# Monthly Archives: September 2011

## crowd sizes, home energy usage, baseball odds, and pop songs

This is a blog post about four topics that have nothing in common.

This Popular Mechanics article on estimating crowd sizes is great. I wrote about crowd sizes earlier when I blogged about Obama’s inauguration, but the PM article goes into the details a little better.  Crowd estimates might be obtained by crowd-sourcing in the future. Why are crowd size estimates so important? “[R]emember that accurate crowd counting can have practical applications such as preparing emergency responders. If a fire, terrorist attack, stage collapse or other calamity happened at a large event, Westergard figures that within 20 minutes he could provide first responders with the location of the threat and rough estimates of the number of people who might need treatment.”

You simply must look at these numbers on the DOE’s average home energy use. This site generated quite a bit of discussion between my husband and I. On average, 31.2% of household energy is used for heating and air conditioning, 9.1% is used for the water heater, and 26.7% is used for kitchen appliances. The refrigerator alone uses 13.7% of a home’s energy. Compare this to a mere 2% of energy consumed by PCs and printers (and this was before everyone had more efficient LCD monitors). If you really want to help the environment, turn off the AC and get a smaller fridge. On second thought, maybe I’m not ready to be an environmentalist.

Nate Silver of the NYT calculates the odds that the Red Sox would not make the playoffs. On September 3, they held a 9 game lead over Tampa Bay, with a mere 0.004 chance of missing the playoffs. Ouch. As a Cubs fan, I found a little solace in the Red Sox collapse. It helps to reduce the pain associated with the many, many Cubs collapses over the years. (Luckily, I’m also a White Sox fan). The 10 teams who ruined the greatest chance of making the playoffs is surprisingly not dominated by the Cubs.

The image below is graphical proof that pop song lyrics are becoming more repetitive over time (I’m not sure if it answers the age old question: Music or Lyrics?) It shows that pop song lyrics contain fewer unique words than they used to. This blog post delves into the details. Songs have become longer over time, since technology no longer limits singles to be ~3 minutes long. It’s not surprising that (a) songs have more lyrics and (b) a small proportion of those extra lyrics are new (if the chorus is sung one or twice more, it would add no new words). Some excellent songs have few words (such as Hey Jude by the Beatles), so I wouldn’t equate fewer unique words to a song being bad. HT to John D. Cook.

Fraction of words in pop song lyrics that are unique. Is this graphical proof that songs are getting worse over time?

## only you (and your optimization model) can prevent forest fires

This month’s OR blog theme is the environment. I am going to write about forestry, a topic that was reviewed by Andres Weintraub and Carlos Romero in their Interfaces paper “Operations research models and the management of agricultural and forestry resources: A review and comparison.

The US Forest Service has been using linear programming models to plan long-range harvesting and tree rotations (FORPLAN, SPECTRUM, Timber RAM). A search on their web site yielded a few OR papers that go back to the 1960s. Forestry models can have sustainability constraints, where sustainability ensures that the harvest rate does not exceed the rate of natural regeneration and that the harvesting costs that do not exceed the rate of financial growth.  Mixed integer programs have been used to model a wide range of shorter-range problems, such as balancing harvesting with road building, how to perform weekly harvests, how to match the timber supply with demand, locating harvesting machinery, and truck routing.

These forestry models balance efficiency with ecological issues such as biodiversity, wildlife, preservation, soil protection, water quality and scenic beauty.  (I’ve never added a “scenic beauty” constraint to a model. It sounds like fun!) Forest managers have to deal with ever more stringent constraints, such as protecting more habitat/protected areas, planning for habitat patches with no grown trees using adjacency problems (areas that are cut cannot be next to one another, leading to checkerboard-like cutting patterns), and requiring corridors of forest to remain to allow wildlife species cover, feeding, and foraging opportunities.

