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Objective: To observe the morphological characteristics of posterior scleral staphyloma (PSS) with or without macular retinoschisis (MRS) using optical coherence tomography (OCT). Additionally, the incidence and severity of other pathologic myopic maculopathy associated with posterior scleral staphyloma was also evaluated. Methods: General information and OCT imaging data from 440 patients with posterior scleral staphyloma (PSS) and the PSS curvature > 20×10−3 μm–1 were collected. These patients visited the Department of Ophthalmology at the First Affiliated Hospital of Harbin Medical University from January 2013 to June 2021. The obtained OCT images of PSS were analyzed using the Image J software to measure the curvature along the Bruch's membrane. The measured curvature was divided into four levels using the quartile method. The classification of macular retinoschisis (MRS) was based on the anatomical structure of the retina and the location of macular retinoschisis. Patients with PSS accompanied by MRS were assigned to the MRS group, while PSS patients without MRS were assigned to the non-MRS group. Additionally, typical OCT changes in other pathologic myopic maculopathy diseases, such as myopic choroidal neovascularization (mCNV), myopic traction maculopathy (MTM), and myopic foveoschisis (MF), were recorded and evaluated. Results: A total of 615 eyes (328 right eyes, 287 left eyes) from 440 patients (80 males and 360 females) were recruited in this study. The MRS group consisted of 159 patients (36.1%) with 190 eyes (30.9%), while the non-MRS group consisted of 281 patients (63.9%) with 425 eyes (69.1%). Both groups had a significantly higher proportion of female patients compared to male patients, and the right eye was more commonly affected than the left eye. In the MRS group, the prevalence of MRS increased progressively with the severity of PSS. Among the common posterior pole diseases, epiretinal membrane had the highest prevalence (33.2%), while lamellar macular hole had the lowest prevalence (5.3%). In the non-MRS group, the proportion of PSS in each group decreased progressively (except for an equal prevalence in the third and fourth levels) with increasing severity of PSS. Among the common posterior pole diseases, choroidal neovascularization had the highest prevalence (41.4%), while lamellar macular hole had the lowest prevalence (6.5%). When comparing the two groups, there were no significant differences in age, gender, and eye distribution. The MRS group had a higher prevalence of macular schisis, retinal detachment, and dome-shaped macula (17.9%, 14.2%, 14.8%) compared to the non-MRS group (11.3%, 9.2%, 9.6%). The non-MRS group had a significantly higher prevalence of choroidal neovascularization (41.4%) compared to the MRS group (12.6%), while there were no significant differences in the prevalence of epiretinal membrane and lamellar macular hole between the two groups. Conclusion: The prevalence of MRS increased progressively with the severity of PSS, and the MRS occurrence was positively correlated with PSS, which indicated that PSS may lead to MRS, while the proportion of PSS in each group decreases gradually with the severity of PSS in the non-MRS group decreased progressively (except for an equal prevalence in the third and fourth levels). In the MRS group, outer macular retinoschisiss were most relevant to posterior scleral staphyloma, and the prevalence of macular holes and retinal detachments was higher in the MRS group compared to the non-MRS group, indicating that MRS may further turn into complications such as macular holes and retinal detachments, which can significantly affect vision or lead to blindness. The prevalence of choroidal neovascularization (CNV) was significantly higher in the non-MRS group compared to the MRS group, suggesting that PSS with lower severity is more prone to develop into CNV. Dome-shaped macula (DSM) seems to play a protective role in the development of pathologic myopia, and abnormal changes in posterior scleral staphyloma curvature may be an important factor affecting the development and shape of DSM.

As an important ceramic matrix composite material, SiCp/Al ceramics have found extensive applications across several domains. However, the intricate nature of their material properties has resulted in a scarcity of scholarly investigations pertaining to the topic of ultrasonic vibration-assisted polishing (UVAP) of SiCp/Al ceramics. To solve this problem, a theoretical derivation of the material removal model (MRM) for UVAP SiCp/Al ceramics is presented in this paper. The selection of UVAP feeding speed is analyzed and discussed. The process parameters of UVAP of SiCp/Al ceramics are optimized based on the improved Hilbert's trajectory characteristics. According to the experimental results, high-quality machined surfaces can be obtained and the “fish scale” phenomenon can be avoided when the feeding speed is 0.015 m/s. Compared with the traditional trajectory, the improved Hilbert trajectory is easier to achieve uniform surface polishing. The introduction of ultrasonic amplitude (UA) can increase the material removal rate (MRR) by more than 21.6 % compared with the conventional polishing method. The maximum removal depth (MRD) increased by more than 27.76 % and the surface roughness (SR) is reduced by more than 76.45 %. The research results have an important application value for realizing efficient and high-quality polishing of SiCp/Al ceramics.

