To solve the problem of soil loosening caused by whole plant vibration during the operation of a vibrating blueberry harvester,the force model of the blueberry tree containing root soil was established and *** main fa...
详细信息
To solve the problem of soil loosening caused by whole plant vibration during the operation of a vibrating blueberry harvester,the force model of the blueberry tree containing root soil was established and *** main factors affecting the impact force of the shaker were the curvature of the shaker,the branch curvature,and the equivalent elastic modulus at the impact *** the analysis of the transfer law of vibration between the exciting force and the root-soil complex,it is concluded that the shear strength decreases with the decrease of the internal friction angle,resulting in loose soil and easy toppling of the fruit *** element simulation was used to analyze the force of the blueberry *** results showed that the lower the excitation height,the more drastic the fluctuation of the root-soil *** the range of excitation height from 200 mm to 500 mm,soil acceleration increased by 45.5%on average for every 150 mm *** 200 mm to 50 mm,the average soil acceleration increased by 69.1%.Finally,through the field excitation sensor test,the sensor was buried in 200 mm,100 mm,and 0 mm(that is,placed on the surface)of soil,and the exciting force was applied to blueberry branches at heights of 50 mm,200 mm,350 mm,and 500 mm,respectively,for four times,and then the soil acceleration was output.A total of 48 sets of experimental data were *** combining the scattering data obtained from the experiment with the simulated curve,it can be analyzed that when the excitation heights were 50 mm and 500 mm,the soil fluctuation at the depth of 100 mm was close to the simulated average *** the excitation heights were 200 mm and 350 mm,the fluctuation of surface soil with a depth of 0 mm was close to the simulated average *** the excitation height was 500 mm,the root-soil complex fluctuated twice due to the obvious reciprocating swing of the fruit *** very little vibration energy was consumed during transmission,the
Titanium alloy has been applied in the field of aerospace manufacturing for its high specific strength and ***,these properties also cause general problems in the machining,such as processing inefficiency,serious wear...
详细信息
Titanium alloy has been applied in the field of aerospace manufacturing for its high specific strength and ***,these properties also cause general problems in the machining,such as processing inefficiency,serious wear,poor workpiece face quality,*** at the above problems,this paper carried out a comparative experimental study on titanium alloy milling based on the CAMCand *** variation law of cutting force and wear morphology of the two tools were obtained,and the wear mechanism and the effect of wear on machining quality were *** conclusion is that in contrast with BEMC,under the action of cutting thickness thinning mechanism,the force of CAMC was less,and its fluctuation was more *** flank wear was uniform and near the cutting edge,and the wear rate was *** the early period,the wear mechanism of CAMC was mainly ***,oxidative wear also occurred with ***,the surface residual height of CAMC was *** is no obvious peak and trough accompanied by fewer surface defects.
With the development of machine tools to high precision and high automation, thermal error has become the key reason to hinder the improvement of thermal stability of machine tools. The spindle electro thermal error i...
详细信息
Federated learning (FL) is a promising decentralized machine learning approach that enables multiple distributed clients to train a model jointly while keeping their data private. However, in real-world scenarios, the...
详细信息
Federated learning (FL) is a promising decentralized machine learning approach that enables multiple distributed clients to train a model jointly while keeping their data private. However, in real-world scenarios, the supervised training data stored in local clients inevitably suffer from imperfect annotations, resulting in subjective, inconsistent and biased labels. These noisy labels can harm the collaborative aggregation process of FL by inducing inconsistent decision boundaries. Unfortunately, few attempts have been made towards noise-tolerant federated learning, with most of them relying on the strategy of transmitting overhead messages to assist noisy labels detection and correction, which increases the communication burden as well as privacy risks. In this paper, we propose a simple yet effective method for noise-tolerant FL based on the well-established co-training framework. Our method leverages the inherent discrepancy in the learning ability of the local and global models in FL, which can be regarded as two complementary views. By iteratively exchanging samples with their high confident predictions, the two models “teach each other” to suppress the influence of noisy labels. The proposed scheme enjoys the benefit of overhead cost-free and can serve as a robust and efficient baseline for noise-tolerant federated learning. Experimental results demonstrate that our method outperforms existing approaches, highlighting the superiority of our method.
Due to the complex structure and large size of large-capacity oil-immersed power transformers,it is difficult to predict the winding temperature distribution directly by numerical analysis.A 180 MVA,220 kV oil-immerse...
