Saturday, January 31, 2009

Amtgard News #3

Since our group is looking for new people, I have came up with an interesting way to try to recruit new people. I am walking around the campus in garb and chainmail. carrying around flyers and handing them out to people who ask me about my outfit. Some of the rest of the group members didn't think that that would work, but they were wrong. Over a period of two days I distributed about 80 flyers, including those I handed out to people and those I put up on bulletin boards.

Today, a new guy came who said he had participated in LARP before and was interested in joining us. He found my flyer in the math department lounge. Also, a photographer from a journalism class came up and asked to take some pictures for a project because he had seen my flyer. Finally, while I was in the dining hall dressed in garb a reporter from the Diamondback approached me and asked what was going on. I told him about the game and he said he wanted to come out and see us fight and do a story on us.

Monday, January 26, 2009

Friday, January 23, 2009

First week at the Census Bureau

So today is the end of my first week at the U.S. Census Bureau.

Monday and Tuesday, the Census Bureau was closed because of Martin Luther King Day and the inauguration. (Although apparently I still get paid for those days!)

Wednesday and Thursday was orientation. Yes, it lasted two full 8-hour days. Most of it was pretty mundane presentations, a lot of which didn't even apply to me because I am a part-time worker (like the presentations about health benefits, retirement plans, etc.) However there were a couple funny parts, like the presentation about "Government Ethics." Normally, of course, you can teach government ethics just by opening up the newspaper to a random page. However, since this was the day after inauguration, all the newspapers were filled up with inauguration news, so we learned about government ethics by watching a video entitled "The Battle for Avery Mann," which features a nondescript government worker in a nondescript office facing a series of ethical conflicts (whether to use the office copying machine for personal use, whether to accept gifts from a subordinate, what to do when asked to review a proposal from a company he also works for part-time) and two comical characters representing his good and evil impulses trying to tell him what to do.

On Friday, I started doing some actual work. I am working in the Statistical Research Division in the Disclosure Avoidance Research Group. The goal of this research group is to find ways of releasing census data to the public in a way that is useful to potential users of the data, but that does not enable anyone to find out any information about a particular respondent. Methods that are being used now, or being explored for potential use in the future, for doing this include:

1. Providing only certain cross-tabulations of data, not the full data set.
2. Suppressing cells in cross-tabulations with less than a certain number of people in them.
3. Adding artificial "noise" to certain elements of the data set.
4. Providing a synthetic data set with similar statistical patterns to the real data set (say, the same values for all cross-tabulations with up to a certain number of variables) but that doesn't have any of the real data.

To see some of the work the Statistical Research Division does, you can see research papers they have published here. I am working with Yves Thibaudeau and Robert H. Creecy.

Bonus Math Question:

The Census Bureau offers a benefit known as a "health savings account" (HSA). Employees can designate a portion of their income to go into the HSA pre-tax (meaning that money put into the HSA is deducted from your income for purposes of income tax). Money in the HSA can be used for health care expenses. However, any money left in the HSA that is not used for health-care expenses is lost.

How can you determine the optimal amount of money to put in the HSA? (Assume that you are risk-neutral, that your utility of money does not depend on your health care expenses, and that you know what your probability distribution of health care expenses for the next year looks like.)

Thursday, January 22, 2009

Not everyone has a dirty mind

I was telling Tanya today about the Capitol Steps performance I went to. The conversation was something like this:

Me: One of the Capitol Steps skits had Barack Obama asking Hillary Clinton if she was happy with her "new position", meaning secretary of state. Then Bill Clinton walks in and says, "New position? Did somebody say something about a new position? Why wasn't I told about this?"

Tanya: I get that joke. It makes sense. I was watching Hillary Clinton on TV, accepting the position as secretary of state, and I could just picture Bill Clinton walking up there, wanting that job.

Me: No, I think the joke was that he thought it was "new position" as in sexual position.

Tanya: Yeah, I guess that works too.

Monday, January 19, 2009

Realism in Video Games #1

This will be the first in an upcoming series of blog postings about features of video games that model reality a little more closely than was probably intended.

For the first one, it's best to go to the primary source and look at this quest description from World of Warcraft:

The Art of Persuasion

RPG Math - Problem 5

Problem 5: Mathematically Challenged

Dungeons and Dragons' 4th edition has a game mechanic known as "skill challenges," in which players work together to defeat a challenge that requires using certain in-game skills. Each player's character has a "skill modifier" that represents how good they are at the skill in question, and the challenge has a "difficulty class" (DC) that represents how hard the challenge is. (In the game, there may be more than one skill that can be used for a particular challenge, but this is irrelevant to our analysis because each character can simply use whichever skill he is best at.)

Players go in a circle (order decided on by the players), each one making a skill check. A skill check is made by rolling a 20-sided die and adding it to the skill modifier. If the result is equal to or greater than the DC, the check is successful. For example, if the skill modifier is 7 and the DC is 15, the player needs an 8 or more on the die to earn a success. You continue around the table until 8 successes or 4 failures have been achieved. If the players get to 8 successes first, they win the skill challenge; otherwise, they lose the skill challenge.

