MODELLING OF ENUGU STATE MONTHLY RAINFALL USING BOX AND JENKINS METHODDOLOGY

The paper examined the rainfall distribution of Enugu state in Nigeria. Box-Jenkins methodology was used to build ARIMA model to analyze data and forecast for the period of 15 years, from January, 2002 to December, 2016 and to predict for the future. We observed that the average annual rainfall of Enugu state ranges from 124mm to 179mm. The irregularity in annual rainfall of Enugu State one and half decades ago is a bit large, indicating that climate stability is high in the state. Different time series models were diagnostically checked, and tested for Enugu state and at last an SARIMA (0, 0, 0) (1, 0, 1)12 model is chosen as the proposed best model. The proposed model was used to forecast two years’ monthly rainfall value for the state. The results indicated that relatively there is a tendency of increasing in trend of future rainfall values in the state

Modelling language extinction using Susceptible-Infectious-Removed (SIR) model

The study presents a stochastic epidemic model applied to the model of indigenous language extinction. The Susceptible-Infectious-Removed (SIR) categorization of an endemic disease has been reformulated to capture the dynamics of indigenous language decline, based on the assumption of non-homogeneous mixing. The time in which an indigenous language is expected to be extinct was derived using a modified SIR model with the population segmented into several sub-communities of small sizes representing family units. The data obtained from the 2016 indigenous language survey conducted in several parts of Nigeria and from the 2013 Nigeria Demographic Health Survey (NDHS) were used to estimate the key parameters of the model for Nigeria’s several indigenous languages. The parameters of interest included the basic reproduction number, the threshold of endemicity, and the time in which a language is expected to be extinct, starting from the endemic level. On the basis of the time in which a language is expected to be extinct, several of the surveyed languages appeared to be in a precarious condition, while others seemed virile, thanks to a high language transfer quotient within families