Archive for June, 2009

FPGA that doesn’t use a global clock, but rather “message passing” in hardware to achieve synchronization.

http://www.edn.com/index.asp?layout=blogpostPrint&blog_post_id=1040033304
“The tale starts with one of the less popular approaches to asynchronous logic: two-wire signaling with a separate acknowledge wire, also known as three-wire asynchronous logic. (A big hint toward what Achronix architects have been up to appeared in IEEE Computer Society transactions in 2004.) In this system, when a logic gate creates an output, it codes the 1 or 0 on two separate pins. That allows for three active states: 1, 0, and no-signal. The next gate in the net is designed to wait until the no-signal states of all its inputs have turned into unambiguous 1s or 0s before acting. Once the gate has satisfied its hold time, it sends an acknowledge signal back up the net to the sources of the inputs, allowing them to move on to their next state.

In this way an entire logic net is self-timed. Signals propagate through the network limited only by wire delays and the time it takes each logic element to actually do its work. As soon as all of the inputs have arrived at a LUT and it has received Acknowledge signals from all the inputs it fans out to, it will look up the correct output and transfer it to its output pins, and signal the LUTs that created the input signals that they need wait no longer. The effect is similar to a technique known as wave pipelining that allows pipelines to operate without the use of internal latches.”

The problem of tag divergence is being addressed by an approach between full on semantic web ontologies and open ended tagging. Actually there are ontologies behind this, they’re just hidden from mortal eyes.

http://www.commontag.org/Home

“Let’s suppose you uploaded some pictures of a trip to New York City to an online account. Do you tag them “New York City,” “NYC,” “newyork,” or all of the above? How do you know your content will be correctly identified and related to other content on the web? And if you come across the tag “Tesla,” how do you know whether it refers to the scientist, the car company, or the band?

According to the Common Tag website, “The Common Tag format was developed to address the current shortcomings of tagging and help everyone – including end users, publishers, and developers – get more out of Web content. With Common Tag, content is tagged with unique, well-defined concepts – everything about New York City is tagged with one concept for New York City and everything about jaguar the animal is tagged with one concept for jaguar the animal. Common Tag also provides access to useful metadata that defines each concept and describes how the concepts relate to one another. For example, metadata for the Barack Obama Common Tag indicates that he’s the President of the United States and that he’s married to Michelle Obama.”

http://www.readwriteweb.com/archives/common_tag_brings_standards_to_metadata.php