A player can also spend his turn to "aid another." This means making a skill check against DC 10. This check does not count as a success or failure. Instead, if it fails, nothing happens and you move on to the next person, while if it succeeds, the next player gets a +2 bonus to his next skill check.

Consider a skill challenge with a DC of 15 and 4 players with skill modifiers of 8, 6, 4, and 2 respectively.

(a) What is the optimal way to use "aid another" to maximize the chance of winning?

(b) Suppose that we want to make "aid another" less powerful by increasing the difficulty of the aid another check from 10 to a higher number. In this particular challenge, how high would we have to raise the difficulty to make never using aid another the optimal strategy?

(Author's Note: This problem has some minor differences from how skill challenges actually work in D+D, but these differences do not change the overall conclusion.)

Answer is here.

Amtgard News #2

So, a lot interesting has happened in Amtgard since the last time I posted. First, we had Coronation on the 10th. It was the usual stuff, with some ditching, a feast, and an auction. Some of the stuff I got from Vietnam fetched a reasonable sum ($40 for a robe I originally got for $18, and $17 for some vases I originally got for $3).

On the 17th, we didn't have much going on because only two people, me and the Monarch, showed up. We knew turnout would be low because some of our members were visiting other parks, but we didn't expect it to be this low. Then we called another member, Pict, who said he was going to show up but didn't because it was too cold, but agreed to meet us at Plato's, a diner, to have food and talk. He revealed that there would be a big coronation event on the 18th for Crystal Groves, and that he wanted to go but had no money for gas. I offered to pay for his gas if he could take me and he agreed. Unfortunately the next morning he had a pain in his back and had to go to the emergency room, so that plan was canceled. (Instead I spent the day in Washington, D.C., where I saw the new, remodeled, American History museum, went to the Madame Tussaud's wax museum, bought a couple Obama T-shirts, and saw a Capitol Steps performance. Judging by the number of vendors selling Obama merchandise, Obama has already begun stimulating the economy.)

On the 24th, we will have the "Defense Contractor" game, where we will all compete to make weapons to fulfill "contracts" I post and make money (in gold pieces), and the team that makes the most money at the end of a given time period wins. (One of our members works for a defense contractor in real life, and thought my game was a good idea.)

Thursday, January 1, 2009

Dispatches from Vietnam: #3 - Lawsuit Culture (or lack thereof)

I just got back from a two-day cruise in Halong Bay, a bay a few hours outside of Hanoi. Rather than repeat a lot of information, I'll just point you to the post my mom posted on her blog about it that has lots of pictures.

But there was one interesting cultural difference we noticed. Throughout the trip we remarked on how if we were doing this in the United States, we would have to wear life vests everywhere we go, and we would have to sign all sorts of waivers. It really does make you think about how much more "lawsuit happy" our culture is than many others. (Of course, if the alternative is to beat people up, as I mentioned a couple blog posts ago, it may not be so bad in comparison.)

This issue does, however, give me an opportunity to blog about something that I thought would be an interesting topic but didn't really have the occasion for. And that is, just how good is our "lawsuit culture" at deterring harmful behavior? Consider the following real-life scenarios:

1. The Amtgard kingdom of Crystal Groves has liability insurance. It got this insurance because it was required to by the park it plays at. (Many, if not most, event sites will require that people renting them out have liability insurance. Even though Crystal Groves usually plays at a public park, the park still required them to have insurance.

IIRC (If I remember correctly), this insurance costs about $1,600 per year for a kingdom of about 200 people (maybe less, I'm not sure exactly). Additionally, the insurance company offered to extend it to our own barony of Solstice at a cost of $1 per person per year. Assuming that the actuarial value (i.e. the actual expected amount of losses from injuries or lawsuits) is approximately proportional to the number of people, and this offer was not a money-losing proposition for the insurance company, the actuarial value of the original policy is at most about $200 per year. In other words, almost 90% of the cost goes to administrative costs and profit for the insurance company, not actual compensation for risk. (And even the other 10% consists partially of court costs and other expenses not related to actual treatment of potential injuries.) Is this really the most efficient system?

2. The built-in navigation system on the Toyota Prius is designed with a feature that prevents it from being operated when the car is in motion. The purpose of this is to prevent drivers from taking their eyes off the road the use the navigation system. Of course it also means that even if there is a passenger in the car, he can't use the navigation system. (This could even reduce safety in some situations: let's say you're on a highway going 70 mph and you have to pull over, program the navigation system, and merge back into highway traffic.) On 2005 and earlier models, there was a hidden menu that enabled the user to override this lockout. After users discovered this, it was removed from later models. Currently, there are companies that sell devices which can be installed in the Prius that will override the lockout on newer models.

Effectively, Toyota is engaged in an arms race against its own customers in an attempt to reduce the functionality of its product in order to avoid lawsuits. One solution would be if it was possible to sign a legally binding waiver to not sue due to accidents caused by using the navigation systenm, and if you signed that waiver then they would unlock the navigation system for you. But of course if you actually signed a waiver like that, it would probably not be upheld in court. Effectively the consumer's inability to credibly commit to not suing hurts them, because it stops them from using the navigation system (or forces them to buy costly insurance, in the case of the first scenario above).