112 results on '"Dingjie, Wang"'
Search Results
2. Spatial-Temporal Super-Resolution of Satellite Imagery via Conditional Pixel Synthesis.
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Yutong He, Dingjie Wang, Nicholas Lai, William Zhang, Chenlin Meng, Marshall Burke, David B. Lobell, and Stefano Ermon
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- 2021
3. Self-Assembling Peptide RADA16 Nanofiber Scaffold Hydrogel-Wrapped Concentrated Growth Factors in Osteogenesis of MC3T3
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Renjie Yang, Jiali Chen, Dingjie Wang, Yichen Xu, and Guomin Ou
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alveolar bone cleft ,alveolar bone grafting ,RADA16 ,CGFs ,osteogenesis ,Biotechnology ,TP248.13-248.65 ,Medicine (General) ,R5-920 - Abstract
Concentrated growth factors (CGFs) are widely used in surgery with bone grafting, but the release of growth factors from CGFs is rapid. RADA16, a self-assembling peptide, can form a scaffold that is similar to the extracellular matrix. Based on the properties of RADA16 and CGF, we hypothesized that the RADA16 nanofiber scaffold hydrogel could enhance the function of CGFs and that the RADA16 nanofiber scaffold hydrogel-wrapped CGFs (RADA16-CGFs) would perform a good osteoinductive function. This study aimed to investigate the osteoinductive function of RADA16-CGFs. Scanning electron microscopy, rheometry, and ELISA were performed, and MC3T3-E1 cells were used to test cell adhesion, cytotoxicity, and mineralization after administration with RADA16-CGFs. We found that RADA16 endowed with the sustained release of growth factors from CGFs, which can help maximize the function of CGFs in osteoinduction. The application of the atoxic RADA16 nanofiber scaffold hydrogel with CGFs can be a new therapeutic strategy for the treatment of alveolar bone loss and other problems that require bone regeneration.
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- 2023
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4. Tensor-based mathematical framework and new centralities for temporal multilayer networks.
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Dingjie Wang, Wei Yu 0009, and Xiufen Zou
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- 2020
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5. Constrained MEMS-Based GNSS/INS Tightly Coupled System With Robust Kalman Filter for Accurate Land Vehicular Navigation.
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Dingjie Wang, Yi Dong, Zhaoyang Li, Qingsong Li, and Jie Wu
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- 2020
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6. Adhesive Property of 3D-Printed PEEK Abutments: Effects of Surface Treatment and Temporary Crown Material on Shear Bond Strength
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Dingjie Wang, Xingting Han, Feng Luo, Florian M. Thieringer, Yichen Xu, Guomin Ou, and Sebastian Spintzyk
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fused filament fabrication ,polyether ether ketone ,additive manufacturing ,shear bond strength ,temporary abutment ,dental implantology ,Biotechnology ,TP248.13-248.65 ,Medicine (General) ,R5-920 - Abstract
Three-dimensionally printed polyetheretherketone (PEEK) materials are promising for fabricating customized dental abutments. This study aimed to investigate the adhesive property of a 3D-printed PEEK material. The effects of surface treatment and temporary crown materials on shear bond strength were evaluated. A total of 108 PEEK discs were 3D printed by fused-filament fabrication. Surface treatments, including sandblasting, abrasive paper grinding, and CO2 laser ablation, were applied to the PEEK discs, with the untreated specimens set as the control. Afterward, the surface topographies of each group were investigated by scanning electron microscopy (SEM, n = 1) and roughness measurements (n = 7). After preparing the bonding specimens with three temporary crown materials (Artificial teeth resin (ATR), 3M™ Filtek™ Supreme Flowable Restorative (FR), and Cool Temp NATURAL (CTN)), the shear bond strength was measured (n = 6), and the failure modes were analyzed by microscopy and SEM. The results showed that ATR exhibited a significantly higher shear bond strength compared to FR and CTN (p < 0.01), and the PEEK surfaces treated by sandblasting and abrasive paper grinding showed a statistically higher shear bond strength compared to the control (p < 0.05). For clinical application, the ATR material and subtractive surface treatments are recommended for 3D-printed PEEK abutments.
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- 2022
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7. Control of multilayer biological networks and applied to target identification of complex diseases.
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Wei Zheng, Dingjie Wang, and Xiufen Zou
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- 2019
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8. Real-Time Precise DGNSS/INS Integrated Relative Positioning with High Output Rate and Low Broadcast Rate for Kinematic-to-Kinematic Applications
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Qingsong Li, Yi Dong, Dingjie Wang, Jie Wu, and Liang Zhang
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DGNSS/INS integrated ,high output rate ,precise relative positioning ,low bit rate ,kinematic-to-kinematic ,Science - Abstract
High-output-rate relative positions are required for high-speed safety-critical kinematic-to-kinematic applications such as pre-crash sensing and shipboard landing. We propose a real-time, high-output-rate relative positioning method based on the integration of a real time kinematic (RTK) differential global navigation satellite systems (DGNSS) relative positioning algorithm, carrier-phase-based tightly coupled GNSS/Inertial navigation system (TC-GNSS/INS) integration algorithm and polynomial prediction algorithm for position increment. We focus on the rarely studied issue that data broadcast rates and sampling rates have effects on the integrated relative positioning accuracy under different motion states of a moving base. A vehicle-to-vehicle field test with a frequently turning base demonstrates the advantages of the proposed method, such as low bit rate of broadcast data, high output rate of position solutions and excellent real-time tolerance of latency. The results show that compared with the 10-Hz output of sole RTK DGNSS relative positioning, the proposed method can provide centimeter-level-accuracy relative positions at an output rate of 125 Hz with a sampling rate of 1 Hz, and the bit rate can be reduced by 83.12%. A UAV-to-boat field test with straight-line-motion moving base is then carried out to validate the applicability of the proposed system for aircraft applications. The results show that the broadcast rate of position increments of the moving base can be further reduced.
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- 2022
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9. Multiple deep neural networks with multiple labels for cross-modal hashing retrieval.
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Yicai Xie, Xianhua Zeng, Tinghua Wang, Liming Xu, and Dingjie Wang
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- 2022
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10. Trajectory Control in Nonlinear Networked Systems and Its Applications to Complex Biological Systems.
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Suoqin Jin, Dingjie Wang, and Xiufen Zou
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- 2018
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11. Using Multi-Antenna Trajectory Constraint to Analyze BeiDou Carrier-Phase Observation Error of Dynamic Receivers
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Chenyao Xiong, Qingsong Li, Dingjie Wang, and Jie Wu
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GNSS ,dynamic receiver ,error bounding ,integrity monitoring ,characteristic analysis ,Chemical technology ,TP1-1185 - Abstract
Appropriate cycle-slip and measurement-error models are essential for BeiDou carrier-phase-based integrity risk calculation. To establish the receiver’s measurement-error model, an accurate position reference of the GNSS antenna is fundamental for calculating the measurement error. However, it is still a challenge to acquire position references for dynamic BeiDou receivers, resulting in improper GNSS measurement-error models and unreliable integrity monitoring. This paper proposes an improved precise relative positioning scheme by adopting multi-antenna trajectory constraints for dynamic BeiDou receivers. The dynamic experiments show an obvious decline of 78.7%, at most, in the positioning failure rate of the proposed method, as compared with the traditional method. The position solutions obtained from the proposed approach are used as the reference to analyze the cycle-slip and measurement-error characteristics of the dynamic receiver. The field test results indicate that the cycle-slip rate decreases with the increase of signal-to-noise ratio (SNR), and cycle slipping obeys a positively skewed distribution that could be fitted by the Gaussian mixture model (GMM). On the other hand, the standard deviation of the carrier-phase measurement error is inversely proportional to SNR, and its distribution is characteristically fat-tailed, which could be fitted by the bi-normal model.
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- 2021
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12. Control Energy and controllability of multilayer Networks.
