Ljubomir Miladinovic

Method of evaluating the impact of ERP implementation critical success factors – a case study in oil and gas industries

The so far implemented enterprise resource planning (ERP) systems have in many cases failed to meet the requirements regarding the business process control, decrease of business costs and increase of company profit margin. Therefore, there is a real need for an evaluation of the influence of ERP on the companys performance indicators. Proposed in this article is an advanced model for the evaluation of the success of ERP implementation on organisational and operational performance indicators in oil–gas companies. The recommended method establishes a correlation between a process-based method, a scorecard model and ERP critical success factors. The method was verified and tested on two case studies in oil–gas companies using the following procedure: the model was developed, tested and implemented in a pilot gas–oil company, while the results were implemented and verified in another gas–oil company.

The Eclipses Abacus, the mechanical predictor of the solar and lunar eclipses

This paper exposes and explains the synthesis of a mechanism, the Eclipses Abacus, by which the date of solar and lunar eclipses can be predicted and determined sufficiently accurately. Moreover, a three-dimensional (3D) model of this mechanical device is created by using Solid Works application and the simulation of its operation is accomplished by which the accuracy of its predictions can be demonstrated and inspected. This work is significant mainly for education in the field of 3D modeling, mechanism synthesis, and simulation. Moreover, the Eclipses Abacus is interesting for teaching courses in astronomy since it can demonstrate solar and lunar eclipses simply and clearly.