Path to becoming an audio engineer

Question: Can someone write down steps an totally beginner in EE and DSP needs to pass to become a audio engineer? From which subject to start with (math, electronics), and with which subjects to continue this road? My goal is to get a good knowledge in audio signal processing, things like creating sounds (sound synthesis), sound transformation, mixdown audio, understand fundamental things. I will be very grateful if someone give me instruction from where to start and what path to follow, and on what to mostly pay attention, I have a great desire to learn all of that, I have 6 years experience in electronic music production. Thank you very much!
Comment: by *"audio engineer"*, i presume you don't mean the practitioner who sits behind a big 40-channel mix board, mixing music and sounds and creating CDs.    you mean you want to design audio processing equipment?  like rack-mounted effects or stomp box?
Comment: No, I want to learn to design synth sounds I need, to transform sounds, to mixdown raw audio files.
Comment: these days you really don't need DSP for transforming sounds, it's all been abstracted away in good software. i would really recommend you get a demo of Max/MSP or get really good at making patches on your synth. you do not DSP. you need a careful ear some decent software and a lot of time and experimentation.
Comment: most of what @panthyon says is correct.  dunno how plug-ins work with Max/MSP, but i might assume VST plugs work with it, but the reason why plug-ins exist is because the DAW doesn't already do what you need to the sound.  now, if Zol wants to transform a sound in some way that an existing plug-in or function of a DAW (or whatever is the sound manipulation environment) does, then Zola is okay with it.  but if Zola wants to do something to the sound that he/she can articulate mathematically and there exists nothing else to do it, then maybe Zola needs to learn how to write some DSP code.
Answer: (TLDR: if you want to dive in I might recommend Will Pirkle's books Designing Audio Effect Plug-Ins in C++ and Designing Software Synthesizer Plug-Ins in C++ but you might be completely overwhelmed depending on your background)
First off, if you want to create new sounds, I love Max/MSP and that will get you creating new sounds quickly but it will not teach you DSP.
Before a mod closes this as off-topic or too open-ended, I will say this:
There is no recipe, no set list of steps. Period.
Or as Umberto Eco wrote in his famous thriller "Foucault's Pendulum"....there is no map.
Take that for what you will. I'm sure everybody's story who works with audio is different. I grew up messing around with 4-track tape recorders, and since I grew up with computers, started playing with digital audio workstations like Audacity and ProTools (Ardour during my hardcore linux purist phase), making demos and playing in bands. During this time I also tried my hand at BASIC and later scripting languages. I got interested in theoretical physics in high school, and majored in physics in college (where I made a lot of demo recordings with bands and learned how to solve problems, but not a lot of domain specific knowledge (which I think is a good thing)).
I didn't want to be a particle physicist and had met a professor who worked in architectural acoustics. I found a grad program that was able to pay me to think about sound and space (mostly psychoacoustics) for 4 years and earn my MS and PhD.
At the end of my PhD I met (through a random LinkedIn message I initiated) the CTO of a startup who was willing to transfer my skills in psychoacoustics to programming microcontrollers to do effects and equalization. My job got me started down the path of really doing synthesis and processing. I had (almost) no idea what I was doing, and that's when I really learned. I'm just starting on this journey of being able to digitally manipulate sound, and I find that there's just so much out there and it is totally fascinating.
Every day I realize I know so little, but take in what I can each day (and try not to get frustrated that I don't move faster). Understanding is a slow process that cannot be expedited.
That being said, if I had to do it all over again knowing what I know now (and how could I have really?), I would have taken as much math and programming as I could have in high school (which wasn't offered in Catholic school) and majored in electrical engineering (which wasn't offered at the liberal arts college I attended). EE is really where all this stuff stems from. I'm biased but I would say it doesn't hurt to study something about hearing science and psychoacoustics too. Music appreciation can fuel your enthusiasm.
Comment: well, i was EE and ABD in a PhD program.  i sorta wish i had double-majored in math/physics as an undergrad and done EE as a grad student.  dunno what would be best.  speaking of Will Pirkle, if the OP is on the North American continent, i might strongly suggest Music Engineering at U Miami.

Path to becoming an audio engineer


Is the electric field in the wires of the parallel circuit always the same and how that affects current?

Question: When we connect two resistors connected in parallel with a battery, it creates an electric field through this wire.
well, my question here:
Is the electric field in the main wire is the same as the two wires that are branched from the main? If so why the sum of the current in the two branched wires is the same as the current of the main wire?
Comment: English questions end with a single question mark, not two. Also, every post on this site is a question, so there is no need to say "question about" in the title. Please read our [FAQ on question titles](http://meta.physics.stackexchange.com/questions/6413/how-do-we-write-good-question-titles).
Answer: You've asked two questions in one. First, no: the electric field through the main wire is NOT the same as that through the two resistors. The electric field is a continuously varying field, and isn't necessarily the same at any two points in a circuit.
Second, you're overthinking this. It's seldom useful to consider the electric field when calculating current through a circuit. Using good old $V=IR$ will get you there in 99% of the cases.
On your specific second question, a current is a stream of electrons moving through a circuit element. If you have a single-loop circuit, then the number of electrons (the current) passing any one point in the circuit will be the same as at any other points. If your circuit splits, then the sum of the electrons (and thus the current) passing through each branch will equal the electrons (and thus the current) through the main circuit.
Answer: The electric field in an ideal wire is always zero.
To calculate the average electric field through a circuit element you take the voltage across the element and divide it by the length of the element. Since an ideal wire has the same voltage at both ends the voltage across the wire is zero and therefore the E field is also zero.
The voltage across a wire is independent of the current through the wire (it is always zero ideally). So the fact the current is different is irrelevant to the voltage or E field.


On Noetherian and Japanese rings

Question: Let $R$ be a Noetherian ring all of whose local rings are Japanese. Is $R$ necessary Japanese?
Comment: "In commutative algebra, an integral domain A is called an N-1 ring if its integral closure in its quotient field is a finite A module. It is called a Japanese ring (or an N-2 ring) if for every finite extension L of its quotient field K, the integral closure of A in L is a finite A module." - wikipedia
Comment: Wow. For 18 months this question had 0 votes and today it got 5 upvotes after a minor syntax edit. I guess syntax is pretty important 'round here.
Comment: EGA also only defines "Japanese" for noetherian domains. Basic result of Nagata (see EGA IV$_2$, 6.13.6) is that when localizations of a noetherian domain $R$ at all primes are Japanese then integral closure $R'$ in a finite extension $K'/K$ of fraction field is $R$-finite if and only if $R'_r$ is $R_r$-finite for some nonzero $r \in R$. Using EGA IV$_2$, 5.10.17 and 6.13.2--6.13.4, it then follows that your $R$ is Japanese iff each $R$-finite ring extension that is a domain has non-empty open normal locus in Spec. Not sure if it's of any use...
Comment: In fact, since your hypothesis is inherited by any domain that is a module-finite ring extension of $R$, to prove an affirmative answer in general it is equivalent to prove in general that your hypothesis implies that the normal locus in Spec($R$) contains a non-empty open set (which actually implies it is open, and conversely such openness is always true in the Japanese case; see 6.13.2--6.13.4 of EGA IV$_2$). Still seems like it may be a useless viewpoint on the question...
Answer: No, $R$ is not necessarily Japanese. What follows is a explicit example from a note that Rankeya Datta and I wrote, now available on his website.
Example. We use Hochster's example [Hochster, Ex. 1]; see one of my other answers for the relevant results therein. Let $I$ be the set of positive integers, and set
$$R_i := k[x_i^2,x_i^3] \qquad\text{and}\qquad P_i := (x_i^2,x_i^3) \subseteq R_i$$
for every $i$, where $k$ is a fixed algebraically closed field. Then, setting $R' := \bigotimes_{i \in I} R_i$, the ring
$$R := \Bigl(R' \smallsetminus \bigcup_{i \in I} P_iR'\Bigr)^{-1}R'$$
is a domain such that all of its local rings are excellent (hence Japanese), and such that the regular locus in $\operatorname{Spec}(R)$ is not open [Hochster, Prop. 1].
We claim that $R$ is not Japanese. By Hochster's construction (see [Datta–M, Rem. 4]), the ring $R$ is one-dimensional. But the regular locus is open for any one-dimensional Japanese domain [Datta–M, Lem. 5], and hence $R$ cannot be Japanese.

On Noetherian and Japanese rings


Fake Israel Visa Stamp on my Passport

Question: I have an problem here... I applied as DH in Israel not knowing that I was Transacting to a fake agent and the problem is they already stamped fake Israel Visa on my passport. I already traveled here in Qatar but the immigration denied my passport and they said that I will not work here, I will be going back to Philippines because of this fake visa stamp. What will I do?
Comment: @Traveller: we answer many question naively, possibly hinting some possible problems. We should always assume good faith (it was a good policy of Wikipedia), and we cannot in any case help people who tell us a lie. So I try to think most of people were naive youth travellers.But I think you are overgeneralizing. How many people used fake ESTA sites? Or visa facilitators (which help you not going to embassy in person, especially if you live away from capitals [or to provide you also invitation letters so you can travel alone). So I think the question could be genuine (I do not know Philippines)
Comment: I assume 'DH' means 'domestic help'? You could report the agent to the Filipino immigration authorities but unfortunately there may be little you can do to remove the entry denial from your travel history. Changing your passport would mean the fake visa itself would no longer be visible but your previous passport will remain associated with your travel record and you'll have to provide details in any future visa application that asks about previous passports or immigration problems.
Comment: Ask your government (the issuer). Probably your passport is not more valid. Very probably you need to have a new passport. Ask also Israely embassy, to be sure the visa is false and "reassure" them you are looking for a real visa (so not to being black listed)
Comment: How you where "denied"? With a stamp, or just they ask if you would voluntary renounce to enter? Sometime you get the offer to "go away" (and not entering) without prejudices.
Comment: @Traveller: new passport is not to hide the visa. The old passport is probably no more valid ("only authorized authorities may write in the passport"). If it was tampered on one place, it is easier to assume it is entirely tampered.
Comment: @Giacomo Catenazzi I think you may be being slightly naive. Everyone who uses a fake agency to get a visa and subsequently gets found out, says that they didn't know the agency was fake.
Answer: Tell your government that your passport was damaged/spoiled and request a new one.
This does not resolve your problem that Qatar considers you a liar. They will send you back and for the rest of your life you will have to answer "yes" if an application asks "have you ever been denied a visa or deported?"
This will make it much harder to get future visa, but if you lie about the denial and get caught they will definitively reject your application and add a ban in yet another country.
I'm sorry if that sounds unsympathetic and does not answer "what shall I do" but there is little you can do now. Look for work in the Philippines.
Comment: Are you deported if you are refused entry?
Comment: @gnasher729, Qatar seems to be throwing the OP out if I read the post correctly. For example the UK asks "Have  you  ever  been  deported,  removed  or  otherwise  required  to  leave  any  country [...]?"

