. We introduced the SEEGAtlas plugin for the IBIS system, an open-source software platform for image-guided neurosurgery and multi-modal image visualization. SEEGAtlas extends IBIS functionalities to semi-automatically locate depth-electrode contact coordinates and automatically label the tissue type and anatomical region in which each contact is located. To illustrate the capabilities of SEEGAtlas and to validate the algorithms, clinical magnetic resonance images (MRIs) before and after electrode implantation of ten patients with depth electrodes implanted to localize the origin of their epileptic seizures were analyzed. Main Results. Visually identified contact coordinates were compared with the coordinates obtained by SEEGAtlas, resulting in a median difference of 1.4 mm. The agreement was lower for MRIs with weak susceptibility artifacts than for high-quality images. The tissue type was classified with 86% agreement with visual inspection. The anatomical region was classified as having a median agreement across patients of 82%. Significance. The SEEGAtlas plugin is user-friendly and enables accurate localization and anatomical labeling of individual contacts along implanted electrodes, together with powerful visualization tools. Employing the open-source SEEGAtlas results in accurate analysis of the recorded intracranial electroencephalography (EEG), even when only suboptimal clinical imaging is available. A better understanding of the cortical origin of intracranial EEG would help improve clinical interpretation and answer fundamental questions of human neuroscience.
Complexity and quenches in models with three and four spin interactions
Authors: Gautam Mamta , Jaiswal Nitesh , Gill Ankit , Sarkar Tapobrata
Published: May 2023

We study information theoretic quantities in models with three and four spin interactions. These models show distinctive characteristics compared to their nearest neighbour (NN) counterparts. Here, we quantify these in terms of the Nielsen complexity (NC) in static and quench scenarios, the Fubini–Study complexity (FSC), and the entanglement entropy (EE). The models that we study have a rich phase structure, and we show how the difference in the nature of phase transitions in these, compared to ones with NN interactions, result in different behaviour of information theoretic quantities, from ones known in the literature. For example, the derivative of the NC does not diverge but shows a discontinuity near continuous phase transitions, and the FSC may be regular and continuous across such transitions. We also study multiple quench scenarios in these models and contrast these with quenches in the transverse XY model. The EE shows a novel discontinuity both at first and second order quantum phase transitions.
Study on the Coupling System of Building Flexible Energy and Energy Storage on Power Grid Operation Performance
Authors: Bian Jiayu , Wang Yong , Zhang Zhiyu , Du Wenhan , He Yahui , Chen Weiwei
Published: May 2023

The flexible building energy storage coupling dispatching framework and optimal dispatching model have been established in this paper by using the multi-levels network dispatching analysis method of the grid system. It would include solving the optimization model with the objective function having the minimum standard deviation and the constraint conditions of charging and discharging power and capacity. Second, a simulation analysis who used an example is implemented based on the typical daily load of a Tianjin district. The findings indicate that: energy storage, construction, and flexible energy use The joint optimization’s respective standard deviations are 1.40, 1.59, and 1.24. The system’s power storage, peak-clipping, valley-filling, and other features have a greater impact than the flexible energy use of a standard structure. The building’s flexible energy use has a good peak shaving effect, which can compensate for the problems caused by the general battery energy storage system’s power and capacity limitations during the generation capacity period. In addition, the battery energy storage system can use the valley time to charge, resolving issues with valley filling optimization and the lack of flexible energy use in buildings. From this, it can be seen that the power storage system and the building’s flexible energy use jointly regulate the overall energy use performance of the structure, which not only achieves good peak load cutting and valley filling effect but also controls other issues such as frequent load fluctuations, large load peak valley difference, and other issues, ultimately leading to high energy utilization in China.
Multi-objective combined dispatching optimization of pumped storage and thermal power
Authors: Xiong Zhi , Chen Feng , Guo Hengyuan , Ren Xiao , Zhang Jun , Wang Bo
Published: May 2023