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Dingjie Wang and Xiufen Zou
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- 2017
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13. A High-Accuracy SINS/RCNS Integrated Navigation Algorithm
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Yi Zhao, Dingjie Wang, Hongbo Zhang, and Guojian Tang
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- 2023
14. Tightly Coupled GNSS/INS Integration with Robust Sequential Kalman Filter for Accurate Vehicular Navigation.
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Yi Dong, Dingjie Wang, Liang Zhang 0029, Qingsong Li, and Jie Wu
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- 2020
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15. Estimation of control Energy and control Strategies for Complex Networks.
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Dingjie Wang, Suoqin Jin, Fang-Xiang Wu, and Xiufen Zou
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- 2015
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16. The cogprime architecture for embodied Artificial General Intelligence.
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Ben Goertzel, Shujing Ke, Ruiting Lian, Jade O'Neill, Keyvan Sadeghi, Dingjie Wang, Oliver Watkins, and Gino Yu
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- 2013
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17. Pattern Mining for General Intelligence: The FISHGRAM Algorithm for Frequent and Interesting Subhypergraph Mining.
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Jade O'Neill, Ben Goertzel, Shujing Ke, Ruiting Lian, Keyvan Sadeghi, Simon C. K. Shiu, Dingjie Wang, and Gino Yu
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- 2012
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18. Syntax-Semantic Mapping for General Intelligence: Language Comprehension as Hypergraph Homomorphism, Language Generation as Constraint Satisfaction.
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Ruiting Lian, Ben Goertzel, Shujing Ke, Jade O'Neill, Keyvan Sadeghi, Simon C. K. Shiu, Dingjie Wang, Oliver Watkins, and Gino Yu
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- 2012
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19. Planning of refracted starlight observation based on observability analysis
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Dingjie Wang, Chengzhen Wu, Hongbo Zhang, and An Xueying
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symbols.namesake ,Optics ,business.industry ,Computer science ,Order (business) ,Mechanical Engineering ,symbols ,Aerospace Engineering ,Observability ,business ,Fisher information ,Refraction ,Starlight - Abstract
In traditional observation schemes of stellar refraction navigation, the accuracy was limited due to unreasonable observation directions. In order to ameliorate this situation, a method of refracted starlight observation based on observability analysis is proposed. The function of this method is optimally generating an observation attitude sequence according to standard trajectories of spacecraft so that the selection of a refracted starlight observation sequence can be realized. Specifically, the improvement of Fisher information matrix calculation enables this method to be qualified for the navigation problem with unsteady measurement quantities as well as the non-fully observability which is defined as the capability of estimating the system state through measurements in finite time. Here, we construct a quantitative relationship between refracted starlight measurements and system observability by means of Fisher information index ( FII). Next, the observation scheme is retrieved by searching the maximum value of the optimized variable, which includes the ( FII). Finally, we resort to the extended Kalman filter to accomplish typical trajectory navigation simulations of the observation scheme. The results indicate that our method brings more accuracy than traditional ones in estimation of position and velocity of the optimal observation scheme.
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- 2021
20. A novel inert crystal delivery medium for serial femtosecond crystallography
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Chelsie E. Conrad, Shibom Basu, Daniel James, Dingjie Wang, Alexander Schaffer, Shatabdi Roy-Chowdhury, Nadia A. Zatsepin, Andrew Aquila, Jesse Coe, Cornelius Gati, Mark S. Hunter, Jason E. Koglin, Christopher Kupitz, Garrett Nelson, Ganesh Subramanian, Thomas A. White, Yun Zhao, James Zook, Sébastien Boutet, Vadim Cherezov, John C. H. Spence, Raimund Fromme, Uwe Weierstall, and Petra Fromme
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serial femtosecond crystallography ,viscous crystal delivery ,protein complexes ,membrane proteins ,femtosecond studies ,nanocrystals ,coherent X-ray diffractive imaging ,free-electron laser ,Crystallography ,QD901-999 - Abstract
Serial femtosecond crystallography (SFX) has opened a new era in crystallography by permitting nearly damage-free, room-temperature structure determination of challenging proteins such as membrane proteins. In SFX, femtosecond X-ray free-electron laser pulses produce diffraction snapshots from nanocrystals and microcrystals delivered in a liquid jet, which leads to high protein consumption. A slow-moving stream of agarose has been developed as a new crystal delivery medium for SFX. It has low background scattering, is compatible with both soluble and membrane proteins, and can deliver the protein crystals at a wide range of temperatures down to 4°C. Using this crystal-laden agarose stream, the structure of a multi-subunit complex, phycocyanin, was solved to 2.5 Å resolution using 300 µg of microcrystals embedded into the agarose medium post-crystallization. The agarose delivery method reduces protein consumption by at least 100-fold and has the potential to be used for a diverse population of proteins, including membrane protein complexes.
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- 2015
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21. Lipidic cubic phase serial millisecond crystallography using synchrotron radiation
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Przemyslaw Nogly, Daniel James, Dingjie Wang, Thomas A. White, Nadia Zatsepin, Anastasya Shilova, Garrett Nelson, Haiguang Liu, Linda Johansson, Michael Heymann, Kathrin Jaeger, Markus Metz, Cecilia Wickstrand, Wenting Wu, Petra Båth, Peter Berntsen, Dominik Oberthuer, Valerie Panneels, Vadim Cherezov, Henry Chapman, Gebhard Schertler, Richard Neutze, John Spence, Isabel Moraes, Manfred Burghammer, Joerg Standfuss, and Uwe Weierstall
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lipidic cubic phases ,protein crystallography ,bacteriorhodopsin ,XFEL ,Crystallography ,QD901-999 - Abstract
Lipidic cubic phases (LCPs) have emerged as successful matrixes for the crystallization of membrane proteins. Moreover, the viscous LCP also provides a highly effective delivery medium for serial femtosecond crystallography (SFX) at X-ray free-electron lasers (XFELs). Here, the adaptation of this technology to perform serial millisecond crystallography (SMX) at more widely available synchrotron microfocus beamlines is described. Compared with conventional microcrystallography, LCP-SMX eliminates the need for difficult handling of individual crystals and allows for data collection at room temperature. The technology is demonstrated by solving a structure of the light-driven proton-pump bacteriorhodopsin (bR) at a resolution of 2.4 Å. The room-temperature structure of bR is very similar to previous cryogenic structures but shows small yet distinct differences in the retinal ligand and proton-transfer pathway.
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- 2015
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22. Fast non-line-of-sight imaging based on product-convolution expansions
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Weihao Xu, Songmao Chen, Yuyuan Tian, Dingjie Wang, and Xiuqin Su
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Diagnostic Imaging ,Fourier Analysis ,Atomic and Molecular Physics, and Optics ,Algorithms - Abstract
Non-line-of-sight (NLoS) imaging reveals a hidden scene using indirect diffuse reflections. A common choice for analyzing the time-of-flight (ToF) data from a non-confocal system is an ellipsoid model whose operator is high-dimensional, leading to a computationally arduous task. In this Letter, the product-convolution expansions method is utilized to formulate the operator and its adjoint based on the observation of a shift-variant point spread function (PSF) in the ToF data. The operator and its adjoint are locally approximated as a convolution, which allows the forward and backward procedure to be computed efficiently through fast Fourier transform (FFT). Moreover, the low-rank approximation of the operator is obtained by matrix decompositions, further improving the computational efficiency. The proposed method is validated using publicly accessible datasets.
