
to be used for parcel storage, aiming to maximize rev-
enue.
Building on these advancements, the Green Share-
a-Ride Problem (Green-SARP) was proposed by
(Elkout and Belkahla, 2022) to address environmen-
tal concerns. Green-SARP combines the principles of
SARP with those of the Green Vehicle Routing Prob-
lem (GVRP), incorporating Alternative Fuel Vehicles
(AFVs) and the need for refueling at Alternative Fuel
Stations (AFS). This formulation aims to reduce the
environmental impact of shared mobility while main-
taining operational efficiency.
In 2023, (Elkout et al., 2023) introduced an en-
hanced Simulated Annealing algorithm with a Cor-
rection Mechanism (SA-CM) to solve Green-SARP.
Their experimental results demonstrated that SA-CM
could produce high-quality solutions close to the
optimal results obtained by CPLEX, outperforming
CPLEX for instances with more than 10 requests.
These findings highlight the potential of heuristic-
based methods to solve complex urban transportation
problems efficiently.
This innovative problem Green-SARP was first in-
troduced by (Elkout and Belkahla, 2022), by leverag-
ing the flexibility of AFVs and integrating AFS nodes
into the route design, the Green-SARP ensures the
sustainability of urban transport systems while meet-
ing the demands of modern shared mobility.
In this paper, we introduce a simultaneous Sim-
ulated Annealing-based Crossover within a Multi-
Agent model (SAC-MA) to solve Green-SARP. We
conduct computational experiments to assess the per-
formance of our approach, utilizing newly modified
data instances, and demonstrate its efficiency com-
pared to a Simulated Annealing algorithm (SA).
2 SIMULTANEOUS SIMULATED
ANNEALING-BASED
CROSSOVER WITHIN A
MULTI-AGENT MODEL
Simulated Annealing is a probabilistic meta-heuristic
algorithm, it is based on a natural technique that sim-
ulates the cooling of a group of heated atoms us-
ing an analogy to thermodynamics, a process known
as annealing (Kirkpatrick et al., 1983). Simulated
Annealing accepts search movements that temporar-
ily produce degradation of an existing solution to a
problem (Kirkpatrick et al., 1983). Simulated An-
nealing (SA) is a local neighborhood search that re-
quires exploring the search space and accepting so-
lutions with some probabilities (Davtyan and Khcha-
tryan, 2020). An artificial system composed of a
population of autonomous agents is called a multi-
agent system, in order to achieve their shared goals
the agents work cooperatively. Additionally, a multi-
agent system is a computational system in which two
or more agents cooperate, compete or combine their
efforts to accomplish some individual or group objec-
tives (Ferber, 1999). In this work, we propose a new
simultaneous Simulated Annealing-based Crossover
within a Multi-Agent model (SAC-MA) for solving
Green Share-A-Ride Problem. In addition, the fact
that Green-SARP is an NP-Hard problem, so the use
of a multi-agent system allows distributed and simul-
taneous processing, which are very complementary.
The multi-agent system is composed entirely of in-
teracting agents. Each agent can communicate, coor-
dinate and cooperate with other agents to complete a
common aim. It consists of two classes of agents: A
master-Agent (MA) and a set of Simulated-annealing
Agent (SimA) , where the MA agent is the Master of
its society and the SimA agents are its Workers/Sub-
agents. The figure 1 represents the proposed SAC-
MA approach.
2.1 Master Agent
It is the one who interacts with the user, the
master-agent (MA) receives the number of Simulated-
annealing Agents to create all parameters for the Sim-
ulated Annealing-based Crossover algorithm. It is
responsible of creating Simulated-annealing Agents
(SimA) based on the input number given by the user.
Then the MA generates an initial population with
different dynamic lists based only on pickup nodes.
Noting that the number of dynamic lists depend of
the number of the Simulated-annealing Agent given
by the user. So, the MA agent provides for each
worker-agent its necessary information such as the
agent identification (as an autonomous agent and also
as a system member), its dynamic list solution from
the initial population and the parameters for the Sim-
ulated Annealing-based Crossover algorithm. If the
stopping criterion is attained, the MA agent chooses
the best solution from the last solutions received from
Simulated-annealing Agents and displays it as the
global solution for the problem.
2.1.1 Solution Representation
The Green-SARP involves a depot, a set of requests,
and a set of AFS nodes. The answer to this prob-
lem provides 3 travels with 3 AFV each having a 60-
gallon fuel capacity and a consumption rate equal to
0.2.
Simultaneous Simulated Annealing-Based Crossover Within a Multi-Agent Model for Solving the Green Share-a-Ride Problem
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