To realize precise and stable power grid dispatching, it is urgent to realize the combined scheduling of Pumped Storage and Thermal Power (PSTP). Considering some factors in the power system, a multi-objective combined optimization model of PSTP is proposed in this paper. Then, this paper proposes an improved multi-objective optimization algorithm base on deep reinforcement learning to solve the above model. Finally, this paper analyzes the advantages and disadvantages of the proposed multi-objective optimization model and finds that the model proposed in this paper sacrifices certain economic benefits but can reduce the system’s fluctuation and improve the power system’s reliability.
Study of Source Network Load and Storage Strategies and Models under Renewable Energy Access
Authors: Chen Hao , Liu Chao yang , Wang Bin bin , liang Yan , Wang Yong Li , Xu Miao miao , Li Yi
Published: May 2023

This paper briefly analyzed the operation mechanism and construction strategy of source grid load storage under the access of renewable energy, and discussed the method of constructing the source-grid-load-storage model under the access of renewable energy. The results of the study show that an economic efficiency of active distribution network operation can be improved by the coordinated optimisation of source network load storage.
Correlation Study Between Cooling Load and Temperature Sensitivity Considering the Cumulative Effect of Temperature
Authors: Ou Rui , Jiang Wen , Zhou Yuqing , Tang Wenzuo , Zhang Yi , He Kai
Published: May 2023

To study the correlation between cooling load and air temperature, this paper uses the maximum load comparison method to calculate the cooling load based on the actual load data of the power grid, and uses the temperature correction model to correct the daily maximum temperature, and then establishes a high-order regression model of cooling load and corrected air temperature. The method is applied to the sensitivity analysis of cooling load and air temperature in the Chongqing power grid and sub-regions, and the corresponding change law is obtained, which provides an important reference basis for the production and dispatch, optimal operation, and marketing of the power grid.
Low Carbon Optimal Scheduling of Integrated Energy Systems Based on Carbon Capture Devices
Authors: Wei Siming , Dai Renjie , Xu Jianwei , Li Tianyu
Published: May 2023

Carbon pollution has gradually become a serious environmental problem in recent years. The low-carbon optimization dispatch of the Integrated Energy Systems (IES) can realize the complementary and energy-use substitution of multiple energy sources and solve the problem of high carbon emission. In this paper, we first construct a system model and a carbon emission model. Then, we introduce carbon capture equipment into the system and construct a system optimization model with equipment constraints for each unit. Finally, we solve the proposed model with a complex solver in Matlab to verify the accuracy of the proposed model and the effectiveness of the method. The results show that the strategy can effectively reduce the carbon emissions of the IES.
Effective Water Injection Development Test for Rolling Outward Expansion of Low-grade Reservoir
Authors: Xu Hongyan
Published: May 2023

The development of ultra-low permeability reservoirs in the oilfield mainly involves a large proportion of ultra-low permeability and it is difficult to recover reserves because of scattered distribution, low reserve abundance, poor reservoir physical property, and great development difficulty as well as low production intensity, rapid production decline, and low stable production of oil wells. In order to speed up the development of undeveloped reserves and explore the effective technical approach to solve problems in low permeability and difficulty in recovering reservoirs, we carried out the effective water injection development test in the B1 test area. In this paper, in-depth research has been carried out in reservoir geological understanding, development well pattern design optimization, and advanced water injection technology research. Finally, a set of effective production technologies for low abundance reserves in complex geological conditions are formed, effective production in B1 Block that was hard to recover reserves is realized, the drilling success rate is improved greatly, and well pattern design optimization is achieved, advanced water injection efficient development technologies for low abundance reserves blocks are also developed. The demand for rolling production can be gradually extended to other oilfields, which has certain reference significance for the development practice of peripheral oilfields and similar small complex fault block oilfields.
Energy Optimal Scheduling Method of Microgrid with Wind and Solar Storage Based on Demand Response
Authors: Huang Jing , Wu Kui
Published: May 2023

In the operation of a microgrid with wind and light storage, energy dispatching will directly affect its operating cost, which is a core technology of microgrid operation. This paper designs an energy optimization method for a microgrid with wind and solar storage based on demand response to realizing more scientific micro-power energy scheduling. Considering the wind-solar storage microgrid’s lowest demand response cost and other comprehensive costs, an energy-optimal scheduling model of the wind-solar storage microgrid is constructed. The model sets the constraints of energy storage devices and ties line transmission power and power balance. A model-solving algorithm based on an improved particle swarm optimization algorithm is designed to realize the optimal energy scheduling of wind and solar storage microgrids. The experimental results show that the cost of microgrid operation has decreased in winter and summer after the optimal scheduling is implemented using the design method, and an excellent economic operation effect has been achieved.
Optimal Dispatching Method of Integrated Energy System of Electrothermal Interconnection Based on Energy Flow
Authors: Qian Kejun , Liu Yi , Li Yafei
Published: May 2023

