Friday, July 31, 2009

Teaching Facility Location: Lessons Observed

This summer I taught Facility Location to a mix of seniors and graduate (mostly professional masters) students. As usual, lessons observed.

The course is billed as Logistics and Supply Chain Management. In particular, it is a course number that has not been used for a while. The department has pledged to have a couple courses offered every summer, so this was one of them. Of the other courses in the department, there is one course titled supply chain management, but it focuses on production. So, in consultation with that professor, this course was focused on Outside-the-plant rather then inside-the-plant.

The original intention was to make this a combination of facility location problems and vehicle routing. The texts for the course were Facility Location: Applications and Theory (eds Drezner and Hamacher) and Logic of Logistics (Simchi-Levi, Chen and Bramel).

The plan for the course was for me to teach the first half of the course covering the basic models. After that, my sense is the goal is for the students to see as many models as possible, but it probably did not matter which ones. So I had the graduate students teach a module of their choosing while the undergraduates would present an application paper found in an academic journal (usually Interfaces).


1. Software and programming: For the course, I informed enrolled students about a month before the course that we would use programming (C was expected, but any language of the student's choosing was allowed). Early on there was an assignment that required implementation of an algorithm, this was very difficult. What this really means is we need to expose students to programming more often so they get used to the idea they have to implement what they are learning, not just learn equations. For linear programming, we used GLPK. The original plan was to try to use Pennsylvania based data and the student versions of the LP solvers could not handle that. And is it turns out, noone remembered how to use LINDO/LINGO anyway. But because they are not used to programming, this was hard too. Most of them got GLPK to work, and I suspect that it is easier to figure out then LINGO was.

2. In class exercises: The first day of class I reviewed linear programming, then made them do a formulation in class to see what you remembered. And, it was useful to know just where the students were. It was a good thing I did this. I did have to scale down the course, and I changed topics.

3. Class interests: The other thing I did was ask the students for their interests. Based on this I (i) switched out one of the major topics and (ii) for grad students that did not have a preferred topic, oriented them towards topics that people were interested in.

4. Textbooks: The Facility Location book was good, but there were no exercises and a few editing errors. Most of the grad students who presented topics covered here found it dense, and did not catch critical aspects of their topics (generally, we figured this out when they scheduled time with me to review the topic and I explained the essentials) The Logic of Logistics book is probably too technical for undergrads and professional masters, as students with these backgrounds are not used to doing proofs. I ended up using Nahmias Operations Management to cover inventory and forecasting.

5. Forecasting: If I'm covering inventory, I need to cover forecasting. This was covered as part of one of the graduate student presentations, but I probably needed to do this topic and the graduate presentation can build on it.

6. Graduate presentations: Of the 9 presentations, I'd say 2 were very good, 4 were adequate (although 2 of these were on more difficult topics, so these would probably be considered good), 1 was marginal, 2 were strikes. One of the effects was a substantial increase in variance in the homework and test questions related to the graduate presentations as opposed to mine. Part of the presentation grade was the performance of the class on the related homework problem, which did correlate with my impressions. A few of the graduate students mentioned that they have been able to apply the topic of their talk almost immediately at work, which is rather gratifying. So overall, I think the idea is sound for this topic. But I need to find time to review the topics afterwards for quality control to ensure that the topic is learned.

7. Homework: This class was compressed during the summer, so I did not get as many homework problems as probably were needed. Most topics were only covered by one assignment and one exam problem. Even at this, they seemed to take a very long time on homework. In a normal length term, I would get out twice as many questions. In addition, I think we could get their computer skills up in the first couple weeks so that their performance on the homework would improve and become more efficient.

8. Undergrad presentations: The undergraduates reviewed one application article in the literature and write a short paper and presentation. First issue is for most of them, the first article submitted for approval (I wanted to approve the articles they selected), most were not applications. As one stated "I did not understand the article, I just saw symbols I recognized" This probably means I needed to discuss the difference between application and theory better, and how to read an article. (Yes, I had pointed them to Interfaces, but somehow people found the Journal of the Operations Research Society and thought that would be a good source.) For the papers and presentations, the students were much better presenters then writers. We've apparently done a good job creating powerpoint rangers, who cannot read or write (I've called them out on their inability to read on several occasions, and letting students know on their homework that I'm pretty sure they would have done better if they read the problem more carefully. I bullet point the relevant details in the assignment.) In addition, everyone went way over the desired length (~5 pages) At the beginning of the course, all of them were concerned with how long it was and I was assuring them that there was more then enough material for them to get 5 pages of material. I should have impressed on them that the real problem was getting the paper short and concise.

Homework and exam problems: The problems I gave were a mix of computational problems and formulation problems. During a teaching workshop, one comment a more experienced teacher made that the standard for teaching and evaluation was that he determined what questions someone in the class got correct, and that was his potential score. His goal was to keep the potential score in the 90s. For me, it was 100. And I'm pretty sure that they learned the material from me, so I feel pretty good about that. But I need to find ways of shortening the feedback loop, and have more points of comprehension checking, because I suspect that could have helped some.