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- 2022
23. A network-based computational framework to predict and differentiate functions for gene isoforms using exon-level expression data
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Dingjie Wang, Kin Fai Au, and Xiufen Zou
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Gene isoform ,Jaccard index ,Computer science ,Computational biology ,Article ,General Biochemistry, Genetics and Molecular Biology ,03 medical and health sciences ,Exon ,Humans ,Protein Isoforms ,splice ,Molecular Biology ,Gene ,030304 developmental biology ,0303 health sciences ,Sequence Analysis, RNA ,030302 biochemistry & molecular biology ,Alternative splicing ,Computational Biology ,High-Throughput Nucleotide Sequencing ,Exons ,Expression (mathematics) ,Alternative Splicing ,Gene Expression Regulation ,Neural Networks, Computer ,Software ,Network analysis - Abstract
Motivation Alternative splicing makes significant contributions to functional diversity of transcripts and proteins. Many alternatively spliced gene isoforms have been shown to perform specific biological functions under different contexts. In addition to gene-level expression, the advances of high-throughput sequencing offer a chance to estimate isoform-specific exon expression with a high resolution, which is informative for studying splice variants with network analysis. Results In this study, we propose a novel network-based analysis framework to predict isoform-specific functions from exon-level RNA-Seq data. In particular, based on exon-level expression data, we firstly propose a unified framework, referred to as Iso-Net, to integrate two new mathematical methods (named MINet and RVNet) that infer co-expression networks at different data scenarios. We demonstrate the superior prediction accuracy of Iso-Net over the existing methods for most simulation data, especially in two extreme cases: sample size is very small and exon numbers of two isoforms are quite different. Furthermore, by defining relevant quantitative measures (e.g., Jaccard correlation coefficient) and combining differential co-expression network analysis and GO functional enrichment analysis, a co-expression network analysis framework is developed to predict functions of isoforms and further, to discover their distinct functions within the same gene. We apply Iso-Net to study gene isoforms for several important transcription factors in human myeloid differentiation with the exon-level RNA-Seq data from three different cell lines. Availability and implementation Iso-Net is open source and freely available from https://github.com/Dingjie-Wang/Iso-Net .
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- 2021
24. Expression, purification and crystallization of CTB-MPR, a candidate mucosal vaccine component against HIV-1
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Ho-Hsien Lee, Irene Cherni, HongQi Yu, Raimund Fromme, Jeffrey D. Doran, Ingo Grotjohann, Michele Mittman, Shibom Basu, Arpan Deb, Katerina Dörner, Andrew Aquila, Anton Barty, Sébastien Boutet, Henry N. Chapman, R. Bruce Doak, Mark S. Hunter, Daniel James, Richard A. Kirian, Christopher Kupitz, Robert M. Lawrence, Haiguang Liu, Karol Nass, Ilme Schlichting, Kevin E. Schmidt, M. Marvin Seibert, Robert L. Shoeman, John C. H. Spence, Francesco Stellato, Uwe Weierstall, Garth J. Williams, Chunhong Yoon, Dingjie Wang, Nadia A. Zatsepin, Brenda G. Hogue, Nobuyuki Matoba, Petra Fromme, and Tsafrir S. Mor
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X-ray crystallography ,femtosecond nanocrystallography ,HIV-1 ,gp41 ,membrane-proximal region ,cholera toxin B subunit ,crystallization ,free-electron lasers ,Crystallography ,QD901-999 - Abstract
CTB-MPR is a fusion protein between the B subunit of cholera toxin (CTB) and the membrane-proximal region of gp41 (MPR), the transmembrane envelope protein of Human immunodeficiency virus 1 (HIV-1), and has previously been shown to induce the production of anti-HIV-1 antibodies with antiviral functions. To further improve the design of this candidate vaccine, X-ray crystallography experiments were performed to obtain structural information about this fusion protein. Several variants of CTB-MPR were designed, constructed and recombinantly expressed in Escherichia coli. The first variant contained a flexible GPGP linker between CTB and MPR, and yielded crystals that diffracted to a resolution of 2.3 Å, but only the CTB region was detected in the electron-density map. A second variant, in which the CTB was directly attached to MPR, was shown to destabilize pentamer formation. A third construct containing a polyalanine linker between CTB and MPR proved to stabilize the pentameric form of the protein during purification. The purification procedure was shown to produce a homogeneously pure and monodisperse sample for crystallization. Initial crystallization experiments led to pseudo-crystals which were ordered in only two dimensions and were disordered in the third dimension. Nanocrystals obtained using the same precipitant showed promising X-ray diffraction to 5 Å resolution in femtosecond nanocrystallography experiments at the Linac Coherent Light Source at the SLAC National Accelerator Laboratory. The results demonstrate the utility of femtosecond X-ray crystallography to enable structural analysis based on nano/microcrystals of a protein for which no macroscopic crystals ordered in three dimensions have been observed before.
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- 2014
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25. An optimal calibration method for gyro and star sensor based on observability analysis
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Yi Zhao, Dingjie Wang, Hongbo Zhang, and Guojian Tang
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Mechanical Engineering ,Aerospace Engineering - Abstract
The major challenge of current strapdown inertial navigation system/celestial navigation system (SINS/RCNS) is failing to calibrate all the error coefficients of gyro and star sensor in-flight accurately, which will lead to the attitude accuracy degradation. To address this question, this paper proposes an optimal calibration method based on observability analysis. Here, we derive the star sensor measurement model with respect to initial alignment errors, gyro errors, and star sensor installation errors. And the observability analysis is employed to explain the reason why all the error coefficients can be estimated effectively by three maneuvers merely. Finally, the optimal observation sequence is determined based on the fisher information matrix (FIM). The proposed optimal calibration method is evaluated by a representative suborbital flight vehicle trajectory, which represents significant improvements in estimation accuracy of error coefficients, and realizes the attitude accuracy enhancements.
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- 2023
26. Asynchronous RTK precise DGNSS positioning method for deriving a low-latency high-rate output
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Liang, Zhang, Hanfeng, Lv, Dingjie, Wang, Yanqing, Hou, and Jie, Wu
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- 2015
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27. Constrained MEMS-Based GNSS/INS Tightly Coupled System With Robust Kalman Filter for Accurate Land Vehicular Navigation
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Qingsong Li, Dingjie Wang, Zhaoyang Li, Yi Dong, and Jie Wu
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Noise measurement ,Computer science ,020208 electrical & electronic engineering ,Real-time computing ,Satellite system ,02 engineering and technology ,Kalman filter ,GNSS applications ,Robustness (computer science) ,0202 electrical engineering, electronic engineering, information engineering ,Satellite ,Electrical and Electronic Engineering ,Instrumentation ,Inertial navigation system - Abstract
Special approaches are required to integrate low-cost MEMS-based inertial navigation system (MEMS-INS) with global navigation satellite system (GNSS). This article proposes a robust GNSS/MEMS-strapdown inertial navigation system (SINS), the tightly coupled navigation approach aided by non-holonomic constraint (NHC). The tight integration model is adopted to overcome the accuracy degradation caused by changing satellite geometry and frequent GNSS outages in urban areas. The innovation-based test statistic is devised to enhance the filtering with the resistance to GNSS outliers. To further improve the stand-alone accuracy during relatively long GNSS outages, the virtual measurement is also introduced using the NHC condition that land vehicle does not slip and always remain in contact with the ground. The field test results with continuous GNSS aiding indicate that the proposed algorithm can improve overall accuracy in position, velocity, and attitude by about 16, 43, and 19% with immunity from GNSS outliers, compared with the traditional loosely coupled (LC) method. Even during 60-s GNSS outages, the proposed algorithm can effectively compensate MEMS-SINS errors, accomplishing the overall accuracy improvements by about 46% (position), 35% (velocity), and 15% (attitude), compared with the traditional LC counterpart.
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- 2020
28. Tensor-based mathematical framework and new centralities for temporal multilayer networks
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Xiufen Zou, Wei Yu, and Dingjie Wang
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Multilinear algebra ,Information Systems and Management ,Theoretical computer science ,Spacetime ,Computer science ,05 social sciences ,Complex system ,050301 education ,02 engineering and technology ,Computer Science Applications ,Theoretical Computer Science ,Artificial Intelligence ,Control and Systems Engineering ,Iterative refinement ,0202 electrical engineering, electronic engineering, information engineering ,Entropy (information theory) ,020201 artificial intelligence & image processing ,Matrix analysis ,0503 education ,Software - Abstract
Although networks provide a powerful methodology to study a variety of real-world and engineered systems, their current formulation does not typically account for multiple interaction types that vary in space and time, or address interconnected systems such as networks of networks. Unavoidably, ignoring time-dependence and multiple interactions of topological structures might lead to important temporal and structural information loss and may obscure the actual organization. To achieve a deep understanding of the time-varying and interconnected complex networked systems, in this paper, we develop a more general mathematical model, referred to as a temporal multilayer network, which explicitly incorporates time-dependence and multiple relationships of topological structures into a system, and provides a natural and reasonable description for real-world complex systems. Furthermore, using a fifth-order tensorial framework to represent temporal multilayer networks, we generalize four important topological metrics, including overlapping degree, entropy, degree correlation and link overlap, to quantitatively evaluate the temporal multilayer networks. In particular, based on the tensorial framework, we propose two iterative refinement centralities for temporal multilayer networks, referred to as TM-eigenvector and TM-PageRank centralities, which are used to quantitatively evaluate the importance of nodes in real-world complex systems. Moreover, we use the theory of multilinear algebra and matrix analysis to strictly prove the convergence of these iterative algorithms. The proposed mathematical frameworks are validated using two real-world temporal multilayer networked systems related to complex diseases, i.e., influenza and heart diseases.