In the hot press process of high-performance bamboo-based fiber composites, there is a highly nonlinear relationship between the production parameters of hot press and the quality parameters of the finished boards. Consequently, it is challenging to accurately predict the quality of the boards based on the given production parameters, and it is equally difficult to preset the production parameters to achieve the desired board quality. The current approach relies on manual experience, which may result in subpar board quality and material waste. To address these issues, this paper proposes a bi-directional prediction model based on cHGWO-SCA-SVR, using the collaboration-based hybrid GWO-SCA optimizer to optimize the relevant parameters of the SVR, and then accurately predicting the production parameters and the quality of the finished boards in both directions. Finally the cHGWO-SCA-SVR prediction model achieves an average R2 of 0.9591 for the forward prediction model and lower MAE and MSE values compared to other models; for the reverse prediction model, it attains an average R2 of 0.9553 and lower MAE and MSE values compared to other models. The results demonstrate the superiority of the cHGWO-SCA-SVR prediction model in comparison with other existing models, proving its significance in guiding the production of high-performance bamboo-based fiber composites by hot compression.

Due to their outstanding properties, bamboo-based fiber composites are gaining significant traction in the fields of construction and decoration. Among the crucial process steps in their production, hot pressing stands out as a pivotal one. Temperature, being a key parameter in hot pressing, and its stability of control exert a profound impact on the finished mechanical properties and associated indices of bamboo-based fiber composites. In this investigation, we introduce an active disturbance rejection control (ADRC) methodology specifically tailored for the hot-pressing temperature of bamboo-based fiber composites. A mathematical model encompassing the motor, steam regulating valve, and, ultimately, the hot-pressing temperature is formulated, with the transfer functions at each level being precisely determined through parameter identification techniques. The simulation outcomes reveal that in the absence of signal interference, sinusoidal signal interference, or random signal interference, the ADRC method outperforms the traditional PID algorithm in the realm of hot-pressing temperature control for bamboo-based fiber composites. This approach effectively reduces the temperature fluctuations of the PID algorithm, thereby averting issues such as premature curing or board bursting. In summary, this study holds significant implications for enhancing the mechanical properties of bamboo-based fiber composites.

Summary: The endoplasmic reticulum (ER) is the largest intracellular endomembrane system; it shows dynamic changes upon environmental stress. To maintain ER morphology and homeostasis under stress, the excessive ER membrane and the associated unwanted proteins can be removed via ER-phagy. Although a few ER-phagy receptors have been reported in mammals and yeast, their functional counterparts in plants remain largely unexplored. Here, we report that the HVA22 family protein OsHLP1 is an uncharacterized ER-phagy receptor in rice (Oryza sativa L.). OsHLP1 interacts with OsATG8b and recruits ER subdomains and the cargo protein OsNTL6, a negative immune regulator, to autophagosomes upon infection with the fungus Magnaporthe oryzae, which substantially activates disease resistance in rice. AtHVA22J, an Arabidopsis thaliana OsHLP1 ortholog, induced similar ER-phagy in plants. Altogether, we unraveled a conservative protein family that may act as ER-phagy receptors in higher plants, and in particular, we highlighted their roles in rice immune responses.

Carbonatites possess the highest rare earth element (REE) concentrations among all magmatic rocks, yet the mechanisms governing the enrichment of REEs in carbonatites remain enigmatic. Carbonatite-hosted calcites provide crucial mineralogical and geochemical insights into addressing this matter. In this study, we present a dataset comprising major and trace elemental geochemistry, as well as in-situ Sr isotopic data, for two types of calcites from the Dalucao carbonatite complex in Sichuan Province, China. Our primary objective is to shed light on the origin of fertile carbonatites. These calcites are believed to have originated at different stages of carbonatitic evolution. Type I calcites, characterized by a euhedral granular texture and a homogeneous surface, crystallized at the early stage of carbonatite magmatism. In contrast, type II calcites, closely associated with bastnäsite in a paragenesis, formed within a fluid setting of hydrothermal overprinting. Both calcite types exhibit highly radiogenic (87Sr/86Sr)i ratios, ranging from 0.7059 to 0.7060 for type I calcites and 0.7059 to 0.7068 for type II calcites. The high Sr concentrations (3646–7315 µg/g for type I calcites and 6566–13,427 µg/g for type II calcites) and uniform Pb isotopic compositions (206Pb/204Pb ratios of 18.23–18.27) in the Dalucao calcites refute the hypothesis of crustal assimilation as their genetic source. Instead, the radiogenic Sr isotopic compositions suggest that subducted marine sediments have contaminated the lithospheric mantle that generated the carbonatitic magma. Mineralogical evidence indicating the presence of abundant silicate minerals in the Dalucao carbonatites, combined with a compilation of published C-O isotopic data, suggests that these carbonatites may have resulted from low-degree partial melting (melting proportion

This paper presents the stability analysis of a class of second-order linear partial differential equations (PDEs) on time scales with diffusion operator and first-order partial derivative. According to the time scale theory, the Lyapunov functional method, and some inequality techniques, sufficient conditions for exponential stability are strictly obtained, and the results are generalized for that where both the discrete-time and continuous-time cases are considered jointly. In addition, the theoretical results are applied to exponential synchronization of reaction-diffusion neural networks (RDNNs). Simulation examples are given to verify the feasibility of our results.

