Sony Reader and Mac

The Sony Reader is not designed to run on the mac, but there is a simple workaround.

###[October 30, 2009] Update: The Sony Library has finally been released for Mac. So the text below might not be relevant anymore###

It is possible to download DRM-protected EPUB and Adobe Digital Editions formatted books to a mac and then transfer it to Sony Reader via usb.

Just once, one must go through the following process.

The two pieces of software, Sony Library and Adobe Digital Editions, must be installed on a Windows PC computer. Connect the Reader to the PC. From within Adobe Digital Editions, authorize the reader.

Now install Adobe Digital Editions on the Mac. Buy an EPUB or Digital Editions book from, say, www.booksonboard.com. The book can now be read on the mac through the Adobe Digital Editions software, while the file itself is found in Documents/Digital Editions/.

Connect the Sony Reader to the mac. Drag and drop the .epub or .pdf file from the mac folder to the Sony Reader. Done.

Do I think that Amazon, Sony and the book publishers are doing a good job of making it as painless as possible to buy and read ebooks? No. Please give us one open standard for ebooks, get rid of digital rights management and make all books available to everybody all the time through a new revenue model. 60 years from now, I do not want to discover that my precious ebooks are lost, since the rights management server has perished and no current technology can read the proprietary format.

Business Management Through Customer Lifetime Value

A company's customer base can be thought of as a collection of stochastic future cash flows, not unlike a portfolio of securities. Managers then evaluate the effects of business decisions against expected changes in the present value of customers' cash flows. This is customer lifetime value analysis.

The figure above shows the event histories of a random sample of newspaper customers. Yellow marks a period of rebate subscription, while green marks a full price subscription. Red denotes a period of no subscriptions - the customer has churned. Read more in "Analyzing Customer Lifetime Value Using Tree Ensembles" (link).

Analysis based on the customer lifetime value concept must typically account for two main aspects of customer behavior: The lifetime of a customer and the monetary value generated while active.

Given a set of customer attributes, such as demographic data and past transactions, a model of customer lifetime value can be created. The model seeks to relate customer attributes to lifetime and value.

An example of a basic quantitative approach is to model value through a linear regression model, while lifetime is estimated based on, say, an exponential distribution.

A customer lifetime value model has several exciting applications.

• Resource Prioritization. Sensible lifetime value estimates can serve as a basis for organizational resource prioritization: Customer service level design, marketing spending, sales force pay and so on.
• Novelty Detection. Detect and react to changes in the marketplace by monitoring the formation of new patterns in customer lifetime value. Are former valuable clients all of a sudden churning at higher rates? Are new groups of high value clients forming?

Businesses can differentiate valuable customers at an early point in customers' life cycle, monitor the customer base evolution and act on their data on a systematic basis. Such businesses stand to harvest great rewards.

God, Tax and AI

Today, while walking to a client meeting, I was approached by a man.

Man: Are you interested in talking about God and such?

Me: No, not really. I am more interested in making money.

Man: Is it not strange that the Large Hadron Collider recreates circumstances similar to those during the Big Bang, the creation of our universe. The Hadron Collider was built by intelligent people, then, why shouldn't there be intelligence behind the Big Bang?

Me: I am interested in artificial intelligence and hope to one day build a machine with an intelligence surpassing that of humans. However, I would not want the machine to care about its creator. I would want it to solve problems.

Man: Surely a machine would have no conscience, as man, as is witnessed by his enactment of the laws of society.

Me: Who says that man has conscience, that it is not an illusion? Anyway, I think a machine could be programmed to have conscience. ...And when I look at the tax legislation in this country, I really cannot see that as an expression of conscience.

Reinforcement Learning - Tic Tac Toe

Based on Sutton and Barto's "Reinforcement Learning", I did a simple python implementation of tic tac toe.

The algorithm has no knowledge of tic tac toe, except it knows when it has won or lost. By playing against you and itself it gradually learns how to play well.

This particular implementation does not take "exploratory" steps, but it would be simple to implement.

Python code

Information Diet

Reddit, digg and slashdot, New York Times, Financial Times, Wired, Facebook - you are all quarantined for one week. You take up too much of my non-work time.