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In this article, we introduced a novel definition for a class of extended Nussbaum functions that have looser requirements than the traditional Nussbaum function. The extended Nussbaum function achieves comparable performance to the traditional Nussbaum function while addressing the challenges of unknown control directions and time‐varying actuator faults. We then provide a specific example function based on the extended Nussbaum function definition. Unlike the traditional Nussbaum function, which oscillates with fixed frequency and constantly increasing amplitude, this example function constrains the amplitude and oscillates with decreasing frequency. Consequently, its amplitude and derivative remain bounded. The oscillation of the system caused by the too large amplitude of the traditional Nussbaum function can be avoided. Furthermore, this example function is constructed using portions of elliptic curve. As a result, it is continuous and differentiable, in contrast to the normal decreasing‐frequency Nussbaum function using trigonometric function, which is only continuous. The overall closed‐loop system's global stability and asymptotic convergence of system states are successfully achieved. Simulation results demonstrate the effectiveness of the proposed function. [ABSTRACT FROM AUTHOR]

Remote sensing indices are widely used in various fields of geoscience research. However, there are limits to how effectively the knowledge of indices can be managed or analyzed. One of the main problems is the lack of ontology models and research on indices, which makes it difficult to acquire and update knowledge in this area. Additionally, there is a lack of techniques to analyze the mathematical semantics of indices, making it difficult to directly manage and analyze their mathematical semantics. This study utilizes an ontology and mathematical semantics integration method to offer a novel knowledge graph for a remote sensing index knowledge graph (RSIKG) so as to address these issues. The proposed semantic hierarchical graph structure represents the indices of knowledge with an entity-relationship layer and a mathematical semantic layer. Specifically, ontologies in the entity-relationship layer are constructed to model concepts and relationships among indices. In the mathematical semantics layer, index formulas are represented using mathematical semantic graphs. A method for calculating similarity for index formulas is also proposed. The article describes the entire process of building RSIKG, including the extraction, storage, analysis, and inference of remote sensing index knowledge. Experiments provided in this article demonstrate the intuitive and practical nature of RSIKG for analyzing indices knowledge. Overall, the proposed methods can be useful for knowledge queries and the analysis of indices. And the present study lays the groundwork for future research on analysis techniques and knowledge processing related to remote sensing indices. [ABSTRACT FROM AUTHOR]

Geographic registration (geo-registration) is a crucial foundation for augmented reality (AR) map applications. However, existing methods encounter difficulties in aligning spatial data with the ground surface in complex outdoor scenarios. These challenges make it difficult to accurately estimate the geographic north orientation. Consequently, the accuracy and robustness of these methods are limited. To overcome these challenges, this paper proposes a rotation-invariant estimation method for high-precision geo-registration in AR maps. The method introduces several innovations. Firstly, it improves the accuracy of generating heading data from low-cost hardware by utilizing Real-Time Kinematic GPS and visual-inertial fusion. This improvement contributes to the increased stability and precise alignment of virtual objects in complex environments. Secondly, a fusion method combines the true-north direction vector and the gravity vector to eliminate alignment errors between geospatial data and the ground surface. Lastly, the proposed method dynamically combines the initial attitude relative to the geographic north direction with the motion-estimated attitude using visual-inertial fusion. This approach significantly reduces the requirements on sensor hardware quality and calibration accuracy, making it applicable to various AR precision systems such as smartphones and augmented reality glasses. The experimental results show that this method achieves AR geo-registration accuracy at the 0.1-degree level, which is about twice as high as traditional AR geo-registration methods. Additionally, it exhibits better robustness for AR applications in complex scenarios. [ABSTRACT FROM AUTHOR]

Circular RNAs (circRNAs) have been shown to have critical roles in developing cancer and treatment resistance in an increasing body of research. The aim was to look into the functions and processes of hsa_circ_0003220 in the non-small cell lung cancer (NSCLC) chemoresistance. The NSCLC cell lines H460 and A549 were employed in present work. hsa_circ_0003220, miR-489-3p, and insulin-like growth factors (IGF1) mRNA levels were assessed with a quantitative real time polymerase chain reaction (qRT-PCR). The cisplatin, docetaxel, and paclitaxel (PTX) resistances were determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the enzyme linked immunosorbent assay (ELISA) test measured IGF1 expression. In order to corroborate the miR-489-3p relation with hsa_circ_0003220 or IGF1, a dual-luciferase reporter method was applied. The level of hsa_circ_0003220 was raised in cells and tissues from PTX-resistant (PR) NSCLC. In PR NSCLC cells, hsa_circ_0003220 knockdown reduced chemoresistance. For the purpose of the mechanism study, hsa_circ_0003220 knockdown substantially reduced IGF1 expression via miR-489-3p sponging, reducing chemoresistance in PR NSCLC cells. By controlling the miR-489-3p/IGF1 axis, hsa_circ_0003220 knockdown helped NSCLC overcome chemoresistance, suggesting a potential circRNA-targeted therapy for the disease. [ABSTRACT FROM AUTHOR]

