PhD Oral Exam - Nima Moradi, Information and Systems Engineering

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Last-mile delivery is the most expensive and environmentally intensive segment of urban logistics, and its growth alongside electronic commerce has intensified pressure on operators and cities to adopt more sustainable and efficient delivery technologies. This thesis develops mathematical models and scalable optimization methods for sustainable last-mile parcel delivery systems that center on electric vehicles and three complementary auxiliary technologies: autonomous delivery robots, electric cargo bicycles, and mobile parcel lockers. Across four related optimization problems, each formulated as a compact mixed-integer linear program and solved through a tailored matheuristic that embeds an exact optimization component inside an adaptive large-neighborhood search, the thesis studies how routing, customer assignment, synchronization between echelons, battery and energy feasibility, and customer service requirements should be optimized jointly rather than sequentially. Each problem is validated through exact comparison on small instances, benchmarking against a commercial solver and existing methods on large instances, and reduction to an established benchmark from the literature, yielding numerous new best-known solutions and a consistent feasibility advantage over exact solvers at scale. Beyond these four individual studies, the thesis reports a purpose-built comparative computational case study that places five second-echelon technologies, including a conventional diesel baseline, on an identical network and customer population under one shared cost-accounting framework, across ten operating scenarios and a focused single-zone comparison. This case study demonstrates that whether a technology's labor can be shared across vehicles, rather than any difference in vehicle capacity, speed, or travel cost, is the most consistent driver of total delivery cost, that a robotic delivery technology's apparent advantage in a small, restricted zone does not generalize to a full urban deployment, and that minimizing cost does not automatically minimize carbon emissions. Taken together, the four optimization problems and the unifying case study show that delivery robots, cargo bicycles, and parcel lockers are complementary rather than competing technologies, each suited to a different combination of customer density, infrastructure, and delivery requirement, and that coordination between replenishment and the final delivery leg, more than any single vehicle's own performance, determines whether a sustainable last-mile delivery system succeeds.