Using jQuery animate on canvas objects

Question: I want to animate an html5 canvas element with just a simple shape drawn using the path mechanism.  When hovering a mouse over it I want to zoom in on it, make it more opaque and change the colors.  Can I do this with jQuery's animate() function?  What's the best approach?  Does canvas have a mechanism to do this kind of animation?
Answer: Unfortunately what you want to do would be very difficult using canvas (no longer the case - see UPDATE below) because once you draw a path on canvas it's just pixels so you can't just attach event handlers to it like with the DOM.
Fortunately you can do it if instead of canvas you use SVG because all of the shapes in SVG are DOM nodes just like divs and spans in HTML.
Unfortunately, SVG is not supported on IE.
Fortunately on IE you can use VML instead of SVG.
Unfortunately you can't use jQuery to animate SVG and VML objects easily.
Fortunately there's Raphaël, a JavaScript library with API heavily inspired by jQuery that does it all for you. It uses VML on IE and SVG on other bowsers. It works on Firefox 3.0+, Safari 3.0+, Chrome 5.0+, Opera 9.5+ and Internet Explorer 6.0+.
This is how you would make a red circle that would slowly change color to yellow on mouse over:
<code>// make a Raphael "paper" similarly to an HTML5 canvas:
var paper = Raphael(10, 10, 320, 240);

// make a circle on this paper:
var circle = paper.circle(100, 80, 20);

// change some attributes:
circle.attr({
    fill: 'red'
});

// register mouse enter and mouse leave event handlers:
circle.hover(
    function() {
        circle.animate({
            fill: 'yellow'
        }, 300);
    },
    function() {
        circle.animate({
            fill: 'red'
        }, 300);
    }
);
</code>
And that's it – see DEMO.
See this more complicated DEMO that makes a circle and on mouse hover does exactly what you asked about – zoom in on it, make it more opaque and change the colors.
See also this demo that I wrote for this answer about Raphaël.
UPDATE
When I originally posted this answer I wrote that what you are asking for would be very difficult to do using canvas because you would have to maintain some object hierarchy that is not present in canvas like it is in SVG or VML. It is still true but now there are libraries that can do the "very difficult" part for you, like for example
EaselJS,
KineticJS,
Paper.js or
Fabric.js and some others (see this comparison of canvas libraries maintained by the author of Fabric.js for more).
Comment: I'm confused: are we fortunate or unfortunate after all?
Comment: Fortunately, [SVG is supported](http://en.wikipedia.org/wiki/Scalable_Vector_Graphics) on IE9.
Comment: @Derek: unfortunately we still need to support IE 7 and 8 (6?) :)
Answer: well on this page google used some animated canvas icons.
http://www.google.com/chromeos/features.html
when you dig into code you'll see that they used JS Tweener. http://coderepos.org/share/wiki/JSTweener
i think its more reliable than raphaelJS if google chooses it ;). Canvas animation code is really complex though. i barely understand whats happening.

Using jQuery animate on canvas objects


Mud type for sticking paper tape

Question: When you lay the paper tape over a drywall seam, does it make any difference whether the mud you filled the gap/crack under it is hot 20/45 or regular joint compound that comes ready in buckets and takes a day to dry? Also, is it recommended to first fill the crack and wait for it to dry before applying another coat to just serve as adhesive for the tape or can it be done all in one step, meaning apply the tape over a thick (and possibly mushy) layer of mud?
Comment: Yes, setting compound = hot mud.
Comment: USG says either hot or premixed for paper tape. (But setting type for mesh.) https://www.usg.com/content/dam/USG_Marketing_Communications/united_states/product_promotional_materials/finished_assets/matching-joint-compound-with-proper-joint-tape-white-paper-en-usa-J2140.pdf
Comment: Drywallers will probably have their opinions on the best, but we just used the bucket type.  Depending on the size of seam you usually want thinner than thick mud layers.  Feather it out more than trying to save mud to a narrow strip.
Comment: There's an ASTM for drywall finishing. C840. For seams wider than 1/8" it requires setting type mud. There's "shall" language asserting that thou shalt not apply a finishing layer over another wet finishing layer, but nothing about putting an initial finishing layer over wet tape. I would expect the tape plus finishing layer to shrink a lot.
Comment: @AloysiusDefenestrate is setting type the hot mud?
Answer: It is always best to fill any gaps first before applying the tape. This helps the paper to lay flat. Filling the gaps is best completed with hot mud as it will shrink less than regular mud.
Now, it comes down to preference, skill, and available time:
If it is a small scope, or if I'm short on time, I will proceed to tape with hot mud, though with a wetter mix than when filling gaps.
Once tapping is done, I can apply the first coat over the tape. Again, if it's a small scope or I'm short on time, I will do this first coat with hot mud. If I'm almost done for the day, or if it's a larger scope and I don't want to keep mixing up hot mud, I will use regular mud and let it dry overnight.
There are differences between the muds. Hot mud provides a harder finish when dry, which can be beneficial in some locations, but it will also take a little bit more effort to sand if not applied smoothly. Obviously you also have a reduced amount of time to work with it.
General-purpose mud and taping mud can be used for tapping (general-purpose can be used for all steps). Taping mud tends to have more adhesion. However, you can add white glue to your mud for more adhesion if needed
Finishing mud should not be used for tapping.
A great youtube channel for more information and advise is Vancouver Carpenter.

Mud type for sticking paper tape


How shall we prove electric field is negative gradient of potential in case of an arbitrary charge distribution?

Question: In schools we learn about electric field of point charge being negative gradient of potential. From this how can we generalize it for charge distributions? Any proof will be appreciated.
Comment: About the negative: that is just a convention, we notice that in electrostatic $rot \bf{E} = 0$ and from that we deduce that the electrostatic field derive from a potential, we usually write it $\bf{E}=-\nabla \phi$ but nobody prevent me from defining $f=-\phi$ and from that writing   $\bf{E}= \nabla $$f$calling $f$ the potential
Answer: Thanks to the principle of superposition: you can imagine an arbitrary charge distribution as the superposition of infinitesimal point charges.
$$
\rho (\textbf{x}) = \sum dq_i\, \delta(\textbf{x} - \textbf{x}_i)
$$ Therefore the potential of the distribution is the sum (possibly the integral) of the potentials due to every single charge:
$$
V(\textbf{x}) = \sum V_i(\textbf{x}) \,\,\,\left(= \frac1{4\pi\epsilon_0}\int\frac{\rho(\textbf{x}')}{|\textbf{x} - \textbf{x}'|} d^3x'\right)
$$
 Since the sum of the gradient is the gradient of the sum,
$$
\textbf{E(x)} = \sum \textbf{E}_i(\textbf{x}) = \sum \left( - \nabla V_i(\textbf{x}) \right) = - \nabla \left(\sum V_i(\textbf{x})\right) = - \nabla V(\textbf{x})
$$
 you have shown that the electric field of a charge ditribution is the negative gradient of its potential.


Tips for creating a pumpkin texture

Question: I used the video tutorial by Ryan King to make a pumpkin model and just learned some pretty cool ways to make the pumpkin texture by using nodes, but I don't know many of the nodes and what they can do, so I'm just wondering what nodes I could use to make this type of pumpkin below.
Comment: pretty much the same set of nodes, but with different colors and settings.  Experiment with the material and see what happens.
Answer: Maybe to start, try somethings like this. A Wave Texture provides the vertical lines, and a Noise Texture provides the "speckles". Make sure to use UV texture coordinates, otherwise the lines will only cross one axis and won't "wrap around" the sphere nicely.
I used the Noise Texture as a basis for a small Vector Warp of the input Vector to the Wave Texture which makes the lines more fuzzy/random. This plus a small amount of distortion on the Wave Texture itself makes the vertical lines more realistic (less linear and fake looking).
I used the Wave Texture as a basis for a bit of a Bump, but not the Noise. This is just a personal choice, and you can use them both if you wish, just make sure the speckles are "softer" than the waves when mixed.
Speaking of softening, you can see in several instances, I mixed the value going into an input socket (quite heavily) with white first. This is because procedurally generated values are often too "strong" (gives weird effects), and lowering the contrast first often makes things better. I use the MixRGB with white because the slider gives good, precise control.
This isn't the end result, but is should go a good way towards getting you started. Let me know if you have any questions ;)
Comment: It is *Vector Math* @AlexWillis21
Comment: What is that purple node that is called add. I can't find that when I search it. Is it a separate node I have to install to get?
Answer: Recommend putting on a couple layers of distortion to get the colors broken up with spots of different sizes.

Tips for creating a pumpkin texture


the more the merrier - definite article used as an Adverb?

Question: The grammar book says:

1) "The" is used as an adverb in such sentences; as,

The more the merrier.
The fewer the better.

I tried google bt it is not helping me. so I came here.
Comment: What exactly is your question?
Answer: "the + comparative" is not the normal article (nominative/accusative), but an old fifth case form of "that" which was comparable to the Latin ablative.

the better, the more expensive

Here was the underlying idea: in that measure something is better, in that same measure something is more expensive. That was parallel to the way how in Latin the idea of proportionality was expressed.
This old case form changed its shape and got the same form as the normal article. Dictionaries label this form of the article as adverb which is somehow justified, but one should know the story behind "the + comparative". And perhaps it would be better to label "the" as particle or function word.
AHD, American Heritage Dictionary:
[Middle English, from Old English thy:, the:,  instrumental of thæt, neuter demonstrative pron
(: means long vowel)
See AHD, the no.2, adverb
https://www.ahdictionary.com/word/search.html?q=the&submit.x=52&submit.y=37
Answer: SUPPLEMENTAL to rogermue's ANSWER
Pay no attention to the adverb designation. This is a 'fixed' comparative usage, whose origin rogermue describes. Dictionaries have to call it something, and "adverb" is the wastebasket term where uses that don't fit into any other category get put.
Answer: Over the last 30-40 years, linguistic terminology has changed. If a word expressed manner or degree, it used to be considered "adverbial". The term adverb is slowly being supplanted by new terms: adposition, preposition,  postposition, interposition, and circumposition.
This form, the X the Y, means "Y is in proportion to X". The proportion can be direct or inverse.
The slower you walk, the longer it will take to get there.
The faster you paint, the more likely you are to make a mess.
The more, the merrier!
(The more people at the party, or in the party, the more fun it will be.)
Comment: While "the more likely you are to make a mess" is undoubtedly an example of predication with "more likely" being a predicative adjective to "you," it is unclear whether a predicative relation holds between "longer" and "take."
Answer: I don't think those are very good examples, since technically they're not complete sentences, but more of phrases or "sayings". This would be the expanded version of the saying:

The more (something, typically people there are) the merrier (it will be).

