## 3 The Conceptual Framework Proposed
### Analyzing the Real-Use Environments and Implementing Living Labs
#### Prioritization  
Once the living lab components are identified, the next step is to prioritize them in the order that must be reflected in the living labs. As explained earlier, realism is one of the most important principles in using living labs. However, in some cases, it may not be easy to implement living labs perfectly, to be the same as reality, due to time and cost constraints. Moreover, not all products may have the three real-use environments with equal importance, depending on their characteristics.  
For example, an automatic airbag for hip joint protection is a recent product for the elderly [40]. It is worn like a belt at the waist, and then when a user suddenly falls down, the airbag bursts out of the product to protect the hip joint area. According to the frameworks in Figures 1-3, it is a product that people use directly by wearing both indoors and outdoors, and that does not work with other products or systems. Hence, the user context (e.g., age, gender, body size and type) and the physical context (e.g., terrain such as slope, indoor structure such as stairs, outside weather such as snow and rain) will have a higher priority than the technological context.  
Then, the priority can be further refined according to the test method that needs verification. For example, if the verification concerns how to measure the airbag deployment time and the appropriate threshold criteria, it would be more important to implement the product's physical use environment most closely to the reality in living labs. This is because in terms of the performance and user safety, the product should be able to guarantee that the air bag is always fired within a predetermined time in any conditions of the physical environment, including ordinary roads, slippery roads, slopes, and stairs.  
As this example case suggests, prioritizing the living lab components is another pivotal process when using living labs for verification purposes. So, a more structured method for the prioritization is presented in this study. As shown in Figure 5, the relative importance of the three real-use contexts can be compared in terms of four dimensions: function, performance, optimization, and relevance.  
The function perspective pertains to whether the major features of a product should be designed considering the characteristics of users, the compatibility or connectivity to other devices, or the natural and artificial environment. Next, the performance perspective is useful to compare whether the performance evaluation of the product necessitates the consideration of user characteristics,  
Figure 4: The Real-Use Environment of a Floor Noise Level Meter.  
compatibility or connectivity, or the physical use environments. The third perspective for prioritization (i.e., optimization) puts a focus on which of the three real-use environments should be considered more in order to optimize the product. Finally, the relevance perspective allows you to check whether the test methods and criteria that require verification are closely related to the user characteristics, the connectivity to other devices, or the natural and artificial environment.  
In sum, the four perspectives help prioritize the living lab components in a systematic manner. Using the questions corresponding to the four dimensions, the relative importance of the three actual use environments can be calculated. Then, the priority is determined in order of high score.