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Summary: Variable‐pitch quadrotors have demonstrated their capability to enhance control performance and overcome limitations compared to conventional fixed‐pitch quadrotors, while still facing challenges such as nonlinearity, couplings, uncertainties and so on. This article aims to address the robust attitude control problem of variable‐pitch quadrotors afflicted with parametric uncertainties and unpredictable external disturbances. Initially, a practical actuator allocation strategy for the motor‐propeller is proposed, followed by the development of a nonlinear robust attitude tracking controller capable of addressing all uncertainties. The effectiveness of the proposed controller in ensuring exponential stability of the closed‐loop system, thereby driving the attitude tracking error to a small range within a finite time, has been substantiated. To evaluate the control performance, a hardware‐in‐the‐loop testbed is constructed to conduct real‐time experiments. The experimental results from attitude control case, comparative case, and position control case demonstrate that the designed motor‐propeller allocation method and robust controller are effective in achieving a fast response and excellent control performance. [ABSTRACT FROM AUTHOR]

During reentry, the high temperatures experienced by near-space hypersonic vehicles result in surface ablation, generating ablative particles. These particles become part of a plasma, commonly referred to as a "dusty plasma sheath" in radar remote sensing. The dusty plasma model, integral in radar studies, involves extensive charge and dynamic interactions among dust particles. Previous derivations assumed that the dust particle radius significantly surpassed the Debye radius, leading to the neglect of dust radius effects. This study, however, explores scenarios where the dust particle radius is not markedly smaller than the Debye radius, thereby deducing the charging process of dusty plasma. The derived equations encompass the Debye radius, charging process, surface potential, and charging frequency, particularly considering larger dust particle radii. Comparative analysis of the dusty plasma model, both before and after modification, reveals improvements when dust particles approach or exceed the Debye length. In essence, our study provides essential equations for understanding dusty plasma under realistic conditions, offering potential advancements in predicting electromagnetic properties and behaviors, especially in scenarios where dust particles closely align with or surpass the Debye radius. [ABSTRACT FROM AUTHOR]

The interaction mechanism between plasmas and electromagnetic waves has not been fully defined, and experiments are helpful for investigating the mechanism and verifying the theoretical analysis. This paper proposes a point-focusing lens antenna based on three-dimensional (3D) printing technology for the experimental study of the interaction between electromagnetic waves and a small-area plasma. First, CST simulation software was used for the simulation design of the horn antenna and focusing lens. Subsequently, 3D printing technology was used to print the lens combined with the horn antenna for experimental verification of the focusing performance. Finally, an electromagnetic wave passing through a plasma was experimentally investigated, and it was mutually verified with the propagation theory of electromagnetic waves in plasmas. The experimental and theoretical data indicated that the 3D-printed point-focusing lens antenna exhibited a good focusing effect on electromagnetic waves. This method may be used by employing a variety of materials and designs, thereby considerably improving the detection of small-area plasma. It may also solve the issue of the radial diffraction effect of narrow cylindrical plasma generated by inductively coupled plasma-generation equipment and reduce the error associated with experimental data. Therefore, this method may be useful for plasma propagation measurement, plasma-environment diffraction analysis, and parameter inversion of complex plasma environments. [ABSTRACT FROM AUTHOR]

The breakthrough of energy storage technology will enable energy distribution and adaptation across space‐time, which is revolutionary for the generation of energy. Optimizing the energy storage performance of polymer dielectrics remains challenging via the physical process of electrical breakdown in solid dielectrics is hard to be intuitively obtained. In this review article, the application of computational simulation technologies is summarized in energy‐storage polymer dielectrics and the effect of control variables and design structures on the material properties with an emphasis on dielectric breakdown and energy storage performance are highlighted. The prediction and evaluation of material properties by combining various data analysis methods are reviewed. Finally, the outlook and challenges are discussed based on their current developments. This article covers not only an overview of the state‐of‐the‐art advances of breakdown modeling in energy‐storage polymer dielectrics but also the prospects that provide a new knob to synthesize high energy‐storage polymer dielectrics via computational simulation and a new research paradigm. [ABSTRACT FROM AUTHOR]

Most individuals are willing to purchase suitable sporting goods and/or services to support physical health management (PHM). PHM-oriented research of sports consumption behavior (SCB) aids in objectively grasping and understanding the impact of PHM demand and awareness on SCB and in providing consumers with products/services through scientific marketing. Existing research lacks appropriate methods for clustering high-dimensional data on sports consumption and ignores the continuity of PHM and the time aspect of key consumption behaviors. This study investigates the PHM-oriented SCB and analyses the appropriate marketing tactics to address the issues. First, the authors presented the flowchart for the associated data analysis on PHM-oriented sports consumption and clustered the multivariate sports consumption data. Next, a method for fine-grained correlation analysis was outlined for sports consumption data, and an algorithm for selecting the ideal results of canonical correlation analysis (CCA) with kernels was provided. Finally, the proposed algorithm's complexity was evaluated. The authors analyzed the relationships between PHM demand and attitude and SCB, developed differential analysis results, and evaluated marketing methods. [ABSTRACT FROM AUTHOR]

