Do you need a current limiting resistor on an enable pin?

Question: I am using MCP16312-E/MS buck regulator and need the component to always be on. I am therefore connecting the enable pin to the Vin supply. Do you need a current limiting resistor? Whilst the resistor I have in series with the enable pin will limit the current, it will also 'take' all of the supply voltage so the voltage at the enable pin itself will be 0V? Is this correct? If so, what should be done instead?
Comment: Usually no for every IC I have used so far. What does the datasheet say?
Comment: (a) a current-limiting resistor is generally not necessary (b) 1 Megohm is far too large for a series current-limiting resistor.  (c) It is sometimes nice to have a series element during the development/prototyping stage of a project, which gives a place to disconnect EN from the supply and jumper it to either the ground rail (during troubleshooting) or to a digital control, if one finds that controlling it might be valuable after all
Comment: it's very likely that EN is a high impedance input and "essentially" zero currently will flow into the pin under any circumstances.
Answer: I absolutely agree with @DirkBruere - you should read the datasheet.

I read the datasheet and it says nothing

Let's see if that is true.
First, the very first picture in it has EN pin connected to Vin. This tells you that for "always ON" applications you don't need the resistor at all.

Second, in the Absolute Maximum Ratings you can see that maximum input voltage is 32V and EN pin can be 0.3V higher, i.e. 32.3V maximum. This confirms that you can connect EN pin directly to input voltage.

Third, in DC Characteristics you can see that maximum EN Input Leakage Current is 1 microampere at 5V. It won't be too much higher than that at higher input voltages.

1 uA current through 1 MOhm resistor allows you to calculate voltage drop on resistor. In this case 1uA * 1MOhm = 1V. So, if your input voltage is 5V then the voltage on EN pin would be 5V - 1V = 4V.
Finally, in the same table you look for EN input voltage characteristics, and find that EN Input Logic High minimum is 1.85V, so anything above it will switch device ON. Calculated above 4V voltage is certainly sufficient.  However depending on input capacitance the start-up time can be quite high. For this reason 1k-10k resistors are more typical for this pin, just as @DirkBruere suggested.
So, from the datasheet it is clear that 1) you don't need resistor at all, but 2) if you add it then 1 MOhm resistor will work, although smaller value is more appropriate.
Comment: @MSalters I think that resistor in suggested layouts could be a simple "everybody does it" mistake. Another possibility is a holdover from similar part with undervoltage control function. A lot of DC-DC regulators use EN pin to provide user-selectable startup threshold. Somebody who drew a dozen schematics for those could simply copy-paste without much thinking.
Comment: Thank you @Maple. your explanation regarding how much voltage will appear across the resistor answers my question. I am using 1MOhm because originally I had the EN pin connected to Vin as shown in the first diagram in your answer. When looking at the recommended layout, they all have a 1MOhm resistor (even though there is no mention of this throughout the datasheet- hence my confusion). Because the datasheet has a 1MOhm resistor in the recommended layout, should I keep this high value resistor, or should it be reduced in size or even removed?
Comment: @MRB: From a inventory and production perspective, choose a value that's already used somewhere else in the design. So if you've got a 100kOhm elsewhere, use that here as well - the production line will already have a tape with 100kOhm resistors.
Comment: @MRB: I suspect the suggested resistor is to prevent accidents. A short overvoltage transient won't kill the part; that takes both voltage and current (=energy). But if you connect EN directly to Vin, with its associated Cin, then there's no need for additional protection.
Answer: No, everything in the datasheet says there is no need for a resistor, EN can be directly connected to Vin.
Datasheet says EN pin has no internal pull up or pull down resistor, it must not be left floating, and it can handle whatever voltage there is on Vin.
However, it is not wrong to connect it via a resistor, for some purposes it might be even beneficial to do so.
Answer: Put in a pullup resistor. 10k is usually nice. It's easier to short one out or replace with zero ohm resistor than try to add one later. Also read the data sheet!
Comment: @MRB datasheet does say a lot of things.
Comment: @MRB No, that's not correct. The pin has a high input imepdance and draws essentially no current; why would the entire supply voltage drop across the pullup resistor?
Comment: I read the datasheet and it says nothing. If I put a pull up resistor (10k, 100k, etc) the resistor (in series with the enable pin) will 'take up' all of the supply meaning at the other end of the resistor (i.e. at the enable pin) there will be 0V? Is this correct?


How can I find the images in my Lightroom catalog that don't yet have smart previews?

Question: I have hundreds of images that weren't able to build a smart preview since the drive that was containing my Lightroom smart previews ran out of space. I would like to know how to find those images that don't have a smart preview. How can I do so? Thanks!
Comment: If you follow the [steps in the manual](https://helpx.adobe.com/lightroom-classic/help/lightroom-smart-previews.html) are you able to build smart previews? Can you perhaps edit your answer to indicate what you've looked into so far, such that people don't suggest things you've tried/read already?
Comment: But I don't know which images had a smart preview built and which didn't, so I can't just manually select the images and then make Lightroom build a smart preview. Thanks!
Answer: You can find photos without a smart preview by using a smart collection.
Go to Library → New Smart Collection... and add a condition Has Smart Preview is false:

This gets you the photos that do not have a smart preview.
Then you can follow the steps from the manual to create smart previews on the fly.
Comment: Hmm, that's not a good use of smart previews. If you have really important images you need a back-up. There is no way around that. Smart previews might become corrupted, are low quality (as you already noticed) and are only readable by Lightroom. If you lose your images, you do not want to depend on a commercial software package like LR to be able to restore images. Storage is relatively cheap (depending on where in the world you are). I would like to urge you to consider a real backup.
Comment: Glad to be of help. Do check if you actually need the smart preview, perhaps a regular preview is sufficient. You can Google around to see what pros and cons are.
Comment: Also, your technique allowed me to find out that I had over 5,500 images that didn't build a smart preview. I previously thought that they also had smart previews. By the way, I actually have a catalog of about 5,700 images. Thanks!
Comment: Oh, thank you so much! I already know how to create a smart preview for a particular image that I know doesn't have smart previews, but I didn't know about smart collections. Thanks!


future in the past or would have+ past participle?