The water quality of the Golmud River is essential for environmental preservation and economic growth of Golmud city and Qarhan Salt Lake in China. Thirty-four samples of surface water and sediment from seventeen places in the Golmud River and thirty-two dustfall samples in the Qaidam Basin were collected. The concentrations of heavy metals (HMs) were measured; water quality, risk assessment, and multiple source analysis were applied. Concentrations of HMs in water were Zn > Cu > Ni > As > Pb > Cd > Hg, and in sediment were Ni > Zn > Pb > As > Cu > Cd > Hg. In water, the Nemerow pollution index (NP) values indicated that most of the sampling points seemly were seriously polluted; other water quality assessment results suggested no pollution. In sediment, the concentrations of 27% HMs exceeded the background values of soil in Qinghai; 48% exceeded the Earth crust background values, which were As, Hg, and Cd. The single factor index method (Pi), geological accumulation index (Igeo), and contamination factor (CF) revealed that As pollution is serious, followed by Hg and Cd; the pollution load index (PLI) and modified pollution index (mCd) values indicated that 64% and 57% of samples were polluted. NP values are shown serious pollution. The ecological risk results demonstrated a low risk in water and a medium risk in sediment. The average total hazard quotient values in sediment and water for adults and children revealed low non-carcinogenic risks. Carcinogenic risk indicated Ni in water and sediment, and As in sediment may be involved in cancer risk. Multivariate statistics showed that the HMs mainly came from nature, and human activities will also impact them. The upper continental crust values indicated that As and Hg have high background values. The saline dust storm was one of the essential sources of HMs, especially Hg. Various provenances constituted the material cycling of HMs in the surface environment.

Abstract Our objective in this paper is to study the oscillatory and asymptotic behavior of the solutions of third-order neutral differential equations with damping and distributed deviating arguments. New oscillation criteria are established, which are based on a refinement generalized Riccati transformation. An important tool for this investigation is the integral averaging technique. Moreover, we provide an example to illustrate the main results.

Summary: Endoplasmic reticulum (ER) homeostasis is essential for plants to manage responses under environmental stress. Plant immune activation requires the ER, but how ER homeostasis is associated with plant immune activation is largely unexplored. Here we find that transcription of an HVA22 family gene, OsHLP1 (HVA22-like protein 1), is induced by Magnaporthe oryzae infection. Overexpression of OsHLP1 significantly enhances blast disease resistance but impairs ER morphology in rice (Oryza sativa), resulting in enhanced sensitivity to ER stress. OsHLP1 interacts with the NAC (NAM, ATAF, and CUC) transcription factor OsNTL6 at the ER. OsNTL6 localizes to the ER and is relocated to the nucleus after cleavage of the transmembrane domain. OsHLP1 suppresses OsNTL6 protein accumulation, whereas OsNTL6 counteracts OsHLP1 by alleviating sensitivity to ER stress and decreasing disease resistance in OsHLP1 overexpression plants. These findings unravel a mechanism whereby OsHLP1 promotes disease resistance by compromising ER homeostasis when plants are infected by pathogens.

Abstract Epilepsy is a chronic neurological disorder that has an extensive impact on a patient’s life. Accumulating evidence has suggested that inflammation participates in the progression of spontaneous and recurrent seizures. Pro-convulsant incidences can stimulate immune cells, augment the release of pro-inflammatory cytokines, elicit neuronal excitation as well as blood-brain barrier (BBB) dysfunction, and finally trigger the generation or recurrence of seizures. Understanding the pathogenic roles of inflammatory mediators, including inflammatory cytokines, cells, and BBB, in epileptogenesis will be beneficial for the treatment of epilepsy. In this systematic review, we performed a literature search on the PubMed database using the following keywords: “epilepsy” or “seizures” or “epileptogenesis”, and “immunity” or “inflammation” or “neuroinflammation” or “damage-associated molecular patterns” or “cytokines” or “chemokines” or “adhesion molecules” or “microglia” or “astrocyte” or “blood-brain barrier”. We summarized the classic inflammatory mediators and their pathogenic effects in the pathogenesis of epilepsy, based on the most recent findings from both human and animal model studies.

Abstract The liver is a unique organ that has a phenomenal capacity to regenerate after injury. Different surgical procedures, including partial hepatectomy (PH), intraoperative portal vein ligation (PVL), and associated liver partition and portal vein ligation for staged hepatectomy (ALPPS) show clinically distinct recovery patterns and regeneration. The observable clinical differences likely mirror some underlying variations in the patterns of gene activation and regeneration pathways. In this study, we provided a comprehensive comparative transcriptomic analysis of gene regulation in regenerating rat livers temporally spaced at 24 h and 96 h after PH, PVL, and ALPPS. The time-dependent factors appear to be the most important determinant of post-injury alterations of gene expression in liver regeneration. Gene expression profile after ALPPS showed more similar expression pattern to the PH than the PVL at the early phase of the regeneration. Early transcriptomic changes and predicted upstream regulators that were found in all three procedures included cell cycle associated genes (E2F1, CCND1, FOXM1, TP53, and RB1), transcription factors (Myc, E2F1, TBX2, FOXM1), DNA replication regulators (CDKN1A, EZH2, RRM2), G1/S-transition regulators (CCNB1, CCND1, RABL6), cytokines and growth factors (CSF2, IL-6, TNF, HGF, VEGF, and EGF), ATM and p53 signaling pathways. The functional pathway, upstream, and network analyses revealed both unique and overlapping molecular mechanisms and pathways for each surgical procedure. Identification of molecular signatures and regenerative signaling pathways for each surgical procedure further our understanding of key regulators of liver regeneration as well as patient populations that are likely to benefit from each procedure.