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- 2020
29. Using Multi-Antenna Trajectory Constraint to Analyze BeiDou Carrier-Phase Observation Error of Dynamic Receivers
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Qingsong Li, Chenyao Xiong, Dingjie Wang, and Jie Wu
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Observational error ,GNSS ,Computer science ,integrity monitoring ,Chemical technology ,Failure rate ,TP1-1185 ,Mixture model ,Biochemistry ,Atomic and Molecular Physics, and Optics ,Standard deviation ,Article ,Analytical Chemistry ,dynamic receiver ,Position (vector) ,Control theory ,GNSS applications ,Trajectory ,error bounding ,Electrical and Electronic Engineering ,Antenna (radio) ,Instrumentation ,characteristic analysis - Abstract
Appropriate cycle-slip and measurement-error models are essential for BeiDou carrier-phase-based integrity risk calculation. To establish the receiver’s measurement-error model, an accurate position reference of the GNSS antenna is fundamental for calculating the measurement error. However, it is still a challenge to acquire position references for dynamic BeiDou receivers, resulting in improper GNSS measurement-error models and unreliable integrity monitoring. This paper proposes an improved precise relative positioning scheme by adopting multi-antenna trajectory constraints for dynamic BeiDou receivers. The dynamic experiments show an obvious decline of 78.7%, at most, in the positioning failure rate of the proposed method, as compared with the traditional method. The position solutions obtained from the proposed approach are used as the reference to analyze the cycle-slip and measurement-error characteristics of the dynamic receiver. The field test results indicate that the cycle-slip rate decreases with the increase of signal-to-noise ratio (SNR), and cycle slipping obeys a positively skewed distribution that could be fitted by the Gaussian mixture model (GMM). On the other hand, the standard deviation of the carrier-phase measurement error is inversely proportional to SNR, and its distribution is characteristically fat-tailed, which could be fitted by the bi-normal model.
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- 2021
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30. Systematic assessment of long-read RNA-seq methods for transcript identification and quantification
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Hazuki Takahashi, Christopher Vollmers, Stefan Goetz, Margaret E. Hunter, Gabriela Balderrama-Gutierrez, David Moraga, Maite De María, Mark Diekhans, Francisco Jose Pardo-Palacios, Piero Carninci, Jonathan M. Mudge, Roderic Guigó, Gloria M. Sheynkman, Ingrid Youngworth, Kin Fai Au, Matthew Adams, Muhammed Hasan Çelik, Haoran Li, Alison D. Tang, Ana Conesa, Silvia Carbonell-Sala, Barbara J. Wold, Angela N. Brooks, Brian Williams, Julien Lagarde, Cindy Liang, Fairlie Reese, Ali Mortazavi, Andrey D. Prjibelski, Natàlia Garcia-Reyero, Jane E. Loveland, Nancy D. Denslow, Dingjie Wang, Amit Behera, Adam Frankish, Hagen Tilgner, and Carlos Menor
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Identification (biology) ,RNA-Seq ,Computational biology ,Biology - Abstract
With increased usage of long-read sequencing technologies to perform transcriptome analyses, there becomes a greater need to evaluate different methodologies including library preparation, sequencing platform, and computational analysis tools. Here, we report the study design of a community effort called the Long-read RNA-Seq Genome Annotation Assessment Project (LRGASP) Consortium, whose goals are characterizing the strengths and remaining challenges in using long-read approaches to identify and quantify the transcriptomes of both model and non-model organisms. The LRGASP organizers have generated cDNA and direct RNA datasets in human, mouse, and manatee samples using different protocols followed by sequencing on Illumina, Pacific Biosciences, and Oxford Nanopore Technologies platforms. Participants will use the provided data to submit predictions for three challenges: transcript isoform detection with a high-quality genome, transcript isoform quantification, and de novo transcript isoform identification. Evaluators from different institutions will determine which pipelines have the highest accuracy for a variety of metrics using benchmarks that include spike-in synthetic transcripts, simulated data, and a set of undisclosed, manually curated transcripts by GENCODE. We also describe plans for experimental validation of predictions that are platform-specific and computational tool-specific. We believe that a community effort to evaluate long-read RNA-seq methods will help move the field toward a better consensus on the best approaches to use for transcriptome analyses.
- Published
- 2021
31. A high-accuracy constrained SINS/CNS tight integrated navigation for high-orbit automated transfer vehicles
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Jie Wu, Dingjie Wang, Xueying An, and Hanfeng Lv
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0209 industrial biotechnology ,Celestial navigation ,Computer science ,Real-time computing ,Aerospace Engineering ,02 engineering and technology ,Accelerometer ,High Earth orbit ,01 natural sciences ,010305 fluids & plasmas ,Computer Science::Robotics ,Noise ,020901 industrial engineering & automation ,0103 physical sciences ,Trajectory ,Orbit (dynamics) ,Inertial navigation system ,Information filtering system - Abstract
High-accuracy and reliable autonomous navigation is increasingly crucial for automated transfer vehicles (ATV). This paper proposes a novel strapdown inertial navigation system/celestial navigation system (SINS/CNS) tight integration scheme aided by dynamic model constraints for high-orbit ATV to realize accurate and autonomous navigation. In this scheme, the complete weightlessness constraint in orbit is used to address the divergence of position and velocity caused by inaccurate accelerometer bias estimation problem encountered in the traditional SINS/CNS integration method, and the image point position-based tight integration model is derived to handle the adverse influence of time-varying attitude measurement noise due to changes of star geometry observed by a large-view-filed star sensor. Moreover, an information filter is devised to fuse the multi-rate measurements. The proposed algorithm is evaluated by a representative high-orbit ATV trajectory simulation, which indicates significant improvements in navigation accuracy compared with its traditional counterparts. The proposed algorithm can realize navigation accuracy enhancements without introducing additional sensors, strengthening its potentials in engineering application.
- Published
- 2018
32. A real-time inertial-aided cycle slip detection method based on ARIMA-GARCH model for inaccurate lever arm conditions
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Qingsong Li, Yi Dong, Jie Wu, Dingjie Wang, and Liang Zhang
- Subjects
Heteroscedasticity ,Volatility clustering ,010504 meteorology & atmospheric sciences ,Computer science ,Autoregressive conditional heteroskedasticity ,Pseudorange ,010502 geochemistry & geophysics ,01 natural sciences ,Constant false alarm rate ,Autoregressive model ,General Earth and Planetary Sciences ,Autoregressive integrated moving average ,Conditional variance ,Algorithm ,0105 earth and related environmental sciences - Abstract
The processing of cycle slip is one of the key techniques of carrier-phase-based high-precision positioning. As for the poor performance of the single-station inertial-aided cycle slip detection based on the tightly coupled integration system using pseudorange and Doppler measurements under inaccurate lever arm conditions, an improved real-time method based on ARIMA-GARCH (autoregressive integrated moving average-generalized autoregressive conditional heteroscedastic) model is proposed. The ARIMA (1, 1, 0) model is used to detrend the fundamental test statistics, and then, the GARCH (1,1) model is used to estimate the conditional variance of the residuals with the characteristics of volatility clustering. Considering the needs for real-time applications, two algorithms with model parameters varied at every epoch and periodically, respectively, are proposed. Two kinds of numerical experiments based on the real data collected from vehicular and flight tests are carried out. The results show that the proposed method can not only greatly reduce the false alarm rate but also can detect simulated 1-cycle slips for all frequencies of all satellites of BDS (BeiDou System) and the period-varied algorithm is recommended due to its good performance of cycle slip detection and low computation cost online.
