Search

Detonation control simulation is an important issue in the field of ammunition performance analysis. Extensive research has been carried out at home and abroad, this paper presents a theory and method of detonation control, including detonation control theory and method, initiation point calculation method, guidance error calculation, fuze trigger calculation, coordinate transformation of fuze trigger point start point, recursive calculation of fuze start delay and so on. The accurate starting of fuze and the simulation of ammunition detonation control are realized, combined with practical application, good results have been achieved.

In this paper, we present an SEIIaHR epidemic model to study the influence of recessive infection and isolation in the spread of COVID-19. We first prove that the infection-free equilibrium is globally asymptotically stable with condition R01. By using the COVID-19 data in India, we then give numerical simulations to illustrate our results and carry out some sensitivity analysis. We know that asymptomatic infections will affect the spread of the disease when the quarantine rate is within the range of [0.3519, 0.5411]. Furthermore, isolating people with symptoms is important to control and eliminate the disease.

Collaborative filtering (CF) is widely applied in recommender systems. This study aims to incorporate product relationships into traditional CF based recommendation algorithms to address data sparsity and cold start problems. We propose a novel matrix factorization model, where each user has a category-specific user latent factor vector to more accurately describe the user latent factors. In the meanwhile, the explicit product relationships have been leveraged as the regular term to constrain the learning of product latent feature vector. Lastly, the empirical results demonstrate the superiority of our model against other counterparts on recommendation accuracy. Besides, our model has a good theoretical and practical significance.

In this paper, a delayed SIR model with exponential demographic structure and the saturated incidence rate is formulated. The stability of the equilibria is analyzed with delay: the endemic equilibrium is locally stable without delay; and the endemic equilibrium is stable if the delay is under some condition. Moreover the dynamical behaviors from stability to instability will change with an appropriate critical value. At last, some numerical simulations of the model are given to illustrate the main theoretical results.