Neither "more" nor "merrier" are verbs here, the subjects and verbs are actually missing from the original phrase (I've included them in parenthesis). "The" is not functioning as an adverb in this phrase or sentence.
I've done some basic searching myself and I cannot think of an example where "the" would function as an adverb.

The fox frantically sprints across the meadow.

Frantically is the adverb here, and replacing it with "the" would obviously make no sense. The whole premise of an adverb is that you're trying to be more descriptive about the action, the verb itself. Even if you were able to find a way to tack on an article like "the" to a verb, I don't know why you would do this, as it wouldn't add anything.
Answer: According to M-W:

1:  than before :  than otherwise —used before a comparative [none the wiser for attending]
2a :  to what extent [the sooner the better]
2b :  to that extent [the sooner the better]
3:  beyond all others

According to Dictionary.com:

(used to modify an adjective or adverb in the comparative degree and to signify "in or by that," "on that account," "in or by so much," or "in some or any degree"):
  He's been on vacation and looks the better for it.
(used in correlative constructions to modify an adjective or adverb in the comparative degree, in one instance with relative force and in the other with demonstrative force, and signifying "by how much … by so much" or "in what degree … in that degree"):
  the more the merrier; The bigger they are, the harder they fall.
Comment: Note: This is a dictionary answer. Typically, questions that are resolved with a dictionary answer are discouraged.


Mail Server using Postfix

Question: I have currently set up my web application on Amazon EC2 server. As a well known fact sending email from EC2 has a problem. As a cheap and long lasting solution instead of using "authsmtp" is it possible to rent a server and use it as a Mail Server? I am currently looking for cheap hosting which will give me root access so that it can be configured and used as a relayhost. I am curently using Postfix as MTA. Has any one implemented this before? I am curious about its feasibility of this solution. I guess common requirements are: 1: Dedicated IP which is not black listed. 2: Open relay( open to my Server only) Any Tips for Header configurations to keep the mails out of spam folder. This is like exactly cloning authsmtp for personal use. Any suggestions for other Mail Server software instead of Postfix? Another problem is Reverse DNS for this server. Should PTR entry be present if a server is used as a relayhost?
Answer:
is it possible to rent a server and use it as a Mail Server

Definitely, this is the solution my company implements. If you're not too worried about the time it takes to open an SMTP connection, you could use any free (gmail) account to send your mail too - you'll still need DNS config, and it's slow, but you'll get the mail sent as if it were despatched from the account itself.
I have recently answered some of these points. In summary, for config and prevention of "spam" tagging:

You can check blacklists here
Your server must have MX and reverse DNS records
You must always have SPF DNS records (many servers reject mail without a valid SPF, GMail for example, here's an explanation and a wizard)
For general config, your mailserver's HELO response must match your hostname
Your mailserver is not an open relay - it must be a "closed" relay dedicated to your server - see how here
Finally, ensure your DNS records' TTL is not too low - 86400 (24 hours) is recommended (some spammers set their TTL very low to regularly update forged DNS records)

Any suggestions for other Mail Server software instead of Postfix?

Not unless you use a remote SMTP server from your code, and this is slow. Qmail is the only real linux alternative: it's slow, cumbersome and irregularly updated. I wouldn't recommend it.

Another problem is Reverse DNS for this server. Should PTR entry be present if a server is used as a relayhost?

I believe DNS records (including reverse records) are always required: there are many different providers who check slightly varying parameters, so be sure to verify your configuration on every major provider (if possible!)
Comment: Thanks Andy. Can you suggest some Hosting services? Possibly cheap and can be configured as relayhosts for Mail.
Comment: The only hosting company I have ever been happy with is Rackspace, however they are not cheap :) Otherwise anybody who will host a linux box would do, although it's worth notifying them of your intentions beforehand.
Answer: You're probably better off paying someone to do that hosting for you.  You don't want to do all the work to keep a mail server running, and it sounds like you'd take quite a while to get started on it.  Outsource the stuff that you don't care about :)
That being said, yes you could do that.  Mattering on load, you could probably go with a VPS running whatever distro you're comfortable with.  Postfix isn't too bad to set up, and configuring it to accept mail from a set IP (your EC2 instance) wouldn't be hard at all.
You could also configure authentication there, and set up a mail server on your EC2 instance which relays through your mail server and knows how to authenticate.  That way if you need to change IPs on your EC2 (I don't know if you get allocated one or if it can change) you won't have to mess with the mail server.
Comment: For a quick overview of possible vendors, there's a chart here: ( http://tomuse.com/vps-virtual-private-server-web-site-hosting-compare.html )  Before you pick one, it would be a good idea to do a quick check through the Spam-L mailing list archives to make sure they don't have a reputation as a spam-friendly hosting service, otherwise you'll likely run into blacklisting issues
Answer: Any virtual dedicated server would do this fine.  You just go to a company like slicehost, order a basic one, choose your preferred OS for it, and it'll be ready in no time.  Log in, setup your mailserver, configure firewall etc., and you're done.
Comment: @Lee B: If you have past experience in this domain, then it's probably easy for you. And you're right about the capacity issue, any VPS should be fine for a few thousand emails per day. I don't like to see the task almost trivialized though... Mail deliverabilty is an ongoing arms race between spammers and the countermeasures that ISPs take, and companies who need to send legitimate email can become unintended victims. Additionally there is an upkeep to keeping a Internet server secure, both in terms of installing security updates, and periodic maintenance. There is work in the DYI approach...
Comment: Yes, but I'd expected that you know all that, and you've confirmed it here, so I didn't mention it.  If there's anything else you're unsure of, ask the question, but it would be silly of me (and patronising) to spell it all out if you likely don't need to know :)
Comment: p.s.: I'd definitely recommend postfix.  It's the nicest mail server I've used from an administator's perspective, and is often held up as an example of great coding/software design, too.
Comment: Thanks for the suggestion Lee. This is a serious problem with EC2. I hope they do something to improve upon it. Moreover we end up spending about 100$ a month for an instance and need to spend some more just for the mail server.Apart from that the resources spent in configuring it and testing it.Most solutions I got were suggesting using relayhost like authsmtp so I was wondering if this would work.
Answer: You could also Google down a few smarthost providers and subscribe to their service to send out email.
The EC2 issue isn't the headers, it's the source IP.
Answer: It could be caused by the previous owner of that IP address ..
Get to know the allocated IP address and check it againts RBL and check the IP address reputiation againts senderbase
http://www.senderbase.org/
http://www.dnswatch.info/dns/rbl-lookup
Another tips is to set your Reverse DNS entry for the IP address and match with the forward
entry. Setting up  SPF / DKIM entry for your domain also help as more and more people adopting SPF.
If you are sending a lot of email the deadbeats ticks :
Postfix Stagger/Rate Limit Outbound Mail
Answer: You may want to look into a VPS solution for your mail server needs. There are many available, most are likely inexpensive. I've used VPSLink (http://vpslink.com) for a few years for both private and commercial products, and have had mostly good experiences. At this time, their lowest offering will get you a barebones VPS for about eight US dollars per month.
Some caveats I've run into on a VPS solution:

It won't run java (at least, not on OpenVZ). There may be solutions for this.
It will likely not have a usable MAC address. This could affect any software that generates UUIDs, though there are proscribed ways around this (see RFC 4122 for more details).
Answer: You can have Amazon setup a PTR for your EIP. This is the form to use for that.
http://aws.amazon.com/contact-us/ec2-email-limit-request/
Answer: You could go to all this trouble setting up and maintaining your own Postfix server, and that might be the way to go if you want mail services other than just sending out on behalf of your web servers.  However, it'll be cheaper and easier to just have somebody else do it.
SendGrid Basic compares pricewise to a fairly cheap VPS host, but will be a lot more stable and has more features you don't need to maintain yourself.  If you're sending out a lot more emails than that, the features of Silver and above will be worth your while.
If you're particularly cheap then I've seen people create a Gmail account and use the Google smtp servers from their web apps.  I wouldn't like to comment on how sensible that is, but it seems to work for them.

Mail Server using Postfix


Need bin or hex file for Pic 16F648A Serial LCD

Question: I have seen some kits and boards for a Serial LCD based on the PIC16F648A.
A have a few of the chips and a few LCDs. I'm not into PIC programming, does anyone have a link to the compiled software I can program my PIC chips with to make my own serial LCD?
Comment: How do you plan to feed data into your pic? This question is difficult to answer without knowing that.
Comment: Which LCD do you have? (Is it SPI, I2C, other?) And are you sure you want the *compiled* software? Kinda useless, as such.
Comment: I planned to send serial data like in the Sparkfun SerLCD_V2 spec. I don't know the brand of the LCD, it is a 4 x 20 with the parallel 16 pin header HD44780 type controller. I have it working on Arduino using the liquidcrystal library, but wanted to mount it remotely, since I had some 16f648 chips laying around, thought that would work. Thanks for your input.
Answer: Compiled bin/hex files are very specific and can not be easily adapted to your specific situation. This means that the bin/hex file would have to be for the exact PIC you have along with all of the exact pins connected as was designed for in the original code.
Also many companies protect their code and compiled versions of their code very tightly. This means that there is a good chance that they wont just hand it over to you.
So, likely you wont find an answer to your question. Instead you should look to see if someone has released information on how to build what you are looking for. It will require that you are willing to be open to learning about firmware coding as you will have to touch it to work on a project like this.
Comment: Thanks kellenjb - that explains why I had no luck in finding any. Would have only wanted open source if available. I'll dig in.


