Prisoner’s Dilemma Denim Style

At work denim was removed from the acceptable dress code. No worry to me because I could not remember the last time I actually wore jeans to the office. They are not clothes I wear often away from the office either. Even in “cold” weather (above freezing, below room temperature) I sweat in them. I find them uncomfortable to wear while sitting. So I pretty much only wear them when I am going to spend time in freezing weather and not at the office. Losing the authorization did not bother me much.

Your area has been assigned a denim dollar collector for “Denim Days” starting ******.   Each [certain weekday] your denim dollar collector will visit to see if you or everyone in  your area is wearing denim.   If everyone in your area is wearing denim the cost will be $3.00 per person, if not, the cost will be $5.00 per person.

I wonder if people know this is a more complex version the Prisoner’s Dilemma in game theory.

Tucker began with a little story, like this: two burglars, Bob and Al, are captured near the scene of a burglary and are given the “third degree” separately by the police. Each has to choose whether or not to confess and implicate the other. If neither man confesses, then both will serve one year on a charge of carrying a concealed weapon. If each confesses and implicates the other, both will go to prison for 10 years. However, if one burglar confesses and implicates the other, and the other burglar does not confess, the one who has collaborated with the police will go free, while the other burglar will go to prison for 20 years on the maximum charge.

The strategies in this case are: confess or don’t confess. The payoffs (penalties, actually) are the sentences served. We can express all this compactly in a “payoff table” of a kind that has become pretty standard in game theory.

In this case, cooperation is both confessing (example) and wearing denim (situation). Defection is both not confessing (example) and not wearing denim (situation). Unlike Prisoner’s Dilemma there is not a middle point where both defecting has the second best result. Also, one has to anticipate whether 3-30 people all cooperate not one other. According to game theory, it is in everyone’s interests to cooperate which means wear the denim.

Unfortunately, there is a plausible third choice which may derail the whole thing: refusing to pay anything. Wearing jeans and not paying would still be unauthorized as the point of the activity is to raise money by letting people participate. However, forcing people who do not wish to participate seems like a Human Resources disaster waiting to happen. Yet, the game is predicated on universal participation. Hopefully, when there is push back from people like me they just strike those refusing to play along from the activity as non-participating and do not punish all the members of the group by making them pay for a non-participant.

BTW, Denim supposedly could mean “de Nîmes” aka “of Nîmes” a city in France. (Wikipedia / Yahoo news) I didn’t go into scholarly research to determine whether that is true.

Night School

I noticed a couple weeks back there are interesting spikes in the evening hours of Sunday through Wednesday. Just like morning/afternoon usage, the evening spikes diminish but even more so by comparison.

As I recall for Monday through Wednesday, when I first started, the evening traffic almost flatlined at 5pm and then dropped off at 11pm. Over time the spike has grown to the point we have more users active in the evening than during “business hours”.

In this graph, the numbers across the bottom are the week of the year. The numbers along the left side are the number of users active within the last 5 minutes.


Really I have no data to say why the change in trend. (We are not 100% online and the majority of the classes we host are supplemental to face-to-face, with hybrid and totally online fighting for second place.) I hope the days of instructors teaching in a computer lab and having students follow along died a hard painful death. If so, then the amount of activity during the day would lessen some. Students and faculty would still go online during the day between classes. However, more student access to broadband at home would empower them to go online more often in the evening and increase the difference between day and evening user activity.

Identifying where each individual IP resides is hard. Doing so for many is more time than I would want to invest in the question. Campus vs. residential vs. corporate is relatively easy. However, “home” for a student could be on campus or residential. Maybe someone else knows better than me.

I guess this means we really ought to look at our automated operations which kick off at 10pm. WebCT recommended they be run when user activity is light or they could impact performance.

Ender’s Shadow

This paragraph really resonates with me. So I wonder which a new factor disrupting my life falls under: comfortable/liked or quiet/blamed.

They were career military officers, all of them. Proven officers with real ability. But in the military you don’t get trusted positions just because of your ability. You also have to attract the notice of superior officers. You have to be liked. You have to fit in with the system. You have to look like what the officers above you think that officers should look like. You have to think in ways that they are comfortable with.

The result was that you ended up with a command structure that was top-heavy with guys who looked good in uniform and talked right and did well enough not to embarrass themselves, while the really good ones quietly did all the serious work and bailed out their superiors and got blamed for errors they had advised against until they eventually got out.
Card, Orson Scott. Ender’s Shadow.

Higher education is similar. Graduate students have to make professors comfortable with the thought of the student joining a higher rank or face being blamed for why the research or teaching is substandard. Technology is even more similar. Things do fail, people will be blamed unless someone higher up protects the front line people. The question is: When the front line people pointed out what was needed to be successful and higher ups hedged bets by choosing higher risk over higher costs, will the front liners be blamed when things fail?

We like to pretend logic forms the basis for our decisions when really the decisions are based on manipulated emotions. Those we like we protect. Those we have no bond we cut loose. I just wish people were more forthcoming about the reasoning behind decisions.


Unusual names intrigue me. Whenever I encounter a name I don’t know, I find myself curious about the origin. Probably this comes somewhat from researching my own names which both my first and last (see the last post Legacy of a Name). Both were for obscure authors and painters people almost never know. Which lets me explain who they are.