Aiming at the problem that the total amount of coal consumption and the abandoned wind is too high in the actual operation of the current integrated energy system of electric heating and interconnection, this paper studies the design of the optimal dispatching method of the system from the angle of energy flow. The potential energy dissipation rate of the heat source, heat exchanger, heat pipe network, and other structures in the system is described in mathematical form, and a complete system energy flow model is constructed by combining them. On this basis, the heat load of system users is analyzed and predicted from the angle of energy flow. Finally, the system is divided into power and gas grid variables, optimized to realize distributed multi-objective optimal scheduling. By comparing the operation of the system before and after the optimal scheduling, it is found that the total coal consumption and the total abandoned wind during the system operation are reduced after the optimal scheduling, which proves that the optimal scheduling method has a very high practical application value.
Performance Analysis of Integrated Navigation of New Energy vehicle based on GPS+BDS-3 PPP/INS/ODO in complex Transmission Line Environment
Authors: Zhang Hui , Zhao Jian , Yu Jiangshun , Yu Rong , Liu Wei , Du Hao , Hu Wei , Liu Dandan
Published: May 2023

In a complex environment, the single navigation and positioning method has problems of poor accuracy, reliability, and integrity. This paper proposes a PPP/INS/ODO integrated navigation scheme of GPS+BDS-3. Using the GPS+BDS-3 dual system, the non-ionization combined PPP model is derived, the PPP/INS/ODO combined model is further given, and the processing strategy of time asynchrony and lever arm error is analyzed. Combining the odometer speed measurement information and non-integrity constraint information, it improves the positioning performance of integrated navigation to a certain extent. In the state of GPS+BDS-3 non-ionization combination, PPP and PPP/INS/ODO integrated navigation are analyzed respectively using the simulated dynamic, and new energy measured data. Through the experiment, it can be concluded that the positioning accuracy of the combination of GPS and Beidou 3 is higher than that of a single system to some extent. The PPP/INS/ODO integrated system can provide technical support for new energy vehicle navigation in complex environments with RMS better than 1m.
Research on Power Transmission Tower Planning Method Based on Real Terrain and Surface Feature
Authors: Li Yigang , Fang Zhenggang , Huang Qinghua , Zhang Baodong , Zhao Yong
Published: May 2023

With the rapid development of power grid construction in China, the engineering construction conditions of overhead lines have changed. Further research is needed on the combination scheme of general design technical conditions of lines, tower planning, and design, etc., to meet the application requirements of the actual line projects in China for the general design of transmission line towers. This research adopts the pole and tower planning method that conforms to the real terrain and terrain conditions and considers the actual constraint information, such as the terrain, crossing trees, power lines, and railways, to carry out the planning and design of transmission line poles and towers.
Strain Monitoring of Overhead Transmission Line Based on Brillouin Scattering
Authors: Ouyang Xudong , Zou Xiaoming , Chen Liguang , Wei Zhixiong , Yang Liuhui
Published: May 2023

The change in the optical fiber state and the status of transmission line often leads to the change of strain in its composite optical fiber. This paper attempts to use a commercial BOTDR (Brillouin optical time-domain reflectometry) to monitor the strain of optical fiber composited in transmission line. The Brillouin spectra of typical optical fiber used in the transmission line are measured by a commercial BOTDR at room temperature, the spectra are fitted and the key parameters are calculated, and then the strain along whole optical fiber is obtained by demodulation. The results show that BOTDR can effectively monitor the optical fiber strain, and the mean standard deviation of strain measured for multiple measurements under the same condition is only about 8 με, which can stastify the requirements of practical cases. The work of this paper lays a foundation for the strain measurement of transmission line.
Research on the Optimal Capacity Configuration Method of Park-type Wind-photovoltaic Storage Complementary Power Generation System
Authors: Yu Changle , Zhang Su , Shen Jianhua , Li Wenwen , Ji Yanchen , Wang Junqi
Published: May 2023

