Parking meter risk

In the street where I live, there are parking restrictions, so if you park on weekdays between 9:30am and 3:3opm, you must pay. The days and the times are to deter people from parking and catching a bus into Exeter, since the maximum length of stay is 4 hours. This means that there are three parking meters in the street. About once a week, a couple of men in a van come round to collect the cash from the machines.

Come to another city, Portsmouth, where my work has taken me, and there the parking meters in the streets that I use are labelled "No cash is left in this machine overnight". A similar notice applies in the "pay and display" car parks in the city centre of Exeter.

So we have different policies concerning the collection of cash. I doubt whether anyone constructed a model to determine the policy for our street and the different one for the second category. It could be an interesting model to work with. Balance the cost of collection, the amount expected to be collected, with the cost of a machine, the perceived risk of vandalism and robbery from a machine, etc.

Nappies, Diapers and decisions

From time to time, someone in the media raises the question "is it better to use disposable nappies (diapers) or cloth ones?" As Tina and I are childless, we have not had to face this problem in person. However, the debate about the answer is a classic case (as in Operational Research) of identifying the system in which you have defined the problem. The family is isolated from the problem of waste disposal, and concentrates on the costs and time needed for using either cloth or disposable. The waste disposal contractor (often local government in the UK) is concerned about the cost of landfill and is not bothered about the family. Society is concerned (ideally) with the total impact of a baby's lifetime in nappies. In the developed world, the option seen in Africa and Asia of letting the child run around without any nappy does not exist.

The speaker on local radio yesterday was a waste disposal person, and from his position, cloth nappies are best. But that is simply to look at the subsystem. According to several websites, and written reports, the choice is too close to call. Cotton growing, manufacture and then washing of soiled items, cause so much environmental impact that it matches the impact of disposable nappies in landfill. I haven't seen this in the O.R. literature.

Coincidentally, the book that I am currently reading (Hungry City: How Food Shapes Our Lives by Carolyn Steel) alludes to a problem which I have not seen in the reasoned discussion of the choice. How easy is it to dry a lot of nappies in a small modern British house or flat? Carolyn Steel raised the question of modern homes which are designed with minimal space in the kitchen, and British building regulations allow construction of houses with very limited floor area. So I wonder whether the answer to the question depends on how big your home is? There's a research area!

O.R. in Eritrea

When IAOR prints an abstract relating to O.R. in a developing country, it is usually cross-indexed with the name of that country. So the latest "OR in a DC" abstract marks a rare event -- it is the first that has been included (as far as my records go) about O.R. in Eritrea.

The paper is:
Cost analysis of an integrated disease surveillance and response system: case of Burkina Faso, Eritrea, and Mali
by
Zana C Somda, Martin I Meltzerl, Helen N Perryl, Nancy E Messonnier, Usman Abdulmumini, Goitom Mebrahtu, Massambou Sacko, Kandioura Toure, Salimnta Ouedraogo Ki, Tuoyo Okorosobo, Wondimagegnehu Alemu and Idrissa Sow
published in:
Cost Effectiveness and Resource Allocation 2009, 7:1doi:10.1186/1478-7547-7-1

Papers with so many authors/co-authors are also rare events.

By the way, if you don't know where Eritrea is, the map shows it in the north-east corner of Africa, bordering on the Red Sea.

Cost Benefit in New York

One of the few email newsletters that I really enjoy is the Internet Scout Report from the Computer Science Department, University of Wisconsin, even though it generally has little to do with O.R.. However, the phrase "weighing costs and benefits" leapt out at me this week, in relationship to the costs for tax-payers of a new sports stadium in New York, and the related benefits. The email gave links to news stories about the issue. Obviously this is an area for O.R. analysis (not just economics) and modelling. But perhaps the most telling comment is that in the Sabernomics blog, where it records:
There is little evidence of large increases in income or employment associated with the introduction of professional sports or the construction of new stadiums.