Fake Israel Visa Stamp on my Passport


Difference between "weird content" and "weirdly content"

Question: What's the difference between weird content and weirdly content?
Answer: In the first case, content is a noun, and so the descriptor is an adjective (weird).
"I'm reading this book about humans who morph into rats; there's some pretty weird content in there."
In your second case, content is an adjective, and so the descriptor must be an adverb (weirdly).
"When Bill's father died, he was weirdly content.  It was as if a mass had been lifted off of his shoulders, and he no longer had to constantly prove himself."
Comment: Good answer, but it could use examples.  For instance, weird content in a cookbook that has recipes from Mars.  Weirdly content:  think of a situation where someone shouldn't be happy with a situation but they are anyway.  Illustrations are worth an upvote.
Comment: @WS2 Yes, but for those people, it still might seem weird at the time.
Comment: @deadrat Excellent advice. Zabari: now a very nice answer.
Comment: +! for the grammatical explanation. But in your second example I would not agree that *weirdly* was an appropriate adverb. There is nothing *weird* about such a feeling. A lot of people in their sadness and grief experience a sense of new-found independence, when their parents pass.
Answer: For those to make sense, you have to interpret them like so:

weird content

Content here is a noun (CON-tent), meaning that which is contained—such as the content (text) of an article, for example. If an article is weird, it will have "weird content".

weirdly content

Content here is an adjective (con-TENT), meaning satisfied or at peace. Someone who is content in a weird way—such as when the circumstances might normally lead to someone not being content—you might be able to describe them as "weirdly content". (I wouldn't encourage you to rush to use this expression, though, as it's a little odd.)


Does a grass path block spread grass to adjacent dirt blocks?

Question: When a grass block is turned into a grass path block with a shovel, does it continue to propagate grass to adjacent dirt blocks, or is the grass then "dead"?
Answer: I have run an experiment and grass path does not spread grass to dirt.

Setting the random tick speed to 1,000 meant that things like wheat growing or grass spreading in this case are a lot faster with the default being 3. I suspect this is because the two blocks are stored differently. Grass is minecraft:grass whereas path is minecraft:grass_path.
Answer: No. Grass paths will not spread grass, which means you can keep the area barren if you want to.


OpenGL ES Perform Selector After Random Delay

Question: I am working on an OpenGL ES application where I have a spaceship with 6 guns. Each gun uses keyframe animation to interpolate between 2 sets of vertices of a start and end position.
I have a method rotateGun: that I pass the gunNumber variable to that refers to which gun should fire. When rotateGun: fires, it creates a laser blast that I move away from the ship through a vector pointing down the gun barrel at it's location when the method is called. This all works fine but I want to add random time intervals for each gun to fire since right now they appear to fire at the same time.
I've tried to create a time delay and fire off my rotateGun: method using performSelector:afterDelay:, but this doesn't work. I then attempted to use the method mainGunFire: after a delay and then call rotateGun: on the main thread… this also didn't work. By "didn't work" I mean that the NSLog I inserted just before my drawing calls within the rotateGun: method does print, but the guns and blasts are never drawn.
If I simply do a performSelectorOnMainThread to call rotateGun:, then the guns and blasts are drawn as before and the blasts appear to fire at the same time. I'm clearly not understanding something. Can someone please help me understand how to slightly randomize my laser blasts so they don't all fire at the same time? Thanks!
// Randomly Fire Gun
- (void)mainGunFire:(NSNumber *)gunNumber {

    // Perform the Gun animation and fire on main thread
    [self performSelectorOnMainThread:@selector(rotateGun:) withObject:gunNumber waitUntilDone:YES];

}

// Draw and Rotate the Guns
- (void)drawRotateGuns {

    // Only shoot if this is not a ship life
    if ( self.isLife == NO ) {

        // Gun 1

        // Set the pass variable to 1 and call the method
        // after a variable amount of time
        int randomTime = 0;
        //[self performSelector:@selector(mainGunFire:) withObject:[NSNumber numberWithInt:1] afterDelay:randomTime];
        [self performSelectorOnMainThread:@selector(rotateGun:) withObject:[NSNumber numberWithInt:1] waitUntilDone:YES];

        // Gun 2 ...

        // Gun 3 ...

    }
}

Comment: `[NSNumber numberWithInt:1]` - insert random value instead of 1. In general your approach is wrong in design, I would recommend to use ready open-source engine ;)
Answer: The easiest solution is to use !(rand()%some_number) instead of 1. Experiment with some_number value (it must be different for each gun). But it should be not very big.
For example if you use 2, then probability of !(rand()%2) == 1 is about 0.5. So if you're rendering 60 frames per second you'll get about 30 fires per second. For the !(rand()%20) you should get about 3 fires per second. Hope you get it. Some pseudocode:
if( !(rand()%2) ) {
     [gun1 fire];
}

if( !(rand()%3) ) {
     [gun2 fire];
}


how to find duplicated permalinks?

Question: I've got a duplicated permalink somewhere, so I can't name the new one like that. Normally, I simply check the other posts, categories, media, even on the thrash. But this time I can't find any content with that permalink. I took a look to the database, did some search, but really can't find. It's strange. Is there any way to do a deeper search, or maybe some plugin that helps you cleaning up duplicated permalinks?
Comment: If you can't find it, how do you know it exists?
Comment: "so I can't name the new one like that"
Comment: So your question is actually about slugs not permalinks?
Answer: This can be a real pain, I know firsthand. The obvious place (that I sometimes forget) is your Trash folder. If it's not there, I would suggest re-saving permalinks.
As a last resort, I'd do what you said... a bunch of searches of the database. One time a plugin had auto-generated a page, and after disabling and deleting the plugin, I found the bad URL in the transients (the autosave stuff that WP does).
Good luck!

how to find duplicated permalinks?


Help with Repetier firmware variables (Dimension Dual Delta - J Group Robotics)

Question: So I'm finally building a new firmware (Repetier) since my current one can't be edited. It is a Delta printer and is explained in detail here: Help with Repetier firmware (probably locked and licensed)
There are many variables that I couldn't find in the EEPROM. Can someone please explain those to me (listed below)? I've listed only the ones I feel are the most important for now.
General and Dimensions:

KILL_METHOD
STARTUP_GCODE
DELTA_FLOOR_SAFETY_MARGIN_MM
Max. horizontal radius (DELTA_MAX_RADIUS): I have "max printable
radius" and "delta radius" A(0), B(0) & C(0) each.
Radius error column A/B/C (DELTA_RADIUS_CORRECTION_A/B/C): Could
this be the delta radii A(0), B(0) & C(0)?

Z-correction (distortion correction)

Full correction until (FC) or DISTORTION_START_DEGRADE
Reduce correction to zero at (RZ) or DISTORTION_END_HEIGHT
Correction radius (DISTORTION_CORRECTION_R)
Update every x computations (DISTORTION_UPDATE_FREQUENCY)

I have the following in EEPROM:

Z-probe height [mm]
Max. z-probe - bed dist. [mm]
Z-probe speed [mm/s]
Z-probe x-y-speed [mm/s]
Z-probe offset x [mm]
Z-probe offset y [mm]
Z-probe X1 [mm]
Z-probe Y1 [mm]
Z-probe X2 [mm]
Z-probe Y2 [mm]
Z-probe X3 [mm]
Z-probe Y3 [mm]
Z-probe bending correction A [mm]
Z-probe bending correction B [mm]
Z-probe bending correction C [mm]

Stepper

ENABLE_BACKLASH_COMPENSATION
ALLOW_QUADSTEPPING

Endstops

ENDSTOP_PULLUP_X_MIN/ENDSTOP_X_MIN_INVERTING
ENDSTOP_PULLUP_Y_MIN/ENDSTOP_Y_MIN_INVERTING
ENDSTOP_PULLUP_Z_MIN/ENDSTOP_Z_MIN_INVERTING
ENDSTOP_PULLUP_X_MAX/ENDSTOP_X_MAX_INVERTING
ENDSTOP_PULLUP_Y_MAX/ENDSTOP_Y_MAX_INVERTING
ENDSTOP_PULLUP_Z_MAX/ENDSTOP_Z_MAX_INVERTING

