Mar 17, 2014

A New Coverage Concept

posted by Bryon Moyer

OneSpin announced a Quantify MDV product a few years back. With it, they defined a number of different coverage aspects – things that could be verified with their formal technology. Now they’ve reinforced that product with a new version. And that version contains yet another coverage concept.

The older coverage concepts focused on the design itself and the quality of stimulus used in verification. It would check for things like dead code and over-constraining, the former reflecting a possible code issue and the latter indicating that legitimate cases may not be covered by existing tests. I discussed these elements in my original coverage of the tool.

In recent times, they struggled a bit with what to call these checks. You might think they’re simply “design” checks, except for the constraining bits. The aspect that gets to simulation coverage had them calling it “simulation” coverage, but that didn’t really cut it either. They landed on “reachability,” since things like dead or redundant code indicated design elements that may or may not be reachable, and the constraints also get to whether or not certain failures can be reached by the tests. It’s not a perfect nomenclature, but, absent something perfect, it’s what they settled on.

Why even worry? Well, they needed to distinguish all of those coverage aspects from a new one they were adding. This new one tests the completeness of the assertions and checkers in the design. The assertions are designed to catch problems during formal verification, but it’s possible to write ineffective assertions. Looked at another way, if assertions are poor or incomplete, then there may be code failures that could never be observed by the assertions.

So they refer to this as “observation coverage.” And they test it using a form of “mutation” analysis: making a code change and seeing if the assertion picks it up. If not, then there may be a hole in the assertion.

This appears to be a newish concept, and it’s not comprehended in the UCIS coverage standard; they’re in discussions on that.

You can get a more complete picture of their latest Quantify release in their announcement.

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Mar 12, 2014

Clearer Phone Conversations

posted by Bryon Moyer

I recall the few times I was able, for some reason, to take advantage of noise-cancelling headphones on an airplane. Once on your ears, when you turned them on, you gradually heard the background hiss of the airplane disappear. It took a few seconds for this to happen.

My assumption was that this was a slow integration problem, and that only long-term constant sounds could be cancelled out; the circuitry simply wasn’t fast enough to eliminate short, sharp sounds. (Which is probably good, since you certainly wouldn’t want it to cancel out important flight attendant messages, like the fact that you can get a great deal on a credit card or that duty free is now available).

This means, of course, that such headphones wouldn’t solve the “cocktail party” problem: isolating one voice and dimming the others, something our ears and brain somehow manage effortlessly.

Solving that would be particularly nice on our phones; as Cirrus Audio points out, if you use the phone in a bar, all voices go through, not just yours.

Of course, headphones on an airplane don’t include a microphone. With a phone, even if you had super-fast algorithms that could cancel short, bursty noises, you’d need to avoid cancelling out the person speaking into the phone. That would kind of defeat the purpose.

Cirrus recently announced some new devices dedicated to improving phone sound, and noise reduction and cancellation are part of it. Phones are moving to multiple microphones to figure out which sounds to suppress, but the audio guys have a challenge in that they don’t get much influence over where those microphones go. So Cirrus is trying to be as adaptive as possible.

They claim that most other audio chips are pre-optimized and fixed, while, by contrast, they dynamically adjust their noise reduction/cancellation to adapt both to the phone and the specific sound environment. And their noise reduction applies to both ends of the conversation – the voice at the phone and the voice at the other end of the line. (And if you think that solving the noise at one end makes solving it at the other unnecessary, you haven’t listened to cell phones much. Although apparently cellular systems are moving to wideband voice so that whe_ _he voi_ isn’t drop_g out, it wi_ sound _reat.)


The other bit that caught my ear was their approach to voice recognition and control. This gets to the always-on problem: if your phone is going to be voice activated, then you want that to work without your having to turn the phone on first. If the phone goes completely to sleep, then this won’t work.

But having the phone on all the time kills the battery. So Cirrus has a three-step wake-up routine. A low-power block listens to determine if there’s a significant sound. If so, it wakes the next block, which determines whether or not the sound is noise or a voice. If it’s a voice, then the third step wakes up, which does two things in parallel: decodes the command and decides whether it’s the authorized voice. If it’s not an authorized voice, then the phone automatically responds, “You’re not the boss of me!” and goes back to sleep with a righteous pout.

OK, maybe not quite like that… that might be a cool feature, though, in case you product planning guys are listening…

Anyway, you can find more details in their announcement.

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Mar 10, 2014

Internet of Things- This Season's Trend

posted by Dick Selwood

Later this week I will be reporting on the embedded world conference, where the Internet of Things was the major topic. Just before embedded world was Mobile World Congress, which has become as big a circus as the Consumer Electronics show. There again the Internet of Things was a huge topic.

Today CeBIT opens in Hannover. Once just a specialist computing exhibition and conference, spinning off from the massive industrial exhibition of the Hannover Fair, it too has become enormous. And last night at the opening of the fair by Chancellor Merkel of Germany, the British Prime Minister, David Cameron, announced that the British Government is going to invest £73 million (around $120 million) in research in areas linked to the Internet of Things.

Perhaps not entirely by coincidence, several of the heavy weight British Sunday papers devoted several pages to explaining the Internet of Things to their readers. With all this hype it has the appearance of being another tech bubble. But it would be wrong to dismiss it as that. Whatever the public gesturing, interconnectivity, remote access to monitor and control domestic appliances, and all the other things that are pouring into the Internet of Things soup, these form a trend that is not going to be reversed. The job for engineers is surely to make sure that as these things come together they are secure, safe and reliable

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