Due to the space limitation, we defer explanation and discussion of the detailed

development procedures and scientific significance of the SS ontology itself to another paper. The main focus of the research presented in this paper is to create a rationale for SS knowledge structuring and apply ontology engineering to develop a knowledge system that facilitates addressing ‘what to solve’ and ‘how selleck chemicals llc to solve’ for SS. Reference model for knowledge structuring in sustainability science Requirements for knowledge structuring in sustainability science First, we must answer the question “How can we identify necessary conditions and functions for knowledge structuring in SS as development requirements?” (Berztiss 1992). The requirements can be described from two perspectives; one related to the knowledge architecture itself and the other concerning the functions required to support users. The first perspective can be examined from three sub-perspectives: ‘whenever,’ ‘whatever,’ and ‘whoever.’ By ‘whenever,’ we mean that structured knowledge should be reusable. Thus, reusability is one of the requirements for SS knowledge structuring. ‘Whatever’ implies that structured knowledge should be applicable to as many different

domains as possible, not just to a specific domain or discipline, due to the multidisciplinary and see more interdisciplinary characteristics inherent to SS (Komiyama and Takeuchi 2006). This feature should be interpreted as versatility, which check details is also required for SS knowledge structuring. As Hasumi (2001) points out, the concept of sustainability should be understood by its diversity due to the complexity of the problem it treats. This means that, while seeking versatility, one often enacts simplification; however, it is also necessary to maintain sufficient diversity and complexity to characterize the original problem. Versatility for SS knowledge structuring is, therefore, needed to express a situation without losing its diverse contents, while using

a set of rules that are as simple as possible. By ‘whoever,’ we mean Tenofovir clinical trial that anyone should obtain the same result, as long as he or she traces the same structuring process and procedures. Such reproducibility is required to verify the structuring process, as is the case with any scientific procedure. Since SS treats evolving problems that require dynamic redefinition of the problem’s domain by consistent networking of knowledge and actions, the SS knowledge structure must be extensible in order to meet unpredictable future changes of the domain. As knowledge changes over time, its representations must adjust accordingly (Choucri et al. 2007). Thus, extensibility, which includes adjustability, is the fourth imperative of SS knowledge structuring. The second perspective relates users, who are the main actors, with their actions for SS. The larger the number of people who share the structured knowledge, the larger the common base of SS becomes.