Relaxed fault estimation (FE) criteria of a class of discrete-time nonlinear plants are proposed based on a new multi-instant real-time scheduling fuzzy FE observer. Compared with the existing methods given in the recent literature, the newly developed fuzzy observer is capable of providing much freedom for reducing the conservatism of designing feasible FE criteria. At each sampling point, the information of adjacent groups of normalized fuzzy weighting functions can be updated and utilized for deciding the activated mode of our developed fuzzy FE observer. Based on this, an exclusive pair of gain matrices can be given by introducing a set of well-designed free matrices into the designed FE criteria for every activated mode. Moreover, it can be found that the proposed result will include the previous one as a special case if all of those free matrices are removed. Finally, the well-known nonlinear truck–trailer plant with actuator fault is utilized to validate the superiority of our approach over the existing ones reported in the literature. [ABSTRACT FROM AUTHOR]

In order to study the influence of harmonics on the vibration and noise of permanent magnet synchronous motor, this paper introduces an analysis method based on field-circuit coupling, and establishes a complete analysis process from the control strategy to the vibration and noise response of the motor. Firstly, the coupling model including control strategy, main circuit model and electromagnetic field model is established. Secondly, the finite element model of the permanent magnet synchronous motor under the influence of coupling is established to analyze and compare the electromagnetic force wave characteristics of the coupling excitation and the sinusoidal excitation. Then, the coupled electromagnetic force is loaded into the structural field to simulate and calculate the vibration and noise. Finally, the effectiveness of the model is verified through experimental sound pressure level comparison under steady-state and speed-up conditions, and it provides a reference for vibration and noise prediction of the motor system. [ABSTRACT FROM AUTHOR]

Dusty plasma environments, such as aircraft sheaths and rocket exhaust plumes, significantly affect the propagation of electromagnetic (EM) waves. In this study, the Mie theory and the dyadic Green method were used to calculate the Mie scattering cross section, Debye scattering cross section of the surrounding Debye cloud, and Mie–Debye coherence cross section formed by the two scattering fields. We propose that the Mie–Debye model should be regarded as a whole particle, and the dusty plasma can be simplified by assuming that it is composed of Mie–Debye spherical models of different densities. These assumptions were combined with the scattering characteristics of the microscopic Mie–Debye model and Monte Carlo method to analyze the propagation characteristics of EM waves in dusty plasma. [ABSTRACT FROM AUTHOR]

• 12 AtVAMPs and 24 PbrVAMPs were identified from Arabidopsis and pear genomes, respectively. • WGD (whole genome duplication) and purification selection play vital roles during the evolution of the VAMP gene family. • PbrVAMP721i was highly expressed in pollen tube and positively regulates pear pollen tube growth. • PbrVAMP721i positively regulates the transport of vesicles at the pollen tube apex. An important factor in completing double fertilization is the rapid growth of the pollen tube in the transmitting tissue to the ovary. During this process, the normal transport of vesicles at the apex of the pollen tube is the key to the rapid extension of pollen tube. Vesicular Associated Membrane Proteins (VAMPs), play a crucial role in mediating membrane fusion. Nonetheless, the function of VAMP in the growth of pear pollen tubes remains unclear. Here, we successfully identified and categorized 24 VAMP genes, sourced from the pear genome, into six distinct clades. Evolutionary analysis showed that whole genome duplication (WGD) was dominant in the expansion of the pear VAMP gene family. Meanwhile, it was discovered that purification selection plays an integral part in the evolution of the VAMP gene family. Upon analyzing tissue-specific expression patterns, it was determined that PbrVAMP721i demonstrated high expression levels within pear pollen tube and was chosen for further functional analysis. The results of antisense oligodeoxynucleotide (as-ODN) assay showed that PbrVAMP721i could regulated the growth of pear pollen tube by inhibiting the transport of vesicles at the tip of pollen tube. Our findings will clarify the biological function of VAMP gene in pear pollen tube growth. [ABSTRACT FROM AUTHOR]

The article focuses on embed programmed magnetization patterns (magnetization modules) into the adhesive sticker layers to construct soft robots with programmable magnetization profiles and geometries and then integrate spatially distributed functional modules. It mentions test beds are used to explore multimodal robot locomotion and various applications related to environmental sensing and detection, circuit repairing, and gastric ulcer coating.

Polymer dielectric capacitors are widely utilized in pulse power devices owing to their high power density. Because of the low dielectric constants of pure polymers, inorganic fillers are needed to improve their properties. The size and dielectric properties of fillers will affect the dielectric breakdown of polymer‐based composites. However, the effect of fillers on breakdown strength cannot be completely obtained through experiments alone. In this paper, three of the most important variables affecting the breakdown strength of polymer‐based composites are considered: the filler dielectric constants, filler sizes, and filler contents. High‐throughput stochastic breakdown simulation is performed on 504 groups of data, and the simulation results are used as the machine learning database to obtain the breakdown strength prediction of polymer‐based composites. Combined with the classical dielectric prediction formula, the energy storage density prediction of polymer‐based composites is obtained. The accuracy of the prediction is verified by the directional experiments, including dielectric constant and breakdown strength. This work provides insight into the design and fabrication of polymer‐based composites with high energy density for capacitive energy storage applications. [ABSTRACT FROM AUTHOR]

