Machine & Infrastructure Replacement Decisions
Stochastic and multi-stage optimization models for machinery and capital asset replacement under uncertainty.
Problem Space
Replacement decisions for capital-intensive assets involve long-term uncertainty, economic tradeoffs, and operational risk. Traditional replacement models often assume fixed planning horizons or deterministic conditions, which rarely reflect real-world environments.
The core challenge is deciding when to replace machinery while accounting for uncertainty in demand, cost, and operational conditions.
Approach
This research develops:
- Multi-stage stochastic programming models
- Replacement models under horizon uncertainty
- Integrated models that include shipping and logistical considerations
- Life-cycle cost analysis frameworks
The models explicitly incorporate uncertainty rather than treating it as an afterthought.
Impact
These frameworks improve long-term capital allocation and reduce risk exposure in industries such as construction, manufacturing, and infrastructure management.
They shift replacement analysis from static cost comparison to dynamic system-level optimization.
Selected Publications
- Seif, Shields & Yu (2019), The Engineering Economist
- Shields, Seif & Yu (2019), International Journal of Production Economics
- Seif & Rabbani (2014), Journal of Quality in Maintenance Engineering
Publications
Parallel machine replacement under horizon uncertainty
Construction projects usually get delayed for several time periods. When the planning horizon of a project is extended, projections for purchase and salvage of …
Parallel machine replacement with shipping decisions
In this research, the Parallel Machine Replacement Problem is adapted to include shipping decisions between demand sites. The formulation arises from an applica…
Component based life cycle costing in replacement decisions
This paper presents a component-based approach to life cycle costing (LCC) in parallel machine replacement problems. Failure rates of machine components are inc…