"Customer Mobility and Congestion in Supermarkets"

One of my papers just came out in final form. Here are the details.

Title: Customer Mobility and Congestion in Supermarkets

Authors: Fabian Ying, Alisdair O. G. Wallis, Mariano Beguerisse-Díaz, Mason A. Porter, & Samuel D. Howison

Abstract: The analysis and characterization of human mobility using population-level mobility models is important for numerous applications, ranging from the estimation of commuter flows in cities to modeling trade flows between countries. However, almost all of these applications have focused on large spatial scales, which typically range between intracity scales and intercountry scales. In this paper, we investigate population-level human mobility models on a much smaller spatial scale by using them to estimate customer mobility flow between supermarket zones. We use anonymized, ordered customer-basket data to infer empirical mobility flow in supermarkets, and we apply variants of the gravity and intervening-opportunities models to fit this mobility flow and estimate the flow on unseen data. We find that a doubly-constrained gravity model and an extended radiation model (which is a type of intervening-opportunities model) can successfully estimate 65%–70% of the flow inside supermarkets. Using a gravity model as a case study, we then investigate how to reduce congestion in supermarkets using mobility models. We model each supermarket zone as a queue, and we use a gravity model to identify store layouts with low congestion, which we measure either by the maximum number of visits to a zone or by the total mean queue size. We then use a simulated-annealing algorithm to find store layouts with lower congestion than a supermarket’s original layout. In these optimized store layouts, we find that popular zones are often in the perimeter of a store. Our research gives insight both into how customers move in supermarkets and into how retailers can arrange stores to reduce congestion. It also provides a case study of human mobility on small spatial scales.

A New Way to Give People the Raspberry

Hopefully, nobody who goes to the market and notices the liquid-droplet remnants from the minor raspberry avalanche will think that those are drops of blood.

Only one person would dare give them the raspberry...

Chocolate-Covered Bacon

I was just at Whole Foods market, and I was completely broken by looking at Mo's Bacon Bar, which is chocolate-covered bacon. Whole Foods had both a milk chocolate and a dark chocolate variety (though the dark chocolate was only something like 62%, which is pretty weak). I didn't buy it, though. I like chocolate, and I like bacon. But... WTF?

(I did buy almond butter, however. Mmmmm....)

Brief Notes

George Carlin has a section in his routines called "Things that piss me off!" and Bill Maher has a section called "New Rules" of a similar vein at the end of each episode of his current show.

Well, here's a new rule: When the checkout line in the market is an express lane that requires you to have "15 items or less", then you should have no more than 15 items. In particular, this means that having more than 30 items is right out! Similarly, the people who work at the market should enforce this! If you want to not have such a line, that's perfectly fine. But if you're going to have this kind of line, there's no bloody point unless you actually enforce the damned requirement. (It's worth mentioning as well that it is a regular occurrence to see somebody with too many items in these lines.)

In terms of bureaucracy, I am still waiting to get my contacts that were supposed to arrive at my apartment a week before Wednesday. Apparently, they were mailed out on Tuesday, which is the last day I called about them. The doctor's office has a shipping number, so if they don't arrive today, I am to call them and ask them to call the post office with the tracking number to see what's up. There were previous things associated with buying my contacts through them now that my doctor is part of an office with another person. The way I used to order contacts is that I would make one phone call and the contacts and bill would both arrive on the same day. In this case, I am at 5 phone calls and counting (and my credit card was charged over 2 weeks ago and about 3 calls ago).

On a similar note, I didn't have my Blue Cross information with me when I got some shots a little while ago, so I paid directly and then filed a claim with Blue Cross (that I have through Caltech) to get the appropriate subset of that reimbursed. I followed the instructions (and provided exactly the information shown in the sample filled-out form that was included!) only to find out that the sample they include is utter tripe and that there is more information I should get from the doctor. After a couple of rounds of that before I found out what they really wanted, I got the information from the doctor and filed the claim again. On Saturday, I got an incomprehensible statement that didn't indicate that I had overpaid what I was required to pay. I called them today to find out that they had sent the money to the doctor directly and that the doctor is supposed to, in turn, send me a check to reimburse the overpayment. I then called the doctor's office and the person I talked to said she didn't think it worked that way, so she would talk to her boss (the doctor) and then get back to me. I hate insurance companies. Remind me never to forget to bring my insurance information with me when I go to a doctor's office (and, I guess, to have it with me as a standard deal in case there's an emergency). The number of hoops one has to go through is just ridiculous. And I still am not actually done. Sigh...

Enough ranting for the day. I may have more later. Let's hope the moving company stuff goes smoothly. Can you tell that I'm optimistic?