Web Deploy create Virtual directory and add application

Question: I need to deploy web applications to an IIS 7.5. I have tried to create a web deploy package but I run into a problem.
Most of the applications I need to deploy are nested under virtual directories. Example:
Web Site/vDir/vDir/application

This seems to work if the virtual directories are already created. But if they are missing the application are instead created directly under the Website.
I create the package with the parameters /t:build;Package
Atm. I am using the cmd file to deploy with parameters /Y /m:[Servername]
I can't find a way to change the dest parameter. Do I need to use msdeploy directly instead?
Answer: I saw a very similar question containing a good answer by AaronS.
He basically suggests creating a custom build task, including an example code.


Get a message or notification when new mail form is opened?

Question: I need an event/message/notification in an outlook addin, which fires when a new mail form is open by an user? I don't know how to determine which window is opened.
Answer: You can make use of Inspectors.newInspector event which is raised when you open any outlook item in a new window. In the event handlerfor this event, you can check if the Inspector.CurrentItem type is Outlook mail and mail item has isSent as false that means it is an outlook mail item in edit/compose mode.


Constituent borders

Question: Let us imagine there to exist, for instance, a DP. We always observe the only head D on the left or the right of the phrase (depending upon the direction of branching). But every constituent naturally have two borders which we normally indicate by brackets. Why aren't they detected? If they were expressed morphologically as heads and terminators how should we mark them in drawing the tree? As being category-markers, they would pertain to the same category thus causing us to assume the existence of discontinuous morphems (instances of the head), right? If so, how should we draw it?
Answer: In Syntactic Structures, Chomsky remarked that natural language needs a grammar more powerful than regular grammar (type 3), such as context free phrase structure (type 2), in order to keep track of the pairing of such phrase introducers as "if" and the corresponding "then" clauses which go with them.
I don't recall C's exact example, but consider the language generated by this context free phrase structure grammar:
<code> S -> it rains
 S -> if S then S
 S -> {john, mary} leaves
</code>
which pairs up each "if" with the correct following "then" ("correct", because in the tree structure, the "if" and corresponding "then" are in the same S).  E.g. "if it rains then john leaves", "if if mary leaves then it rains then john leaves", "if if if it rains then it rains then mary leaves then john leaves".
There is, of course, an obvious problem with the facts of English, here.

Constituent borders


Rating a candlestick between a range of bullish to bearish

Question: Is there a method to rate a candlestick on a score of bearish to bullish maybe like on a range of 0 to 100? like a bullish marubozu would get a 90-100 whereas a bearish one would get a 0-10 and doji might get something in range of 45-55 and all other candlestick types might be judged on this scale too?
Answer: The effectiveness of candlesticks is relative to what has been going on in price just before the particular candlestick came about.
For example, if you got a doji in a flat sideways market it would be meaningless, as a doji represents indecision and the market is already in indecision (going sideways). But a doji or series of consecutive dojis at the top of an uptrend or bottom of a downtrend, can be an indication that the price may change direction.
So you really need to have an overall view of current price action to determine how effective a particular candlestick might be.
You can't really give an individual candlestick a rating, it much depends on its relativity to the rest of the price action. But what you might be able to do is come up with your own rating system based on the psychology of the particular candlestick and the preceding price action before it, and then only take a trade if the score is above say 8 out of 10.
For example, if your doji occurs after sideways action you might give it a 0, if it occurs after a steep trend you might give it a 5, if you have several consecutive dojis after a steep trend you might add one point for each additional doji, and if you notice that in the past every time there is a doji straight after a steep trend the price reverses say 70% of the time, you might add another 2 point.
So you need to look at the whole picture to try and increase your odds, not just the candlestick by itself.


How Admin can logout other users?

Question: The users can logout visinting my-site.com/logout by themselves
But is there any way Admin can logout other users?
Answer: If you go to admin/user/user, you can block the user, which will cause them to be logged out.  After that, if you want them to be able to login again, you can just immediately unblock them.  Also, if you as an admin change a user's password, they will be logged out and will have to use this new password to log back in.
If you want to get fancy, you could do something like this in a custom module as well:
function YOURMODULE_user_operations($form_state = array()) {

  $operations = array(
    'logout' => array(
      'label' => t('Logout the selected users'),
      'callback' => 'YOURMODULE_user_operations_logout',
    ),
  );

  return $operations;

}

function YOURMODULE_user_operations_logout($accounts) {
  foreach ($accounts as $uid) {
    sess_destroy_uid($uid);
  }
}

which would add a "Logout the selected users" option to that menu as well.
Comment: I love learning about hooks I have never used.  What a simple solution to a common problem.
Comment: quite welcome, I added some quick off the cuff fanciness to the answer as well.
Comment: Two quick notes about this.  `sess_destroy_uid` is for Drupal 6.  Use `drupal_session_destroy_uid` for Drupal 7.  This won't work with Administration Views in Drupal 7 (haven't tested 6), which use VBO.  VBO removed hook_user_operations, so you have to use an action instead.

How Admin can logout other users?


A Timeless God and His Will to Create: Contradiction?

Question: Many God believers say, God is timeless, or atemporal, he exists outside spacetime. Where there is no time, there is no change. But in order to create the Universe, God would have to have an impulse, the will to create it. However this and the very act of creating is a change. Yet, God is atemporal. Isn't that a contradiction?
Comment: Where do you get that many believers say God is atemporal? From [here](http://www.iep.utm.edu/god-time/): "Now, the dominant view among philosophers is that God is temporal. His eternal nature is thought of as being everlasting rather than timeless." Following your reasoning every believer must believe God doesn't do anything, since doing something is change. But then prayer loses the aspect of supplication entirely - surely that is not in line with what many believers say?
Comment: temporal or atemporal?  or eternal?  unchanging?  existing within or without spacetime?  perhaps, but we dunno much about God.  and we understand even less.  we can speculate, though.  no harm in that if it doesn't lead us into nasty positions where we enforce our speculation upon others.
Comment: Is it necessarily true that change only occurs over time, and that where there is no time there is no change ? Isn't that just a human view of things ?
Comment: I see existence as intrinsically temporal. Is an electron that exists for exactly zero seconds any different from a non-existent electron? If one wants to posit the possibility of some kind of timeless existence that's fine, but this concept strikes me as so radically different from ordinary existence that it would probably be easier to invent a new word for it altogether.
Comment: Potency is timeless. God might be a potency. And creation as the will of god maybe equal to "actualizing potential". Actualizing potential requires time, but that doesn't mean potency requires time to exist. Potency just is.
Comment: @Keelan - The same article clearly indicates that atemporality was a dominant theological belief for many centuries.  Regardless of what may be current among philosophers (and in the intro, the same article is less confident), I don't think the OP is making any great stretch to say that "many believers say God is atemporal."
Comment: Besides the problem of being timeless, an omnipotent and timeless God needs no intelligence : if he is omnipotent then he can randomly cause all possible events at the same time (which is no time for him) ... which poses a question : why would this being need intelligence if he can throw all random dice at once, resulting in all possible configurations of Universes? (being omnipotent, means that for this being : throwing one die is as easy as throwing an infinite number).
Answer: I cannot speak for every system of belief in God, but here is one way I've been taught to resolve the problem you observe.
God being perfect cannot experience change, and so cannot experience a change in his will that would have created the universe "at an impulse." It is better instead, to say, while God is eternal, he is also a single Devine Act (identical to the act of being from Aquinas). He is, as many have drawn the analogy, the Author of a great work, who is not absent from the story nor bound by the same passage of time as the book.
As an example, one of the main creeds of Christianity discusses the precise idea of "verbs happening" before creation began. The Nicene Creed mentions that the Second Person of the Trinity "was born of the Father before all ages... was begotten not made," and that the Holy Spirit proceeded either from the Father or the Father and Son (depending on which branch). Since these things happened before "all ages," they proceeded time, and so it's not accurate (in this point of view) to think of them simply having happened in some time before Creation.
It is also a common refrain among Christian philosophers that God had no need of creation, so again, it is inaccurate to speak of an "impulse" causing God to create the universe.
Answer: Yes it is a contradiction. The Advaita philosophy says that the question can only be asked in the realm of causation; it cannot be asked or answered outside the realm of causation. In the realm of the atemporal God (the Absolute or Nirguna Brahman) there is no why, there is no cause and effect. An illusion can only be seen within the illusion, outside an illusion there is no illusion perceived. Swami Vivekananda says (Complete Works, V2, section Jnana Yoga, lecture The Absolute and Manifestation; available here - http://cwsv.belurmath.org/volume_2/vol_2_frame.htm):

What you call motion and causation cannot exist where there is only One. We have to understand this, and impress it on our minds, that what we call causation begins after, if we may be permitted to say so, the degeneration of the Absolute into the phenomenal, and not before; that our will, our desire and all these things always come after that.

And further:

But first we have to understand this that the very asking of the question "why" presupposes that everything round us has been preceded by certain things and will be succeeded by certain other things. The other belief involved in this question is that nothing in the universe is independent, that everything is acted upon by something outside itself. Interdependence is the law of the whole universe. In asking what caused the Absolute, what an error we are making! To ask this question we have to suppose that the Absolute also is bound by something, that It is dependent on something; and in making this supposition, we drag the Absolute down to the level of the universe. For in the Absolute there is neither time, space, nor causation; It is all one. That which exists by itself alone cannot have any cause. That which is free cannot have any cause; else it would not be free, but bound. That which has relativity cannot be free. Thus we see the very question, why the Infinite became the finite, is an impossible one, for it is self-contradictory. Coming from subtleties to the logic of our common plane, to common sense, we can see this from another side, when we seek to know how the Absolute has become the relative. Supposing we knew the answer, would the Absolute remain the Absolute? It would have become relative. What is meant by knowledge in our common-sense idea? It is only something that has become limited by our mind, that we know, and when it is beyond our mind, it is not knowledge. Now if the Absolute becomes limited by the mind, It is no more Absolute; It has become finite. Everything limited by the mind becomes finite. Therefore to know the Absolute is again a contradiction in terms. That is why this question has never been answered, because if it were answered, there would no more be an Absolute. A God known is no more God; He has become finite like one of us. He cannot be known He is always he Unknowable One.

