The manual picking of strawberries is inefficient and costly,limiting scalability and economic benefits.Mechanizing this process reduces labor demands,improves working conditions,and modernizes the strawberry industry...The manual picking of strawberries is inefficient and costly,limiting scalability and economic benefits.Mechanizing this process reduces labor demands,improves working conditions,and modernizes the strawberry industry.Target detection technology,crucial for mechanized picking,must accurately determine strawberry maturity.This study presents an enhanced YOLOv8s model addressing current machine learning issues like accuracy,parameters,and complexity.The improved model replaces the Bottleneck structure in C2f with the FasterNet network,integrates an efficient multi-scale attention mechanism,and uses the Ghost module in the backbone to reduce computational load while maintaining performance.It also introduces Wise-IoU for bounding box regression loss,improving recognition accuracy.The YOLOv8s-FEGW model achieves a 93.8%mAP in detecting strawberry ripeness,with significant reductions in parameters(36.8%),complexity(34.6%),and model size(37.7%),alongside a 12.7% Frames Per Second(FPS)boost.These enhancements result in excellent detection capabilities,supporting agricultural automation and intelligence.展开更多
When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on ...When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on optimizing the furnace temperature curve under varying settings of reflow oven zone temperatures and conveyor belt speeds.To address this,the research sequentially develops a heat transfer model for reflow soldering,an optimization model for reflow furnace conditions using the differential evolution algorithm,and an evaluation and decision model combining the differential evolution algorithm with the Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)method.This approach aims to determine the optimal furnace temperature curve,zone temperatures of the reflow oven,and the conveyor belt speed.展开更多
This paper is concerned with the problem of finitetime control for a class of discrete-time networked systems.The measurement output and control input signals are quantized before being transmitted in communication ne...This paper is concerned with the problem of finitetime control for a class of discrete-time networked systems.The measurement output and control input signals are quantized before being transmitted in communication network.The quantization density of the network is assumed to be variable depending on the throughputs of network for the sake of congestion avoidance.The variation of the quantization density modes satisfies persistent dwell-time(PDT)switching which is more general than dwell-time switching in networked channels.By using a quantization-error-dependent Lyapunov function approach,sufficient conditions are given to ensure that the quantized systems are finite-time stable and finite-time bounded with a prescribed H∞performance,upon which a set of controllers depending on the mode of quantization density are designed.In order to show the effectiveness of the designed H_∞controller,we apply the developed theoretical results to a numerical example.展开更多
Epigenetics refers to how chromatin-associated factors and reversible chromatin modifications maintain DNA-based programs by regulating the chromatin structure(Strahl and Allis,2000).In recent years,genome sequencing ...Epigenetics refers to how chromatin-associated factors and reversible chromatin modifications maintain DNA-based programs by regulating the chromatin structure(Strahl and Allis,2000).In recent years,genome sequencing studies of cancer have shown that genes encoding epigenetic factors are commonly mutated in cancer(Garraway and Lander,2013).Dys regulated,or mutant.展开更多
By imitating the body structure and movement mode of the crab in nature,a novel stick–slip piezo-driven positioning platform was proposed by employing the bionic flexible hinge mechanism with a symmetrical structure ...By imitating the body structure and movement mode of the crab in nature,a novel stick–slip piezo-driven positioning platform was proposed by employing the bionic flexible hinge mechanism with a symmetrical structure and two piezoelectric stacks.The structural design and bionic motion principle were discussed,followed by analyzing the feasibility,safety,and output magnification ratio of the bionic flexible hinge mechanism via the stiffness matrix method and finite element simulation.To investigate the output performances of the positioning platform,a prototype was fabricated and an experiment system was established.Stepping characteristics of the positioning platform under various driving voltages were characterized,and the results indicated that the positioning platform could move steadily under various driving voltages.Within 1 s,the differences between the forward and reverse output displacement were less than 3%under different driving frequencies,proving the high bidirectional motion symmetry.The maximum driving speed of 5.44 mm/s was obtained under the driving voltage of 120 V and driving frequency of 5 Hz.In addition,the carrying load capacity of the positioning platform was tested by standard weights,and the results showed that when the carrying load reached 10 N,the driving speed could still reach 60μm/s.展开更多
基金funded by the National Engineering Research Center of Special Equipment and Power System for Ship and Marine Engineering and the Shanghai Engineering Research Center of Ship Intelligent Maintenance and Energy Efficiency Control(20DZ2252300).
