为了解决冷链物流存在的运输效率低、冷藏箱设备利用率低等问题,设计了一种基于窄带物联网技术的冷藏箱共享系统。系统利用RFID(Radio Frequency IDentification)技术、传感器技术、多模卫星定位技术,采用多层次分布结构,把硬件搭载于...为了解决冷链物流存在的运输效率低、冷藏箱设备利用率低等问题,设计了一种基于窄带物联网技术的冷藏箱共享系统。系统利用RFID(Radio Frequency IDentification)技术、传感器技术、多模卫星定位技术,采用多层次分布结构,把硬件搭载于子母箱体上,配合云数据库以及良好的人机交互平台,实现了冷藏箱组的共享。这种共享模式采用信用分制度,实现了自助预约、自助租赁、自助结算以及订单追溯等功能,可有效提高冷链运输效率、实现运输过程监控、降低冷链设备闲置率。展开更多
In order to improve the process precision of an XY laser annealing table, a geometric error modeling, and an identification and compensation method were proposed. Based on multi-body system theory, a geometric error m...In order to improve the process precision of an XY laser annealing table, a geometric error modeling, and an identification and compensation method were proposed. Based on multi-body system theory, a geometric error model for the laser annealing table was established. It supports the identification of 7 geometric errors affecting the annealing accuracy. An original identification method was presented to recognize these geometric errors. Positioning errors of 5 lines in the workspace were measured by a laser interferometer, and the 7 geometric errors were identified by the proposed algorithm. Finally, a software-based error compensation method was adopted, and a compensation mechanism was developed in a postprocessor based on LabVIEW. The identified geometric errors can be compensated by converting ideal NC codes to actual NC codes. A validation experiment has been conducted on the laser annealing table, and the results indicate that positioning errors of two validation lines decreased from ±37 μm and ±33 μm to ±5 μm and ±4.5 μm, respectively. The geometric error modeling, identification and compensation method presented in this work can be straightforwardly extended to any configurations of 2-dimensional worktable.展开更多
The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television...The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television de Catalunya, which is intended to disseminate computer concepts, tools and procedures. In this kind of program, one can find spoken language （on/off screen voices, interviews, etc.）, other oral material （sounds, music, songs）, written language （descriptions, title sequences, inserts and Uniform Resource Locator, or electronic addresses）, and other visual material （film cut images, advertising, other TV programs, cartoons, films, both location or studio images, depicting reality, or computer screens, or logotypes）. The profusion of multimodal elements used in this program helps to keep the young audience＇s attention. The use of references to their world or knowledge, as a target group, is based on interplay among different semiotic strategies. At the same time, the entire program＇s multi-segmentation into short video clips, combined with a fast paced sound track helps its audience to understand the specialized explanations presented. Of all the multimodal wealth that the program presents, we will concentrate only on the relationship between the words and the images （leaving other secondary semiotics to one side）, the main strategy for achieving the objective of transmitting knowledge and winning adolescent audiences.展开更多
With the development of the Ground Positioning System (GPS) modernization and the expectable implementation of Galileo, people pay more and more attention to civil applications on multi-frequency signals. This paper p...With the development of the Ground Positioning System (GPS) modernization and the expectable implementation of Galileo, people pay more and more attention to civil applications on multi-frequency signals. This paper proposes a new and advanced positioning algorithm for the dual-frequency satellite navigation receivers, concerning the various influences of all the ranging error sources and taking advantage of the Klobuchar single-frequency ionospheric model. The paper also presents positioning precision provided by the new algorithm. Theoretical analysis and experimental results show that, the new dual-frequency positioning algorithm can achieve higher positioning accu- racy than the single-frequency positioning algorithm and the traditional dual-frequency positioning algorithm.展开更多