This article studies the leader‐following attitude coordination problem of a group of rigid spacecraft subject to communication constraint, disturbances and uncertain control coefficient matrices. A fully distributed adaptive anti‐disturbance attitude coordinated control scheme with event‐triggering mechanism is developed. First, the event‐triggered adaptive distributed observer is designed for each follower to estimate the leader's information without continuous communication requirement. Based on the estimated information, the adaptive anti‐disturbance attitude tracking controller is designed such that asymptotic coordinated tracking can be achieved under additive disturbances and actuators' partial loss of efficiency. The proposed control scheme ensures that all the closed‐loop signals are bounded and the positive lower bound of inter‐event times exists in each subsystem. Simulation results illustrate the effectiveness and flexibility of the proposed control scheme. [ABSTRACT FROM AUTHOR]

In this paper, the effect of a new mixed collector sodium oleate (NaOl)/tert dodecyl mercaptan (TDM) on the separation of diaspore and kaolinite at 283 K was investigated. The molar ratio of NaOl to TDM is 8:2. The properties of the mixed collector and its adsorption mechanism on diaspore and kaolinite were studied by surface tension measurements, Zeta potential determinations and XPS analysis. The flotation results show that the mixed collector NaOl/TDM has a good collection ability for diaspore and a good selectivity for kaolinite at low temperatures. Therefore, the mixed collector NaOl/TDM can effectively separate diaspore and kaolinite under alkaline conditions at 283 K. The results of surface tension measurements show that the molecular density, hydrophobic association ability and collection ability of the mixed collector NaOl/TDM are better than those of the single collector at 283 K. In addition, the formation of a micelle effect of the mixed collector NaOl/TDM has a synergistic effect, which improves the reagent activity at low temperatures with the flotation effect enhanced. The results of the Zeta potential determinations and XPS analysis show that the total adsorption capacity of the mixed collector NaOl/TDM on the surface of the diaspore at low temperatures is higher than that of NaOl, and the adsorption capacity on the surface of kaolinite is similar to that of NaOl. The mixed collector NaOl/TDM may be adsorbed on the surface of diaspore and kaolinite by a hydrogen bond at 283 K. [ABSTRACT FROM AUTHOR]

In this article, a composite anti-disturbance control of disturbance rejection and attenuation for a class of nonlinear positive systems is proposed for the first time to achieve both positivity and stability. The disturbance observer-based control (DOBC) method is utilized to compensate for the effects of the modeled disturbances, while the $L_{1}$ control strategy is adopted to suppress the effects of the disturbances which are not compensable to satisfy the $L_{1}$ index performance. Besides, two analysis schemes of the closed-loop system are presented. The first scheme is commonly used and is easy for analysis, but it has some conservativeness. The second scheme is proposed novelly with less conservativeness, which releases the positivity constraint of disturbance estimation errors. The corresponding theorems and algorithms are proposed for necessary conditions and solutions. Finally, two examples are presented to illustrate the effectiveness of the proposed control schemes. [ABSTRACT FROM AUTHOR]

Increasingly complex vector map applications and growing multi-source spatial data pose a serious challenge to the accuracy and efficiency of vector map visualization. It is true especially for real-time and dynamic scene visualization in mobile augmented reality, with the dramatic development of spatial data sensing and the emergence of AR-GIS. Such issues can be decomposed into three issues: accurate pose representation, fast and precise topological relationships computation and high-performance acceleration methods. To solve these issues, a novel quaternion-based real-time vector map visualization approach is proposed in this paper. It focuses on precise position and orientation representation, accurate and efficient spatial relationships calculation and acceleration parallel rendering in mobile AR. First, a quaternion-based pose processing method for multi-source spatial data is developed. Then, the complex processing of spatial relationships is mapped into simple and efficient quaternion-based operations. With these mapping methods, spatial relationship operations with large computational volumes can be converted into efficient quaternion calculations, and then the results are returned to respond to the interaction. Finally, an asynchronous rendering acceleration mechanism is also presented in this paper. Experiments demonstrated that the method proposed in this paper can significantly improve vector visualization of the AR map. The new approach, when compared to conventional visualization methods, provides more stable and accurate rendering results, especially when the AR map has strenuous movements and high frequency variations. The smoothness of the user interaction experience is also significantly improved. [ABSTRACT FROM AUTHOR]

