Systems modeling in the naval domain

Abstract

The need for relating stakeholders with requirements and the need for systems modeling are the main drivers for this thesis. Relating stakeholders with requirements is beneficial in order to balance the interests of all stakeholders associated with complex design projects. The variability in types of stakeholders and information abundance in current projects are the main causes of the difficulty in establishing this relationship. The need for system modeling is part of the transition towards Model Based Systems Engineering (MBSE), realizing a single source of truth and improving efficiency by better communication between all involved stakeholders.

At first, a breakdown of requirements management processes is presented, followed by an exploration of stakeholders within the naval domain. Requirement management processes are extensive, elaboration of requirements is the more important step during this thesis. Structuring the requirements as part of the elaboration is based on an OFP-decomposition, where `O' stands for Operational, `F' for functional and `P' for physical.
The complexity of stakeholders is tackled by an analysis which consists of the main steps: identification, differentiating \& categorizing, investigating relationships and prioritization. Prioritization of stakeholder is based on four attributes: power, interest, urgency and legitimacy.
Applying MBSE by incorporating systems modeling demands a selection of the main pillars, being a method, tool and a language. The method during this thesis is ARCADIA, preferred by DAMEN due to the compatibility with the software `Capella'. The language is chosen to be the NATO Architectural Framework (NAF). System modeling is currently in a state of implementation at DAMEN Naval, therefore, this research aids in the continued development of their processes.
As mentioned, the NAF is used as a language to model the stakeholder`s concerns in a systematic way. The NAF consists out of 47 independent viewpoints, each specifying a different concerns on a specific level of detail. The representations of these viewpoints are not strict, therefore, translating these concerns into Capella was one of the first major tasks.



A method is designed to establish the relationship between stakeholders and requirements by using the NAF as a backbone. The method consists of 12 steps and inhibits an iterative character, as is common in naval ship design processes. The inputs of the method are a stakeholder analysis and a set of OFP-classified requirements, resulting in a systems architecture relating requirements with stakeholders. Creating additional non-NAF existing concerns is one of the pitfalls of the method and the presented guidelines are still creating room for error, therefore more research into this part of the method is advised.

The method has been assessed by using a Proof of Concept (PoC), a limited case study based on 2 selected stakeholders and a limited set of requirements. The requirements for the PoC were found in the Maritime Interdiction Force Operations (MIFO), displaying demands for conducting boarding and deterrence missions at sea. Concerns per stakeholder have been analysed and viewpoints were selected from the NAF. The Capella project model was used to construct the diagrams from. The result was an agglomeration of diagrams representing all viewpoints, contributing to the construction of the `best suited' systems architecture and fulfilling most of the success criteria. Relating all requirements to the diagrams has proven to be hard during the PoC and it is recommended to improve these efforts in a next iteration, as well as the use of other representation-forms instead of the diagrams common to Capella.

The subsequent step was to address the method by a case study, including more stakeholders from within the naval domain. The analysis comprised 12 stakeholders, internal and external with respect to DAMEN Naval. The concerns per stakeholder have been analysed, viewpoints selected and the diagrams were constructed by the system modelers team. This resulted in more detailed diagrams w.r.t. the PoC. The final systems architecture is capable of relating the requirements from the operational layers to the physical layers by the structured representation according to the NAF. Classification of requirements is done according to the OFP-decomposition, however further research into other classifications could prevent increasing complexity.