Explore the vast range of titles available.

Modern power systems are evolving toward hybrid AC/DC distribution networks to enhance efficiency, improve renewable energy integration, and support bidirectional power flow. However, these systems present complex challenges for fault detection and localization due to the diversity of AC and DC fault characteristics and their intricate operational behavior. This paper proposes a novel federated learning (FL)-based fault analysis framework that enables privacy-preserving, decentralized training while handling bidirectional energy flow and inverter-based RES integration. The approach introduces a complete solution encompassing fault detection, classification and localization using feature-extracted voltage and current signals. Simulation results under various fault types, network topologies, and operational modes confirm the method’s robustness and real-time accuracy. The proposed framework contributes to intelligent, scalable, and secure fault management in hybrid AC/DC networks.

In view of the differences between Chinese and German regulations of bolt end distance, experiments for connection specimens with different bolt end distances were designed and conducted. The finite element models took into account the material nonlinearities, geometry nonlinearities and contact nonlinearities. The major factors were selected, and parametric studies were performed. It is found that FEA (finite element analysis) were in good agreement with the experimental results. The ultimate carrying capacity increases with the increase of bolt end distance. It is recommended to extend the minimum allowable bolt end distance to within 1.2d0, but it’s carrying capacity should be appropriately decreased. When the bolt end distance e1 is less than 1.2d0, the bolts were torn off at the end. When the bolt end distance e1 is greater than or equal to 1.2d0, the specimens damaged of their ultimate carrying capacities. The increase of bolt diameter and number has little influence on the ultimate carrying capacities of specimens, but all of them indicate good ductility. Finally, using the analysis data and combining with the calculation method of the ultimate bearing capacity of the bolt connection in Chinese codes, the proposed formula when the bolt end distance e1 is in the range of 1.2d0 to 4d0 were proposed, and the finite element calculation verification is carried out.

This paper aims to study the weldability of butt weld of double-layer steel plates. Experiments for three groups of specimens subjected to various parameters are first conducted to obtain angular deformation, residual stress and temperature data. Then, 3-D finite element (FE) thermal simulation of butt welding is carried out to obtain the load-displacement curves under different included angles and weld length. Moreover, the butt welded steel plate welds were parametric analyzed for the stress concentration factor and the formula for the stress concentration factor was fitted according to the data. The analytical results have shown that double-layer butt welded steel plates with better performance compared to single-layer butt welded steel plates, and the proposed stress concentration factor formula predicts well and thus has certain reference value.

For a long time, spatial structures have been widely used. However, compared with the high strength of their material, their stability is weak, and especially sensitive to damage and defects. This feature has increased the engineering industry’s high requirements for their stability analysis. As we all know, this problem is more prominent for the reticulated shell structure, which is a classic representative of the spatial structure. However, in the current analysis methods for the stability of reticulated shells, the deterministic analysis method cannot consider the random characteristics of defects. Other random methods, such as the random defect modal method, and many improved methods, require more samples and calculation time. This unfavorable situation makes its engineering application greatly restricted. In addition, the random modal superposition method and derivation method based on Monte Carlo has not fundamentally changed this limitation. In order to fundamentally overcome this traditional shortcoming, this paper comprehensively studies the advantages of the high accuracy of the random defect modal method and the improved method, and at the same time, investigates the speed advantage of the response surface method, and then creates a new stochastic analysis method based on the response surface method. Finally, the analysis results of the calculation examples in this paper prove that it successfully balances and satisfies the dual requirements of accuracy and speed required for calculating the stability of the reticulated shell structure. Moreover, it has universal applicability to different forms of reticulated shells, such as classic 6-point flat domes, traditional reticulated shell structures, and bionic reticulated shell structures, and even other types of spatial structures.

Actual evapotranspiration is a key process of hydrological cycle and a sole term that links land surface water balance and land surface energy balance. Evapotranspiration plays a key role in simulating hydrological effect of climate change, and a review of evapotranspiration estimation methods in hydrological models is of vital importance. This paper firstly summarizes the evapotranspiration estimation methods applied in hydrological models and then classifies them into the integrated converting methods and the classification gathering methods by their mechanism. Integrated converting methods are usually used in hydrological models and two differences exist among them： one is in the potential evaporation estimation methods, while the other in the function for defining relationship between potential evapora tion and actual evapotranspiration. Due to the higher information requirements of the Pen- man-Monteith method and the existing data uncertainty, simplified empirical methods for calculating potential and actual evapotranspiration are widely used in hydrological models. Different evapotranspiration calculation methods are used depending on the complexity of the hydrological model, and importance and difficulty in the selection of the most suitable evapotranspiration methods is discussed. Finally, this paper points out the prospective de velopment trends of the evapotranspiration estimating methods in hydrological modeling.

