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Computer modeling in Engineering & Sciences 2024年第3期138卷 2973-3012页

作者： Andrew Omame Mujahid Abbas Dumitru Baleanu Department of Mathematics Federal University of TechnologyOwerri460114Nigeria Abdus Salam School of Mathematical Sciences Government College UniversityLahore54000Pakistan Department of Mathematics Government College UniversityLahore54000Pakistan Department of Computer Science and Mathematics Labanese American UniversityBeirutLebanon Institute of Space Sciences Magurele-BucharestRomania Department of Medical Research China Medical University HospitalChina Medical UniversityTaichung40402Taiwan

A patient co-infected with COVID-19 and viral hepatitis B can be atmore risk of severe complications than the one infected with a single *** study develops a comprehensive stochastic model to assess the epidemiological impact of vaccine booster doses on the co-dynamics of viral hepatitis B and *** model is fitted to real COVID-19 data from *** proposed model incorporates logistic growth and saturated incidence *** analyses using the tools of stochastic calculus,are performed to study appropriate conditions for the existence of unique global solutions,stationary distribution in the sense of ergodicity and disease *** stochastic threshold estimated from the data fitting is given by:R_(0)^(S)=*** assessments are implemented to illustrate the impact of double-dose vaccination and saturated incidence functions on the dynamics of both *** effects of stochastic white noise intensities are also highlighted.

关键词： Viral hepatitis B COVID-19 stochastic model extinction ergodicity real data

A modified stochastic model for LS+AR hybrid method and its application in polar motion short-term prediction

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Geodesy and Geodynamics 2024年第1期15卷 100-105页

作者： Fei Ye Yunbin Yuan State Key Laboratory of Geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China BeiDou High-precision Satellite Navigation and Location Service Hunan Engineering Research Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China Hunan Continuously Operating Reference Stations(HNCORS)Data Center Hunan Institute of Geomatics Sciences and TechnologyChangsha 410007China

Short-term(up to 30 days)predictions of Earth Rotation Parameters(ERPs)such as Polar Motion(PM:PMX and PMY)play an essential role in real-time applications related to high-precision reference frame ***,least squares(LS)+auto-regressive(AR)hybrid method is one of the main techniques of PM ***,the weighted LS+AR hybrid method performs well for PM short-term ***,the corresponding covariance information of LS fitting residuals deserves further exploration in the AR *** this study,we have derived a modified stochastic model for the LS+AR hybrid method,namely the weighted LS+weighted AR hybrid *** using the PM data products of IERS EOP 14 C04,the numerical results indicate that for PM short-term forecasting,the proposed weighted LS+weighted AR hybrid method shows an advantage over both the LS+AR hybrid method and the weighted LS+AR hybrid *** to the mean absolute errors(MAEs)of PMX/PMY sho rt-term prediction of the LS+AR hybrid method and the weighted LS+AR hybrid method,the weighted LS+weighted AR hybrid method shows average improvements of 6.61%/12.08%and 0.24%/11.65%,***,for the slopes of the linear regression lines fitted to the errors of each method,the growth of the prediction error of the proposed method is slower than that of the other two methods.

关键词： stochastic model LS+AR Short-term prediction The earth rotation parameter(ERP) Observation model

stochastic model of measles transmission dynamics with double dose vaccination

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Infectious Disease modelling 2020年第1期5卷 478-494页

作者： Getachew Teshome Tilahun Seleshi Demie Alemayehu Eyob Haramaya University Department of MathematicsHaramayaEthiopia

In this paper we developed a stochastic model of measles transmission dynamics with double dose *** total population in this model was sub-divided in to five compartments,namely Susceptible SetT,Infected IetT;Vaccinated first dose V1etT;Vaccinated second dose V2etT and Recovered RetT:First the model was developed by deterministic approach and then transformed into stochastic one,which is known to play a significant role by providing additional degree of realism compared to the deterministic *** analysis of the model was done in both *** qualitative behavior of the model,like conditions for positivity of solutions,invariant region of the solution,the existence of equilibrium points of the model and their stability,and also sensitivity analysis of the model were *** showed that in both deterministic and stochastic cases if the basic reproduction number is less than 1 or greater than 1 the disease free equilibrium point is stable or unstable respectively,so that the disease dies out or persists within the *** simulations were carried out using MATLAB to support our analytical *** simulations show that how double dose vaccination affect the dynamics of human population.