This paper analyzes the input-to-state stability (ISS) properties of subhomogeneous cooperative systems for the first time. A new definition of finite-time ISS (FISS) for nonlinear positive systems is given. For stability analysis, the max-separable Lyapunov function is used, and the min-separable Lyapunov-like function is presented for the first time in this paper. Using these functions, we obtain our main results on solution estimates for subhomogeneous positive systems. According to the proposed method of analysis, the ISS properties of these systems can be easily judged only on the basis of their differential and algebraic characteristics. Simulation examples verify the validity of our results.

Winding system is a production system commonly used in industry. Its control goal is to achieve constant tension control of the system by controlling motor torque, and to cope with various external disturbances in industrial environment. The Fractional Order PID (FOPID) controller is well known for its simplicity with better tuning flexibility as well as robustness with respect to disturbances. Thus, this paper proposes a control strategy based on FOPID to achieve the control objectives. First, a linear approximation model is established for the constant tension control system. Then, a FOPID controller is designed based on the model. Four non-linear constraints and an objective function of the controller are proposed based on the frequency domain. Five tunable parameters of FOPID are determined by combining genetic algorithm (GA) with FMINCON non-linear optimization. Finally, through the simulation of MATLAB, the performance of the controller is compared with the classic integer order PID. The results show that the FOPID controller has better control characteristics and robustness.

We present a sum of squares (SOS) method for the synthesis of nonlinear polynomial control systems. As an emerging numerical solution method in recent years, SOS targets polynomials as the research object. It guarantees that the polynomial we solve for is always nonnegative. In this paper, we give a generalized S-procedure to solve the SOS problem. As an illustration of how the SOS method can be used, the region of attraction (ROA) in a nonlinear polynomial system is analyzed in detail. The method of determining decision variables is given in the SOS problem. We discuss the determination and solution of set-containment constraints and the conservatism problem in solving the SOS problem. SOS provides a convenient numerical method to solve nonlinear problems that are not easy to solve analytically.

The control aim of parabolic distributed solar collector (PDSC) is to make the heat generated follow the expected reference value when the solar radiation varies unevenly. This article proposes a control strategy based on fractional-order PID (FOPID) to achieve control objectives. Four non-linear constraints and an objective function of the controller are proposed based on the frequency domain. Most studies regard the constraint measuring stability as the objective function, while the real difficulty for the control system design should be how to obtain better robustness. Therefore, this article determines five parameters of FOPID by selecting the constraint measuring robustness as the objective function based on Particle swarm optimization (PSO). Besides, three non-parametric statistical tests, including Friedman ranks, Friedman Aligned ranks and Quade ranks, have been adopted to compare PSO with other evolutionary algorithms to demonstrate its advantage. Finally, the superiority of proposed strategy to previous design is demonstrated by the simulation studies on a PDSC in terms of the control performance of step response, static gain variation, time constant variation, high frequency noise and output interference.

This paper provides an in-depth discussion of human motion recognition in Virtual Reality (VR) video sequences through hidden Markov models, which are four steps from VR video acquisition and pre-processing, foreground detection, extraction of human feature parameters, and hidden Markov model human motion recognition. A hybrid Gaussian model was used to build a background model in real-time based on changes in VR video information, and the image was subtracted by the background differential method. The optical flow method was used for foreground detection of the target, and the effects of sparse and dense optical flow were compared to obtain the motion characteristics and optical flow information of the target human body, respectively. Features were extracted for human motion, in terms of common geometric features of the body and optical flow information, respectively. In terms of common geometric information, the width-to-height ratio, perimeter-to-area ratio, center of mass, eccentricity, and feature angle were extracted, respectively. For the optical flow information, optical flow descriptors were constructed using a grid-based approach. And feature fusion was performed for the above two parameters by the k-means method to construct the word pocket model. The hidden Markov model parameters were obtained by using the hidden Markov model for the recognition of human motion and training the human feature parameters for each of the four motions. The recognition of the four common human body movements was realized by the forward-backward algorithm. The test results show that the motion recognition method in this paper has high recognition performance and good anti-interference performance. The time-sequence pooling is used to sort the effective video frame feature sequences to obtain the feature vectors that can represent the dynamic changes of video time sequence; finally, the time-sequence feature vectors are used to train the support vector machine for classification recognition. The recognition accuracy is 65.2% and 89.4% for the HMDB51 and UCF101 datasets, respectively.

This paper focuses on the tracking control problem of Magnetic Levitation System (MLS). MLS is highly unstable nonlinear system, in the process of operation, MLS needs to have strong robustness and anti-interference ability. Due to disturbance and parameter uncertainties in MLS, it is complex to obtain the exact dynamics of MLS, and it is difficult to design a suitable controller. The dynamic equation of the system is established by Lagrange equation, and then we propose an adaptive Sliding Mode Control (SMC) based on Radial Basis Function Neural Network (RBFNN). Because of the parameter uncertainties and disturbance in MLS, RBFNN is used to approximate the unknown dynamics in MLS. The stability of the closed-loop system is strictly proved by using the Lyapunov stability theory, which can achieve the uniform ultimate boundedness (UUB) of the signals of the closed-loop MLS. MATLAB environment is used to verify the performance of the proposed controller. Considering disturbance, parameter change, or unmodeled dynamics in MLS, proposed controller is compared with other nonlinear controllers, simulation results verify the effectiveness of the proposed approach.

