# Evaluating the Effectiveness of COVID-19 Bluetooth-Based Smartphone Contact Tracing Applications
## 2 Related Works  
Surveillance and control of emerging infectious diseases are essential for public health. The utilization of new technologies, such as Internet-based monitoring, remote sensing, infectious disease modeling, mobile phones and telecommunication, can predict, prevent and control these infectious diseases [18]. It is a new approach to deal with epidemics, usually named digital epidemiology [4]. Particularly, mobile devices can help with the detection of infectious contacts, as detailed in this paper. Mobile crowdsensing (MCS) can be used to address COVID-19 [19]. The combination of mobile crowdsensing (MCS) with opportunistic networking (OppNet) allows mobile users to share sensed data easily and conveniently without the use of fixed infrastructure [20]. The combination of these two technologies is referred to as opportunistic mobile crowdsensing (OMC). Particularly, OMC is inexpensive, since there is no need for network deployment, offering also good spatiotemporal coverage. Opportunistic mobile crowdsensing can use two sensing approaches: (i) mobile sensing, based on obtaining data from the mobile's hardware sensors, such as accelerometers, gyroscopes, GPS, network connectivity, camera, microphone, etc. ; and (ii) social sensing, which leverages user-contributed data from social networks, considering participants as social sensors. Nevertheless, this social sensing might serve as a complementary source to physical mobile sensing [21]. A way to detect and trace contacts is by using wireless sensor network technologies, such as ZigBee or Bluetooth. [PERSON] et al. [22] performed one of the first experiments using MOTES. They obtained high-resolution data of interpersonal contacts during a typical day at high school, allowing the reconstruction of the social network that was relevant from an infectious disease transmission perspective. The paper includes an extension of the basic SIR epidemic model which includes the exposed individuals with the aim of evaluating the disease spread and the impact of vaccination measures. In recent years there has been a growing concern in evaluating the effectiveness of contact tracing in epidemics. Contact tracing can be a useful tool, where the latent next-generation cases are the primary focus. It has been proven to be a very successful strategy when the quantity of infectious cases is low, or at the early stages of an outbreak, or particularly when the disease may be asymptomatic (but still contagious) [3]. Other papers estimate the factors that makes an infection controllable [23; 24]. For example, in [23], the authors showed that the success of control measures such as isolation and quarantine is determined by the proportion of transmission occurring prior to the onset of overt clinical symptoms (or via asymptomatic infection) as measured by the reproductive number R0. [PERSON] et al. [24] concluded that the variability in time to detection is favorable for effective tracing and that tracing effectiveness need not be sensitive to the duration of the latent period and tracing delays. The two main approaches for modeling contact tracing are the following [25]: population-based modeling and agent-based modeling. The former is a top-down approach representing disease dynamics on a system level which is typically used to analyze research questions from a macroscopic perspective; the latter is a bottom-up approach dealing with each person as an agent with their own movements and infection states and is usually used to evaluate heterogeneous and adaptive behaviors. In general, agent-based modeling is more realistic, although it can be computationally demanding. Some works [26; 27] have introduced detailed stochastic models which are simplified to a deterministic model to get the most significant dynamics of the epidemics. Most of the epidemic models (population-based modeling) are based on the basic SIR (susceptible infected recovered) model, considering also quarantine and isolation measures. That is the basic model used in this paper.