- Published
- 2021
33. Research on Error Online Calibration Method of Inertial/Stellar Refraction Integrated Navigation System
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Jie Wu, Dingjie Wang, Qiaochu Lv, and Xueying An
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Inertial frame of reference ,Computer science ,Linearization ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Calibration ,Navigation system ,Astrophysics::Earth and Planetary Astrophysics ,Observability ,Refraction ,Inertial navigation system ,Simulation ,Starlight - Abstract
Inertial/stellar refraction integrated navigation system can use the observation information of the refraction star sensor to correct the output of the inertial navigation system (INS), thereby effectively improving the positioning performance of the integrated navigation system. However, in practical applications, the errors of navigation system such as inertial navigation misalignment angle and star sensor installation error will affect the overall performance of the integrated navigation system to some extent, so it needs to be calibrated online. Since the carrier cannot achieve continuous observation of the refracted starlight, the system observability is weak. Therefore, a new online error calibration strategy is proposed, which is to construct observations by using the position information of the INS and the attitude and star spots information of the star sensor, and establish the relationship equations between the observations, the misalignment angle of the inertial navigation and installation error of star sensor. After linearization and decoupling, the inertial navigation misalignment angle and star sensor installation error are estimated by the least square method. Monte Carlo target practice simulation results show that, compared with the traditional filtering estimation method, the system error online calibration method proposed in this paper can more effectively estimate the inertial navigation misalignment angle and star sensor installation error, and improve the positioning and speed accuracy of the inertial/stellar refraction integrated navigation system.
- Published
- 2021
34. Low-latency, high-rate, high-precision relative positioning with moving base in real time
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Dingjie Wang, Jie Wu, Qingsong Li, Liang Zhang, Mingkui Wu, and Yi Dong
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High rate ,010504 meteorology & atmospheric sciences ,Network packet ,Computer science ,Real-time computing ,Satellite system ,Kinematics ,010502 geochemistry & geophysics ,01 natural sciences ,Asynchronous communication ,General Earth and Planetary Sciences ,Latency (engineering) ,Inertial navigation system ,0105 earth and related environmental sciences ,Fixed base - Abstract
Relative positioning with a moving base is required in many vehicle-to-vehicle applications. Due to unavoidable latency, conventional synchronous real-time kinematic (SRTK) positioning, which refers a fixed base, cannot fulfill the requirements of high-speed safety–critical situations since the movement of the base during the latency must be considered. We present an asynchronous RTK (ARTK)/time-differenced carrier phase (TDCP) integration method. We first introduce the ARTK method to directly obtain the asynchronous baseline between moving base and rover at their respective observation epochs. The position increments of the moving base during the latency are then calculated by the TDCP technique. Finally, the two positioning results are combined to achieve low-latency, high-rate, and high-precision relative positioning. With the proposed method, the size of transmitted data packets can be significantly reduced, which is beneficial for real-time implementation. It is also noted that the proposed method can be easily merged with global navigation satellite system/inertial navigation system (INS) integration to further improve the output rate of relative position. The performance is evaluated by a field test using two moving vehicles with one being the moving base and the other the rover. Results show that the baseline error is less than 1 cm compared to reliably post-processed SRTK results when latencies of raw observations remain below 1 s. Even when the latency is 15 s, centimeter-level accuracy can still be guaranteed. With ARTK/TDCP/INS integration, decimeter-to-centimeter-level higher-rate (> 100 Hz) relative positioning results can be obtained.
- Published
- 2020
35. Error Modeling and Integrity Risk Analysis in SPP
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Qingsong Li, Yuan Song, Jie Wu, Wanli Jian, Yi Dong, and Dingjie Wang
- Subjects
Risk analysis ,GNSS applications ,Computer science ,Position (vector) ,Estimation theory ,Robustness (computer science) ,Civil aviation ,Fault (power engineering) ,Residual ,Algorithm - Abstract
With the popularity and development of GNSS, the concept of integrity is proposed in order to ensure the safety of navigation and positioning. In some related fields such as civil aviation and lifesaving, the requirements for the integrity are becoming stricter, making the Integrity Monitoring a hot issue to be solved urgently. However, the existing methods for this problem are theoretically imperfect and the error model used can’t accurately describe the actual error distribution. In this article, we will first present a model for the observation error in single point positioning. Considering that the actual observation errors always have thick tails, a binormal error model has been raised. Next, based on the previous error model, we use the Robust Parameter Estimation (RPE) method based on predicted residual with single iteration to detect and exclude the fault observation values, and then calculate the positioning result. Finally, we derive a method for conservatively estimating the integrity risk in the position by segmenting and magnifying the test-passing domain. The experimental results show that compared with the single normal error model, our binormal error model can describe the actual error distribution better and is conservative in the tail. The RPE method based on predicted residual with single iteration has a good effect of detecting and excluding fault observations and has a small positioning error. When the theoretical risk is less than the risk threshold, the statistical integrity risk obtained from the data is also less than the threshold. In addition, in the case of a worse error distribution with larger fault probability and larger fault error variance, the integrity risk evaluation results are still credible, indicating our method has better robustness.
- Published
- 2020
36. An enhanced tightly-coupled integrated navigation approach using phase-derived position increment (PDPI) measurement
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Zhaoyang Li, Jie Wu, Yi Dong, and Dingjie Wang
- Subjects
010504 meteorology & atmospheric sciences ,010401 analytical chemistry ,Pseudorange ,Phase (waves) ,Navigation system ,Recursion (computer science) ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,symbols.namesake ,Position (vector) ,Horizontal position representation ,symbols ,Electrical and Electronic Engineering ,Doppler effect ,Algorithm ,Smoothing ,0105 earth and related environmental sciences ,Mathematics - Abstract
In this paper, an enhanced tightly coupled navigation approach using pseudorange, Doppler and carrier phase measurements is proposed. Firstly, the PDPI vector is obtained by differencing time-differenced carrier phase measurements between satellites. Then, the difference between PDPI and position increment derived from SINS recursion is determined. Finally, navigation system states are adjusted by the precise difference of position increment. Compared with time-differenced carrier phase measurements, the introduction of precise PDPI measurements, derived from time-differenced carrier phase, can increase computation efficiency without iteration calculations. A field vehicular test is performed to verify the proposed approach. In comparison with the method using pseudorange and Doppler measurements, the PDPI-aided method improves performance of navigation system significantly. On one hand, since high-precise PDPI measurement is added in the new approach, accuracy of the integrated navigation system is improved. The results show horizontal position error is reduced by 56.9% and horizontal velocity error is reduced by 39.2%. Vertical velocity error is reduced by 81.0% and the heading error is reduced by 19.3%. On the other hand, the PDPI measurement in this new approach establishes the relationship between two successive epochs, which leads to a smoothing effect.
- Published
- 2018
37. A new centrality measure of nodes in multilayer networks under the framework of tensor computation
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Dingjie Wang and Xiufen Zou
- Subjects
0301 basic medicine ,Mathematical optimization ,Multilinear algebra ,Theoretical computer science ,Iterative method ,Applied Mathematics ,Computation ,Network theory ,01 natural sciences ,Measure (mathematics) ,Field (computer science) ,010305 fluids & plasmas ,03 medical and health sciences ,030104 developmental biology ,Modeling and Simulation ,Tensor (intrinsic definition) ,0103 physical sciences ,Centrality ,Mathematics - Abstract
One challenging issue in information science, biological systems and many other field is to determine the most central agents in multilayer networked systems characterized by different types of interrelationships. In this paper, using a fourth-order tensor to represent multilayer networks, we propose a new centrality measure, referred to as the Singular Vector of Tensor (SVT) centrality, which is used to quantitatively evaluate the importance of nodes connected by different types of links in multilayer networks. First, we present a novel iterative method to obtain four alternative metrics that can quantify the hub and authority scores of nodes and layers in multilayer networked systems. Moreover, we use the theory of multilinear algebra to prove that the four metrics converge to four singular vectors of the adjacency tensor of the multilayer network under reasonable conditions. Furthermore, a novel SVT centrality measure is obtained by integrating these four metrics. The experimental results demonstrate that the proposed method is a new centrality measure that significantly outperforms six other published centrality methods on two real-world multilayer networks related to complex diseases, i.e., gastric and colon cancers.