In this article, a novel distributed attitude coordination control scheme is proposed for a group of rigid spacecraft with unknown disturbances. The communication topology is described by a general directed graph, and the leader's attitude is available to only a small fraction of followers. Different from existing attitude coordination control schemes, here an event-triggered communication strategy without Zeno phenomenon is designed, which avoids continuous communication between neighboring spacecraft and considerably reduces the communication burden. Moreover, a nonlinear observer is constructed for each follower, which enables us to estimate and compensate for a large class of disturbances exactly. The proposed scheme is able to ensure the boundedness of all closed-loop signals and steer the attitude tracking errors into an arbitrarily small residual set, regardless of the intermittent communication. Simulation results illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, a novel adaptive neural network (NN) control scheme is proposed for a class of nonlinear systems with unknown control direction. By introducing some differentiable functions and high-order Lyapunov functions, the obstacle caused by unknown control direction in NN control is successfully circumvented and all closed-loop signals are shown to be uniformly bounded up to infinite time. Meanwhile, by introducing an error transformation technique, it is rigorously proved that the argument of the unknown nonlinearities remains within a compact set which can be explicitly calculated a priori, making the NN approximation always valid. Moreover, with the aid of a bound estimation approach, we effectively compress the impact of approximation errors and external disturbances and steer the tracking error into a predefined small residual set. Simulation results illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper is devoted to attitude tracking control of fractionated spacecraft with wireless communication. We consider the practical case that the spacecraft suffers from uncertain inertia parameters, external disturbances, and even unknown and time-varying actuator faults. Within the framework of the backstepping method, a novel event-triggered adaptive fault-tolerant control scheme is proposed. In our design, an event-triggering mechanism is introduced to determine the time instants for communication, which successfully avoids continuous communication and Zeno phenomenon. Then, with the aid of a bound estimation approach and a smooth function, the impacts of the actuator faults, as well as the network-induced error, are effectively compensated for. Moreover, by employing the prescribed performance control technique, it is shown that the attitude tracking errors can converge to predefined arbitrarily small residual sets with prescribed convergence rate and maximum overshoot, no matter if there exist unknown actuator faults. Compared with conventional adaptive attitude control schemes, the proposed scheme significantly reduces the communication burden, while providing high reliability and stable, rapid, and accurate response for attitude maneuvers. Simulation results are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In order to explore graphene oxide (GO) as a potential carrier or remover for flotation collectors in complex environments, the study investigated the individual and competitive adsorption processes of flotation collectors on GO using molecular dynamics (MD) simulations through 2-Methylpropoxymethanedithioate (CS), a xanthate-based collector, and Diethylthiophosphate (PS), an aerofloat-based collector. The distribution of molecular conformations, center-of-mass distance calculations, radial distribution function analysis, hydrogen bonding analysis and interaction force calculations were used to conclude that when CS and PS were under competing adsorption systems, both molecules adsorb more strongly on the GO surface than under individual adsorption systems, and CS molecules could promote the adsorption of PS. Coulomb interactions between the two organic molecules were the driving force for them to show a more dispersive effect under competitive adsorption conditions, and van der Waals forces were the main reason why both molecules can adsorb on the GO surface. This work provided some theoretical implications for improving the flotation environment as well as industrial wastewater treatment. [Display omitted] • Graphene oxide was introduced into the study of flotation environments by means of molecular dynamics simulations. • Graphene oxide was expected to be used as a carrier or remover for flotation reagents. • The coexistence of multiple collector molecules can affect each other's adsorption on graphene oxide. • Coulomb and van der Waals forces exhibit different roles in the competitive adsorption system of reagents. [ABSTRACT FROM AUTHOR]