We exist within the realm of causality, all of our perceptions and reasoning are dependent upon this. The question can only be asked within this realm.
Answer: Once we step out of the spacetime context we can no longer apply any reason from within the spacetime context ( impulse, temporal ) to the problem so we can't conclude any contradictions.
This doesn't mean there isn't a contradiction. There might be. Also such a question simply might be non nonsensical because it assumes the existence of something that may not exist (I'm talking more about things that exist outside spacetime than I'm talking about a god, though not saying god exists either).
Comment: I don't think that quite follows at least on the majority views about logic. Modus ponens for instance doesn't require a temporal gap between, (1) A -> B and (2) A. It just requires the two claims. / i.e., We can distinguish logical consequence and sequence from temporal consequence and sequence. In fact, one issue with first-order logic is that it is not tensed but the world we live in seems to be tensed (future/present/past).
Comment: but the problem is, we can't make those claims. simply saying god created the universe has no knowable meaning.  Then saying there must be an impulse, that too is not knowable.  Then claiming that is a temporal activity is also not knowable, then claiming its a contradiction is all based on non knowable things is not logical.   If you can make claims that have some kind of knowable meaning, then sure, logic will apply.
Comment: I think I partially misread your first sentence then. My hang up is with the use of "any reason." Do you mean as temporal beings we can  have no capacity to engage in reason that is atemporal? (kind of a quasi-Kantian claim).
Answer:
Many God believers say, God is timeless, or atemporal, he exists outside spacetime

Otherwise he would be part of creation; or he would be creating himself.

Where there is no time, there is no change.

This might be debatable; Aristotle for example said that change was an aspect of time; and then suggested that change was motion.
Following on from this, Mach suggested that time was exactly motion; and specifically the motion of all the background stars - the stars in the far distance; essentially everything else except us.
Einstein tried to incorporate this into his theory of time (ie Relativity) but failed; however Julian Barbour recently found a way of making this quantitively explicit.

But in order to create the Universe, God would have to have an impulse, the will to create it. However this and the very act of creating is a change. Yet, God is atemporal. Isn't that a contradiction?

Not really; its the act of creation which is atemporal. Change is motion and temporal; ie within creation.
Answer: No, there is no contradiction!  However, since you make several statements, I will address/answered each one separately.
1) God is timeless - this is true because, although God is multi-dimensional, time is not one of His dimensions.
2) He exists outside spacetime - this is "sort of" true, but it would be more accurate to say that spacetime exist "inside" God.
3) Where there is no time, there is no change - this is not true! Movement/change in four-dimensional space, does not require time!
4) In order to create the Universe, God would have to have an impulse, the will to create it.  This, and the very act of creating, is change - whether God has an "impulse" or not, and whether He acts or not, makes no difference because whatever He does, takes Him no time to do it (per responses 1 & 3)!
In conclusion, there is no contradiction because "time" is not applicable to God.
Comment: `does not require time!` I wouldn't be so sure. Maybe not the time that we experience. But when information is processed (change is a result of information being processed) you have to have time in some layer that is processing the information. When your computer alters the position of the player of a 3D movie (being a 4D change) it takes a certain amount of time doing so. When you as a player **inside** a game (>5D) are getting reset to a checkpoint, it takes no `player-time`, yet the computer requires time to make the change, but you, as the immersed player, wouldn't notice it.
Answer: Maybe gods will is more of a logical thing than a choice of some being. Much like the algorithm of a fractal. A fractal can only grow (or come into existence) when energy is applied to the right formula. Time is not required for the fractal algorithm to exist, in potency it exists without time. So in potency the whole fractal up to endless iterations already exists, without time. But in order to create the 1024th iteration, to bring it in to existence, you have to have time, because energy needs to be put in to do the calculations.
We people tend to anthropomorphize god. But maybe god is just "the right thing" that allows creation. Just like a fractal algorithm allows you to create endlessly. You can't be calculating a fractal and suddenly change the algorithm and expect to be still creating an endless pattern. You might be well ending up in a pattern with a dead end if you do.
In my view, gods will equals fractal logic. It is the only way to keep creating.
In that sence, yes gods will is timeless, and its will to create isn't a contradiction with being timeless.
EDIT:
In addition to creationism vs evolution: I believe we are part of both. Initially we were created and 'let loose' to evolve. Much like a programmer can create artificial self learning intelligence. It is created, yet it evolves. And where is the beginning in that? There is none, I believe its a fractal pattern with no beginning nor end :)
Answer: I like to answer such question not with the bibel but just with reasoning.
1st: I think we can't understand god itself. So we don't know if our description of dimensions and our picture of everything is right. I like to think more about god as a thing existing in everything. This is my definition of not picturing him. So saying he created something is maybe not quite complete. I think he is part of our world too and he is here. So it is not like building a lego tower, it's more like forming and changing things in a ordinary manner. So with respect to our world maybe more like making a stop motion movie about a part of your own. I think the laws of nature can be as well described as god. They are not predictable and our understanding is and will be forever incomplete.
2nd: Another though which is similar to the first one; for god our world is like for us a painted image. He sees everything, the space and the time at once. Maybe his interest are more about varying things like a painter would redraw a part of his painting. So it's not unreasonable if he sees everything at once that he would create things. He just creates thing in a way we don't understand which changes in our whole timeline simultanious, so we would not even now that he changes something because for us it would be just a natural thing which we remember of our childhood. So god has not the same time as we have.
P.S: My favorite definition of god is as a thing which is everywhere and something we can't measure. It's actually really about not making a picture of god. For me the answer if god exists or not doesn't matter anymore. The more important thing above religion are more the ethics which have every religion in common, be kind to people, treat the other like you want to be treaten and all this messages. I think religious fights are the real contradiction.
Comment: Given the definition of god in "1st", I'm confused as to how such a god would have a will or create as you suggest in "2nd".
Comment: In 1st I said god is everywhere and exists in everything. In 2nd I said maybe he forms our world like a painting. So long story short: god can do whatever he wants. He can changes things in every point in time and space. Maybe confusing is that I don't think god is an old man coming down and move things. I picture him really in everything. I hope this makes it clearer, sometimes it's hard to say difficult things in an easy manner, just say if something else isn't quite clear.
Comment: If god is a part of the world, how can he create? Wouldn't that be thoroughly circular?
Comment: Transforming Energy into mass -> create something. You can also watch it as transforming sth. Also if god exists I am not sure if he has to obey laws of nature...
Comment: But if God is both the energy and the mass ... then how does that entail God creating something? Then isn't God just reshaping?
Comment: Yes you can say he is reshaping. It depends on the point of view. You can either say he creates something if you don't know if this energy has existed before or you can say he is reshaping. The difference here is only the source of the energy. I said creating because it seems to be more topic, but I think from what we can know about god it doesn't matter


How can I notate this better in 12/8 time?

Question: Can I write tied notes instead of half notes? tied dotted quarter + an eighth note? If not how can I write this better?
Answer: 12/8 is essentially 4 lots of 3 quavers, and needs to be written out in that pattern. True, the sum total for one bar is 12 quavers, or 6 crotchets, if you like, but it represents compound, not simple time, as 4/4 is.
As it stands, assuming that's one whole bar, then you have the equivalent total note value, but in 12/8, it isn't written thus.
With nothing else to go on, the time signature for what's there could easily be 3/2. But perhaps you mean 'how can I write 3 equal notes in a bar of 12/8?' Then, you could simply make them three triplets, which most readers would understand.
Answer: A is 'correct'.  B is quite acceptable in modern usage.    C is another option.
Answer: As with any notation, you want to make clear where the main beats begin. In your example, it's unclear where beats 2, 3, and 4 are; they're somewhere hidden in the middle of each of those notes.
As you've guessed, you'll need to clarify this with ties and note values other than half notes. Consider the notation below:

This notation clearly shows where beats 2, 3, and 4 are by giving them each their own dedicated notehead. (You don't need to have the "2", "3", and "4" above the staff; that's just for explanatory purposes.) By showing where these beats lie, you help guide your performers through the measure.
I should, however, show one other possibility, albeit a much less commonly used one. If the tempo is fast enough (so that the 12/8 really occurs in 2 as opposed to 4), it could be helpful to clarify them as triplets:

But this is best saved for only certain occasions. If the tempo is such that the 12/8 is felt in four, then most musicians would perform the above example far more accurately than they would this one.
Comment: I've always felt that tuplet notation, while very useful, uses the wrong number. I don't need to be told how many notes (or, strictly, beats) are included — that's obvious at a glance! What I need to know is how much time to stretch/squash them into, and that's _not_ so obvious…
Comment: @AndyBonner If the 3-for-2 were notated with crotchets/quarters, then the result would occupy only 2 of them, i.e. only a third of the 12/8 bar. Even the example in this answer makes no sense to me — it gives 3 minims/halfs, which would normally take 12 quavers/eighths, and squeezes them so that they occupy… 12 quavers/eights! To use the normal triplet notation which squeezes 3 into the time of 2, that would need _dotted_ minims/halfs.
Comment: How does the reader know (short of counting time across the whole bar) that the triplet there is 3-in-the-time-of-4 instead of the more usual 3-in-the-time-of-2?
Comment: @gidds Seems to me the 3-for-two would normally be notated with quarters. Also, as a performer, I like the triplet notation; it always makes you stop for a second and think, but it's visually easier to parse than the tie-based one.
Comment: @gidds Fair point, I forgot we were in 12/8. But I'm not sure, tbh, whether one ever mucks about with dotted notes in a tuplet...
Comment: This is just wrong!    A triplet of dotted-half notes would be an option.
Answer: Another alternative is to change the time signature to 3/2 for this measure, and then back to 12/8. As with Richard's suggestion of a triplet notation, it's best saved only for certain occasions.


google cloud print on linux

Question: i'm using Google apps, and i would like to use Google Cloud Print but all my printers are "classic", and for what i understand it is possible to use a classic printer if i have a running pc with my google account on chrome.is there any service or something that i can install it on my CentOS server so it can be always running and sharing printers too google Cloud Print?
Comment: You may have better luck in superuser.
Answer: I have that at home. The Printing service for Linux is called CUPS and you can install it in any Linux.

yum install cups

after that, just browse to your_centos_ip:631 and add a printer.
After that, i believe you have to login into your google account in that machine and add the printer in google cloud print service.
EDIT: Check here the help from google cloud printing.

http://support.google.com/cloudprint/bin/answer.py?hl=en&answer=1686197&p=mgmt_classic
Comment: Don't think CUPS interacts with Google Cloud Print.
Comment: No, but google can access the printers. You can add a "Cloud ready printer" and a "Classic Printer". I mention cups, because it's the responsible for printing in Linux. (response edited). I only use Linux and @ home i have this working
Answer: I use a python project called cloudprint.  It's in the Ubuntu repositories, I don't know about CentOS, check your repos.  Alternatively, you could just download it from Github.  It's fairly straight forward and works pretty well.

google cloud print on linux


Are derivatives of public domain settings less distinctive than of copyright-protected ones?

