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This study, reliant on practical projects, conducts an in-depth analysis of key technologies amid the construction of prefabricated viaducts. The primary focus is on the integrated hoisting, positioning, and control techniques for the bridge abutments and pier columns, culminating in a proposal of an innovative integrated and prefabricated construction approach. This approach optimizes the construction process and methods by factoring in the structural characteristics of different types of pier columns and addressing construction challenges. Simultaneously, it underscores the significance of material selection, prefabricated component design, and innovative construction techniques. The study also explores on-site management and quality control strategies to ensure the efficiency and safety of the construction process. The research indicates that this approach significantly improves construction efficiency, reduces safety risks, and solidly guarantees structural quality. These findings offer crucial theoretical and practical guidance for advancing the industrialization, modularization, and innovative development of construction techniques in bridge construction. They contribute to the continual optimization of technical innovation and engineering practices in the field of bridge construction.

These days, the increasing incremental cost consensus-based algorithms are designed to tackle the economic dispatch (ED) problem in smart grids (SGs). However, one principal obstruction lies in privacy disclosure for generators and consumers in electricity activities between supply and demand sides, which may bring great losses to them. Hence, it is extraordinarily essential to design effective privacy-preserving approaches for ED problems. In this article, we propose a two-phase distributed and effective heterogeneous privacy-preserving consensus-based (DisEHPPC) ED scheme, where a demand response (DR)-based framework is constructed, including a DR server, data manager, and a set of local controllers. The first phase is that Kullback–Leibler (KL) privacy is guaranteed for the privacy of consumers’ demand by the differential privacy method. The second phase is that $({\varepsilon,\delta })$ -privacy is, respectively, achieved for the generation energy of generators and the sensitivity of electricity consumption to electricity price by designing the privacy-preserving incremental cost consensus-based (PPICC) algorithm. Meanwhile, the proposed PPICC algorithm tackles the formulated ED problem. Subsequently, we further carry out the detailed theoretical analysis on its convergence, optimality of final solution, and privacy degree. It is found that the optimal solution for the ED problem and the privacy preservation of both supply and demand sides can be guaranteed simultaneously. By evaluation of a numerical experiment, the correctness and effectiveness of the DisEHPPC scheme are confirmed. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 is still continuing and may affect stroke emergency care. We aim to investigate the impact of pandemic on stroke treatment in tertiary stroke centers in western China, and to quantitatively evaluate the worldwide influence with a meta-analysis. The original part was conducted in three tertiary stroke centers in Sichuan province. We compared emergency visits and efficiency of stroke treatment pre-, early, peak and late pandemic. Single-center analysis was further conducted in the largest local hospital and one hospital located close to the epicenter respectively. Relevant studies were searched in PubMed, Ovid Embase and Cochrane Library for English publications from December 2019 to July 2020 for systematic review. Fixed-and random-effect meta-analysis was performed to calculate the overall rates. Totally current original study showed fewer time of hospital admission and significantly higher rates of mechanical thrombectomy during the early and peak epidemic periods, compared with pre-epidemic time. The largest local hospital had significantly higher mechanical thrombectomy rates during the whole crisis and less daily admission during early and peak epidemic periods. The hospital located close to the epicenter presented higher proportions of intravenous thrombolysis since outbreak, and more favorable outcomes after reperfusion therapies than later (all P values <0.05). In meta-analysis, studies reported differences in reperfusion therapies and stroke severity but pooled results were non-significant. Overall, comprehensive measures should be implemented to keep hospital's capacity to deliver high-quality stroke emergency care during the global pandemic. Some key messages were provided for medical practice in the crisis. [ABSTRACT FROM AUTHOR]

Highlights • The spreading characteristics of cyber rumors over mobile social networks are addressed. • A new compartmental compartmental model for cyber rumor spreading is developed. • Rumor-denier's behavior of refuting rumors is incorporated. • The dynamic properties of the model are analyzed. • Numerical simulations illustrate theoretical results and indicate suggestions for inhibiting rumours spreading. Abstract By incorporating the spreading characteristics of cyber rumors over mobile social networks, we newly develop a dynamic system to model rumor spreading dynamics by the compartment method. Specifically, a couple of a user and an attached device is viewed as a node, and all network nodes are separated into four compartments: Rumor-Neutral, Rumor-Received, Rumor-Believed and Rumor-Denied. Some transition parameters among these groups are introduced. Additionally, the role of memory, user's ability to distinguish the rumors and rumor-denier's behavior of refuting rumors are also incorporated. The stability of the equilibria of the model system is addressed, and the influence of model parameters upon the threshold is analyzed. Finally, numerical simulations illustrate the theoretical results, and also motivate us to propose suitable measures to control cyber rumor spreading by properly adjusting the parameter values. [ABSTRACT FROM AUTHOR]