In this paper, an adaptive dynamic surface control scheme is proposed for a class of hypersonic flight vehicles with unknown elevator faults. By estimating the bounds of the fault uncertainties, the effect of the faults is successfully compensated for and each elevator is allowed to change among the healthy case and different faulty cases infinitely many times. The proposed scheme is free of the problem of explosion of complexity and is able to steer tracking errors into predefined arbitrarily small residual sets with prescribed convergence rates and maximum overshoots. Such features result in a simple flight control scheme which can be easily implemented with less computational burden, satisfactory tracking performance and high reliability. Simulation results illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, a novel adaptive fault-tolerant control (FTC) scheme is proposed for a class of hypersonic flight vehicles (HFVs) with input constraints and unknown inertial and aerodynamic parameters. As an advantage beyond existing adaptive FTC schemes for HFVs, we investigate a more practical and more challenging case that both the elevator and the throttle may suffer from unknown and time-varying faults. By introducing some smooth functions and a linear time-varying model and estimating the bounds of those time-varying uncertainties, the impact of the faults and the input constraints is effectively compensated for and stable altitude and velocity tracking is successfully achieved. Besides, with the aid of the dynamic surface control technique, the proposed scheme is free of the problem of explosion of complexity inherent in traditional backstepping design. Such features result in a simple flight control scheme that can be easily implemented with less computational burden and higher reliability. Simulation results are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, an output-feedback adaptive consensus tracking control scheme is proposed for a class of high-order nonlinear multi-agent systems. The agents are allowed to have unknown parameters, unknown nonlinearities, and input quantization simultaneously. The desired trajectory to be tracked is available for only a subset of agents, and only the relative outputs and the quantized inputs need to be measured or transmitted as signal exchange among neighbors regardless of the system order. By introducing a kind of high-gain K-filters and a smooth function, the effect among agents caused by the unknown nonlinearities is successfully counteracted, and all closed-loop signals are proved to be globally uniformly bounded. Moreover, it is shown that the tracking errors converge to a residual set that can be made arbitrarily small. Simulation results on robot manipulators are presented to illustrate the effectiveness of the proposed scheme. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The effect of temperature on the flotation behavior of sodium oleate on the surface of diaspore was investigated by using molecular dynamics (MD) simulations at three selected temperatures of 278.15 K, 303.15 K and 328.15 K. Conformational analysis, RDF analysis, hydrogen bonds statistics, SASA calculations and interaction energy analysis revealed that a certain range of temperature increase was beneficial for flotation, and the right temperature could yield better reagent dispersion and better mineral-reagent interactions. It was also noted that the enhanced molecular motion due to increased temperature may negatively affect the adsorption of the reagent on the mineral surface. The present study has theoretical implications for the effect of temperature on the flotation behavior of ionic surfactants on mineral surfaces. • The effect of temperature on flotation was studied by molecular dynamics. • Different temperatures showed different performances of sodium oleate in collecting diaspore. • A suitable temperature could make the sodium oleate better dispersed and distributed. • Higher temperature did not necessarily lead to a better flotation environment. [ABSTRACT FROM AUTHOR]

In this paper, a decentralized output-feedback adaptive control scheme is proposed for a class of interconnected nonlinear systems with input quantization. Both logarithmic quantizers and improved hysteretic quantizers are studied, and a linear time-varying model is introduced to handle the difficulty caused by quantization. The proposed scheme allows the parameters of the quantizers to be freely changed during operation, and can guarantee global stability of the overall closed-loop system regardless of the coarseness of the quantizers and the existence of interactions among subsystems. Moreover, with the aid of a kind of high-gain K-filters, it is shown that all tracking errors converge to a residual set which can be made arbitrarily small by adjusting some design parameters. Simulation results are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, a decentralized output-feedback adaptive backstepping control scheme is proposed for a class of interconnected nonlinear systems with unknown actuator failures. By introducing a kind of high-gain K -filters, a bound estimation approach and some smooth functions, the effect of actuator failures and interactions among subsystems is successfully compensated for and the actuators are allowed to change among the normal operation case and different failure cases infinitely many times. The proposed scheme is able to guarantee the global stability of the overall closed-loop system, regardless of the possibly infinite number of unknown actuator failures. An initialization technique is also introduced so that the L ∞ performance of tracking errors can be adjusted no matter if there exist unknown actuator failures. Simulation results performed on double inverted pendulums are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, a new adaptive compensation control scheme is proposed for a class of nonlinear systems with unknown parameters and unknown actuator failures. The normal operation case and different failure cases of actuators are unified through a time-varying model. By introducing a smooth function, an integrable auxiliary signal, and a bound estimation approach, the effect of failures is successfully compensated for, and the total number of failures is not restricted to be finite. It is shown that all closed-loop signals are globally uniformly bounded, and the tracking error converges to zero asymptotically regardless of the possibly infinite number of actuator failures. An application to the longitudinal dynamic model of a twin otter aircraft is presented to illustrate the effectiveness of the proposed scheme. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a novel robust adaptive neural control scheme is proposed for a class of uncertain multi-input multi-output nonlinear systems. The proposed scheme has the following main features: (1) a kind of Hurwitz condition is introduced to handle the state-dependent control gain matrix and some assumptions in existing schemes are relaxed; (2) by introducing a novel matrix normalisation technique, it is shown that all bound restrictions imposed on the control gain matrix in existing schemes can be removed; (3) the singularity problem is avoided without any extra effort, which makes the control law quite simple. Besides, with the aid of the minimal learning parameter technique, only one parameter needs to be updated online regardless of the system input–output dimension and the number of neural network nodes. Simulation results are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, an adaptive dynamic surface control scheme is proposed for a class of multi-input multi-output (MIMO) nonlinear time-varying systems. By fusing a bound estimation approach, a smooth function and a time-varying matrix factorisation, the obstacle caused by unknown time-varying parameters is circumvented. The proposed scheme is free of the problem of explosion of complexity and needs only one updated parameter at each design step. Moreover, all tracking errors can converge to predefined arbitrarily small residual sets with a prescribed convergence rate and maximum overshoot. Such features result in a simple adaptive controller which can be easily implemented in applications with less computational burden and satisfactory tracking performance. Simulation results are presented to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM PUBLISHER]

