A SLAM Algorithm Based on Adaptive Cubature Kalman Filter

We need to predict mathematical model of the system and a priori knowledge of the noise statistics when traditional simultaneous localization and mapping (SLAM) solutions are used. However, in many practical applications, prior statistics of the noise are unknown or time-varying, which will lead to large estimation errors or even cause divergence. In order to solve the above problem, an innovative cubature Kalman filter-based SLAM (CKF-SLAM) algorithm based on an adaptive cubature Kalman filter (ACKF) was established in this paper. The novel algorithm estimates the statistical parameters of the unknown system noise by introducing the Sage-Husa noise statistic estimator. Combining the advantages of the CKF-SLAM and the adaptive estimator, the new ACKF-SLAM algorithm can reduce the state estimated error significantly and improve the navigation accuracy of the SLAM system effectively. The performance of this new algorithm has been examined through numerical simulations in different scenarios. The results have shown that the position error can be effectively reduced with the new adaptive CKF-SLAM algorithm. Compared with other traditional SLAM methods, the accuracy of the nonlinear SLAM system is significantly improved. It verifies that the proposed ACKF-SLAM algorithm is valid and feasible

Mapping knowledge of the stem cell in traumatic brain injury: a bibliometric and visualized analysis

BackgroundTraumatic brain injury (TBI) is a brain function injury caused by external mechanical injury. Primary and secondary injuries cause neurological deficits that mature brain tissue cannot repair itself. Stem cells can self-renewal and differentiate, the research of stem cells in the pathogenesis and treatment of TBI has made significant progress in recent years. However, numerous articles must be summarized to analyze hot spots and predict trends. This study aims to provide a panorama of knowledge and research hotspots through bibliometrics.MethodWe searched in the Web of Science Core Collection (WoSCC) database to identify articles pertaining to TBI and stem cells published between 2000 and 2022. Visualization knowledge maps, including co-authorship, co-citation, and co-occurrence analysis were generated by VOSviewer, CiteSpace, and the R package “bibliometrix.”ResultsWe retrieved a total of 459 articles from 45 countries. The United States and China contributed the majority of publications. The number of publications related to TBI and stem cells is increasing yearly. Tianjin Medical University was the most prolific institution, and Professor Charles S. Cox, Jr. from the University of Texas Health Science Center at Houston was the most influential author. The Journal of Neurotrauma has published the most research articles on TBI and stem cells. Based on the burst references, “immunomodulation,” “TBI,” and “cellular therapy” have been regarded as research hotspots in the field. The keywords co-occurrence analysis revealed that “exosomes,” “neuroinflammation,” and “microglia” were essential research directions in the future.ConclusionResearch on TBI and stem cells has shown a rapid growth trend in recent years. Existing studies mainly focus on the activation mechanism of endogenous neural stem cells and how to make exogenous stem cell therapy more effective. The combination with bioengineering technology is the trend in this field. Topics related to exosomes and immune regulation may be the future focus of TBI and stem cell research

Muscular kevlar aerogel tapes attractive to thermal insulation fabrics

Kevlar aerogel is a kind of easy-casting nano-porous material with the characteristics of low density, high porosity, low thermal conductivity, high specific surface area, etc. It can serve as functional fibers and has a bright future in the field of thermal insulation after being processed into fabrics. To improve the tensile power of aerogel fibers to bear more loads while maintaining their flexibility for further braiding, a series of Kevlar aerogel tapes were fabricated in this study by using flattened needles. It is observed that the resultant aerogel tapes show a spindle-like cross section, and have greatly improved load-bearing capability with muscular tensile strength up to 2.07 MPa. The use of a larger needle is conductive to preparing aerogel tapes that are more attractive in load-bearing, and increasing Kevlar concentration tends to result in more muscular tapes with improved breaking stress but reduced elasticity. Besides, these tapes also inherit the excellent thermal stability and char-forming ability of Kevlar, starting to decompose at around 500°C and producing carbon residue more than 40% of their initial weight at 700°C. In addition, these Kevlar aerogel tapes also perform well in terms of thermal insulation. When exposed to a hot plate of 300 °C, the fabric braided from these aerogel tapes show a considerable temperature drop per unit thickness as high as 120°C mm−1. It can be envisaged that the developed aerogel tapes with muscular tensile strength and their fabric products will be promising for high-temperature thermal insulation applications, such as being used as the insulation layer for thermal protective clothing

