# An Activity Theory-Based Approach for Context Analysis, Design and Evolution
## 3 Putting Everything into Practice
### Building the NoA  
The building of an NoA following the postulates of activity theory involves finding the elements that structure the activity system for each of the subjects involved. For example, let us consider the shopper as an initial subject. As described, the shopper performs a series of tasks related to the activity of purchasing products from the store. These tasks are guided by basic rules such as, for instance, the ownership of a credit card. On the one hand, this rule is required as a precondition for some tasks, also subject to rules, on how to purchase products and pay for them, etc.  
On the other hand, the tool that the activity system provides to the shopper is materialized by a software artifact (the smartphone app), which must be complemented by other tools, such as a network of sensors. The shopper's role is very different from the JWO-store system's role. This specialization of the activity systems, between shopper and JWO-store system represents a diversification of tasks, i.e., what the shopper does is not done by the other agent and _vice-versa_. In activity theory language, this is defined as the division of labor.  
However, although this apparent _\"division\"_ seems to separate the roles of each one in terms of interaction, the shopper has a relationship with the JWO-store system, so they also constitute a community.  
In this way, and using the same general analysis for each participating agent, it is possible to describe the systems (triangles) and how they take part in an NoA. This NoA represents an ecology in which the different activity systems _\"live\"_ and interact. The detailed activities for each particular subject and their corresponding elements are shown in Tables 1 and 2 respectively.  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Element** & **Description** \\ \hline
**Subject:** & _Shopper_ \\
**Object:** & _Get products_ \\
**Tools:** & _Smartphone/app_ \\
**Rules:** & \\  & R1: (_Must_) _Have a credit card_ \\  & R2: (_Must_) _Scan the app to get into the store_ \\  & R3: (_Can_) _Pick up items from the shelf_ \\  & R4: (_Can_) _Put items back on the shelf_ \\  & R5: (_Must_) _Pay full purchase amount_ \\
**Division of Labor:** & _Shopper: Purchases items. Pays the bill_ \\  & _JWO-store system:_ \\  & _Protect shoppers_ \\  & _Improve the shopping experience_ \\
**Community:** & _JWO-store system_ \\  & _Other shoppers_ \\  & _Store staff_ \\ \hline \hline \end{tabular}
\end{table}
Table 1: Key Activity System for the Shopper.  
Graphically, the activity triangles of the subjects involved can be represented (simplified), as in Figure 3. In the figure, the individual activities connected constitute an initial NoA. The details of the tools, rules, community, and division of Labor have been described in Tables 1 and 2 and have not been included in Figure 3.  
However, it must be assumed that all the elements are present there and take part, in parallel, in other interactions and interrelations with the elements of other activity systems in the ecology.  
\begin{table}
\begin{tabular}{l l} \hline \hline
**Element** & **Description** \\ \hline
**Subject:** & _JWO-store system_ \\
**Object:** & _Get profit_ \\
**Tools:** & _Cameras/sensors/Al/computer vision_ \\
**Rules:** & R1: _(Must) Verify shopper’s entry_ \\  & R2: _(Must) Activate tracking sensors_ \\  & R3: _(Cam) Provide product information_ \\  & R4: _(Must) Check if an item is picked up from a shelf_ \\  & R5: _(Must) Check if an item is put back on a shelf_ \\  & R6: _(Must) Calculate purchase amount_ \\  & R7: _(Must) Verify the shopper’s exit from the store_ \\
**Division of Labor:** & _Shopper: Purchases items. Pays the bill_ \\  & _JWO-store system:_ \\  & _Check shoppers in and out_ \\  & _Calculate purchase amount_ \\  & _Report inventory status_ \\
**Community:** & _Other shoppers_ \\  & _Store staff_ \\ \hline \hline \end{tabular}
\end{table}
Table 2: Key Activity System for the JWO-Store System.  
Figure 3: Representation of the NoA for the scenario proposed (simplified form).