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As an actuator control element of the electrohydraulic system in aerospace, airplanes, and other equipment, the spool valve is prone to the "hydraulic lock" problem, which may cause major accidents of these electrohydraulic systems. The grooves engraved on the spool can effectively eliminate this problem by migrating the uneven pressure distribution in the clearance film between the sleeve and the spool. The effect of migrating uneven pressure distribution depends on the groove parameters. This paper proposed an accurate mathematical model with rectangular grooves to investigate the effect. Unlike previous mathematical models based on the Reynolds equation, the proposed model is based on the Navier–Stokes equation, which is more valid in the range where the clearance film thickness is much less than the groove depth. Meanwhile, the mathematical model takes the distributions, width, depth, and the number of grooves into consideration. Then, the proposed mathematical model was used to investigate the effects of mitigating the uneven pressure distribution under various parameters of grooves. To verify the accuracy of the mathematical model, the volume flow leakage in the clearance film obtained by the proposed model and the Reynolds equation, respectively, is compared with that obtained by the experimental test. The comparison results indicate that the results obtained by the Reynolds equation could reach a maximum of 14.75% different from the experimental results, while the results obtained by the NS equation are only 5.57% different under the same conditions, implying that the mathematical model derived from the NS equation is more accurate. [ABSTRACT FROM AUTHOR]

In the Fundamental Review of the Trading Book (FRTB), the latest regulation for minimum capital market risk requirements, one of the major changes, is replacing the Incremental Risk Charge (IRC) with the Default Risk Charge (DRC). The DRC measures only the default and does not consider the migration rating risk. The second new change in this approach was that the DRC now includes equity assets, contrary to the IRC. This paper studies DRC modeling under the Internal Model Approach (IMA) and the regulator conditions that every DRC component must respect. The FRTB presents the DRC measurement as Value at Risk (VaR) over a one-year horizon, with the quantile equal to 99.9%. We use multifactor adjustment to measure the DRC and compare it with the Monte Carlo Model to understand how the approach fits. We then define concentration in the DRC and propose two methods to quantify the concentration risk: the Ad Hoc and Add-On methods. Finally, we study the behavior of the DRC with respect to the concentration risk. [ABSTRACT FROM AUTHOR]

Migrants face several unmet health needs due to the inability of the healthcare system to address their healthcare challenges. As a result, they adopt coping strategies to overcome their healthcare needs. Consequences can include infrequent but severe adverse reactions, dangerous drug interactions, incorrect dosage etc. Little is known in Ghana about the role played by cultural and linguistic barriers in shaping migrants' access to formal healthcare and the coping mechanisms adopted by these migrants to overcome their healthcare challenges. Surprisingly, most of the studies that have been conducted have focused on financial barriers to care accessibility. This presents a loss opportunity for any health programme aimed at addressing this inequity. Thus, the purpose of this paper is to fill this gap by exploring the challenges of healthcare accessibility and coping strategies adopted by migrants to overcome their healthcare needs in the informal urban settlement of Madina, in the Greater Accra Region. The author employed a narrative type of qualitative research design. A purposive and then snowball sampling technique were used to select 20 participants to participate in the study after saturation was reached. Twelve in‐depth interviews (IDIs) and six key informants' interviews (KIIs), as well as two focus group discussions (FGDs), were conducted. The study is consistent with the ecological model, which posits that health is determined by influences at multiple levels. The author found linguistic, cultural, stigmatisation and financial challenges as the main barriers to healthcare accessibility among the migrants. As a result, self‐medication and the use of lay health personnel for addressing healthcare needs were more pronounced. The study also found other means of survival that posed a health risk to the migrants. Based on this, it was recommended that healthcare systems take into account the healthcare needs of migrants who are people with culturally and linguistically diverse backgrounds. [ABSTRACT FROM AUTHOR]

In this paper, a mathematical fractional order Hepatitis C virus (HCV) spread model is presented for an analytical and numerical study. The model is a fractional order extension of the classical model. The paper includes the existence, singularity, Hyers-Ulam stability, and numerical solutions. Our numerical results are based on the Lagrange polynomial interpolation. We observe that the model of fractional order has the same behavior of the solutions as the integer order existing model. [ABSTRACT FROM AUTHOR]

This paper addresses a first numerical simulation to the nonlinear dynamic system of equations that describes the prey-predator model at the predator mating period. Some male species accompany the females during the mating period. In this case, both male and female feed on the same prey. The presented work shows the numerical solution for this specific case of the prey-predator mathematical model via an exponential time differencing method. In addition, the paper provides the biological implication of the solution. [ABSTRACT FROM AUTHOR]

From the perspective of financial constraint, this paper constructs a mathematical model to analyze the impact of digital financial development on firm exit probability. The relationship between digital finance and firm exit was tested empirically based on the industrial firm data in 2011–2013. The results show that digital financial development significantly suppresses firm exit probability. Mechanism analysis suggests that digital financial development can ease the information asymmetry of the credit market, facilitate the credit acquisition of firms, and alleviate the constraint on corporate financing, thereby reducing the probability of firm exit. This paper provides the theoretical basis and empirical evidence for controlling firm exit from the angle of digital finance development. [ABSTRACT FROM AUTHOR]

Physical monitoring and analysis are of great significance to improve national physical fitness. The main work of this paper is that the physical health level of college students is studied and analysed by using a statistical model and mathematical model. According to the characteristics of the collected data, different mathematical models are established. Firstly, the grey correlation model is used to analyse the correlation between pull-up and other physical fitness indexes. Then, based on the classification of college students and the influence and flow law of interclass crowd, a differential equation system is established based on the LMC model. By analysing the existence and stability of the equilibrium point of the system, as well as the possible folding bifurcation and backward bifurcation at the equilibrium point, this paper makes qualitative and quantitative research on the trend of college students' physical exercise on campus. [ABSTRACT FROM AUTHOR]