The design of output constrained control system for unmanned aerial vehicles deployed in confined areas is an important issue in practice and not taken into account in many autopilot systems. In this study, the authors address a neural networks‐based adaptive trajectory tracking control algorithm for multi‐rotors systems in the presence of various uncertainties in their dynamics. Given any sufficient smooth and bounded reference trajectory input, the proposed algorithm achieves that (i) the system output (Euclidean position) tracking error converges to a neighbourhood of zero and furthermore (ii) the system output remains uniformly in a prescribed set. Instead of element‐wise estimation, a norm estimation approach of unknown weight vectors is incorporated into the control system design to relieve the onboard computation burden. The convergence property of the closed‐loop system subject to output constraint is analysed via a symmetric barrier Lyapunov function augmented with several quadratic terms. Simulation results are demonstrated on a quadrotor model to validate the effectiveness of the proposed algorithm. [ABSTRACT FROM AUTHOR]

Molecular dynamics (MD) simulation was performed to study the sodium oleate/sodium abietate/water system especially on the liquid-gas interface during the process of minerals separation by air flotation. Some representative parameters, such as number density, 2D number density, diffusion coefficient, surface tension, number of hydrogen bonds and solvent accessible surface area were calculated. The simulation results showed that the mixture of sodium oleate and sodium abietate in a suitable ratio contributed to the surface activity of the gas-liquid interface, which could be derived from the distribution state of the molecules. The efficient distribution of surfactants at the interface could reduce the agent loss of froth flotation, reflecting the superiority of mixed-use of surfactants. The self-dispersion of the active groups and the sufficient effective contact area with water revealed the feasibility of this conventional method. The ratio of mixed surfactants with the best flotation activity was NaOL/NaAB = 2/1. These results demonstrated a certain extent of synergy between sodium oleate and sodium abietate at the air/water interface. [Display omitted] [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to investigate the relationship between matrix metalloproteinase-7 (MMP-7) expression and the clinical and pathological characteristics of salivary adenoid cystic carcinomas (SACC) of the palatal minor salivary gland. Methods: In this study, 58 samples of SACC and 10 samples of normal salivary gland tissue were examined. Immunohistochemistry was used to detect MMP-7 and vascular endothelial growth factor A (VEGF-A) expression in SACC and normal tissues. The clinical and pathological characteristics of the patients with SACC were collected. Results: Of the 58 SACC samples, 44 were positive for MMP-7, and the expression rate was 75.9%. No expression was detected in the 10 normal salivary gland tissues. The level of MMP-7 expression in the SACC and normal samples was significantly different. The level of expression of MMP-7 in the SACC samples did not correlate with age, sex or pathological type but did correlate with pathological grade, nerve infiltration and clinical stage. There was a positive correlation between VEGF-A and MMP-7 expression. Conclusions: The SACC samples showed high expression of MMP-7, which was associated with tumour differentiation, invasiveness and clinical stage. The detection of MMP-7 positively correlated with the detection of VEGF-A in SACC. [ABSTRACT FROM AUTHOR]

SUMMARY This paper is devoted to output-feedback adaptive control for a class of multivariable nonlinear systems with both unknown parameters and unknown nonlinear functions. Under the Hurwitz condition for the high-frequency gain matrix, a robust adaptive backstepping control scheme is proposed, which is able to guarantee the [ABSTRACT FROM AUTHOR]

In this article, a novel output-feedback adaptive dynamic surface control scheme is proposed for linear time-invariant multivariable plants based on the norm estimation of unknown parameter matrices. Besides avoiding the explosion of complexity problem in traditional multivariable backstepping design, the proposed scheme has the following features: (1) only one parameter needs to be updated on-line regardless of the plant order and input–output dimension, (2) only the Hurwitz condition is required for the high-frequency gain matrix and (3) the ℒ∞ performance of the tracking error can be guaranteed. It is shown that all signals of the closed-loop system are semi-globally uniformly bounded. Simulation results are given to illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