Adaptations can endow species with complex traits that enable them to occupy new niches. To adapt to the arboreal lifestyle, treefrogs have evolved a suite of complex traits for climbing and gliding; to date, however, the molecular mechanisms underpinning these adaptations are unknown. Here, based on two de novo-assembled Asian treefrog genomes, genes related to limb development showed evidence of accelerated evolution. Furthermore, the PPL gene that regulates the keratin cytoskeleton showed conservative substitution within the genus Rhacophorus. These genetic changes contribute to limb and toe-pad morphogenesis, providing fundamental adaptations for climbing and grasping. Behavioral and morphological comparisons clarified the gliding function of interdigital webbing and the different developmental patterns between fully and weakly webbed feet. Time-ordered gene coexpression network analysis of gliding Rhacophorus kio and nongliding Rhacophorus dugritei tadpoles revealed specific coexpression patterns for fully webbed feet, which involved the Wnt signaling and vascular remodeling pathways. These findings highlight the molecular basis of phenotypes that facilitate expansion into new niches and provide insights into the importance of local adaptation in shaping phenotypes and locomotion patterns. [ABSTRACT FROM AUTHOR]

With the wide application of energy storage equipment in modern electronic and electrical systems, developing polymer-based dielectric capacitors with high-power density and rapid charge and discharge capabilities has become important. However, there are significant challenges in synergistic optimization of conventional polymer-based composites, specifically in terms of their breakdown and dielectric properties. As the basis of dielectrics, all-organic polymers have become a research hotspot in recent years, showing broad development prospects in the fields of dielectric and energy storage. This paper reviews the research progress of all-organic polymer dielectrics from the perspective of material preparation methods, with emphasis on strategies that enhance both dielectric and energy storage performance. By dividing all-organic polymer dielectrics into linear polymer dielectrics and nonlinear polymer dielectrics, the paper describes the effects of three structures (blending, filling, and multilayer) on the dielectric and energy storage properties of all-organic polymer dielectrics. Based on the above research progress, the energy storage applications of all-organic dielectrics are summarized and their prospects discussed. [ABSTRACT FROM AUTHOR]

This article designs a fully distributed resilient control method for networked multigroup systems in the face of unknown unbounded false data injection (FDI) attacks. The considered multigroup systems contain cooperative agents and adversarial attackers. FDI attacks on the multigroup systems include unknown unbounded injections on the local feedback state and communication channels among the network topology. A fully distributed resilient control method is proposed to guarantee the uniformly ultimately bounded containment convergence. In particular, the proposed method consists of the original cyber-physical layer and a virtual resilient layer. The method is further refined to deal with the case when both cyber-physical and virtual layers are subjected to unknown unbounded attacks. The efficacy of the proposed results is first validated on two simulation examples for both linear and nonlinear multigroup systems, and then evaluated on a modified IEEE 34-bus feeder system, emulated in a controller/hardware-in-the-loop experimental platform, to regulate frequency and voltage for islanded microgrid against malicious attacks. [ABSTRACT FROM AUTHOR]

In this article, we investigate a novel reinforcement-learning (RL)-based scheme to address the optimal leader–follower consensus issue for constrained-input continuous-time multiagent systems. First, as for input-constrained problems, the fundamental smooth assumption is not satisfied for the value function. To deal with this problem, we employ the method of vanishing viscosity solutions to relax this smooth assumption to a continuity assumption for the value function, which broadens the scope of RL applications. Second, the control cost functions take a more general form which guarantees the continuity of the optimal control policy instead of the specific integrand form used in previous input-constrained RL-based schemes. Based on these results, we introduce a novel identifier–critic–actor structure to extend the conventional critic–actor RL framework into a distributed model-free one, where the learning of the identifier, critic, and actor is online and simultaneous. We provide the simulation examples to validate the effectiveness of the proposed scheme. [ABSTRACT FROM AUTHOR]

The problem of enhanced stabilization of discrete-time Takagi–Sugeno fuzzy system is investigated in depth via proposing a new way to employ much more information implied in various time-varying differences of multi-instant normalized fuzzy weighting functions. Benefit from the given comprehensive real-time scheduling model, these time-varying differences on time vertical dimension and two different transverse dimensions are for the first time integrated into fuzzy stabilization and two key alterable weights are also introduced. Consequently, much considerable freedom can be produced and, thus, it brings much less conservative results than the reported ones in recent literature. More importantly, a very simple workable way has been provided to online recognize the specific enabled mode at each sampling instant so that those existing time-consuming online operations in referred literature can be avoided to ease online implementation costs. Indeed, this feature is very beneficial to the practical application of our theoretical results. Finally, the superiority of our developed method over previous ones is validated adequately via two benchmark simulations. [ABSTRACT FROM AUTHOR]

The difference in the shear strength and other characteristics of the cohesive soil containing calcareous nodules (CSCN) between samples with large size and corresponding scaling size, which is called scaling effect, is significantly affected by its calcareous nodule content (CNC) of the gradation composition. However, current researches rarely reveal the influence of the CNC on the scaling effect in shear strength of samples. In this study, how and why the CNC affects the scaling effect in shear strength were explored. Then a method to reduce the scaling effect based on the reason for influence was proposed. Results show that the correlation between the scaling effect in shear strength and the CNC presents a step curve. This is attributed to that it is easier to form a skeleton effect in samples with scaling size for the same CNC. Considering the skeleton effect, a calculation model for the shear strength parameters of CSCN samples with large size is proposed to reduce the scaling effect. This paper demonstrates that the proposed calculation model provides an access to obtain calculated shear strength parameters of CSCN samples with large size by using measured results of samples with corresponding scaling size. [ABSTRACT FROM AUTHOR]

