Mobile Sensing, Simulation and Machine-learning Techniques: Improving Observations in Public Health

Entering an era where mobile phones equipped with numerous sensors have become an integral part of our lives and wearable devices such as activity trackers are very popular, studying and analyzing the data collected by these devices can give insights to the researchers and policy makers about the ongoing illnesses, outbreaks and public health in general. In this regard, new machine learning techniques can be utilized for population screening, informing centers of disease control and prevention of potential threats and outbreaks. Big data streams if not present, will limit investigating the feasibility of such new techniques in this domain. To overcome this shortcoming, simulation models even if grounded by small-size data can represent a simple platform of the more complicated systems and then be utilized as safe and still precise environments for generating synthetic ground truth big data. The objective of this thesis is to use an agent-based model (ABM) which depicts a city consisting of restaurants, consumers, and an inspector, to investigate the practicability of using smartphones data in the machine-learning component of Hidden Markov Model trained by synthetic ground-truth data generated by the ABM model to detect food-borne related outbreaks and inform the inspector about them. To this end, we also compared the results of such arrangement with traditional outbreak detection methods. We examine this method in different formations and scenarios. As another contribution, we analyzed smart phone data collected through a real world experiment where the participants were using an application Ethica Data on their phones named. This application as the first platform turning smartphones into micro research labs allows passive sensor monitoring and sending over context-dependent surveys. The collected data was later analyzed to get insights into the participants' food consumption patterns. Our results indicate that Hidden Markov Models supplied with smart phone data provide accurate systems for foodborne outbreak detection. The results also support the applicability of smart phone data to obtain information about foodborne diseases. The results also suggest that there are some limitations in using Hidden Markov Models to detect the exact source of outbreaks