We used the monthly share prices of all Nigeria Share Price index from April, 2000 to January, 2014 to identify and model the volatility of asset return in the Nigerian Stock Exchange. We compared several ARMA-GARCH models that best fits the series. The result of our study shows that the ARMA(1,1)-GARCH (1,1) model best describes the volatility of the return. The volatility of the returns was found to be quite persistent, i.e. current volatility can be explained by past volatility that tends to persist over time.

Virtual Reality (VR) has been identified as one of the constructive medium to support the teaching-learning process. It is persistently explored by researchers in order to reap the most benefits from the technology in education. Among reasons for the usage of VR application in learning environment are due to its provision of interactivity among realistic complex structure of three-dimensional (3D) environment while giving the feel of being there to users. However, a broad framework and model to construct the theory and connection in this domain, particularly virtual reality for desktop or DesktopVR, has hardly been developed and evaluated. Therefore, the objective of this paper is to determine the features and relevant factors which may contribute to learning environment. This paper offers a theoretical model in designing DesktopVR for learning environment.

This paper contributes a scheme for solving linear optimal control problem in systems run by Volterra integral equations. At first, the original optimal control problem of Volterra integral equations is transformed into an integral problem via the Pontryagins maximum principle, and then, we applied homotopy analysis method (HAM) to solve the integral problem. The proposed method is compared with other methods. Numerical results show that the HAM method is more powerful and faster.