针对单系统在遮挡环境下可见卫星数较少、历元利用率低、定位稳定性、定位可靠性和定位精度较差的问题,首先,利用间接平差法对BDS/GPS/GLONASS/Galileo组合观测方程进行求解;然后,运用最小二乘法原理求解待估参数,最终解算出测站点坐标...针对单系统在遮挡环境下可见卫星数较少、历元利用率低、定位稳定性、定位可靠性和定位精度较差的问题,首先,利用间接平差法对BDS/GPS/GLONASS/Galileo组合观测方程进行求解;然后,运用最小二乘法原理求解待估参数,最终解算出测站点坐标。采用MGEX站部分测站的数据对不同截止高度角下(7°、15°、20°、30°、40°、45°)不同模式GPS、GPS+Galileo、GPS+GLONASS、BDS+GLONASS+Galileo、GPS+BDS、GPS+GLONASS+BDS、GPS+GLONASS+BDS+Galileo的单点定位(single point positioning,SPP)进行解算和数据处理。结果表明,在截止高度角为45°时,点位离散程度变差,但相比其他模式特别是GPS单系统,GPS+GLONASS+BDS+Galileo组合稳定性和可靠性都较好;GPS单系统历元利用率较低,全天不足1/3,然而GPS+BDS、GPS+GLONASS+BDS、GPS+GLONASS+BDS+Galileo组合历元仍然全天可用,GPS部分历元精度优于GPS+GLONASS+BDS和GPS+GLONASS+BDS+Galileo组合,但整体定位性能较差。GRCE组合在全天历元可用和实现单点定位前提下,整体定位性能优于其他模式。展开更多
In this work, we analyzed time-series and trends of the tropical belt edges and widths with three methods based on the tropopause using new global positioning system radio occultation(GPS RO) data from the Constellati...In this work, we analyzed time-series and trends of the tropical belt edges and widths with three methods based on the tropopause using new global positioning system radio occultation(GPS RO) data from the Constellation Observing System for Meteorology, Ionosphere, and Climate(COSMIC) mission for September 2006–February 2014. The results from the three methods agreed well with previous studies and new features were found. To avoid the El Ni?o Southern Oscillation(ENSO) and Quasi-Biennial Oscillation(QBO) influence, we applied a simple multiple linear regression model to the monthly anomalies to obtain the tropical belt edges and width trends. During the study, we found equatorward movements of the tropical belt edges on both hemispheres. The narrowing of the tropical belt mainly occurred in the Pacific Ocean. We also found that the deseasonalized monthly anomalies of the tropical belt width were closely related with the ENSO and QBO. The tropical belt at a height of 15 km was mostly closely related with the ENSO. The correlations between the QBO and the tropical belt were consistent for the three methods.展开更多
文摘为了解决冷链物流存在的运输效率低、冷藏箱设备利用率低等问题,设计了一种基于窄带物联网技术的冷藏箱共享系统。系统利用RFID(Radio Frequency IDentification)技术、传感器技术、多模卫星定位技术,采用多层次分布结构,把硬件搭载于子母箱体上,配合云数据库以及良好的人机交互平台,实现了冷藏箱组的共享。这种共享模式采用信用分制度,实现了自助预约、自助租赁、自助结算以及订单追溯等功能,可有效提高冷链运输效率、实现运输过程监控、降低冷链设备闲置率。
基金Projects(2012ZX04010-011,2009ZX02037-02) supported by the Key National Science and Technology Project of China
文摘In order to improve the process precision of an XY laser annealing table, a geometric error modeling, and an identification and compensation method were proposed. Based on multi-body system theory, a geometric error model for the laser annealing table was established. It supports the identification of 7 geometric errors affecting the annealing accuracy. An original identification method was presented to recognize these geometric errors. Positioning errors of 5 lines in the workspace were measured by a laser interferometer, and the 7 geometric errors were identified by the proposed algorithm. Finally, a software-based error compensation method was adopted, and a compensation mechanism was developed in a postprocessor based on LabVIEW. The identified geometric errors can be compensated by converting ideal NC codes to actual NC codes. A validation experiment has been conducted on the laser annealing table, and the results indicate that positioning errors of two validation lines decreased from ±37 μm and ±33 μm to ±5 μm and ±4.5 μm, respectively. The geometric error modeling, identification and compensation method presented in this work can be straightforwardly extended to any configurations of 2-dimensional worktable.