The design of an efficient DC-DC converter depends critically on its suitable control. In this paper, a new simplified output tracking control strategy for a DC-DC three-level boost converter is presented. The proposed strategy is characterized by its good tracking performances, its simplicity of design, and the stability that is ensured over the entire operating range. Thanks to (i) the adopted Takagi–Sugeno (TS) fuzzy approach; (ii) the small-signal model derived under the large domain of operating conditions, and (iii) the proportional-integral (PI) controllers' merit. After introducing the three-level boost converter topology, the operating principles and mathematical modeling are addressed. Then, the proposed output control strategy is developed based on the PI control and the TS fuzzy approximation. A controller ensuring the capacitor voltages balancing has been also introduced in this paper. Experimental results using dSPACE (DS1104) and a laboratory prototype of three-level boost converter demonstrate the flexibility of the proposed controller, its reference tracking capability, and its ability to satisfy the performance specification over the whole operating range of the system. [ABSTRACT FROM AUTHOR]

Summary: The ionic liquid compressor is regarded as the most promising compression technology for the hydrogen refuelling station due to the combined application of ionic liquid and the hydraulic driving system. However, the design, mathematical and experimental investigations of the ionic compressor are still absent from the open literature. This paper proposed a new structure design and the design methodology of the ionic liquid compressor. The mathematical modelling considering the valve dynamics was provided for simulating the thermodynamic process, which was verified by the experimental data. The results showed that the delayed closing of the discharge valve would take place due to a high or low stiffness of the valve. The increase in the stiffness alleviated the rebound issue of the suction valve. An increase in the stroke to diameter ratio could solve the rebound issue of the discharge valve. A low or high trajectory coefficient would cause an intense rebound during the closing procedure of the discharge valve. The designed results of the main parameters of the compressor based on the simulation were the suction valve stiffness of 100 N/m, the discharge valve stiffness of 500 N/m, the stroke to diameter ratio of 1.0, and the trajectory coefficient of 0.125 under the given design condition. [ABSTRACT FROM AUTHOR]

Ferroelectric negative capacitance materials have now been proposed for lowering electronics energy dissipation beyond basic limitations. In this paper, we presented the analysis on the performance of negative capacitance (NC) FinFET in comparison with conventional gate dielectrics by using a separation of variables approach, which is an optimal quasi-3D mathematical model. The result has been signified steeper surface potential (ψ), lower threshold voltage (Vth), 1.2 mA of on-state current (Ion), and enhanced immunity of negative capacitance FinFET against short channel effects (SCE's) like 35.3 mV/V of drain-induced barrier lowering (DIBL), 60 mV/dec of subthreshold swing (SS) along with smallest off state current (Ioff) among another conventional gate dielectric. Hence, NC FinFET can be a potential candidate for low power and high-performance device. [ABSTRACT FROM AUTHOR]

The fractured zone in the overlying strata of a coal mine goaf is vital for effective gas drainage. The development height of the fractured zone is lied on the "saddle type" theory and calculated by empirical formula, while the horizontal range is dependent on the caving theory of the "O" circle. However, the height of the fracture zone obtained using the above method is usually too large, and only the horizontal boundary of the fracture zone is defined. Besides, the fracture development degree in different regions is not described. To accurately determine the stable development area of the fractured zone and locate the gas migration channel as well as gas enrichment horizon, in this paper, a geometric and mathematical model for gas extraction in the fractured zone is established based on common high-level drilling. Then, a method of investigating the parameters of the directional high-level drilling in the roof is proposed, and a solving means is provided. Taking Wanfeng Coal Mine as an engineering background, the reasonable parameters of the common high-level drilling were investigated, and the effect was verified using the directional high-level drilling in the roof of an adjacent working face. The results show that the stable extraction volumes of the two directional drilling holes is 1~1.8 m3/min and 0.6~1 m3/min, respectively, which exceeds the optimal extraction volumes of the ordinary drilling holes. The new method of determining the stable development area of the fractured zone is significant for improving the gas drainage effect of the high-level drill holes in the roof. [ABSTRACT FROM AUTHOR]

Printed circuit board (PCB) orthogonal packing problems derive from the massive circuit board production process in the electronic industry. In the early stage, it mainly relied on human experiences to make decisions on how to make the most of each sheet while meeting customers' orders. Up till now, researchers in enterprises and academic circles are still trying to explore effective mathematical models and feasible optimization methods. In most cases, what PCB companies generally face is the orthogonal layout decision, which considers positioning each rectangle PCB piece (PCB-P) on a rectangle sheet board (panel) in an ideal way so that each panel has the minimal remains with the most PCB-Ps. In this paper, multi-round gradual packing methods (MGPMs) are proposed based on the idea of combinatorial optimization and dynamic programming. MGPMs include the depth priority-based method (MGPM-DP) and breadth priority-based branch-and-prune method (MGPM-BC). The former has the advantage of finding better solutions, while the latter has the advantage of consuming short computational time. Through extensive computational tests on real data from a PCB production enterprise in China, both MGPM-DP and MGPM-BC have achieved noticeable and satisfactory results compared with the simplex method, dynamic programming method, and a widely used industrial software (Yuanbo) in China. [ABSTRACT FROM AUTHOR]

In order to solve the problem of resource ecological compensation, this paper proposed a model of resource ecological compensation mechanism based on a rural leisure sports environment. The model is carried out in many places in China. The survey data involves 31 provinces, 10 years, and 43 indicators, with a total of 43 × 10 × 31 = 13,330 data. The preliminary basis of mechanism construction is summarized from four aspects. Finally, make full use of modern information technology to improve the network platform of the compensation mechanism, promote the efficient allocation and comprehensive utilization of ecotourism resources, and lay a solid foundation for establishing a reasonable and perfect resource ecological compensation mechanism and ensuring the long-term and stable operation of the mechanism. Through the experiment, it is found that the timely and effective publication of information can eliminate the inner estrangement between the two sides, so as to make the behavior of both sides more rational. A special information feedback department is established to deal with the opinions put forward by all compensation parties in tourism development, extract effective information, summarize and publish reasonable guidance information, and guide the compensation of both sides to an ideal balance through the feedback of this information. The effectiveness of the experiment is verified. [ABSTRACT FROM AUTHOR]

