You are a data scientist working for a leading technology company. Your company has recently developed a mobile application that collects and analyses large amounts of data from users. The app has gained significant popularity, and as a result, the amount of data being processed has increased exponentially. This has brought forth a number of challenges related to Big Data and efficient data synchronization on mobile devices. Your task is to analyse these challenges and propose solutions to overcome them.

$3\mathrm{.}1$ Evaluate machine learning techniques for Big Data processing in mobile apps and discuss them.