Question: e.g If a video game has over 100 characters, all based on public domain characters (those from old literature, folklore, etc.), can another game have almost exactly these amount of characters, with most of them being characters featured in the previous game? (Assuming the characters are based on the original public domain characters and not the specific versions of that game)
Answer:
Are derivatives of public domain settings less distinctive than of copyright-protected ones?

Maybe, but without more detail, the legal relevance of this fact is unclear.
If a work is independently created, it is not a derivative work

Assuming the characters are based on the original public domain characters and not the specific versions of that game

If a second work is not based on the first work, then the second is not a derivative of the first.
See the definition in 17 U.S.C. § 101:

A "derivative work" is a work based upon one or more preexisting works, such as a translation, musical arrangement, dramatization, fictionalization, motion picture version, sound recording, art reproduction, abridgment, condensation, or any other form in which a work may be recast, transformed, or adapted.

Independent creation of a work, based on public-domain material, will not be a derivative work of some other work also created in the mean time.
Copyright protection for any derivative would be limited in any case
See The United States Copyright Office Circular 14:

The copyright in a derivative work covers only the additions,
changes, or other new material appearing for the first time
in the work. Protection does not extend to any preexisting
material, that is, previously published or previously registered works or works in the public domain or owned by a third party.
Answer: Copyright does not work that way
Distinctiveness is not based on what your character is inspired by, but how it is executed. Let me describe to you a character that is public domain, and then one that is, in its execution, quite distinctive:

A beardy guy with a belt he required to lift his hammer to control lightning, choleric, likes beer, and prone to going out on adventures. Also, married a giant while wearing drag and then killed every witness to get back his hammer, and made sure the most lovely woman would adopt the two cat cubs from a single dad-cat.
A clean-shaven blonde beefcake clad in blue, black, and red, throwing a hammer, calling lightning from the sky, very generous, and a goody two shoes speaking in Shakespearean English.

Yes, those both are Thor. One is the Edda, the other is Marvel. They are both very distinctive and yet, they are different. And in fact, the character design of the Marvel-Thor is so different, that it is but for some small things, quite copyrightable as an artistic expression - and will be for quite some time because Jack Kirby only died in 1994, Stan Lee in 2017 and Larry Lieber is very much still alive.
To the law, these things matter:

Is the character's expression under copyright? the Saga-Thor is older than paper, and thus isn't, so the inquiry stops here. But Marvel-Thor was created in 1962, and still has some copyright left in the tank in many jurisdictions, and in others, the clock isn't even ticking yet because Lieber is still alive.
Is the inspired character a carbon copy, heavily inspired (derivative work), or substantially different? If my Thor is more a beardy guy with a potbelly and a hammer-engraved shotgun throwing lightning who is constantly on the hunt for wolves, then that is very much different from the Marvel-Thor and even Saga-Thor, even if all share common traits and a name.
Is my use of your character Fair Use or Fair Dealing, such as to deconstruct it in a parody? For example, if I took a lot of the Marvel-Thor look-and-feel and told a story that deconstructs the whole Superhero genre, that's Parody.

So, in theory, you and me could both make a game that uses out-of-copyright characters and depict them as in that media and neither can sue the other. Both of us can use Saga-Thor. But if you use the Potbelly-Wolfhunter-Thor I described above, you'd possibly infringe on the copyrights that I have in the changes and expression of my Thor.


Graph States subjected to finite erasures

Question: The appendix to the paper Graph States as a Resource for Quantum Metrology states that when graph states subjected to finite erasures, $$G\Rightarrow Tr_\vec{y}G.$$ While more explicitly he explains the formula as
$$G_\vec{y} = \mathrm{const}\times\sum_{\vec{y}}Z_\vec{j}\lvert G\rangle\langle G\rvert Z_\vec{j}.$$
I was wondering, how can these two statements the same, i.e., why the erasure error can be stated as the operation of $Z$? I know $I + Z$ can be the erasure error, but how can $Z$ alone stand for the erasure error?
Comment: Have you checked section $6$ (specifically proposition $8$ on page $46$) of the review article ["entanglement in graph states"](https://arxiv.org/abs/quant-ph/0602096)? The proof is on the next page.
Comment: I've checked, and the question is amended, avoiding passing the wrong meaning.
Comment: I just realized you changed the question - so that makes my answer moot. Have you tried factoring out the $\frac{1}{2}(I + Z)$? If you delete for instance $2$ qubits, you'll get a summation over $II, ZI, IZ$ and $ZZ$ - exactly a sum over $j \in \{00,01,10,11\}$, or in other words every combination of $0$'s and $1$'s for the traced away qubits.
Answer: The idea of erasure being projection onto $|0\rangle$ is perhaps misleading in this context (my fault for mentioning it in a comment without having looked at the full details of what this specific paper did). This paper does not project the set of qubits $y$ onto the $|0\rangle$ state. Instead, they trace out those qubits. Perhaps the best way of writing this, to be more consistent with the notation is
$$
G\rightarrow \text{Tr}_yG\otimes \frac{I_y}{2^{|y|}}.
$$
If you think of $G$ as some sum of terms in the Pauli basis,
$$
G=\sum_{x\in\{0,1,2,3\}^n}\alpha_x\sigma_x,
$$
then what the partial trace is doing is selecting all the $x$ for which the $y$ components of $\sigma_x$ are all $I$.
So, let us consider terms
$$
\sum_{z\in\{0,1\}^{n}}'Z_z\sigma_xZ_z.
$$
I'm using the notation $\sum'$ to denote the fact that while $z\in\{0,1\}^n$, I'm only summing over terms where $z$ is 0 on every site not specified by $y$ or the neighbours of $y$ (i.e. those not in the set $L_y$ in the paper's notation).
There are two possibilities for the fixed $x$ and a particular $z$ - either $Z_z$ commutes or anti-commutes with $\sigma_x$.
$$
Z_z\sigma_xZ_z=(-1)^{x'\cdot z}\sigma_x.
$$
Here I'm using $x'$ to denote a binary string derived from $x$ which is 1 for a given site if $x$ yielded an $X$ or $Y$.
Thus,
$$
\sum_{z\in\{0,1\}^{n}}'Z_z\sigma_xZ_z=\sigma_x\sum_{z\in\{0,1\}^{n}}'(-1)^{x'\cdot z}.
$$
This is $2^{|L_y|}\sigma_x$ if $x'$ is 0 on all the sites $y$ and its neighbours. It's 0 otherwise. This immediately excludes any stabilizer (product of generators) that contains a generator (of the form $XZZZ\ldots Z$) where the $X$ acts on one of the sites to be traced out, or one of its neighbours. Since all generators act on a single vertex and its neighbours, this means that the only terms remaining do not act at all on the sites being traced out, i.e. they are $I$ on those sites. Exactly the set of stabilizers you were trying to select.


Connect two close parallel train tracks in factorio?

Question: I have two parallel tracks in Factorio.  I'd like to connect them so a train can move from one to the other.  The planner just does not seem to allow it, no matter how I move around.  Sure, it's too close, but can I turn the train further, then closer?
Comment: If you'd rather stick with the track separation you have instead of using the minimum-distance crossover shown in the answer, consider making a station (really two stations, I guess) where items are transferred from a train on the lower track to a train on the upper track.
Answer: To be able to make a crossover without going apart and together again, space your parallel tracks by 6 tiles (3 track widths; gap between them of of 4 tiles/2 tracks). Your tracks are too close by 2 tiles / 1 track width, as Factorio only has one size of curved track section, which goes too far for this situation.
Whether or not you change the layout, to get the rail planner to make a connection to the existing track, press the rotate key R one or more times while using the planner; this will allow you to choose the direction the track ends in to align with the existing track rather than it picking whichever is simplest to plan. Each press will rotate the track end by 45 degrees.

This is the smallest possible connection between parallel tracks spaced at 4 tiles:

This is the compact crossover that is possible spaced at 6 tiles:
Answer: In the next version of Factorio, 2.0, tracks will be able to connect without the two-track skip.
Friday Facts #377 - New new rails
The release date is undetermined at this time.
Here's a picture from the announcement:


Ubuntu 16.04 Unity solid black panel instead of being transparent

Question: Im having really weird issue going on with unity desktop. As you can see on screenshot my main monitor(on left) is having panel solid black and my secondary monitor(on right) is having properly transparent panel. In CCSM I've set Opacity to 0, I tried executing 'unity' command but that did not help.
Answer: I was able to solve this using following commands
<code>unity-tweak-tool --reset-unity
dconf reset -f /org/compiz
setsid unity
</code>
First command is reseting all settings back to default in unity-tweak-tool, second command is reseting compiz to default and finally last command is restarting unity.


How does a Fenestron remove or reduce the tip vortex losses in a helicopter?

Question: How are Fenestrons (or fantails) able to reduce the tip vortex losses in a helicopter?
Comment: it's basically a ducted fan: http://aviation.stackexchange.com/questions/13995
Comment: A link to some background information would be really helpful here: I have no idea who or what Fenestron is
Comment: Which tips, tail or main rotor?  If main rotor, they don't.  If tail rotor, the duplicate covers this.
Answer: There are basically two effects here:

One is the ducted fan effect. Ducted fans are more efficient than open fans, specifically creating smaller vortices at the blade tips.
The other is the fact that the tail rotor of a helicopter is not situated in an area with almost linear airflow along the rotor axis. It is also submitted to:

A steady flow due to helicopter forward motion. This is coming from the side of the rotor, so affects opposite rotor blades differently.
A buffeting flow from the h/c main rotor. This is an unsteady flow, also coming laterally from the point of view of the tail rotor (actually, the top).

