# Measuring Quality of Service in a Robotized Comprehensive Geriatric Assessment Scenario
## 6 Related Work  
Assessing non-functional properties is gaining attention as systems become more complex and need to fulfill qualities of service at run-time. In robotics, QoS metrics have been applied to different domains, such as Human-Robot Interaction (HRI) [22; 23] or human-machine teams [24], focusing on different non-functional properties, such as performance [25] or safety [26]. In general, QoS metrics are based on the observation of low-level contextual data to elaborate a more abstract perception of how the system works in terms of certain non-functional properties. For example, the metrics presented in [23] focus on productivity, efficiency, reliability, safety, and co-activity; [PERSON] et al. [25] and [PERSON] et al. [27] on performance; and [PERSON] et al. [26] on safety. Moreover, QoS metrics can be useful for system evaluation and benchmarking [24; 28], requirements checking [26; 27], and run-time adaptation [29]. Despite all the attention, there seems to be a lack of tools to support the specification of non-functional properties and the generation of the robot run-time artefacts to estimate QoS. In the following we describe approaches dealing with non-functional properties. The UML MARTE [30] profile provides a common way to model hardware and software aspects of real-time embedded systems. It allows users to annotate models with information relevant for performing quantitative predictions and performance analysis. The usual workflow is to: (1) annotate information about non-functional properties directly in the software models; (2) use a model transformation for generating analysis-domain models; and (3) perform formal analysis using specialized tools. This process provides engineers with the means to evaluate the system designs and to take informed action if necessary. In the same line, [PERSON] et al. [31] propose a modeling language to support the development of the robot control system based on SysML [32]. As MARTE, SysML is a UML profile that enables the specification of traceable requirements and analytical models. Other works propose modeling languages for specific non-functional concerns, for example, [PERSON] et al. [33] extend a model-driven software development process to include performance specifications associated with the robot components, which enables system-level timing analysis. [PERSON] et al. [34] present a model-based tool for safety assessment in robotic systems by using fault injection simulations. It is built on Papyrus4 Robotics [35] (a UML profile) and allows expressing context situations that can cause hazardous effects. Unfortunately, all these approaches do not seem to provide much benefit when it comes to non-standardized application-dependent properties, such as the \"voice interaction quality\" considered \begin{table}
\begin{tabular}{c c c} \hline \hline
**Time (s)** & **Observations** & **Contexts** \\ \hline
10 & O2:C8 & PersonDetected \\ \hline
145 & O1:O7 & PersonIsNextToChair \\ \hline
195 & O1:O7 & PersonIsSeated \\ \hline
205 & O1:C8 & PersonGetsUp \\ \hline
215 & O1:O7 & PersonIsSeated \\ \hline
235 & O1:O2 & Scored,FINISHED \\ \hline \hline \end{tabular}
\end{table} 
Table 13: Get Up & Go #1: (Left) Contexts and observations generated by the system. (Right) Graphical evolution of the properties values during the test. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Patient \#** & \multicolumn{3}{c}{**Performance**} & \multicolumn{3}{c}{**Interaction**} \\ \hline  & **max** & **min** & **last** & **max** & **min** & **last** \\ \hline
1,2,3,5,6,7,8,9,10,11,12,13 & 0.9987 & 0.5000 & 0.9987 & 0.9862 & 0.5000 & 0.9858 \\ \hline
4 & 0.9387 & 0.5000 & 0.8310 & 0.9387 & 0.5000 & 0.7067 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Get Up & Go real test results associated to the tests in Table 11 (see text for details). in our work. In many cases, developers end up opting for custom solutions, with the consequent increase in time, cost and complexity.