At present, China’s installed renewable energy capacity is growing at a fast rate, and reasonable allocation of the wind turbine, photovoltaic, and energy storage capacity is a prerequisite to ensure the economic and reliable operation of the system. For the park-type grid-connected operation of the wind-photovoltaic storage system, in order to improve the stability of the system and make full use of the distribution grid resources, the operation strategy of the park-type wind-photovoltaic storage system is proposed, and the model of wind-photovoltaic storage is established respectively, and the economy and reliability of the system are considered comprehensively. The objective function of capacity configuration and the constraints of power system operation specification are set up, combined with the time-of-use electricity price, the charging of energy storage battery is preferred at the low valley, and the objective function is solved by a genetic algorithm according to the energy use characteristics of the park, and three configuration schemes are selected from the Pareto front solution. Finally, through the typical day analysis, the results show that the wind-photovoltaic storage capacity allocation method can effectively improve the economy of park operation and the quality of the park power supply.
Cause Analysis and Treatment of Abnormal Vibration of Hydraulic Generator Unit Caused by Coupling Defect
Authors: He Liangchao
Published: May 2023

When a hydropower station 25MW hydropower unit is operated with load after overhaul, the upper bracket vibration will exceed the standard. To find out the cause of the problem and eliminate the fault, the mechanical, electromagnetic, and hydraulic aspects are mainly analyzed and checked. The results show that the excessive vibration of the upper bracket of the unit is caused by the incomplete pre-tightening force between the coupling bolts of the turbine and generator of the unit, as well as the improper location and thickness of the padding. It is characterized by a vibration component whose frequency is between the rotational frequency and twice the rotational frequency. By fully pre-tightening the coupling bolts and restoring the original padding position and thickness, the vibration of the upper bracket, upper guide swing, and other data are significantly improved, and the desired purpose is achieved. The cause analysis and fault treatment of the abnormal vibration of the hydro-generator unit can provide some reference for diagnosing other similar faults.
Application Research of Optical Fiber Sensing Technology in Power Optical Fiber Communication Systems
Authors: Zhang Lujuan , Lei Yu , Luo Yuping , Tan Cuirong , Zhou Wen
Published: May 2023

The distributed optical fiber sensing system uses optical fiber as the sensing element and signal transmission medium at the same time, and adopts advanced Optical Time-domain Reflectometry (OTDR) technology to detect the changes of temperature and strain at different positions along the optical fiber, thus achieving a truly distributed measurement. Using the Micro-structured Optical Time-domain Reflectometry (M-OTDR) optical fiber sensing access network technology, combined with optical link components such as fault locators, can judge the operating status of optical fiber Composite phase cable (IOPPC) lines, and detect faults (such as breakpoints) in optical fiber communication location and diagnosis. The position of the lightning strike is determined by detecting the change of polarization state caused by the transmitted light in the optical fiber inside the IOPPC before and after a lightning strike, and the positioning error is less than 1%. By observing the Brillouin frequency shift chart, the ice state can be accurately identified and the positioning function can be realized. By monitoring the vibration frequency of the IOPPC cable, the line dancing phenomenon can be detected in time to prevent line faults caused by dancing. The online safety and health monitoring of the operating state of transmission lines are realized.
Power Line Data Online Acquisition System of Distribution Network Based on ZigBee
Authors: Zhang Zhanghuang , Tang Yuanchun , Shi Ying
Published: May 2023

Energy Internet promotes the vigorous development of new access network services, which requires access networks to provide support for new services quickly, flexibly, and efficiently. The extension and penetration ability of the access network has been continuously enhanced, and it can adapt to the complex operating environment of the distribution side. Because it is close to the end of the power grid, the network is exposed to the public environment, and it is vulnerable to illegal intrusion, security protection, and other issues. In this paper, based on the ZigBee network, through the study of time series and ARIMA prediction model, first of all, the original data is analyzed in time series, then the data is stabilized. The model is determined and established, and finally, the simulation model is predicted. The test proves that the model studied in this paper has high acquisition accuracy and achieves prediction analysis. Timely warning of meteorological temperature is used as a part of the source data, which can save energy and reduce the acquisition cost while ensuring the amount of data collected.
Analysis of the Influence of Remanence on the Performance of Current Transformer Caused by DC Ice Melting of Transmission Lines
Authors: Zou Chenqiao , Peng Ping , Liu Yonggang , Xu Hao
Published: May 2023