- Published
- 2018
38. Trajectory Control in Nonlinear Networked Systems and Its Applications to Complex Biological Systems
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Xiufen Zou, Suoqin Jin, and Dingjie Wang
- Subjects
0301 basic medicine ,03 medical and health sciences ,Nonlinear system ,030104 developmental biology ,Computer science ,Applied Mathematics ,0103 physical sciences ,Control (management) ,Network science ,Control engineering ,01 natural sciences ,Trajectory control ,010305 fluids & plasmas - Abstract
The control of nonlinear networked systems is one of the challenging problems in the network science and engineering fields. Based on physical and realistic considerations, it is a critical goal to...
- Published
- 2018
39. A novel constrained ambiguity resolution approach for Beidou attitude determination
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Liang Zhang, Jie Wu, Dingjie Wang, Yi Dong, and Qingsong Li
- Subjects
Atmospheric Science ,Ambiguity resolution ,010504 meteorology & atmospheric sciences ,Computer science ,media_common.quotation_subject ,Reliability (computer networking) ,Aerospace Engineering ,Astronomy and Astrophysics ,Ambiguity ,Tracing ,010502 geochemistry & geophysics ,01 natural sciences ,Nonlinear system ,Matrix (mathematics) ,Geophysics ,Space and Planetary Science ,Linearization ,General Earth and Planetary Sciences ,Orthonormal basis ,Algorithm ,0105 earth and related environmental sciences ,media_common - Abstract
This paper develops a novel approach to obtain the fixed ambiguity solution with orthonormal constraints for Beidou attitude determination. The approach extends the traditional attitude model by taking the attitude matrix elements as unknown parameters directly. The orthonormal property of the attitude matrix is used as constraints to assist in calculating the float ambiguity solution and its corresponding variance–covariance matrix. An iteration algorithm with the linearization of orthonormal constraints is developed to solve the nonlinear conditional extremum problem and a sequential filtering multi-epoch ambiguity resolution method is derived for real-time applications. Long-time static experiments with three antennas tracing Beidou signals are employed to demonstrate the reliability and effectiveness of the proposed approach. The results indicate that, compared to unconstrained ambiguity resolution, the proposed approach can improve the reliability of the integer ambiguity vectors for single epochs and can also decrease the time to fix for multiple epochs.
- Published
- 2017
40. A novel SINS/CNS Integrated Navigation Method Using Model Constraints for Ballistic Vehicle Applications
- Author
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Hanfeng Lv, Jie Wu, and Dingjie Wang
- Subjects
Nonholonomic system ,0209 industrial biotechnology ,Inertial frame of reference ,Celestial navigation ,Ballistic missile ,Land navigation ,Ocean Engineering ,02 engineering and technology ,Oceanography ,Accelerometer ,01 natural sciences ,010305 fluids & plasmas ,Computer Science::Robotics ,020901 industrial engineering & automation ,Geography ,0103 physical sciences ,Free flight ,Simulation ,Information filtering system - Abstract
The major challenge of current Strapdown Inertial Naviagtion System/Celestial Navigation System (SINS/CNS) integrated systems is navigation accuracy degradation due to the failure to accurately estimate the accelerometer bias even when using stellar refraction information (e.g. the number of refraction stars is less than three). To solve this problem, this paper presents a new method for improving the accuracy of the traditional inertial-based integrated systems installed on ballistic vehicles. In an analogy with nonholonomic constraints in land navigation, this algorithm exploits the constraints that govern the motion of a ballistic vehicle in the free flight phase to obtain accelerometer bias observations. Improvements in dynamic equations are used to reduce the propagation of navigation errors, and high-rate virtual constraints are used to reduce the impact of bias errors. An information filter is devised to fuse the multi-rate observations from multiple sources, i.e. SINS, CNS and model constraints. The proposed method is also evaluated by long-range ballistic vehicle navigation simulations. The results indicate that the proposed constrained algorithm can address the degradation problem with remarkable accuracy improvements without adding extra sensors, enhancing the SINS-based navigation performance for ballistic applications.
- Published
- 2017
41. Augmented Cubature Kalman filter for nonlinear RTK/MIMU integrated navigation with non-additive noise
- Author
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Hanfeng Lv, Jie Wu, and Dingjie Wang
- Subjects
0209 industrial biotechnology ,Engineering ,business.industry ,Applied Mathematics ,020208 electrical & electronic engineering ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Control engineering ,02 engineering and technology ,Filter (signal processing) ,Kalman filter ,Condensed Matter Physics ,Sensor fusion ,Flight test ,Extended Kalman filter ,Noise ,020901 industrial engineering & automation ,GNSS applications ,Control theory ,0202 electrical engineering, electronic engineering, information engineering ,Electrical and Electronic Engineering ,business ,Instrumentation ,Inertial navigation system - Abstract
In order to enhance the capability of autonomous operation for small unmanned aerial vehicles (UAV), a MEMS-based inertial navigation system (INS)/global navigation satellite system (GNSS) integrated navigation method is proposed. An augmented Cubature Kalman filter is derived to fulfil the data fusion of precise GNSS real-time kinematic (RTK) solution and noisy inertial measurements. In the filter, Cubature Kalman filtering is adopted to handle the strong INS model nonlinearity caused by sudden and large UAV maneuvers, and the technique of state-augmentation is used to capture meaningful odd-order moment information and reduce the adverse impacts of non-additive noise in inertial measurements. It is analyzed that the basic difference between the augmented and non-augmented CKFs generally favors the augmented CKF, which is supported by a representative example and flight test. The results of flight test have also shown that the proposed augmented Cubature Kalman filtering method can complete more accurate navigation compared with the conventional EKF/UKF-based approaches.
- Published
- 2017
42. Additional file 1: of Control of multilayer biological networks and applied to target identification of complex diseases
- Author
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Zheng, Wei, Dingjie Wang, and Xiufen Zou
- Abstract
Figure S1. In Pathways in cancer, the above genes are clustered near the PI3K-AKT signaling pathway. Figure S2. In Colorectal cancer pathway, the above genes are clustered near the PI3K-AKT signaling pathway and MAPK signaling pathway. Figure S3. In Apoptosis pathway, the above genes are clustered near the PI3K-AKT signaling pathway and NF-κB signaling pathway. Figure S4. In B cell receptor signaling pathway, the above genes are clustered near the PI3K-AKT signaling pathway, MAPK signaling pathway and NF-κB signaling pathway. Figure S5. In T cell receptor signaling pathway, the above genes are clustered near the MAPK signaling pathway and NF-κB signaling pathway. Figure S6. The enrichment analysis of genes from MsigDB database. Table S1. Biological functions of nodes in MFVS for three multilayer networks. Table S2. The names of drugs that AKT, P21, BCATENIN, IFNG, JAK, JUN, NFKB, IKB, PI3K, RAF, SMAD, P53 and IAP can combine with. Table S3. The drugs which ENV, GAG, NEF and GAG-POL can combine with. Table S4. Enrichment analysis of genes in MFVS of the HHMG network. Table S5. The biological information of cytokines and cell types related to cancer immune system. (PDF 626 kb)
- Published
- 2019
- Full Text
- View/download PDF
43. A Modified TDCP/INS Tightly Coupled Navigation
- Author
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Yi Dong, Dingjie Wang, Jie Wu, and Wanli Jian
- Subjects
Carrier phase ,Epoch (reference date) ,Computer science ,GNSS applications ,Position (vector) ,Computation ,Real-time computing ,Pseudorange ,Kalman filter ,Inertial navigation system - Abstract
Nowadays, the navigation systems, such as phone-based and vehicle navigation, are developing, and techniques of GNSS/INS loosely and tightly coupled navigation are under widely used. Compared with loosely coupled navigation, the tightly coupled navigation shows more and more superiorities in urban canyons, because it can provide continuous integrated navigation solution even with less than four satellites. Conventional tightly coupled navigation only use pseudo range and Doppler observations, while the time-differenced carrier phase (TDCP)/Inertial navigation system (INS) tightly coupled navigation uses an extra TDCP observation; this can provides higher attitude accuracy than the conventional tightly coupled navigation. However, the mathematical model of the conventional TDCP/INS tightly coupled navigation makes difference between the reference epoch and current epoch, this creates poor real-time. To improve the accuracy and reduce the computation burden, this paper presents a modified TDCP/INS tightly coupled navigation method, infers a modified mathematical model of TDCP, which can make difference between the current 0.1 s epoch. The experimental results show that, compared with the loosely coupled navigation, the modified TDCP/INS tightly coupled navigation method provides higher accuracy of position, velocity and attitude. As expected, compared with the conventional tightly coupled navigation, the attitude accuracy is significantly improved, meanwhile the accuracy of position and velocity are slightly improved. In the face of few observable satellites and turning, the modified TDCP/INS tightly coupled navigation method shows a clear advantage.
