“精灵圈”是海岸带盐沼植被生态系统中的一种“空间自组织”结构,对盐沼湿地的生产力、稳定性和恢复力有重要影响。无人机影像是实现“精灵圈”空间位置高精度识别及解译其时空演化趋势与规律的重要数据源,但“精灵圈”像素与背景像素...“精灵圈”是海岸带盐沼植被生态系统中的一种“空间自组织”结构,对盐沼湿地的生产力、稳定性和恢复力有重要影响。无人机影像是实现“精灵圈”空间位置高精度识别及解译其时空演化趋势与规律的重要数据源,但“精灵圈”像素与背景像素在色彩信息和外形特征上差异较小,如何从二维影像中智能精准地识别“精灵圈”像素并对识别的单个像素形成个体“精灵圈”是目前的技术难点。本文提出了一种结合分割万物模型(Segment Anything Model,SAM)视觉分割模型与随机森林机器学习的无人机影像“精灵圈”分割及分类方法,实现了单个“精灵圈”的识别和提取。首先,通过构建索伦森-骰子系数(S?rensen-Dice coefficient,Dice)和交并比(Intersection over Union,IOU)评价指标,从SAM中筛选预训练模型并对其参数进行优化,实现全自动影像分割,得到无属性信息的分割掩码/分割类;然后,利用红、绿、蓝(RGB)三通道信息及空间二维坐标将分割掩码与原图像进行信息匹配,构造分割掩码的特征指标,并根据袋外数据(Out of Bag,OOB)误差减小及特征分布规律对特征进行分析和筛选;最后,利用筛选的特征对随机森林模型进行训练,实现“精灵圈”植被、普通植被和光滩的自动识别与分类。实验结果表明:本文方法“精灵圈”平均正确提取率96.1%,平均错误提取率为9.5%,为精准刻画“精灵圈”时空格局及海岸带无人机遥感图像处理提供了方法和技术支撑。展开更多
Recently,Meta AI Research approaches a general,promptable segment anything model(SAM)pre-trained on an unprecedentedly large segmentation dataset(SA-1B).Without a doubt,the emergence of SAM will yield significant bene...Recently,Meta AI Research approaches a general,promptable segment anything model(SAM)pre-trained on an unprecedentedly large segmentation dataset(SA-1B).Without a doubt,the emergence of SAM will yield significant benefits for a wide array of practical image segmentation applications.In this study,we conduct a series of intriguing investigations into the performance of SAM across various applications,particularly in the fields of natural images,agriculture,manufacturing,remote sensing and healthcare.We analyze and discuss the benefits and limitations of SAM,while also presenting an outlook on its future development in segmentation tasks.By doing so,we aim to give a comprehensive understanding of SAM's practical applications.This work is expected to provide insights that facilitate future research activities toward generic segmentation.Source code is publicly available at https://github.com/LiuTingWed/SAM-Not-Perfect.展开更多
In order to alleviate unstable factor-caused bifurcation and reduce oscillations in traffic flow,a feedback control with consideration of time delay is designed for the solid angle model(SAM).The stability and bifurca...In order to alleviate unstable factor-caused bifurcation and reduce oscillations in traffic flow,a feedback control with consideration of time delay is designed for the solid angle model(SAM).The stability and bifurcation condition of the new SAM is derived through linear analysis and bifurcation analysis,and then accurate range of stable region is obtained.In order to explore the mechanism of the influence of multiple parameter combinations on the stability of controlled systems,a definite integral stabilization method is provided to determine the stable interval of time delay and feedback gain.Numerical simulations are explored to verify the feasibility and effectiveness of the proposed model,which also demonstrate that feedback gain and delay are two key factors to alleviate traffic congestion in the SAM.展开更多
为了研究出行者对旅游出行服务的使用意向,基于出行即服务(mobility as a service, MaaS)环境考虑心理需求构建了服务接受模型(service acceptance model, SAM)。通过网络问卷调查方法获取MaaS影响因素的主观评价数据,基于结构方程模型...为了研究出行者对旅游出行服务的使用意向,基于出行即服务(mobility as a service, MaaS)环境考虑心理需求构建了服务接受模型(service acceptance model, SAM)。通过网络问卷调查方法获取MaaS影响因素的主观评价数据,基于结构方程模型检验了SAM的假设及其内部一致性、可靠性、收敛效度和判别效度。结果表明:感知有用性对出行者使用意向的正向影响最大,感知易用性次之,而感知风险呈负向作用;感知有用性和感知易用性影响出行者的习惯模式一致性,进而间接影响出行者使用意向;心理需求满足对使用意向具有重要作用,出行者的自主性、能力、关联性及利他性等心理需求因素影响感知有用性、感知易用性和感知风险,进而间接影响出行者使用意向;SAM可有效地描述旅游出行服务使用意向,并为异质性出行者在制定精细化、差异化策略时提供支持。展开更多
Concentrated solar power plants can play a significant role in alleviating Sudan’s energy crisis.These plants can be established and implemented in Sudan,as their potential is considerably high due to the climate con...Concentrated solar power plants can play a significant role in alleviating Sudan’s energy crisis.These plants can be established and implemented in Sudan,as their potential is considerably high due to the climate conditions in Sudan.This study investigates the design of a parabolic trough concentrated solar power plant in Sudan and analyzes its technical and economic feasibility.The simulation of the plant’s model used System Advisor Model(SAM)software.To determine the best location for the construction of the plant,data from 15 cities in Sudan were compared with each other based on their solar radiation and land properties.Wadi Halfa,a city in the northern region of Sudan,was chosen as the location due to its good topographical properties and climate conditions.The results show that the proposed plant can generate 281.145 GWh of electricity annually with a capacity factor of 40.1%and an overall efficiency of 15%.Additionally,a simple cost analysis of the plant indicates a levelized cost of electricity of 0.155$/kWh.As the study results are consistent with the characteristics of similar plants,the proposed plant is considered technically and economically feasible under the conditions at its location.展开更多