This paper theoretically analyzes the performance changes of the measuring winding and protective winding of the current transformer behind the iron core of the DC ice melting current magnetized transformer. According to the actual ice melting situation, a finite element simulation model is established to calculate the electromagnetic field distribution inside the transformer, quantify the remanence generated by the ice melting, and design a verification test to measure the remanence and transmission characteristics of the current transformer after the ice melting current is magnetized. Based on theory, simulation, and experiment, suggestions for the treatment after ice melting are put forward.
VDCOL Parameter Optimization Method for Improving Voltage Stability of DC Receiving Terminal Power Grid
Authors: Cai Nan , Wang Wenlong , Huo Qidi , Lv Sizhuo , Hu Yuanting , Tang Xiaojun
Published: May 2023

This research based on different startup and operation modes of Heilongjiang receiving power grid, The influence of anti disturbance capability of converter bus on DC recovery characteristics. A VDCOL parameter optimization configuration scheme based on multi feed short circuit ratio (MSCR) is proposed. Through the DC near fault simulation analysis, it is verified that the proposed VDCOL parameter optimization scheme reduces the overall wattless power demand of converter station, and improve Heilongjiang receiving-end grid voltage stability.
Analysis and Optimization of the Impact of Distributed Generation Integration on Distribution Network Loss
Authors: Zhu Xiaofeng , Guo Tiebin , Qi Xuesong , Sun Jia , Guan Xiaozhuo , Li Zhenxin
Published: May 2023

The distribution loss of the distribution network has changed greatly because of the access of distributed generation, which has a certain impact on the power quality of the distribution network. In order to solve the above problems, this paper constructs a 10 kV grid model containing distributed generation, studies the impact of distributed generation on the distribution of network loss, and grasps the characteristics of network loss changes under different scales of distributed generation and different grid-connected conditions. Finally, this paper constructs a mathematical model containing distributed generation and proposes control measures to ensure the safe and stable operation of the grid.
Sliding Mode Control of PMSM Control Based on Novel Exponential Reaching Law
Authors: Zheng Chenyang , Qin Xin , Chen Guochu
Published: May 2023

To overcome the issue that the commonly used linear PI controller is not strong in the nonlinear system and cannot be satisfied with the performance requirements of fast and stable speed modulation of PMSM, a new type of exponential convergence law is devised on the basis of the exponential approximation law of conventional sliding mode controller to accelerate the convergence of the Speed control system and improve the jitter problem of the system. Three models of rotational speed controllers built in Simulink are compared in cases of no-load start-up and sudden load addition, and the new exponential reaching law presented in this article can be effective in improving the control performance of the system, strengthening the anti-disturbance capability and robustness of the Speed control system.
Application of direct energy balance control in Supercritical Unit Coordinated Control System
Authors: Si Ruicai , Wang Songhan , Dou Zhongzhou , Wang Zhongyan , Li Xiucheng , Sun Bo , Liu Xiwen , Li Jia , Zhou Chi , Liu Chao
Published: May 2023

The direct energy balance control strategy is analyzed and combined with the characteristics of supercritical units. The direct energy balance strategy is reconstructed. The reconstructed direct energy balance signal is applied to the boiler master control feedforward in the coordinated control, taking a power plant’s coordinated control system as an example, t. Thus, it is applied to the control of supercritical units, which improves the regulation quality of the control system in a steady and dynamic state, and effectively solves the problems of large fluctuation of mainstream pressure, locked increase, and decrease of load command, frequent withdrawal of coordinated control and unqualified AGC index.
Smart Substation Construction Scheme Based on Micropower Communication and Edge Internet of Things Agent
Authors: Kou Zheng , He WenHao , Na Qin , Yang Yue
Published: May 2023

In recent years, the digital transformation of power grids has become a new trend in the development of power grid enterprises. As a key link, the digitalization and intellectualization of substations have been included in the development plans of major power grid companies. This paper introduces a construction scheme for smart substations. By deploying edge Internet of Things agents, the construction scheme from online monitoring of electrical quantities of electric power equipment to data edge aggregation and data application is realized, which provides an effective solution for the construction of smart substations.
Integral Sliding Mode Variable Structure Control of Synchronous Reluctance Motors
Authors: Chu ChunLin , You XiaoXiao , Sun BaoJiang , Zhang TianYuan
Published: May 2023

