Operational Reesearch and the urban cyclist

I am committed to cycling as a sensible means of transport, even though my own cycling has not been completely accident-free. The other day I was musing on whether there is much literature about O.R. and cycling. And then I heard about eBourbaki, which describes itself as "a mathematical problem-solving company" (no mention of O.R.!) and the competition that had been run to model cycle-hire facilities in London. Readers of "OR/MS Today" will have seen that one of the political conventions modeled the location of cycle-loan facilities in 2008. eBourbaki run their problems as competitions, and the winners created two mathematical models with one describing commuter flow and the other examining the possible configuration of any bicycle stations.

It is to be hoped that the city will work with the winners and consider using their solutions and models in the network design.

The models suggested that, for a London-based scheme to be successful, 12 large bicycle stations should be placed near railway stations in central London with 250 smaller stations distributed throughout the West End and the City of London. An average of 20 bikes per small station was found to be the most efficient number.

Visualising numbers

It is only distantly related to OR/MS, but I have touched on the problem of guesstimates before, as it is a sign of numeracy (an essential OR skill) to know when numbers "feel" right. So I was pleased to see the megapenny site which has pictures of what large numbers of one cent pieces will look like and weigh. In these days of governments bailing out banks and othe financial concerns, it is instuctive to note that $18 billion is just enough to fill the Empire State Building with one cent coins.

The Harvest Thanksgiving Supply Chain

In an earlier blog I mentioned links between O.R. and Christianity. September and October are the months when (in the Northern Hemisphere's temperate regions) churches celebrate harvest thanksgiving. (Cue for the traditional harvest hymn: "We plough the fields and scatter, The good seed on the land, But it is fed and watered, By God's Almighty hand." You can tell that I am a Brit, because I spell plough without a "w".) Increasingly church services also give thanks for the makers and producers of food -- and at our service yesterday the preacher thanked God for the drivers of delivery trucks -- she almost used the words "supply chain", but the congregation would not have been familiar with that technical term.

Operational Research and the Bible

An interesting diagram has been posted in a forum for vsiualising information.
The picture has one entry along the x-axis for each chapter in the Bible and there are coloured arcs between chapters which cross-reference to one another. (This means that there is a word, phrase or idea that occurs in one chapter that also appears in another; "The Lord is my Shepherd" in Psalms links with "I am the Good Shepherd" in the gospels.) There are 63779 such arcs -- the picture is beautiful. Mathematicians and O.R. scientists will recognise that the structure is a graph, with each chapter a vertex, and that leads to assorted questions about the graph. How many components does it have? Are there isolated vertices? What are the properties of the components?

I'd like to hear answers.

Operational Research and Psychology

Well, actually, as many people have pointed out in the past, psychology is part of O.R., so my title creates a false split.

A part of my education in O.R. was the apocryphal story about the O.R. consultants and the problem of the lifts in the skyscraper. Occupants of the building complained about the time they spent waiting for the lifts to get from the upper floors to the lobby. So the consultants looked at the options, they built models of the consequences of extra lifts, faster lifts, dedicated lifts from the upper floors, etc., etc. The reduction in mean waiting time was always very small. Then the psychologist in the team suggested that the company place mirrors in the waiting areas for each lift shaft. He explained why. Why? (see the end of this blog)

I had the same sort of problem at the weekend. Each year, on the second Saturday in September, I take part in a prayer walk around the churches of the city of Exeter, my home. The idea is that a group will start early in the morning, follow a winding route around the city, stopping to pray in about 25 different churches, praying for the city and its people. I have the responsibility of planning the route; for several years we have used the same route. This is not a TSP, of course, because the walkers don't end at the start point. It is not quite minimal but is quite close to the best.

In 2008, two new churches came into the list of city churches. We decided to include one of them, miss the other, and omit another, because it was linked strongly with these two. But the selected new church would add so much extra mileage to the old route that we needed a new plan. So we made the walk have two starts, with two groups starting at 8am and converging on the cathedral at 10am to walk for the rest of the day together. So I devised such a route; the two initial legs had minimal lengths for the churches that they visited, given the fixed end at 10am. However, I had forgotten the psychology. The second route had a lot of road walking, and went past the main railway station, so there was traffic. The consensus was that it would be better to walk a little further (about 300 to 400 metres) and walk beside the river on a footpath, away from the traffic. So that is what we will probably do next year -- alter the start and route to give more traffic-free paths.

Why the mirrors? The reason was that it was not the actual waiting time that people notices, but the perceived waste of time. Mirrors distracted people; some could admire themselves and tidy their clothes and appearance, others could watch. (In the 1970's there were sexist stereotypes for these activities, which I will not repeat.)

Education and brains

"To repeat what others have said, requires education; to challenge it, requires brains."

Mary Pettibone Poole, A Glass Eye at a Keyhole, 1938

I had not come across this thought-provoking quotation until yesterday; then I was in a meeting and found it inscribed on the wall of the small conference room. Yes, it has O.R. applications. Part of the skill in the O.R. scientist should be (must be?) the ability to recognise where a model developed earlier in a different context might apply to a practical problem. So queue theory is used for call centres and for slow moving inventories. Location theory applies to ATM outlets and airports. But sometimes the obvious is not appropriate -- then the O.R. scientist needs brains to challenge the obvious.

Wikipedia doesn't tell me anything about the author or the book. And I wonder who has used their brains and challenged Mary's words, rather than repeat them?

Operational Research and Christianity

I recently read that the educational background of the Bishop Sarah Frances Davis in the African Methodist Episcopal church has a degree in Management Science. Can O.R./M.S. help in such a role? In IAOR, there are several papers recorded which refer to applications of O.R. in the life of the church. In the 1970's and 80's, Malcolm King, Alan Mercer and I published some papers about the place of modelling in the deployment of clergy in the U.K.

[Malcolm King, David K. Smith and Alan Mercer "Towards Diocesan Planning" Journal of the Operational Research Society 29 p856-866 (1978); Malcolm King and David K. Smith "Are the Clergy Being Deployed Fairly?" The Churchman 5 p54-60 (1980); Malcolm King and David K. Smith "Planning the Deployment of Clergy" Long Range Planning 5 p104-111 (1982)]

Earlier, Alan had published "The Churching of Urban England" in the proceedings of the 1969 IFORS conference, which looked at the location of places of worship.

So there are two possible areas for fruitful O.R.; manpower planning, and location models.

I wonder if Bishop Davis knows about this work.