Multiple Frequency Bands Analysis of Large Scale Intrinsic Brain Networks and Its Application in Schizotypal Personality Disorder

The human brain is a complex system composed by several large scale intrinsic networks with distinct functions. The low frequency oscillation (LFO) signal of blood oxygen level dependent (BOLD), measured through resting-state fMRI, reflects the spontaneous neural activity of these networks. We propose to characterize these networks by applying the multiple frequency bands analysis (MFBA) to the LFO time courses (TCs) resulted from the group independent component analysis (ICA). Specifically, seven networks, including the default model network (DMN), dorsal attention network (DAN), control executive network (CEN), salience network, sensorimotor network, visual network and limbic network, are identified. After the power spectral density (PSD) analysis, the amplitude of low frequency fluctuation (ALFF) and the fractional amplitude of low frequency fluctuation (fALFF) is determined in three bands: <0.1 Hz; slow-5; and slow-4. Moreover, the MFBA method is applied to reveal the frequency-dependent alternations of fALFF for seven networks in schizotypal personality disorder (SPD). It is found that seven networks can be divided into three categories: the advanced cognitive networks, primary sensorimotor networks and limbic networks, and their fALFF successively decreases in both slow-4 and slow-5 bands. Comparing to normal control group, the fALFF of DMN, DAN and CEN in SPD tends to be higher in slow-5 band, but lower in slow-4. Higher fALFF of sensorimotor and visual networks in slow-5, higher fALFF of limbic network in both bands have been observed for SPD group. The results of ALFF are consistent with those of fALFF. The proposed MFBA method may help distinguish networks or oscillators in the human brain, reveal subtle alternations of networks through locating their dominant frequency band, and present potential to interpret the neuropathology disruptions

Single-cell analysis reveals specific neuronal transition during mouse corticogenesis

Background: Currently, the mechanism(s) underlying corticogenesis is still under characterization.Methods: We curated the most comprehensive single-cell RNA-seq (scRNA-seq) datasets from mouse and human fetal cortexes for data analysis and confirmed the findings with co-immunostaining experiments.Results: By analyzing the developmental trajectories with scRNA-seq datasets in mice, we identified a specific developmental sub-path contributed by a cell-population expressing both deep- and upper-layer neurons (DLNs and ULNs) specific markers, which occurred on E13.5 but was absent in adults. In this cell-population, the percentages of cells expressing DLN and ULN markers decreased and increased, respectively, during the development suggesting direct neuronal transition (namely D-T-U). Whilst genes significantly highly/uniquely expressed in D-T-U cell population were significantly enriched in PTN/MDK signaling pathways related to cell migration. Both findings were further confirmed by co-immunostaining with DLNs, ULNs and D-T-U specific markers across different timepoints. Furthermore, six genes (co-expressed with D-T-U specific markers in mice) showing a potential opposite temporal expression between human and mouse during fetal cortical development were associated with neuronal migration and cognitive functions. In adult prefrontal cortexes (PFC), D-T-U specific genes were expressed in neurons from different layers between humans and mice.Conclusion: Our study characterizes a specific cell population D-T-U showing direct DLNs to ULNs neuronal transition and migration during fetal cortical development in mice. It is potentially associated with the difference of cortical development in humans and mice

DIA-Based Quantitative Proteomics Reveals the Protein Regulatory Networks of Floral Thermogenesis in Nelumbo nucifera

The sacred lotus (Nelumbo nucifera) can maintain a stable floral chamber temperature between 30 and 35 °C when blooming despite fluctuations in ambient temperatures between about 8 and 45 °C, but the regulatory mechanism of floral thermogenesis remains unclear. Here, we obtained comprehensive protein profiles from receptacle tissue at five developmental stages using data-independent acquisition (DIA)-based quantitative proteomics technology to reveal the molecular basis of floral thermogenesis of N. nucifera. A total of 6913 proteins were identified and quantified, of which 3513 differentially abundant proteins (DAPs) were screened. Among them, 640 highly abundant proteins during the thermogenic stages were mainly involved in carbon metabolism processes such as the tricarboxylic acid (TCA) cycle. Citrate synthase was identified as the most connected protein in the protein-protein interaction (PPI) network. Next, the content of alternative oxidase (AOX) and plant uncoupling protein (pUCP) in different tissues indicated that AOX was specifically abundant in the receptacles. Subsequently, a protein module highly related to the thermogenic phenotype was identified by the weighted gene co-expression network analysis (WGCNA). In summary, the regulation mechanism of floral thermogenesis in N. nucifera involves complex regulatory networks, including TCA cycle metabolism, starch and sucrose metabolism, fatty acid degradation, and ubiquinone synthesis, etc