I am teaching in the fall the undergraduates the prerequisite course to this. The department is going to a direction where there is a lead professor on the main undergrad courses, so we've talked some on how to teach it. The focus is going to be pushing formulations more then the actual algorithm (which none of them will ever implement it because we always use solvers). Also, we're going to try to teach a modeling language as well as Excel (and in place of LINDO/LINGO, which are essentially matrix generators) The theory being that the modeling language has a nearly direct correspondence with the math formulation, so that they will reinforce each other for later.

My other plan is to ask the students to write a paper on a journal article, which was something that I did when I took this course as an undergrad. And my thought is to have them do two papers on the same article. First the 5 page paper (with a strict limit on the five pages). Then, after they get feedback, the two page summary paper, to force them to be concise.

Thursday, July 30, 2009

Movie Review: Harry Potter and the Half-Blood Prince

I saw this Saturday with some friends. The previous movie sees the return of the death eaters and Voldermort in the open.

The story revolves on Harry viewing his role as "The Chosen One" as his own. Of course, with all the plot lines, this is hard to catch. And, he has that teenaged I-am-special-if-only-everyone-else-could-figure-this-out world view. At least he does in the book. The movie has Dumbledore understanding perfectly how wonderful Harry Potter is, although he is apologetic about demanding so much of him. In the book this is also true, but I don't remember Harry being quite so understanding of things.

The films still suffer from too many plots going on at once. This sort of thing works out better in books, in films it gets confusing since some characters are doing double and triple duty.

I remember not liking the book so much, because the Harry Potter teen-age angst was in full form at this point, with very little redeeming virtues. But with this watered down for the movie, it is harder to figure out his motivations. Or motivations for many of the other characters (ok, all the girls in potions class are pretty easy to figure out, but lots of other people seem pretty random if you had not read the books.)

Oh, the major character development plot seems to be all the kids starting dating, and it has to be with major drama. Again, this part did seem to work out better in the movie then the books, but it still seems compressed.

Thursday, July 23, 2009

Restaurant Review: Tamari, Lawrenceville

3519 Butler St.
Pittsburgh, PA 15201

We arrived around 6:30 and they were busy. We hung out at the bar and had a fun conversation with the bar staff as well as the owner's father (of China Palace) At first, they tried to seat our group outside, and we were eventually seated, but we eventually were chased in by the rain. So we ended up at the sushi bar, where we had front row seats of the chef at the stove. So we had a treat watching a hopping kitchen as the orders came through with head chef Roger Li keeping an eye on things from the side (it was a narrow kitchen).

I had the 16 spice rubbed in pork tenderloin and I was able to taste wrapped shrimp (pictured). The confidence of the kitchen showed when their medium rare was done like it should have been (i.e. not overcooked). The purpose of this restaurant is not feeding volume, in fact the portions are nicely sized. The focus is providing good food. Seasoned uniquely and intended to be savored. And I did so, one bite at a time.

Following lessons learned from his father, owner Allen Chen was wondering the floor chatting with customers. At our front row seat we watched Roger Li manage his kitchen, mentoring younger staff and even exchanging a few words with us watching. A wonderful eating experience, and something creating that makes eating in Pittsburgh fun.

Recommend this review

Saturday, July 18, 2009

Book Review: A Rumor of War by Philip Caputo

A Rumor of War A Rumor of War by Philip Caputo

My rating: 4 of 5 stars
This was a book club selection. And not by me :-)

Philip Caputo was a marine lieutenant among the first units in Vietnam in 1965. And his unit, like all such who are the first of their generation to go to war, was unsure of what they would find, looking to their few veterans from Korea to what it would be like, and the guidance from above. And the guidance from above was that it would be easy.

It was not. And Caputo shows what it was like at the ground, the walking into the unknown, not knowing what was ahead. A war where they did not know who was the enemy, and in every village, they did not know how to tell who was who. Their good intentions on dealing with the local population, spoiled by the fact that their opposition was embedded with that same local population and using that as their striking ground for their attacks on Caputo and his marines.

It is this description of dealing with the uncertainty of war that makes this stand out. And to make the example more stark, the second part of the book takes Caputo on his next assignment, staff officer in Vietnam. Far from the unknown of the battlefield, he is now in a war that is measured in numbers on a board, where the planners of war create their plans in willful ignorance of conditions on the ground, asking for certainty that does not exist. And you realize what others like Halberstrom and McMaster have stated in their books on the same era, that this pattern of making decisions in ignorance was even higher as you got further away from the battlefield.

Caputo also shows what a difference it makes to have a commander who desires to get beyond this. He describes a change of command, where the new commander insists on recognizing the reality of war, almost in opposition to the staff that he inherited. And the two commanders contrast with Rick Atkinson's description in "In the Company of Soldiers" of the general of the 101st Airborne during the 2003 invasion of Iraq , whose recognition of facts on the ground which higher levels were denying changed the way the 101st went into battle.

This was a good war book, not one that focused on glory or horrors, but what it meant for men on a battlefield to deal with all the unknowns of war. Very apart from those who speak with assurance based on ideology instead of experience.

