Design 15: Queuing Theory

Theme

I didn’t know about Queuing Theory before researching my last puzzle "Computer Networks." I was reading a Wikipedia article about Network congestion and the term popped up.

I thought it was a really cool application of CS and math because the topic sounds niche, "waiting in lines," yet it applies to real world problems like restaurant service. I also recognized some of the same ideas appearing in areas I’ve worked with before, such as distributed messaging systems.

Grid

After completing the grid, I tried making changes to add more horizontal intersections for Preemptive because the middle portion felt sparse. I tried adding clues like Kendall and Jackson, but they didn’t fit the space and made the clue set too name heavy. Overall, I thought the grid still looked fine despite the slightly empty middle layer.

I do like how Balking, Priority, and Shortest form little vertical stairs on the left side of the grid. Birth-death, Markov, and Poisson do the same horizontally.

Clues

Birth-death felt a bit odd as an answer, but it’s foundational to Queuing Theory because it models the flow of customers between states. It’s also used in fields like epidemiology and statistical physics, so I wanted to include it.

Markov previously appeared as an answer in "Classical Natural Language Processing" and was referenced in a clue in "Algorithms in Context." I tried to make the clue more queue-centric, so I wrote: "Model where future queue states depend only on the current system state; foundational to M/M/1 queue analysis."

I thought the clues regarding customer behavior, Balking, Reneging, and Jockeying, were fun because they match my own behavior when encountering long lines. I didn’t know there were specific terms for these behaviors, but it makes sense since they reflect common customer psychology.

If I walk into a Trader Joe’s to buy a cheap snack and the lines are extremely long, I just leave (Balking). If I’m standing in line and the people in front of me have a ton of groceries, I switch lines (Jockeying).

If I’m waiting for the next available representative to figure out health insurance issues and the wait exceeds ~30 minutes, I hang up (Reneging).

Tradeoffs

I had never heard of Queuing Theory before stumbling upon it while scrolling through Wikipedia, so I don’t really expect many people to be familiar with it either.

I chose to make the puzzle simply because I thought it was an interesting CS topic worth sharing. Hopefully people can still learn something interesting about the field while solving the puzzle, even if they are unable to answer some of the clues.

In short, I traded familiarity for taste.

Notes

I think my next puzzle is going to be "Computer Security" and after that "Computer Architecture." It feels like a natural progression from "Computer Networks" and "Queuing Theory."