Abstract
Since the start of the 3rd millennium, sustainability has emerged as a key element for mankind’s development; if we use the traditional definition (derived from studies coming from the 1980s), a sustainable development is expected to meet the needs of the present without compromising the future, and guaranteeing the sustainable development of our society is still one of the main problems that humans have to face.
It is evident that we need simulation to investigate the future, considering that our traditional sense, perception and forecasting capabilities are characterized by a time horizon too limited to evaluate the future effects of our current decisions in strategic areas such as the environment, finance, energy and social issues; obviously these are just some of the elements to be considered in terms of sustainability, and there is a large spectrum of opportunities to develop modeling and simulation (M&S) in this sector.
Already in early 2001, just looking at the economic crisis affecting North America months before the September 11 terrorist attack, we witnessed large-scale employment layoffs and social impacts that introduced doubts about the effectiveness of previous economic decisions. From this point of view, it is interesting to think about the main technological issues addressed even during the end of the 2nd millennium, of which, among others, the Millennium Bug, enterprise resource planning and multicurrency management were considered critical issues with huge investments from private and public sectors; the scope of some of these challenges was overestimated, while it emerged that other real challenges were very hard or even impossible to face in short/medium terms due to a lack of resources and capabilities.
Obviously, this situation is not uncommon even in other time periods, and we are used to failing to predict the future and to properly estimate world expectations; however one interesting issue emerging from the 3rd millennium is the fact that sustainability is a major challenge that we cannot face just by improving prediction capabilities and by achieving short-term results: The inertia of global challenges is usually so big that it is nearly impossible to react with available resources, and a long-term plan is required to mitigate its effect.
During the first decade of the 3rd millennium this issue was further reinforced, and we realized that both in finance and in politics our challenges were often too big to solve. The advent of one of the biggest financial crises in the modern age largely overshadowed the forecasting and mitigation capabilities of the world economies, and concurrently, in South Asia, the limitations of the modern military apparatus in addressing comprehensive scenarios was clearly demonstrated. If we think both to remote ages and the recent past, it is evident that these concepts were well known, and even at the time, nobody was expected to be able to regulate economic cycles or to solve political instability just by using force. The technological advances of the information age had generated an illusion of omnipotence over many areas around the globe, and some people believed that knowing the problem ahead of time was enough to set up quick solutions without considering that the dimension of the problem could bypass our capabilities.
It is important to outline, however, that new millennium technologies have introduced positive and innovative concepts such as mobility and crowd-sourcing paradigms that are currently moving forward toward new and exciting development opportunities in very different areas. Moving to the simulation community, we realize that the M&S world is being driven concurrently by the need to face the new challenges and by the opportunities from enabling technologies and methodologies; due to these reasons it is not surprising that sustainability is becoming a major subject and that several M&S events and workshops have been established. This process allows the creation of communities focused on how M&S can contribute to sustainability; a very good example is represented by the International SESDE (Simulation for Environment, Sustainable Development and Energy) Workshop that is part of the International Multidisciplinary Modelling & Simulation Multiconference (I3M). In addition, new models and skills in sustainability are currently regarded as key competencies by major institutions, companies and organizations, and this element is now an additional crucial requirement to be considered in developing new businesses and systems.
As part of the simulation community, we are used to addressing these issues by quantitative models, developing new simulators, methodologies and approaches able to cover these new areas; so in similar way in this Special Issue we present different innovative research addressing sustainability from diverse points of view. The aspects proposed focus on very different issues, therefore the common approach is guaranteed by considering sustainability as a key performance index.
From this point of view it is interesting to think about the evolution of health care around the globe and the different perspective introduced by sustainability. A study this issue by Sokolowski et al focuses on a specific but critical element: blood resources and potentially innovative approaches such as patient blood management as an alternative to traditional transfusion practice. As always happens, this specific solution needs to be evaluated and tested considering the boundary conditions and future scenarios, so there emerges the necessity of using simulation as an investigative tool to support health care decision makers in properly evaluating different alternative solutions to be made not only today, but that will have a deep impact on the future. In this context, the potential to use simulation as an educational aid and a training support for the introduction of new policies in this sector is evident; indeed, the current health management confirms the need to extensively use modeling and simulation in this area, in effect representing a fast-developing sector for M&S.
Another sector that is radically changing today is production systems; in this area, social as well as environmental impacts have demonstrated that short-term analysis can lead to completely wrong solutions. A related study by Jiménez et al in this issue investigates the idea of using simulation models to determine the environmental impacts of the product according to the decisions made in the production systems. The case proposed, related to the wine sector, is very interesting, considering the drastic evolution in wine production, where new countries are emerging as top-quality and large-quantity producers. It is evident that this study can lead to many other industrial sectors and that the metrics evaluated through simulation can be a powerful tool for guaranteeing new production system sustainability.
Thinking about sustainability, transportation and energy are probably the two major application areas based on public opinion, so it is not surprising to have two studies addressing these sectors in this special issue. In transportation the discussions are usually related to an urban context, therefore it is interesting to think that in future decades we expect a real revolution in air mobility. Thanks to new technologies, the extensive use of drones for cargo as well as the possibility of bypassing air corridors, we are expected to observe a complete change in this area.
A related study by Piera et al in this issue addresses possibility of M&S to define requirements for future solutions for connecting air traffic controllers, handling operators, airlines and airport managers. These elements, already very important today, will in the future become critical, so the need to evaluate the performance of new systems and their sustainability indexes via simulation is evident.
In the energy sector, sustainability is almost everywhere, touching sources, use, transmission, saving, etc. A study by Adetona et al focuses on the creation of new investment planning models to be used in networks for the wholesale electricity market in order to guarantee sustainability, reliability and availability.
The special issue addresses also new algorithms and methods devoted to support optimization and resource management in complex systems; indeed the issue of sustainability provides us with complex challenges, in which multiple factors are required to be addressed concurrently in order to achieve multi-objective results touching diverse areas such as the economy, social science, profitability, environmental impacts, etc. From this point of view a study by Tao et al is included that focuses on a new multi-agent optimization system devoted to guaranteeing effective and efficient multi-objective combinatorial optimization by adopting multiple evolutionary strategies. Another study by Muñoz et al combines discrete event simulation with fuzzy logic to guarantee distribution of limited resources in order to solve complex problems; the validation of the approach in this case is related to health care management, therefore in all the proposed examples, simulation emerged as the most proper science to address these issues, and it represents the enabling methodology to study sustainability in complex systems.
It is important to outline that sustainability is a challenge that requires multicultural teamwork. In this area, we expect that researchers, professionals and politicians with different backgrounds, and often representing different groups of interests, combine their efforts; due to these reasons, the current special issue is an important opportunity to diffuse these concepts and to develop further cooperation on this subject.