Fused Filament Fabrication

EXTRUDER_SWITCH_XY_SPEED

Also, how do I find out which temperature sensors are being used for the extruders? Where are they located?
Here's the EEPROM data:
<Repetier-Firmware-EEPROM>
<epr pos="1028" type="0" value="0">Language</epr>
<epr pos="75" type="2" value="115200">Baudrate</epr>
<epr pos="129" type="3" value="32.752">Filament printed [m]</epr>
<epr pos="125" type="2" value="21644">Printer active [s]</epr>
<epr pos="79" type="2" value="0">Max. inactive time [ms,0=off]</epr>
<epr pos="83" type="2" value="360000">Stop stepper after inactivity [ms,0=off]</epr>
<epr pos="11" type="3" value="80.0000">Steps per mm</epr>
<epr pos="23" type="3" value="200.000">Max. feedrate [mm/s]</epr>
<epr pos="35" type="3" value="20.000">Homing feedrate [mm/s]</epr>
<epr pos="39" type="3" value="10.000">Max. jerk [mm/s]</epr>
<epr pos="133" type="3" value="-140.000">X min pos [mm]</epr>
<epr pos="137" type="3" value="-140.000">Y min pos [mm]</epr>
<epr pos="141" type="3" value="0.000">Z min pos [mm]</epr>
<epr pos="145" type="3" value="140.000">X max length [mm]</epr>
<epr pos="149" type="3" value="140.000">Y max length [mm]</epr>
<epr pos="153" type="3" value="313.280">Z max length [mm]</epr>
<epr pos="59" type="3" value="2000.000">Acceleration [mm/s^2]</epr>
<epr pos="71" type="3" value="2000.000">Travel acceleration [mm/s^2]</epr>
<epr pos="881" type="3" value="355.200">Diagonal rod length [mm]</epr>
<epr pos="885" type="3" value="186.990">Horizontal rod radius at 0,0 [mm]</epr>
<epr pos="925" type="3" value="140.000">Max printable radius [mm]</epr>
<epr pos="891" type="1" value="70">Segments/s for travel</epr>
<epr pos="889" type="1" value="180">Segments/s for printing</epr>
<epr pos="893" type="1" value="0">Tower X endstop offset [steps]</epr>
<epr pos="895" type="1" value="0">Tower Y endstop offset [steps]</epr>
<epr pos="897" type="1" value="0">Tower Z endstop offset [steps]</epr>
<epr pos="901" type="3" value="210.000">Alpha A(210):</epr>
<epr pos="905" type="3" value="330.000">Alpha B(330):</epr>
<epr pos="909" type="3" value="90.000">Alpha C(90):</epr>
<epr pos="913" type="3" value="0.000">Delta Radius A(0):</epr>
<epr pos="917" type="3" value="0.000">Delta Radius B(0):</epr>
<epr pos="921" type="3" value="0.000">Delta Radius C(0):</epr>
<epr pos="933" type="3" value="0.000">Corr. diagonal A [mm]</epr>
<epr pos="937" type="3" value="0.000">Corr. diagonal B [mm]</epr>
<epr pos="941" type="3" value="0.000">Corr. diagonal C [mm]</epr>
<epr pos="1024" type="3" value="1.000">Coating thickness [mm]</epr>
<epr pos="808" type="3" value="0.800">Z-probe height [mm]</epr>
<epr pos="929" type="3" value="10.000">Max. z-probe - bed dist. [mm]</epr>
<epr pos="812" type="3" value="5.000">Z-probe speed [mm/s]</epr>
<epr pos="840" type="3" value="70.000">Z-probe x-y-speed [mm/s]</epr>
<epr pos="800" type="3" value="0.000">Z-probe offset x [mm]</epr>
<epr pos="804" type="3" value="0.000">Z-probe offset y [mm]</epr>
<epr pos="816" type="3" value="-95.260">Z-probe X1 [mm]</epr>
<epr pos="820" type="3" value="-55.000">Z-probe Y1 [mm]</epr>
<epr pos="824" type="3" value="95.260">Z-probe X2 [mm]</epr>
<epr pos="828" type="3" value="-55.000">Z-probe Y2 [mm]</epr>
<epr pos="832" type="3" value="0.000">Z-probe X3 [mm]</epr>
<epr pos="836" type="3" value="110.000">Z-probe Y3 [mm]</epr>
<epr pos="1036" type="3" value="0.000">Z-probe bending correction A [mm]</epr>
<epr pos="1040" type="3" value="0.000">Z-probe bending correction B [mm]</epr>
<epr pos="1044" type="3" value="0.000">Z-probe bending correction C [mm]</epr>
<epr pos="880" type="0" value="1">Autolevel active (1/0)</epr>
<epr pos="106" type="0" value="1">Bed Heat Manager [0-3]</epr>
<epr pos="107" type="0" value="255">Bed PID drive max</epr>
<epr pos="124" type="0" value="80">Bed PID drive min</epr>
<epr pos="108" type="3" value="196.000">Bed PID P-gain</epr>
<epr pos="112" type="3" value="33.000">Bed PID I-gain</epr>
<epr pos="116" type="3" value="290.000">Bed PID D-gain</epr>
<epr pos="120" type="0" value="255">Bed PID max value [0-255]</epr>
<epr pos="1020" type="0" value="0">Enable retraction conversion [0/1]</epr>
<epr pos="992" type="3" value="3.000">Retraction length [mm]</epr>
<epr pos="996" type="3" value="13.000">Retraction length extruder switch [mm]</epr>
<epr pos="1000" type="3" value="40.000">Retraction speed [mm/s]</epr>
<epr pos="1004" type="3" value="0.000">Retraction z-lift [mm]</epr>
<epr pos="1008" type="3" value="0.000">Extra extrusion on undo retract [mm]</epr>
<epr pos="1012" type="3" value="0.000">Extra extrusion on undo switch retract [mm]</epr>
<epr pos="1016" type="3" value="20.000">Retraction undo speed</epr>
<epr pos="200" type="3" value="93.000">Extr.1 steps per mm</epr>
<epr pos="204" type="3" value="150.000">Extr.1 max. feedrate [mm/s]</epr>
<epr pos="208" type="3" value="20.000">Extr.1 start feedrate [mm/s]</epr>
<epr pos="212" type="3" value="5000.000">Extr.1 acceleration [mm/s^2]</epr>
<epr pos="216" type="0" value="3">Extr.1 heat manager [0-3]</epr>
<epr pos="217" type="0" value="230">Extr.1 PID drive max</epr>
<epr pos="245" type="0" value="40">Extr.1 PID drive min</epr>
<epr pos="218" type="3" value="7.0000">Extr.1 PID P-gain/dead-time</epr>
<epr pos="222" type="3" value="2.0000">Extr.1 PID I-gain</epr>
<epr pos="226" type="3" value="40.0000">Extr.1 PID D-gain</epr>
<epr pos="230" type="0" value="255">Extr.1 PID max value [0-255]</epr>
<epr pos="231" type="2" value="0">Extr.1 X-offset [steps]</epr>
<epr pos="235" type="2" value="0">Extr.1 Y-offset [steps]</epr>
<epr pos="290" type="2" value="0">Extr.1 Z-offset [steps]</epr>
<epr pos="239" type="1" value="1">Extr.1 temp. stabilize time [s]</epr>
<epr pos="250" type="1" value="150">Extr.1 temp. for retraction when heating [C]</epr>
<epr pos="252" type="1" value="0">Extr.1 distance to retract when heating [mm]</epr>
<epr pos="254" type="0" value="255">Extr.1 extruder cooler speed [0-255]</epr>
<epr pos="300" type="3" value="93.000">Extr.2 steps per mm</epr>
<epr pos="304" type="3" value="150.000">Extr.2 max. feedrate [mm/s]</epr>
<epr pos="308" type="3" value="20.000">Extr.2 start feedrate [mm/s]</epr>
<epr pos="312" type="3" value="5000.000">Extr.2 acceleration [mm/s^2]</epr>
<epr pos="316" type="0" value="3">Extr.2 heat manager [0-3]</epr>
<epr pos="317" type="0" value="230">Extr.2 PID drive max</epr>
<epr pos="345" type="0" value="40">Extr.2 PID drive min</epr>
<epr pos="318" type="3" value="7.0000">Extr.2 PID P-gain/dead-time</epr>
<epr pos="322" type="3" value="2.0000">Extr.2 PID I-gain</epr>
<epr pos="326" type="3" value="40.0000">Extr.2 PID D-gain</epr>
<epr pos="330" type="0" value="255">Extr.2 PID max value [0-255]</epr>
<epr pos="331" type="2" value="0">Extr.2 X-offset [steps]</epr>
<epr pos="335" type="2" value="0">Extr.2 Y-offset [steps]</epr>
<epr pos="390" type="2" value="0">Extr.2 Z-offset [steps]</epr>
<epr pos="339" type="1" value="1">Extr.2 temp. stabilize time [s]</epr>
<epr pos="350" type="1" value="150">Extr.2 temp. for retraction when heating [C]</epr>
<epr pos="352" type="1" value="0">Extr.2 distance to retract when heating [mm]</epr>
<epr pos="354" type="0" value="255">Extr.2 extruder cooler speed [0-255]</epr>

Sorry for the long, detailed and potentially frustrating question. I'm really new to this.
Edit: To be more comprehensive, I'm including pictures of the controller boards.

Also, I've traced the printer down to a Taiwanese manufacturer: http://d-force.tw/
There are a few parts available: Hot-end PCB, Main controller board & Servo motor for calibration (Z-probe).
I haven't been able to find the other board (with the HRD12008 SMPS on it and placed just beside the main controller board), yet.
Does this change things? If yes then how?
I'm going ahead with burning a new firmware on the current board only because changing the board and shield combo seems too complicated to me. Is it though?
Comment: @Greenonline thank you so much :) The printer does have a z-probe. I've edited my question. Please let me know how it changes things.
Comment: It might be worth just *restating* the make and model of your printer, in *this* question, to save people having to click the link to your previous question :-)
Comment: @Greenonline please have a look at the firmware downloaded from repetier website. Its asking for pins used for z-probe etc while compiling. The link is: https://drive.google.com/drive/folders/0Bwypz0ZN4X9RUXBhcjBRVUVDTWM?usp=sharing
Comment: @Greenonline sure. I too agree that these questions have been branching out a lot. As soon as I get enough clarity regarding firmware variables, calibration and controller boards I will consolidate all info contained in the comments of those respective questions. I've asked a new question here: https://3dprinting.stackexchange.com/questions/4213/building-new-repetier-firmware-for-a-delta-printer-d-force
Answer: Each of the settings have informative comments written just before the setting's #define, so reading those can point you in the right direction - if the required value doesn't jump out at you from your EEPROM settings.
Taking an educated guess (and I could be wrong), and after looking at the comments, I would imagine that:

General and Dimensions:

KILL_METHOD. From Repetier firmware configuration questions (prusa mendel)

I would select the second kill method since it allows to continue with your printer after a crash.

So, you want to have
#define KILL_METHOD 1

No idea, at the moment
You can either measure the height the carriage is from the floor, when the rod(s) is(are) horizontal, or just use the default 15 to be safe - it is probably best to double check this and physically measure it, to prevent any damage:
// Margin (mm) to avoid above tower minimum (xMin xMinsteps)
// If your printer can put its carriage low enough the rod is horizontal without hitting the floor
// set this to zero. Otherwise, measure how high the carriage is from horizontal rod
// Also, movement speeds are 10x to 20x cartesian speeds at tower bottom.
// You may need to leave a few mm for safety.
// Hitting floor at high speed can damage your printer (motors, drives, etc)
// THIS MAY NEED UPDATING IF THE HOT END HEIGHT CHANGES!
#define DELTA_FLOOR_SAFETY_MARGIN_MM 15

DELTA_MAX_RADIUS use Max printable radius [mm].
The values you have for Alpha A(210), Alpha B(330) & Alpha C(90) each, would be for:
#define DELTA_ALPHA_A 210
#define DELTA_ALPHA_B 330
#define DELTA_ALPHA_C 90

The correction radii should be 0 and are the values you have for Delta Radius A(0), Delta Radius B(0) & Delta Radius C(0):
/** Correct radius by this value for each column.
    Perfect builds have 0 everywhere. */
#define DELTA_RADIUS_CORRECTION_A 0
#define DELTA_RADIUS_CORRECTION_B 0
#define DELTA_RADIUS_CORRECTION_C 0

Likewise, given your EEPROM settings that you have listed the values you have for Corr. diagonal A[mm], Corr. diagonal B[mm] & Corr. diagonal C[mm]:
/** Correction of the default diagonal size. Value gets added.*/
#define DELTA_DIAGONAL_CORRECTION_A 0
#define DELTA_DIAGONAL_CORRECTION_B 0
#define DELTA_DIAGONAL_CORRECTION_C 0

Z-correction (distortion correction)

DISTORTION_START_DEGRADE - Initially, I would leave this at default. You can always tweak it at a later stage.
/** z distortion degrades to 0 from this height on. You should start after the first layer to get
best bonding with surface. */
#define DISTORTION_START_DEGRADE 0.5

DISTORTION_END_HEIGHT - Initially, I would leave this at default. You can always tweak it at a later stage.
/** z distortion correction gets down to 0 at this height. */
#define DISTORTION_END_HEIGHT 1.5

DISTORTION_CORRECTION_R - Initially, I would leave this at default. You can always tweak it at a later stage.
/* For delta printers you simply define the measured radius around origin */
#define DISTORTION_CORRECTION_R       80

DISTORTION_UPDATE_FREQUENCY - For the moment, I would leave this at default. As the comments remark, this is computationally intensive, and will use a lot of processing power - power that you want to keep for controlling the motors. SO, it is best to not make this frequency too high.
/** Correction computation is not a cheap operation and changes are only small. So it
is not necessary to update it for every sub-line computed. For example lets take DELTA_SEGMENTS_PER_SECOND_PRINT = 150
and fastest print speed 100 mm/s. So we have a maximum segment length of 100/150 = 0.66 mm.
Now lats say our point field is 200 x 200 mm with 9 x 9 points. So between 2 points we have
200 / (9-1) = 25 mm. So we need at least 25 / 0.66 = 37 lines to move to the next measuring
point. So updating correction every 15 calls gives us at least 2 updates between the
measured points.
NOTE: Explicit z changes will always trigger an update!
*/
#define DISTORTION_UPDATE_FREQUENCY   15

Stepper

ENABLE_BACKLASH_COMPENSATION - As stated, it is rarely needed, so leave it set to 0
/* If you have a backlash in both z-directions, you can use this. For most printer, the bed will be pushed down by it's
own weight, so this is nearly never needed. */
#define ENABLE_BACKLASH_COMPENSATION 0

