Category: Blogs and Web

The Blue Ball Production Problem

It’s course preparation time again. For those of you teaching production or scheduling, if you are looking for a graphic to show the need for split-second planning in certain production processes, I highly recommend the Blue Ball Machine. Hypnotic!

From Wired Magazine:

A Rube Goldberg machine made of animated tiles, with hundreds of blue balls moving in time to music from Pee-wee’s Big Adventure.
Max [of http://www.ytmnd.com]says: This is our most viewed title ever. It was created by the Web site Something Awful – they had 100 people make 1-inch tiles, and the only rule was that a ball had to enter at a certain place and exit at another. It came out awesome.

Bird flu Logistics

J. Michael SteeleJ. Michael Steele has a blog on “Bird Flu Economics”, looking at economic aspects of an avian inluenza pandemic. His blog provides a welcome dose of reality in the arguments about effect and appropriate response to the avian flu. A recent post of his points out how little logistics (read OR) planning has been done in this area.

Logistical nightmares are at the heart of every H5N1 pandemic senario anyone has ever concocted, yet it is hard to tell if anyone in the OR community is currently looking hard at this.

Isn’t it clear that pandemic logistics is a research area that deserves encouragement at every level?

Let’s at least catalog what is being done — or not being done!

Steele has done lots of interesting work. In the early 1980s, he did a lot of fundamental work in the use of probabilistic analysis in combinatorial optimization, including writing a great chapter in the Traveling Salesman book (as an aside: it is a travesty that the book costs more than $250; while dated on the TSP, it still provides a great overview of the various themes associated with combinatorial optimization and remain one of my favorite books of all time). His current work is primarily in mathematical finance and statistical modeling. He has a recent book on the Cauchy-Schwarz inequality (a much more reasonable $30!).

Looking for Another Editor!

I am on the search committee to find Matt Saltzman’s successor as Editor-in-Chief of INFORMS Online. I was the first such editor, then Matt took over for the last six years. It was great being the first editor (1995-2000): there was so much to do that anything we did was better than what we had. Matt has worked hard to bring IOL up to a higher professional level, so now the webpage doesn’t look like something an amateur put together in an afternoon (which is what I did!). Behind the scenes, Matt and his team put IOL on a much stronger technical base.

Now, after 11 years, even the role of IOL Editor is undergoing change. Why have an OR professional be the Editor of IOL? After all, the Editor of OR/MS Today is not an OR professional: he is a journalist. Should IOL be any different?

I think having an OR person as editor of IOL is still very valuable. The goal of IOL is to create community, and outsiders would have a hard time figuring out what community would be valuable to an OR/MS person. What we need is a technologically savvy person with a broad interest in OR and advancing the field.

This position is absolutely key to INFORMS and to our field in general. I hope there are many applications, and many thoughtful discussions of the role of Editor of IOL.

The full Call for Nominations is here:

Continue reading “Looking for Another Editor!”

Poker and Airline Scheduling

There is a nice post on the Math and Poker blog on the importance of identifying key variables and the flexibility that is available for many decisions in a process. The example begins with a standard critical-path type scheduling example, making the point that jobs not on the critical path have some flexibility. This point is extremely well known, of course, but it is interesting to think about what to do with this flexibilty. In poker, the author of the blog (I can’t see who it is), notes that there are a lot of situations where the difference between the best and next best decision is not a lot, but can be used to set up the opponents in particular ways (EV in the following is Expected Value):

The way that most people think about EV in poker is like treating each of these tasks independently. If I bet this hand what happens? Things like folding when the pot is small even if calling is +EV for this hand are ignored even though doing so might set up other players, or that player, to make a big bluff on some other hand.

If you really want to optimize your stratagy and maximize your win, they you just have to look at the game in a global sense. A strategic Expected Value of a collection of actions is what you need to consider, not a tactical Expected Value of one action.

