# CoKnowEMe: An Edge Evaluation Scheme for QoS of IoMT Microservices in 6G Scenario
## 2 Materials and Methods
### Acceptability  
The concept of acceptability has a complex nature as it depends on various factors belonging to different fields such as human sciences, engineering and psychology. Acceptability can be considered as the precursor to the use of a service and it can be considered as the composition of practical and social factors. The most used model to understand technological acceptance processes is the Technological Acceptance Model (TAM), which states that the intention to adopt a technology is already a good predictor for its use [28]. The TAM is based on the following fundamental constructs, Perceived Utility (PU), Perceived Ease of Use (PEOU), User Attitude (A) and Behavioural Intentions (BI), to explain the technological acceptance; however, as argued in several studies [29; 44; 45], the TAM does not take into account social influence in studying the adoption and use of technology. For this reason in [46] the model is extended, including social influence and psychological attachment. Social influence affects the behaviour of the individual on several levels classified as internalization, identification and conformity. Internalization is the highest level when an individual accepts influence as it fully corresponds to his own value system; identification represents the intermediate level when an individual accepts influence because he intends to establish or maintain a satisfactory relationship with another person or group; compliance is the lowest level--in this case an individual adopts a certain behaviour not because he believes in its content but because he expects to obtain rewards or avoid a punishment. The TAM has been widely used as a basis for the design of other models such as the Unified Theory of Acceptance and Use of Technology (UTAUT). Reference [29] extends the TAM to include determining factors (such as performance expectancy, effort expectancy, social influence, facilitation) and mediation factors (such as sex, age, experience, voluntariness). The advantage of these models is that they are applicable to several technologies. Other models have been proposed for specific use, such as the Mobile Technology Acceptance Model (MOPTAM) [29], which focuses on the acceptance of mobile phones, the Senior Technology Acceptance and Adoption Model (STAM), also designed on the basis of the TAM narrows the field to the elderly, and the Rural Technology Acceptance Model (RUTAM), according to which in rural areas social influence has a more important role than technology itself in determining acceptance [29; 45]. The Expectation Confirmation Model (ECM-IT) [28] in the context of IT investigates the continued (or post-adoption) use of IT by exploiting three antecedent constructs, which are: User satisfaction with IT, extent of user confirmation and post-adoption expectations, the latter represented by perceived utility. This model considers satisfaction as the main influence on the user's intention to continue using the technology. The extension of the previous models is the EECM-IT--Extended ECM-IT [28]--born from the merger of the TAM and ECM-IT, which considers, in addition to the perceived utility, also the perceived ease of use.