Integrated navigation of GPS/INS based on fusion of recursive maximum likelihood IMM and Square-root Cubature Kalman filter
ISA TRANSACTIONS
Authors: Song, Rui; Chen, Xiyuan; Fang, Yongchun; Huang, Haoqian
Abstract
Information fusion of the GPS/INS integrated system is always related to characteristics of the inertial system and the sensor feature, yet prior knowledge is still difficult to obtain in real applications. To deal with the uncertainty of error covariance and state noise in vehicle navigation, this paper presents a novel approach, wherein the integration of Square-root Cubature Kalman Filters (SCKF) and Interacting Multiple Model (IMM) are also introduced. In the framework of IMM, the SCKFs with different covariance are designed to reflect various vehicle dynamics. Besides, since the IMM-SCKF can switch flexibly among the filters, the transition probability matrix is computed with maximum likelihood method to adapt to different noise characteristics. The performance of the proposed algorithm is guaranteed by theoretical analyses, and a series of vehicular experiments with different maneuvers are carried out in an urban environment. The results indicate that, in comparison with the CKF and the IMM-CKF, the accuracy of velocity and attitude are increased by the proposed strategy. (C) 2020 ISA. Published by Elsevier Ltd. All rights reserved.
Uncovering candidate genes responsive to salt stress in Salix matsudana (Koidz) by transcriptomic analysis
PLOS ONE
Authors: Chen, Yanhong; Jiang, Yuna; Chen, Yu; Feng, Wenxiang; Liu, Guoyuan; Yu, Chunmei; Lian, Bolin; Zhong, Fei; Zhang, Jian
Abstract
Salix matsudana, a member ofSalicaceae, is an important ornamental tree in China. Because of its capability to tolerate high salt conditions,S.matsudanaalso plays an important ecological role when grown along Chinese coastal beaches, where the salinity content is high. Here, we aimed to elucidate the mechanism of higher salt tolerance inS.matsudanavariety '9901' by identifying the associated genes through RNA sequencing and comparing differential gene expression between theS.matsudanasalt-tolerant and salt-sensitive samples treated with 150 mM NaCl. Transcriptomic comparison of the roots of the two samples revealed 2174 and 3159 genes responsive to salt stress in salt-sensitive and salt-tolerant sample, respectively. Real-time polymerase chain reaction analysis of 9 of the responsive genes revealed a strong, positive correlation with RNA sequencing data. The genes were enriched in several pathways, including carbon metabolism pathway, plant-pathogen interaction pathway, and plant hormone signal transduction pathway. Differentially expressed genes (DEGs) encoding transcription factors associated with abiotic stress responses and salt stress response network were identified; their expression levels differed between the two samples in response to salt stress. Hub genes were also revealed by weighted gene co-expression network (WGCNA) analysis. For functional analysis of the DEG encoding sedoheptulose-1,7-bisphosphatase (SBPase), the gene was overexpressed in transgenicArabidopsis, resulting in increased photosynthetic rates, sucrose and starch accumulation, and enhanced salt tolerance. Further functional characterization of other hub DEGs will reveal the molecular mechanism of salt tolerance inS.matsudanaand allow the application ofS.matsudanain coastal afforestation.