Smart grids, which possess flexibility, cleanliness, safety, economy, and friendliness, have drawn a lot of attention from all over the world in an era of rapid social and economic development, power technology change, and energy and environmental constraints. However, there are still issues with the design, installation, and operation of smart substations, such as insufficient LAN integration, difficulty quantifying network performance, and inability to keep track of communication. The basic meaning and key technologies of substation communication standards are used as the research object in this paper, and the basic attributes of substation data flow, such as source, type, and function, are qualitatively analyzed. The mathematical model that is most closely fitted is 2.8% more effective. The research object is the topology of the process bus. Through the comparison of various solutions, including star topology, ring topology, bus topology, and mesh topology, the advantages and disadvantages of each topology networking scheme are revealed along with the particular functional requirements of the substation process layer. Further discussion is given to the crucial topology-related technologies of network congestion and flow control. [ABSTRACT FROM AUTHOR]

In this paper, a robust tracking control strategy based on the dynamic feedback linearization method is proposed for the nonlinear and highly coupled dynamic characteristics of coaxial unmanned helicopter. The mathematical model of the coaxial unmanned helicopter is determined by fault analysis. Then the high-order state system is dynamically feedback linearized by extending the state variables, and the dynamic characteristics of the zeros are analyzed according to the expected tracking characteristics of the inner loop. The pole placement of the subsystem realizes robust monitoring of height and position commands by designing robust compensators. On this basis, an outer loop proportional derivative controller is designed for the horizontal positioning subsystem to realize position tracking. Loop tracking simulation ensures the good separation characteristics of feedback linearization method, and trajectory tracking simulation under fault conditions ensures the control ability and durability of the designed controller. [ABSTRACT FROM AUTHOR]

Reservoir simulation is critical to the design of reservoir development plan and has been extensively used. However, it is challengeable for to simulate the production process for fractured reservoirs, because of the fracture geometry and the fracture deformation. Specifically, three problems need to be solved. First, there is a lack of mathematical models that can predict the fracture deformation with acceptable precision. Second, the fracture deformation is stress-dependent; therefore, a geocoupled equation should be used to quantify the stress change, but the solution is extremely expensive. Third, the fracture geometries pose great challenges to traditional gridding techniques. This paper proposes a new geocoupling simulation method that is capable of modeling the complex fracture geometry as well as the fracture mechanical behavior. The geomechanical effects and the reservoir production performance are modeled through an implicit geocoupled model, which is developed based on the poro-mechanics theory. The fixed stress strategy is used to solve the geocoupled equations. Moreover, a comprehensive fracture modeling method is proposed, in terms of the fracture deformation model and the fracture gridding technique to model the fracture effects. Ultimately, this method is used to analyze two field-scale cases. The results demonstrate that this method exhibits good practicability and has practical significance for fractured reservoir development. [ABSTRACT FROM AUTHOR]

Inverse kinematics of robots is a critical topic in the robotics field. Although there are conventional ways of solving inverse kinematics, soft computing is an important technology that has lately gained prominence due to its ability to reduce the complexity of the inverse kinematics problem. This paper presents an inverse kinematics solution using multiple adaptive neuro-fuzzy inference systems (MANFIS). Different models were established by employing various methods of identification. Subtractive Clustering (SCM), Fuzzy C-Means Clustering (FCM), and Grid Partitioning (GP) are the three methods used in this study. This work is being carried out on a 5-DOF articulated robot arm, which is commonly used in industry. A mathematical model is built based on the Denavit-Hartenberg (DH) approach. Following confirmation that the kinematic findings of the mathematical model match the actual observed values of the robot arm, two types of data sets are generated: a random data set and a systematic data set based on a trajectory. The data sets are then utilized to train and evaluate ANFIS models and choose the optimal models to develop MANFIS model. Thus, the prediction and experimental data are compared to assess the performance of the MANFIS model. [ABSTRACT FROM AUTHOR]

SARS-CoV-2 is a strain of the large coronavirus family that has led to COVID-19 disease. The virus has been one of the deadliest known viruses in the world to date. Rapid mutations and the creation of new strains cause researchers to focus on the dynamic behaviors of the virus and to analyze it accurately through clinical research and mathematical models. In this paper, from the point of view of mathematical modeling, we intend to focus on the dynamic behavior of the system and examine its analytical and numerical aspects in two different structures. In other words, by recalling newly formulated hybrid fractional-fractal operators, we present a fractal-fractional probability-based model of SARS-CoV-2 virus for the first time and extract its equivalent compact fractal-fractional IVP to investigate its existence and stability criteria. A type of special admissible contractions will help us in this regard. Moreover, based on the source data, we simulate our system according to algorithms derived by Adams-Bashforth method and explain the effects of variation of the dimension of fractal and fractional order on dynamics of solutions. Finally, we transform our fractal-fractional model into a Caputo probability-based model of SARS-CoV-2 to derive solutions via the operational matrix method under Taylor's basis. The numerical simulations show close behaviors for both of models. [ABSTRACT FROM AUTHOR]

Many genetic centers are developing innovative delivery models for services to address the growing need for access to genetics in the setting of a limited genetics‐certified workforce. In the literature review, alternative service delivery models—including telehealth and genetic counselor involvement with nongenetics specialty providers—aim to increase efficiency, patient access, and provider satisfaction. This paper outlines a traditional model of pediatric care, with a workflow involving a geneticist and genetic counselor, from preclinic to follow‐up. We then present a workflow model of a collaborative team consisting of a genetic counselor and nurse practitioner in condition‐specific pediatric clinics. We break down factors influencing the successful implementation of this model, including patient selection, pre‐established and adaptive clinic goals, and differentiation of roles of the providers. Potential barriers to generalization and the ongoing success of this clinic model include provider interest in genetics and the necessity for careful triaging by clinicians. Formalized analysis of these clinics has not been performed, though at the presented institution, this clinic model is recognized as an effective way to decrease wait times for patients referred for specific indications and creates an environment that allows providers to specialize, increasing their expertize and confidence in particular genetic areas. [ABSTRACT FROM AUTHOR]

