Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?

Comment Re:Anybody in optics? (Score 1) 106

The best way to do this would be to modify the firmware to include some kind of pseudorandom modulation scheme (think binary chip sequence). However, the processor on the Kinect is a PrimeSense proprietary ASIC. Good luck reverse engineering it.

Shuttering might work, but as you said, you'd reduce the overall framerate, meaning worse motion capture. Also you'd need to synchronize the shutters somehow, and that'd be a pain.

Filtering would change the sensitivity of the camera, but it won't do much to the laser. You'd have to swap it out for the specific band you're filtering to. Also, I'm pretty sure optical band pass filters aren't cheap.

My personal hope is that we see some kind of modulation in later versions of the device, either because Microsoft asks for it, or because PrimeSense just starts including it by default in their ASICs.

Comment Re:Too small a jump for a 6 years -- red flags! (Score 2, Insightful) 281

Moore's law (which doesn't work in every way, but it certainly works for the computing processors in this thing) would suggest that this thing has a lot more CPU power than the CRS-1. (In six years we'd expect somewhere between 8 and 32 times the oomph.) And yet they only encumbered it with three times the bandwidth.

Moore's law applies to the number of transistors on an integrated circuit and has absolutely nothing to do with bandwidth. Chip throughput is much more a function of the chip architecture than the number of transistors on chip. Even if chip throughput was somehow correlated to Moore's law, there are still unrelated inefficiencies in the physical layer that are very complex and difficult to overcome.

Comment Re:This ! Is ! GOO-GLE ! (Score 1) 315

Well, all the hardware / processing requirement are moot given it's freaking Google we're talking about.

It's far from moot. Converting their entire video library carries real monetary and time costs that are quite significant -- even to Google. Google is still a business. It would stand to reason that they'd incur these costs only if it made business sense -- that is, if there is some direct or indirect return on investment. We'll see whether or not they find the ROI to be compelling.

Comment Re:Party like it's 1999 (Score 2, Insightful) 218

... we're just not there yet.

And we never will be unless someone bites the bullet and starts publishing 3D content. I have a feeling that the adoption curve for 3D television will be much quicker than that of HD television since the latter relied on scaling up the world's LCD production facilities.

Comment Re:Chain of evidence? (Score 1) 480

My apologies, that was meant to be an actual (non rhetorical) question. I'm curious about this issue. Can a third party accept consent to search on the government's behalf? Can the government require a company to require said consent in order to conduct its business? I'd be curious to see if there is any legal precedent on the matter. Related to the issue of "penetrative imaging" and the 4th amendment, an interesting bit of legal precedent is Kyllo v. United States. The supreme court found the use of thermal imaging without consent or a warrant to constitute an illegal search under the 4th amendment. Were the answers to either of the above questions to be "no," I'd imagine this case could be cited in challenging widespread use of these scanners?

Comment Chain of evidence? (Score 1) 480

This state-of-the-art technology cannot store, print, transmit or save the image. In fact, all machines are delivered to airports with these functions disabled...Each image is automatically deleted from the system after it is cleared by the remotely located security officer.

There are two interesting issues at play here. The first is obvious and of personal concern: privacy. The above, a statement issued by the TSA, is meant to alleviate concerns that the TSA employees will be swapping weird nudie photos of you, your spouse, or your children. There's a contradicting concern here. Ignoring the issue of whether or not the use of this device constitutes "search" under the 4th amendment, I assume they are using this machine to establish probable cause for an "actual" search? If so, the fact that images are not stored both opens the system up to the potential for abuse and fails to protect the TSA when they search someone who is a false positive.

Regarding the 4th amendment -- don't you have to consent to you and your property being searched before purchasing or checking into a flight? If that's the case then these machines are just a means for the TSA to carry out said search in a more efficient manor.

Regardless of the above, I don't like this one bit.

Comment Re:You damn well should (Score 1) 605

WTF? It IS a developer's job to worry about system security from an application implementation perspective. It IS a developer's job to understand the operating system well enough to understand the best way to use the operating system's APIs and services. It IS a developer's job to understand what software is on their system, because that software could be interacting with the program they are developing.