Exploring technological application for artistic practices in filigree jewellery design development

With the advancement of 3D printing, more and more researchers demonstrate this digital techniques' growing importance in jewellery design and development. Previous research in this context has established the foundations for further enquiry in technological innovation in jewellery but has not been advanced significantly in filigree jewellery. This artistic research considers how Jewellery Computer Aided Design (JCAD), and 3D-printing contributes to reinvigorating Chinese cultural heritage through new filigree jewellery design and making. The research explores the potential for existing 3D printing technology for the reproduction of filigree jewellery that is imbued with Chinese cultural heritage values and the micro-details associated with the practice as it has evolved in China. Following this, the study seeks to answer the following research question: How can traditional filigree techniques reproduce through JCAD and 3D printing, impact on the development of filigree jewellery design based on traditional Chinese cultures?The thesis is supported by a range of theoretical and experimental qualitative methods associated with research in craft, design and artistic research. These methods include hypothesizing, historical and theoretical studies, jewellery design and making, exhibitions and interviews with experts (using Delphi Method) in the field, including thematic analysis (NVivo). The research data was collected qualitatively, categorised into objective and subjective data and illustrated through designs, texts, tables, and images. Experimentation and explorations of 3D printing technology in filigree jewellery practice work is presented as a body of artistic research that responds to the research questions. The aim is to test how existing 3D printing technology can reproduce traditional filigree handmade characteristics. Hence, experimental practice has been undertaken to demonstrate the use of existing 3D printed technology for reproducing historic, hand-made filigree characteristics as closely as possible.The analysis of historical and contemporary approaches has been informed by designing, hands-on making, 3D printing, and casting a series of filigree jewellery pieces. The potential for the practical application of this method was analysed through making, experiments, 3D printed jewellery objects, that are manifested in outputs exhibited at Loughborough University, and through exhibitions in the UK, Italy and China. Firstly, the findings and results were analysed in qualitative contexts, through experimentation into how JCAD and 3D printing can support filigree design and production. Secondly, through exploring this novel practice's capacity for enhancing jewellery design development based on Ming dynasty filigree jewellery and traditional Chinese culture based on the Wuxing (五行) theory. The contribution to knowledge is comprised of two key aspects summarized as follows. First, the outcomes of practice-based research form a significant part of the findings in this study. This not only includes the final designs depicted and discussed in chapter 6, but also experimental pieces generated during the whole process (such as the leaves and butterfly in chapter 5). These review new technical considerations in the representation and reproduction of filigree jewellery. Second, the argument challenges the Chinese cultural heritage perspective that filigree was invented in the Han (汉) dynasty. Through explaining why this Chinese common view is untrue, this provides the historical context and platform for fresh insights for the application of new technology in filigree jewellery design to be demonstrated. Most importantly, this previously neglected view is essential for learning filigree jewellery design in China. Therefore, all these outcomes respond to the central research question and form the core of this research.</p

Simulation of Cross-Correlated Random Fields for Transversely Anisotropic Soil Slope by Copulas

Multi-source uncertainties yielded by randomness, spatial variability and cross-correlation of soil parameters severely affect the realization of random fields. However, current studies rarely account for these simultaneously, leading to inevitable bias in random field simulation and subsequent structure analysis. In this paper, copula-based cross-correlated random fields for transversely anisotropic soil slope are proposed. Firstly, based on the traditional probabilistic method and random field theory, the effect of the cross-correlation of soil parameters on the random field is comprehensively analyzed. Then copulas, which mainly characterize the dependent structures of random variables, are further expanded to connect multivariate random fields. Four special algorithms associated with Gaussian, Frank, Plackett and No. 16 copulas are subsequently developed. At last, the performance and effectiveness of copula-based cross-correlated random fields are illustrated by means of assumed and engineering slope cases. The results show that the proposed method is amenable to characterizing spatial variability comprising multiple cross-correlated soil parameters of transversely anisotropic slope. Soil profiles can be represented with a relatively high accuracy. Moreover, the performance of copula-based CCRF is simultaneously governed by margins, cross-correlated coefficients and copulas. The proper selection of these crucial factors can considerably reduce multi-source uncertainties. Overall, the proposed method could provide a useful guideline for accurately modeling cross-correlation random fields of soil slope