A female mathematician who develops algorithms for elevators

55-year-old American mathematician Teresa Christie (Theresa Christy) works for Otis Elevator Co. and is considered one of the best specialists in vertical transport. She devoted twenty five years of her life to the development and optimization of algorithms for elevators. She was attracted during the recent reconstruction of the Empire State Building worth $ 550 million. Teresa Christie increased the speed of elevators by 20% to 6 m / s, so they now pass the first 80 floors in just 48 seconds.

Teresa Christie took part in another high-profile project of recent years - the construction of the 451-meter skyscraper Petronas Towers in Malaysia, while the tallest building in the world. Again, her task was to optimally adjust the elevators, writes WSJ.

Each elevator has its own controller, which controls its work. In the elevator group there is also a group controller, from which the signal goes to the individual elevator controllers. This is where all optimization work is concentrated. Developers need to lay in the system algorithms of behavior: what elevator to go to the call, at what speed, how elevators should coordinate their work, where to be in standby mode. Modern elevators also weigh passengers - and take this information into account, although they do not display weight on the overall display.
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Here is a typical example. The passenger on the sixth floor pressed the call button to go down. Just at this moment one of the elevators is located on the seventh floor and goes down. But he already carries three people and twice stopped on the way. Is it right for him to stay the third time on the sixth floor? Although this will reduce the waiting time for the waiting passenger, but will increase the time for the other three.

In a building with six elevators and 10 passengers, there are 60 million possible combinations for moving them, this is a very resource-intensive task - and yet the conditions of the decision change every second when a new person somewhere presses a button.

Teresa Christie performs the main work in computer simulators, then testing the result in real experiments. “I have a feeling that I am being paid for playing computer games. I watch simulations, analyze what is happening, and try to improve my result, she says. - We are constantly looking for a magical balance. Sometimes what’s good for an individual is bad for others. ”

The task is not as simple as it seems, and for each building you have to enter unique settings for elevators. The main parameter is the waiting time, which should not exceed 20 seconds for each person. Teresa Christie explains that it’s in 20 seconds that people get nervous, because people hate waiting.

In the Otis Elevator Compass Elevator Intelligent Control System, each passenger before landing indicates the floor where he is going. After that, the system tells you which elevator to sit in and in how many seconds it will come. On the diagram, passengers are painted in different colors, depending on their destination.



Passengers of nearby floors are put in the same elevators to minimize travel time and number of stops. This is one of the inventions of Teresa Christie, in whose name 14 patents are issued, and a few more are pending.



Another of her inventions is support at the level of the reservation controller of an empty elevator after entering the password from the numeric keypad. For example, one hotel in Hawaii gives such codes to surfers so that they are not disturbed by the rest of the guests naked with boards. In this case, the cabin is guaranteed to come to you empty and will not stop anywhere along the road.

Its features are in each country. For example, in the city of Mecca (Saudi Arabia), it is necessary to ensure that the elevators will be able to quickly and completely clean the building from people five times a day, since most of them go to pray. Accordingly, in this city it is necessary to put more elevators in buildings than in others.

In Japan, the softest and silent elevators work. Whoever enters them for the first time, may first think that he is stuck until the doors open on the right floor.

It is necessary to take into account the number of passengers. In Asia, on average, more people enter the cabin than in Europe or New York, because people have less personal space.

Teresa Christie's career is not always progressing as planned. At one time, she received an MBA degree, but was never able to work as a manager: “I thought that I wanted to become a manager. But actually, I like to solve puzzles myself. I did not want to give them to anyone, I felt a little jealous, ”she admits.