Fenestron tail-rotor ducts can be considered a fairing that reduces airflow across the rotor. The end result is that the rotor blades are in a much smoother flow that helps reduce unwanted turbulence. This is one of the reasons such rotors are quieter than regular open tail-rotors (the other being the fairing material absorbing some of the noise).


3 or 4 characters long username from security point of view

Question: I have on my site the ability for the user to choose his/her username that is 4-20 characters long.
But some users could have names like "Amy" "Eva", "Ian" etc.
Should I stick with 4 letters or go to 3 letters?
Are there any disadvantages from security point of view?
I am using trim and xss filt. on every user input and the words like admin etc. are restricted in my callback method.
Is it safe to go to 3 from 4 letters?
Comment: It can be an issue if attacker is using exaustive search, for both username and password. But it's not likely, as you mentioned you have an admin user, so attacker already knows at least one username. It will be a change in security but I don't think it's dramatic and worth all the hustle. Usernames are not secret and you should not treat them like such. Put constraints on passwords not usernames :).
Comment: I think you should be bothered only with username duplication, and information disclosure if username already taken :) (it is not always an issue).
Comment: So 3 or 4 characters is no difference - from the security point of view? Because the tank auth library (I am using CodeIgniter framework) has default settings for min username lenght set to 4 and max to 20. That's why I am asking if it is a reason for that or not? Another example that comes to my mind right now is PIN code on my phone. It is also 4 cahracters long. But again it is password and not username ;). So, do you think it is safe to go with 3 characters? If yes, try to post your answer as an answer instead of comment so I can possibly chose your answer as the winning one. Thanks.
Comment: Its pretty safe to assume there is a reason the defaults are set 4-20 characters.  Unless you understand those reasons, and only the author of CodeIgniter could make those reasons known, I wouldn't be changing defaults.  The only exception is if somebody who understood the reasons said otherwise, for example, some of the defaults in a PHP installation can be unsafe and the typical advice is to change them to something else.
Comment: It is a library Tank Auth Library. He is not the author of CodeIgniter PHP framework. Do you have any valid arguments to support your statement"Its pretty safe to assume there is a reason the defaults are set 4-20 characters."?
Comment: even 1 char would be OK :)
Comment: What of two characters long do you know?
Answer: There's no difference from a security perspective - the authentication strength should come from the password, not the username.
However, I wouldn't put a minimum of 3 characters on a username. In China alone, there are over 700,000 people with the given name Na or Li, and there are plenty more one-character and two-character names. Add that to the fact that names don't even need to be made of ASCII letters, and you're running into problems. Granted, you can probably enforce ASCII for your purposes, since most names consisting of non-Roman characters can be represented with the standard A-Z alphabet in some way.
I highly recommend you read Falsehoods Programmers Believe About Names and absorb the crazy facts within it. You can reasonably safely ignore some of the more esoteric issues (e.g. Klingon names) but be aware that there are people whose names do not fit in with any single standard model you can come up with.
Comment: The article you link seems to be mostly about real names. Usernames may be derived from real-names but they should be simplified so everyone in the organisation can remember and type them easilly. To me that means a-z, 0-9 and a handful of basic punctuation.


How can THD (Total Harmonic Distortion) be applied to compare between two signals ( for example between original and encoded signals)?

Question: I would like to compare between two signals (original signal and its encoded version) and plot the scores) as we do with STOI and PESQ.
should we calculate the THD for each single signal separately then subtract the scores?
Comment: We need more info about this: what type of signals are comparing and what is the nature of the encoding and decoding process. For perceptual encoders, THD is generally not a good quality metric.
Comment: Any mathematical definition of THD between two signal?
Comment: Thank you @Hilmar for your answer. Here is my explanation: I created a series of harmonics with different frequencies, then I saved it in a file (I'll call it signal_X). Afterward, I've encoded the previously created harmonics with LC3 codec (signal_X_hat). And I would like to compare between : signal_X and signal_X_hat.
Answer: Assuming that you know the set of fundamental frequencies, you should be able to calculate the THD for either signal (original or encoded) as $$\frac{\sqrt{v_2^2 + v_3^2 + \ldots + v_n^2}}{v_1}$$
where $v_1$ is the signal amplitude at the fundamental frequency and $v_2, \ldots, v_n$ are the signal amplitudes at the harmonics of interest for that fundamental frequency.
If there are more than one fundamental frequency, you would include all of them in the denominator and all of the harmonics of interest in the numerator. Since this is a normalized quantity, you can take the difference between the original and encoded signal to get a measure of introduced distortion.
See the Wikipedia link for details.


Colour picker Texture paint pie menu

Question: Is it possible to add the colour picker in the texture paint panel to a pie menu ?
Comment: Do you already have a pie menu script working tha tyou need to add it to, or are you asking if there is a pie menu out there that does this?
Comment: No I don't have it, I read the source code for the paint panel and can't figure anything out. I need the color picker in the custom pie menu.
Comment: Not a complete answer, so I will just leave as a comment - you can use Texture Paint Plus and check out how the BrushPopup operator works, and see if you can get the code figured out in a pie menu instead. https://github.com/artistCDMJ/texture_paint_plus/blob/master/__init__.py
Answer: Panels and Menus use the same methods to display properties and operators, the main difference is that a pie menu will show properties floating by themselves unless you create a box as a background for them.
To make your own pie menu start with the pie menu template that is included with blender.
To show a colour swatch that will pop-up a colour picker when clicked you use layout.prop() to display the colour property. To show the colour picker itself you can use layout.template_color_picker().
An example pie menu that shows both -

class ColourPie(bpy.types.Menu):
    bl_label = 'Set Colours'
    bl_idname = 'OBJECT_MT_colour_pie'

    def draw(self, context):
        ts = context.tool_settings
        ups = ts.unified_paint_settings
        ptr = ups if ups.use_unified_color else ts.image_paint.brush

        pie = self.layout.menu_pie()
        row = pie.row()
        # add a colour swatch that can popup a colour picker
        row.prop(ptr, 'color')
        box = pie.box()
        #show the colour picker directly
        box.template_color_picker(ptr, 'color', value_slider=True)

Colour picker Texture paint pie menu


Length of CSRF Token

Question: Is there any standard length of the token which should be used while generating the random tokens? Should we use the same standard which we use for generating Session IDs?
Answer: I would consider a 128 bits of entropy in a token to be the de-facto standard. OWASP and CWE both recommend this as a minimum. 20 characters of Base64 (capable of 120 bits) is also handy for something in the URL. I would also note that in many cases poor seeding for those tokens creates problems. For one bit of reference, see the (kind of tastelessly decorated, but very informative) slides from http://samy.pl/bh10/.
Make sure you choose your entropy source well.
Comment: I think the 160 bit tokens you mentioned in the first version of your posting are so common because they are a nice round number of 20 characters. (Although it should be noted that the bit size of token is not equal to the amount of entropy dune to the limited range of printable characters).
Comment: @p_upadhyay I think that's a very secure approach.
Comment: Should we use the same standards which we use for generating Session IDs for generating CSRF tokens as well? Just curious..

Thanks Jeff for Samy's very informative presentation.
Comment: @Hendrik Base64 * 20 chars = 120 bits of entropy. I'll modify my answer again to be clearer... and I think 120 is "close enough" to be ok.
Answer: This is an old question, but I've had occasion to look into this question and decided to at least look into what some and CSRF libraries use by default and my results are as follows:
Django : 32 random characters from the set [a-zA-Z0-9] : 190.53 bits of entropy
Ruby on Rails : 32 bytes of entropy (encoded as base64) : 256 bits of entropy
Spring Security : UUID4 (actually, this seems to use a PRNG, not an RNG, if I'm not mistaken) : 122 bits of entropy
OSASP PHP CSRF Guard (https://www.owasp.org/index.php/PHP_CSRF_Guard) : 128 characters from the set [a-z0-9] : 661.75 bits of entropy
OWASP J2EE CSRF Guard : 32 characters in the set [A-Z0-9] : 165.44 bits of entropy
Oracle ATG version 10.1.1 : a standard Java "long" encoded using ascii base 10: 64 bits of entropy
Note that my sample is heavily biased toward frameworks of which I can access the source code and frameworks I'm familiar with.
I've specifically tried to find frameworks which use 64 bits or less of entropy to try and justify why ATG would use a standard Java "long" and have been unsuccessful, so my conclusion is that 64 bits is probably too short.
That said, assuming an attacker can do 100,000 requests per second, it should take around 2.93 million years on average to brute force a 64-bit CSRF token.  (And there shouldn't be more than one token in the whole token space, unlike with session id's.)  So, maybe 64 bits is enough.
2 ^ 63 / (100,000 * 60 * 60 * 24 * 365) = 2.93 * 10 ^ 6
Comment: Well, 32 characters from the set [a-zA-Z0-9] should be fine, but 32 characters from the set [ab] is definitely insufficient. Probably better is to measure your "minimum safe" threshold in terms of the number of bits of entropy inherent in the token generation process rather than the number of characters in the resulting string.
Comment: tdlr: 32 is the magic number :)
Thank you for looking into this.
Answer: In CSRF an attacker can make many guesses.  What if an employee visits an attackers site and then goes on Christmas vacation?  An attacker could make many millions of cross-site requests.  We have a similar concern for session id's.  If either value is obtained then session is compromised.   The same standards of strength should be applied to both CSRF tokens and Session IDs.
In both cases make sure the value expires. Can the attacker can't make 2^128 requests in a week,  but eventually he will be able to.  If your random number generator is weak, then you may think you have a 2^128th cryptographic nonce,  but it might be much less.

Length of CSRF Token


Is there any Automation Framework that supports both Web and Mobile Application?