BackgroundTumor necrosis factor-stimulated gene-6 (TSG-6) is a multifunctional, anti-inflammatory, and protective protein, while the association between TSG-6 and acute ischemic stroke (AIS) remains unclear in humans. This study aims to investigate the potential diagnostic and short-term prognosis predictive values of TSG-6 in non-cardioembolic AIS.MethodsA total of 134 non-cardioembolic AIS patients within 24 h after AIS onset and 40 control subjects were recruited. Using an AIS dataset from the Gene Expression Omnibus database and setting the median expression level of TNFAIP6 as the cutoff point, data were divided into TNFAIP6-high and TNFAIP6-low expression groups. Differently expressed genes (DEGs) were extracted to perform gene enrichment analysis and protein–protein interaction (PPI) network. Baseline data were analyzed in a four-group comparison plotted as plasma TSG-6 concentration median and 25th/75th percentiles. The correlative factors of 3-month outcome were evaluated by logistic regression. TSG-6 concentrations and TSG-6-to-interleukin-8 ratios were compared in a block design. A receiver-operating characteristic curve was used to analyze the detective value of TSG-6 and 3-month prognosis predictive values of TSG-6 and TSG-6-to-interleukin-8 ratio.ResultsNon-cardioembolic AIS patients had significantly higher plasma TSG-6 levels than control subjects (P

With the rapid development of social economy and modern industry, the performance requirements of some important nanomaterials in various fields are constantly improving. The processing of these nanomaterials will have a direct impact on the development level of some core industries, such as aerospace, medical devices, and automobile manufacturing. In the early stage of the machining process, the BP neural network is generally used to control the CNC machining. However, it also has some shortcomings, such as the inability to determine the initial parameter weights according to the errors in the processing process, which limits its application in processing control. Therefore, this paper used RBF neural network to solve the problems in the process of CNC machining of nanomaterials and, at the same time, integrated RBF neural network technology into CNC electronic machining control, so as to improve the precision of CNC electronic machining of nanomaterials and avoid the occurrence of errors to the greatest extent. The method proposed in this paper used the self-learning and self-adaptive ability of RBF neural network to adjust the parameters of CNC machining control and relied on its fast convergence speed and strong approximation ability to achieve better CNC machining control effect. The experimental results showed that, after integrating the control technology of RBFNN in the CNC machining process of nanomaterials, the roundness error and roughness error of the machined workpiece were reduced by 70% and 50%, respectively. The control method proposed in this paper has high precision and strong stability.

This paper studies the intra/inter-layer synchronization and quasi-synchronization in two-layer coupled networks via event-triggered control, in which different layers have mutually independent topologies. First, based on Lyapunov stability theory and event-triggered thoughts, hybrid controllers are designed, respectively, for intra-layer synchronization (ALS) and inter-layer synchronization (RLS). Second, a novel event-triggered rule is proposed, under which intra-layer quasi-synchronization (ALQS) and inter-layer quasi-synchronization (RLQS) can be respectively realized, and the event-triggered frequency can be greatly reduced. Moreover, the upper bound of the synchronization error can be flexibly adjusted by changing the parameters in event-triggered conditions, and the Zeno phenomenon about event-triggered control is also discussed in this paper. Finally, numerical examples are provided to confirm the correctness and validity of the proposed scheme.

Polyhalite occurrence in the Kunteyi Playa in the Qaidam Basin has been known for many years. However, the genetic mechanism of this deposit remains unclear. In this study, a typical section in the playa depocenter is selected to study the polyhalite mineralogy combined with the homogenization temperature and composition of halite fluid inclusions in shallow evaporitic strata. The results show that 1) the main evaporite minerals in the strata are halite and polyhalite; no common gypsum is found; 2) analyses of homogenization temperatures of halite fluid inclusions indicate that a higher temperature is needed for polyhalite generation compared with other saline minerals; and 3) the fluid inclusion chemical analysis shows that they are sulfate-type minerals with a shortage of Ca. Thus, it can be concluded that the formation of polyhalite is not related to gypsum replacement, and deep oilfield brines may provide a Ca source and a higher temperature for polyhalite formation, where the mixing and interaction occurred between K- and Mg-enriched sulfate brines and deep Ca-enriched brines under the control of climate and tectonics in the study area. While most polyhalite was generated natively, some formed during secondary generation, which was potentially related to replacement with carnallites or sylvites.

Abstract Some new nonlinear weakly singular integral inequalities of Gronwall–Bellman–Pachpatte type are given. The estimations of unknown functions are obtained by analysis techniques. These estimates are very significant tools in the study of differential-integral equations.

Abstract In this article, we regard the generalized Riccati transformation and Riemann–Liouville fractional derivatives as the principal instrument. In the proof, we take advantage of the fractional derivatives technique with the addition of interval segmentation techniques, which enlarge the manners to demonstrate the sufficient conditions for oscillation criteria of certain fractional partial differential equations.

