## 2 Related Research
### Quality Requirements in Smart Cities  
A smart city is a concept that integrates information and communication technology in every element in an urban area to improve the efficiency and quality of life. Interactions between citizens, third parties, and city departments are getting more and more complex with the deployment of digital and online applications in various types of systems in a smart city environment [1]. Mobile devices, such smart phones, smart vehicles, and wearable devices, are equipped with features, applications, and various types of sensors that allow for data collection and data-sharing capabilities. These devices interact, communicate, and exchange messages in a smart city environment via social networking, crowdsourcing, and crowdsensing [25].  
Fulfilling non-functional or quality requirements, such as privacy and confidentiality, during the execution of smart city applications is still an open issue [26]. The needs to overcome the challenges have been discussed in the literature. The existing proposed solutions for agent quality requirements, such as trust and privacy, of smart city applications are presented in Table 2. [PERSON] et al. [27] proposed a framework that provides features for the privacy-protected and trusted service provisioning in smart cities. An encryption scheme was proposed by [PERSON] et al. [28] to provide confidentiality for wearable devices that perform data collection in a smart city environment. The design and development of anonymous and accountable access control was presented by [PERSON] et al. [29] to be deployed in a machine to machine enabled (M2M-enabled) IoT. It is an example of privacy-by-design where privacy-aware access control is implemented. A privacy-preserving architecture called Authorized Analytics performs differential privacy techniques to be implemented in a mobile IoT. [PERSON] et al. [30] proposed Secure Mobile Agent Protocol (SMAP), which provides confidentiality and integrity for a mobile agent to protect vehicular communication systems in smart cities from security attacks. A privacy-preserving rating data publishing model was introduced by [PERSON] et al. [31] to ensure privacy in recommender systems in smart cities. A trust strategy called data trustworthiness enhanced crowdsourcing strategy (DTCS) proposed a method for trust relationship establishment to enhance data trustworthiness in a mobile crowdsourcing system in smart cities [8].  
The proposed solutions to establish trust, privacy, confidentiality, and integrity have been presented in the listed literature. Solutions including framework, encryption, design, architecture, protocol, model, and strategy elements have been proposed. However, despite implementing the above approaches, the dynamic agent profile status, social activities, and shared contents that keep  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**No.**} & \multirow{2}{*}{**Proposed Solutions**} & \multicolumn{4}{c}{**Quality Properties**} \\ \cline{3-6}  & & **Trust** & **Privacy** & **Confidentiality** & **Integrity** \\ \hline
1 & Security and privacy framework [27] & ✓ & ✓ & - & - \\
2 & Anonymous and Accountable Access & & & ✓ & - & - \\  & Control Design [29] & - & ✓ & ✓ & - \\
3 & Authorized Analytics Architecture [32] & - & ✓ & ✓ & - \\
4 & Secure Mobile Agent Protocol (SMAP) [30] & - & - & ✓ & ✓ \\
5 & Ciphertext-Policy Attribute-based Encryption & - & - & ✓ & - \\  & (CP-ABE) [28] & - & - & ✓ & - \\
6 & Privacy-preserving collaborative filtering model [31] & - & ✓ & - & - \\
7 & Data trustworthiness enhanced crowdsourcing & & ✓ & - & - \\  & strategy (DTCS) [8] & & ✓ & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 2: The mapping of the proposed solutions for smart city quality requirements with the focused quality properties.  
changing during run-time may still cause unintended violations of quality properties. Thus, a gap was identified and a solution was proposed to detect agent quality properties violations during run-time.