Monthly Archives: August 2008

The uncanny valley

Check out Seth Godin’s latest post: The uncanny valley. If you find this photo disturbing, read Seth’s article to see why.

Posted in Uncategorized

Random inequalities VI: gamma distributions

This post looks at computing P(X > Y) where X and Y are gamma random variables. These inequalities are central to the Thall-Wooten method of monitoring single-arm clinical trials with time-to-event outcomes. They also are central to adaptively randomized clinical

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Posted in Clinical trials, Statistics

Two posts on reproducibility: art and oceanography

On my other blog, Reproducible Ideas, I wrote two short posts about this morning about reproducibility. The first post is a pointer to an interview with Roger Barga about Trident, a workflow system for reproducible oceanographic research using Microsoft’s workflow

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Posted in Computing, Science

NaN, 1.#IND, 1.#INF, and all that

If you’ve ever been surprised by a program that printed some cryptic letter combination when you were expecting a number, you’ve run into an arithmetic exception. This article explains what caused your problem and what you may be able to

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Posted in Software development

Interactions

Jeremy Freese had an interesting observation about interactions in a recent blog post, responding to a post by Andrew Gelman. Anything that affects anyone affects different people differently. Freese was making a point about statistical modeling, but his comment is

Posted in Uncategorized

PowerShell posts classified

Here’s a summary of the blog posts I’ve written so far regarding PowerShell, grouped by topic. Three posts announced CodeProject articles related to PowerShell:  automated software builds, text reviews for software, and monitoring legacy code. Three posts on customizing the

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Posted in PowerShell

Different kinds of software complexity

It has always seemed odd to me that computer science refers to the number of operations necessary to execute an algorithm as the “complexity” of the algorithm. For example, an algorithm that takes O(N3) operations is more complex than an

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Posted in Software development

Stopping trials of ineffective drugs earlier

Valen Johnson and I recently posted a working paper on a method for stopping trials of ineffective drugs earlier. For Bayesians, we argue that our method is more consistently Bayesian than other methods in common use. For frequentists, we show

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Posted in Clinical trials

Exponential growth doesn't mean what you think it means

When I hear people talking about something growing “exponentially” I think of the line from the Princess Bride where Inigo Montoya says You keep using that word. I do not think it means what you think it means. When most

Posted in Business, Math

PowerShell output redirection: Unicode or ASCII?

What does the redirection operator > in PowerShell do to text: leave it as Unicode or convert it to ASCII? The answer depends on whether the thing to the right of the > operator is a file or a program.

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Posted in PowerShell

Mathematics behind the Olympic water cube

Here’s a post from the blog Continuous everywhere but differentiable nowhere that explains some of the math that was used to design China’s water cube stadium. I found this blog via Carnival of Mathematics #39.

Posted in Math

Medieval software project management

Centuries ago, English communities would walk the little boys around the perimeter of their parish as a way of preserving land records. This was called “beating the bounds.” The idea was that by teaching the boundaries to someone young, the

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Posted in Business, Software development

Who do you call when SOA software breaks?

The idea behind SOA (service-oriented architecture) is that instead of developing monolithic applications, businesses should build “services,” typically web services, that do specific tasks. These services can then be combined in all kinds of useful ways. This is not a

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Posted in Software development

Random inequalities V: beta distributions

I’ve put a lot of effort into writing software for evaluating random inequality probabilities with beta distributions because such inequalities come up quite often in application. For example, beta inequalities are at the heart of the Thall-Simon method for monitoring

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Posted in Clinical trials, Math, Statistics

Statistically significant but incorrect

The Decision Science News blog has an article highlighting a tool to illustrate how often experiments with significant p-values draw false conclusions. Here’s the web site they refer to. See also Most published research results are false.

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Posted in Clinical trials, Statistics