I'm one of the very few developers out there that has extensive experience in developing both high-level enterprise software and low-level embedded systems -- both hardware and software. I am constantly frustrated at the way people seem to assume the term "developers" represents some homogeneous group.

Your arguments make the assumption that the software being developed must interact with some desktop OS in some way. Not all developers are working on applications that are built for a target architecture that is the same as their workstation. Not all developers write software that must be concerned with a particular OS. These people are more concerned with things like motor drives, signal processing, etc. Many of them are highly competent at what they do, but don't give a damn about why you shouldn't disable a firewall on an insecure network -- that's somebody else's problem.

The answer to plover's question is easier said than done. A company that does any kind of development work needs an IT support department that is capable of understanding the needs of the developers and balancing those needs against those of the company as a whole. In some cases this will mean developers get local admin access, in others it will mean the opposite.

Comment Multidrop RS-485? (Score 2, Interesting) 635

If you're interested in embedded systems, a simple home sensor network would be a great project for getting started. It just so happens that RS-485 is a very simple serial interface to get working over existing phone cable. There are a number of (relatively) inexpensive off the shelf sensors that speak Modbus over RS-485 as well. Most of these sensors are for industrial control (SCADA) systems, but I'm sure you'd be able to find some interesting devices to play with in your home.

Good luck, and don't forget to disconnect your phone lines from the telco before playing with them!

Comment Re:I can't support this use of tax dollars (Score 1) 394

All that said, I'd really prefer to see private investors step up for factories and tax-dollars only used for public-domain research...

Can you comment a bit more on that? I genuinely feel like I might be missing something. My take is that if the government can make some sound investments, why not let it invest in private industry? Increased revenue is a good thing, is it not?

Of course, the key phrase is "sound investments." I don't think Uncle Sam needs to hire a crack team of Wall Street day traders, and I do think there needs to be a ton of legislative oversight on government investment in private industry (to prevent corruption and the like).

Comment Re:I can't support this use of tax dollars (Score 1) 394

There are tons of reasons for doing it the US. Off the top of my head I can think of (future) tax revenue, potential to increase US exports, and yes, actually -- jobs. In spite of the high degree of automation in factories, there is still a need for large numbers of skilled and unskilled workers in manufacturing.

Also, they're not talking about a factory for building products that have a bajillion years of process engineering behind them. Having the factory would give these companies feedback on new processes for making efficient batteries more efficiently.

Sure, a lot of people assemble products using these batteries overseas. However, if that were to change the US economy would see quite a boost. If this is a key component in making that change, I'm all for it. Not to mention that I'd love to see the US make some amazing new discoveries on these kinds of fronts, especially with the rules the GP mentioned.

Comment Re:Are actuators faster than direct connections? (Score 2, Interesting) 130

You're on the right track, but you're not quite there. Solar panels are more or less arrays of photodiodes. AFAIK most fiber system use PIN photodiodes to convert the light intensity over a specific band of wavelengths in a fiber to electrical current. Note that I said current, not voltage. Typically a transimpedance amplifier and some kind of comparator circuit is then used to measure the intensity of the signal. The PIN diodes can convert very small quantities of light to very small currents, and transimpedance amplifiers can deal with very small currents as well. Generally the limiting factor for low-light intensity systems like is the "dark current" of the diode you're using. If the current generated due to your light source is within the noise of the dark current you won't be able to detect any change in the system. Fiber systems operate at light intensities that generate currents well above this dark current, and they do so without a high power demand.

Power issues can be born from speed issues, though. Since photodiodes need a fairly large surface area to be able to generate enough current from light signals, the PN (or PIN) junctions act like a capacitor. Capacitors act like low-pass filters and this limits the switching frequency of the signal you can transmit. This effectively limits the data rate of the system. If you make the surface area smaller, you'll need to increase the intensity and focus of your light beam in order to make up for the change. This could cause high speed systems to have high bus power requirements and higher manufacturing costs.

Slashdot Top Deals

You have a tendency to feel you are superior to most computers.