Research Outline
In the Great East Japan Earthquake of March 11, 2011 and the Fukushima Daiichi Nuclear Power Station incident that followed, the word “unexpected” was used often. In order for our society to be sustainable, it must be able to cope flexibly to various external events. In this regard, we must focus not only on systems that do not break, but also on the important concept of how quickly they can recover if they do break. The word resilience refers to the capability of flexibly recovering even if there is a temporary loss of function in response to a major change in the environment.
In the long history of the earth, living organisms have responded to many events. Even when certain species became extinct, other species filled the gap to maintain the ecosystem. Not only living organisms, but also human-made items such as the Internet, social systems such as economies and finance, and companies and organizations all maintain their activities by responding flexibly to external disturbances.
Do these resilient systems have any common characteristics? Can we construct a body of knowledge for designing and operating resilient systems based on such characteristics, or on scientific principles? Through our researcher network spanning a wide range of fields, we will answer these questions. In addition, with this body of knowledge, we should be able to make human societies safer and more sustainable. (Project Director: Hiroshi Maruyama (Institute of Statistical Mathematics))
Project Objectives
In this project, “Systems Resilience,” our ultimate goal is to construct a body of knowledge (BOK) for designing and operating resilient systems. To do so, we believe that we must have the following three items.
- A definition and evaluation standard for resilience
- A systemized catalogue of various resilience strategies
- A methodology and best practices for designing and operating resilient systems
Project Framework
Our first task in this project is to collect insights on resilience from the widest variety of fields possible and synthesize them. In this way, we will elicit a clearer definition of what resilience is, and metrics for it. At the same time, we will formularize the insights we obtain in an executable computation model as an approach for shedding light on the essence of resilience. Our project will therefore proceed with research on the following four subthemes.
Introduction of Subthemes
1. Resilience integration strategy
We are not interested in small ordinary disturbances. We can handle small disturbances adequately using well-known methods such as control engineering or reliability engineering. Of the two aspects of resilience, this corresponds to the concept of resistance.
Meanwhile, we are unable to cope well with rare massive events such as the Great East Japan Earthquake using the concept of resistance only. This is because the cost of resistance would become extremely high. For example, building a costal defense barrier high enough to withstand the tsunami that devastated the Tohoku area after the earthquake would be unrealistically expensive, even if it were possible from an engineering perspective.
Economist Kei Takeuchi in his book, “What is Coincidence—Its Positive Meaning,” says that with respect to extremely rare events, we should assume they will not happen, and if they do occur, we should reallocate their negative effects in society. We must consider the optimal meta strategy on how we should distinguish between the strategies of resistance and recovery.
In this subproject, we aim to create a meta strategy index for how much cost should be respectively allocated to resistance and recovery in order to build a resilient system. (Research Leader: Hiroshi Maruyama (Institute of Statistical Mathematics))
2. Resistance in living organisms
Biological systems need to have built-in robustness to enable them to endure constant exposure to stress and repeated dangerous situations. We focus on the following three aspects in biological systems, which appear mutually contradictory at first glance, to explain the resistance and recovery mechanisms in living organisms. (Research Leader: Hiroshi Akashi (National Institute of Genetics)
- Environmental Adaptation in Ecological Genetics
Ecosystems are constantly exposed to environmental changes and external disturbances, and it is thought that their genetic diversity and adaptation mechanisms contribute to their survival in the face of external disturbances to the environment and dangerous situational changes. We will attempt to illuminate these mechanisms by clarifying the relationship between ecosystems and their genes.
- Deleterious Mutations in Population Genetics
Mutations are considered to produce genetic diversity, but mutation itself can sometimes be a significant threat to a biological species. Genetic analysis of large populations has shown that deleterious mutations occur constantly in the genes of various living organisms. When the number of individuals of a certain species is relatively small, a deleterious mutation can spread throughout the entire species and reduce the degree of adaptation of the population. On the other hand, when living organisms have a fitness function that follows the law of diminishing returns, this could serve as a protection mechanism against deleterious mutations. We aim to investigate this hypothesis. - Biological Systems in Extreme Environments
It is not necessarily the case that only ecosystems that have diversity are stable. In environments that are harsh for living organisms, such as Antarctica, a very limited number of biological species are known to maintain a stable ecosystem. We will seek to shed light on the mechanisms involved.
3. Resilience in Social Systems
Order formation in social systems is usually considered to be carried out in a top-down manner by the state through the definition of a system of laws. However, in complex modern social systems, in order to respond more flexibly to unexpected events, it is necessary to review this top-down order formation hypothesis. Recognizing that only the people suffering because of a problem possibly have the best knowledge to solve it; it is necessary to introduce bottom-up type rule formation that can respond flexibly to changes in a situation.
Our focus is on the concept of co-regulation, which is receiving more emphasis recently, particularly in Europe. Co-regulation aims at a public-private collaborative system formation method, where regulating for new social problems is carried out by prioritizing a response based on voluntary regulation by corporations and other operating in the field concerned, with the government compensating for risks and imperfections.
In this subproject, we look mainly at fields of the legal system such as cyber security and privacy protection and aim to construct a methodology for bottom-up type order formation using co-regulation to realize resilient social systems. (Representative Researcher: Hitoshi Okada (National Institute of Informatics))
4. Resilience Computation Model
To evaluate the resilience of complex and large-scale systems, it is essential to have a computational methodology for revealing the various dynamic characteristics in a general mathematical model. We will focus particularly on large-scale systems, treating them as various network models (Boolean, Constraint, Bayesian networks, etc.) to devise modeling techniques that efficiently express dynamic changes in the system composition with respect to unexpected events.
Further, in the network model, we aim to construct a computational theory for analyzing dynamics, such as 1) sensitivity to external disturbance and system variables, 2) impossibility of predicting system status, 3) introduction of the concept of grammatical and semantic gap between system states, 4) network configuration renewal to satisfy soft constraints as far as possible, and 5) multipurpose optimization problem with multiple agents. In doing so, we aim to clarify the general principles for designing resilient systems. (Research Leader: Katsumi Inoue (National Institute of Informatics))
Research View 025
Harnessing the Power of Resilience
[Systems Resilience] Hiroshi Maruyama (Professor, The Institute of Statistical Mathematics)
Research View 017
Evolutionary Strategies of Diverse Wildlife
[Systems resilience] Jun Kitano (National Institute of Genetics - Project Associate Professor)
Research View 001
How Should Science Deal with the Unexpected?
[Systems Resilience] Hiroshi Maruyama (Assistant Director and Professor, The Institute of Statistical Mathematics)