文摘The aim of this work is to study the interaction of spoken words and images that are used within programs targeted to popularize knowledge among teenagers. We will look into the program Bit@bit developed by Television de Catalunya, which is intended to disseminate computer concepts, tools and procedures. In this kind of program, one can find spoken language （on/off screen voices, interviews, etc.）, other oral material （sounds, music, songs）, written language （descriptions, title sequences, inserts and Uniform Resource Locator, or electronic addresses）, and other visual material （film cut images, advertising, other TV programs, cartoons, films, both location or studio images, depicting reality, or computer screens, or logotypes）. The profusion of multimodal elements used in this program helps to keep the young audience＇s attention. The use of references to their world or knowledge, as a target group, is based on interplay among different semiotic strategies. At the same time, the entire program＇s multi-segmentation into short video clips, combined with a fast paced sound track helps its audience to understand the specialized explanations presented. Of all the multimodal wealth that the program presents, we will concentrate only on the relationship between the words and the images （leaving other secondary semiotics to one side）, the main strategy for achieving the objective of transmitting knowledge and winning adolescent audiences.
文摘With the development of the Ground Positioning System (GPS) modernization and the expectable implementation of Galileo, people pay more and more attention to civil applications on multi-frequency signals. This paper proposes a new and advanced positioning algorithm for the dual-frequency satellite navigation receivers, concerning the various influences of all the ranging error sources and taking advantage of the Klobuchar single-frequency ionospheric model. The paper also presents positioning precision provided by the new algorithm. Theoretical analysis and experimental results show that, the new dual-frequency positioning algorithm can achieve higher positioning accu- racy than the single-frequency positioning algorithm and the traditional dual-frequency positioning algorithm.
文摘针对单系统在遮挡环境下可见卫星数较少、历元利用率低、定位稳定性、定位可靠性和定位精度较差的问题,首先,利用间接平差法对BDS/GPS/GLONASS/Galileo组合观测方程进行求解;然后,运用最小二乘法原理求解待估参数,最终解算出测站点坐标。采用MGEX站部分测站的数据对不同截止高度角下(7°、15°、20°、30°、40°、45°)不同模式GPS、GPS+Galileo、GPS+GLONASS、BDS+GLONASS+Galileo、GPS+BDS、GPS+GLONASS+BDS、GPS+GLONASS+BDS+Galileo的单点定位(single point positioning,SPP)进行解算和数据处理。结果表明,在截止高度角为45°时,点位离散程度变差,但相比其他模式特别是GPS单系统,GPS+GLONASS+BDS+Galileo组合稳定性和可靠性都较好;GPS单系统历元利用率较低,全天不足1/3,然而GPS+BDS、GPS+GLONASS+BDS、GPS+GLONASS+BDS+Galileo组合历元仍然全天可用,GPS部分历元精度优于GPS+GLONASS+BDS和GPS+GLONASS+BDS+Galileo组合,但整体定位性能较差。GRCE组合在全天历元可用和实现单点定位前提下,整体定位性能优于其他模式。
基金supported by the National Natural Science Foundation of China(Grant No.41374036)the National Key Basic Research Program of China(Grant No.2013CB733301)+1 种基金the Funds for Innovative Research Groups of the National Natural Science Foundation of China(Grant No.41021061)the Fundamental Research Funds for the Central Universities
文摘In this work, we analyzed time-series and trends of the tropical belt edges and widths with three methods based on the tropopause using new global positioning system radio occultation(GPS RO) data from the Constellation Observing System for Meteorology, Ionosphere, and Climate(COSMIC) mission for September 2006–February 2014. The results from the three methods agreed well with previous studies and new features were found. To avoid the El Ni?o Southern Oscillation(ENSO) and Quasi-Biennial Oscillation(QBO) influence, we applied a simple multiple linear regression model to the monthly anomalies to obtain the tropical belt edges and width trends. During the study, we found equatorward movements of the tropical belt edges on both hemispheres. The narrowing of the tropical belt mainly occurred in the Pacific Ocean. We also found that the deseasonalized monthly anomalies of the tropical belt width were closely related with the ENSO and QBO. The tropical belt at a height of 15 km was mostly closely related with the ENSO. The correlations between the QBO and the tropical belt were consistent for the three methods.
