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Static and dynamic evaluations of acoustic positioning system using TDMA and FDMA for robots operating in a greenhouse

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International Journal of Agricultural and Biological Engineering 2022年第5期15卷 28-33页

作者： Lok Wai Jacky Tsay Tomoo Shiigi xunyue zhao Zichen Huang Keiichiro Shiraga Tetsuhito Suzuki Yuichi Ogawa Naoshi Kondo Laboratory of Bio-Sensing Engineering Division of Environmental Science and TechnologyGraduate School of AgricultureKyoto UniversityKyoto 606-8502Japan Department of Ocean Mechanical Engineering National Fisheries UniversityShimonoseki 759-6595Japan

Acoustic positioning system has great potential to be applied in a greenhouse due to its centimeter-level accuracy,low cost,and ability of extensive greenhouse *** Spectrum Sound-based local positioning system(SSSLPS)was proposed to be a navigation tool for multiple agricultural robots by the authors'research ***,to increase the system capacity for positioning multiple robots in a greenhouse,the near-far problem caused by the interference between speakers needs to be *** use of different access methods,Time Division Multiple Access(TDMA)or Frequency Division Multiple Access(FDMA),is essential in the SSSLPS system for solving the near-far *** static positioning in a greenhouse was first evaluated by setting different parameters to determine the optimal signal setting for a dynamic *** that,the moving robot tests were added with a motion capture system and tested the performance of TDMA and *** results demonstrated that TDMA can be used in a stationary sound-based positioning system with 12.2 mm accuracy,but it has a time delay problem in dynamic positioning.A simulation was designed to mimic the position error increases with different moving *** FDMA has the sound damping problem in high-frequency regions creating a peak detection issue,it achieved a higher accuracy with an average position error of 62.1 mm compared to 180.3 mm of *** study shows that the TDMA method is suitable for static measurements,while the FDMA method is suitable for measuring dynamic objects and controlling mobile robots.

关键词： greenhouse robots positioning system near-far problem TDMA FDMA

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数字普惠金融对小微企业全要素生产率的影响——“锦上添花”还是“雪中送炭”

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南京社会科学 2021年第12期 35-47页

作者：顾宁吴懋赵勋悦吉林大学数量经济研究中心长春130012 西北大学经济管理学院西安710127 吉林大学农村金融研究中心长春130012

本研究利用中国小微企业调查(CMES)数据,采用Cross-section Weights固定效应模型考察了数字普惠金融发展对小微企业全要素生产率的影响,并进一步以融资约束为中介变量考察这种影响路径的非线性中介效应。实证分析表明:数字普惠金融发展... 详细信息

本研究利用中国小微企业调查(CMES)数据,采用Cross-section Weights固定效应模型考察了数字普惠金融发展对小微企业全要素生产率的影响,并进一步以融资约束为中介变量考察这种影响路径的非线性中介效应。实证分析表明:数字普惠金融发展显著促进了小微企业全要素生产率的提升,但是这一影响结果具有异质性,在经济发达地区、中东部地区、规模较大的小微企业中,提升效果更为显著;数字普惠金融发展缓解了小微企业融资约束,而融资约束的缓解对小微企业全要素生产率的提升具有非线性影响;从融资约束角度来看,数字普惠金融对小微企业全要素生产率的提升起到了"雪中送炭"的作用,当企业处于相对较高融资约束水平时,数字普惠金融通过缓解融资约束来促进全要素生产率的作用效果较为明显,随着小微企业融资约束的进一步缓解,这种作用效果会递减,在较低融资约束水平时表现为抑制作用。

关键词：数字普惠金融小微企业全要素生产率融资约束

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