ALLOW_QUADSTEPPING - Do you need high frequencies? This could be a case of leaving set to the default of 1, and if you experience stalling then set to 0 to see if it cures the stalling
/** If you need frequencies off more then 30000 you definitely need to enable this. If you have only 1/8 stepping
enabling this may cause to stall your moves when 20000Hz is reached.
*/
#define ALLOW_QUADSTEPPING 1

Endstops

ENDSTOP_PULLUP_X_MIN/ENDSTOP_X_MIN_INVERTING - these are relatively easy.  From the comment for ENDSTOP_X_MIN_INVERTING
/* By default all endstops are pulled up to HIGH. You need a pull-up if you
use a mechanical endstop connected with GND. Set value to false for no pull-up
on this endstop.
*/

A pullup refers to a pull-up resistor. This is, in this case, a piece of circuitry in the MicroController Unit (MCU) (i.e. the Arduino chip[ATmega 2560] on the controller board. This #define allows you to enable, or disable, it for each input connected to an endstop. Basically, they stop short circuits between the power supply and ground - they do more than that but... You probably need the MAX endstops enabled, where you actually have an endstop. If there are no MIN endstops, i.e. at the bottom of the rails, then these can be set to false.
#define ENDSTOP_PULLUP_X_MIN false
#define ENDSTOP_PULLUP_Y_MIN false
#define ENDSTOP_PULLUP_Z_MIN false
#define ENDSTOP_PULLUP_X_MAX true
#define ENDSTOP_PULLUP_Y_MAX true
#define ENDSTOP_PULLUP_Z_MAX true

ENDSTOP_X_MIN_INVERTING this merely allows you to invert the input from the endstop. For example, if the endstop is triggered by a vertical carriage, then the switch will "close". If, instead, the code is actually looking for an "open" switch, rather than a "closed" switch, when the endstop switch is being triggered by the vertical carriage hitting it, then you simply need to invert it.
//set to true to invert the logic of the endstops
#define ENDSTOP_X_MIN_INVERTING true
#define ENDSTOP_Y_MIN_INVERTING true
#define ENDSTOP_Z_MIN_INVERTING true
#define ENDSTOP_X_MAX_INVERTING false
#define ENDSTOP_Y_MAX_INVERTING false
#define ENDSTOP_Z_MAX_INVERTING false

Fused Filament Fabrication

EXTRUDER_SWITCH_XY_SPEED - Probably best to leave as default, 100, and tweak later, if need be
/* Speed in mm/s for extruder moves fom internal commands, e.g. switching extruder. */
#define EXTRUDER_SWITCH_XY_SPEED 100

With respect to the temperature sensor settings on the extruder (read: hotend), from Repetier-Firmware Documentation:

#define EXT0_TEMPSENSOR_TYPE 5

What temperature sensor are you using in the extruder. The configuration file lists possible values
  and meanings.
#define EXT0_TEMPSENSOR_PIN 0

This parameter is tricky and often causes wrong configurations. For historical reasons it is named PIN
  but it IS NOT A PIN NUMBER. It is the position in an array of analog
  input sources. In this array, the real pin number is stored. In 99.9%
  0 is the correct answer here.
#define EXT0_HEATER_PIN HEATER_0_PIN

Which pin enables the heater block. It works with any pin. PWM capability is not required to use
  PID on an output.

For EXT0_TEMPSENSOR_TYPE, the temperature sensor is "buried' inside the hotend heater block, and as such it is probably not going to be easy, nor desirable, to remove and examine - although it is certainly possible to do so, if you feel up to the job. If could be just a question of trial-and-error. You have eight, or so, to choose from. However, the 100k thermistor is one of the most common types, and so 1 would seem like a good setting to choose, initially:
// What type of sensor is used?
// 0 is no thermistor/temperature control
// 1 is 100k thermistor (Epcos B57560G0107F000 - RepRap-Fab.org and many other)
// 2 is 200k thermistor
// 3 is mendel-parts thermistor (EPCOS G550)
// 4 is 10k thermistor
// 8 is ATC Semitec 104GT-2
// 12 is 100k RS thermistor 198-961
// 13 is PT100 for E3D/Ultimaker
// 14 is 100K NTC 3950
// 5 is userdefined thermistor table 0
// 6 is userdefined thermistor table 1
// 7 is userdefined thermistor table 2
// 50 is userdefined thermistor table 0 for PTC thermistors
// 51 is userdefined thermistor table 0 for PTC thermistors
// 52 is userdefined thermistor table 0 for PTC thermistors
// 60 is AD8494, AD8495, AD8496 or AD8497 (5mV/degC and 1/4 the price of AD595 but only MSOT_08 package)
// 61 is AD8494, AD8495, AD8496 or AD8497 (5mV/degC and 1.25 Vref offset like adafruit breakout)
// 97 Generic thermistor table 1
// 98 Generic thermistor table 2
// 99 Generic thermistor table 3
// 100 is AD595
// 101 is MAX6675
// 102 is MAX31855
#define EXT0_TEMPSENSOR_TYPE 1

As the Repetier documentation states, in 99.9% of the cases, for EXT0_TEMPSENSOR_PIN a value of 0 will probably work. If it does not, then you may need to change this to some other value.
For EXT0_HEATER_PIN HEATER_0_PIN, just follow the wiring of your printer, and see which pin the heater is connected to.

Where and how to change the settings
You are probably aware of this already, but in case you aren't...
Once you have downloaded Repetier-Firmware-master.zip from Github.com: repetier/Repetier-Firmware, and unzipped it, then you will need to edit the files in Configuration.h in the src/ArduinoAVR/Repetier directory. Note that the ArduinoAVR directory is used for the Arduino Mega 2560 board, and its derivatives.
Open Repetier.ino in the Arduino IDE, and edit Configuration.h in the Arduino IDE. You could also edit Configuration.h in your favourite plain text editor, if need be, but it is probably easier, and simpler to do everything in the Arduino IDE.
Once you have edited the settings that you require, as I described in Help with Repetier firmware (probably locked and licensed), compile and upload the firmware to your board. Then run a print. If something seems to be incorrectly set, stop the print. Then re-tweak your settings ad compile and upload again, and then run another test print. Ad infinitum...
After a few iterations, you should be quite comfortable with this process, and end up with a well calibrated printer.


Are Any Badges "Bad"?

Question: No, I don't want an argument on this. I'm wondering if (hopefully from a site admin/moderator/high rep user) if any badges are "bad". For example, the "tumbleweed" badge almost seems bad because it means you probably didn't ask your question well.
So, are any of the badges bad or are they all a "good" accomplishment?
Comment: Tumbleweed is not necessarily an indicator of a bad question, just a very localized one (i.e. the user has already provided so much detail that 1-few people know about that specific thing (resulting in low views), and 2-no one has to comment asking for more details).
Answer: "Badness" is ultimately a matter of opinion. FWIW, every time someone makes a request for a new badge for some negative behavior, it's downvoted to oblivion in short order with the note "badges exist to promote good behaviors." You can check some out at the lowest voted <code>[badge-request]</code> posts page.
Tumbleweed is an anomaly, it's kind of a "sorry nobody on our site could help you, have a consolation prize" badge. The fact that it goes to some bad askers is an unfortunate side-effect.
Comment: I just saw FWIW on another comment for the first time and off the top of my head could not figure out what it stood for.  I figured it out now, but it might be a little confusing for others.
Comment: Funny you should say that; I generally avoid abbreviations, but made an exception for FWIW because it's so well-known and easy to "reverse-engineer" (or so I thought). Thanks for pointing it out, I'll try to use it less in the future. @jzd
Comment: Yea, maybe I have just glazed over it in the past, but it stood out to me twice today.
Comment: @jzd: +1, I needed Googles help ... (@Popular: but that just a few seconds ...)
Comment: @jzd, hahaha, I think the other one you saw was also written by me (you answered a question of mine on SO that day).
Comment: I mostly need to look up stuff like that, since I'm not a native speaker. FYI ;-)
Comment: I had to look it up simply because, since it didn't appear to change the meaning of the sentence, my attempts to infer the meaning through context weren't doing as well as usual. :P

Are Any Badges "Bad"?


Can hood time in a glider be logged as simulated instrument time for FAA IR purposes?

Question: I need to build my simulated instrument time toward IR. Can flying under the hood in a glider (with an instructor/safety pilot...) be legally counted as simulated instrument time in the same way would be the case had it been an ASEL?
Comment: Curious as to what country you live in, and what instruments are in the glider.  My understanding is that actual cloud flying in gliders is still fairly common in Great Britain, even with no attitude indicator.  (So, "partial panel"-- turn rate indicator as only gyro instrument.)  This sort of thing used to be widely done all over Europe.  Don't forget to bring your parachute!
Comment: Oops never mind you said FAA.  Still curious about what instruments are in glider.
Answer: In the US, yes. According to the FARs you only need to have three hours in an airplane in preparation for the flight test and you must fly the cross country in an airplane so that's probably another 3 hours.
It looks like you can log hours under the hood in a glider, but it would have to be with an airplane CFII. However, I don't know that you would be able to train in any of the areas of operation except for (4) Flight by reference to instruments; so it probably wouldn't be worth your time. I don't know how you would fly an approach or fly a course by reference to navigation systems.
So as a practical matter, the answer is no.

§61.65   Instrument rating requirements.
(c) Flight proficiency. A person who applies for an instrument rating
  must receive and log training from an authorized instructor in an
  aircraft, or in a full flight simulator or flight training device, in accordance with paragraph (g) of this section, that includes the
  following areas of operation:
(1) Preflight preparation;
(2) Preflight procedures;
(3) Air traffic control clearances and procedures;
(4) Flight by reference to instruments;
(5) Navigation systems;
(6) Instrument approach procedures;
(7) Emergency operations; and
(8) Postflight procedures.

As an aside, I used to rent out my Cherokee to helicopter commercial students who needed instrument training

(i) Five hours on the control and maneuvering of a helicopter solely
  by reference to instruments using a view-limiting device including
  attitude instrument flying, partial panel skills, recovery from
  unusual flight attitudes, and intercepting and tracking navigational
  systems. This aeronautical experience may be performed in an aircraft,
  full flight simulator, flight training device, or an aviation training
  device;
Comment: Actually, in my case I became quite proficient in nearly all of the required skills by simply using a flight simulator with simulated ATC (pilotedge) so that I mostly need to build the time just as a formality.
Comment: @GJ Agreeed. Simulators are great for practicing your scan, learning to multitask, and reading approaches. I have way more sim time than hood time.


What is difference between leave one subject out and leave one out cross validation

Question: What is the difference between leave one subject out cv and leave one out cross validation (loocv)? are they same or different?. I have images of 24 subject and according to literature, leave one subject out is best cross validation for pain expression detection because  of its subjective nature.
is there any function for leave one subject out cv in sklearn like loocv? or I have to manually hold out one subjects images  (one subject out of 23) and train for rest 23 subjects? is it right approach ?
Answer: Leave one out subject makes it sure that you don't have subject bias.
The fact that you have the same subject in your training and your testing datasets will make the model know more about your subject than it should. With a brand new subject, the model will probably perform poorly because it never trained on the subject before.
There is no such tool available in sklearn, as it's very easy to build your own if the subject id is a column in your dataset.
Comment: I'm not a sklearn user, but if its definition of "leave out" doesn't entail leaving it "out" of the training set, then I'm unpleasantly surprised.
Comment: When sklearn splits the dataset, of course the test dataset is not in the training dataset. It's just that there is no leave ONE out, there are of course ways of doing cross validation, as this is more complex that LOO which is less than a one liner.