The aim of this paper is to model the dynamics of the human papillomavirus (HPV) in cervical epithelial cells. We developed a mathematical model of the epithelial cellular dynamics of the stratified epithelium of three (basale, intermedium, and corneum) stratums that is based on three ordinary differential equations. We determine the biological condition for the existence of the epithelial cell homeostasis equilibrium, and we obtain the necessary and sufficient conditions for its global stability using the method of Lyapunov functions and a theorem on limiting systems. We have also developed a mathematical model based on seven ordinary differential equations that describes the dynamics of HPV infection. We calculated the basic reproductive number ( R 0 ) of the infection using the next-generation operator method. We determine the existence and the local stability of the equilibrium point of the cellular homeostasis of the epithelium. We then give a sufficient condition for the global asymptotic stability of the epithelial cell homeostasis equilibrium using the Lyapunov function method. We proved that this equilibrium point is nonhyperbolic when R 0 = 1 and that in this case, the system presents a forward bifurcation, which shows the existence of an infected equilibrium point when R 0 > 1. We also study the solutions numerically (i.e., viral kinetic in silico) when R 0 > 1. Finally, local sensitivity index was calculated to assess the influence of different parameters on basic reproductive number. Our model reproduces the transient, acute, latent, and chronic infections that have been reported in studies of the natural history of HPV. [ABSTRACT FROM AUTHOR]

It is often said that mathematical modeling is an implementation of mathematics in real-world problems with the aim of better understanding them, so we can say that mathematical modeling is linked to the solution of problems. Some of the essential principles and procedures of mathematical modeling are discussed using formulas and equations. We investigate the stability and convergence characteristics and demonstrate the suitability of different mathematical methods in a set of numerical examples. The described methods in our paper are the best choices for the simulation of linear phenomena and are more efficient for use with high-order spatial discretization. We emphasized the importance of mathematical modeling technologies used in computational tools. Our study shows that these new methods are more stable with lower errors. [ABSTRACT FROM AUTHOR]

The nanoindentation technique is employed to characterize the behaviors of biomaterials. Nevertheless, there is a lack of development of a miniaturized precise positioner for in situ nanoindentation. Besides, modeling behaviors of the positioner are restricted due to its complex kinematic characteristics. Therefore, this paper proposes a novel compliant two degrees of freedom (dof) stage for positioning a biomaterial sample in in situ nanoindentation. In addition, a new modeling and dimensional optimization synthesis method of the stage is developed. The proposed effective methodology is developed based on a kinetostatic analysis-based calculation method, the Lagrange approach, and a neural network algorithm. With an increased advance in artificial intelligence, a neural network algorithm is proposed to extend the applicability of artificial neural networks in optimizing the parameters of the stage. First, the 2-dof stage is built via a combination of an eight-lever displacement amplifier and a symmetric parallelogram mechanism. Second, a chain of mathematical equations of the 2-dof stage is constructed using a kinetostatic analysis-based method to calculate the ratio of displacement amplification and the input stiffness of the 2-dof stage. Then, the Lagrange method is utilized to formulate the dynamic equation of the 2-dof stage. Finally, a neural network algorithm is adopted to maximize the natural first frequency of the proposed stage. The optimal results determined that the frequency of the stage can achieve a high value of 112.0995 Hz. Besides, the formed mathematical models were relatively precise by comprising the simulation verifications. [ABSTRACT FROM AUTHOR]

The state space method of gear train analysis and the unified mathematical model of state space based gear train analysis are proposed in this paper. Firstly, the concept of basic gear train unit is defined, and the state transformation equation of basic gear train unit is established, which is applied to express the transformation rule of the basic gear train unit and the adjacency relationship between the units. Then, the gear train state space is formed based on the dual vectors including input state eigenvector and output state eigenvector, which describe the state characteristics of the gear train unit. The state space is established based on the mapping relationship among the input-output dual vectors, the state transformation matrix, and the gear train unit. Then the dual vector operation laws and mathematical operation methods in gear train state space are generated. Therefrom, a unified mathematical model based on the kinematic, statics, and structural characteristics of the gear train in the state space is established. Finally, the digital identification and automatic analysis of any complex gear train is realized. The fast comparison and analysis of a large number of gear train schemes is achievable in the scheme design stage. [ABSTRACT FROM AUTHOR]

The green environment is the need of the hour. There are many techniques opted by the agriculture experts for Hedera nepalensis cutting propagation. In order to simulate the propagation pattern of Hedera nepalensis cuttings more vividly, the simulation method of Hedera nepalensis cuttings propagation based on fractal theory has been studied in this paper for promoting green environment. The rule of L-system to generate to Hedera nepalensis graphics is elaborated in detail. The composition of generators is represented by strings, and Hedera epalensis fractal images are generated repeatedly by recursive algorithm. Combining BSP technology (Binary Space Partitioning Tree) with L-system, the simulation model of Hedera nepalensis cutting propagation is designed. The mechanism and morphological difference of real Hedera nepalensis cutting propagation are investigated in detail. The different Hedera nepalensis organs are distinguished by static simulation and the mathematical model is established. With the help of GDI+, random functions are flexibly used in programming control to simulate the process of Hedera nepalensis cutting propagation. By determining the growth proportion coefficient of each organ and the growth coefficient of control parameters, the image of Hedera nepalensis cutting reproduction is generated continuously from the dynamic control parameters and the dynamic process of Hedera nepalensis cutting reproduction is simulated. The simulation results show that the simulation error of this method is less than 0.8%. The simulation process is simple and efficient, and the simulation results are vivid and viable to suggest newer solution for Hedera nepalensis cutting propagation to protect the environment. [ABSTRACT FROM AUTHOR]

Attribute encryption is an effective one to many network communication technologies, which supports flexible access control strategies and is very suitable for fine-grained access control in large-scale information systems. In order to improve the attributes of static data, encryption technology can provide a reliable technical guarantee for network security. This paper presents a mathematical modeling method of static data attribute encryption based on big data technology. The big data redundancy elimination algorithm based on similarity calculation is analyzed. By using static data attribute encryption based on big data technology, the length of encrypted data packets will not increase, and partial redundancy of fragments can be eliminated, which can greatly improve the efficiency of the system. The attribute-based encryption mechanism uses attributes as public keys, and the decryption user is a group; so, the encryption efficiency is very high. It can realize efficient encryption and decryption, as well as flexible access control based on user attributes. This scheme can reflect the importance of attributes; so, it is more practical. [ABSTRACT FROM AUTHOR]