关键词： stochastic model Measles Basic reproduction number Stability analysis Sensitivity analysis Numerical simulation

Sequence-Oriented stochastic model of RO-TRNGs for Entropy Evaluation

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Chinese Journal of Electronics 2020年第2期29卷 371-377页

作者： ZHU Shaofeng XI Wei FAN Limin CHEN Hua CHEN Meihui FENG Dengguo Institute of Software Chinese Academy of Sciences State Key Laboratory of Cryptology University of Chinese Academy of Sciences Electric Power Research Institute China Southern Power Grid

Ring oscillator-based true random number generators(RO-TRNGs) are widely used to generate unpredictable random numbers for cryptographic *** is usually adopted to quantitatively measure the unpredictability of a TRNG. There have been several stochastic models such as the time-oriented and phaseoriented ones built to evaluate the entropy of ElementaryRO-TRNGs with single oscillator. However, these models are not suitable for the TRNGs composed of multiple oscillators(Multiple-RO-TRNGs), which can obtain more randomness and higher throughput. Considering this,we propose a sequence-oriented stochastic model for the entropy evaluation of RO-TRNGs, named the first-order stationary Markov source model. This model is extensible for the Multiple-RO-TRNGs. Based on that, we present a detailed method to determine the entropy of Multiple-ROTRNGs. Our proposed model is verified by ***, our method can also be a guide to design ROTRNGs with both high entropy and high throughput.

关键词： True random number generator(TRNG) Ring oscillator Entropy stochastic model Randomness

A New stochastic model for Classifying Flexible Measures in Data Envelopment Analysis

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Journal of the Operations Research Society of China 2021年第3期9卷 569-592页

作者： Mansour Sharifi Ghasem Tohidi Behrouz Daneshian Farzin Modarres Khiyabani Department of Mathematics Tabriz BranchIslamic Azad UniversityTabrizIran Department of Mathematics Central Tehran BranchIslamic Azad UniversityTehranIran

The way to deal with flexible data from their stochastic presence point of view as output or input in the evaluation of efficiency of the decision-making units(DMUs)motivates new perspectives in modeling and solving data envelopment analysis(DEA)in the presence of flexible *** the orientation of flexible data is not pre-determined,and because the number of DMUs is fixed and all the DMUs are independent,flexible data can be treated as random variable in terms of both input and output *** a result,the selection of flexible variable as input or output for n DMUs can be regarded as binary random *** the randomness of choosing flexible data as input or output,we deal with DEA models in the presence of flexible data whose input or output orientation determines a binomial distribution *** study provides a new insight to classify flexible variable and investigates the input or output status of a variable using a stochastic *** proposed model obviates the problems caused by the use of the large M number and using its different values in previous *** addition,it can obtain the most appropriate efficiency value for decision-making units by assigning the chance of choosing the orientation of flexible variable to the model *** proposed method is compared with other available methods by employing numerical and empirical examples.

关键词： Data envelopment analysis Flexible variables stochastic model Random variable Classifying

stochastic model for the Spread of the COVID-19 Virus

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Applied Mathematics 2021年第1期12卷 24-31页

作者： Majdi Elhiwi Probability and Statistics Laboratory UR/11/ES-76 Faculty of Sciences of Sfax Sfax Tunisia

The COVID-19 pandemic has become a great challenge to scientific, biological and medical research as well as to economic and social sciences. Hence, the objective of infectious disease modeling-based data analysis is to recover these dynamics of infectious disease spread and to estimate parameters that govern these dynamics. The random aspect of epidemics leads to the development of stochastic epidemiological models. We establish a stochastic combined model using numerical scheme Euler, Markov chain and Susceptible-Exposed-Infected-Recovery (SEIR) model. The combined SEIR model was used to predict how epidemics will develop and then to act accordingly. These COVID-19 data were analyzed from several countries such as Italy, Russia, USA and Iran.

关键词： stochastic model COVID-19 EULER Method SEIR model Markov Chain

stochastic model of a Cold-Stand by System with Waiting for Arrival &Treatment of Server

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American Journal of Operations Research 2016年第4期6卷 334-342页

作者： Rohtash K. Bhardwaj Ravinder Singh Department of Statistics Punjabi University Patiala India

The service facility or server is the key constituent to keep a system operational for desired period of time. As any eventuality with the system necessitates immediate presence of it (server) so the time point of arrival and treatment of server significantly affects the system performance. This paper works out the steady state behavior of a cold standby system equipped with two similar units and a server with elapsed arrival and treatment times following general probability distributions. It practices the theory of semi-Markov processes, regenerative point technique and Laplace transforms to derive the expressions for state transition probabilities, mean sojourn times, mean time to system failure, system availability, server busy period and expected frequencies of repairs and treatments. The profit function is also developed taking different costs and revenue in to account. For tracing wider applicability of the model for different reliability and cost-effective systems, a particular case study is also presented as an illustration.

