So let's get to some good economic news. ABI research is saying that markets for pulsed RF power devices below 4 GHz are expected to show continued solid growth over the next five years despite the current economic turmoil. While the volatility of many global electronics markets is fueled by their association with consumer spending, markets for pulsed RF power devices are supported by quite different priorities.
�Many RF power semiconductor manufacturers are on a quest to find markets unrelated to mobile wireless infrastructure,� notes ABI Research director Lance Wilson. �Device prices in wireless infrastructure are falling, and the total available market is shrinking.�
Some markets that use pulsed RF power devices, such as the transportation safety market and the military market, are seeing good solid growth even in the midst of today�s economic downturn. These devices are used in radars for military and marine applications, and in a worldwide upgrade of the air traffic control system that is now occurring. There is also a market segment devoted to the avionics transponder and air navigation market, which is also lifted by the air traffic control upgrade.
I know there are several companies going after the air traffic control system upgrade and I think this is a necessary upgrade that should provide sizable contracts for many suppliers in the years to come.
Google Code Jam's Ranking Library Released
At Google, we like to use our own projects for internal development. Following that philosophy, one of the first apps ever made for Google App Engine was the contest platform for Google Code Jam. The application was a good fit: a rich web interface, real-time user interaction, and a heavily parallel design. But we faced one major challenge, which was how to handle the huge scoreboard -- in the first round, we had over 11,000 contestants.
While App Engine's datastore allows you to sort entities by score, it doesn't have a built-in mechanism to answer the following two requests:
- Given a user, what is his or her rank on the scoreboard? In other words, for some arbitrary row in that scoreboard, what is its position amongst the 11,000 spots? This is useful for showing your own rank, as well as the ranks of your friends.
- Give me all users on the n-th page of the scoreboard. While it is possible to get all users in sorted order, datastore queries don't allow you to start at page n, and iterating over all of the users on the first n pages takes too much time.
To solve these issues, we came up with a library that maintains a data structure to efficiently support these use cases. We imagine that other applications will have similar problems (e.g., a high-score list in a game), and so we're happy to release our work as the "google-appengine-ranklist" library.
The library supports three different operations:
- Setting the score of a given user.
- Given a score, what's the rank of a user with this score? This is used to answer the "What's the rank of person U?" use case.
- Given a rank, what's the score S for this rank? This can be used to solve the paging problem, by constructing a query that returns the first few users with a score less than or equal to S, in sorted order
If you think this library could be useful for you, take a look at the documentation and at the example application. We'd love to hear from you in our Google Group.
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