## 3 The HADES Framework
### HADES Mission and Guidelines  
One of the objectives of HADES is to transform the berth programming methodology in multi-client terminals from linear to circular (Figure 4). In the current (linear) methodology, different agents communicate their arrival and berth planning to the port authority. That information is static and there is little opportunity to coordinate, leaving terminal operators with limited access to the information. As already mentioned, such uncoordinated arrivals often produce days of congestion (with vessels suffering delays) followed by days of underutilization with unoccupied fronts.  
To address this situation, the mission of HADES is to promote, assist, and monitor time coordination at berths in multi-client terminals, which prevents congestion anchoring situations before they occur. Although applicable to any type of operation, it is estimated that this methodology will have special impact on liquid bulk terminals, whose operations cannot usually be diverted to other fronts. The result is a dynamic circular method, where users can adjust their arrivals in light of forecasts and estimated occupation.  
The circular methodology of HADES encourages a more harmonious use of resources, promoting coordination among terminal operators, shipping agents, and port managers. HADES is conceived as a multi-agent platform, where the port authority is the owner, and the terminal operators share limited but relevant information.  
HADES:  
* Requires terminal operators to record expected future operations at target docks, including expected arrivals, required resources, and operation durations.
* Permits these operators and the port manager to visualize the forecasted quay occupation based on the previous information, and the operators to see if their projected operations would be simultaneous and, therefore, in conflict with operations recorded by other terminal operators. The aim is to promote consensual coordination in arrivals to reduce dead periods.  
Figure 4: HADES transformation of berth planning programming methodology from linear to circular.  
Periodically provides recommendations of vessel arrival time shifts to the terminal operators to reduce overall anchoring times, which may be accepted or not. Such recommendations are the output of the HADES time coordination algorithm, which jointly attempts to exploit the time flexibility in vessel arrivals and (if any) flexibility in quay allocation. The MILP optimization model prototype behind the joint allocation process is described in Section 4.
* Provides meaningful statistical information to the port authority on the efficient use of the port's resources and forecasted occupation to identify possible bottlenecks and improvements.
* Includes automatic methods to monitor the fair use of the system, identifying inefficient situations and bottlenecks. Monitoring and auditing fairness in accessing shared resources and automatically identifying misuse helps encourage proper behavior in multi-client systems. For instance, HADES is evolving to adopt a predictive system of vessel arrival times using automatic identification system (AIS) to verify the accuracy of the arrival estimates provided by users. To do so, it evaluates previous average accuracy in the operation durations estimated by HADES users.  
HADES proof-of-concept, in operation in the Port of Cartagena since July 2020, is integrated into the port management system (PMS) of the Cartagena port in an application known as INTEGRA2 [34]. This application is used by most of the Spanish Port Authorities, which would facilitate the adoption of a similar system by other Spanish ports. INTEGRA2 includes a database that records multiple aspects of port operations, including a record of past vessel arrivals and resource use. HADES automatically reads from the INTEGRA2 system and includes an alternate database, which stores the estimated future vessel arrivals and resource occupation provided by port terminal users, and other information from the application business logic.