# Linked Data Aware Agent Development Framework for Mobile Devices
## 4 Case Study and Discussion
### Collaboration Diagram for the Case Study  
The auction application which has been developed as a case study using the LDAF-M platform, is in fact a multi-agent system consisting of a number of agents. Each of these agents interacts with each other as well as with the LDAF-M platform's main components. We illustrate these interactions in a collaboration diagram which is given in Figure 7.  
Figure 7: Collaboration diagram for the agent based auction application. Each numbered interaction in the collaboration diagram is explained below. Please note that initially the agent platform is initialized, the AMS which will keep the agent identifiers and manage agent life cycle and the DF which is like a yellow page service are created. These steps are not shown for the sake of simplicity. 1: After the auction application has begun to execute on the mobile device that would serve as the server within the context of the developed application, an administrator agent is created. Upon creation, the administrator agent registers with the Directory Facilitator (DF) so that agents that are going to be created in future within the context of the auction application can discover it. The DF information console is shown in Figure 8.  
2: The administrator agent obtains the login information belonging to all of the system's users from a data resource. In our case, the administrator agent obtains this knowledge from the RDF documents that we have already recorded to Freebase and then internalizes that data in its belief base using the graph data structure introduced in Section 3. 3. On the client side, users that want to use the auction system need to create a login agent. Upon creation, the login agent asks the DF for the administrator agent. 4: The DF sends the information about the administrator agent to the login agent. 5: The login agent transmits its user's login information to the administrator agent. 6: If the authentication process ends with success, the user receives a login success message. 7: The login agent terminates after successful login. 8: After successful login, client agents which represent participants in an auction are created. Then they register with the DF. 9: A client agent obtains the data about the products that it is going to sell or buy from the RDF documents residing in Freebase. After the client agent parses that data, it maps the parsed data into the LDAF-M's graph based data structure to record them as its beliefs. 10: The client agent asks the DF for the administrator agent of the application. 11: The DF sends the information about the administrator agent to the client agent. 12: The client agent communicates directly with the administrator agent to send it a request for starting an auction for a product that it decides to sell. The client agent repeats sending this request for each of the products that it wants to sell. 13: After processing this request, the administrator agent creates an auctioneer agent which is responsible for managing the auction for that specific product. 14: The auctioneer agent asks the DF for the client agents registered. Figure 8: The Directory Facilitator (DF) information console. 15: The DF sends information about all the client agents which registered with it. 16: The auctioneer agent sends invitation messages to all of the client agents (other than the client agent which is the seller) asking them whether they prefer to participate in the auction for that specific product or not. 17: A client agent evaluates this invitation considering the beliefs in its belief base and makes a decision as a result. If it decides to participate in that auction, it notifies the auctioneer agent about this decision. 18: Each auctioneer agent registers itself with the DF for only a pre-specified time period. When the time period for an auctioneer agent completes, its registration record is removed from the DF.