- Published
- 2019
44. Novel In-flight Coarse Alignment of Low-cost Strapdown Inertial Navigation System for Unmanned Aerial Vehicle Applications
- Author
-
Dingjie Wang, Jie Wu, and Liang Chen
- Subjects
020301 aerospace & aeronautics ,Computer science ,business.industry ,020208 electrical & electronic engineering ,Aerospace Engineering ,02 engineering and technology ,0203 mechanical engineering ,Space and Planetary Science ,0202 electrical engineering, electronic engineering, information engineering ,Aerospace engineering ,Air navigation ,business ,Inertial navigation system ,Remote sensing - Published
- 2016
45. Using Allan variance to improve stochastic modeling for accurate GNSS/INS integrated navigation
- Author
-
Zhaoyang Li, Jie Wu, Dingjie Wang, Yi Dong, and Qingsong Li
- Subjects
Inertial frame of reference ,010504 meteorology & atmospheric sciences ,Computer science ,010401 analytical chemistry ,Real-time computing ,Satellite system ,Kalman filter ,01 natural sciences ,Signal ,0104 chemical sciences ,Position (vector) ,GNSS applications ,General Earth and Planetary Sciences ,Allan variance ,Inertial navigation system ,0105 earth and related environmental sciences - Abstract
MEMS-based integrated system of a global navigation satellite system (GNSS) and an inertial navigation system (INS) has been widely used in various navigation applications. However, such integration encounters some major limitations. On the one hand, the noisy MEMS-based INS undermines the accuracy with time during the frequently occurring GNSS outages caused by signal blockage or attenuation in certain situations such as urban canyon, tunnels, and high trees. On the other hand, the model mismatch between actual GNSS error and the assumed one would also degrade the obtained accuracy even with continuous GNSS aiding. To improve the overall performance for GNSS/MEMS-INS, better error models can be obtained using Allan variance (AV) analysis technique for modeling inertial sensor errors instead of the commonly recommended auto-regressive processes, and on the other hand, the measurement update in Kalman filter is improved using innovation filtering and AV calculation. The performance of each method and the combined algorithm is evaluated by a field test with either differential GNSS (DGNSS) or single-point positioning (SPP) as external aid. In addition to the considerable navigation enhancement brought by each method, the experimental results show the combined algorithm accomplishes overall accuracy improvements by about 18% (position), 8% (velocity), and 38% (attitude) for integration with DGNSS, and by about 15% (position), 75% (velocity), and 77% (attitude) for that with SPP, compared with corresponding traditional counterparts.
- Published
- 2018
46. Erratum: Corrigendum: Diffraction data of core-shell nanoparticles from an X-ray free electron laser
- Author
-
Christopher Kupitz, Chun Ya Chiu, Dingjie Wang, Richard A. Kirian, Brenda G. Hogue, Michael H. Huang, Lutz Foucar, Petra Fromme, Elisabeth Hartmann, Marc Messerschmidt, Sabine Botha, Shibom Basu, Xuanxuan Li, Anton Barty, Andreas Menzel, Stephan Kassemeyer, Hsiang Ju Wang, R. Bruce Doak, Daniel James, Uwe Weierstall, Henry N. Chapman, Ilme Schlichting, Haiguang Liu, Fenglin Wang, Robert M. Lawrence, Raimund Fromme, Robert L. Shoeman, Mengning Liang, John C. H. Spence, Aliakbar Jafarpour, Sébastien Boutet, Garrett Nelson, and Garth J. Williams
- Subjects
0301 basic medicine ,Diffraction ,Statistics and Probability ,Analytical chemistry ,Free-electron laser ,X-ray ,Anatomy ,Biology ,Core shell nanoparticles ,Library and Information Sciences ,Computer Science Applications ,Education ,03 medical and health sciences ,030104 developmental biology ,Statistics, Probability and Uncertainty ,Information Systems - Abstract
Scientific Data 4:170048 doi: 10.1038/sdata201748 (2017); Published 11 April 2017; Updated 24 October 2017. The Data Descriptor incorrectly states the number of normal incidences used to generate the plot in Fig. 4b as 209. This plot was generated from 32 normal incidence cases.
- Published
- 2017
- Full Text
- View/download PDF
47. A novel inert crystal delivery medium for serial femtosecond crystallography
- Author
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Vadim Cherezov, Nadia A. Zatsepin, Jason E. Koglin, Chelsie E. Conrad, Andrew Aquila, Christopher Kupitz, Shatabdi Roy-Chowdhury, Uwe Weierstall, Shibom Basu, Alexander Schaffer, Raimund Fromme, Yun Zhao, Petra Fromme, John C. H. Spence, Thomas A. White, Cornelius Gati, Jesse Coe, James Zook, Ganesh Subramanian, Daniel James, Dingjie Wang, Mark S. Hunter, Sébastien Boutet, and Garrett Nelson
- Subjects
serial femtosecond crystallography ,membrane proteins ,Biochemistry ,law.invention ,Crystal ,chemistry.chemical_compound ,nanocrystals ,free-electron laser ,law ,coherent X-ray diffractive imaging ,ddc:530 ,General Materials Science ,protein complexes ,Crystallography ,Chemistry ,Resolution (electron density) ,femtosecond studies ,General Chemistry ,equipment and supplies ,Condensed Matter Physics ,Laser ,Research Papers ,viscous crystal delivery ,Nanocrystal ,Membrane protein ,QD901-999 ,Femtosecond ,Agarose ,Protein crystallization - Abstract
Viscous sample delivery that decreases the net protein consumed in serial femtosecond crystallography is described. The agarose stream has a low background, is compatible with membrane proteins and can be used at a wide range of temperatures., Serial femtosecond crystallography (SFX) has opened a new era in crystallography by permitting nearly damage-free, room-temperature structure determination of challenging proteins such as membrane proteins. In SFX, femtosecond X-ray free-electron laser pulses produce diffraction snapshots from nanocrystals and microcrystals delivered in a liquid jet, which leads to high protein consumption. A slow-moving stream of agarose has been developed as a new crystal delivery medium for SFX. It has low background scattering, is compatible with both soluble and membrane proteins, and can deliver the protein crystals at a wide range of temperatures down to 4°C. Using this crystal-laden agarose stream, the structure of a multi-subunit complex, phycocyanin, was solved to 2.5 Å resolution using 300 µg of microcrystals embedded into the agarose medium post-crystallization. The agarose delivery method reduces protein consumption by at least 100-fold and has the potential to be used for a diverse population of proteins, including membrane protein complexes.
