Data harmonization in IoT-based distributed healthcare system: A review

The proliferation of Internet of Things (IoT) aided healthcare systems in distributed environment are considered for providing global access and references for personal and distributed electronic health services, whose popularity has come to fore. A distributed healthcare system based on the Internet of Things (IoT) connects different medical resources through the use of distributed databases and distributed DBMSs. This enables the provision of intelligent, reliable, and effective healthcare services to patients with chronic illnesses and the elderly. Such systems are called IoT-based distributed healthcare systems (IoT-DHS). The massive amount of heterogeneous data generated becomes cumbersome in processing and analyzing due to variations in data formats. Also, such systems are gradually moving from traditional ETL technique to real-time processing. Hence there is need for efficient handling of such heterogeneous data in real time IoT-DHS. This can be solved by technique called data harmonization (DH) which unifies the representation of such heterogeneous data from IoT-DHS before using IoT-DHS data for further analysis to take decisions. The main emphasis of this paper is to survey state-of-the-art works in Data Harmonization used for IoT-DHSs and a taxonomy is derived based on these systems considering various aspects such as location of processing, data storage management, and input/output data formats. This paper helps technical people who are specifically working with heterogeneous data of medical professionals, investigators and scientists interested in IoT technologies for medical domain.