Aiming at the problem of jitter in the speed when the load changes abruptly during the operation of a synchronous reluctance motor and the poor resistance to load disturbance, an integral type sliding film variable structure control algorithm is proposed. The speed regulation is controlled by sliding mode, PI controls the current regulation, the Simulink simulation model of the system is built, and simulation experiments are conducted. The results show that, compared with the traditional PI control, the system’s dynamic response is faster, the resistance to load disturbance is stronger, and the robustness is high.
A Method to Optimize the Inverse Operation of Electric Field Based on A Smart Algorithm
Authors: Zhao Qiang , Yang Shenglan , Lu li , Liu Wei , Jiang Zefeng , Yang Wei
Published: May 2023

Along with the progress of electric network scale, power load and transmission lines are also growing rapidly in China. In addition, the transmission state detection is getting more and more attention. The paper explored the electric field under the HV (high voltage) line of transmission and researched the inverse operation principle of electric field. To solve the multiple parameter solutions in electric field inversion, the paper proposed two smart algorithms. Firstly, the fitness function of voltage value is extracted, therefore inversion algorithm global optimization function of the electric field is proposed. Secondly, an example of HV transmission line verified the effectiveness of the inverse optimization algorithm. Last, the case results indicate that the optimization methods are effective and accurate.
What climate and environmental benefits of regenerative agriculture practices? an evidence review
Authors: Rehberger Emily , West Paul C , Spillane Charles , McKeown Peter C
Published: May 2023

Regenerative agriculture aims to increase soil organic carbon (SOC) levels, soil health and biodiversity. Regenerative agriculture is often juxtaposed against ‘conventional’ agriculture which contributes to land degradation, biodiversity loss, and greenhouse gas emissions. Although definitions of regenerative agriculture may vary, common practices include no or reduced till, cover cropping, crop rotation, reduced use or disuse of external inputs such as agrichemicals, use of farm-derived organic inputs, increased use of perennials and agroforestry, integrated crop-livestock systems, and managed grazing. While the claims associated with some of these practices are supported by more evidence than others, some studies suggest that these practices can be effective in increasing soil organic carbon levels, which can have positive effects both agriculturally and environmentally. Studies across these different regenerative agriculture practices indicate that the increase in soil organic carbon, in comparison with conventional practices, varies widely (ranging from a nonsignificant difference to as high as 3 Mg C/ha/y). Case studies from a range of regenerative agriculture systems suggest that these practices can work effectively in unison to increase SOC, but regenerative agriculture studies must also consider the importance of maintaining yield, or risk the potential of offsetting mitigation through the conversion of more land for agriculture. The carbon sequestration benefit of regenerative practices could be maximized by targeting soils that have been intensively managed and have a high carbon storage potential. The anticipated benefits of regenerative agriculture could be tested by furthering research on increasing the storage of stable carbon, rather than labile carbon, in soils to ensure its permanence.
Laplacian dynamics of convergent and divergent collective behaviors
Authors: Tian Yang , Xu Yunhui , Sun Pei
Published: May 2023

Collective dynamics is ubiquitous in various physical, biological, and social systems, where simple local interactions between individual units lead to complex global patterns. A common feature of diverse collective behaviors is that the units exhibit either convergent or divergent evolution in their behaviors, i.e. becoming increasingly similar or distinct, respectively. The associated dynamics changes across time, leading to complex consequences on a global scale. In this study, we propose a generalized Laplacian dynamics model to describe both convergent and divergent collective behaviors, where the trends of convergence and divergence compete with each other and jointly determine the evolution of global patterns. We empirically observe non-trivial phase-transition-like phenomena between the convergent and divergent evolution phases, which are controlled by local interaction properties. We also propose a conjecture regarding the underlying phase transition mechanisms and outline the main theoretical difficulties for testing this conjecture. Overall, our framework may serve as a minimal model of collective behaviors and their intricate dynamics.
Syndication network associates with specialisation and performance of venture capital firms
Authors: Yao Qing , Ma Shaodong , Liang Jing , Christensen Kim , Jing Wanru , Li Ruiqi
Published: May 2023

