Ellis Johnson’s Accomplishments

The following bio for Ellis Johnson was written by Timothy L. Jacobs.

Ellis is one of the most influential research scientists in Operations Research and Mathematical Modeling.  This is especially true in the transportation industry.  His work in integer optimization, efficient column generation, assignment and routing algorithm development, fleet assignment, and crew and staff scheduling have impacted the air, rail and surface transportation industry worldwide.  Today, you cannot take a commercial without being the beneficiary of the ground breaking research either conducted directly by Ellis or one of his many mentees.  Ellis’ early work in crew scheduling, column generation and integer optimization led to the development of numerous crew pairing concepts and techniques central to efficient pilot scheduling and crew rostering in the airline industry.  Crew and fuel costs are by far the biggest cost airlines face for daily operations amounting to more than 46% of the total cost of operating a flight.  Ellis’ research helped bring efficiencies within the crew scheduling process saving hundreds of millions of dollars for carriers and in many cases making the difference between running a profitable operation or losing money.  Today, nearly all passenger and cargo carriers use crew planning systems that employ optimization algorithms that have strong ties back to the work Ellis initiated and championed at IBM Watson Research, American Airlines and Sabre.  This work has now been applied to numerous scheduling problems such as rail crew schedule, general staffing problems, and vehicle routing.

Ellis’ work also greatly influenced how transportation companies build and operate their schedules.  For transportation companies like airlines, the schedule is their product, so, if it is not constructed in a manner that efficiently meets customer demand, the company’s livelihood will be short-lived.  Ellis’s insights and mentorship helped lead to the development of models like origin-destination based fleet assignment to develop efficient schedules to better supply to passenger demand.  At the time of its development, this approach was able to increase a carrier’s profitability by half a margin point.  For American Airlines, that equaled about $172MM in increased profit annually.  Today, O&D fleeting is the norm and airlines worldwide use a number of commercial products that incorporate O&D passenger or cargo package flows into their network design, fleeting and operation.

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