Is there a way to say "download" and "upload" in Latin?

Question: I checked neolatinlexicon and Google and I couldn't find anything
Answer: One possible set of words that would make sense for Latin could be to use importare and exportare:

importare: to bring, carry, or convey into, to bring in from abroad, to import
exportare: to bear or carry out, to bring out, convey away, export

Both of these are classical words, and the development in meaning is easy enough to tease out. If you really think about it, importing/exporting e.g. an image from an image editing software is really loading it/unloading it, getting that same root as upload/download. Moreover, it will allow for puns on/developments of porta/portus.
You'll not likely find a true word for it without resorting to calques. Even Germans often resort to using Download instead of a calque (for the noun, at least, don't know about the frequency of downloaden). I think it's because the English terms, as invented words (the original meaning of "download" is only from 1977 and changed as computing evolved), captured both a basic action and a metaphorical one, visualizing "cyberspace" directionally, thus the "up" and "down" prefix. But I think for Latin, in and ex work equally as well.
Answer: Traupman gives ex rete prehendere, and ex rete expromere. I note that ex rete prehendere is findable with a Google search, including some hits to Stack Exchange.
Answer: Maybe I would assign new meanings to verbs derived from verbs mittō ("to send") or ferō ("to bear, carry") with prefixes super- and sub-:
supermittō: "to upload"
superferō: "to upload"
summittō: "to download"
sufferō: "to download"
Compare verbs trānsmittō ("to transmit, send, carry, or convey across, over or through") and trānsferō ("to bear, carry or bring across or over; transport, transfer, convey over").
Comment: If only "submit" wasn't associated with the meaning "upload" in English... I think using "summitto" for "to download" can easily lead to a confusion.
Comment: @FlatAssembler
I added alternative idea with *ferō*. Let's suffer more :) .
Comment: @FlatAssembler One issue with that though is that Latin can easily be confused with English already. Think about the meanings of *sententia* or the difference between *opportunitas* and *occasio*. There's no good reason to let English dictate what the Latin ought to be.


Are there any rest areas in Dubai's Terminal 3?

Question: I am travelling to Melbourne with Emirates Airlines on 1st November 2017. I have a 3-hour layover in Terminal 3. Are there any rest areas where I could sit or lie down?
Answer: First of all, 3 hours is trivial to spend in Terminal 3; this is because you have a significant walk from the airbridge to the transit area; and depending on when you land, you may have a long wait at the security screening area.
If you are arriving at gate A, and departing on gates B,C,D or F - you'll have to take the train to the appropriate transit lounge area - and that can easily soak up 15 - 20 minutes (if there is a crowd).
Having said that, there are rest areas (permanently reclined seating), plenty of lounges that you may access, and even a dedicated quiet area - however, from my personal experience 3 hours goes by so fast that by the time you reach the rest area, you'll find that you have to start your journey towards your gate, which may be a train ride away.
The way the terminal is designed think of it like a three lane hall.
The middle lane is the shopping area, left and right lanes are for the gates, and at the end of the three lane corridor you have additional gates.
Then there is the main concourse area (where is the large waterfall and the giant glass elevators) this is where everyone enters the transit area.
The rest areas you'll find at the gates (either on the left, right or at the end of the corridor), where you'll get (permanently fixed, but reclined) seating. For further relaxation - there is a permanent quiet area (look for signs), and of course there is the airside hotel, spa(s) (yes, more than one) and even massage parlors and of course various transit lounges.
However, again, I caution against planning for a quick nap - 3 hours is nothing for a T3 transfer.
Answer: The generic answer to "Are there any rest areas where I could [...] lie down?" is always: check Sleeping in airports. It will list the places where you can sleep -- not many at this airport -- and things to do.
Answer: Terminal 3 is dedicated for use by your carrier, Emirates Airline, and has a number of lounges available to its passengers. Serving Emirates and Qantas, and said to be the largest terminal in the world, it has dozens of services and amenities, including rest areas, shops, restaurants, and spas (three of them!). Before your arrival in Dubai, you may want to consult the terminal map so that you can navigate your way more easily during your brief, 3-hour layover.


Is it possible to survive a plane crash on water?

Question: Is a scenario like the one in LOST possible? Is there a possibility of finding a significant number of survivors from a plane crash in the sea? Is there evidence of anything like this having ever happened in our world's history?
Comment: Wikipedia has a list of incidents where planes landed on water, many of these had survivors - http://en.wikipedia.org/wiki/Water_landing
Comment: I think if you're in a plane, and the plane is in the water, and it isn't a seaplane, it's a crash.
Comment: Start by defining what you mean by "crash". The word can imply a wide variety things from not-as-designed landings (often very survivable) through "controlled flight into terrain" and came-apart-in-mid-air scenarios. Then make sure that you are comparing apples to apples.
Answer: There were 50 survivors of ET Flight 961 and all 155 survived US Flight 1549, but those were controlled (well-controlled in the latter case) landings near land.
Comment: @djeidot -- and now he deleted his comment too.
Comment: @NateEldredge -- thanks, I got ET wrong initially too.
Comment: And now he deleted the sentence he didn't like.
Answer: This question actually has two parts, one obvious one is if it's possible have survivors after plane is ditched into the sea. Wikipedia provides dozens of referenced examples of such a cases, two prominent ones are already mentioned in Malvolio's answer.
Other part is "LOST" scenario is possible, which I understand as in passengers surviving but disappearing without a trace. This is highly improbable, due ICAO SARPs requirements for ELT (Emergency Locator Transmitters) on aircraft itself and on rescue equipment such as rafts. These ELTs operate as part of Cospas-Sarsat system. The only feasible scenario where none of the ELTs would be functioning, is aircraft wreck sinking into deep sea, dragging all of ELT equipped survival equipment to the bottom with it. In which scenario chances for survivors are practically nil.
Comment: It _used_ to be highly improbable.  Now I'm seeing rumors that the Malaysian flight might be as far away as Pakistan, so I'm downgrading it to "very improbable".
Comment: @Malvolio: I'm referring to scenario when crash occurred at sea. Besides, it doesn't matter. If it occurred over land, crash so hard as to destroy all ELTs would have to be also hard enough to kill everybody on board. ELTs are designed to survive crash.
Comment: If the black boxes are so indestructible, why don't they make the whole airplane out of the same stuff? Try the veal.


dc offset in a miller integrator

Question: I simulated a miller integrator circuit on multisim online. When I did so I made sure that dc offset in the op amp and the source is zero and also bias and offset currents are zero. But in output to a sine signal (ac) input, the output cosine signal has a negative dc offset. What is causing this offset?
Here is the circuit simulated:

And here is the input and output waveform:
Comment: The answer is staring you in the face ! What are the voltages at t = 0, look at the graph. Both waves start at 0 V because that is the starting point the simulator uses. At this point the capacitor has no charge. Give it an initial condition of 10 mV and the offset will be gone.
Comment: Lack of ground reference?
Comment: The choice to start the integration makes a lot of difference. The circuit is working like the math would. \$\int^{t_2}_{t_1} A\cdot sin(x)\:\textrm{d}x=A\cdot\left[cos(t_1)-cos(t_2)\right]\$. If you choose \$t_1=0\$ then the answer is always \$A-A\cdot cos(t_2)\$ and since \$cos(t_2)\$ can't be larger than 1, the integral is always positive or zero. Cool that an electronic circuit can obey the results expected from the math.
Answer: There's no offset. It works exactly as it should work. Your integrator charges at the positive half cycle of your V1 and discharges back at the negative half cycle.  this is the ideal operation.
In practice the integrator drifts due the leakage currents or opamp offset voltage. It can get stucked to max or min output voltage limit or it can gradually forget the starting point and operate as you probably waited. (= zero average due the leak resistance over the capacitor)
In practical integrator circuits there exists a reset switch or an inserted resistance in parallel  with C1.
ADDENDUM: Imagine you have a full glass of water. Take a straw and start to soak. The surface of the water sinks. Spit every drop back. The surface returns exactly to its initial position if you do not add anything of your own and do not forget to spit something back. That's a hydromechanical equivalent process for the behaviour of your circuit.

dc offset in a miller integrator


Behaviour of conductor ideal

Question: Let $f : A \to B$ be a homomorphism of finitely generated $k$-algebras, where $k$ is a field.  Let $J_A$ and $J_B$ denote the conductor ideals of $A$ and $B$ respectively for the corresponding normalizations in the quotient fields (assume that $A, B$ are domains).  Is it true that $f(J_A) \subseteq J_B$ ?  What is the relationship between $f^{-1}(J_B)$ and $J_A$ ?
Answer: There is no strong relations between $J_A$ and $J_B$ if you don't have some condition on $A\to B$.
First, it is not true that $f(J_A)\subseteq J_B$: just take $A$ integrally closed and $B$ not integrally closed. Then $1\in J_A$ but $1=f(1)\notin J_B$.
Second, suppose $B$ is the integral closure of $A$ and $B\ne A$. Then $J_B=B$ and $J_B$ is not contained in $f(J_A)B$.

Behaviour of conductor ideal


Disable "ondemand" CPU scaling daemon

Question: I have a server that, as of the upgrade to 10.04, is now running the "ondemand" CPU scaling daemon.  Why would it automatically install this?  I don't want my server saving power at the expense of performance.
Comment: You're mistaking the ondemand governor for the powersave one.
Comment: Agreed with Leon.  Ondemand speeds up if there's something to do and slows down if it's idling.  It does not restrict the CPU's ability to change speeds, but rather takes advantage of it.
Comment: Possible Duplicate http://askubuntu.com/questions/285434/is-there-a-power-saving-application-similar-to-jupiter/285681#285681
Comment: It increases response times on a mostly idle server.
Answer: Ubuntu prior to 18.04
Instead of disabling execution of the /etc/init.d/ondemand (as suggested by George) script you should use the this command
sudo update-rc.d ondemand disable

To make the init system not start the script, this is the recognized way of doing it! Disabling the exec permission (sudo chmod -x /etc/init.d/ondemand) might be overwritten if the package is updated.
Ubuntu 18.04+
Ubuntu relocated this script to ondemand.service which execute /lib/systemd/set-cpufreq; use this command to disable the service
~$ sudo systemctl disable ondemand
Removed /etc/systemd/system/multi-user.target.wants/ondemand.service.