The Chinese venture capital (VC) market is a young and rapidly expanding financial subsector. Gaining a deeper understanding of the investment behaviours of VC firms is crucial for the development of a more sustainable and healthier market and economy. Contrasting evidence supports that either specialisation or diversification helps to achieve a better investment performance. However, the impact of the syndication network is overlooked. Syndication network has a great influence on the propagation of information and trust. By exploiting an authoritative VC dataset of thirty-five-year investment information in China, we construct a joint-investment network of VC firms and analyse the impacts of syndication and diversification on specialisation and investment performance. There is a clear correlation between the syndication network degree and specialisation level of VC firms, which implies that the well-connected VC firms are diversified. More connections generally bring about more information or other resources, and VC firms are more likely to enter a new stage or industry with some new co-investing VC firms when compared to a randomised null model. Moreover, autocorrelation analysis of both specialisation and success rate on the syndication network indicates that feature clustering of similar VC firms is roughly limited to the secondary neighbourhood. When analysing local feature clustering patterns, we discover that, contrary to popular beliefs, there is no apparent successful club of investors. In contrast, investors with low success rates are more likely to cluster. Our discoveries enrich the understanding of VC investment behaviours and can assist policymakers in designing better strategies to promote the development of the VC industry.
Path to the fabrication of efficient, stable and commercially viable large-area organic solar cells
Authors: Rasool Shafket , Yeop Jiwoo , Cho Hye Won , Lee Woojin , Kim Jae Won , Yuk Dohun , Kim Jin Young
Published: May 2023

Organic solar cells (OSCs) have reached an outstanding certified power conversion efficiency (PCE) of over 19% in single junction and 20% in tandem architecture design. Such high PCEs have emerged with outstanding Y-shaped Y6 non-fullerene acceptors (NFAs), together with PM6 electron donor polymers. PCEs are on the rise for small-area OSCs. However, large-area OSC sub-modules are still unable to achieve such high PCEs, and the highest certified PCE reported so far is ∼12% having an area of 58 cm2. To fabricate efficient large-area OSCs, new custom-designed NFAs for large-area systems are imminent along with improvements in the sub-module fabrication platforms. Moreover, the search for stable yet efficient OSCs is still in progress. In this review, progress in small-area OSCs is presented with reference to the advancement in the chemical structure of NFAs and donor polymers. Finally, the life-cycle assessment of OSCs is presented and the energy payback time of the efficient and stable OSCs is discussed and lastly, an outlook for the OSCs is given.
Chow dilogarithm and strong Suslin reciprocity law
Authors: Bolbachan Vasily
Published: May 2023

We prove a conjecture of A. Goncharov concerning strong Suslin reciprocity law. The main idea of the proof is the construction of the norm map on so-called lifted reciprocity maps. This construction is similar to the construction of the norm map on Milnor

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-theory. As an application, we express Chow dilogarithm in terms of Bloch-Wigner dilogarithm. Also, we obtain a new reciprocity law for four rational functions on an arbitrary algebraic surface with values in the pre-Bloch group.
A-287 UTILITY OF CORRELATION BETWEEN TI-RADS AND BETHESDA CLASSIFICATION TO ESTIMATE RISK OF MALIGNANCY FOR CYTOLOGICALLY INDETERMINATE THYROID NODULES
Authors: Chereau N , Menegaux F , Bertin J-B
Published: May 2023

Background

Currently, we are directing therapeutic strategy based on the results of fine-needle aspiration biopsy defined by the Bethesda classification. The TI-RADS classification of ultrasound features can help surgeons to estimate the risk of malignancy (ROM). The aim of this study was to explore the correlation between the two classifications.

Methods

All patients who underwent a total or hemithyroidectomy from January 2021 to June 2022 in a high-volume endocrine surgery center were included in this study. The results of TI-RADS classification and Bethesda classification were collected, as well as the pathologic results. Multivariable logistic regression analysis was performed to determine whether malignancy correlated with the Bethesda diagnosis and TI-RADS score.

Results

During the study period, 1903 patients had thyroid surgery including 848 (44.6%) who had a final pathologically verified thyroid cancer. Bethesda group III was associated with a ROM of 25.4%; in association with a TI-RADS 5 the ROM increased to 48.6%. Bethesda IV was associated with a ROM of 33.5% but, when combined with TI-RADS 3 or 5, the ROM ranged between 33.3 and 44.8% respectively. Bethesda 5 group was associated with a ROM of 81.8% and in combination with TI-RADS 5 score the ROM increased to 90.2%. Our model used the TI-RADS score to stratify the ROM for each Bethesda diagnostic group. We found that the model was more accurate than using the Bethesda diagnosis alone especially for estimation of ROM for Bethesda III thyroid nodules classified as Bethesda III.