This paper investigates the exponential synchronization of chaotic systems with time delays via periodically intermittent control. Under the new differential inequality, some novel synchronization criteria are derived. In contrast to the existing works, the proposed results are less conservative because they can obtain more precise synchronized rate under the identical control conditions and remove the restrictions on the control period (or the control width) and the time delay. By using special parameters, the feasible region D(ξ), which guarantees the response system synchronizes with the drive system with synchronized rate 0.5ξ, is obtained. The Lu chaotic attractor and a first-order chaotic system with time delay are presented to demonstrate the effectiveness of the proposed results. [ABSTRACT FROM AUTHOR]

In order to analyze the channel estimation performance of near space high altitude platform station (HAPS) in wireless communication system, the structure and formation of HAPS are studied in this paper. The traditional Least Squares (LS) channel estimation method and Singular Value Decomposition-Linear Minimum Mean-Squared (SVD-LMMS) channel estimation method are compared and investigated. A novel channel estimation method and model are proposed. The channel estimation performance of HAPS is studied deeply. The simulation and theoretical analysis results show that the performance of the proposed method is better than the traditional methods. The lower Bit Error Rate (BER) and higher Signal Noise Ratio (SNR) can be obtained by the proposed method compared with the LS and SVD-LMMS methods. [ABSTRACT FROM AUTHOR]

This paper is devoted to exploring the combined impact of a generic nonlinear infection rate and infected removable storage media on viral spread. For that purpose, a novel dynamical model with an external compartment is proposed, and the explanations of the main model assumptions (especially the generic nonlinear infection rate) are also examined. The existence and global stability of the unique equilibrium of the model are fully investigated, from which it can be seen that computer virus would persist. On this basis, a next-best approach to controlling the level of infected computers is suggested, and the theoretical analysis of optimal control of the model is also performed. Additionally, some numerical examples are given to illustrate the main results. [ABSTRACT FROM AUTHOR]

This paper studies some human immunodeficiency virus (HIV) models with switching parameters and pulse control. The classical virus dynamics model is first modified by incorporating switching parameters which are assumed to be time-varying. Some threshold conditions are derived to guarantee the virus elimination by utilizing a Razumikhin-type approach. The results show that the proper switching conditions chosen can increase the counts of CD4+ T-cells while reducing viral load. Pulse control strategies are then applied to the above model. More precisely, the treatment strategy and the vaccination strategy are applied to infected cells and uninfected cells, respectively. Each control strategy is analyzed to gauge its success in achieving viral suppression. Numerical simulations are performed to complement the analytical results and motivate future directions. [ABSTRACT FROM AUTHOR]

In this paper we investigate the stability of neural networks with time-delay and variable-time impulses. A valid approach on calculating the upper bound and lower bound of dwell time is proposed, which is crucial contribution of this paper comparing to previous results on the stability of neural networks with variable-time impulses. Some reasonable sufficient conditions on guaranteeing the global stability of variable-time impulsive neural networks are introduced. These results are also generalized to the case of fixed-time impulse by taking neural networks with fixed-time impulses as the specific form of variable-time impulsive neural networks. Finally, numerical examples are also given to illustrate the effectiveness of our theoretical results. [ABSTRACT FROM AUTHOR]

Wind shear is a dangerous atmospheric phenomenon in aviation. Wind shear is defined as a sudden change of speed or direction of the wind. In order to analyze the influence of wind shear on the efficiency of the airplane, this paper proposes a mathematical model of point target rain echo and weather target signal echo based on Doppler effect. The wind field model is developed in this paper, and the antenna model is also studied by using Bessel function. The spectrum distribution of symmetric and asymmetric wind fields is researched by using the mathematical model proposed in this paper. The simulation results are in accordance with radial velocity component, and the simulation results also confirm the correctness of the established model of antenna. [ABSTRACT FROM AUTHOR]

We adapt the part metric and use it in studying positive solutions of a certain family of discrete dynamic systems. Some examples are presented, and we also compare some results in the literature. [ABSTRACT FROM AUTHOR]

