A useful tool for writing

Check this out! an online tool for looking over text we write and scoring it for readability. Try it on the next memo or blog post you crank out, and weep! When you’re done weeping, tighten up your writing! http://www.hemingwayapp.com/

New emailer services

Here are a couple of emailer services. https://madmimi.com/ This one needs investigating. http://mandrill.com/ This provides an API, and a WordPress plugin called wpmandrill. It’s a freemium service allowing up to 12K messages per month unpaid. It integrates nicely with WordPress, and provides pretty good SPF and DKIM email-authentication support.

SQL Reporting by time intervals

A version of this article specific to the Oracle DBMS is here. It’s often helpful to use SQL to group information by periods of time. For example, we might like to examine sales data. For example, we might have a table of individual sales transactions like so. Sales: sales_id int sales_time datetime net decimal(7,2) tax … Read more

Stored function for haversine distance computation

In another article I described the process of using MySQL to compute great-circle distances between various points on the earth then their latitudes and longitudes are known.  To do this requires the formula commonly called the haversine formula. It’s actually the spherical cosine law formula, and is shown here. There’s a more numerically stable formula — … Read more

Mean Absolute Deviation

Nassim Taleb wrote a provocative article on Edge.Org calling for using the Mean Absolute Deviation in place of the more popular standard deviation as a measure of the variability of a collection of observations. His reasoning is persuasive to me, especially his claim that the standard deviation is widely misapplied and misunderstood. MySQL (like many … Read more