- Published
- 2015
48. Structure of the Angiotensin Receptor Revealed by Serial Femtosecond Crystallography
- Author
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Gye Won Han, Vadim Cherezov, Sadashiva S. Karnik, Marc Messerschmidt, Qingping Xu, Sébastien Boutet, Andrii Ishchenko, Cornelius Gati, Russell Desnoyer, Petra Fromme, Garrett Nelson, Vsevolod Katritch, Dingjie Wang, Haitao Zhang, Jesse Coe, Nadia A. Zatsepin, Thomas A. White, Chelsie E. Conrad, Kalyan C. Tirupula, Daniel James, Chong Wang, Wei Liu, Garth J. Williams, Michael R. Sawaya, Oleksandr Yefanov, Hamiyet Unal, Uwe Weierstall, and Raymond C. Stevens
- Subjects
Angiotensin receptor ,Biochemistry, Genetics and Molecular Biology(all) ,Regulator ,Biology ,Angiotensin II ,Article ,General Biochemistry, Genetics and Molecular Biology ,3. Good health ,Crystallography ,Docking (molecular) ,ddc:570 ,Femtosecond ,Receptor ,Peptide sequence ,G protein-coupled receptor - Abstract
Angiotensin II type 1 receptor (AT(1)R) is a G protein-coupled receptor that serves as a primary regulator for blood pressure maintenance. Although several anti-hypertensive drugs have been developed as AT(1)R blockers (ARBs), the structural basis for AT(1)R ligand-binding and regulation has remained elusive, mostly due to the difficulties of growing high-quality crystals for structure determination using synchrotron radiation. By applying the recently developed method of serial femtosecond crystallography at an X-ray free-electron laser, we successfully determined the room-temperature crystal structure of the human AT(1)R in complex with its selective antagonist ZD7155 at 2.9-angstrom resolution. The AT(1)R-ZD7155 complex structure revealed key structural features of AT(1)R and critical interactions for ZD7155 binding. Docking simulations of the clinically used ARBs into the AT(1)R structure further elucidated both the common and distinct binding modes for these antihypertensive drugs. Our results thereby provide fundamental insights into AT(1)R structure-function relationship and structure-based drug design.
- Published
- 2015
49. Lipidic cubic phase serial millisecond crystallography using synchrotron radiation
- Author
-
Markus Metz, Vadim Cherezov, Peter Berntsen, Dingjie Wang, Richard Neutze, Wenting Wu, Gebhard F. X. Schertler, Linda C. Johansson, Isabel Moraes, Dominik Oberthuer, Thomas A. White, Henry N. Chapman, Valerie Panneels, Kathrin Jaeger, Petra Båth, Daniel James, Anastasya Shilova, Michael Heymann, Manfred Burghammer, Cecilia Wickstrand, Garrett Nelson, Uwe Weierstall, Joerg Standfuss, Nadia A. Zatsepin, Przemyslaw Nogly, Haiguang Liu, John David Spence, Paul Scherrer Inst, Lab Biomol Res, CH-5232 Villigen, Switzerland, Arizona State University [Tempe] (ASU), DESY, Ctr Free Electron Laser Sci, D-22607 Hamburg, Germany, European Synchrotron Radiation Facility (ESRF), Scripps Research Institute, Ctr Ultrafast Imaging, D-22607 Hamburg, Germany, University of Gothenburg (GU), Univ Hamburg, Dept Phys, D-22607 Hamburg, Germany, Department of Biology [ETH Zürich] (D-BIOL), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Physics [Tempe], Diamond Light Source, Membrane Prot Lab, Chilton OX11 0DE, Oxon, England, Rutherford Appleton Lab, Didcot OX11 0FA, Oxon, England, Univ London Imperial Coll Sci Technol & Med, Dept Life Sci, London, England, and Universiteit Gent = Ghent University [Belgium] (UGENT)
- Subjects
Materials science ,Physics::Optics ,Synchrotron radiation ,02 engineering and technology ,Biochemistry ,law.invention ,Quantitative Biology::Subcellular Processes ,03 medical and health sciences ,law ,protein crystallography ,Proton transport ,[CHIM]Chemical Sciences ,ddc:530 ,General Materials Science ,lcsh:Science ,030304 developmental biology ,Physics::Biological Physics ,Quantitative Biology::Biomolecules ,0303 health sciences ,Millisecond ,biology ,bacteriorhodopsin ,lipidic cubic phases ,XFEL ,Resolution (electron density) ,Bacteriorhodopsin ,General Chemistry ,equipment and supplies ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Research Papers ,Synchrotron ,Crystallography ,Lipidic cubic phases ,Protein crystallography ,biological sciences ,X-ray crystallography ,Femtosecond ,biology.protein ,Physics::Accelerator Physics ,lcsh:Q ,lipids (amino acids, peptides, and proteins) ,0210 nano-technology - Abstract
Lipidic cubic phases (LCPs) have emerged as successful matrixes for the crystallization of membrane proteins. Moreover, the viscous LCP also provides a highly effective delivery medium for serial femtosecond crystallography (SFX) at X-ray free-electron lasers (XFELs). Here, the adaptation of this technology to perform serial millisecond crystallography (SMX) at more widely available synchrotron microfocus beamlines is described. Compared with conventional microcrystallography, LCP-SMX eliminates the need for difficult handling of individual crystals and allows for data collection at room temperature. The technology is demonstrated by solving a structure of the light-driven proton-pump bacteriorhodopsin (bR) at a resolution of 2.4 Å. The room-temperature structure of bR is very similar to previous cryogenic structures but shows small yet distinct differences in the retinal ligand and proton-transfer pathway., IUCrJ, 2 (2), ISSN:2052-2525
- Published
- 2015
50. Diffraction data of core-shell nanoparticles from an X-ray free electron laser
- Author
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Uwe Weierstall, Hsiang Ju Wang, Haiguang Liu, Dingjie Wang, Chun Ya Chiu, Brenda G. Hogue, Richard A. Kirian, Ilme Schlichting, Marc Messerschmidt, Andreas Menzel, Sabine Botha, Henry N. Chapman, Aliakbar Jafarpour, Fenglin Wang, Anton Barty, Petra Fromme, Christopher Kupitz, Elisabeth Hartmann, Sébastien Boutet, Shibom Basu, Garth J. Williams, Garrett Nelson, Mengning Liang, Robert M. Lawrence, Lutz Foucar, John C. H. Spence, Stephan Kassemeyer, Daniel James, Michael H. Huang, R. Bruce Doak, Raimund Fromme, Xuanxuan Li, and Robert L. Shoeman
- Subjects
Statistics and Probability ,Diffraction ,Data Descriptor ,Materials science ,Organogenesis ,Single particle analysis ,Nanoparticle ,02 engineering and technology ,Library and Information Sciences ,01 natural sciences ,Retina ,Education ,law.invention ,Optics ,law ,0103 physical sciences ,ddc:610 ,010306 general physics ,X-ray crystallography ,DNA methylation ,business.industry ,Scattering ,Resolution (electron density) ,Free-electron laser ,021001 nanoscience & nanotechnology ,Laser ,Corrigenda ,Computer Science Applications ,Femtosecond ,Nanoparticles ,Statistics, Probability and Uncertainty ,0210 nano-technology ,business ,Information Systems - Abstract
Scientific data 4, 170048 (2017). doi:10.1038/sdata.2017.48, X-ray free-electron lasers provide novel opportunities to conduct single particle analysis on nanoscale particles. Coherent diffractive imaging experiments were performed at the Linac Coherent Light Source (LCLS), SLAC National Laboratory, exposing single inorganic core-shell nanoparticles to femtosecond hard-X-ray pulses. Each facetted nanoparticle consisted of a crystalline gold core and a differently shaped palladium shell. Scattered intensities were observed up to about 7 nm resolution. Analysis of the scattering patterns revealed the size distribution of the samples, which is consistent with that obtained from direct real-space imaging by electron microscopy. Scattering patterns resulting from single particles were selected and compiled into a dataset which can be valuable for algorithm developments in single particle scattering research., Published by Springer Nature, London
- Published
- 2017
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