In this paper, a decision-making system for precision marketing is presented to deal with real-world problems based on real e-business data collected in a company in Beijing. During the data preprocessing, the authors conducted a cleaning course to make sure the data to be analyzed in the latter part of the paper were credential. Based on the processed data, the authors analyzed consumer purchasing behaviors using three classic recommendation algorithms and made a performance comparison of the three algorithms. At the end of this paper, the authors proposed a series of precision marketing strategies which had been adopted by the data source company and had been proved to be effective in improving the performance. [ABSTRACT FROM AUTHOR]

Tool design is one of the key factors that restrict the development of gear skiving technology since the design principle does not correspond to the cutting principle. The existing skiving tool cannot achieve ideal machining accuracy and reasonable cutting angles. In view of this, some research has been done in this paper. Firstly, the skiving principle is investigated essentially according to the skiving motions. Then, the principle of tool design is analyzed based on the theory of conjugate surface, and a new tool design method is proposed to match the skiving principle. For this, all the skiving patterns for various kinds of workpieces are enumerated and summarized to abstract a normalized skiving model. Based on this, the mathematical model of the conjugate surface is then derived to lay the foundation for tool design. Then, the design methods of cutting edge, rake face, and flank face are proposed. An example is presented at last, and the cutting simulation is conducted. The result proves that the proposed methods are correct and valid. The theoretical research in this paper could promote the improvement of skiving tools. [ABSTRACT FROM AUTHOR]

With the advent of the era of big data, data mining has become one of the key technologies in the field of research and business. In order to improve the efficiency of data mining, this paper studies data mining based on the intelligent recommendation system. Firstly, this paper makes mathematical modeling of the intelligent recommendation system based on association rules. After analyzing the requirements of the intelligent recommendation system, Java 2 Platform, Enterprise Edition, technology is used to divide the system architecture into the presentation layer, business logic layer, and data layer. Recommendation module is divided into three substages: data representation, model learning, and recommendation engine. Then, the fuzzy clustering algorithm is used to optimize the system. After the system is built, the performance of the system is evaluated, and the evaluation indexes include accuracy, coverage, and response time. Finally, the system is put into a trial operation of an e-commerce platform. The click-through rate and purchase conversion rate of recommended products before and after the operation are compared, and a questionnaire survey is randomly launched to the platform users to analyze the user satisfaction. The experimental data show that the MAE of this system is the lowest, maintained at about 0.73, and its accuracy is the highest; before the recommended threshold exceeds 0.5, the average coverage rate of this system is the highest: 0.75; in Q1–Q5 subsets, the shortest response time of the system is 0.2 s. Before and after the operation of the system, the average click-through rate increased by 11.04%, and the average purchase rate increased by 9.35%. Among the 1216 users, 43% of the users were satisfied with 4 and 9% with 1. This shows that the system algorithm convergence speed is fast; it can recommend products more in line with user needs and interests and promote higher click-through rate and purchase rate, but user satisfaction can be further improved. [ABSTRACT FROM AUTHOR]

The main contribution of this paper is the proposal of a recent hysteresis dynamic model which is successfully employed within a posited signal modulator. The modulation of signals is a commonly required stage in many engineering applications, such as telecommunications, power electronics, and control, among others. In this paper, the effectiveness of a signal modulator based on the well-known Delta modulator when it contains a dynamic hysteresis system within its main structure is presented. To do that, it is resorted to an application of the granted Hysteresis-Delta Modulator. This application consists of including the modulator within an adaptive scheme, since it is well known that the persistent excitation condition is required, for instance, in parameter estimation tasks. Hence, the main functional property of the modulator with hysteresis is its ability of producing a modulated signal with uniform high-frequency content even when its input is not a permanent persistent excitation signal. To highlight the main contribution of this paper, a numerical experiment of a parameter estimation system is developed to compare the performance of the modulator with the proposed hysteresis model and two other previously reported hysteresis systems. That is, three different scenarios have been tested in the parameter estimation of a nonminimum phase system. Finally, the numerical experiments confirm that the proposed hysteresis model along with the modulator provides the best performance as expected. [ABSTRACT FROM AUTHOR]

In this paper, we construct and analyze a theoretical, deterministic 5 D mathematical model of Limnothrissa miodon with nutrients, phytoplankton, zooplankton, and Hydrocynus vittatus predation. Local stability analysis results agree with the numerical simulations in that the coexistence equilibrium is locally stable provided that certain conditions are satisfied. The coexistence equilibrium is globally stable if certain conditions are met. Existence, stability, and direction of Hopf bifurcations are derived for some parameters. Bifurcation analysis shows that the model undergoes Hopf bifurcation at the coexistence point for the zooplankton growth rate with periodic doubling leading to chaos. [ABSTRACT FROM AUTHOR]

In order to find a chaotic trajectory sequence with strong global optimization ability to help the genetic selection of direction after the reversal of chemotaxis, an improved genetic algorithm based on chaos optimization is proposed by combining the characteristics of chaotic motion with the improved genetic algorithm. The optimal coverage problem in sensor networks can carry out fine optimization search on local areas. The results show that the overall trend of fitness and optimization efficiency is relatively stable. The optimization efficiency will be gradually improved with the continuous progress of time and genetics, and the error analysis will be reduced. This will greatly improve the impact of various adverse factors in the optimization process. In addition, the change rate of fitness is basically kept at a high change rate, which also reflects that the basic framework of the model is very excellent, and the whole algorithm structure and data processing are improved by 54%. The improved genetic algorithm proposed in this paper is used to adjust and optimize the controller parameters. When the uncertain parameters change greatly, the control system still has good control quality and strong robustness. [ABSTRACT FROM AUTHOR]