文摘The manual picking of strawberries is inefficient and costly,limiting scalability and economic benefits.Mechanizing this process reduces labor demands,improves working conditions,and modernizes the strawberry industry.Target detection technology,crucial for mechanized picking,must accurately determine strawberry maturity.This study presents an enhanced YOLOv8s model addressing current machine learning issues like accuracy,parameters,and complexity.The improved model replaces the Bottleneck structure in C2f with the FasterNet network,integrates an efficient multi-scale attention mechanism,and uses the Ghost module in the backbone to reduce computational load while maintaining performance.It also introduces Wise-IoU for bounding box regression loss,improving recognition accuracy.The YOLOv8s-FEGW model achieves a 93.8%mAP in detecting strawberry ripeness,with significant reductions in parameters(36.8%),complexity(34.6%),and model size(37.7%),alongside a 12.7% Frames Per Second(FPS)boost.These enhancements result in excellent detection capabilities,supporting agricultural automation and intelligence.
文摘When soldering electronic components onto circuit boards,the temperature curves of the reflow ovens across different zones and the conveyor belt speed significantly influence the product quality.This study focuses on optimizing the furnace temperature curve under varying settings of reflow oven zone temperatures and conveyor belt speeds.To address this,the research sequentially develops a heat transfer model for reflow soldering,an optimization model for reflow furnace conditions using the differential evolution algorithm,and an evaluation and decision model combining the differential evolution algorithm with the Technique for Order Preference by Similarity to Ideal Solution(TOPSIS)method.This approach aims to determine the optimal furnace temperature curve,zone temperatures of the reflow oven,and the conveyor belt speed.
文摘This paper is concerned with the problem of finitetime control for a class of discrete-time networked systems.The measurement output and control input signals are quantized before being transmitted in communication network.The quantization density of the network is assumed to be variable depending on the throughputs of network for the sake of congestion avoidance.The variation of the quantization density modes satisfies persistent dwell-time(PDT)switching which is more general than dwell-time switching in networked channels.By using a quantization-error-dependent Lyapunov function approach,sufficient conditions are given to ensure that the quantized systems are finite-time stable and finite-time bounded with a prescribed H∞performance,upon which a set of controllers depending on the mode of quantization density are designed.In order to show the effectiveness of the designed H_∞controller,we apply the developed theoretical results to a numerical example.
基金supported by the National Natural Science Foundation of China(81672771 and 81871867 to C.X.)the Ministry of Science and Technology of the People’s Republic of China(2017YFA0504102 to D.P.)+1 种基金Tianjin Municipal Special Program of Talents Development for Excellent Youth ScholarsThe Chair of this National Key Research and Development Project(2017YFA0504102)is Duanqing Pei,and the corresponding author of this artical,Chenghao Xuan,is one of the members of the project.
文摘Epigenetics refers to how chromatin-associated factors and reversible chromatin modifications maintain DNA-based programs by regulating the chromatin structure(Strahl and Allis,2000).In recent years,genome sequencing studies of cancer have shown that genes encoding epigenetic factors are commonly mutated in cancer(Garraway and Lander,2013).Dys regulated,or mutant.
基金This work was supported by the National Natural Science Foundation of China(Grant No.52075221)the Research Foundation of Education Department of Jilin Province,China(Grant No.JJKH20231153KJ)the Fundamental Research Funds for the Central Universities(2019-2023).
文摘By imitating the body structure and movement mode of the crab in nature,a novel stick–slip piezo-driven positioning platform was proposed by employing the bionic flexible hinge mechanism with a symmetrical structure and two piezoelectric stacks.The structural design and bionic motion principle were discussed,followed by analyzing the feasibility,safety,and output magnification ratio of the bionic flexible hinge mechanism via the stiffness matrix method and finite element simulation.To investigate the output performances of the positioning platform,a prototype was fabricated and an experiment system was established.Stepping characteristics of the positioning platform under various driving voltages were characterized,and the results indicated that the positioning platform could move steadily under various driving voltages.Within 1 s,the differences between the forward and reverse output displacement were less than 3%under different driving frequencies,proving the high bidirectional motion symmetry.The maximum driving speed of 5.44 mm/s was obtained under the driving voltage of 120 V and driving frequency of 5 Hz.In addition,the carrying load capacity of the positioning platform was tested by standard weights,and the results showed that when the carrying load reached 10 N,the driving speed could still reach 60μm/s.