OR forestry models have succeeded for many reasons, including these:

• They are suitable for the forestry problems at hand
• Forestry needs efficiency due to global competition
• Managers are familiar with OR tools
• Forestry firms are large enough to benefit from the economies of scale
• Users have been involved in building models and implementing the results
• Collaboration between OR professionals, academics, and forestry experts

Forestry problems have different features than agriculture problems. The forestry problems are often longer-term and the data are often harder to obtain than in agriculture problems. In agriculture, problems are often solved for a current season, where the costs, prices, and yields can be reasonably estimated from past experience. This doesn’t hold for forestry problems, where the sources of uncertainty often stem from future prices, tree growth rates, and disasters.

Some agriculture problems are variations to the classical Diet Problem that determines how to cheaply feed farm animals blends of various food stuffs. Of course, this makes sense. I am always surprised when I find out that an idealized OR model that I’ve used in the classroom really makes a difference (see Mike Trick’s post on using the Secretary Problem to find love).

I have written indirectly about OR and the environment before:

## Rich nerd, poor nerd: Show notes from an undergraduate seminar

Updated on 10/11/2011.

Today, I am giving a lecture to the honors students about how to manage their finances after they graduate. I posted my slides here if you’d like to see my presentation.

The podcast has been updated. You can listen to it below or you can go to the OR podcast page.

Show notes:

My justification for paying off student loans is from Megan McArdle at The Atlantic.

Wedding costs and why they are so biased are discussed by Carl Bialik at the WSJ.

Should you use a coupon on a date? I think that is a great opportunity to signal that you are financially savvy–it should attract other like-minded mates. A columnist on the Washington Post agrees. Their non-scientific poll suggests that I am not alone.

My parents could have written this Saturday Night Live skit called “Don’t buy stuff.” It’s not a bad financial philosophy.

Other blog posts on frugality:

## genre bending music

I recently tweeted about hearing bluegrass covers of Ozzy Osbourne’s songs in a coffee shop. They sounded great. Here is a short list of a few genre bending cover songs.

• Iron Horse performed the bluegrass versions of Ozzy Osbourne and Black Sabbath songs. They also have bluegrass tributes to Metallica (and a second to Metallica) and to the Goo Goo Dolls.
• There are a ton of bluegrass covers of rock songs out there. It seems to be a pretty foolproof formula. Dolly Parton’s cover of “Shine” by Collective Soul is great.
• A cello tribute to Metallica is rather interesting. It’s weird that there are so many Metallica tributes. What gives?
• Although not an album of covers, Metallica recorded an album with the San Francisco Symphony Orchestra. I like the version of “One” on this album.
• U2 is my favorite band. While, in general, their songs on the Joshua Tree are perfect and should not be remade, I love this electronica cover of “Where the Streets have no Name” by the Pet Shop Boys.
• Muzak versions of rock songs should be its own category. I started to feel old when my music started to become muzak. I once heard a muzak version of U2’s “One” that was the worst cover ever.
• Tori Amos’ alternative cover of Eminem’s “Bonnie & Clyde” is the creepiest cover I have ever heard. Tori Amos has done a lot of alt covers of songs that have been written and performed by men (she has a whole album of them!). Gender and genre bending covers are quite thought provoking, since they make me view the original song in a different light.  That, too, should be its own category.
• Some genre bending covers are without a doubt better than the original songs. I like CCR’s cover of “I put a spell on you” and No Doubt’s “It’s My Life.”

I could go on and on forever. I apologize for the complete diversion from operations research, but tweets from OR nerds on this subject required a response longer than 140 characters.

What are your favorite genre bending cover songs? Do you like or loathe your favorite music being remade in other genres?  How do you feel about muzak versions of your favorite songs?

## pictures of the carnage at the hands of Hurricane Irene

Three weeks ago, Hurricane Irene hit the North Carolina and Virginia coast. Although Hurricane Irene was quickly demoted to a tropical storm, the rain and wind caused massive power outages in the Richmond area. Most of the power outages and road closures were caused by trees that were uprooted during the storm (all of the power lines in the area are wbove ground, and it is very wooded in the area). Here are a few pictures that I took after the storm.