So what does this have to do with airline scheduling? A lot of work is being done right now to combat the fragility of airline schedules. David Ryan of the University of Auckland gave a talk last week at the EURO conference on his work with New Zealand Air (my plans are to visit David for most of next year, so I was particularly interested in his work). In this work, David had a measure of fragility of a schedule (generally due to crews changing planes with a short layover: one late plane could quickly affect many others). David showed that there were near-optimal solutions (based on the main objective of minimizing cost) that had much better properties with regards to fragility. Things got even better if the schedule could be modified slightly.
The problem with both the poker example and crew scheduling is that the objective is much “fuzzier” than the underlying main objective. And that makes it much harder to “optimize”.

Resource Pointers

I was vexed to see that there was a bug in the software at the INFORMS Resources Page that sprung up in the transition to a new machine at INFORMS Online.  For the past two months, no submission to the system was being logged.  The worst part is that no one seemed to notice!

This system used to be “Michael Trick’s Operations Research Page”, and was, I think, a key resource on the web in OR/MS.  Now, with the advent of google, it is unclear what role these resource collections have.  If you know roughly what you are looking for, simply googling terms seems the right way to find things.  If you don’t, however, these resource collections can be useful.  But they are incredibly painful to keep up to date (about 15% of the pointers at the site are not valid, but keeping on top of them takes a lot of time).  Two-thirds of the submissions are not OR/MS related, so the editing process is pretty tedious.  So is the effort worth the usefulness, or is this just another aspect of the web that had its time?

Operations Research and Lego

Lego symbolThe blog Deviant Abstraction points out that Lego’s (you know: building blocks that can be put into lots of different shapes) new Lego Factory has an interesting OR problem to solve: how can they put together packets of pieces so as to minimize waste when customers can order from more than 500,000 different pieces? Of course, OR needs to be used here. If anyone has a technical reference, I would love to see it! As someone who has a little more Lego than any mid-40s guy should have (and my two year old is not allowed to touch it! He can get his own!), the combining of two of my passions is appealing.

Wikipedia and Operations Research

Wikipedia is in the news, due to some inaccurate/obnoxious/insulting entries regarding a journalist and alleged involvement in the Kennedy assassinations.

Wikipedia is an interesting effort to harness the knowledge and energy of hundreds of thousands of people to form a new type of encyclopedia. The key aspect is the ability to freely enter information (or misinformation) and edit what is there.

The entry for operations research is pretty good, covering both the general (what is OR) and the specific (some military and other examples). The pointers are well selected. The “history” gives all the past edits, and it is striking how many edits went into this entry alone. That is one advantage of multiple people working on it: 100 edits don’t seem bad if 50 people are doing them.

But what is to stop someone from putting “Operations Research is an upsidedown cake with cherries” into the entry? As this Wired article describes, with enough interested volunteers, such vandalism can get corrected within minutes. Of course, that assumes the entry is in an area with knowledgeable and active volunteers. I wonder how much misinformation is stored in the backwaters of wiki.

Despite the doubts, I think a wiki based Encyclopedia of OR would be a tremendous asset for the field. While some expert-based encyclopedias are fine (Gass and Harris have a good one, at an astounding $620 new), a community based wiki would be more up-to-date and be able to cover far more.

Web Resources, then and now

Wandering around the web, I came across a site that had copied my web page on pointers in Operations Research from 1994, presumably to avoid the then-slow cross-Atlantic downloads. It is stunning to remember what life was like pre-web. That page has about 50 pointers, about half of which were “ftp” or “gopher” (a http/html precursor). And I think that page was pretty complete! Compare that to the current INFORMS Resources page which has about 1500 pointers (100-200 of which are broken, but I’m getting to those) and is by no means complete.

I’ve been thinking about the value of these resource collections in the age of google. I spend a fair amount of time with the Resources page, but even I, when looking for something in OR, start at google. I think Resource pages are useful to get a handle on an area, and I am glad we have one for OR, but it certainly isn’t the critical page it was pre-google.

Blogging

It’s been about a week that I have been keeping this blog, and so far I think it has gone well. It is nice to see the activity (I have opened up my sitemeter so you can check out the stats as well): there’s about 20 visitors a day, and people are clicking around to explore, so many are staying for some time. Not many comments, though: I must attract shy visitors! Comments, of course, are welcome: feel free to comment on an individual post or on the blog in general. Easy enough to do: just click on the number of comments associated with an entry, and you get a chance to both read the comments and to add one of your own.