Abstract Traditional simulation methods are unable to meet the requirements of lunar takeoff simulations, such as high force output precision, low cost, and repeated use. Considering that cable-driven parallel mechanisms have the advantages of high payload to weight ratio, potentially large workspace, and high-speed motion, these mechanisms have the potential to be used for lunar takeoff simulations. Thus, this paper presents a parallel mechanism driven by nine cables. The purpose of this study is to optimize the dimensions of the cable-driven parallel mechanism to meet dynamic workspace requirements under cable tension constraints. The dynamic workspace requirements are derived from the kinematical function requests of the lunar takeoff simulation equipment. Experimental design and response surface methods are adopted for building the surrogate mathematical model linking the optimal variables and the optimization indices. A set of dimensional parameters are determined by analyzing the surrogate mathematical model. The volume of the dynamic workspace increased by 46% after optimization. Besides, a force control method is proposed for calculating output vector and sinusoidal forces. A force control loop is introduced into the traditional position control loop to adjust the cable force precisely, while controlling the cable length. The effectiveness of the proposed control method is verified through experiments. A 5% vector output accuracy and 12 Hz undulation force output can be realized. This paper proposes a cable-driven parallel mechanism which can be used for lunar takeoff simulation.

Abstract Electric energy is an indispensable energy in life, and the power network is the basis to ensure its normal circulation, in which the operation status of power equipment is one of the key factors to determine the safe and stable operation of the power network. In the information age, the traditional manual periodic inspection and the existing method of relying on manual monitoring equipment operation status can no longer meet the needs of safe operation of equipment; relying on computer technology and image recognition technology to achieve automatic identification of power equipment has become a research hot spot. In order to realize automatic identification of power equipment, this paper presents a method of recognition of power equipment based on image processing. Firstly, the power equipment image is preprocessed by various denoising and sharpening algorithms to remove the noise and distortion of the image and improve the image quality; secondly, the SIFT algorithm is used to extract image features, and PCA algorithm is used to reduce the dimension; finally, the support vector machine is used to classify and recognize the image. The simulation results show that the proposed denoising and sharpening algorithms can process images well and improve the quality of images. The support vector machine is used to classify the image features processed by SIFT algorithm and PCA algorithm, and the automatic recognition of power equipment is realized. And the method of power identification based on image processing proposed in this paper has good recognition accuracy.

This paper studies the problem of disturbance attenuation and rejection for switched systems with nonlinear uncertainty and input saturation via composite anti-disturbance control technique, in which the exosystem-generated disturbance and H2-norm-bounded disturbance are considered. For switched systems, the switching law and input saturation increase the difficulty for the design of the disturbance observer and the composite control scheme. A switching disturbance observer is designed to obtain the estimation of the matched disturbance, and a novel switching composite controller is further constructed based on the estimated value. By proposing a state-dependent switching law and utilizing the multiple Lyapunov function technology, the criteria are presented to ensure the local asymptotic stability with an H∞ performance level for the closed-loop system. Furthermore, two optimal algorithms of the design of the controller are put forward to maximize the estimation of the domain of attraction of the closed-loop and the upper bound on the H2-norm of the disturbance, respectively. The effectiveness of the proposed technique is illustrated via the numerical examples.

Abstract This paper investigates a class of nonlinear dynamic integral inequalities with mixed nonlinearities in two independent variables. The obtained results can be utilized to study the boundedness of partial dynamic systems on time scales. At the end, an example is presented to illustrate the main results.

Reef-building corals are ecosystem engineers that compete with other benthic organisms for space and resources. Corals harvest energy through their surface by photosynthesis and heterotrophic feeding, and they divert part of this energy to defend their outer colony perimeter against competitors. Here, we hypothesized that corals with a larger space-filling surface and smaller perimeters increase energy gain while reducing the exposure to competitors. This predicted an association between these two geometric properties of corals and the competitive outcome against other benthic organisms. To test the prediction, fifty coral colonies from the Caribbean island of Curaçao were rendered using digital 3D and 2D reconstructions. The surface areas, perimeters, box-counting dimensions (as a proxy of surface and perimeter space-filling), and other geometric properties were extracted and analyzed with respect to the percentage of the perimeter losing or winning against competitors based on the coral tissue apparent growth or damage. The increase in surface space-filling dimension was the only significant single indicator of coral winning outcomes, but the combination of surface space-filling dimension with perimeter length increased the statistical prediction of coral competition outcomes. Corals with larger surface space-filling dimensions (Ds > 2) and smaller perimeters displayed more winning outcomes, confirming the initial hypothesis. We propose that the space-filling property of coral surfaces complemented with other proxies of coral competitiveness, such as life history traits, will provide a more accurate quantitative characterization of coral competition outcomes on coral reefs. This framework also applies to other organisms or ecological systems that rely on complex surfaces to obtain energy for competition.

