# Systems Integration and Cost Modelling

## Project Summary

The process of combining a component’s subsystems together into one system and ensuring that they function together is known as S**ystems Integration**. A system is made up of subsystems all working together in order to achieve the required function. There are three main methods of integration. Vertical integration involves integrating the subsystems according to their function, enabling a time and cost effective integration. Star integration or spaghetti integration involves integration systems where each system is interconnected to each of the remaining subsystems. This is a flexible method but the time and costs required increase exponentially when adding additional subsystems. The third method is horizontal integration or enterprise service bus (ESB). This method is dedicates a specialised subsystem to communication between other subsystems. This reduces the number of connection (interfaces) required.

**Cost modelling** is the process of using mathematical algorithms or parametric equations in order to estimate the costs of a product or project. The results of the models are used to determine whether the project should proceed and are also factored into the business plans and budgets. The algorithms are normally computerised and can be standardised if required. A simple model may use standard spreadsheet products. The input of parameters that describe the attributes of the project or product and any physical resource requirements are used within the model. The model will then determine various output resources requirements in time and cost.