Comment: If I do  : sudo update-rc.d other_governor enable , will it set a permanent desired governor ?
Comment: If anyone is wondering if there is a performance difference:

I just did a stress test on my MongoDB node (non-cloud bare metal) and simply by shifting the Intel CPU from power saving -> performance, the number of transactions per second that the node is capable of processing went from about 1000 /s to 5500 /s.
Answer: Frequency scaling isn't static. As soon as there is work to do, the CPU hops into action, P states boost up, and everything flies.
It's enabled because it's widely seen as a good thing. Saves you energy (good for your wallet and the environment). Keeps heat down (so important in a server room). And it's pretty unnoticeable.
Moreover on modern Intel chips, if you have scaling on you can use "turbo boost" where one core will run at higher-than-stock speeds for a time. This is very useful for spikes of single-threaded work. Without scaling enabled, you don't get this.
Comment: How long does it take ondemand to scale up on a P4 Xeon?
Comment: Came across this old answer and while I agree with Oli, there are specific user cases where you would want to disable CPU scaling - Audio recording for example. Unless you have a specific need, leave it at ondemand
Comment: By chance is there a way to know which process is constantly changing min/max values of frequency scaling? It always changes and I don't know why. see http://askubuntu.com/questions/800797/how-to-enable-turbo-boost
Answer: Set all CPUs to performance governor:
for GOVERNOR in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor; \
do \
    echo "performance" | sudo tee $GOVERNOR; \
done

All supported governors by Linux kernel:

performance Run the CPU at the maximum frequency.
powersave Run the CPU at the minimum frequency.
userspace Run the CPU at user specified frequencies.
ondemand Scales the frequency dynamically according to current load. Jumps to the highest frequency and then possibly back off as the idle time increases.
conservative Scales the frequency dynamically according to current load. Scales the frequency more gradually than ondemand.
schedutil Scheduler-driven CPU frequency selection

See https://www.kernel.org/doc/Documentation/cpu-freq/governors.txt
Comment: Note, `sudo echo > ...` doesn't do what you expect: http://askubuntu.com/q/230476/158442
Answer: You could install the rcconf debian tool:
sudo apt-get install rcconf

then disable the "ondemand" service from there.
Comment: I can't find any deprecation warning about the rcconf tool: you are missing the point and provided a completely wrong URL.

I didn't mean Arch's way of configuring rc scripts, but rather [the debian tool](http://manpages.ubuntu.com/manpages/natty/man8/rcconf.8.html) and that looks alive and well.
Comment: Thanks for pointing it out and supplying a helpful link! (I deleted my initial and wrong comment)
Comment: Also edited the original response!
Answer: On some systems, the 'ondemand' governor is unfortunately broken.
This is the case for "Intel(R) Core(TM)2 Quad  CPU   Q9300  @ 2.50GHz" and kernel 2.6.32-42.
The kernel thinks it can set the frequency individually for each CPU while the hardware actually only allows setting the frequency on groups of several CPUs (e.g. CPU 0 and 1 together, and CPU 2 and 3 together).
You may find out that the kernel isn't aware of this by looking at the /sys/devices/system/cpu/cpu*/cpufreq/affected_cpus files which contain "0", "1", "2", "3" instead of "0 1", "0 1", "2 3", "2 3".
The visible effect of this missmatch is a single-threaded process that starts running full speed on one CPU (the 'ondemand' governor reacts fast), and then, after about 20 seconds (depends on setting details), looses some of its speed.
The reason is the OS, with the 'ondemand' governor, periodically reapplies low freqs on the idle CPUs, not expecting that it will also implicitly change the freq of our busy CPU. It's not even visible when you look at /sys/devices/system/cpu/cpu*/cpufreq/*cur_freq or /proc/cpuinfo, the OS is just not aware of it!
So, on these systems the solution is to switch back to the simple 'performance' governor.
PS: In my case, running the CPUs constantly at their full freq didn't change anything concerning fan noise. I suppose when a CPU is idling, a lower or higher frequency will not have much impact on its power usage.
Answer: To make all CPUs run at maximum performance continually on a Ubuntu desktop or server, run:
sudo chmod -x /etc/init.d/ondemand

at the shell prompt and enter your password.
This disables the shell script that makes all CPUs run at speed "OnDemand", making them default to full speed (Performance).  You will need to reboot for this to take effect.
I have only tested this in Ubuntu Jaunty 9.04, but it should work and not cause any problems on any version of Ubuntu.
I think the Ubuntu defaults are strange for this.  A desktop or server should run at full speed, in my opinion.
Regards,
George
Comment: I don't think it's strange. Whilst certainly mobile is the most critical scenario for power-saving, reducing power usage also means less fan noise in a desktop scenario, and less heat to deal with in a server room. Running constantly at maximum speed is a bit of a waste, only really necessary for rare cases where `ondemand` gets it wrong.
Comment: @bobince - You are probably right, but for a desktop I have noticed that OnDemand gives a sluggish response compared to Performance, and I think the computer can still sleep properly with the above change.  It should be an option in System/Administration or System/Preferences.
Comment: Right, the only place this makes sense is on laptops where charge-time is shortened and battery-time extended by scaling the CPU.
Comment: saving the environment, anyone??
Answer: I have a new processor AMD Athlon II X4 631 (Fusion processor for socket FM1) and it doesn't save any energy whatsoever (I looked it with energy meter)! I don't have a turbo core, so I don't need ondemand setting. Most new processors save enery by themselves.
When benchmarking, there is a little difference, in the range on 1-2%, when comparing ondemand and performance setting.
Comment: Welcome to AskUbuntu! You may want to back up your statements with full statistics/research as your answer could be misunderstood as an opinion rather than a researched answer.
Comment: This is also wrong, Apple's getting in trouble this week for [slowing down devices to save power](https://www.npr.org/sections/thetwo-way/2017/12/21/572538593/apple-says-it-slows-older-iphones-to-save-their-battery-life)
Answer: This is old, but since no one mentioned it, and for the sake of completeness, I will add that the argument how CPU which runs on the maximum speed will waste power, produce heat, fan noise etc. is WRONG.
Almost all modern CPUs, especially Desktop / Server CPUs, will enter deep sleep mode when idle (google race to idle.).
Voltage scaling will probably save more power, so on laptops this could increase running time a little, but on desktop and servers running performance governor will be fine for most of 'normal' users (who don't run server farms or similar.).
I use performance gov with my i7-2600k and the CPU temperature is usually around 30 C.
Comment: This is just wrong too. Monitor cpu temps and change frequencies to see for yourself (unless your system doesn't implement it fully/correctly). See the Apple link too, sounds like regular frequency/speed scaling
Comment: @Xen2050, to see what for yourself? Do you imply that CPU which runs at 70 degrees Celsius for 2 sec, might consume more power, than one which runs 5-6 sec at 60 Degrees, or something in that direction? It is not that simple as monitoring CPU temp in particular moment.
Comment: @Xen2050 your link points to iPhone, which is totally different arch or processors. I have indicated that voltage scaling in combo with particular governor could help on laptops for example, and mentioned desktop (Workstation), and server processors explicitly, but as a matter of fact what I was talking about exist even on phones too for years now (The situation is probably more complicated in this case. A proper governor might be required for MPU to utilize particular C/P state. properly). Anyway read one more time what I have typed, and google 'race to idle' and processor deep sleep modes.

Disable "ondemand" CPU scaling daemon


Why downloading updates in android ask wifi connection rather than mobile data?

Question: Why did downloading updates in android ask wifi connection rather than mobile data?
Answer: The size of update package is generally large so it by default uses only wifi rather than mobile data so that no money is deducted in case the mobile data is exhausted or there is no data plan.
In old devices
Go to setings --> About device --> software updates.
Here you disable the option download software updates via WiFi and enable , automatically download software updates or select manually update.
In new devices
If you're using a new device after clicking on check for updates ,you'll get a alert or popup showing what's the latest update, in most of the cases you will find a checkbox ticked against download using WiFi only, just disable the check box. If this is not the case then on the screen where you download the updates there should be three dots in upper right corner, you will be sure to find the option to change data usage preference there.


Does EMDR legitimately treat any condition?

Question: Are there any studies not funded by friends or beneficiaries of EMDR that prove it helps with a strong p-value?
Comment: What studies have you found which were "funded by friends or beneficiaries of EMDR"?
Comment: Seems a simple enough question to answer, although Chris points out a valid concern with the way your question is phrased.
Comment: @Chris I don't think that the OP was referencing any specific study, he was just looking for studies done by neutral third parties.
Answer: TLDR: EMDR seems to be equally efficacious to other therapies.
Davidson & Parker, (2001) conducted a meta-analysis.

Eye movement desensitization and reprocessing (EMDR), a controversial treatment suggested for posttraumatic stress disorder (PTSD) and other conditions, was evaluated in a meta-analysis of 34 studies that examined EMDR with a variety of populations and measures. Process and outcome measures were examined separately, and EMDR showed an effect on both when compared with no treatment and with therapies not using exposure to anxiety-provoking stimuli and in pre–post EMDR comparisons. However, no significant effect was found when EMDR was compared with other exposure techniques.

Rothbaum, Astin, & Marsteller, (2005). Looked at EMDR with Rape Victims.

This controlled study evaluated the relative efficacy of Prolonged Exposure (PE) and Eye Movement Desensitization and Reprocessing (EMDR) compared to a no‐treatment waitlist control (WAIT) in the treatment of PTSD in adult female rape victims (n = 74). Improvement in PTSD as assessed by blind independent assessors, depression, dissociation, and state anxiety was significantly greater in both the PE and EMDR group than the WAIT group (n = 20 completers per group). PE and EMDR did not differ significantly for change from baseline to either posttreatment or 6‐month follow‐up measurement for any quantitative scale.

Seidler, & Wagner, (2006) conducted another meta-analytic study.

The superiority of one treatment over the other could not be demonstrated. Trauma-focused CBT and EMDR tend to be equally efficacious. Differences between the two forms of treatment are probably not of clinical significance. While the data indicate that moderator variables influence treatment efficacy, we argue that because of the small number of original studies, little benefit is to be gained from a closer examination of these variables. Further research is needed within the framework of randomized controlled trials.

References
Davidson, P. R., & Parker, K. C. (2001). Eye movement desensitization and reprocessing (EMDR): A meta-analysis. Journal of consulting and clinical psychology, 69(2), 305.
DOI: 10.1037/0022-006X.69.2.305 PMID: 11393607Free PDF: https://pdfs.semanticscholar.org/d703/9ab57fabe1a3b0aee33bf558b95cf228700c.pdf
Rothbaum, B. O., Astin, M. C., & Marsteller, F. (2005). Prolonged exposure versus eye movement desensitization and reprocessing (EMDR) for PTSD rape victims. Journal of traumatic stress, 18(6), 607-616.DOI: 10.1002/jts.20069FREE PDF: https://pdfs.semanticscholar.org/d5cd/abbee19ef9886327fd77be0587e6826842d6.pdf
Seidler, G. H., & Wagner, F. E. (2006). Comparing the efficacy of EMDR and trauma-focused cognitive-behavioral therapy in the treatment of PTSD: a meta-analytic study. Psychological medicine, 36(11), 1515-1522.DOI: 10.1017/S0033291706007963
Comment: +1 However, what is the point of the double negation? "seems to not to show any more"... Just say (as they do in the abstract): "equally efficacious"


Can php be installed on a windows server?

Question: Can php be installed on a windows server?
Answer: Yes. Get the web platform installer.
http://www.iis.net/download on the left (Web PI).
It is like a package manager for IIS.
On IIS.NET you also ind a lot of nice add ons for PHP -fastcgi etc.
Answer: Yes, PHP most certainly can be installed on Windows Server. You can choose to install the FastCGI or ISAPI modules in IIS, or alternatively you can install another web server package within windows, such as Apache.


Can I exploit Windows kernel from user-mode application?