Objective: To explore the VEGF-A expression in salivary gland adenoid cystic carcinoma tissues and detect the relationship between the mechanism of occurrence, development and metastasis of jaws with salivary gland adenoid cystic carcinoma and VEGF-A expression. Methods: Paraffin samples from 58 cases of SACC of the palate and ten cases of normal salivary gland tissues were collected. The expression levels of VEGF-A protein were detected using the immunohistochemistry EnVision system. Results: Among the 58 cases, there were 20 cases of the cribriform type, 17 cases of the tubular type, and 21 cases of the solid type. There were 9 cases with lymph node metastasis and 21 cases without lymph node metastasis. And there were 8 cases of T1, 15 cases of T2, and 7 cases of T3/T4. The positive expression rate of VEGF-A in SACC of the palate was 74.1%, which was higher than that found in normal salivary gland tissues (10%). The VEGF-A was localized in the cytoplasm/cell membrane. Conclusion: VEGF-A is highly expressed in SACC of the palate. The level of expression is closely related to the pathological grade, lymph node metastasis, and clinical stage of the tumor, and it can thus be used as an important indicator for judging the biological behavior of SACC of the palate. [ABSTRACT FROM AUTHOR]

With the extensive application of big spatial data and the emergence of spatial computing, augmented reality (AR) map rendering has attracted significant attention. A common issue in existing solutions is that AR-GIS systems rely on different platform-specific graphics libraries on different operating systems, and rendering implementations can vary across various platforms. This causes performance degradation and rendering styles that are not consistent across environments. However, high-performance rendering consistency across devices is critical in AR-GIS, especially for edge collaborative computing. In this paper, we present a high-performance, platform-independent AR-GIS rendering engine; the augmented reality universal graphics library (AUGL) engine. A unified cross-platform interface is proposed to preserve AR-GIS rendering style consistency across platforms. High-performance AR-GIS map symbol drawing models are defined and implemented based on a unified algorithm interface. We also develop a pre-caching strategy, optimized spatial-index querying, and a GPU-accelerated vector drawing algorithm that minimizes IO latency throughout the rendering process. Comparisons to existing AR-GIS visualization engines indicate that the performance of the AUGL engine is two times higher than that of the AR-GIS rendering engine on the Android, iOS, and Vuforia platforms. The drawing efficiency for vector polygons is improved significantly. The rendering performance is more than three times better than the average performances of existing Android and iOS systems. [ABSTRACT FROM AUTHOR]

An in-situ generation of PEI-based 2D perovskite interlayers strategy is employed to improve the lattice match between NiO x and perovskites, thus suppressing interfacial defect formation to boost the efficiency and stability of NiO x -based inverted planar perovskite solar cells. • Applying an in-situ generated polyethylenimine-based 2D perovskite interlayer strategy. • Improving the lattice match between NiO x and perovskites and suppressing interfacial defect formation. • Boosting the efficiency and stability of NiO x -based inverted planar perovskite solar cells. Recently, NiO x -based inverted planar perovskite solar cells (PSCs) have achieved great progress. However, the lattice mismatch between NiO x hole-transport layers (HTLs) and perovskite active layers will result in interfacial defect formation, which severely influences device efficiency and stability. In this work, this is alleviated by coating of polyethylenimine cations (PEI•HI) on the surface of NiO x HTLs. The introduction of PEI•HI can not only effectively passivate the surface defects of NiO x films, but also induce the in-situ-generation of polyethylenimine (PEI)-based two-dimensional (2D) perovskite interlayers between NiO x and CH 3 NH 3 PbI 3 (MAPbI 3). Such PEI-based 2D perovskite interlayer can dramatically mitigate the lattice mismatch between NiO x and perovskites to suppress the interfacial defects formations and promote the high-quality crystal nucleation and growth of above perovskite films. Meanwhile, it is demonstrated that the molecular weights of PEI act the pivotal part in controlling the nucleation quality of perovskites. When employing PEI with molecular weight of 10,000 (PEI-1000), the high-crystalline perovskite film with large-sized grains and reduced interfacial defects is obtained and the champion PSC delivers a power conversion efficiency (PCE) of 19.23% with weak hysteresis effect and improved reproducibility and stability. Our work provides a promising approach to improve the lattice match between NiO x and perovskites for high-performance NiO x -based inverted planar PSCs. [ABSTRACT FROM AUTHOR]

