# Empowering Clinical Engineering and Evidence-Based Maintenance with IoT and Indoor Navigation +
## 3 Materials and Methods
### Deployment  
The OHIO framework utilizes a REST architecture to enhance data exchange and facilitate seamless integration with third-party applications. It relies on two primary front-end applications: a web application and an upgraded and redesigned version of the HiWay mobile application. Both applications are deployed within a complete IoT framework specifically designed to optimize the maintenance process of medical equipment for clinical engineering services. The whole framework has been specifically developed to overcome the identified unmet needs (Section 1.1). In particular, the upgraded version of HiWay is now able to perform more complex and advanced features (see Section 4.2) than the previous release, which was developed only for patient and visitor navigation. The management web application and HiWay interact with a set of APIs to share data with the underlying back-end technologies and infrastructures. Specifically, the dedicated management module interacts with the hospital's CMMS to retrieve work orders (WOs) associated with the selected medical equipment, streamlining maintenance activities. This module cross-checks data about the medical equipment and its maintenance schedule with precise device location information provided by SPOT. Communication with SPOT allows the APIs to dynamically retrieve up-to-date destination location information, ensuring instant reflection of any structural or organizational changes in HiWay. Apache Cordova is used as the mobile development framework for HiWay, chosen for its continuity with the previous version [24]. The Health Technology Manager identified specific Electro-medical Equipment Hubs (EEHs) as collection and maintenance areas for each ward of the building in the pilot hospital used for initial testing. This strategy restricted the deployment area and facilitated quicker data collection. The positions of mapped medical devices are retrieved using BLE tags attached to them. Bluetooth antennas were strategically installed in the identified collection areas to capture the available BLE signals (Figure 3). BLE antennas and tags were provided by the external technology vendor BlueUp [32]. Only movable equipment was tagged (fixed installation devices, such as computed tomography (CT) and magnetic  
Figure 2: HiWay in off-site mode (**left**) allows saving custom routes for planning scopes, before reaching the premises. Routes can then be loaded once they arrive on-site and be used to obtain directions in real time (**middle** and **right**). resonance imaging (MRI) scans, were excluded because they do not need to be moved to the EEH for maintenance as their positions are time-invariant and known by technicians). The initial tests in the pilot hospital focused solely on ultrasound (US) machines, totaling 14 devices. US scans were chosen because the Health Technology Manager believed they would benefit most from the proposed framework, given the number of losses in previous years. The identified hubs were marked in SPOT and associated with the related medical equipment to facilitate BMETs in locating and maintaining equipment without the need for rescheduling due to missing intervention. When a recognized tag enters or exits the reach of an antenna, both its MAC (Media Access Control) address and the antenna's address are transmitted to the main OHIO server within the hospital's network. The new features of HiWay, together with the functionalities provided by the management application, ensure that the status of the equipment that must undergo maintenance (collected in the EEH or not) is known in real time. This allows for better scheduling of the maintenance operations, preventing the identified unmet need from occurring (Section 1.1). A detailed description of both the management web application and the new version of HiWay is provided in Section 4. Figure 4 shows the fingerprinting quality related to WiFi, magnetic, and BLE mapping for a given story of the hospital.