Asked a waitress named Sabra if she knew the origins of her name. She had never looked it up, but multiple bank tellers told her it was the name of a desert flower in Arabic. She found it interesting bank tellers are the only people who volunteer that they know about something non-monetary. Told her about my recent discovery Ezra was an anti-miscegenist so my pro-miscegenist parents ironically named me for him. We both laughed about the story.

So I looked up sabra….

The Akkadians used a word sibaru for aloe. Arabic picked it up as sabr. Hebrew picked up the word for cactus in with the introduction of the prickly pear as tzabar. In 1931, Sabra was adopted to mean those Hebrew born in Palestine and distinguish them from those born in Germany or Russia. Ezra would have been much in favor of Sabras, I think.

Didn’t expect it to go in that direction. At least the exercise made me laugh.

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Legacy of A Name

There is a legacy of my name most people may not be aware.

Ezra the Scribe made all the men of Israel send their foreign wives back to Persia. See, the people had been living in Babylon in Persia (now Iraq). Cyrus, founder of the Persian Empire, allowed them to rebuild the temple in Jerusalem (the same one whose current ruins form the basis of the animosity of Islam vs Israel) following a dream. His grandson, Darius, allowed the Israelites to return. One of the better known repercussions of reconnecting the people with the Word was to make the men give up any foreign wives to send back to Persia.

10 And Ezra the priest stood up, and said unto them, Ye have transgressed, and have taken strange wives, to increase the trespass of Israel. 11 Now therefore make confession unto the LORD God of your fathers, and do his pleasure: and separate yourselves from the people of the land, and from the strange wives.

This is definitely about separating different races, seeking to accomplish the same thing as what Loving vs. Virginia overturned. So there is a certain amount of irony being indirectly named for an anti-miscegenationist when just a couple years prior my parents found difficulty getting married over them being of two different races. Of course, my mother was proud of making John C. Calhoun roll over in his grave by having me… So….

We Remember

Today is the day many Americans will signal (any nonverbal action or gesture that encodes a message) their nationalism by displaying pictures of the World Trade Center, the United State flag, NYFD logos, or yellow ribbons. Given the current climate, such signalling probably is wise as anyone like me who fails to appropriately signal can be viewed as a traitor. Unwilling to explicitly state hate and needing to show solidarity with those who do, people will opt for the subtle support.

I remember feeling sad for families who lost loved ones.

I remember hoping few of those who witnessed the events had sufficient emotional support and would avoid suffering Post Traumtic Stress Disorder.

I remember people writing or sayings the only terrorists are Muslims. They were completely oblivious that Timothy McVeigh was executed 3 months to the day earlier for committing the most recent terrorist bombing on United States soil.

Of course, I blogged about 9/11.

Anger, hate, and fear are destructive emotions. Nothing good comes from them. Good comes from deciding to go beyond them. Until then the terrorists really have won.

When To Upgrade

After Firefox just upgraded, I noticed it did a check to on the compatibility of the Add-Ons I have. Should any be incompatible, then the add-on gets disabled. The rationale being, “Add-Ons which do not work under the current version should not be enabled.”

Seems like I as the user of the software really ought to have a choice:

  1. (Current) Immediately upgrade the browser and disable any incompatible add-ons.
  2. Check add-on compatibility first and delay the browser upgrade until add-ons are all compatible.
  3. Check add-on compatibility first and prompt the user to choose when to upgrade. (Whether #1 or #2 is desirable.)
  4. Allow the user to choose which add-ons are too important to be disabled and delay the browser upgrade until an add-on version is available which is compatible. Then offer to upgrade both.

Maybe not enough people care Mozilla takes away their functionality?


I’ve imported my blog posts from Vox. As a service, I liked the concept: A highly social rich media blog site. My hopes it would take the place of LiveJournal never came to pass. My use of it to pretty much devolved to a secondary place to post my Flickr photos. (Of course, that is all I use LJ for these days as well.)

Verify Node Has War Update

Last week I posted on how to verify the cookie domain on nodes not just looking in the Ear file on the admin node. That same concept has another cool use: Verifying which VSTs the nodes actually have.

Typically one-off updates from Blackboard has us run the updateWebctEar to replace classes in the war file. In a nutshell it…

  1. opens the ear
  2. opens the war
  3. updates the class at the path
  4. regenerates the war
  5. regenerates the ear

Simple enough by hand, but very convenient in a script. I was glad when Bb gave us this functionality.

./ updateWebctEar __some_class.class webct.war/WEB-INF/path/to/class

Verifying that this is in the Ear file is rather easy, but it takes a while manually. Also, one of the steps is to open the ear then search the webct.war. Well, the managed nodes cache the Ear so it kind of saves a step to look there. We run 14 clusters and worry about inconsistencies between various development clusters and between development and production. Plus, as this is a sanity check, why not check all of them? (Also, we use dsh, so checking all 140 production nodes with one command and not having to login to each saves the most time.)

The command…

  1. changes directories to a location in the cache area,
  2. confirms the location
  3. uses the Java ARchive (JAR) tool to list (-t) verbosely (-v) the webct.war file (-f)

All put together…

&& pwd && $JAVA_INSTALL/bin/jar -tvf */webct.war WEB-INF/path/to/class/__some_class.class

The output looks something like below. The time stamp appears to be when the server administrator added the file to the

118864 Fri Jul 23 11:25:42 EDT 2010 WEB-INF/path/to/class/__some_class.class

I’m thinking this could also be useful to scan for what updates the nodes have in the War just after we’ve installed it.