View all my reviews >>

Monday, July 13, 2009

Book Review: Beginning Databases with PostgreSQL: From Novice to Professional by Neil Matthew

Originally at Goodreads

Beginning Databases with PostgreSQL: From Novice to Professional, Second Edition (Beginning from Novice to Professional) Beginning Databases with PostgreSQL: From Novice to Professional, Second Edition by Neil Matthew

My review

rating: 5 of 5 stars
This has proven to be a very good book. I'm not a database expert, but I happen to need PostgreSQL because I am working on a project that involves GIS, and PostGIS turns out to be a very appropriate tool for what I am doing. This book got me started and has helped me through the importing of data, understanding basic functions, and incorporating PostgreSQL into my programs (I use a combination of R, Python/Jython and Java. The book does not talk about them all, but what is in there carries over pretty well.) I've also used this to use BIRT and to link my PostgreSQL databases. Again, it is not spelled out, but what was in here brought me well along the way to making it work.

View all my reviews.

Sunday, July 12, 2009

Book Review: Applied Spatial Data Analysis with R by Bivand, Pebsma, and Gomez-Rubio

Originally posted to Goodreads. Applied Spatial Data Analysis with R (Use R) Applied Spatial Data Analysis with R by Roger S. Bivand

My review

rating: 5 of 5 stars
Applied Spatial Data Analysis with R (ASDAR) is written by the same people who wrote and maintain the spatial sp class in R. The book is not a statistician's text on mathematical geo-statistics, rather is focuses on taking geospatial (e.g. GIS) data and applying analysis within R. Not being a statistician, I used the book to learn how to manipulate geospatial data for my own analytical purposes. The mark of a good technical book, not only did I learn about how to work with the standard geospatial data types, I was able to implement analyses using the material in the book.

The book has three parts. First is an introduction to spatial data. Much of it is orienting the reader to the vocabulary of geospatial data such as point, line, polygon, grid, coordinate system, projection. It also motivates why using R for spatial analysis. (The other options would be within a GIS such as GRASS or ARCInfo, custom functions using C++ or Java, or Python, which has been incorporated into many GIS environments). In particular, it looks at the many packages and analysis built up that uses the sp package and data structure, allowing many developed analytical methods to be used together to build a complex analysis. (this is similar to my purpose, taking advantage of the fact that R provides a standard entry point to several computational toolkits that I use.)

The second part discusses accessing and using geospatial data in R, which fulfilled my purpose. It is detailed documentation on the various spatial classes and the methods that are applicable. There are descriptions and examples of how to visually display geospatial data. The chapter on data import and export covers GDAL/OGR, coordinate reference systems, projections and transformations, and what you would need to work with formats such as shapefiles, PostGIS, KML, image files such as tiff files and Google Earth overlays (PNG), or directly with GRASS, TerraLib, or Python interfaces with ArcGIS, RPyGeo.

The last part is on implementing geostatistical methods such as for pattern analysis, geostatistics, areal analysis (geographic aggregation), or epidemiology. I cannot comment too much on this as this is not an area that I have expertise, but the methods look both adequate as well as practical to use.

While the intended audience of this book are statisticians working with geospatial data, I would also recommend this to those who do data analysis or modeling with geospatial data. Most of the analytical texts I've seen discuss algorithms. This text gets into the practicalities of working with real data formats and real data issues that are the inevitable first step in a project. And it does so at a more analytical level then the point and click interface instructions that are enabled by standard GIS systems alone.

View all my reviews.

Wednesday, July 08, 2009

PSO: Independence day at Hartwood Acres

[also posted to the Pittsburgh Symphony Website (give them a couple days)]

I went to school in the north suburbs of Chicago, and every year one of the highlights was the Ravinia music festival, where the Chicago Symphony and others would perform outdoor concerts on summer nights. My friends and I would pack a picnic dinner and picnic and enjoy ourselves, and then be treated to a wonderful concert under the darkening sky.

And a friend let me know about this July 4, when PSO was playing a summer night outdoor concert not too far away from home. So we went in anticipation of just a fun concert.

PSO plays at Harrison Hills Park

For an outdoor concert it was a bit of ambitious. Strauss, and Beethoven, with a cello concerto by Herbert for the first pieces in the program, with the rest of the program the more conventional Americana of Copland, Ives, and the Armed Forces Salute. Finishing with the almost obligatory 1812 Overture and Stars and Stripes Forever.

The Strauss, Herbert and Beethoven pieces were almost trying to hard. While nice pieces, they seemed to get swallowed up in the open air and grass and trees (and the ambient noise of the park).

Copland's Variations on a Shaker Melody from Appalachian Spring reminded me of Gabriela Montero's concert back in January, when she brought with her Air and Simple Gifts for its live debut after the presidential inauguration. This and the Ives Variation America provided a feel of Americana that you would want in a concert on that day.

The Armed Forces Salute as well as 1812 Overture and Stars and Stripes Forever are almost mandatory for a July 4 concert (it was getting dark by then, so I did not see our veterans stand in their turns).

But something was missing. Oh. "Musical fireworks" were advertised, but no actual fireworks??? It would have been a fun way to cap the night if this happened to be coordinated with some nearby town holding their fireworks to coincide with the last part of the show. *sigh*