## 5 Testing and Evaluation  
### Evaluation of the IoT Architectures  
In this section, we discuss the evaluation of the proposed IoT architectures in different conditions. In addition, multiuser therapy wearable architecture is evaluated in terms of latency concerning the number of users, the distance between users, and speed of the vehicle in which the user is travelling (when the user is using the HOD during travel). This project was approved by the Amrita Ethics Committee for Engineering Research Projects (AECERP) on 31 October 2019 with project identification code AU/AM/HUT/2019-03. As a device that is using cloud for data storage and control (IoT framework-based control), latency, data loss, and type of network are the three important parameters considered in this evaluation. All these tests are performed by the four volunteers (healthy subjects, male, age between 18-22). In addition to the network, all the results are also influenced by the hardware that we used for IoT. We used the same hardware for the entire evaluation as discussed in the section System Architecture for Hand Therapy. The time required and data loss are measured for the following actions:T1--Data reception through cloud by therapist  
T2--HOD control by therapist  
T3--HOD control by patient  
T31--HOD control by patient using voice  
T32--HOD control by patient using touch  
T4--Data reception through cloud by patient (mobile application)  
The four IoT architectures are represented in the table as:  
A1--Therapist therapy wearable architecture  
A2--Dual therapy wearable architecture  
A3--User therapy wearable architecture  
A4--Multiuser therapy wearable architecture (two users in two different rooms)  
In Table 1, the latency for different operations in the proposed IoT architectures are compared. We know that the latency is higher in 3G than 4G in all the cloud-based operations in these architectures. The touch control works better than voice control in terms of latency. In voice control, the conversion time and misinterpretations cause some delay in the control. User therapy wearable architecture has a minimum latency of 1.65 s and 1.38 s to send data to the patient's mobile app through cloud. The multiuser therapy wearable architecture has high latency to receive the data through cloud. For patients to receive data, it took 2.76 s using 3G and 2.21 s using 4G. Similarly, for the therapist to receive the data from the cloud, it took 2.71 s using 3G and 2.27 using 4G. The data loss in the four proposed IoT architectures in various sampling rates are given in Tables 2-5. The data loss maximum was 1050 samples/s and the minimum was 750 samples/s. The data loss was higher when we were using the 3G network than when we were using the 4G network. In terms of data loss, multiuser therapy wearable architecture gives a similar performance compared with the other three architectures, if two users are considered and were in two different rooms in a house. Compared with other architectures, latency in the multiuser therapy architecture depends on a lot of factors. From Tables 6-8, we checked this variation with respect to the number of users, distance between the users, and the speed of the vehicle in which the user was traveling. From Table 6, we found that the number of users (in a house) was not dependent on the latency. The latency we got was less when four users were using the device compared with when it was three. From Table 7, we observed that the latency was proportional to the distance between the users but was not very significant. A few millisecond delay was observed when the distance was increased by 50 m. The latency increased with respect to the speed of the vehicle (as shown in Table 8) in which the user was travelling in both 3G and 4G. A ten-kilometer variation in speed caused a delay of 0.4 s to receive the data from clouds.