Accelerometer sensor inside a car Does an accelerometer sensor measure the distance accurately when it is used inside a car? and what is the misjudge percentage when it is compared with its odometer?
Limits of dead reckoning using MEMS sensors I'm trying to track body parts relative to a person's torso. I see quite a few questions about using MEMS accelerometers and gyros for dead reckoning, and they confirm my suspicions that various factors greatly limit their usefulness for these sorts of applications, but I'm seeking clarification of these limits:   What exactly are these limits?  Other answers have addressed why these limits exist. Naturally the specifications the parts in the system in question and what is considered "acceptable error" for the system will both change the exact limits, but is there a single order of magnitude in time, or distance that I can expect dead reckoning to work? I'm well aware that over long distances (a few yards or so) the error becomes too large for most practical purposes, but what about within a few feet?  What can I do to improve these limits?  I'm currently looking at using an accelerometer and a gyro. What other sensors can I add to the system to improve the error rate? I know over longer distances a GPS can be used, but I doubt any consumer electronics grade GPS has fine enough resolution to help in my case.  Additionally, a general consensus seems to the only way to improve these limits past the point of improved sensors is to provide a reference not subject to error. Some systems solve this using cameras and markers.  What kind of reference points can a portable/wearable device provide?   I've seen the usage of radio waves to measure long distances accurately, but I can't tell if such a system could be accurate on such small scale (in terms of distance measured) using "off-the-shelf" components.
What would you call someone who makes no lasting impression? Suppose Alice publishes a book with a public key in it, and later wants to prove that she wrote the book. She could sign challenge messages with her private key, and others could verify those signed messages. Alice is proving she knows a private key without revealing anything about it.  Is this an example of an interactive zero knowledge proof?   Or does this example somehow not apply to zero knowledge proofs? Why won't my YN-568EXII work with a flash trigger? I have a Canon 5DMk2 and have just bought 2 Yongnuo YN568EXII speed lights. I have an existing Yongnuo RF-603CII trigger, but I cannot get them to work together! Does anyone have any suggestions, as the manual is no use :( Thanks Steve What are the dev-loop services that started on boot? After booting I ran systemd-analyze blame and here are the results:       21.596s systemd-journal-flush.service      18.658s dev-sda8.device      15.099s dev-loop33.device      15.034s dev-loop19.device      15.012s dev-loop34.device      14.989s dev-loop21.device      14.877s dev-loop15.device      14.866s dev-loop26.device      14.773s dev-loop27.device      14.684s dev-loop30.device      14.677s dev-loop32.device      14.649s dev-loop35.device      14.590s dev-loop25.device      14.267s dev-loop23.device      14.192s dev-loop24.device      14.156s dev-loop29.device      14.133s dev-loop16.device      14.065s dev-loop31.device      14.059s dev-loop28.device      13.821s dev-loop20.device      13.531s dev-loop22.device      13.495s dev-loop14.device      13.364s dev-loop18.device   What are these dev-loopxx.device (xx denotes numbers) services and why are they taking so much time? Are they related to the mounting of snaps? Can I reduce the boot time by disabling them? I'm running Ubuntu 18.04 alongside Windows 10. Why won't attribute modifiers add up on my armor? Why do bridge non-Captain officers commonly go on away missions? Ever since the days of Kirk, Spock, and McCoy, bridge officers in Starfleet have always had a prominent role in away team missions.  However, it would seem more logical to me that such hazardous (and, generally, specialized) duties should fall to lower-ranking and/or more dedicated teams.  Of course, it wouldn't have made for great TV if every away team was comprised of a bunch of red-shirts.  And it would definitely increase the show's budget to have an extra group of main characters whose sole purpose was to handle the away missions.  Still, I'm curious to know if there's ever been a real in-universe explanation for this practice?  I know it's been brought up a few times, in a few series/movies, that the Captain should not be taking part in hazardous away team missions.  But nothing is ever said (that I'm aware of) of the rest of the still valuable bridge crew or other senior officers. What are exchanges like "How are you," "I'm fine," and "See you later" called? How can I trick Minecraft into thinking two computers are on the same wifi network? Minecraft's got an "Open to LAN" feature, which can be used to set up a local server when two computers running Minecraft are on the same network. Some young relatives of mine use this to play together whenever they're in the same house, but they'd like to be able to play together from their respective residences.  A server is not optimal because it's a bit complex. I've tried using Tunngle to spoof that the computers are on the same connection to no avail.  How can I convince Minecraft's "Open to LAN" that their two separate computers are on the same network? I'm using OSX 10.9. I'm trying to set up Internet Sharing to connect my Android to my Mac directly over Wi-Fi. Every tutorial I've come across (including ) mentions checking a box for "AirPort" in a "To computers using" list. However, the option is simply not available on my machine:    I have a few related questions:   Why isn't the AirPort option available? Is there anything I can do to make it available? If there isn't, how can I work around it to finish setting up Internet Sharing so I can connect my Android and my Mac directly over Wi-Fi? How can I underline a single word with LaTeX? Given a simple paragraph, how do I underline a word in that paragraph?  (Note: I post this here because it wasn't really obvious using google or this site and my TexNicCenter is somehow missing this highlighting option.) Show/Hide  dropdown, with jQuery, based on value How can I assign a Func conditionally between lambdas using the conditional ternary operator? Generally, when using the conditional operator, here's the syntax:  int x = 6; int y = x == 6 ? 5 : 9;   Nothing fancy, pretty straight forward.  Now, let's try to use this when assigning a Lambda to a Func type. Let me explain:  Func&lt;Order, bool&gt; predicate = id == null     ? p =&gt; p.EmployeeID == null     : p =&gt; p.EmployeeID == id;   That's the same syntax, and should work? Right? For some reason that doesn't. The compiler gives this nice cryptic message:     Error  1   Type of conditional expression cannot be determined because there is no implicit conversion between 'lambda expression' and 'lambda expression'   I then went ahead and changed the syntax and this way it did work:  Func&lt;Order, bool&gt; predicate = id == null     ? predicate = p =&gt; p.EmployeeID == null     : predicate = p =&gt; p.EmployeeID == id;   I'm just curious as to why it doesn't work the first way?  (Side note: I ended up not needing this code, as I found out that when comparing an int value against null, you just use object.Equals) Problem aligning overlapping corner points in Illustrator I am drawing some overlapping paths in Illustrator. However, some anchor points of different paths do not align correctly, they create some rugged corners. I tried to manually adjust the points with the direct selection tool but it is difficult to handle the corners.  Can anyone help me to fix the corners in the red circles? How do you print the current month, day and year using awk and date? I can't seem to grab the month, day and year using   awk '{print $2, $3, $6}' date    Does anyone know how to? Default route lost on reboot Why can't I destroy or place blocks? If you open any of localized meta site in browser's private mode, e.g.  you will see untranslated text on the top right corner:        This message is not found in Transifex, hence unable to localize.  Related bug report on ruSO.meta: How do I install the Intel Graphics driver in my system? Can someone help me out and explain or point me in the right direction on how to check video drivers and see if my video card running okay?  I had 10.04 installed on my Thinkpad r61 with Compiz Manager and life was great, until the machine took water damage. I bought an ASUS (X54H) since and am trying out 12.04, but the desktop just doesn't look right.  I always struggled with video driver installation. There are no proprietary drivers available in the hardware manager.  When I run lspci | grep VGA:  00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)   I will greatly appreciate your help. I want to use Linux more, but like I said video drivers appear to be my biggest concern. I have also tried 12.04 on my desktop PC, but again failed to configure video card, so switched back to Windows 7. Handle application exit Algorithms for automatic model selection