Archives for May 2009

Open-Source Data Models?

27 May 2009

What could help people share the models they use for generating data so that others can investigate alternative scenarios or presentations of the model (and not just the resulting data)?

For example, in the The Economics of Structured Finance [pdf], Joshua D. Coval, Jakub Jurek, and Erik Stafford discuss the impact on the value of collateralized debt obligations (CDOs) and CDOs-squared of changes in the default correlation and probability of their underlying assets. They present one graph showing the change in value versus the change in default correlation, and another showing the change in value versus the change in default probability. But they don't show the change in value versus combinations of changes in default correlation and default probability. An open-source model would allow someone to calculate these hybrid scenarios, or even to create a visualization allowing others to explore the model in other ways.

To be relevant, of course, such an open-source model would need to be in a format accessible to those interested in using it. What tools do these models tend to be created in? If these are proprietary and expensive, an open-source model may be useful to other researchers and professionals, but not the broader public. Is it possible to make it easier to create or modify these models in free (e.g. most programming languages) or common (e.g. Microsoft Excel) tools?

Alternatively, it is enough to encourage the distribution of data resulting from such models, in the expectation that a comprehensive data set would enable most or all of the uses of an open-source model?

Update: This week's Planet Money discusses another possible audience for open-source (or, at least, shared) data models: rating agencies and investors. That is, rating agencies could publish the models and calculations they use to determine their ratings - giving investors an opportunity to evaluate their assumptions as well as their final judgements.

Testing "Copy as HTML" in Arduino

24 May 2009
 * Blink - the basic Arduino example.

int ledPin = 13;                // LED connected to pin 13

void setup()                    // run once
  pinMode(ledPin, OUTPUT);      // sets the pin as output

void loop()                     // run over and over again
  digitalWrite(ledPin, HIGH);   // sets the LED on
  delay(1000);                  // waits for a second
  digitalWrite(ledPin, LOW);    // sets the LED off
  delay(1000);                  // waits for a second

What is the potential of open-source hardware?

17 May 2009

This is something that Simona asked me recently. To be honest, I'm not sure what the answer is. I don't expect that a large portion of the population will ever design a circuit or even assemble a kit. But perhaps it can provide for the creation of many products that would not otherwise have existed, and which have the potential of mass consumer appeal. The possibilities for industry are also fascinating, but something I know very little about.

I hope that in a few years I'll have a better answer to Simona's question.