User location prediction in location-based social networks can predict the density of people flow well in terms of intelligent transportation, which can make corresponding adjustments in time to make traffic smooth, reduce fuel consumption, reduce greenhouse gas emissions, and help build a green cycle low-carbon transportation green system. This paper proposes a Markov chain position prediction model based on multidimensional correction (MDC-MCM). Firstly, extract corresponding information from the user’s historical check-in position sequence as a position-position conversion map. Secondly, the influence of check-in period, space distance, and other factors on the position prediction is linearly weighted and merged with the position prediction of the n-order Markov chain to construct MDC-MCM. Finally, we conduct a comprehensive performance evaluation of MDC-MCM using the dataset collected from Brightkite. Experimental results show that compared with other advanced location prediction technologies, MDC-MCM achieves better location prediction results.

Flexible solar panels play an essential role in the field of aerospace. However, many difficulties appear in the control design due to the existence of a weakly damped resonance module. The design for flexible systems often causes an unstable controller so that the systems after design still have trouble in putting into practice. We adopt H∞ loop-shaping design and put forward a directive method for selecting the weighting function. The simulation results indicate that system bandwidth is optimized based on the stable controller. In this way, the control precision and response speed of the system are improved. In the meantime, the system is easy to put into use.

This paper proposes an H∞ observer based on descriptor systems to estimate the state of charge (SOC). The battery’s open-current voltage is chosen as a generalized state variable, thereby avoiding the artificial derivative calculation of the algebraic equation for the SOC. Furthermore, the observer’s dynamic performance is saved. To decrease the impacts of the uncertain noise and parameter perturbations, nonlinear H∞ theory is implemented to design the observer. The sufficient conditions for the H∞ observer to guarantee the disturbance suppression performance index are given and proved by the Lyapunov stability theory. This paper systematically gives the design steps of battery SOC H∞ observers. The simulation results highlight the accuracy, transient performance, and robustness of the presented method.

Abstract In this paper, we investigate oscillatory and asymptotic properties for a class of fractional order dynamic equations on time scales, where the fractional derivative is defined in the sense of the conformable fractional derivative. Based on the properties of conformable fractional differential and integral, some new oscillatory and asymptotic criteria are established. Applications of the established results show that they can be used to research oscillation for fractional order equations in various time scales such as fractional order differential equations, fractional order difference equations, and so on.

In this paper, the Ulam stability of an n-th order delay integro-differential equation is given. Firstly, the existence and uniqueness theorem of a solution for the delay integro-differential equation is obtained using a Lipschitz condition and the Banach contraction principle. Then, the expression of the solution for delay integro-differential equation is derived by mathematical induction. On this basis, we obtain the Ulam stability of the delay integro-differential equation via Gronwall–Bellman inequality. Finally, two examples of delay integro-differential equations are given to explain our main results.

As a heavy metal, Pb is one component in coal-fired flue gas and is widely considered to have a strong negative effect on catalyst activity in the selective catalytic reduction of NOx by NH3 (NH3-SCR). In this paper, we investigated the deactivation mechanism of the Mo-Ce/Zr-PILC catalyst induced by Pb in detail. We found that NO conversion over the 3Mo4Ce/Zr-PILC catalyst decreased greatly after the addition of Pb. The more severe deactivation induced by Pb was attributed to low surface area, lower amounts of chemisorbed oxygen species and surface Ce3+, and lower redox ability and surface acidity (especially a low number of Brønsted acid sites). Furthermore, the addition of Pb inhibited the formation of highly active intermediate nitrate species generated on the surface of the catalyst, hence decreasing the NH3-SCR activity.

The coupling between variables in the multi-input multi-output (MIMO) systems brings difficulties to the design of the controller. Aiming at this problem, this paper combines the particle swarm optimization (PSO) with the coefficient diagram method (CDM) and proposes a robust controller design strategy for the MIMO systems. The decoupling problem is transformed into a compensator parameter optimization problem, and PSO optimizes the compensator parameters to reduce the coupling effect in the MIMO systems. For the MIMO system with measurement noise, the effectiveness of CDM in processing measurement noise is analyzed. This paper gives the control design steps of the MIMO systems. Finally, simulation experiments of four typical MIMO systems demonstrate the effectiveness of the proposed method.

Abstract In this paper, some explicit bounds on solutions to a class of new power nonlinear Volterra-Fredholm type dynamic integral inequalities on time scales are established, which can be used as effective tools in the study of certain dynamic equations. Application examples are also given.

The Hamilton–Jacobi–Issacs (HJI) inequality is the most basic relation in nonlinear H∞ design, to which no effective analytical solution is currently available. The sum of squares (SOS) method can numerically solve nonlinear problems that are not easy to solve analytically, but it still cannot solve HJI inequalities directly. In this paper, an HJI inequality suitable for SOS is firstly derived to solve the problem of nonconvex optimization. Then, the problems of SOS in nonlinear H∞ design are analyzed in detail. Finally, a two-step iterative design method for solving nonlinear H∞ control is presented. The first step is to design an adjustable nonlinear state feedback of the gain array of the system using SOS. The second step is to solve the L2 gain of the system; the optimization problem is solved by a graphical analytical method. In the iterative design, a diagonally dominant design idea is proposed to reduce the numerical error of SOS. The nonlinear H∞ control design of a polynomial system for large satellite attitude maneuvers is taken as our example. Simulation results show that the SOS method is comparable to the LMI method used for linear systems, and it is expected to find a broad range of applications in the analysis and design of nonlinear systems.