Cervical cancer is one of the main causes of cancer death all over the world. Most diseases such as cervical epithelial atypical hyperplasia and invasive cervical cancer are closely related to the continuous infection of high-risk types of human papillomavirus. Therefore, the high-risk types of human papillomavirus are the key to the prevention and treatment of cervical cancer. With the accumulation of high-throughput and clinical data, the use of systematic and quantitative methods for mathematical modeling and computational prediction has become more and more important. This paper summarizes the mathematical models and prediction methods of the risk types of human papillomavirus, especially around the key steps such as feature extraction, feature selection, and prediction algorithms. We summarized and discussed the advantages and disadvantages of existing algorithms, which provides a theoretical basis for follow-up research. [ABSTRACT FROM AUTHOR]

The cold and high altitude Tibetan area (hereinafter referred to as Tibetan area) is a special geographical area in western China. Whether the local economic development and EE (ecological environment) are coordinated or not directly affects the sustained and healthy economic and social development of the whole Tibetan area. Firstly, this paper discusses the relationship between economic growth and EE on the basis of existing related theoretical research. Then, 15 indicators of economic system and environmental system were selected, and the coupling degree model and coupling coordination degree model were constructed to quantitatively analyze the dynamic model of regional economic and EE coupling and coordinated development in Tibetan areas from 2010 to 2020. The research found that in the past 11 years, the comprehensive index of EE of four regions in Tibetan areas has changed from 0.5 to 0.6, and the comprehensive index of the economy of four regions in Tibetan areas has changed from 0.51 to 0.74. On the whole, the coordination degree and coordinated development degree of green development in Tibetan areas have changed at the same time compared with the years, and since 2016, both of them have had the same trend and both of them are beginning to develop in a good direction. Since 2017, the economic development has been relatively advanced, while the EE has lagged behind, showing a fluctuating state, while the level of coordinated development has been continuously improved. This study has certain reference value for promoting ecological protection and green development in Tibetan areas. [ABSTRACT FROM AUTHOR]

In this paper, we propose a continuous mathematical model that describes the spread of multistrains COVID-19 virus among humans: susceptible, exposed, infected, quarantined, hospitalized, and recovered individuals. The positivity and boundedness of the system solution are provided in order to get the well posedness of the proposed model. Secondly, three controls are considered in our model to minimize the multistrain spread of the disease, namely, vaccination, security campaigns, social distancing measures, and diagnosis. Furthermore, the optimal control problem and related optimality conditions of the Pontryagin type are discussed with the objective to minimize the number of infected individuals. Finally, numerical simulations are performed in the case of two strains of COVID-19 and with four control strategies. By using the incremental cost-effectiveness ratio (ICER) method, we show that combining vaccination with diagnosis provides the most cost-effective strategy. [ABSTRACT FROM AUTHOR]

With the continuous development and application of data computing in the whole society in the construction of digital campus and intelligent campus of each higher education institution. In the environment of education, universities use these data well, which not only affects the orderly operation of higher education but also will become an inexhaustible power to help higher education promote the reform and innovation of education and teaching system. In this paper, we focus on the teaching operation and students' independent learning by taking students' evaluation data and students' online learning data of Y school as the research objects. We conducted a preliminary analysis and transformation of students' evaluation data of a university, eliminated the abnormal evaluation data by using the improved cosine phase dissimilarity algorithm, standardized the evaluation data by using the normalization method, and used the traditional K -modes algorithm. Based on these three problems, the traditional K -modes algorithm was improved in three aspects, including the determination of the number of clustering families, the determination of the measurement of clustering distances, and the experimental results showed that the improved algorithm was more reasonable and effective. [ABSTRACT FROM AUTHOR]

As the competition between enterprises intensifies, employees have witnessed a decline of psychological health year by year and severe anxiety and depression. To ensure the normal work of employees, it is important to implement psychological occupational therapy intervention (POTI). The previous studies on corporate occupational values focus on the behavioral variables and attitude variables related to occupations. The research paradigm does not suit a specific group of employees. Therefore, this paper explores the individual differences in POTI guided by the realization of occupational values. For a specific group of employees, the correlations of the psychological problems with job attitude, job involvement, and psychological health level were reasoned logically, a theoretical model was established, and the full-model map was plotted to illustrate the influence of the realization of occupational values over POTI. Then, the evaluation data on the psychological intervention effect of 2,800 employees were explored based on multikernel learning, and an individual difference prediction model was constructed through multikernel learning. Finally, the predicted results of different groups of employees were compared, revealing the effectiveness of our algorithm. [ABSTRACT FROM AUTHOR]

The jet pipe servo (JPS) valve is one key component, whose dynamic performance directly influences the aircraft's maneuverability. In this paper, a more accurate mathematical model and a novel multiobjective hierarchical encourage particle swarm optimization genetic algorithm (HEPGA) are proposed to improve the dynamic performance of the jet pipe servo valve. By optimizing the main structure parameters of the jet pipe servo valve, the adjustment and overshoot in the dynamic performance are reduced by 24.28% and 51.39%, respectively, compared with the prototype before optimization. To obtain a more accurate mathematical model, the computational fluid dynamics (CFD) is introduced to modify the analytical model considering the turbulent submerged free jet. Different from conventional numerical simulation, the dynamic mesh technique is used to analyze the flow field distribution by considering the force interaction of various parts of the jet pipe servo valve under actual working condition. Then, the HEPGA with better convergence is utilized because of the conflict of adjustment and overshoot. This proposed hybrid algorithm introduces the concept of staff welfare system to divide the population into elite individuals and excellent individuals of particle swarm optimization and general individuals of genetic algorithm. Meanwhile, the convergency performance of the HEPGA is evaluated through the Rosenbrock function by comparing with other particle swarm genetic hybrid methods. Subsequently, the experimental platform is constructed and the dynamic performance tests are conducted on the prototype after optimization. The experimental results verify the accuracy of the established mathematical model and the significant improvement of dynamic performance of the jet pipe servo valve. [ABSTRACT FROM AUTHOR]

