**1. Introduction**

Requirements elicitation (RE) is a valuable process for the identification of *solution* requirements according to the need of clients of users [1]. In this chapter, the concept of *solutions* includes products, such as software systems or intangible solutions, such as data analysis. According to several authors, application domain knowledge is essential to obtain the correct and appropriate requirements. The application domain is an area where a solution is or will be used. Consequently, requirements engineers must understand, as soon as possible, the structure, the processes and the restrictions of a domain in which they are generally

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2017 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

neophytes. This knowledge belongs to domain specialists, any person possessing application domain knowledge and/or having a role in the domain. Therefore, requirements engineers must elicit the application domain knowledge from domain specialists in order to include it into a set of solution requirements. It is a complex and highly creative activity that involves intensive cognitive activities, especially when the application domain has a high degree of informality where knowledge is informally stated, partially complete, implicitly assumed, tacit and unstructured [2].

This phenomenon is presented in many disciplines such as *intelligent tailored solutions for illstructured domains, software for complex domains, intelligent tutoring systems, knowledge based systems, industrial design, among others*. In general, every necessity that requires a complex, highly creative solution, in which the requirements engineers are not a part of the application domain and need eliciting sufficient high-quality knowledge to understand the clients' need and expectations, faces this challenge [2]. Therefore, instead of focusing on the challenges of developing a requirements elicitation proposal for each of these complex areas, we have expanded the vision and generalized these domains as *informally structured domains* (ISD) [3], which is widely explained in Section 2.

In addition, solutions in ISD usually respond to clients and users' specific needs. As a result, they are diverse, consensus and unverifiable, and there are not fully defined processes to develop them. Therefore, these solutions or products must be developed according to the experience of domain specialists. These characteristics hamper the requirements elicitation process because the implications of knowledge transfer and transformation, the appropriate management of tacit knowledge and the issues of knowledge exchange must be considered.

In this context, we assume that a perspective of requirements elicitation that emphasizes the importance of knowledge management (KM) is a useful approach for addressing ISD inherent problems. KM is a discipline with the aim of enhancing an organization by sharing and managing knowledge flow among the people, taking advantage of information technologies [4]. Regarding KM in requirements elicitation is not new, but only few efforts offer a full knowledge management perspective [5].

The knowledge management strategy for requirements engineering (KMoS-RE©) [6] is a highlevel plan oriented to the transfer or transformation of knowledge. The strategy has the aim of eliciting, structuring and creating knowledge that can be incorporated into a specification closest to the needs and expectations of clients. It is especially design from a full KM perspective in order to be applied in the context of ISD. The goal of this chapter is to describe the challenges of ISD and make a critical analysis of the KMoS-RE© strategy as a serious requirements elicitation proposal to face them. The analysis is based on the experience of applying the strategy in several ISD real cases. According the valuable results, the KMoS-RE© strategy promises to be a useful tool in the requirements elicitation of solution or products, especially in disciplines that share ISD characteristics [8].

The remainder of this chapter is organized as follows: Section 2 presents a characterization of ISD in order to explain the challenges of eliciting requirements in these domains. This section also includes a wide explanation of tacit knowledge. Section 3 describes fundamental concepts of KM in requirements elicitation. Section 4 discusses the utilization of KMoS-RE© as a serial proposal to face the challenges in ISD. Finally, in Section 5, the conclusions and future works are presented.