In this article, we propose a novel event‐triggered control (ETC) method from the control input perspective. Different from existing results in which event conditions are designed based on the variation of system states, this method designs event conditions from the control input perspective, that is, based on the control input variations. Through this method, it is shown that for nonlinear systems, the commonly used input‐to‐state stable assumption can be removed. For linear systems, this method is shown equivalent to conventional results established based on state signals. Moreover, it provides flexibility in designing different event conditions for uncertain nonlinear systems. The effectiveness of the proposed method is demonstrated through two simulation examples. [ABSTRACT FROM AUTHOR]

Multivariable adaptive control with less prior information of the high-frequency gain matrix (HFGM) is a longstanding problem of both theoretical and practical importance. In this paper, a solution is presented by proposing a novel output-feedback adaptive backstepping control scheme. Our scheme only requires the leading principal minors of the HFGM to be nonzero and allows their signs to be unknown, which significantly relaxes the assumptions on the HFGM in conventional multivariable adaptive control schemes. To cope with the unknown signs, we propose novel Nussbaum functions with some nice properties and construct periodical intervals in which the effects of the multiple Nussbaum functions reinforce rather than counteract each other. With these efforts, global stability of the closed-loop system and asymptotical convergence to zero of the tracking error are successfully achieved. Simulation results illustrate the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

The use of plasticizers is crucial in enhancing the flexibility of engineering plastics. Currently, the primary plasticizers employed in poly(vinyl chloride) materials are nonrenewable phthalates. These exhibit a detrimental impact on the environment and human health owing to their toxic benzene ring structure. Consequently, the development of easily synthesizable, green plasticizers with excellent properties using biobased resources has been a long-standing objective in the field of resin plasticizing. Herein, we synthesized a branched lactic acid ester (BLAE) plasticizer using esterification and acid anhydride end-capping methods. Further, we investigated its application performance and oral toxicity. The abundance of polar ester groups in the oligolactic acid structure enables them to form secondary bonds with polymer chains. This results in a glass transition temperature is 59% less than that of pure poly(vinyl chloride), thereby improving the mechanical properties of the material. The addition of the BLAE plasticizer not only improved the thermal stability of the compound film but also effectively reduced the self-catalytic dehydrochlorination reaction of poly(vinyl chloride). This overcomes the limitations of unmodified poly(vinyl chloride), such as performance deterioration and color variation due to light exposure. Furthermore, the hydrophobicity of the compound film was substantially enhanced, resulting in outstanding antifouling and self-cleaning properties. These findings suggest that lactic acid-based plasticizer exhibits comparable or even superior overall performance when compared to commercially available plasticizers such as dioctyl phthalate and acetyl tributyl citrate. This work not only addresses the gap in the toxicity assessment of lactic acid plasticizers but also demonstrates their nontoxic characteristics in acute oral toxicity tests. This research offers novel insights into the green synthesis and functional development of biobased plasticizers, showcasing considerable potential for the substituting of dioctyl phthalate. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper addresses the relative position coordinated control problem for spacecraft formation flying under an undirected communication graph, whilst considering mass uncertainties, external disturbances, and limited communication resources. A new event-triggered information transmission mechanism is first presented, where each spacecraft only requires accessing to the states of neighbors intermittently. Subsequently, a novel event-based coordinated control scheme is proposed by combining a smooth adaptive projection rule that confines the parameter estimations to well-defined bounded convex hypercubes. Under the proposed control framework, the information exchange among spacecraft occurs only when the specified event is triggered, thereby significantly reducing the communication load and saving the onboard resources. Furthermore, a positive lower bound on interevent time intervals is guaranteed to exclude Zeno behavior. By virtue of Lyapunov stability analysis and graph theory, it is proved that the relative position tracking errors can converge to small invariant sets around the origin, and that all closed-loop signals are bounded, even in the presence of mass uncertainties and external disturbances. Finally, numerical simulations are given to evaluate the effectiveness and highlight the advantages of the developed control algorithm. [ABSTRACT FROM AUTHOR]

Robustness of positive systems with respect to disturbances is a challenging issue of both theoretical and practical importance. In this study, the stabilisation control problem of positive systems with disturbances is investigated. More generalised disturbances are considered here, including positive modelled disturbances and general disturbances. A disturbance observer is designed to estimate the disturbances and a sufficient and necessary condition for stabilisation is derived. For positive disturbances, a sufficient condition with the use of the convergence law for the existence of controller is proposed, and this problem can be formulated as a linear programming problem. Furthermore, the corresponding theory is expanded to generally modelled disturbances, which enriches the theories about anti‐disturbance control of positive systems. Meanwhile, the analysis is given in detail to promote the theoretical completeness, including conservations of hypothesis and positivity constraints of disturbance estimation values. Simulation results show that the proposed scheme can guarantee the positivity of systems and improve the system performances for generalised disturbances. [ABSTRACT FROM AUTHOR]