Relative states between neighbors are ubiquitous in large-scale systems, and the relative state saturations need to be considered when designing controllers based on this relative state information. This article investigates the consensus control of the delayed multiagent systems under the relative state saturations. By means of an incidence matrix, the consensus under the relative state saturations is transformed into the stability of edge dynamics operating on constrained sets. To enable the edge states to stay within the constrained sets, a novel nonlinear protocol is designed by embedding an elaborate saturation function. Sufficient conditions are identified, under which not only consensus is achieved but also relative state saturations do not occur. Moreover, this analytical result can address the consensus problem while preserving connectivity, within the limited communication range framework. Simulations illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

As far as we know, there have been no studies exploring the association between maternal sulfur dioxide (SO2) exposure and the risk of hypospadias in offspring. We aimed to evaluate this association during the 3 months before conception and the first trimester. A population‐based case–control study was conducted in male infants, consisting of 348 cases of hypospadias and 4023 controls. Maternal exposure to SO2, particulate matter with aerodynamic diameters ≤10 μm (PM10), and nitrogen dioxide (NO2) was assessed by averaging the concentrations recorded at all stations in the mother's city of residence. Air pollutants were tested for multicollinearity using variance inflation factor analysis. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by multivariable logistic regression models. SO2 exposure during the 3 months before conception was significantly associated with the risk of hypospadias (highest tertile: OR = 7.40, 95% CI: 3.54–15.62). When focusing on shorter exposure windows, similar associations were observed for SO2 exposure in the first and second month before and the first month after conception. In conclusion, maternal exposure to SO2 during the 3 months before and the first and second months after conception may increase the risk of hypospadias in offspring. [ABSTRACT FROM AUTHOR]

This article investigates the consensus tracking of exponentially unstable multiagent systems with time-varying input delay. The truncated predictor feedback approach is utilized for designing delay-dependent state and output feedback protocols. And the explicit conditions that can realize consensus tracking are established in terms of parametric Lyapunov equations and scalar inequalities. Besides, the protocol design algorithms under the maximum allowable delay and the maximum convergence rate are, respectively, provided. Compared with the existing results, the salient characteristic of the current results is to reveal the quantitative relationship among the time delay, unstable plant, network topologies, and the convergence rate. Specifically, for achieving the consensus tracking, the synchronization force from network connectivity needs to dominate the anti-synchronization force from unstable open-loop poles and input delays; the maximum allowable input delay is inversely proportional to the sum of the unstable open-loop poles; the convergence rate becomes smaller as the input delay bounds or/and the sum of the unstable poles in plant increase. Numerical simulations confirm the effectiveness of the proposed theoretical design. [ABSTRACT FROM AUTHOR]

Non-hydraulic root source signaling (nHRS) is a unique positive response to soil drying in the regulation of plant growth and development. However, it is unclear how the nHRS mediates the tradeoff between source and sink at the late growth stages and its adaptive mechanisms in primitive wheat. To address this issue, a root-splitting design was made by inserting solid partition in the middle of the pot culture to induce the occurrence of nHRS using four wheat cultivars (MO1 and MO4, diploid; DM22 and DM31, tetraploid) as materials. Three water treatments were designed as 1) both halves watered (CK), 2) holistic root system watered then droughted (FS), 3) one-half of the root system watered and half droughted (PS). FS and PS were designed to compare the role of the full root system and split root system to induce nHRS. Leaves samples were collected during booting and anthesis to compare the role of nHRS at both growth stages. The data indicated that under PS treatment, ABA concentration was significantly higher than FS and CK, demonstrating the induction of nHRS in split root design and nHRS decreased cytokinin (ZR) levels, particularly in the PS treatment. Soluble sugar and proline accumulation were higher in the anthesis stage as compared to the booting stage. POD activity was higher at anthesis, while CAT was higher at the booting stage. Increased ABA (nHRS) correlated with source-sink relationships and metabolic rate (i.e., leaf) connecting other stress signals. Biomass density showed superior resource acquisition and utilization capabilities in both FS and PS treatment as compared to CK in all plants. Our findings indicate that nHRS-induced alterations in phytohormones and their effect on source-sink relations were allied with the growth stages in primitive wheat. [ABSTRACT FROM AUTHOR]

Refractory metal diboride is a kind of excellent ultra-high temperature ceramics and could be applied as thermal shielding material for supersonic aircraft. In this paper, a two-step reaction process for the synthesis of refractory metal diboride powders was proposed using refractory metal oxide, carbon black (C), B 4 C, and calcium Ca as raw materials. Firstly, the carbothermal reduction reaction between oxides and C was taken place at 1773 K; and then, the reduction product was reacted with B 4 C and Ca for the purposes of boronization and decarburization. After acidic leaching, pure diboride was prepared. The experimental results indicated that diborides of Ti, Zr, Hf, V, Nb and Ta with low residual carbon content can be prepared by this method. In addition, the inheritance relationship of particle size between raw oxide and finally prepared diboride was revealed. By this method, ultra-fine TiB 2 (123 nm) and ZrB 2 (76 nm) powders were also successfully prepared, with the raw materials of nano TiO 2 and nano ZrO 2 , respectively. [ABSTRACT FROM AUTHOR]

