## 4 Simulation Models and Sustainability: Characterization
### Agent-Based Simulation
To understand the application of ABS for assessing sustainability, various aspects of ABS models have been lined up with their efficacy with regards to sustainability assessment in Table 3. Since sustainability models engender high complexity, ABS models often take a long time; therefore, they cannot give the \"quick and dirty\" solutions that simulation is frequently employed to find [74]. In such cases, DES has been used as a hybrid that outperforms the ABS in performance. Among the articles collected for this review, 21 deal with ABS in manufacturing and SC in the sustainability framework exclusively, whereas in 12 articles, ABS is used as a tool hybridized with other tools. The keyword network of these papers is shown in the Figure 13. The keyword network shows five clusters. The agent-based models have been realized using both domain-specific and general-purpose languages. Some of the domain-specific software includes spreadsheet programming tools, Mathematica, and agent-based languages such as Anylogic, MATsim, Repast,  
Figure 13: The figure shows the network of keywords used in the collected papers where ABS is utilized in sustainability assessment in case of manufacturing and SC. The network show a pre-eminence of “sustainable manufacturing” and “energy consumption”. The prevalence of “discrete event simulation” points to frequency of the two simulation techniques being hybridized together. \begin{table}
\begin{tabular}{p{56.9 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Criteria** & **ABS** & **Effects on Sustainability Assessment** \\ \hline Approach & Bottom-Up & Action of agents result in population wise changes making possible sustainable emergent behaviors, e.g., sustainable supplier populations [128] \\ \hline Object & Agent & The environmentally aware agents make possible human thinking and model for social processes [129]. ABM consolidates irrational choices driven by socio-economic and cultural components. \\ \hline Feedback & Implicit & Integrate the awareness of the environmental impact of agents choice to their decision-making process. Incorporated in number of sustainability studies, e.g., in coupling between LCA and ABS [56]. \\ \hline Space/Time & Discrete/Continuous & ABM used to explore spatial and temporal dynamics for environmental awareness. Market dynamics to assess green product design impacts [56] \\ \hline Predictive power & Highest & Agent behavior prediction is highest among the three in ABS. Sustainability assessment may further augmented with ML algorithms, big data, and neural networks, e.g., green SC [130], sustainable intelligent manufacturing [131]. \\ \hline Abstraction level & Micro-Meso-Macro & ABS is capable of modeling sustainability at all the three levels from the shop floor to national carbon trade, e.g., carbon trade [132], sustainable industrial symbiosis [133], and closed loop production planning [42] \\ \hline Scope & Operational-Tactical-Strategic & Due to its functioning at both detailed level and aggregated level is used at all the three levels, while incorporating both qualitative and quantitative, ABS exhibits multi-granularity. Resource sharing [134], industrial symbiosis [133], and investment efficiency [123] constitute the three temporal levels. \\ \hline Data & Quantitative \& Qualitative & The data magnification in ABS is highest among the three, incorporating both costly factory floor measurements and delphi-style information. \\ \hline Use-case & Emergent phenomena, adaptive situations, proactive, and reactive behaviors & Owing to greater computing power ABS is used to model to high accuracy sustainability transitions, e.g., socio-technical transitions [135] \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Major aspects of ABS and their efficacy with regards to modeling sustainability. MASON, NetLogo, and Swarm. In addition to these, numerous open-source and free software is available as well--a detailed list with their application is indicated in Table 14.