Question: Currently we are working with an Angular JS application and performing E2E with Protractor in Jamsmine framework. I just need to know about the framework that supports both this Web application and Hybrid mobile application.
Answer: I declared to be heavily biased[1] but since you asked directly: Squish GUI Tester is available in editions for Web, Android, iOS and more that can be combined for hybrid testing. Be it for plain Web UIs, native mobile Apps or cases of WebViews embedded into native applications.
The way it works is based on an abstraction of UI elements in a toolkit-neutral model that can be used for test interactions and verifications. Python, JavaScript, Perl, Tcl or Ruby are available for scripting.
When looking for tools you may want to differ between those that solely rely on Automation interfaces and those that can interact with an application natively. Image-based interactions and verifications (including OCR) can be a nice plus in case of custom controls as well.
[1] due to my co-authorship of this tool.
Comment: Thanks @Harri.. I am looking for some open source tool also


In Inkscape is there an easy way to divide my document into equal sections?

Question: I'd like to import 6 pictures (.gif) into an Inkscape Document, and size them equally and place them, well-aligned, into separate sections of the document. My document is in Landscape mode, and for purposes of this exercise, I'd like to place the 6 pictures into two columns, with 3 rows (i.e., a 3 x 2 "table"). Is there any way to do this easily? The way I would think to approach this is to put in gridlines, and do some math to calculate where each of the gridlines should go, then snap the pictures to the appropriate gridlines. Is there an easier way, so that I can just divide the document and save doing the calculations? Also, aside from "eyeballing" it, is there a way to make sure each of the 6 pictures is "automatically" or easily scaled to equal dimensions? Thank you!
Answer: In Inkscape, the Object > Transform > Scale tab has an "apply to each object separately" option which could be used to make all selected objects the same dimensions.
Object > Arrange can be used to arrange selected objects in a grid.
Just be aware that Inkscape can't handle animated GIFs if you embed the images, they will become static. Although animated GIFs will work if you instead import them as linked files, and have the GIFs in the same directory as the saved SVG, and view the SVG in a browser.
Comment: Thank you! That worked well! To arrange in grid, I did this through a manual process, iteratively grouping by rows, then arranging and distributing, then iteratively grouping by columns, also arranging and distributing. Just curious if there's a way to arrange in a grid with just a click or two, or is the way I described above the only way?
Comment: For the grid, you could use an actual grid, or guides. There are extensions that allow you to create grid guides automatically. For 0.92: https://github.com/sambody/inkscape-guide-tools, for 1.0(beta): https://gitlab.com/Moini/inkscape-guide-tools/ .


How to perform post install codesign in CMake?

Question: I have a simple C++ application built using CMake. In macOS it can be allowed to dump core on crash by doing something like:
 add_custom_command(TARGET mytarget POST_BUILD
    COMMAND /usr/libexec/PlistBuddy -c "Add :com.apple.security.get-task-allow bool true" coredump.entitlements
    COMMAND codesign -s - -f --entitlements coredump.entitlements $<TARGET_FILE:mytarget>
    COMMAND rm -f coredump.entitlements
    VERBATIM)

This works for the built program (e.g. running as ./build/bin/mytarget) but after make install the installed program fails to start, error: Killed: 9
How can I perform the codesign step again after CMake install, or make the initial signing persistent through a make install?
Comment: `install(CODE ...)`?
Answer: Thanks to @Osyotr for pointing me in the right direction. I ended up with the following:
set(ENTITLEMENTS "${CMAKE_CURRENT_SOURCE_DIR}/src/mytarget.entitlements")
install(CODE "execute_process(COMMAND
   codesign -s - -f --entitlements \"${ENTITLEMENTS}\" \"${CMAKE_INSTALL_PREFIX}/bin/mytarget\"
   )" COMPONENT Runtime)


Sending data from html to python

Question: I'm doing a project called IoT based announcement system where the user has to type the lcd number and the information to be announced in a webpage and that data should be printed and also converted in text to speech form in the LCD and speakers interfaced to the raspberry pi. I have currently created a webpage and send those data to a database. Can anyone tell me how to send those data to the raspberry pi?
Thank you in advance
Comment: You need to do some research to identify a reasonable solution.  When you have that you should ask a more targeted, less broad, question.  At the moment it seems like you want to get design help on the cheap.
Answer: For, sending data from the web to the raspberry. You can use socket's, by using socket programming you can send your data from client to server.
You can refer socket details from below site.
https://docs.oracle.com/javase/tutorial/networking/sockets/definition.html

Sending data from html to python


Plugin migration - how to handle count in php8.1

Question: I am trying to migrate a plugin from Craft 3 to Craft4 .
The plugin basically checks the entry for a pdf asset and create a thumbnail asset from the PDF using Imagick to save with the entry.
I use to check for the presence of a thumbnail by doing :
<code>$thumbs = $entry->pdfThumbnailImage;

if(count($thumbs) > '0'){
 //more checking code
}
</code>
Since php8.1 count above returns:
<code>count(): Argument #1 ($value) must be of type Countable|array, craft\elements\db\AssetQuery given
</code>
I am super daft and rusty and wondered how other people are handling the change in count to check for a custom field asset.
Answer: <code>$thumbs = $entry->pdfThumbnailImage->all();

if(count($thumbs) > 0){
 //more checking code
}
</code>


why find need "{} \"?

Question: I use command of find, for example:
find . -name "*.log" -exec grep "running" {} \;

why the command of find need {} , a blank and \?
Answer: This is because of the -exec parameter: the {} is a placeholder for the file that will be passed to the command.
the semicolon (;) tells find that the -exec argument list is over, but since ; is also a shell operator, you need to escape it so that it reaches find: \;
-exec works like this: for every file that is found, the first argument after -exec (the command) is executed and all parameters up until the ; are passed as arguments to the command. The {} is then replaced by the current filename that is found by find.
Answer: {} is a placeholder for path, which find replaces with the actual found path.
\; terminates find's exec arguments. Without \ shell would treat it as shell statement terminator, hence it needs to be quoted with \ for the shell to pass ; it to find.
I'd say that ; was an unfortunate choice for find exec command terminator.
Note that {} \; sequence can be replaced with {} +:
   -exec command {} +
          This variant of the -exec action runs the specified  command  on
          the  selected  files, but the command line is built by appending
          each selected file name at the end; the total number of  invoca‐
          tions  of  the  command  will  be  much  less than the number of
          matched files.  The command line is built in much the  same  way
          that  xargs builds its command lines.  Only one instance of `{}'
          is allowed within the command.  The command is executed  in  the
          starting directory.

Answer: Just read the manpages
-exec command ;

          Execute  command;  true  if 0 status is returned.  All following
          arguments to find are taken to be arguments to the command until
          an  argument  consisting of `;' is encountered.  The string `{}'
          is replaced by the current file name being processed  everywhere
          it occurs in the arguments to the command, not just in arguments
          where it is alone, as in some versions of find.  Both  of  these
          constructions might need to be escaped (with a `\') or quoted to
          protect them from expansion by the shell.  See the EXAMPLES sec‐
          tion for examples of the use of the -exec option.  The specified
          command is run once for each matched file.  The command is  exe‐
          cuted  in  the starting directory.   There are unavoidable secu‐
          rity problems surrounding use of the -exec  action;  you  should
          use the -execdir option instead.

Answer: The backslash is an escape to protect the semicolon from being misinterpreted.
The braces are placeholders for the full path outputted by find.

why find need "{} \"?


Datacenter steal data from raid 1 server

Question: I have a server (HP DL380pG8) in one of data centers in my country. As I was thinking about securing my data, I was thinking about what if, someone in data center, extracts one of disks which are active in raid 1, and replaces that with another disk. Is this a common issue? What can I do to monitor this from ESXi?
I know its rare and maybe no one can do it in front of security cameras, guards, etc. But I want to make sure, data is not accessible this way (some alarm in ESXi, as soon as missing one disk or something similar)
thanks.
Answer: This is a discussion you need to have with your datacenter about security, access controls and their internal processes.
We can't help you other than saying that it's unlikely that someone would want your data enough to do this.
As for an alert, you won't be able to receive one in ESXi unless you have a vCenter server and the HP management agents installed in ESXi.
Alternatively, you can configure your ILO4 to send AlertMail on hardware health events.This would send an email on disk removal or failure.
Answer: Pity it's a Gen8 not a Gen9 as with most if not all Gen9 disk controllers you can buy (quite cheaply) a licence to encrypt any disk connected to the controller - this isn't a special disk, any disk will work - in fact the licence isn't even verified, you could just switch this feature on and buy the licence later. This is with Px4x series controllers btw, like the P440ar etc. You can buy one of these and add it to a Gen8 btw.
Comment: Thanks. I'm not expert in hardware topics. your answer and Ewwithes answer was useful. But I think yours is more reachable for me.
Answer: Definitely not common but if you have sensitive data on the server you would need to do something about it.
There's self-encrypting "FDE" disks where the disk's key stays in your controller and the disk will not be readable. Those disks are not much more expensive than ones without that feature.
In that case make sure you backup your raid controller's config to some other location or you will find that you'll also be locked out if the controller failed (and just you to blame).
You'll have to make a choice and test / document very hard if you wanna do that: it's NOT common to do outside of high security systems, be it corporate engineering, military or anything like that. You can do it, but then you also gotta be on top of it.
I'd instead start with contracty stuff, like getting it in writing that the ISP will shred failed disks within a defined time (costs money!).
And also, the easiest thing: Make note of your disks' serial numbers and if you see one have a weird intermittent failure, check if it still has the same serial.
On LSI you can also disable auto-rebuild of LUNs which means you got to manually ACK and start a rebuild. puts your data at a higher risk because the rebuild only takes off once you got around to doing it. But gives more security and that IS a common thing for professional environments.
(Typical hosting outfits will have autorebuild enabled, locked down datacenter might not)
In order of easyness to being effective:

contractual stuff (enterprises would have)
inventory tracking (hard proof, need to have. also good vs. mistakes)
monitoring (always good but it's like a camera. you can only watch the crime ;)
disabling automagic (but more reaction time + risk)
hw encryption (but more effort in backups)

Also keep in mind that any legal intervention tops any contract. (But I assume you're not stupid and not putting up a server for illegal stuff)
The same risk comes with any bad guy with physical access.


How can I have the LiveView of my camera displayed on a TV or Laptop screen?