A tree falls on power lines outside of Richmond, VA. Carnage like this was *everywhere* Many tall trees are right next to the power lines, which makes the Richmond area vulnerable to power outages. More on that later.

Mature trees like this one were generally uprooted like this. It was incredibly sad to lose so many trees.

Another massive uprooted tree.

Most trees fell in wooded areas, in the streets, on houses, or on fences (like this one). Stacks of branches and logs line every street in the area.

There were 200 road closures in the county where I live immediately after the storm. Amazingly, 90% of these roads were reopened within hours of the storm by chainsaw-wielding police officers. Almost every road was lined with tree trunks.

This tree was uprooted and was propped against a building. It stayed this way for weeks. This was not exactly safe. However, the fact that trees were left propped against buildings where they could easily fall on pedestrians highlights how limited the recovery resources really were.

I love this picture. A power line goes through a group of trees. Public services are really good about trimming trees near power lines to avoid branches downing a power line during a storm. You can see a a that the power line goes through a hole where the trees were trimmed around the power line. This keeps our power on during normal storms but not when we get real wind gusts. This in part explains why we had so many power outages here in Richmond when we are so far from the coast.

## am I the only person who doesn’t feel betrayed by Netflix?

I have been a huge Netflix fan ever since I became a customer 5 years ago. About 1.5 years ago, I figured out how to use my DVD player’s streaming options and have been enjoying free Netflix streaming ever since. This is why I’m not upset with Netflix:

• Netflix’s streaming service was in beta testing for awhile, and therefore, it was free. I was under the impression that it wouldn’t be free forever.
• Of course, I don’t like to pay \$8 per month for streaming, but it’s not unreasonable to pay for a service that I receive. People often revolt when they are asked to pay for something that they previously received for free.  Maybe my inner anarchist is tired, but asking me to pay for streaming seems reasonable. \$8 seems like a good deal. (On a related note: I pay for other services I receive, like hair cuts. Except that I spend way more than \$8 per hair cut).
• \$8 per month to watch streaming versus \$50 for cable. I pay for streaming. I don’t pay for cable. I feel like I’m saving \$42 per month.
• Streaming is really cheaper than \$8 per month, now that I cut down on the number of discs I rent with Netflix. The marginal cost per month is more like \$4 per month.
• The quality of the Netflix service is fantastic. We have had minimal disruptions and buffering issues.
• The cost of the DVD player I purchased to enjoy streaming was \$8 times the number of months I received free Netflix streaming. It’s like getting a free DVD player.
• Netflix costs less than \$100 per year. It usually costs about \$100 for a marathon entrance fee. There is one main difference: Netflix doesn’t torture me when I watch streaming. I’ve yet to hit “the wall” when it comes to Netflix’s streaming options (That’s the last pun in this post, I promise).
• I don’t understand why so many complain about having to pay \$100 per year for Netflix while shelling out \$1900 per year for cell phone service. But I don’t have a smart phone, so maybe I don’t know what I’m talking about.
• Netflix streaming has no commercials. Let me repeat that: no commercials. These days, we are forced to watch commercials even when we pay for something (e.g., movies in the theater and on some DVDs that don’t let you skip the ads). Double bonus: my kids can watch children’s programming without having to watch sugary cereal and toy commercials. So when my kids watch Sponge Bob, then don’t beg me for Barbies afterward. Sweet.
• Netflix’s streaming catalog is pretty good. I can watch all eight seasons of Monk whenever I want. How obsessively cool is that? Unlike cable, Netflix offers more than just Law & Order reruns and works around my busy schedule.
• Unlike cable and DVD service, Netflix saves my spot when I have to stop a video. I can’t even watch a 22 minute episode of 30 Rock without stopping. I have three kids; it’s inevitable. When I collapse at the end of a long day, I don’t have the energy to load a disc, figure out how to skip the annoying previews, and see if I can remember where I stopped my show or movie. I will, however, lift myself out of my mini coma to start Netflix streaming to catch the end of that 30 Rock episode I wanted to finish. And I think that’s worth \$8 per month.

Have you cancelled your Netflix service?