Polymer dielectric capacitors, with their high energy storage density and fast release of energy, have recently received increasing attention for their ability to meet the critical requirements of pulsed power devices in low-consumption systems. In this context, this paper reports that surface-modified single-walled carbon nanotubes (SWCNT) were successfully synthesized and used as fillers to improve the energy storage and mechanical performance of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP)-based composites. The PVDF-HFP/SWCNT composites realize high dielectric constants and low percolation thresholds of 62 and 0.25, respectively. In particular, when composites possess an SWCNT content of only 0.4 vol.%, an acceptable energy storage density of 0.24 J/cm3 at a low electric field of 700 kV/cm along with a high energy storage efficiency (74%) is also observed. Meanwhile, the tensile strength and breaking elongation are 44 MPa and 8.1%, respectively. According to detailed characterization results, SWCNT with low filling are uniformly dispersed and show a certain orientation in PVDF-HFP after surface modification, which is the key to improve the composite performance. These results provide an effective method for fabricating flexible-polymer composites with a high density of energy storage. In the current study, the surface-modified single-walled carbon nanotubes were successfully synthesized and used as fillers to improve the energy storage and mechanical performance of poly(vinylidene fluoride-co-hexafluoropropylene)-based composites. SWCNT with low filling is uniformly dispersed and shows a certain orientation in PVDF-HFP after surface modification, which is the key to improving the composite performance. This work may open a pathway to meet the needs of pulsed power devices in a low electric field. [ABSTRACT FROM AUTHOR]

Hybrid and intermittent characteristics of the distributed energy resources (DERs) bring great challenges to the security control and economic dispatch (ED) of the microgrids. To bypass these hurdles, this article proposes a multiagent system-based integrated design of security control and ED to guarantee the effective and economical operation of the interconnected microgrids. First, a hierarchical control scheme is constructed by two-level unit agents, in which the switching control and dynamic regulation are fully implemented with the corresponding hybrid behaviors based on the differential hybrid Petri-net (DHPN) model. Based on the DHPN model, a novel dynamic ED integrated with security control is proposed to overcome the issues that cannot be solved in conventional models. Furthermore, to reduce the computational complexity and unified the mathematical model of the DERs, the inverter-based power control strategy is converted to a predictive control model which can be decomposed into several subsystems. In the optimization process, all the subsystems are implemented in a fully distributed, communication free, and rolling optimization manner based on the distributed model predictive control (DMPC). The validity of the proposed design is demonstrated according to the simulation results in case studies. [ABSTRACT FROM AUTHOR]

The stochastic nature of intermittent energy resources has brought significant challenges to the optimal operation of the hybrid energy systems. This article proposes a probabilistic multiobjective evolutionary algorithm based on decomposition (MOEA/D) method with two-step risk-based decision-making strategy to tackle this problem. A scenario-based technique is first utilized to generate a stochastic model of the hybrid energy system. Those scenarios divide the feasible domain into several regions. Then, based on the MOEA/D framework, a probabilistic penalty-based boundary intersection (PBI) with gradient descent differential evolution (GDDE) algorithm is proposed to search the optimal scheme from these regions under different uncertainty budgets. To ensure reliable and low risk operation of the hybrid energy system, the Markov inequality is employed to deduce a proper interval of the uncertainty budget. Further, a fuzzy grid technique is proposed to choose the best scheme for real-world applications. The experimental results confirm that the probabilistic adjustable parameters can properly control the uncertainty budget and lower the risk probability. Further, it is also shown that the proposed MOEA/D-GDDE can significantly enhance the optimization efficiency. [ABSTRACT FROM AUTHOR]

Within the multiagent systems framework, the relative states between neighbors can be acquired by some on-board sensors, and then the relative state saturations inevitably occur due to the limited sensing capabilities. This paper investigates the consensus problem of nonlinear multiagent systems subject to the relative state saturations. Utilizing the incidence matrix and the edge Laplacian, the consensus problem of nonlinear multiagent systems with the relative state saturations can be cast into the stabilization problem of edge dynamics operating on the constrained set. Three types of protocols, namely continuous, intermittent, and adaptive state feedback protocols are, respectively, proposed for achieving the constrained consensus, and meanwhile yielding consensus values. A consensus analysis is provided by virtue of state saturation theory, switched system theory, adaptive theory, and Lyapunov stability theory. Output feedback protocol is also designed. Finally, the obtained results are applied to connectivity preservation for first-order nonlinear multiagent systems, despite the presence of limited communication range and input constraints. The theoretical results are validated by two simulation examples. [ABSTRACT FROM AUTHOR]

Background: Apparent diffusion coefficient (ADC) value is an important quantitative parameter in the research of cervical cancer, affected by some factors. Purpose: To investigate the effect of pathological type and menstrual status on the ADC value of cervical cancer. Material and Methods: A total of 352 individuals with pathologically confirmed cervical cancer between January 2015 to December 2017 were retrospectively enrolled in this study, including 317 cases with squamous cell carcinomas (SCC) and 35 cases with adenocarcinomas (AC); 177 patients were non-menopausal and 175 were menopausal. All patients underwent a routine 3.0-T magnetic resonance imaging (MRI) scan and diffusion-weighted imaging (DWI) examination using b-values of 0, 800, and 1000 s/mm². Three parameters including mean ADC (ADCmean), maximum ADC (ADCmax), and minimum ADC (ADCmin) of cervical cancer lesions were measured and retrospectively analyzed. Independent samples t-test was used to compare the difference of ADC values in different menstrual status and pathological types. Results: In all menopausal and non-menopausal patients, the ADCmean and ADCmin values of SCC were lower than those of AC (P<0.05), the ADCmax of two pathological types showed no statistical difference (P > 0.05). In menopausal patients, the ADCmean, ADCmax, and ADCmin values of SCC were not statistically different compared with those of AC (P > 0.05). The ADCmean, ADCmax, and ADCmin values of different pathological types cervical cancers in non-menopausal patients were all higher than those in menopausal patients (P<0.05). Conclusion: The ADC values of the cervical cancers were different in different pathological types and were also affected by menstrual status. [ABSTRACT FROM AUTHOR]