Since the outbreak of the COVID-19 epidemic, several control strategies have been proposed. The rapid spread of COVID-19 globally, allied with the fact that COVID-19 is a serious threat to people's health and life, motivated many researchers around the world to investigate new methods and techniques to control its spread and offer treatment. Currently, the most effective approach to containing SARS-CoV-2 (COVID-19) and minimizing its impact on education and the economy remains a vaccination control strategy, however. In this paper, a modified version of the susceptible, exposed, infectious, and recovered (SEIR) model using vaccination control with a novel construct of active disturbance rejection control (ADRC) is thus used to generate a proper vaccination control scheme by rejecting those disturbances that might possibly affect the system. For the COVID-19 system, which has a unit relative degree, a new structure for the ADRC has been introduced by embedding the tracking differentiator (TD) in the control unit to obtain an error signal and its derivative. Two further novel nonlinear controllers, the nonlinear PID and a super twisting sliding mode (STC-SM) were also used with the TD to develop a new version of the nonlinear state error feedback (NLSEF), while a new nonlinear extended state observer (NLESO) was introduced to estimate the system state and total disturbance. The final simulation results show that the proposed methods achieve excellent performance compared to conventional active disturbance rejection controls. [ABSTRACT FROM AUTHOR]

Sparrow search algorithm has the problem of redundancy of convergence speed due to its fast convergence speed, and it is easy to fall into local optimum in multimodal environment. To solve the above problem, this paper presents a personalized multipopulation sparrow search algorithm (MPSSA). By introducing multiple population mechanisms to reduce the probability of falling into the local optimum due to single-population search, by using a personalized subpopulation strategy to improve the personalized differences of subpopulations and balance the exploratory ability of algorithm development, then by using weighted center-of-gravity communication strategy to improve the quality of communication between populations, and finally by using dimension by dimension dynamic reverse learning to improve the accuracy of search. The superiority of MPSSA is validated by comparing the benchmark function and CEC2017. Finally, the algorithm solves the problem of poor quality due to the dimension increase of the UAV cooperative track. MPSSA helps the UAV to quickly plan a better and stable track group to ensure the UAV to complete the cooperative task safely and stably. [ABSTRACT FROM AUTHOR]

This paper constructs an evaluation model of occupational competency in rehabilitation therapy and applies it to the improvement of college students' innovative and entrepreneurial competencies. Based on clarifying the connotation of college students' entrepreneurial competency, this study carries out research on the evaluation system of college students' entrepreneurial competency. First, the method of qualitative research is used to conduct in-depth interviews with college students and entrepreneurial mentors to understand the views of these groups on college students' entrepreneurial competency, and the coding of the interview contents is carried out by applying the rooting theory, and finally, a theoretical model of the composition of college students' entrepreneurial competency is derived. The front-line position of talent cultivation is the construction of faculty, because the faculty with high-quality vocational ability is an indispensable prerequisite for the development of universities, and the teaching level of the faculty is the key factor for the effectiveness of teaching to appear. Based on the perspective of role theory, we analyze the problems and reasons for the lack of competency in the role-playing process; integrate the three stages of understanding the role, playing the role, and adjusting the role with the competency model; and propose strategies to improve the competency of youth social workers in the process of playing the role, to help workers accurately understand the role, correctly play the role, and reasonably adjust the role. The curriculum is designed to cultivate the competency of college student nursing positions, which is conducive to improving the professional quality of college student nursing service providers and regulating college student nursing practice so that they can actively respond to problems. This will strengthen the entire teaching faculty and enhance the professional competence of full-time teachers. [ABSTRACT FROM AUTHOR]

At the end of 2019, the world knew the propagation of a new pandemic named COVID-19. This disease harmed the exercises of humankind and changed our way of life. For modeling and studying infectious illness transmission, mathematical models are helpful tools. Thus, in this paper, taking into account the effect of the intensity of the noises, we define a threshold value Π s of the model, which determines the extinction and persistence of the COVID-19 pandemic. We give numerical simulations to illustrate the analytical results. [ABSTRACT FROM AUTHOR]

The main semantic symbol systems for people to express their emotions include natural language and music. The analysis and establishment of semantic association between language and music is helpful to provide more accurate retrieval and recommendation services for text and music. Existing researches mainly focus on the surface symbolic features and association of natural language and music, which limits the performance and interpretability of applications based on semantic association of natural language and music. Emotion is the main meaning of music expression, and the semantic range of text expression includes emotion. In this paper, the semantic features of music are extracted from audio features, and the semantic matching model of audio emotion analysis is constructed to analyze ethnic music audio emotion through feature extraction ability of deep structure. The model is based on the framework of emotional semantic matching technology and realizes the emotional semantic matching of music fragments and words through semantic emotional recognition algorithm. Multiple experiments show that when W = 0.65 , the recognition rate of multichannel fusion model is 88.42%, and the model can reasonably realize audio emotion analysis. When the spatial dimension of music data changes, the classification accuracy reaches the highest when the spatial dimension is 25. Analysing the semantic association of audio promotes the application of folk music in occupational therapy. [ABSTRACT FROM AUTHOR]

Inadequate environmental protection is a problem, and to address it, the efficiency and quality grade of mechanical operations should be improved. A new comprehensive mechanized operation solution is proposed. The position control of a servo motor utilizing a PID (proportional, integral, derivative) controller and soft computing optimization approaches is explored in this paper. The essential technological realization techniques are reviewed and assessed, which serves as a reference for comprehensive mechanization solutions. The simulation model may be used to examine system features and explore control strategy by reflecting the characteristics of the actual system. A PID controller is designed by establishing a mathematical model based on the position servo system. It is verified that the PID control link is added to the pneumatic position servo control system. Through the comparison of the PID control experiment and PID control simulation data, the system can achieve high-precision position control, and the error is less than ±20 mm, meeting the requirements of rust removal and spraying design, and showing that the control system works stably and reliably to achieve high-precision simulation of the pneumatic position servo system. [ABSTRACT FROM AUTHOR]

Not only mathematical statistics, differential equations, and mathematical models were used to analyze and reduce data, but a rough set model is also employed in medical, engineering, and other fields to analyze and reduce them. The goal of this paper is to introduce a minimal structure concept to produce new rough set models and show that it is suitable for analyzing most real-life problems, reduction of attributes, and decision making. We examine the effectiveness of the following method in the problem of electric power generators and decision making. We also offer a comparison of our method and Pawlak's method. Finally, the variable precision model improves the accuracy of decision making. [ABSTRACT FROM AUTHOR]