Conclusion

Use of TI-RADS scores for each Bethesda diagnostic group allow a more accurate assessment of ROM for indeterminate thyroid nodules.
A-257 OMISSION OF LYMPH NODE DISSECTION IN MEDULLARY THYROID CANCER WITHOUT A DESMOPLASTIC STROMAL REACTION, COULD BE AN OPTION?
Authors: Gómez-Ramírez J , Luengo P , Muñoz de Nova J L , Ruz Caracuel I , Rosell A
Published: May 2023

Background

Predictive criteria to determine the absence of node metastases from thyroid specimens are scarce for sporadic medullary thyroid cancer (MTC). It has been suggested that lymph node dissection could be avoided in patients with MTC without a desmoplastic stromal reaction (DSR-negative). The aim of our study was to perform analyse the correlation between DSR status and lymph node involvement in order to establish a criterion on which to base prophylactic surgery in these patients.

Methods

This was a multicentric retrospective cohort study of a prospectively maintained database of patients with medullary thyroid cancer treated in two tertiary hospitals using a standardised protocol and subdivided into DSR-negative and -positive groups. Intraoperative, long-term clinical and biochemical follow-up data were collected, and baseline parameters and histopathological characteristics were compared between groups.

Results

The study included 29 patients. In the DSR-negative group (24.1% of all tumours) no patient had central or lateral lymph node or distant metastases at diagnosis or during follow-up, and all patients were biochemically cured. In the DSR-positive group (75.9% all tumours), lymph nodes were present in 66% of patients. DSR-negative tumours were more often stage pT1a and levels of basal calcitonin were significantly lower.

Conclusion

Lymph node surgery may be individualised in medullary thyroid cancer based on intraoperative analysis of the DSR. Patients with DSR-negative tumours may not require lymph node dissection.
A-247 IMPACT OF ADRENAL SURGEON VOLUME ON OUTCOME: ANALYSIS OF THE UNITED KINGDOM REGISTRY OF ENDOCRINE AND THYROID SURGERY (UKRETS)
Authors: Rajan S , Abdelhamid A , Patel N , Stechman M , Balasubramanian S , Aspinall S
Published: May 2023

Background

Although there is surgeon volume-outcome effect in adrenal surgery the threshold for ‘high volume’ surgeon remains controversial. This retrospective cohort study of the UKRETS database explores this issue further.

Methods

Adrenal data on adults aged 18–90 years from 2004 to 2021 was analysed. Outcomes included postoperative complications, post-operative, length of stay (LOS) and mortality. Factors included in multivariable analysis were patient age, gender, diagnosis, surgical approach, anatomy, and surgeon volume. Cases with missing data on any variable and LOS > 60 days were excluded.

Results

Of 6174 operations, 4464 (72.3%) cases were analysed. Postoperative complications occurred in 418/4064 (9.4%) and mortality in 14/4064 (0.3%). Median LOS was 3 (IQR 2-5) days. Co-variables significantly (p<0.05) associated with adverse outcomes were: postoperative complications - age [OR 1.02 (95% CI 1.01-1.03)], adrenal cancer [OR 1.64 (95% CI 1.14-2.36)], bilateral surgery [OR 1.66 (95% CI 1.03-2.69)] and surgeon volume [OR 0.98 (95% CI 0.96-0.99)]; mortality - age [OR 1.08 (95% CI 1.03-1.13)], laparoscopic approach [OR 0.08 (95% CI 0.02-0.27)] and bilateral surgery [OR 6.93 (95% CI 1.40-34.34)] and LOS (standardised beta co-efficient) - male sex (-0.03), age (0.09), phaeochromocytoma (0.07), adrenal cancer (0.08), bilateral surgery (0.11), laparoscopic approach (-0.40) and surgeon volume (-0.06).

Conclusion

Surgery for adrenal cancer and bilateral tumours could be restricted to high volume surgeons, but the threshold still needs to be defined.