This paper focuses on the resilient ${H_{\infty }}$ filter design for event-triggered networked systems subject to nonperiodic denial-of-service (DoS) jamming attacks. In this paper, a new resilient event-triggered transmission strategy is first proposed to improve the efficiency of network resource utilization while counteracting the nonperiodic DoS jamming attacks. Then, by using a time-delay approach, the filtering error system is modeled as a switched system, which characterizes the effects of the event-triggering scheme and nonperiodic DoS jamming attacks simultaneously. Based on the established model, by using the piecewise Lyapunov–Krasovskii functional method, linear matrix inequality (LMI)-based sufficient conditions are formulated to achieve the globally exponential stability as well as the weighted ${H_{\infty }}$ performance of the resulting switched system under the DoS jamming attacks. Consequently, the co-design method for the desired filter parameters and event-triggering parameters can be formulated provided that the above LMIs are feasible. Finally, the effectiveness of the proposed method is demonstrated by a practical example. [ABSTRACT FROM AUTHOR]

Background: Computed tomography perfusion (CTP) can provide information on blood perfusion as a reliable marker of tumor response to therapy. Purpose: To assess the role of volume CTP (vCTP) parameters in predicting treatment response to concurrent chemoradiotherapy (CCRT) for cervical cancer. Material and Methods: Thirty-three patients with cervical cancer underwent vCTP. Three CTP parameters of cervical cancer--including arterial flow (AF), blood volume (BV), and permeability surface (PS)--were measured in two different ways: the region of interest incorporating the "local hot" with the highest enhancement and "cold spot" with the lowest enhancement; and "whole-tumor" measurements. The patients were divided into non-residual and residual tumor groups according to the short-term response to treatment. The clinical and perfusion parameters were compared between the two groups. Results: There was no significant difference in age, body mass index, FIGO stage, pathological grade, or pretreatment tumor size between the two groups (P > 0.05). The non-residual tumor group had higher pretreatment AF in high-perfusion and low-perfusion subregions than the residual tumor group (P <0.05), but the AF in whole-tumor regions was not different between the two groups (P > 0.05). There were no differences in BV and PS between the two groups (P > 0.05). The diagnostic potency of AF in the low-perfusion subregion was higher than that in the high-perfusion subregion. Conclusion: vCTP parameters are valuable for the prediction of short-term effects. The AF in the low-perfusion subregion was a more effective index for predicting treatment response to CCRT of cervical cancer. [ABSTRACT FROM AUTHOR]

• Based on the first-principles ab initio calculation method of density functional theory (DFT), the adsorption models of Cl 2 molecules on the TiC (100) intact surface and the surface with carbon vacancy are established. • This work shows the process of dissociation of chlorine gas on the surface of TiC (100) and its interaction with the Ti and C atoms on the surface. • The research results indicate th the intermediate products of titanium chloride are more easily dissociated from the surface of TiC (100) in the form of TiCl 3 , and further chlorinated to form TiCl 4 under the action of chlorine gas. It is important to study the adsorption behavior of Cl 2 molecules on the TiC surface and the formation and transfer of reaction products to understand and to regulate the low-temperature chlorination reaction process of carbonized titanium-bearing slag. Based on the first-principles ab initio calculation method of density functional theory (DFT), the adsorption models of Cl 2 molecules on the TiC (100) intact surface and the surface with carbon vacancy are established, and the adsorption structures, electronic properties, differential charge density and partial density of states (PDOS) are calculated and analyzed. The formation process and the optimal formation path of the adsorption reaction product are explored. The investigated results indicate that the Cl atoms in the system bonded to the surface Ti atoms are more stable than the structure formed by bonding to the surface C atoms. The electron flow direction is Ti → C and Ti → Cl. In the reaction of TiC with Cl 2 molecules, the TiCl 3 intermediate is easier to form than the TiCl 2 intermediate. The energy barrier to be overcome to form the TiCl 3 intermediate is lower and the energy to be supplied is easily met by external conditions. TiCl 3 is then further chlorinated to form TiCl 4. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper addresses the problem of reducing the conservatism for stabilization of discrete-time Takagi–Sugeno fuzzy systems via a new extended representation approach. Different from previous slack variable methods, an advanced slack variable method without limitations is proposed for further making good use of available fuzzy weighting functions. Owing to the introduction of extended representations for homogenous polynomials, those strong limitations in recent literature are relaxed and thus the primary and secondary sequences of all normalized fuzzy weighting functions can be mapped to one augmented multi-indexed matrix for each homogeneous polynomial. Therefore, less conservative stabilization conditions can be provided as a result of these effective measures and thus a part of the online computational cost is transferred to the offline implementation. Finally, the benefits of the proposed method are illustrated by means of numerical experiments. [ABSTRACT FROM AUTHOR]