The popularity of the Web improves the growth of web threats. Formulating mathematical models for accurate prediction of malicious propagation over networks is of great importance. The aim of this paper is to understand the propagation mechanisms of web malware and the impact of human intervention on the spread of malicious hyperlinks. Considering the characteristics of web malware, a new differential epidemic model which extends the traditional SIR model by adding another delitescent compartment is proposed to address the spreading behavior of malicious links over networks. The spreading threshold of the model system is calculated, and the dynamics of the model is theoretically analyzed. Moreover, the optimal control theory is employed to study malware immunization strategies, aiming to keep the total economic loss of security investment and infection loss as low as possible. The existence and uniqueness of the results concerning the optimality system are confirmed. Finally, numerical simulations show that the spread of malware links can be controlled effectively with proper control strategy of specific parameter choice. [ABSTRACT FROM AUTHOR]

Land colonization is a major event in plant evolution. Little is known about the evolutionary characteristics of lipids during this process. Here, we proved that Physcomitrella patens , a bryophyte that appeared in the early evolution of terrestrial plants, has short-term desiccation resistance. The maintenance of membrane integrity is related to its specific glycerolipid composition and key genes for lipid metabolism. We analyzed 414 types of lipid molecules, and found that phospholipids accounted for 61.7%, mainly PC and PI; glycolipids accounted for only 26.5%, with a special MGDG molecular map. The most abundant MDGD, that is, MGDG34:6, contained rare 15- and 19-carbon acyl chains; the level of neutral lipids was higher. This was consistent with the results observed by TEM, with fewer lamellae and obvious lipid droplets. Slight dehydration accumulated a large number of TAG molecules, and severe dehydration degraded phospholipids and caused membrane leakage, but PA and MGDG fluctuated less. The key genes of lipid metabolism, DGAT and PAP , were actively transcribed, suggesting that PA was one of the main DAG sources for TAG synthesis. This work proves that Physcomitrella patens adopts high-constitutive PC and PI similar to plant seeds, abundant TAG, and its own specific MGDG to resist extreme dehydration. This result provides a new insight into the lipid evolution of early terrestrial plants against unfavorable terrestrial environments. [Display omitted] • Short-term desiccation resistance naturally exists in Physcomitrella patens. • Highly constitutive PC and PI similar to plant seeds. • Specific MGDG map, the most dominant lipid species contains two odd-numbered acyl chains. • Rapid dehydration accumulates TAG and stimulates the pathway from PA to DAG. • The specific glycerolipid composition establishes the dehydration tolerance of early land plants. [ABSTRACT FROM AUTHOR]

Qarhan Salt Lake contains approximately 296 million tonnes of low-grade solid potash ores. The exploitation and utilization of this low-grade solid potash ore represents the fundamental framework for the sustainable development of Qarhan Salt Lake's potash fertilizer industry. It also alleviates the shortage of potash resources of China. In this paper, we studied species and characteristics of the low-grade solid potash minerals from the Bieletan area in Qarhan Salt Lake and analyzed the solvent that affected the dissolution extraction of low-grade solid potash ore. The major potash minerals in the Bieletan Subbasin are polyhalite, carnallite and sylvite. An effective solvent for dissolving these potash minerals is prepared with old bittern and water from Senie Lake, which contains average Mg2+, Cl−, K+ and Na+ values as 3.69%, 15.23%, 0.23% and 1.60%, respectively. Theoretically calculating by PHREEQC shows that the chemical composition of the solvent is nearly in equilibrium with halite and far away from equilibrium with polyhalite, carnallite and sylvite. This solvent does not significantly cause dissolution and precipitation of halite. Thus its influence on the porosity and permeability of the salt bed in the strata is minimum, which enables the solvent to flow to deeper and farther areas and dissolve more low-grade solid potash ores, showing excellent ability to selectively dissolve K+-bearing saline minerals. After dissolution extraction experiments, the concentration of K+ in the solvent increased from 0.23% to 0.68%, showing the higher-dissolution effect of the solvent for the low-solid potash ores. Hence, the solvent plays an important role in developing of the low-grade potash ores. • The low-grade potash mineral in Bieletan of Qarhan Salt Lake is polyhalite, followed by carnallite and a small amount of sylvite. • The solvent for dissolution extraction of low-grade solid potash ore was prepared with old bittern and natural fresh water, with Mg2+, Cl-, K+ and Na+ geochemical average values of 3.69%, 15.23%, 0.23% and 1.60%, respectively. • The solvent did not influence the porosity and permeability of the salt layer, could flow to deeper and farther areas, and could dissolve more low-grade solid potash minerals. • After dissolution extraction of low-grade solid potash ore, the content of K+ in the solution increased from 0.23% to 0.68%. [ABSTRACT FROM AUTHOR]