检索结果-内蒙古大学图书馆

6th Multiphase Flow Journey, JEM 2021

作者： Mastelari, Niederauer Rosa, Eugênio S. Mazza, Ricardo A. Leite, Jordan V. Faculty of Mechanical Engineering University of Campinas Campinas Brazil

ISBN: (纸本)9783030934552

Quick closing valve (QCV) is a widely applied technique in laboratory multiphase flow studies. It can be used as a reliable calibration method to pick up the volumetric fraction of the phases on the vertical column when the steady state of multiphase vertical streams is established. In laboratory Three-Phase Flow studies, thousands of trials are performed. Hence, it is suitable to automate QCV systems for holdup measurement. The automation improves costs, standardizes, and minimizes spending time with tiring repetitive measurements. This work presents the methodology and design of an automated QCV for Holdup measurement system for three-phase flow: air, kerosene, and water. For this, direct column heights measurements are obtained by an optical sensor precisely moved up/down. Furthermore, two pressure sensors are used to measure the weight of the three-phase column. Merging the data with the maximum likelihood estimation algorithm, the methodology and its uncertainties are presented. Data Fusion reduces uncertainties, making it possible to check inconsistencies and detect failures. Automated validation tests show that it is possible to accurately measure small columns of less than 1% of the total column. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Holdup measurement maximum likelihood estimation algorithm Multiphase flow systems Quick closing valves

来源：评论

学校读者我要写书评

暂无评论

Accuracy improvement of positioning data in greenhouse for agricultural machinery via optimisation algorithm

引用

JOURNAL OF ENGINEERING-JOE 2019年第15期2019卷 547-551页

作者： Geng, Jing Wang, Xiang Zhu, Saihua Lin, Xiangze Nanjing Agr Univ Coll Engn Dept Elect Engn Nanjing Jiangsu Peoples R China

Although several indoor positioning systems for greenhouse have been developed in automated agricultural machinery monitoring, the data measured by positioning systems still has large errors. In order to solve the problem, in this study, improved weighted-centroid algorithm and maximum likelihood estimation (MLE) algorithm were developed to optimise positioning data of agricultural machinery in the greenhouse, which is measured by ultra-wide band-based indoor positioning system according to different agricultural machinery working states. Compared with real coordinate data, when agricultural machinery stays still, the average static error of the data was 66.4 mm with the improved weighted-centroid algorithm;when the machinery is in dynamic state, the average dynamic error of the data was 61 mm and the probability that error <60 mm was 0.848 according to the MLE. Hence, the optimisation algorithms presented in this study improve the positioning accuracy significantly and the position of agricultural machinery is able to be estimated better compared with the raw data.

关键词： maximum likelihood estimation indoor communication agricultural machinery ultra wideband communication greenhouse automated agricultural machinery monitoring improved weighted-centroid algorithm maximum likelihood estimation algorithm ultra-wide band-based indoor positioning system average dynamic error optimisation algorithm raw data indoor positioning systems size 66 4 mm size 61 0 mm size 60 0 mm

来源：评论

学校读者我要写书评

暂无评论

Sparsity-aware multitarget localisation for distributed MIMO radar against phase synchronisation mismatch

引用

IET COMMUNICATIONS 2016年第17期10卷 2269-2275页

作者： Sun, Bin Chen, Haowen Zou, Huanxin Beijing Inst Tracking & Telecommun Technol Beijing 100094 Peoples R China Natl Univ Def Technol Coll Elect Sci & Engn Changsha 410073 Hunan Peoples R China

The authors address the problem of coherent multitarget localisation for distributed multiple-input multiple-output (MIMO) radar, in the presence of phase synchronisation mismatch between each transmitter-receiver pair. The inherent sparsity of targets in the surveillance area can be exploited to represent radar data and then target locations are accurately estimated using sparse reconstruction. However, due to the difficulty of perfect phase synchronisation, the localisation technique is usually required to eliminate the phase errors. This study jointly considers the phase error correction problem in the context of multitarget localisation. In this novel method, the direct position determination of multitarget is obtained by estimating the spare reflection coefficients and phase errors alternately. Numerical simulation results demonstrate that the authors' iterative block sparse Bayesian learning via maximum likelihood estimation algorithm obtains enhanced estimation accuracy against the phase synchronisation mismatch.

关键词： MIMO radar target tracking synchronisation radar transmitters radar receivers error correction belief networks learning (artificial intelligence) maximum likelihood estimation signal reconstruction radar signal processing sparsity-aware multitarget localisation distributed MIMO radar phase synchronisation mismatch coherent multitarget localisation distributed multiple-input multiple-output radar transmitter-receiver pair sparse reconstruction phase error elimination phase error correction problem direct position determination spare reflection coefficient estimation iterative block sparse Bayesian learning maximum likelihood estimation algorithm enhanced estimation accuracy

来源：评论

学校读者我要写书评

暂无评论

Research of R-A Hybrid Localization algorithm in Wireless Sensor Network

Research of R-A Hybrid Localization Algorithm in Wireless Se...

引用

2015 International Conference on Simulation, Modelling and Mathematical Statistics(SMMS 2015)

作者： Li-jun LIU Ya-chun WAN Institute of Information Science and Engineering Shenyang University of Technology

The research of positioning algorithm is an important work in wireless sensor *** In general the positioning algorithm of wireless sensor network can be divided into the positioning algorithm based on range and *** paper adopts R-A hybrid localization algorithm combining with the advantages and disadvantages of weighted maximum likelihood estimation algorithm based on RSSI and APIT *** the complementary characteristics of the localization algorithm based on range and range-free to complement each other and the positioning error of unknown nodes is reduced effectively.

关键词： Wireless sensor network maximum likelihood estimation algorithm APIT algorithm

来源：评论

学校读者我要写书评

暂无评论

An Assessment of OFDM Carrier Frequency Offset Synchronization Security for 4G Systems 33

An Assessment of OFDM Carrier Frequency Offset Synchronizati...

引用

33rd Annual IEEE Military Communications Conference on Affordable Mission Success - Meeting the Challenge (MILCOM)

作者： La Pan, Matthew J. Clancy, T. Charles McGwier, Robert W. Virginia Tech Elect & Comp Engn Blacksburg VA 24061 USA

ISBN: (纸本)9781479967704

Orthogonal Frequency Division Multiplexing (OFDM) is becoming widely deployed in fourth generation (4G) wireless communications systems. Synchronization between a transmitter and receiver is required for coherent demodulation of OFDM symbols, but this process is extremely fragile and susceptible to attacks from malicious third parties. Carrier frequency offset estimation and correction in particular is both prerequisite to demodulation and extremely sensitive to errors. In this work, we address security concerns and assess the performance of the popular maximum likelihood (ML) estimation algorithm developed in [1] in the presence of adversarial communications systems. We present performance metrics for OFDM frequency synchronization versus various physical attacks and assess key security improvements.

关键词： 4G mobile communication OFDM modulation demodulation maximum likelihood estimation radio receivers radio transmitters synchronisation telecommunication security 4G systems OFDM carrier frequency offset synchronization security OFDM frequency synchronization carrier frequency offset estimation coherent demodulation fourth generation wireless communications systems maximum likelihood estimation algorithm orthogonal frequency division multiplexing receiver transmitter Equations Frequency estimation Jamming OFDM Receivers Synchronization Transmitters

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：