Secure guidance for missiles against cyber-attacks is an interesting topic of both theoretical and practical importance, but so far few results are available. In this paper, two multivariable secure guidance laws are proposed for precise strikes interceptors with cyber-attacks in guidance commands. Different engagement scenarios are studied in three-dimensional space. Against highly maneuvering targets, the proposed secure guidance law can guarantee some states related to the line-of-sight (LOS) angular rates to converge to zero within finite time, where the cyber-attacks are indirectly estimated and compensated with the aid of an attack observer. Moreover, against non-maneuvering targets with impact angle constraints, the proposed secure guidance law is designed based on the backstepping technique, where the cyber-attacks are directly estimated and compensated. Particularly, prescribed performance functions are introduced in the second guidance law to flexibly determine the convergence rates of the LOS angles. Numerical simulations are performed to illustrate the effectiveness of the proposed schemes. [ABSTRACT FROM AUTHOR]

An adaptive approximated inverse control scheme for a class of high-order nonlinear multi-agent systems with unknown control directions is proposed in this paper. The adaptive control problem under the case it is not required to be identical for the unknown control directions is solved by some novel Nussbaum functions and a monotonously increasing sequence, leading our multiple Nussbaum functions reinforce rather than counteract each other. Also, it is introduced in the design and analysis like some integrable auxiliary signals and a novel contradiction argument. Moreover, hysteresis nonlinearity is counteracted by constructing its approximated inverse compensator. With these efforts, stability analysis ensures that all the closed-loop system signals are uniformly bounded, and it is successfully achieved the asymptotic convergence of tracking error to zero, circumventing the obstacle caused by the unknown control directions. Experiment results illustrate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this paper, an observer-based fault-tolerant control scheme is proposed for the attitude stabilization of rigid spacecraft in the presence of actuator fault, configuration misalignment, input saturation and even external disturbances simultaneously. More specifically, an iterative learning observer is firstly developed to estimate the torque deviation and steer the estimation errors into some small residual sets. And also the detailed derivations of the observer are provided, along with a thorough analysis for the associated ultimate bounded stability and estimation error convergence property. Then, an integral-type sliding mode control law is designed to produce the three-axis virtual control signals with the desired performance for being distributed among the individual actuators. Under this, a robust control allocation algorithm is developed to map the virtual control demand onto individual actuator in an optimal manner, which takes into account the estimation uncertainties and ensures some fault-tolerant ability. The key feature of the proposed strategies is that the whole closed-loop fault tolerant control system can be guaranteed theoretically to be stable by the development of Lyapunov methodology. Numerical simulation results are presented to illustrate and highlight the fine performance benefits obtained using the proposed schemes. [ABSTRACT FROM AUTHOR]

This paper addresses the control problem of air-breathing hypersonic vehicles subject to input nonlinearities, aerodynamic uncertainties and flexible modes. An adaptive backstepping controller and a dynamic inverse controller are developed for the altitude subsystem and the velocity subsystem, respectively, where the former eliminates the problem of “explosion of terms” inherent in backstepping control. Moreover, a modified smooth inverse of the dead-zone is proposed to compensate for the dead-zone effects and reduce the computational burden. Based on this smooth inverse, an input nonlinear pre-compensator is designed to handle input saturation and dead-zone nonlinearities, which leads to a simpler control design for the altitude subsystem subject to these two input nonlinearities. It is proved that the proposed controllers can guarantee that all closed-loop signals are bounded and the tracking errors converge to an arbitrarily small residual set. Simulation results are carried out to demonstrate the effectiveness of the proposed control scheme. [ABSTRACT FROM AUTHOR]

In this study, after optimizing the extraction process of CPP (Codonopsis pilosula polysaccharides), CPPM (CPP microcapsules) were prepared. Subsequently, the structural characteristics and physicochemical properties were studied. The results showed that CPPM is a hollow sac-like structure with rough folds and protuberances and comes in spherical or ellipsoidal shapes with uniform particle size. CPPM has certain swelling degree, low hardness, good adhesion, and stability. Then, the effect of CPPM on wounds repair was investigated by a rat model. The results showed that CPPM could improve the wound healing rate. Histological evaluation showed CPPM could promote neovascularization and fibroblast proliferation. By investigating the healing mechanism, it was found that CPPM increased the hydroxyproline content in granulation tissue and had an excellent antioxidant ability, and then inhibited lipid peroxidation, in addition, it significantly increased the transcript levels of VEGF and miRNA-21 genes, indicating that CPPM play an influential role in vascular remodeling during wound healing by up-regulating the expression of VEGF and miRNA-21 genes. [ABSTRACT FROM AUTHOR]