Logistic systems show complexity

• It is a geographical territory composed of urban areas and of logistic structures.
• These structures support organized flows of goods which mainly move between the urban areas, forming the logistic corridor.
• The goods enter and leave the system through well-known access nodes.
• Different constraints (spatial, economical, political, or ecological) act over the system.
• There are numerous and heterogeneous actors (importers, exporters, freight forwarders, logistic providers,...). Their behaviors and interactions with each other allow to organize the flows of goods. They are auto-organized.

Problematic

• We want to understand how actors with different goals, are organized around all the logistic infrastructures to manage flows of goods despite all the constraints of the system.
• We are looking for an individual-based model which can reproduce the working of a logistic system thanks to the simulation.
• And then we could test different scenarios on this simulation to understand how the local decisions impact the system.

A complex system approach

• An agent-based model which represents each actor and infrastructure thanks to autonomous and reactive entities.
• These agents have predefined rules which describe how they behave and interact together according to their perceptions of the environment and to their needs.

• A dynamic graph represents the transportation network.
• We can follow in real time each vehicle agent and observe the traffic evolution.

Implementation

• We implemented the model as a step-by-step simulation into the agent-based simulation platform GAMA.
• We use real data on the Seine axis to check its validity and to make measures.
• The Seine axis is mostly represented by the road (around 90% of the traffic is by road).

How do logistics service providers (LSPs) select a port?

• $F_{ij}$ is the force of attraction between the port $i$ and the LSP $j$.
• $A_i$ is the attractiveness of the port $i$. This parameter represents the competition between ports: a higher attractiveness value means that the port is more competitive than another one.
• And $d_{ij}$ is the distance between $i$ and $j$.

Effects of port attractiveness on traffic

To sum up

• We proposed an agent-based model and dynamic graphs to represent a logistic system
• The implementation has been done thanks to the GAMA platform and it uses data on the Seine axis.
• It allows us to observe the effects of a local parameter on macro properties: here the port attractiveness on the traffic evolution.

Perspectives

• We want to implement the multi-modality.
• We want to study the interaction network in order to detect special communities of actors.