Question: In this document is detailed technique of exploiting Windows kernel. But writer is talking about accessing kernel memory & doing exploit from user-mode application at the same time. Can I do this from user-mode application, or do I need to do it from driver? Thanks.
Comment: I believe you don't need a driver, if you can code C or C++ or any low-level languages that has the capability to do this, you'd be set.
Keep in mind that messing with the windows kernel will raise AV's attention for your application, also, i don't believe using ntQuerySystemInformation nowadays and other API's that document shows will actually acomplish that, if you could elevate priviledges (i hope i didn't read wrong) with UAC on, you'd make some $..
Comment: @SomeNickName if UAC is in play you're already elevated - the application just doesn't get access to the full token directly. Its relatively easy to get the full token. It doesn't offer any protection at all.
Comment: @SteveS Are you saying it's easy to bypass UAC? "Unabling" all his purpose? which is when you try to elevate an application, it pop's up?
In short, getting admin priviledges without popup ?
Comment: @SomeNickName I'm saying its *possible* to bypass UAC, and its relatively easy, but does require some effort. UAC is not actually a security boundary. It offers some protection against simple bits of malicious code, but advanced attacks can and do bypass it.
Comment: I'm talking in terms of elevation, any attempt to elevate an application's priviledges to "admin" or higher should trigger UAC if enabled, i was asking if you can do that without triggering uac.
I've seen exploits and other "tweaks" or something, but i believe public one's are already patched, haven't tested any though, but i'm sure it's not that easy, otherwise everyone could do it... :/ and that would be sad lol.
Answer: You need admin rights to normally get code into the kernel, and code is usually executed by a driver. Code in user mode cannot by design execute in kernel, so you have to find a bypass vulnerability to get past the user-mode barrier. If you can find such a vulnerability you can execute from user mode.
Other attack vectors are to find an EOP vulnerability, elevate to admin, and install a malicious driver.
Answer: The document uses Windows API (NtQuerySystemInformation, NtOpenThreadToken ...) to have the pointer of Kernel Objects like _EPROCESS, _TOKEN, OBJECT_HEADER. This is done from User land.
Knowing the pointer address allows altering these object, but this can be done from the Kernel land only, for example by exploiting a Driver or a some Kernel API vulnerability that could allow for arbitrary write.


Logistic regression with binary dependent and independent variables

Question: Is it appropriate to do a logistic regression where both the dependent and independent variables are binary? for example the dependent variable is 0 and 1 and the predictors are contrast coded variables -1 and 1 ?
Answer: For, clarity: the term "binary" is usually reserved to 1 vs 0 coding only. More general word suitable for any 2-value coding is "dichotomous". Dichotomous predictors are of course welcome to logistic regression, like to linear regression, and, because they have only 2 values, it makes no difference whether to input them as factors or as covariates.
Answer: There is no reason not to do this, but two cautionary thoughts:

Keep careful track during the analysis of which is which. In large projects, it can be easy to get lost, and produce errant results.
If you choose to report regression estimates, rather than odds ratios, make your coding scheme clear in your report, so readers don't produce inaccurate ORs on their own assuming they were both coded 0,1.

May seem basic, but I've seen both problems make it into published papers.
Comment: So then it would also be appropriate to separate a datafile into 6 separate cases and run individual comparisons within each dataset with constrast coded predictors?
Comment: I'm honestly not sure what you're asking for this second bit. Can you clairify what you're hoping to accomplish?
Comment: I have a dataset with 3 between and 4 within subject conditions. I would like to test for each and every effect, but a single regression with all interactions miss a lot of information I'm interested in. Instead I would divide the data by condition into separate datasets and run focused logistic regressions on each datasets with contrast codes coding for the differences i'm interested in.
Comment: for even more info on how I code the contrast codes see here: http://stats.stackexchange.com/questions/14546/how-to-interpret-regression-coefficients-in-logistic-regression
Answer: Typically it helps interpretation if you code your predictors 0-1, but apart from that (and noting that it is not required), there is nothing wrong with this. There are some other (contingency-table based) approaches, but if I recall correctly, these turn out to be equivalent to (some form of) logistic regression.
So in short: I see no reason not to do this.
Comment: thanks! And if I have 3 contrast coded predictors and I code them all 0-1 then they won't be orthogonal. For example I have 4 categories and my three codes are L1: 1,-1,0,0 L2: 0,1,-1,0, L3:0,0,1,-1. is that an issue?
Comment: Your example L-matrix (L1,L2,L3) is the _repeated contrasts_ whereby each category is compared to the following category. Neither these contrast predictors are orthogonal nor they are binary (coded as 0-1). In fact, their values are .75 vs -.25 (1st variable), .5 vs -.5 (2nd variable), .25 vs -.75 (3rd variable)
Answer: In addition, if you have more than two predictors,  then it is more likely that there would be a problem of multi-collinearity even for logistic or multiple regression. However, there is no harm to use logistic regression with all binary variables (i.e., coded (0,1)).


How frequent is high sticking in Ice Hockey?

Question: Are there any statistics for how frequently a specific penalty occurs in Ice Hockey? (any League?) I am specifically interested in high sticks.
Answer: Looking at this stats page, it looks like high sticking accounts for ~10% of all minor penalties. From the same site, on average there are about 3 penalties per game per team, so you end up with 6 minors per game, so in 60% of games there is a high sticking minor.
Comment: Your information is great and to the point.  However (and someone do please correct me if my math has gone askew!!!), I don't think your conclusion of 60% is valid.  If you have 6 minors a game and 10% are due to high sticking, to determine the games that have high sticking, you'd do $1-(.9^6)$, so only ~47%.  It's because there's overlap, in that some games have 2+ high-sticking events, and so that uses up some of the high sticking games... see https://www.khanacademy.org/math/probability/binomial-probability-a2/binomial-probability-a2i/v/probability-of-making-2-shots-in-6-attempts)
Comment: That result could be further complicated yet since high sticking events may not be independent.  Statistics is a strange beast that (works against intuition often)[https://en.wikipedia.org/wiki/Monty_Hall_problem].  That said, it's not that big of an adjustment, and you're already working on rounded values.  So no big deal!  Good answer, +1 :-)


What is the origin of the term "Couch Potato"?

Question: I know the meaning of "couch potato" is a person living a mostly sedentary lifestyle who likes to watch TV while lying on the couch, but why potato?
Answer: Couch Potato was introduced by Robert D. Armstrong in the book The Official Couch Potato Handbook
From http://classic-web.archive.org/web/20080521102001/http://www.potatomuseum.com/exCouch.html
"Very few words have a birthday so precise, and so precisely known, as couch potato. It was on July 15, 1976, we are told, that couch potato came into being, uttered by Tom Iacino of Pasadena, California, during a telephone conversation. He was a member of a Southern California group humorously opposing the fads of exercise and healthy diet in favor of vegetating before the TV and eating junk food (1973). Because their lives centered on television--the boob tube (1966)--they called themselves boob tubers. Iacino apparently took the brilliant next step and substituted potato as a synonym for tuber. Thinking of where that potato sits to watch the tube, he came up with couch potato.
Comment: I'm fairly certain the term as around before this 1982 book, but can't find anything online to back that up. Anyone have a good dictionary of slang etymology?
Comment: @Neil Fein - I love Google Books, but they're not always as careful about adding metadata as one might wish.  For instance, if you scroll to the top of that book's entry, you'll see that the actual date of publication was... 1999.
Comment: @MT - Ah, you're right. (And I spotted this in another book: There's an issue of a business magazine that uses the term; GB says it's from 1940, but the cover is distinctly modern.)
Comment: @Neil Fein - I swear sometimes I don't know where they come up with the dates they list... there was a _TV Guide_ citation in the same search results, and the GB date was 1958 (the show listing was the _Tracey Ullman Show_, however, so it was sometime in the late '80s).  I thought at first that they might be using the magazine's founding date, but _TV Guide_ started in 1953, not 1958...
Comment: @MT_Head and @Neil: this is a well-known problem with Google Books. See this Language Log post: [Google Books: A Metadata Train Wreck](http://languagelog.ldc.upenn.edu/nll/?p=1701) or [this post](http://meta.english.stackexchange.com/questions/1196/google-ngrams-for-the-web-not-just-books/1198#1198) of Kosmonaut's on meta.
Comment: @MT_Head and @Neil: Sometimes GB just reads a date wrong—especially if it's small or in an unusual font. I've seen 1986 read as 1906, for example. Other times, absent a clear publication date, the first date scanned within a text is listed as the publication date. That said, I'm confused about the date debate on the [Couch Potato book](http://books.google.com/books?id=tWKCpSKjzZoC&printsec=frontcover&dq=couch+potato+handbook&hl=en&ei=GgfyTeq2KajL0QGeoc2GDA&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCoQ6AEwAA#v=snippet&q=copyright%201982&f=false), and the downvotes on this answer.
Comment: The downvotes aren't mine. This may not be am exhaustive, extensive answer, but neither is it wrong. (I posted a link to a book I thought was earlier, but accidentally deleted the comment, making this look all weird. Sorry about that!)
Comment: Nor mine... (!)
Comment: Piers Anthony turned it back around and mentioned in one of his books "Cathode Ray Tubers".
Answer: Etymonline says the usage was first recorded in 1979.
Google NGrams apparently backs this up, and yet shows an anomalous blip around the turn of the 20th century:

What to make of the 1900 bulge, I can't say.
"Potato" is used presumably because it's inert, shapeless and plump: like most people who spend their lives in front of the TV. It also has a similar sound to other expressions using a stressed modifier followed by "potato": hot potato, sweet potato, mashed potatoes, etc., so there was a sound to mimic to make it sound "right".
Comment: I found that same blip earlier, if you look at the details for [1900 - 1904](http://www.google.com/search?q=%22couch+potato%22&hl=en&safe=active&tbs=cdr:1,cd_min:1900,cd_max:1904&tbm=bks&sa=X&ei=e-_xTcOeO4yzrAfnuYD6Bw&ved=0CAQQhQE), it shows *No results found for "couch potato" Results for couch potato (without quotes)*. Is that normal in NGrams?
Comment: The OED also dates it from 1979, but the quotation (from the LA Times) "The Humboldt State Marching Lumberjacks‥and the Couch Potatoes who will be lying on couches watching television as they are towed toward the parade route." strongly suggests that this was a name, presumably a jokey reference to a phrase already in use.
Comment: @JoseK: I normally tread lightly with NGrams because of anomalies like this, and I hesitate to use it as a comparison tool at all, since the meanings of the compared expressions are hard to nail down.
Comment: The earlier blip [appears to be](http://www.google.com/search?q=%22couch+potato%22&btnG=Search+Books&tbm=bks&tbo=1#q=%22couch+potato%22&hl=en&sa=X&ei=gPrxTaH3IKLt0gGghImODA&ved=0CBkQpwUoBA&source=lnt&tbs=cdr:1%2Ccd_min%3A1%2F1%2F1890%2Ccd_max%3A12%2F31%2F1914&tbm=bks&fp=9608e099c2a108b9&biw=1280&bih=705) a date mis-scan of an issue of _The Savoy_ and a capture of _Couch_ and _Potato_ next to each other.
Comment: There a lot of words with a 1900 data,  it generally means the date was missing and the system defaults to 1900. 1904 was the base date on the old mac-os but that may be coincidence
Answer: OED
The Oxford English Dictionary says:

couch potato n.  [potato apparently punningly after (boob-)tuber   = television addict and vegetable tuber, but perhaps simply by association with vegetable n. 2] slang (orig. U.S.) a person who spends leisure time passively or idly sitting around, esp. watching television or videotapes.
1979   Los Angeles Times (California Record ed.) 28 Dec. iv. 1/6   The Humboldt State Marching Lumberjacks..and the Couch Potatoes who will be lying on couches watching television as they are towed toward the parade route.