文摘“精灵圈”是海岸带盐沼植被生态系统中的一种“空间自组织”结构,对盐沼湿地的生产力、稳定性和恢复力有重要影响。无人机影像是实现“精灵圈”空间位置高精度识别及解译其时空演化趋势与规律的重要数据源,但“精灵圈”像素与背景像素在色彩信息和外形特征上差异较小,如何从二维影像中智能精准地识别“精灵圈”像素并对识别的单个像素形成个体“精灵圈”是目前的技术难点。本文提出了一种结合分割万物模型(Segment Anything Model,SAM)视觉分割模型与随机森林机器学习的无人机影像“精灵圈”分割及分类方法,实现了单个“精灵圈”的识别和提取。首先,通过构建索伦森-骰子系数(S?rensen-Dice coefficient,Dice)和交并比(Intersection over Union,IOU)评价指标,从SAM中筛选预训练模型并对其参数进行优化,实现全自动影像分割,得到无属性信息的分割掩码/分割类;然后,利用红、绿、蓝(RGB)三通道信息及空间二维坐标将分割掩码与原图像进行信息匹配,构造分割掩码的特征指标,并根据袋外数据(Out of Bag,OOB)误差减小及特征分布规律对特征进行分析和筛选;最后,利用筛选的特征对随机森林模型进行训练,实现“精灵圈”植被、普通植被和光滩的自动识别与分类。实验结果表明:本文方法“精灵圈”平均正确提取率96.1%,平均错误提取率为9.5%,为精准刻画“精灵圈”时空格局及海岸带无人机遥感图像处理提供了方法和技术支撑。
基金supported by the Mitacs,CFI-JELF and NSERC Discovery grants.
文摘Recently,Meta AI Research approaches a general,promptable segment anything model(SAM)pre-trained on an unprecedentedly large segmentation dataset(SA-1B).Without a doubt,the emergence of SAM will yield significant benefits for a wide array of practical image segmentation applications.In this study,we conduct a series of intriguing investigations into the performance of SAM across various applications,particularly in the fields of natural images,agriculture,manufacturing,remote sensing and healthcare.We analyze and discuss the benefits and limitations of SAM,while also presenting an outlook on its future development in segmentation tasks.By doing so,we aim to give a comprehensive understanding of SAM's practical applications.This work is expected to provide insights that facilitate future research activities toward generic segmentation.Source code is publicly available at https://github.com/LiuTingWed/SAM-Not-Perfect.
基金supported by the National Key Research and Development Program of China(No.2017YFE9134700)the Natural Science Foundation of Zhejiang Province,China(No.LY22G010001)+3 种基金the Program of Humanities and Social Science of Education Ministry of China(No.20YJA630008)the Ningbo Natural Science Foundation of China(Nos.2021J235 and 2021J111)the Fund of Healthy&Intelligent Kitchen Engineering Research Center of Zhejiang Provincethe K.C.Wong Magna Fund in Ningbo University,China.
文摘In order to alleviate unstable factor-caused bifurcation and reduce oscillations in traffic flow,a feedback control with consideration of time delay is designed for the solid angle model(SAM).The stability and bifurcation condition of the new SAM is derived through linear analysis and bifurcation analysis,and then accurate range of stable region is obtained.In order to explore the mechanism of the influence of multiple parameter combinations on the stability of controlled systems,a definite integral stabilization method is provided to determine the stable interval of time delay and feedback gain.Numerical simulations are explored to verify the feasibility and effectiveness of the proposed model,which also demonstrate that feedback gain and delay are two key factors to alleviate traffic congestion in the SAM.
文摘为了研究出行者对旅游出行服务的使用意向,基于出行即服务(mobility as a service, MaaS)环境考虑心理需求构建了服务接受模型(service acceptance model, SAM)。通过网络问卷调查方法获取MaaS影响因素的主观评价数据,基于结构方程模型检验了SAM的假设及其内部一致性、可靠性、收敛效度和判别效度。结果表明:感知有用性对出行者使用意向的正向影响最大,感知易用性次之,而感知风险呈负向作用;感知有用性和感知易用性影响出行者的习惯模式一致性,进而间接影响出行者使用意向;心理需求满足对使用意向具有重要作用,出行者的自主性、能力、关联性及利他性等心理需求因素影响感知有用性、感知易用性和感知风险,进而间接影响出行者使用意向;SAM可有效地描述旅游出行服务使用意向,并为异质性出行者在制定精细化、差异化策略时提供支持。
文摘Concentrated solar power plants can play a significant role in alleviating Sudan’s energy crisis.These plants can be established and implemented in Sudan,as their potential is considerably high due to the climate conditions in Sudan.This study investigates the design of a parabolic trough concentrated solar power plant in Sudan and analyzes its technical and economic feasibility.The simulation of the plant’s model used System Advisor Model(SAM)software.To determine the best location for the construction of the plant,data from 15 cities in Sudan were compared with each other based on their solar radiation and land properties.Wadi Halfa,a city in the northern region of Sudan,was chosen as the location due to its good topographical properties and climate conditions.The results show that the proposed plant can generate 281.145 GWh of electricity annually with a capacity factor of 40.1%and an overall efficiency of 15%.Additionally,a simple cost analysis of the plant indicates a levelized cost of electricity of 0.155$/kWh.As the study results are consistent with the characteristics of similar plants,the proposed plant is considered technically and economically feasible under the conditions at its location.