关键词： stochastic model Cold-Standby System Server Failure Regenerative Point Arrival and Treatment Times

stochastic model of GPS/BD Combined Standard Single Point Positioning

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Stochastic Model of GPS/BD Combined Standard Single Point Po...

stochastic model of GPS Doppler:evaluation,modeling and performance

第三届中国卫星导航学术年会

作者： Wenkun Yu 1,Wujiao Dai 1,Xiaoli Ding 2,Wentao Yang 2,Xiao Gao 1 1 School of Geosciences and Info-physics Engineering,Central South University,Changsha,Hunan,China 2 Department of Land Surveying and Geo-Informatics,The Hong Kong Polytechnic University,Hung Hom,Kow Loon,Hong Kong

Reasonable determination of weights is the key factor in giving full play to advantages of GPS/BD combined ***,Helmert VCE （Variance Component Estimation） is employed aiming at adjusting the variance-ratio between the two heteroscedastic ***,the precise priori weight matrix can enhance the convergence of iteration methods based on posteriori information,reduce the iteration’s ***,system related errors,together with outliers,influence the estimation,leading to a distorted stochastic ***,in this paper,based on robust Helmert VCE and using integrated priori accuracy,taking various error sources into consideration,an initial weighing method for combined system is suggested.

关键词： GPS/BD robust Helmert stochastic model

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Stochastic model of GPS Doppler:evaluation,modeling and perf...

Applicability of Markov chain-based stochastic model for bubbling fluidized beds

第三届中国卫星导航学术年会

作者： Zebo Zhou 1 Yunzhong Shen 2 Bofeng Li 31 Inst.of Astronautics and Aeronautics,University of Electronic Science Technology of China,No.2006,Xiyuan Ave,West Hi-Tech.Zone,611731,Chengdu,P.R.China2 Dept.of Surveying and Geo-informatics Engineering,Tongji University,1239 Siping Rd,200092 Shanghai,P.R.China3 GNSS Research Centre,Department of Spatial Sciences,Curtin University of Technology,GPO Box U1987,Perth WA 6845,Australia

Doppler measurement is popularly applied to estimate the vehicle’s velocity in GPS navigation and its stochastic characteristics attach a great importance to the quality of velocity *** this contribution,firstly a single differenced （SD） Doppler observation is established with the known ***,the precision of un-differenced Doppler measurement is derived from SD observation *** on the model above,the stochastic characteristics of Doppler measurements are evaluated,including elevation-dependent standard deviation,cross correlation between-frequency as well as the time correlation of each *** real Doppler data collected on ultra-short baselines using six types of receivers for a few hours are carried out to evaluate and analyze the Doppler stochastic *** results show that the precision of Doppler measurement is obviously dependent on satellite elevation *** measurements between dual-frequency are evidently cross-correlated and time correlation is proven nonexistent for all GPS *** on these experiment results,an elevation angle dependent Doppler stochastic model is proposed and fitted with curve fitting tool of *** last,both static and kinematic tests are carried out to demonstrate the efficiency of our proposed stochastic *** results indicate that the proposed Doppler stochastic model significantly improves the velocity accuracy and indirectly contributes to GPS positioning solutions.

关键词： GPS Doppler stochastic model cross correlation time correlation elevation angle model

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Journal of Southeast University(English Edition) 2015年第2期31卷 249-253页

作者：庄亚明陈晓平刘道银东南大学能源热转换及其过程测控教育部重点实验室南京210096

A Markov chain-based stochastic model （MCM） is developed to simulate the movement of particles in a 2D bubbling fluidized bed （BFB）. The state spaces are determined by the discretized physical cells of the bed, and the transition probability matrix is directly calculated by the results of a discrete element method （DEM） simulation. The Markov property of the BFB is discussed by the comparison results calculated from both static and dynamic transition probability matrices. The static matrix is calculated based on the Markov chain while the dynamic matrix is calculated based on the memory property of the particle movement. Results show that the difference in the trends of particle movement between the static and dynamic matrix calculation is very small. Besides, the particle mixing curves of the MCM and DEM have the same trend and similar numerical values, and the details show the time averaged characteristic of the MCM and also expose its shortcoming in describing the instantaneous particle dynamics in the BFB.

关键词： stochastic model Markov chain discrete elementmethod (DEM) bubbling fluidized bed (BFB)