NPDSUE
The New Partridge Dictionary of Slang and Unconventional English (2008) says:

couch potato noun a person who habitually idles, watching television. Possibly a pun on 'boob-tuber' (a television addict) and a 'potato' as a 'tuber'; it may also play on VEGETABLE (a person with an undemanding existence); the 'couch', of course, is where the potato is planted. One of the very few slang words or phrases where it is seemingly possible to trace the coining; in July 1976 a group of friends in California coined the term, which was first used in commerce in 1977 and then hit the big time with the Official Couch Potato Handbook (1983) US, 1976

ADS-L
Here's the origin according to posts made on the American Dialect Society mailing list.
First from Barry Popik:

COUCH POTATOES
OED has "couch potato" from 1979.
     USPTO records show it was trademarked by Robert Armstrong of Dixon, CA,
  with first use of July 15, 1976, and first use in commerce of April 20, 1977.

Larry Horn concurred:

Fer sher.
Robert was a fellow-traveller of R. Crumb and his Cheap Suit
  Serenaders, a somewhat funky string band.  They all holed up in a
  nice country house in Sonoma County at the time, and Robert lived off
  the royalties of "couch potato" and silk-screened T-shirts for a
  while back then.  Some of the T-shirts featured a laid-back spud qua
  couch potato, i.e. a "tuber".  Them was the days.

Finally from A. Allan:

The origin of "couch potato" is explained in detail in a book to be published
  in October by Houghton Mifflin:
"Predicting New Words: The Secrets of Their Success" by Allan Metcalf. Here
  is a pertinent excerpt:
. . . Here's how it chanced to happen, according to an illustrated history
  by two of the perpetrators themselves, "Elders" Jack Mingo and Robert
  Armstrong, in The Official Couch Potato Handbook (1983). The saga began in
  the 1960s with nine Southern Californians who got together on Thursday nights
  to watch Lost in Space. Calling themselves the "Lost in Space Club," they
  soon began meeting to watch other television shows as well. "One of them,"
  the story continues, "known only as 'The Hallidonian,' soon made the
  discovery that any day, any time was all right for prolonged, indiscriminate
  TV viewing."
Then, supposedly on July 15, 1976, another of the nine "Elders," Tom
  Iacino, uttered the term couch potato in making a phone call to The
  Hallidonian. The illustrated history depicts the moment: "Hi, Annie Jo--Can I
  speak to the 'couch potato'?" asks Iacino's telephone voice, to which Annie
  Jo responds "The wha?" while across the room the Hallidonian relaxes on his
  couch, watching The Flintstones. . .
Answer: It might have something to do with people being called a 'vegetable' when they are unconscious in a coma (in a vegetative state).
 Vegetables are inanimate objects. A potato is a vegetable, chosen for the phrase perhaps because of it's plump shape that would be associated with some who doesn't do any exercise and would likely be overweight.
Answer: Philo Farnsworth... is credited for inventing the television and once lived in Idaho which is famous for its potatoes. People who watch lots of television are often called couch potatoes. There could be some correlation between the term and the origin of the television.
http://en.wikipedia.org/wiki/Philo_Farnsworth
Comment: With out a single reference to back this up and the most tenuous of links, this hardly qualifies as an answer ;)
Answer: If you look at the MyOldRadio.com website, episode 304 of the Our Miss Brooks radio show (which aired August 28, 1955) is entitled "Couch Potato." I assume this is the actual title of the episode that the people who run the website got off of some sort of log for the show; but we all know what happens when one assumes something.
Comment: I listened to the episode (also titled "Moving Day") but unfortunately didn't hear any mention of *couch potato* but there is a couch from around 20 minutes and 26 minutes.
Answer: I always thought it was a reference to the random stray potato chips you sometimes find lodged in the couch cushions.  They are always found somewhere on/in the couch.....as are the people that watch tv all the time.
Comment: Oh that's clever. You know, it's not bad as theories go. Pity there aren't any references, but then again who doesn't eat something while watching the TV?


No Printers are detected when running the site outside of Visual Studio 2013 in IIS7

Question: I've built an application to print documents.
When running the application using Visual Studio - debugging mode I could receive the list of available printers using :
PrinterSettings.InstalledPrinters

and then , I select one of them to print the document using :
PrintDocument printDocument = new PrintDocument();
printDocument.PrinterSettings.PrinterName = "Fax" ; //or any other listed printer that is returned from the method above
printDocument.PrintPage += printDocument_PrintPage;
printDocument.Print();

void printDocument_PrintPage(object sender, PrintPageEventArgs e)
{
    e.Graphics.DrawRectangle(new Pen(Color.Red,10),new Rectangle(0,0,100,100));
}

This works inside of Visual Studio, but when I migrate it to IIS 7 root folder on the same computer, it gives an error "there's no printers installed"
Note: I still can get the same list of available printers when I deploy the application to the root folder, but when Print() method is called, the web application throws the error.
I am using the namespace System.Drawing.Printing
Update : I did check the System.Printing namespace  reference page, it also shows a box says :

"Classes within the System.Printing namespace are not
  supported for use within a Windows service or ASP.NET application or
  service."
Comment: Printers are a per-user account setting. I'm guessing that the application pool isn't running under your user account. Also, [System.Drawing.Printing Namespace](https://msdn.microsoft.com/en-us/library/system.drawing.printing(v=vs.110).aspx): "Classes within the System.Drawing.Printing namespace are not supported for use within a Windows service or ASP.NET application or service."
Comment: since I am able to get the available printers list , I don't think it is a user account settings issue , thank you for the link
Answer: I had the same issue, you could see in service how RPC (in services) is running (network service | local sytem) and put that in the application pool on IIS adance setting Identity.
I hope I could help!.


PTO - sick time vs personal time

Question: I am a nurse in a large hospital.  We are given non-specific PTO (paid time off).  My boss has been calling people after they have called in sick questioning if they are truly sick.  She is make people disclose details if they take "personal" time.  Then, she is calling those people on a day they were not scheduled to work and telling them they need to come in because they are short-staffed.  Can she legally  call employees and check up on them if they are sick?  Is it legal for her to ask about personal days?  Can she make a person come in on their day off?
Comment: I'm sorry, but this is a question asking for legal advice, which is specifically off topic here.  What I would suggest is contacting your ombudsman, HR, or a lawyer to discuss.  If you are a member of a union, they may be able to assist you also.
Comment: Check with HR but while this guy is an ass, he may be within his rights to take the actions he does (depending on the jurisdiction). However, it would quickly cause the company to have to deal with turnover, so even if legal, HR might not like it that he does this.  If illegal, you would spend alot of time (possibly years) and money to sue, so really it is better to let HR deal with it and if they won't then vote with your feet.
Comment: Of course it is unreasonable for a manager to call people on their PTO and demand they come in to work, but it would be a colossal waste of time to approach this as a legal matter. Most likely there is something which is propelling this manager to behave in this way. It seems like a reaction to some kind of real or perceived offense. If HR doesn't help (don't expect anything substantive), the most productive course of action if you intend to stay at your job long term is to find out what is _really_ the issue with this manager and address it in way she can understand.
Answer:
1) Can she call employees and check up on them if they are sick?

She can call whoever she wants to, but she is a fool if she starts asking personal information. Massive legal liability. If sick time is used, she can require a doctors note to return to work. If sick time has been exhausted, and the employee is not covered by FMLA (or equivalent law about granting leave in your country), the employee can be fired, but questions still cannot be asked. If the employee is covered by FMLA, questions still cannot be asked, but the doctor's note process is much more intensive.

2) Can she ask about personal days?

No, personal days are exactly that, personal. You are not required to say anything, and if she pushes at that, you can go to HR and she will probably be reamed.
Personal days may require approval before use, that depends on the guidelines your HR department has set forth. That approval should be purely schedule based. You might be asked for a short blurb for description, but you can literally just write "personal reasons".

3) Can she make a person come in on their day off?

The overwhelming odds are no. Even if the nature of your work is that you are on call, then you are on call, not enjoying a day off. There could be something in your contract that says you need to come in, but I highly doubt it.
Id take up all of these questions with your HR department, and get more information about what your specific HR guidelines are.
Comment: Perhaps edit your answer to point out the "FMLA or equivalent in your country"? :)  And describe the acryonym.  I can only guess what FMLA stands for :)
Comment: @JaneS: https://en.wikipedia.org/wiki/Family_and_Medical_Leave_Act_of_1993 (I also had  to look it up). I proposed an edit.
Comment: I agree with most of this answer.  However, the FMLA is country specific and we don't know where the OP resides.  Not all of us are in the US (including me :) )
Comment: Ah, yes, very true. I can only talk of my my experiences in the US.
Answer: Unfortunately; this will probably get closed due to asking for legal advice (but a rephrasing of the question could bring it back on topic).
Anyway, going back to your questions (and ignoring the legal aspect of it):

Can she call employees and check up on them if they are sick?

She can do whatever she wants.  Doesn't mean you have to answer the phone if she calls.

Can she ask about personal days?

She can do whatever she wants.  You can always reply with "It's a sensitive personal matter; I'd rather not discuss it with co-workers".  (repeat as necessary)

Can she make a person come in on their day off?

There's probably something in your employment contract that stipulates this; but if you don't pick up the phone, how's she going to make you come in?
Comment: I'd suggest finding out where you stand legally before taking this approach.  If you find out that she can do exactly what she is doing, then you could perhaps do this.  I would however ensure that she is not breaching some HR protocols.  It seems her behaviour is not entirely professional.

PTO - sick time vs personal time


Trouble with IMovie?

Question: My friend can get iMovie for free on his iPhone, but I can't. I still have to pay $4.99 for the app. I've asked 3 other friends about the app and all of them get it free. Why can't I get this app?
Comment: what is your iPhone model ? and is it on IOS8
Answer: Here is what Apple says:
Feb 3, 2015 - To qualify for these free apps, you need a device that was activated or purchased on or after September 1, 2013.
When you upgrade to iOS 8 on a qualifying device or buy a new device with iOS 8, you'll have access to these apps for free: iMovie

Trouble with IMovie?


Convert Theta ERC-20 to Theta Main Network

Question: As a test, I transferred one Theta ERC-20 token to my new Theta web wallet, and I see it there.  How do I now convert it to the main net Theta?
Answer: On another site, someone reported this:
Your actual theta tokens are in the wallet where your ERC20 tokens were at time of the deployment of the theta blockchain. You have to get the private key for that wallet and open it on the theta web wallet site to gain access to not just your theta but also your tfuel.
My response and results:
I would have never guessed I could logon to an old ETH wall from the Theta Wallet.
Worked great, much easier than I thought. I was guessing I would have to ask them to convert it.
My ERC-20 Theta tokens were on Exodus, and unfortunately Exodus has not added support yet for Theta.  In that wallet you are able to show your private/public key for Ethereum.
With that, I was able to logon to Theta wallet with my private key from Exodus and see my coins and TFuel, then I just transferred them to my newly created Theta wallet.
Comment: Ledger Nano used to support the Theta ERC20 token. Does it now also support the new non-ERC Theta token?
Comment: I don't know, don't use a Nano yet.