Aiming at vehicles will produce shocks and vibrations for various reasons in the process of transportation and handling, any shock and vibration that exceeds the regulations would cause damage to the nuclear fuel being transported. In order to monitor and analyze the shock and vibration data scientifically, a monitoring system based on MEMS acceleration sensor technology is developed to measure shocks and vibrations. The measured result involves some noise caused by the sensitivity of the sensor and the electrical noise, and a digital filter mathematical modelling is introduced to reduce noise and improve the measured result accuracy. In order to verify the effectiveness of the device designed in this paper, the device and the high-precision seismic acceleration sensor AC73 are, respectively, used for field tests; the results show that the test precision of the designed device can meet the requirements, and also, the designed shock and vibration monitoring system can record and store the three-axis acceleration, temperature, humidity, pressure, time, and other parameters that exceed the set threshold during nuclear fuel transportation in real time and complete the fuel assembly transportation status assessment and promptly remind the transportation personnel to take safety precautions and treatment measures. Therefore, it can be widely used in the monitoring, recording, and postevent data analysis of the transportation process of important products such as nuclear fuel. [ABSTRACT FROM AUTHOR]

The uncertain data appear in majority of real-world phenomena regarding business, engineering, manufacturing, industries, medical, and other social fields. The neutrosophic sets (NSs), soft sets (SSs), and rough sets (RSs) are distinct mathematical models to deal with different types of uncertainties in data and information. Nowadays, several hybrid models are emerging as their combination or their further generalizations. In this paper, the concept of multineutrosophic fuzzy soft rough sets (MNFSRSs) by combining multineutrosophic fuzzy soft sets (MNSSs) with RSs is presented. Certain eminent features of the proposed structure are investigated. Moreover, a general decision-making (DM) algorithm is described for DM problems to indicate the effectiveness of the presented model. [ABSTRACT FROM AUTHOR]

Because of the particularity of energy being non-renewable, the development of energy-intensive cities must consider its follow-up development issues in advance, especially for newly developed energy-intensive cities like Songyuan in the midwest of Jilin Province. It is necessary to summarize the experience from other energy-intensive cities and recognize the problems existing in its own development, so that the development of the city will not perish due to the exhaustion of energy. At present, the sustainable development of energy-intensive cities is the focus of attention at home and abroad. Energy-intensive cities have made great contributions to the national and regional economy but also paid a considerable price. Making the city continue to prosper and develop steadily without causing the city to decline due to the exhaustion of energy is the main problem facing the country, the government, and experts and scholars. Taking Songyuan City in Northeast China as an example, this paper adopts a combination of breakthroughs from the surface and breakthroughs, supplemented by theoretical analysis and empirical evaluation, and uses mathematical model simulation and expert consultation and decision-making methods. Starting from the theoretical height of man-land harmony and sustainable development, we construct an evaluation model of rural development status in energy-enriched poverty-stricken areas, evaluate the evolution trend of rural development status, and propose leading models and development strategies for rural transformation and development in energy-enriched poverty-stricken areas. It provides theoretical reference and decision-making basis for the sustainable development of rural Songyuan City. [ABSTRACT FROM AUTHOR]

With the rapid development of science and technology and the steady recovery of the economy, rural ecotourism has become the first choice for many residents for tourism and entertainment. As an integral part of urban-rural integration planning, rural ecotourism can play a positive role in promoting the development of the township economy and farmers' entrepreneurship and employment. In recent years, rural ecotourism has been vigorously developed and promoted under the supportive policies and the high attention of local governments. Based on in-depth research on the comprehensive evaluation index system of sustainable development of rural tourism resources at home and abroad, this paper selects 15 3-level indicators from four aspects of management planning, economic development, environmental protection, and social value to evaluate the rural tourism in Huangqiao Town. A fuzzy comprehensive evaluation is carried out on the sustainable development level of resources. The evaluation results show that the comprehensive score of the sustainable development level of rural tourism resources in Huangqiao Town is "good," which indicates that Huangqiao Town pays more attention to the development and utilization of rural tourism resources. [ABSTRACT FROM AUTHOR]

The uncertain data appear in majority of real-world phenomena regarding business, engineering, manufacturing, industries, medical, and other social fields. The neutrosophic sets (NSs), soft sets (SSs), and rough sets (RSs) are distinct mathematical models to deal with different types of uncertainties in data and information. Nowadays, several hybrid models are emerging as their combination or their further generalizations. In this paper, the concept of multineutrosophic fuzzy soft rough sets (MNFSRSs) by combining multineutrosophic fuzzy soft sets (MNSSs) with RSs is presented. Certain eminent features of the proposed structure are investigated. Moreover, a general decision-making (DM) algorithm is described for DM problems to indicate the effectiveness of the presented model. [ABSTRACT FROM AUTHOR]

Because of the particularity of energy being non-renewable, the development of energy-intensive cities must consider its follow-up development issues in advance, especially for newly developed energy-intensive cities like Songyuan in the midwest of Jilin Province. It is necessary to summarize the experience from other energy-intensive cities and recognize the problems existing in its own development, so that the development of the city will not perish due to the exhaustion of energy. At present, the sustainable development of energy-intensive cities is the focus of attention at home and abroad. Energy-intensive cities have made great contributions to the national and regional economy but also paid a considerable price. Making the city continue to prosper and develop steadily without causing the city to decline due to the exhaustion of energy is the main problem facing the country, the government, and experts and scholars. Taking Songyuan City in Northeast China as an example, this paper adopts a combination of breakthroughs from the surface and breakthroughs, supplemented by theoretical analysis and empirical evaluation, and uses mathematical model simulation and expert consultation and decision-making methods. Starting from the theoretical height of man-land harmony and sustainable development, we construct an evaluation model of rural development status in energy-enriched poverty-stricken areas, evaluate the evolution trend of rural development status, and propose leading models and development strategies for rural transformation and development in energy-enriched poverty-stricken areas. It provides theoretical reference and decision-making basis for the sustainable development of rural Songyuan City. [ABSTRACT FROM AUTHOR]