This paper focuses on the problem of state estimation for certain switched time-varying systems with time-varying delay and nonlinear disturbance. By using an integral inequality technique and a method used in positive systems, we have established several explicit criteria for state estimation of the system, which reduce to stability criteria for some particular cases. The involved nonlinear disturbance of the system takes more general form including both the internal disturbance and the external disturbance. Three numerical examples are also given to verify the validity of the obtained theoretical results.

Abstract In this paper, we present some new Volterra-Fredholm-type discrete fractional sum inequalities. These inequalities can be used as handy and powerful tools in the study of certain fractional sum-difference equations. Some applications are also presented to illustrate the usefulness of our results.

Abstract Some new inequalities with weakly singular integral kernel are developed, which generalize some known inequalities and can be used in the qualitative and quantitative analysis of the solutions to certain fractional differential equations.

In this paper, we focus on the second-order neutral differential equations with deviating arguments which are under the canonical condition. New oscillation criteria are established, which are based on a first-order delay differential equation and generalized Riccati transformations. The idea of symmetry is a useful tool, not only guiding us in the right way to study this function but also simplifies our proof. Our results are generalizations of some previous results and we provide an example to illustrate the main results.

This paper presents a supervised Hebb learning single neuron adaptive proportional-integral-derivative (PID) controller for the power control of a cold milling machine. The proposed controller aims to overcome the deficiency of the current power control algorithm, and to achieve as high an output power as possible for the cold milling machine. The control process and system model are established and presented to provide the insight and guidance to the controller design and analysis. The adaptive PID controller is developed using a supervised Hebb learning single neuron method with detailed algorithm and structure analysis. The field test is performed to validate the proposed single neuron adaptive PID control for the power control. In the test, the 8 cm-depth milling is conducted on a cement concrete pavement in which the cement is not well-distributed. The test results show that when the machine speed is adjusted by the machine itself or manually without the adaptive power control system, the machine is often overloaded or underloaded, and the average work speed is 2.4m/min. However, when the adaptive control system is implemented on the machine, it works very close to its rated work condition during its work process. With the developed controller, the machine work speed is adjusted in time to the load variation and uncertain dynamics. The average machine work speed can reach up to 2.766 m/min, which is 15.25% higher than the wok speed of the machine without an adaptive power control system.

The passivity-based control (PBC) is a new direction of nonlinear control, but the method is basically a qualitative method. A quantifiable design method in combination with PBC is provided in this paper. To solve the partial differential equation (PDE) for PBC, the nonlinear system must first be transformed into a Hamiltonian model. The PDE for the Hamiltonian system is then quantifiably solved with an electromagnetic levitation example. The resulting control law is presented and discussed. The proposed method provides a practical design tool for nonlinear control.

In this article, the mechanical properties of large-scale rack structures are analysed by MSC Marc analysis software is verified through the modal test. The modal frequency and modal shape are obtained through the finite element analysis and LMS data acquisition system for modal test verification. It is showed that the modal shape of the modal test and the calculation by finite element analysis are consistent, which verifies the inherent characteristics of the frame structure effectively and provides reliability parameters of the manipulator for the space station in the zero-gravity test.

We investigate the problem of reachable set bounding for a class of continuous-time and discrete-time nonlinear time-varying systems with time-varying delay. Unlike some preceding works, the involved disturbance input and time-varying delay are not assumed to be bounded. By employing an approach which does not involve the conventional Lyapunov-Krasovskii functional, new conditions are proposed such that all the state trajectories of the system converge asymptotically within a ball. Two illustrative examples are also given to show the effectiveness of the obtained results.

In this paper, an auxiliary equation method is introduced for seeking exact solutions expressed in variable coefficient function forms for fractional partial differential equations, where the concerned fractional derivative is defined by the conformable fractional derivative. By the use of certain fractional transformation, the fractional derivative in the equations can be converted into integer order case with respect to a new variable. As for applications, we apply this method to the time fractional two-dimensional Boussinesq equation and the space-time fractional (2+1)-dimensional breaking soliton equation. As a result, some exact solutions including variable coefficient function solutions as well as solitary wave solutions for the two equations are found.

Lyapunov functions play a key role in the stability analysis of complex systems. In this paper, we study the existence of a class of common weak linear copositive Lyapunov functions (CWCLFs) for positive switched linear systems (PSLSs) which generalize the conventional common linear copositive Lyapunov functions (CLCLFs) and can be used as handy tool to deal with the stability of PSLSs not covered by CLCLFs. We not only establish necessary and sufficient conditions for the existence of CWCLFs but also clearly describe the algebraic structure of all CWCLFs. Numerical examples are also given to demonstrate the effectiveness of the obtained results.

This paper presents the robust stability analysis based on LMI for force feedback haptic interface systems with uncertain delay. A full-order state observer is introduced to estimate states of the haptic device so as to directly obtain the feedback force, which expands the stability range of the system environment parameters when comparing with that of the system without an observer. By using the delay partitioning idea and the augmented state vector, the Lyapunov-Krasovskii functional is constructed, and then the new stability criterion based on LMI is given in the paper. With this new stability criterion, the observer gains can also be obtained directly. At last, a concrete example is used to prove the effectiveness and less conservativeness of this new approach.