# A Systematic Mapping of Quality Models for AI Systems, Software and Components
## 2 Background of the Study
### Software Component Quality Models  
Firstly, there will be some definitions of software components from the literature. A software component quality model aims to evaluate the quality of the component level [35]. According to [PERSON] et al. [36], a software component is a unit of composition with contractually specified interfaces and explicit context dependencies only. Despite the definition, software component quality models should be tailored to use only the characteristics that apply to components [36]. Therefore, the quality of software components is measured via interfaces due to the unavailability of information on the component to the third parties [37]. This kind of measurement will increase the understandability of component reusability. Moreover, external metrics are based on whatsoever information is available regarding the components such as interface and component documentation [38]. This section will discuss several existing studies of software component quality models, such as [39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54]. [PERSON] and [PERSON] [39] identified commercial off-the-shelf (COTS) component quality characteristics based on ISO 9126, namely, functionality, reliability, usability, efficiency, maintainability, and portability. [PERSON] and [PERSON] [40] proposed a quality model specifically for COTS component evaluation and selection. The quality models contain the following quality characteristics: functionality, reliability, usability, efficiency, maintainability, and manageability. [PERSON] et al. [41] carried out a study of the software component quality model (SCQM), which aims to evaluate the quality of software components. The SCQM contains eight main quality characteristics, which are functionality, reliability, usability, efficiency, maintainability, portability, reusability, and traceability, and each of these have sub-characteristics. In [42], the authors proposed a component quality model for COTS components based on ISO 9126. COTS are commercially available software components. The authors identified quality characteristics, sub-characteristics, and measures for COTS. The study presented nine quality characteristics, which are maintainability, testability, functionality, efficiency, reliability, usability, security, portability, and reusability. [PERSON] et al. [43] proposed a set of quality characteristics and sub-characteristics for reusability of software components. The study identified three main quality characteristics, which are understandability, adaptability, and portability. Understandability has two sub-characteristics, documentation level and observability. Adaptability has one sub-characteristic, customizability. Portability also has one sub-characteristic, external dependency. To evaluate the proposed software components, a survey was conducted at Universiti Malaysia Terengganu (UMT). The respondents included 18 software component experts, 8 officers for application development, and 10 computer science lecturers. In [44], the authors investigated the quality characteristics of software component selection based on ISO 2010:2011. The study contains five quality characteristics: effectiveness, efficiency, satisfaction, safety, and usability. [PERSON] and [PERSON] [45] proposed a software component quality model specifically for the design level. The authors found eleven quality characteristics, which are compositionality, reusability, coupling, configurability, encapsulation, complexity, usability, slim, testability, cohesion, and interface documentation. [PERSON] and [PERSON] [46] presented a set of quality characteristics and sub-characteristics for software components based on the ISO 9126 standard. The study contains six main quality characteristics, namely, functionality, reliability, usability, efficiency, maintainability, and portability. [PERSON] et al. [47] designed a software component quality model based on ISO 9126.