Policy Refinement

Layered refinement with interleaved transformations
Layered refinement with interleaved transformations

Refining policies from high level goals to enforceable specifications in asemi-automated and principled ways remains one of the most significant challenges in policy based systems. We have on two occasions attempted to tackle this challenges in collaboration with Dr Alessandra Russo at Imperial, Dr Arosha Bandara at the Open University and Dr Jorge Lobo at IBM. The first attempt wast done during the Dr Bandara’s PhD thesis. In essence, the approach followed was to treat policies as requirements and apply requirements elaboration techniques (more specifically the KAOS methodology developed by Prof Axel van Lamsweerde and his colleagues). A policy goal is progressively elaborated through patterns following the KAOS approached. When the leaf goals correspond to post-conditions of existing management operations and adductive inference process is applied to create the plan that would achieve the desired objectives. This approach is described in the following:

Arosha K. Bandara, Emil C. Lupu, Alessandra RussoNaranker DulayMorris SlomanParis FlegkasMarinos CharalambidesGeorge Pavlou: Policy refinement for IP differentiated services Quality of Service management. IEEE Transactions on Network and Service Management 3(2): 2-13 (2006).

A video demonstrating the PonderART tool set is available from here.

A second approach was then taken in a project sponsored through the USUK International Technology Alliance. In contrast to the previous approach we have followed here a more comprehensive policy formalisation that also includes time, and we have structured the refinement process as a multi-stage multi layered process. Within each layer, i.e., from a higher to a lower level of abstraction we interleave phases of action decomposition, operationalisation, analysis, solution selection and deployment (see Figure). This work was conducted with Dr Robert Craven and is described in the following publications.

Robert CravenJorge Lobo, Emil Lupu, Alessandra RussoMorris Sloman: Policy refinement: Decomposition and operationalization for dynamic domains.CNSM 2011: 1-9.

Robert CravenJorge Lobo, Emil C. Lupu, Alessandra RussoMorris Sloman: Decomposition techniques for policy refinement. CNSM 2010: 72-79.