The images show an original picture and a re-imagining of it using whole images found on Flickr. This has been done before at the pixel level where images are picked for their approximation to the pixel in overall color and brightness. Using a coarser granularity, however, produces a much more interesting image. Chris, my wife and artist, likens the result to the the value of chemicals found in the human body.
Technically, it is also a fantastic use of Hadoop. Hadoop is an implementation of the MapReduce algorithm made famous by its use in Google's software.
Why are natural numbers still used for primary keys?
Most database products have a facility for creating unique numbers. These numbers are commonly used as the primary key of a record. You can often see this exposed as a small integer in the URL of a web page. This posting is not about the risks of exposing primary keys but rather about why natural numbers are still used for primary keys.
The observation I want to make is that 1234 can easily be mistaken for 1324. Suppose I have equal access to both the records associated with 1324 and 1234, what mechanisms prevent or at least hinder me or my agents using of the wrong one?
UPCs numbers are numeric but not natural numbers. Credit card numbers are numeric but not natural numbers. ISBNs numbers are numeric but not natural numbers. Each of these are examples of identifiers exposed as "numbers." These identifiers have useful characteristics. They are self validating so that some transcription errors invalidate the identifier. Some identifiers are self correcting. And in the vast universe of value for, for example, 13 digit numbers only a small fraction of the values are valid ISBNs.
As ever more systems record URLs as references to data we need to be ever more careful about our identifiers. Public identifiers should not be natural numbers. Perhaps any system of identification that does not require ordering by identifier should not use natural numbers. It is time that database products had a facility for creating and using unique identifiers that is as easy to use a sequence table or an automatically incrementing integer. Until then, add a check digit.
ISBNs are not stricly numeric as the check digit might be 10 and this is represented as "X".
The observation I want to make is that 1234 can easily be mistaken for 1324. Suppose I have equal access to both the records associated with 1324 and 1234, what mechanisms prevent or at least hinder me or my agents using of the wrong one?
UPCs numbers are numeric but not natural numbers. Credit card numbers are numeric but not natural numbers. ISBNs numbers are numeric but not natural numbers. Each of these are examples of identifiers exposed as "numbers." These identifiers have useful characteristics. They are self validating so that some transcription errors invalidate the identifier. Some identifiers are self correcting. And in the vast universe of value for, for example, 13 digit numbers only a small fraction of the values are valid ISBNs.
As ever more systems record URLs as references to data we need to be ever more careful about our identifiers. Public identifiers should not be natural numbers. Perhaps any system of identification that does not require ordering by identifier should not use natural numbers. It is time that database products had a facility for creating and using unique identifiers that is as easy to use a sequence table or an automatically incrementing integer. Until then, add a check digit.
ISBNs are not stricly numeric as the check digit might be 10 and this is represented as "X".
RI, go vote today for Barack Obama
My reasons for supporting Barack Obama are my two 8 year old boys. The next president is likely to leave office when they are 16. I want these years for them to see America at its best. I want them to see and experience leadership that rights wrongs. I want them to experience an optimistic America. I want them to participate in an optimistic America. I fully expect the next years to be difficult for this country. I believe that Barack Obama can lead us through this hardship.
New Common's working space
Last week I spoke with Robert Leaver and Michelle Gonzalez at their New Commons offices. It was a great conversation and one I hope to continue. Robert's and Michelle's manner and their working space immediately make you relaxed. I am usually confident and comfortable in new situations but the feeling of welcoming there was intense.
Their working space is very well designed. Robert's work creating spaces and places would of course lead you to expect this. Here is my rough [*] floor plan of the space. I particularly liked the open hallway and the offices's French doors onto the meeting space.
[*] Visio's floor planning tool is very easy to use. However, the formality of the final visual hides too well the inaccuracies of dimensions and the mistakenly forgotten or added features.
Their working space is very well designed. Robert's work creating spaces and places would of course lead you to expect this. Here is my rough [*] floor plan of the space. I particularly liked the open hallway and the offices's French doors onto the meeting space.
[*] Visio's floor planning tool is very easy to use. However, the formality of the final visual hides too well the inaccuracies of dimensions and the mistakenly forgotten or added features.
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