  We describe the architecture of Sammen Om Demens (SOD), an application for
portable devices aiming at helping persons with dementia when wandering and
getting lost through the involvement of caregivers, family members, and
ordinary citizens who volunteer.
  To enable the real-time detection of a person with dementia that has lost
orientation, we transfer location data at high frequency from a frontend on the
smartphone of a person with dementia to a backend system. The backend system
must be able to cope with the high throughput data and carry out possibly heavy
computations for the detection of anomalous behavior via artificial
intelligence techniques. This sets certain performance and architectural
requirements on the design of the backend.
  In the paper, we discuss our design and implementation choices for the
backend of SOD that involve microservices and serverless services to achieve
efficiency and scalability. We give evidence of the achieved goals by deploying
the SOD backend on a public cloud and measuring the performance on simulated
load tests.
