agent-based modeling

Ecological and social science researchers have long faced the challenge of modeling the intrinsic complexity of socio-ecological systems. A popular approach to understand and investigate these systems is agent-based modeling, which has been used not only in ecological sciences but in many other disciplines over the years and has become a widely used tool nowadays. Despite the importance of this modeling approach, there was no standard protocol to make and present these models by 2006. Hence, several expert modelers who covered a wide range of areas in ecology suggested the ODD protocol (Overview, design concepts, and details) as a standard for describing individual-based models (e.g., agent-based models) in 2006. After that, some providers of the first version of the ODD protocol have developed an updated version of this protocol in 2010 to resolve problems and ambiguities of the original version, as an alternative for the previous version, by reviewing research that used this protocol. Then, considering the fundamental role of human decisions in agent-based modeling, a new version of this protocol named ODD+D was introduced in 2013, specifically for this modeling approach. The purpose of the ODD+D protocol was the development and modification of the ODD protocol to create a standard for describing agent-based models so that it can consider human decision-making within itself. Due to the importance of applying this protocol in the structure of agent-based modeling studies, the present research introduces the ODD protocol, reviews its evolution over recent years, and addresses the detailed description of different versions.

Growing population of the cities along with the desire for better welfare and health has increased the water demand. On the other hand, many cities are located in the arid and semi-arid regions with the low rainfall and renewable water resources. Therefore it causes the water crisis. Shiraz is one of the metropolises that is facing this problem and in the warm seasons of the year experiences the drop in water pressure and water outages. Increasing the water supply, regardless of demand management, will exacerbate the crisis. Water pricing has been also one of the most important concerns of policymakers in demand management. Given the importance of this issue and also the role of social interactions among the consumers and the neighboring community network on the water consumption behavior, the present study concentrates on providing an agent-based framework for examining the water demand and changes in consumption behavior (diffusion process). The model has been calibrated for domestic water consumption in Shiraz for the years 2005-2019. Price increase scenarios (for all or only part of the consumers) as well as granting free branches have been simulated for the years 2020-2032. The results show that small increases in water prices do not have significant effect on consumption and cooperative behavior trend. Also, giving free branching to some consumers will intensify non-cooperative behavior among other consumers and increase the consumption sharply.

Application of agent based model in simulation of stakeholder’s behavior is slightly a new method for modeling of complicated systems that include autonomous agents interacting with each other. Recent numerical achievements have made the applications of agent based models possible in various fields. These applications range from modeling of human progress and destruction of past civilizations to modeling of complexities in water resources/consumption systems. In this article foundation of agent based modeling is defined, related tools in this field is introduced and their application in water resources management is clarified. The use of such models provides social interactions simulation. Integration of such simulation models with water resources simulation models helps to make and improve the reliability of decision support systems in water resources management.