Decision Models:Compendium of Web Site Reviews

A Tutorial on Integer
This simple Web site offers an interesting tutorial introduction to linear programming and modeling with integer values (e.g., people assigned to jobs, etc). A variety of different types of problems are discussed, but since I have a particular interest in the traveling salesman problem (here called the "traveling salesperson problem" in a nod to political correctness). Unfortunately, I found this discussion and explanation more confusing than that in our book, which was quite cogent. I also had to wonder how up-to-date the Web site was when I bumped into the line "The second example occurred just last week (October 1995)..."

The one area where I thought the site did offer some good material was on the cutting plane technique approach to solving network problems. My instinct is that this technique cannot solve problems of more than minimal complexity, but this information - and the information in our book - suggests that I'm wrong, and that in fact it is a valid solution. It might be hard to program, however.

Compendium of NP Optimization Problems
This site, hosted by Professor Viggo Kann of the Royal Institute of Technology in Stockholm, offers a wide range of optimization problems. Most of them seemed too advanced for our OPRE class, but they certainly sounded most interesting, including "sequencing on one processor", "shop scheduling", and just about everything in "games and puzzles". In particular, the "Minimum Travel Robot Localization" seems like it'd be quite an interesting application of the traveling salesman problem (at least, that's the classic combinatoric problem I'd compare it to).
Decision Theory and Decision Trees
This terrific Web site is part of the MindTools site, offering a range of career-related analysis tools and references. The site also includes a smartly designed online bookstore. One of my favorite areas was "Techniques for Controlling Stress", but perhaps that's just because this is graduate school! Anyway, this particular area of the site has a cogent discussion about decision tree analysis: choosing between options by projecting likely outcomes. What I thought was so valuable is that they present a complex topic in a simple and straightforward manner. Of course, computer scientists are familiar with decision trees because they're flowcharts gussied up with some probabilities tossed into the mix!
Expert Choice
This is a company that does operations research professionally, though they refer to a specific flavor of OR "analytic hierarchy process". The roster of employees is quite impressive, and the company states that "today, Expert is used to allocate over $30 billion a year for Government and commercial agencies worldwide." An impressive testimony to the value of OR and scientific decision making!
Created by a merger of the Operations Research Society of America and The Institute of Management Sciences, the Institute for Operations Research and the Management Sciences offer a reasonably designed, highly informative Web site geared towards both the practitioner/member and OR students. I thought that the Student Union area was particularly interesting, and addressed many of the shortcomings of the BLS site discussed earlier. In particular, the many educational programs sounded quite interesting. Were I to choose a career path focused on OR, this site (and organization!) would clearly be an invaluable professional resource.
Operational Research Society
This web site for the Operational Research Society offers the most attractive visual design of all four sites reviewed this week, but had considerably less information - particularly for students - than the great INFORMS site. However, the study groups seemed most interesting, and if OR was a strong focus of my MBA studies, I would be quite likely to sign up for one. The book "Selected Readings in Operational Research for Developing Countries", offered in their online bookstore, sounded most interesting too. Nonetheless, this site offered little incentive for me to bookmark it for a future visit while in this course.
Operations Research Analysts
This site, managed by the U.S. Department of Labor, Bureau of Labor Statistics, offered an interesting description of the prospects and tasks assigned to an operations research analyst. The information was presented in an attractive format, and the "search by occupation" invited visitors to explore and learn more about different occupations tracked by the Department. It was difficult to quantify "good job prospects", however; did that imply that 99/100 would find a good job, or 40/100? It was also interesting that they highlighted the problem that few jobs are titled "operations research analyst", yet didn't suggest common alternative titles for job seekers. I also found it interesting that the federal government was the second largest employer of OR analysts.
Operations Research/Management Science Today
The Web site from Lion Heart Publications for Operations Research/Management Science Today was very interesting reading, and the cover of the latest issue, with its "The Worst Day Ever" definitely piqued my interest! What's nice also is that the magazine issue itself shows up online a few weeks after the print publication is distributed to INFORMS members (from what I can glean on the site). Given my professional experience, I was particularly gratified to read the article "Web Services: OR's Newest Ally?"
This site, hosted at Imperial College Management School in London, England (my birthplace!) and run by J. Beasley, offer some great information about operations research and linear programming. With lots of examples, I particularly liked the lecture notes about Just-in-Time manufacturing LP applications. I've always been interested in JiT, partially because it's a very logical way to structure a manufacturing facility, and partially because it seems remarkably hard to pull off without overstocks or shipping delays. It's interesting to read how OR fits into this picture. I really enjoyed reading Prof. Beasley's historical overview of JIT and Japanese labor relations, too. A valuable insight into the evolution of JIT as a (rather unique) approach to manufacturing.

What most surprised me was that I began to realize that operations research and linear programming are sufficiently intertwined that you really cannot have one without the other. Coming into our OPRE class, I thought that QSB would be an 'adjunct for some experimentation', and am learning - through readings on sites like this - that it's really quite more of an essential tool for any meaningful operations research.

The Decision Analysis Society
Though I first thought it was a joke, this Web site from the Duke Fuqua school of business is for a group of OR people working on the evolution of decision analysis and OR itself. I do have to point out that while they have a link "How to Join Us" they don't have a link "An Analysis of Why To Join Our Society", which seems like a natural!
The Open Directory Project: Science:Math:Operations Research
A part of the wonderful, completely volunteer-managed open directory project, this area offers a wealth of online resources for the operations researcher and student of OR.
Virtual Duality
Traveling to the other side of the planet, this site features information about dynamic, integer and linear programming, including a personally helpful tutorial on the basics of linear algebra. Hosted by IFORS (The International Federation of Operations Research Societies) at the University of Melbourne in Australia, the site offers lots of examples of different OR topics, organized into simple modules. One criticism I have of this site, however, is that everything is labeled by its OR jargon name, so if I didn't know what "Dijkstra's Algorithm" was, a module with that name would be less helpful. Similarly with "Royal Optimization" and "G/G/s Queues". Perhaps an introduction to all the material on the site would help overcome this limitation.

Since we were assigned to look at "Virtual Duality", I popped into that area of the Linear Programming area, and found an online system that computes the dual of a given LP scenario. Obviously helpful for one of the homework assignments this week! Again, however, the jargon that pervades this site was present even in the description of the virtual duality system: "the dual problems associated with given (numerical) instances of the primal." What Primal?