Resilient dynamic event‐triggered control design problem is concerned for frequency stabilisation of multi‐area power systems with renewable energy penetration under transmission delay and denial‐of‐service (DoS) attacks. The main works are presented as followings: (1) A novel state‐space model is established to describe multi‐area power systems with solar and wind generation disturbance under load frequency control and virtual inertia control (LFC‐VIC). (2) The influence of DoS attacks is considered and first modelled by model‐based average dwell time (MDADT). A criterion of preserving desired exponential H∞ performance is obtained about the required lower bound of average dwell time (ADT) of sleep intervals, namely τF>ln⁡λ0/α1 and the tolerable upper bound of ADT of attack intervals, namely τD<−(ln⁡λ1+(α0+α1)dM)/α0. (3) To reduce communication load, a dynamic event‐triggered mechanism (DETM) is proposed and designed jointly with resilient LFC‐VIC scheme by using piecewise Lyapunov–Krasovskii functional method and LMIs technique. (4) To defence DoS attacks actively, based on the resulting MDADT criterion, a dynamic prediction strategy is proposed to compensate the packet drops with unknown bound subjected to attack strategy. Finally, a numerical example for a two‐area power system is carried out to verify the designed resilient LFC‐VIC scheme and the DETM. [ABSTRACT FROM AUTHOR]

Radiative feedbacks depend on the spatial patterns of sea surface temperature (SST) and thus can change over time as SST patterns evolve—the so-called pattern effect. This study investigates intermodel differences in the magnitude of the pattern effect and how these differences contribute to the spread in effective equilibrium climate sensitivity (ECS) within CMIP5 and CMIP6 models. Effective ECS in CMIP5 estimated from 150-yr-long abrupt4×CO2 simulations is on average 10% higher than that estimated from the early portion (first 50 years) of those simulations, which serves as an analog for historical warming; this difference is reduced to 7% on average in CMIP6. The (negative) net radiative feedback weakens over the course of the abrupt4×CO2 simulations in the vast majority of CMIP5 and CMIP6 models, but this weakening is less dramatic on average in CMIP6. For both ensembles, the total variance in the effective ECS is found to be dominated by the spread in radiative response on fast time scales, rather than the spread in feedback changes. Using Green’s functions derived from two AGCMs shows that the spread in feedbacks on fast time scales may be primarily due to differences in atmospheric model physics, whereas the spread in feedback evolution is primarily governed by differences in SST patterns. Intermodel spread in feedback evolution is well explained by differences in the relative warming in the west Pacific warm-pool regions for the CMIP5 models, but this relation fails to explain differences across the CMIP6 models, suggesting that a stronger sensitivity of extratropical clouds to surface warming may also contribute to feedback changes in CMIP6. [ABSTRACT FROM AUTHOR]

This paper is concerned with distributed event-triggered consensus of a generally linear multi-agent system subjected to periodic denial-of-service (DoS) jamming attacks. First, a novel switched time-varying delay system model is established to describe consensus error dynamics. By virtue of the switched system and time delay system approaches, one constraint is obtained as a tradeoff between exponential convergence rate of consensus error and uniform lower bound of sleep intervals of periodic DoS jamming attacks. Second, sufficient conditions are derived to guarantee exponential consensus of the multi-agent system. Third, a co-design method is presented to determine the parameters of both the distributed event-triggered mechanism and consensus protocol. Furthermore, an algorithm is given to find the allowable uniform lower bound of sleep intervals and suboptimal distributed event-triggering parameters. Finally, an illustrative example is provided to verify the effectiveness of the proposed resilient event-triggering consensus design method against periodic DoS jamming attacks. [ABSTRACT FROM AUTHOR]

The observed rate of global warming since the 1970s has been proposed as a strong constraint on equilibrium climate sensitivity (ECS) and transient climate response (TCR)--key metrics of the global climate response to greenhouse-gas forcing. Using CMIP5/6 models, we show that the inter-model relationship between warming and these climate sensitivity metrics (the basis for the constraint) arises from a similarity in transient and equilibrium warming patterns within the models, producing an effective climate sensitivity (EffCS) governing recent warming that is comparable to the value of ECS governing long-term warming under CO2 forcing. However, CMIP5/6 historical simulations do not reproduce observed warming patterns. When driven by observed patterns, even high ECS models produce low EffCS values consistent with the observed global warming rate. The inability of CMIP5/6 models to reproduce observed warming patterns thus results in a bias in the modeled relationship between recent global warming and climate sensitivity. Correcting for this bias means that observed warming is consistent with wide ranges of ECS and TCR extending to higher values than previously recognized. These findings are corroborated by energy balance model simulations and coupled model (CESM1-CAM5) simulations that better replicate observed patterns via tropospheric wind nudging or Antarctic meltwater fluxes. Because CMIP5/6 models fail to simulate observed warming patterns, proposed warming-based constraints on ECS, TCR, and projected global warming are biased low. The results reinforce recent findings that the unique pattern of observed warming has slowed global-mean warming over recent decades and that how the pattern will evolve in the future represents a major source of uncertainty in climate projections. [ABSTRACT FROM AUTHOR]

In this paper, an integral reinforcement learning-based value iteration algorithm is developed for solving the infinite horizon optimal tracking control problem of nonlinear continuous-time systems with time delay. The main idea is using the value iteration technique to obtain the iterative control law, which optimizes the iterative performance index function. In contrast to the existing value iteration algorithms, the proposed IRL-based value iteration algorithm takes the time delay into account. Second, the convergence analysis of the proposed algorithm is given for the nonlinear continuous-time systems with time delay. Moreover, the critic neural network is utilized to approximate the performance index function and compute the optimal control law for facilitating the implementation of the iterative algorithm. Finally, the simulation results are presented to illustrate the effectiveness of the developed method. [ABSTRACT FROM AUTHOR]