This research explores machine learning (ML) techniques, with an emphasis on neural networks (NNs), to predict household energy consumption in the context of smart grids. The study evaluates algorithms such as CNN, LSTM, RF, AdaBoost, and CatBoost with a primary focus on hybrid models to enhance forecast precision. The research adopts a comprehensive data collection strategy while dividing the time series data into training (80%) and testing (20%) segments for rigorous model evaluation. Hybrid approaches that combine several algorithms significantly outperform single models, and LSTM-CatBoost is at the forefront by exhibiting lower error rates and higher R2 values. To avoid overfitting, the research employs cross-validation in conjunction with early stopping, thus, producing robust and trustworthy models. The paper provides a wealth of information on energy forecasting that paves the way for the energy efficiency and sustainability of smart grids, which are essentially energy management systems based on the latest technology and consumer feedback mechanisms.

By inputting two groups of seismic waves with phase differences of 0.16s, 0.34s, 0.5 and 0.34s, 0.66s, 1.0s to column elements divided into four parts of lower story of finite element model with insertion method, this paper analyzed the influence of wave passage effect on seismic responses of truss string structure of Guangzhou Convention and Exhibition Centre co-working with its base frame by time history analysis method. The results show that: because of natural vibration characteristics of structure, wave traveling has some effect on seismic responses of truss string structure of Guangzhou Convention and Exhibition Centre.

The process and thought for the approach bridge of Suiwei bridge design using the method of isolation and energy dissipation were proposed in this paper. The concept of protecting a bridge from the damaging effects of an earthquake by introducing isolating bearings to isolate it from the moving ground is an attractive one. Firstly, the sizes of the laminated rubber bearings and the dia- meters of lead plugs are calculated with static analysis. Then the internal forces of the piers and the damping ratio of the isolated bridge needed to restrict the seismic deformation to 8cm during earth- quakes with seldom intensity were calculated using the Response Spectrum Method, and the result verified with dynamic time history method demonstrates that the Response Spectrum Design Method can restrict the girder displacement to 8cm during large earthquake and reach the goal of 25 percent shock reduction. The design process can be of reference to the bridge design with isolation and energy dissipation.

The seasonal variability and spatial distribution of precipitation are the main cause of flood and drought events. The study of spatial distribution and temporal trend of precipitation in river basins has been paid more and more attention. However, in China, the precipitation data are measured by weather stations （WS） of China Meteorological Administration and hydrological rain gauges （RG） of national and local hydrology bureau. The WS data usually have long record with fewer stations, while the RG data usually have short record with more stations. The consistency and correlation of these two data sets have not been well understood. In this paper, the precipitation data from 30 weather stations for 1958-2007 and 248 rain gauges for 1995-2004 in the Haihe River basin are examined and compared using linear regression, 5-year moving average, Mann-Kendall trend analysis, Kolmogorov-Smirnov test, Z test and F test methods. The results show that the annual precipitation from both WS and RG records are normally distributed with minor difference in the mean value and variance. It is statistically feasible to extend the precipitation of RG by WS data sets. Using the extended precipitation data, the detailed spatial distribution of the annual and seasonal precipitation amounts as well as their temporal trends are calculated and mapped. The various distribution maps produced in the study show that for the whole basin the precipitation of 1958-2007 has been decreasing except for spring season. The decline trend is significant in summer, and this trend is stronger after the 1980s. The annual and seasonal precipitation amounts and changing trends are different in different regions and seasons. The precipitation is decreasing from south to north, from coastal zone to inland area.

As an essential dimension of economic inequality, consumption inequality is tightly associated with public welfare. This study investigates the effect of consumption inequality on individuals’ subjective well-being (SWB) in China using data from the 2014, 2018, and 2020 China Family Panel Studies. The findings indicate that consumption inequality has a significant negative impact on SWB. Specifically, for every unit increase in consumption inequality, the probability of individuals rating their SWB as “Happy” and “Very happy” decreases by 0.37% and 5.45% respectively. In addition, individuals’ confidence about their future serves as an intermediary in the connection between consumption inequality and SWB. The investigation of heterogeneity evidences that the adverse impact of consumption inequality on SWB is more pronounced in terms of subsistence and development expenditures. Consumption inequality affects SWB more seriously among lower-income and urban residents. Overall, this study holds important implications for addressing economic inequality to bolster individuals’ welfare.