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This paper mainly focuses on studying the influence of network characteristics on malware spreading. Firstly, a generalized model with weakly-protected and strongly-protected susceptible nodes is developed by considering the possibility of an intruded node converting back to a weakly-protected susceptible one. The dynamics of the generalized compartmental model is intensively discussed and analyzed, deriving several sufficient conditions for its global stability. Following this work, a novel node-based model is newly proposed to describe malware propagation over an arbitrary connected network including synthesized and real networks. From a microscopic perspective, we establish the novel model by introducing several different variables for each node which describe the probabilities of a node locating at respective states. Our theoretical analysis shows that the largest eigenvalue of the propagating network is a key factor determining malware prevalence. Specifically, the range of the leading eigenvalue can be split into three subintervals in which malware approaches extinction very quickly, or tends to extinction, or persists, depending on into which subinterval the largest eigenvalue of the propagating network falls. Theoretically, the trivial equilibrium of our new node-based model is clearly proved to be exponentially globally stable when the maximum eigenvalue is less than a threshold. We also illustrate the predictive effectiveness of our model by designing some numerical simulations on some regular and scale-free networks. Consequently, we conclude that malware prevalence can be effectively prevented by properly adjusting the spreading network, e.g., reducing the number of nodes and deleting some edges, so that its maximum eigenvalue falls into the appropriate subinterval. [ABSTRACT FROM AUTHOR]

The immunities of computers against malware are actually heterogeneous depending upon the level of secure protection, which is largely determined by the security awareness of users. To understand the effects this can have on the propagation of malicious software, we herein develop a new compartmental model that takes into account heterogeneous immunization of the computer. In terms of protection levels, the traditional susceptible compartment is newly separated into two sub-compartments, weakly-protected and strongly-protected. Besides, our model includes two assumptions: a computer immediately possesses infectivity once it is infected by malware, and weakly-protected susceptible computers have a higher infection rate than strongly-protected susceptible computers. Appropriate Lyapunov functions are introduced to fully analyze the qualitative properties of this model. Specifically, it is proved that the malware-free equilibrium is globally asymptotically stable if the threshold is below unit, whereas the malware equilibrium is globally asymptotically stable if the threshold is above unit. Furthermore, the sensitivity of each parameter on the model’s threshold is also analyzed. Through numerical simulations, a collection of effective measures for controlling malware spread is proposed, such as keeping as many systems strongly-protected as possible. These findings suggest that the security awareness of users should be taken both in the interpretation of malware parameters, as well as in the prediction of the evolution of future malware outbreaks. [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]

As the phenomenon of knowledge overload becomes more and more obvious, the automatic summarization technology still needs to break through the bottleneck in order to improve the application value and expand the scope of the application. Traditional training paradigms for extractive summarization systems suffer from the inconsistency in training and evaluation. In this paper, we propose an innovative and interpretable contrastive learning based framework for extractive summarization called DCDSum , which comprises a D iverse Oracle evaluator, a C ontrastive learning extractor, and a D ynamic Top-k selector. Different from previous models that consider the extractive summarization task as a sequence labeling problem, our contrastive learning extractor treats it as a sentence reranking problem and introduces contrastive loss to achieve it, which can bridge the gap between objective function and evaluation metrics. The experimental results demonstrate the outstanding performance of our approach on the CNN/DailyMail, XSum, and PubMed datasets, achieving highly competitive results. In particular, our method achieves ROUGE-1 of 44.65, ROUGE-2 of 21.32, and ROUGE-L of 40.87 on the CNN/DailyMail dataset. The outcomes across various evaluation metrics substantiate that the Diverse Oracle extraction algorithm adeptly captures a broader array of sentences with reduced redundancy, consequently enhancing the interpretability of the DCDSum framework. [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]

The output and grade of liquid potash minerals in Qarhan Salt Lake are decreasing year by year, which has become the main problem restricting the sustainable production of potassium fertilizer. The exploitation and utilization of low-grade solid potash ore, which is in the strata of the Qarhan Salt Lake, represents the fundamental framework for the sustainable development of Qarhan Salt Lake's potash fertilizer. PHREEQC is a simulation software for hydrogeochemistry. In this paper, PHREEQC was applied to simulate temperature, pH value and solvent chemical characteristics which affect the dissolution process of low-grade solid potash minerals. The simulation results indicate that the optimum temperature for ore dissolution is around 25 °C, because, around this temperature, the dissolving ability of solvents to low-grade solid potash minerals is enhanced, while the dissolving ability to halite remains basically unchanged, which is conducive to selective dissolution of low-grade solid potash. It is recommended the temperature is between 20 and 30 ℃. The simulation results show that, when the pH value of solvents is more than 9, although it is advantageous to selective dissolution of low-grade solid potash minerals, the solvent becomes strong alkali solution, which will cause environmental pollution and seriously corrode materials and equipment in actual production, so it is recommended the pH value of the solvent is adjusted between 6 and 8. The simulation results show that, when the values of K+, Na+, Mg2+, Ca2+, Cl− and SO42− in the solvent are 0.1%, 2.9%, 3.77%, 0.05%, 15.72% and 0.13% respectively, the solubility of low-grade solid potash ores is stronger, which is more conducive to selective ore dissolution. It is suggested that in actual production, the chemical composition of solvents prepared with old brine and fresh water should be as close as possible to the above chemical composition characteristics. [ABSTRACT FROM AUTHOR]

This paper studies the reachability realization problem of discrete-time switched linear systems. A new constructive approach is developed to design switching sequence such that the reachable subspace is realized. Compared with the existing results, the length of the designed switching sequence is smaller and the proposed algorithm has fewer calculations. One numerical example is presented to illustrate the effectiveness of the obtained results. [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]