By means of advanced information and communication technology, cyber‐physical power systems can attain real‐time monitor and control but have to suffer the damage caused by a cyber attack. In this study, the authors' define attack efficiency to evaluate attack paths that attacker may adopt to intrude systems, to find the most efficient attack paths (i.e. the most vulnerable paths). Based on the actual power grid and security stability control system, the coupling model of cyber‐physical power systems is established to analyse the propagation of cascading failure within and across the physical power grid and communication network. In the attack model, the attack cost matrix is built to describe the cost between directly connected nodes in a communication network. Furthermore, considering the probability that control commands are successfully transmitted from router nodes to generator/substation nodes, the total attack cost from the communication network to the physical power grid is figured out. To search for the most vulnerable attack paths in systems, the attack efficiency is proposed to quantify the relation between attack cost and attack gain, wherein the attack gain is the damage on systems caused by the cyber attack. [ABSTRACT FROM AUTHOR]

This article proposes a generalized modeling and simulation approach for correlated synthetic aperture radar (SAR) texture based on the Gaussian coherent scatterer model. It is rooted in the physics-based coherent scatterer assumption where each observation in an SAR image is a coherent sum of multiple underlying Gaussian scatterers. The proposal generalizes existing single-point statistical models by allowing the number of scatterers to be a correlated random field. It can also generate the desired spatial correlation texture by stipulating the structure in both the Gaussian scattered field and the number of scatterers. This generalized model is derived theoretically and then validated by both simulations and experiments with SAR data from actual sensors. [ABSTRACT FROM AUTHOR]

In cyber‐physical power systems, tiny failure occurring in the communication network could propagate to affect the operation of the physical power grid through inter‐links and even cause catastrophic blackouts. The authors propose a partial random coupling systems model to study the vulnerability of nodes and connectivity of systems in a cascading failure. In terms of traffic loads generated in systems, they employ load spill index to analyse dynamic states of nodes in cascading failure. In cascading failure, considering the effect from a communication network, vulnerability matrices are established to study the vulnerability of nodes in the physical power grid. Furthermore, an efficiency index is defined to analyse connectivity of systems. In the numerical simulation, they verify the accuracy of the proposed evaluation approach and test its scalability and universality in different power systems. [ABSTRACT FROM AUTHOR]

Summary: The distributed optimal frequency regulation of power grid containing plenty of distributed renewable energy resources is highly dependent on the communication network. However, the utilization of a communication network makes the power grid vulnerable to cyberattacks, which could deteriorate the control performance and even cause the failure of a control task. To address this problem, this paper investigates the secure distributed optimal frequency regulation of power grid under cyberattack. The stealthy deceptive cyberattack model is constructed, and its perniciousness on optimal frequency regulation is analyzed. A novel type of secure distributed optimal frequency regulation is developed by introducing a secure‐based communication network to improve the resilience against cyberattack. It is proved theoretically that the secure regulation can restore the frequency deviation of each area to zero and minimize the total generation cost to retain the economic efficiency even under cyberattack. Simulation result shows the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

Considering the limitation of communication network, the event‐triggered mechanism based distributed optimal frequency regulation is proposed, which can restore the frequency and retain the economic efficiency of power grid simultaneously under certain load disturbances. Compared with the traditional distributed optimal frequency regulation based on continuous or periodic sampled‐data information transmission mechanism, the communication burden among the areas in power grid is reduced since two novel types of event‐triggered mechanisms, which possess the information demand‐transmission property, are constructed and introduced in the regulation method in this study. Moreover, Zeno behaviour is proved to be avoided in order to guarantee the availability of event‐triggered mechanisms in practical power grid. The effectiveness of theoretical result of this study is verified by the simulation study. [ABSTRACT FROM AUTHOR]

This study is concerned with resilient load frequency control (LFC) scheme design of multi‐area power systems with communication delay and aperiodic denial‐of‐service (DoS) attacks. First, to identify DoS attacks, a detection mechanism in the actuator side is proposed which is a time counter measuring the input delay. The identified DoS attacks are constrained by its upper bound of frequency and duration. When DoS attacks are identified, actuator switches to zero‐input strategy from hold‐input strategy. According to the switching control inputs, switched time delay system model is established to describe the attack influence on LFC system. Further, a criterion of preserving weighted H∞ performance is derived by combining piecewise Lyapunov–Krasovskii functional method with switched system method. Based on the criterion, the resilient control gain is designed by solving a set of LMIs. Finally, numerical simulations are given to verify the validness of the attack detection based resilient LFC scheme. [ABSTRACT FROM AUTHOR]

Cascading failure in interdependent networks is studied in recent decade, and considerable research has been done on systems modeling, vulnerability analysis and protection strategy, but partial work on vulnerability analysis and protection strategy still cannot completely utilize coupling relation between physical power grid and communication network into research, thus we introduce inter-relation of support nodes to perfect the strategies. Compared with traditional vulnerability analysis, we, through studying state of systems after attack, analyze robustness of systems. From the perspective of attacker, four attack strategies considering inter-relation have been proposed, and simulation results verify the serious destructiveness of attack strategies to steady of systems. Taking inter-relation and heterogeneity of networks into consideration, we propose two redundancy protection strategies on intra-links redundancy. Both protection strategies are proved to attain better performance than other strategies without considering inter-relation, meanwhile existence of saturation point can give guidance on rational allocation of limited intra-links. • Four optimizing attack strategies are proposed to detect critical nodes. • Cascading failure is simulated in four coupled symmetric networks. • Two optimizing intra-links addition strategies are raised. • The effectiveness of optimizing attack and intra-links addition strategies. • Discovery of saturation point has guide in rationally allocating limited resource. [ABSTRACT FROM AUTHOR]