详细信息
Due to the complex structure and large size of large-capacity oil-immersed power transformers,it is difficult to predict the winding temperature distribution directly by numerical analysis.A 180 MVA,220 kV oil-immersed self-cooling power transformer is used as the research *** authors decouple the internal fluid domain of the power transformer into four regions:high voltage windings,medium voltage windings,low voltage windings,and radiators through fluid networks and establish the 3D fluidtemperature field numerical analysis model of the four regions,*** results of the fluid network model are used as the inlet boundary conditions for the 3D fluidtemperature numerical analysis *** turn,the fluid resistance of the fluid network model is corrected according to the results of the 3D fluid-temperature field numerical analysis *** prediction of the temperature distribution of windings is realised by the coupling calculation between the fluid network model and the 3D fluid-temperature field numerical analysis *** on this,the effect of the loading method of the heat source is also investigated using the proposed *** hotspot temperatures of the high-voltage,medium-voltage,and low-voltage windings are 89.43,86.33,and 80.96°C,***,an experimental platform is built to verify the *** maximum relative error between calculated and measured values is 4.42%,which meets the engineering accuracy requirement.
The multitude of airborne point clouds limits the point cloud processing *** are grouped based on similar points,which can effectively alleviate the demand for computing resources and improve processing ***,existing s...
详细信息
The multitude of airborne point clouds limits the point cloud processing *** are grouped based on similar points,which can effectively alleviate the demand for computing resources and improve processing ***,existing superpoint segmentation methods focus only on local geometric structures,resulting in inconsistent spectral features of points within a *** feature inconsistencies degrade the performance of subsequent ***,this study proposes a novel Superpoint Segmentation method that jointly utilizes spatial Geometric and Spectral Information for multispectral point cloud superpoint segmentation(GSI-SS).Specifically,a similarity metric that combines spatial geometry and spectral information is proposed to facilitate the consistency of geometric structures and object attributes within segmented *** the formation of the primary superpoints,an intersuperpoint pointexchange mechanism that maximizes feature consistency within the final superpoints is *** are conducted on two real multispectral point cloud datasets,and the proposed method achieved higher recall,precision,F score,and lower global consistency and feature classification *** experimental results demonstrate the superiority of the proposed GSI-SS over several state-of-the-art methods.
The use of generative adversarial network(GAN)-based models for the conditional generation of image semantic segmentation has shown promising results in recent ***,there are still some limitations,including limited di...
详细信息
The use of generative adversarial network(GAN)-based models for the conditional generation of image semantic segmentation has shown promising results in recent ***,there are still some limitations,including limited diversity of image style,distortion of detailed texture,unbalanced color tone,and lengthy training *** address these issues,we propose an asymmetric pre-training and fine-tuning(APF)-GAN model.
Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological *** generators,designed with specific s...
详细信息
Hydrodynamic cavitation,as an efficient technique applied in many physical and chemical treatment methods,has been widely used by various industries and in several technological *** generators,designed with specific structures and parameters,can produce cavitation effects,thereby enabling effective treatment and reasonable transformation of *** paper reviews the design principles,performance,and practical applications associated with different types of cavitation generators,aiming to provide theoretical support for the optimization of these *** systematically analyzes the underpinning mechanisms and the various factors influencing the cavitation phenomena,also conducting a comparative analysis of the performance of different types of *** applications dealing with wastewater treatment,chemical reaction acceleration,and other fields are discussed together with the advantages,disadvantages,and applicability of each type of cavitation *** also explore research progress in areas such as cavitation stability,energy efficiency,and equipment design *** study concludes by forecasting the application prospects of intelligent design and computational fluid dynamics(CFD)in optimizing and advancing cavitation *** proposes new ideas for the further development of cavitation technology and highlights directions for its widespread future application.
Accumulative alternating back extrusion was a potential fine-grain modification *** this paper,it was an innovative attempt to develop high-performance magnesium alloy sheet by this *** the condition of 350 K,commerci...
详细信息
Accumulative alternating back extrusion was a potential fine-grain modification *** this paper,it was an innovative attempt to develop high-performance magnesium alloy sheet by this *** the condition of 350 K,commercial AZ31 magnesium alloy was made into billet by accumulative alternating back extrusion,and then extruded into fine-grain magnesium alloy *** a systematic study of its microstructure and mechanical properties,the results showed that the initial state had an important influence on the evolution of the structure during *** accumulative alternating back extrusion to produce the billet,the grain size of the sheet obtained by extrusion was significantly refined,which was related to the accumulation of deformation and grain refinement during the alternating loading *** refinement caused the proportion of dynamic recrystallization inside the sheet with 2 cycles of accumulative alternating back extrusion to drop to 27%.With the increase of extrusion cycles from 2 to 4,the high density of dislocations led to an increase in the proportion of dynamic recrystallization and finer *** texture changed from strong basal texture to weak bimodal *** results of uniaxial tensile test show that due to grain refinement and texture change,the yield strength was significantly reduced,and the plasticity was significantly *** was verified that accumulative alternating back extrusion was meaningful for subsequent processing,and it also provided scientific guidance for the development of fine-grained magnesium alloy sheet.
Video deblurring is a fundamental problem in low-level vision, and many methods have employed designs based on CNNs and transformers. Traditional CNNs often require deeper architectures to achieve a larger receptive f...
详细信息
暂无评论