This paper presents the stochastic approach to congestion that is unknown to some users or designers of telecommunication networks. Its purpose is to help designers predict network behavior, characterize load, determine number and size of components, these elements are important for those who want to optimize the network in terms of its architecture, so as to meet the required quality of service standards by taking the most economical route possible. This approach will be based on the modelizations of the arrival and the waiting calls on the network following some hypotheses. A key element of call reception to consider is the base transmission station (BTS) in the GSM network or the NODE B in the 3G to 4G + networks.
A mathematical modeling of Hepatitis C Virus (HCV) dynamics has been presented in this paper. The proposed model, which involves four coupled ordinary differential equations, describes the interaction of target cells (hepatocytes), infected cells, infectious virions and non-infectious virions. The model takes into consideration the addition of ribavirin to interferon therapy and explains the dynamics regarding biphasic and triphasic decline of viral load in the model. A critical drug efficiency parameter has been defined and it is shown that for efficiencies above this critical value, HCV is eradicated whereas for efficiencies lower this critical value, a new steady state for infectious virions is reached, which is lower than the previous steady state.