Life Cycle Evaluation under Uncertain Environmental Policies Using a Ship-Centric Markov Decision Process Framework.

Abstract

A novel design evaluation framework is offered to improve early stage design decisions relating to environmental policy change and similar non-technical disturbances. The goal of this research is to overcome the traditional treatment of policy as a static, external constraint and to address in early stage design the potential disruptions to performance posed by regulatory policy change. While a designer’s primary purpose is not to affect policy, it is the responsibility of the designer to be cognizant of how policy can change, of how to assess the implications of a policy change, and of how to deliver performance despite change. This research addresses a present need for a rigorous means to keep strategic pace with policy evolution.

Use of a Markov Decision Process (MDP) framework serves as a unifying foundation for incorporating temporal activities into early stage design considerations. The framework employs probabilistic methods via a state-based structure to holistically address policy uncertainty. Presented research enables exploration of the performance of a design solution through time in the face of environmental instabilities and identifies decisions necessary to negotiate path dependencies. The outcome of this research is an advanced framework for addressing life cycle management needs that arise due to policy change, as judged from a life cycle cost perspective.

Original metrics for evaluating decision paths provide insight into how the timing, location, and confluence of disturbances impact design decisions. Development of the metrics is driven by a desire to communicate the design-specific characteristics of a strategic response to policy change. Quantifying the amount and type of uncertainty present, changeability afforded, and life cycle changes exercised offer points of comparison among individual design solutions. The knowledge gained from path-centric measurements enables an enhanced ability to characterize design lock-in. Principles and metrics borne out of the design evaluation framework are validated through two ship design examples related to ballast water treatment and carbon emissions.