Question: If I simply plug in my USB-HDMI cable to a TV or laptop from my camera is there a setting I need to turn On to switch my LCD screen to my TV or computer? My camera is a Nikon D600.
I don't want to control the camera with the TV or laptop. I just want to view the images right after I take them – just as the back of my camera would show.  It seems so simple but I can't find an easy answer.
Answer: Due to Intellectual Property constraints, most notebook or laptop computers as well as desktop models do not have an HDMI port that allows video signals to be brought in via the HDMI port. It is an output only port. This prevents someone from being able to connect a DVD or BlueRay player to their computer and copy protected content. In general the only devices that can accept an HDMI signal and display it are televisions and monitors.
If you are trying to connect your D600 to an HDMI monitor or TV via the camera's USB port using a cable designed for an MHL compliant USB port (such as many mobile phones use to output video to a screen) it will not work since the USB port on your D600 is not MHL compliant. Use a mini-HDMI to HDMI cable to connect the mini-HDMI port on your camera to the HDMI port on a television or monitor.
If you want to shoot with your camera connected to a laptop to view your work as you shoot, you need to use a tethering capable application on your computer and connect the D600 to the computer via a mini-USB to USB cable. Even though many tethering applications allow you to control your camera from the computer, most also allow you to retain control using the camera itself.
Comment: I used HDMI to HDMI to a new TV and it worked perfectly! Thanks for all your input!
Answer: Generally, if your camera has an HDMI output, then it will display the photos on the TV that it is plugged in to, but I'm not sure what you mean by USB HDMI cable?  USB and HDMI are not the same, there is a technology called MHL that allows HDMI to be output over the same physical port as USB if it has special hardware, however the D600 doesn't have this, it just has a compact HDMI port.  If you are trying to use an MHL adapter with the USB port, it is not going to work and may cause harm to the camera.
You also mention the HDMI connector on your laptop.  Your laptop almost certainly has an HDMI output, it can't be used in both directions.  You can run information out of the laptop to a TV, but you can't run HDMI from your camera in to the laptop.  Attempting to do this may even damage either the camera or your laptop.  If you plug the camera in to a TV via HDMI, then for most cameras, whatever would normally show up on the LCD should be displayed on the TV and the controls on the camera will function as normal.
Comment: @Erin - Just a moment ago I tried this _"If you plug the camera in to a TV via HDMI, then for most cameras, whatever would normally show up on the LCD should be displayed on the TV and the controls on the camera will function as normal."_ and it works as it should on a cheap Sony SLT model. Using the camera, taking photos and seeing it all on TV like in LiveView display; all OK.


Slow network speeds - what should I check?

Question: Users are reporting that it's taking a long time to access files on the network, browse intranet sites, etc. What should I check?
Answer: To check the latency on a network:
Run a continuous ping from the command line:
ping -t [destination IP DNS or hostname]
Do this:

From your PC to the users PC
Your PC to the file server
Your PC to Internet sites
etc.

If any of these are slow, then run:
tracert [destination IP DNS or hostname]
to see where the issue is.
To check the bandwidth of a network:
You will need to install bandwidth monitoring software, look at your network switches (if they support monitoring), look at router logs, etc.
http://performit.co.uk/network/troubleshooting.php has some good tips.
Comment: Which version of ping is this for? What is the `-t` flag? On stretch, I see `-t ttl ping only.  Set the IP Time to Live.`, on MacOS `-t timeout Specify a timeout, in seconds, before ping exits regardless of how many packets have been received.` Both of them give me an error when run without a value, e.g. `ping -t 18.104.22.168`.
Answer: Check the duplex settings on the network ports.
If one end of a network link is set to 100baseT full duplex, and the other is set to auto-negotiate, the auto-negotiating end will always go half-duplex.
This wouldn't reveal itself with simple ping tests, but any substantial traffic over the link will be a lot slower than it should be.
Answer: first tools I would use would be ping and tracert. These will let you know right away if packets are being dropped and where. Routing issues will also bubble up.
I've also seen it where proxies, configured incorrectly, can cause problems on a local network.
Answer: Incorrectly setup DNS server/settings can also slow things down.


How to boot an MBP from an external HD?

Question: I created a clone partition of my main drive with SuperDuper on an external (USB) drive.  How can I boot from it?
Answer: Press and hold the 'Option' key when you first start your Mac, which should then show you a list of bootable drives.  You should then be able to select your external drive and go.
Answer: In addition to Brad's answer, before you shut down you can connect the external disk, open the "Startup Disk" system preference item, and pick the startup image that you want.

How to boot an MBP from an external HD?


Finding death records for family members?

Question: How can I look up death records WITHOUT paying for them or joining a site?
Comment: Alas, little in this world is free. Nevertheless could you please [edit] your question to include at minimum the location and date of the death of which you are seeking a record – otherwise it is impossible to answer. Also you may like to take a look at our [tour] and [help] pages. Welcome to the site!
Answer: I shall assume you're asking about England and Wales.
Deaths post 1837 have been registered with the General Register Office (GRO).
You can search the death indices at Registration Services but you will need to register (free) so that might not meet your requirement.
An alternative is FreeBMD but the death indices there do not include age-at-death for all deaths, so may be less helpful than the GRO site.
In all cases, death registration indices will only provide information about the death registration district, quarter and year of the death registration and (maybe) age at death; to get full details you would need to order and pay for the death certificate.
Another alternative to find death registrations in some (not all) counties are the Local BMD indices accessed via UKBMD but again you will be limited to what is in the indices and you will not see the full certificate without paying for it.  (Deaths were registered at a Local register office, and later centrally indexed at the GRO, which is why there are two options for finding registrations.)
Neither FreeBMD or the local indices require you to register at a site.
Burial record in Parish registers may also provide you with the information you seek. FreeBMD has a sister site FreeReg for Parish Registers, but the coverage is nowhere near complete yet.  UKBMD can also point you to other optiions such as Online Parish Clarks and others who have transcribed records for some parishes; if you're lucky, you will find that somebody has covered your parish of interest.
And finally, FamilySearch has a wide range of historical records available that might yield what you want.
Answer: In the absence of you providing details about where and when the deaths occurred for which you seek records, I am going to make an assumption that it is Australia, so that even if this does not help you, it may help someone else who visits this Q&A.
The National Library of Australia provides a page on Australian birth, death and marriage records:

This guide to Australian birth, death and marriage (BDM) records
  provides:

Links to State and Territory Registry offices and to [their] freely accessible online indexes, where available

If I were looking for a family member in South Australia, where I come from, I would follow the link to South Australia where it says:

The South Australian Government Births, Deaths and Marriages Registry
  does not provide an online searchable index service. However,
  Genealogy SA does provide an equivalent service through their free
  Online Database Search.

If I know my family member's name and date of death within a 7 year range then that search should enable me to find a record of that death in its index.
Obtaining more details of a death in South Australia, like a death certificate (or transcript of it), is not free, but simply finding a record of it, like that below (for my great grandfather) is free:
<code>Year: 1943
Reg: 662/1786
Surname: STACY
Given Name: Clement Howard
Relative Name: undefined
District: Adelaide
</code>
By searching the internet you may be able to find a free source of death records that includes your family members.  To find the above site I started by typing:
http://www.google.com/search?q=death+records+free


BF3: How many points do you need to get a service star in vehicles?

Question: What are the points needed to get a service star in each vehicle?  I know it's 100 kills with the infantry weapons but I read that each vehicle has a different amount.
Answer: In vehicles, Service Stars are awarded for scoring the number of points which is equivalent to earning all the unlocks again. It's the same as the kits.
Here is the exact number for each applicable vehicle:

Tanks: 100,000 points
Attack chopper: 60,000 points
Scout chopper: 48,000 points
Mobile AA: 32,000 points
LAV: 90,000 points
Jets: 35,000 points
Answer: Vehicle service stars unlock once you've unlocked all of the possible upgrades for that vehicle.
I think the final upgrade unlocks around 100,000 points and I think this final upgrade comes with the first service star.
After that, I think you might obtain another star every 100,000 points, but I haven't seen anything on the website to confirm this, it just says "when the next service star level is reached"
http://battlefield.wikia.com/wiki/Service_Stars


Web Card Game , MySQL vs SQLite performance wise

Question: Been thinking of creating a js/PHP/MySQL game, with multiple players / games happening concurrently. Is there any chance SQLite might be faster for something like this than MySQL? Keep in mind that I'll propably test this on a shared hosting server...
Answer: Writing every single action to the database, like you are suggesting you are doing, is usually a bad idea.
You would do much better writing a real server, and update the database only once a match ends.
Comment: That entirely depends on the time requirements of the game. If it's a turn based or tick based game with a low update frequency (<1/sec or less) then there's no problem with writing it as a traditional database-oriented application.
Answer: You probably don't care. I'd suggest that maybe it's not necessary to use a database at all, and a commercial gaming company almost certainly uses a custom server process (not a web server at all). However, you can do whatever you like.
In particular, you're very unlikely to have either enough data or players that you will actually notice. Gaming data are very, very small unless you start storing huge amounts of historical reporting data for previous games. And if you do decide to start doing that, you can host historical data on independent servers so they can't interfere with new games.
Comment: By custom server process you mean php scripts that keep session data for game states? That's what I've come up to...
Comment: I mean, it uses a custom protocol, not HTTP, no PHP (probably not, anyway, PHP is hopeless for long-running server processes). As far as I know, all gaming sites (I mean gambling for real money of course!) use some Windows binary, activeX control, Flash or Java applet in the page, so they can use whatever protocol they like.
Answer: My advice is to look at a PHP interface that is database agnostic, so you can switch it later.


How to determine degree of polarization in time domain!

Question: I know there are methods to determine the degree of polarization of multi-dimensional signals, say [Bx(t), By(t)] -> DOP(f). Is there any way to extract a DOP for given vector time series in the time domain? Thanks!
Answer: You should probably use one of the algorithms for primary component (PCA) or independent component (ICA) investigation. They heavily relay on covatiance matrices and their eigenvalue-eigenvector decomposition.
If your time series represent an oscillation with dominant direction, the eigenvector for the maximum magnitude eigenvalue would represent that direction. If the signal is some kind of elliptic, the basis of eigenvectors would represent the oscillation ellipsoid dimensions. Degree of polarization is then easily yielded from relations of main-to-other eigenvectors magnitudes.