Question: "He would have never dreamed that he would get the grant or that he would have got the grant ? " which is correct? according to most grammars only the first is correct(future i the past) but I gather from sources and spoken language that the second alternative is also correct or is it just tolerated as many other incorrect utterances/expressions are?
Answer: Both would+infinitive and would have+past participle can be used to express the future in the past.
If you said "I believe that I will get the grant", that would backshift to "I believed that I would get the grant".
If you said "I believe that I will have got the grant", that would backshift to "I believed that I would have got the grant".
You could say either "I can't imagine that I will get the grant" or "I can't imagine that I will have got the grant", depending on the intended shade of meaning, and when talking about the past, the latter backshifts to "I couldn't imagine that I would have got the grant".
From Thomson & Martinet, A Practical English Grammar (1985), ch. 21:

The perfect conditional... is used... (c) as a past equivalent of the future perfect:
I hope he will have finished before we get back.
I hoped he would have finished before we got back.

(Note: BrE uses "I have got" and "I would have got", etc; AmE uses "I have gotten" and "I would have gotten", etc; both varieties use "I have got" as a colloquial equivalent to "I have" as a present tense main verb expressing possession.)
Comment: your answer is satisfactory from a grammatical point of view, but I have noticed the perfect conditional used by native speakers in sentences that don't semantically backshift to future perfect. I mention native speakers because for an Italian to use this tense instead of would + verb would be an understandable mistake as he/she would be translating from his/her native tongue.


How to reduce Fe(III) impurity in Iron(II) sulfate?

Question: I have bought 50 kg $\ce{FeSO4}$, but it was stored on air, and it has turned to brown. Is there a cheap method to recover some $\ce{FeSO4}$?
Comment: Quite possibly, most of your $\ce{FeSO4}$ is still good. Whether or not some admixture of $\ce{Fe}^{3+}$ will do any harm, depends on your application.
Comment: @inɒzɘmɒЯ.A.M I was confused by the title at first but the question itself is clear enough, some of the iron(II) was oxidised by air.
Comment: @user21150 Please add the information (that you want to use it for gardening) to your *question*, because people don't want to read the comments to be able to answer. There is an edit link just below the tags.
Comment: You speak of Iron(III) sulfate in your title, yet your question's body only contains Iron(II) sulfate. Care to clarify?
Comment: FeSO4×7 H2O is green/blue, but when I opened the bag I saw a brown/yellow stuff, with some green parts. So I think it has oxidated. It was not good idea to store outside. I've read that when FeSO4 oxidates Fe2(SO4)3 + Fe2O3 is the product. I need ironsulphate for gardening (lowering the pH in soil). Do you think it is still usable?
Thanks for reply.
Comment: Please let us know how much you want to use at once, and how big an area that you want to spread the compound on. We need to separate beaker experiments from "gardening."
Answer: I recommend you dissolve your iron sulfate in hot water, dissolving as much sulfate as possible in as little hot water as possible. While keeping it hot, dip some coiled iron wire in it as well as some steel wool, and stir gently. The metallic iron should reduce your iron III back to iron II.
Once the solution is clear green, remove the iron wool, but keep the iron wire in it, and let it cool down as slowly as possible, while protecting it from air the best you can. Finish the cooling by putting it in a fridge
You should be left with beautiful large, green crystals of highly pure iron(II) sulfate heptahydrate, and a clear solution of relatively dilute iron(II) sulfate.
Since you have 50 kg of it, you will likely have to proceed in several batches, so I recommend you keep that solution for the next batch to minimize product losses.
Once you are done recrystallizing your iron sulfate, you can heat up that solution to a boil, until some crystals start forming on its surface. Then, immediately stop the heating and cool down that solution again. You'll have some lower grade iron sulfate, but that should still be perfectly usable for gardening.
And if you want to keep some of the prettiest crystals you made in the process, I recommend you keep them in a sealed container with a small piece of moist cloth. Otherwise, they may tend to slowly dehydrate and turn into powder.
Comment: For gardening application, do you think it need any processing at all? From the description it seems most of the material is iron(II), and I don't think gardening would need high purity material. Also, in this scale it sounds like an awful slow reduction reaction.
Comment: Hi! Thanks for the advice. I'll try it spring. I've spreaded 25 kg yet on 1000 sqm. I made solution of pH 4.5. It was 1 month ago, but it seems that the soil pH is still the same (~7.8). I'll try the recrystallizing, and write the results.
Answer: I have purified $\pu{1 kg}$ of old iron(ii) sulfate, which was yellow to brown color, using this method:
At room temperature add $\pu{10 ml}$ of diluted $\ce{H2SO4}$ (about $10 \%$) to $\pu{40 ml}$ of distilled water, scale up to prepare enough quantity of such mixture (you can use $37 \%$ battery acid in first step, in second step I have used chemically pure $96 \%$ sulfuric acid, of course recalculate the amounts to obtain the same concentration).
Dissolve as much as possible impure iron(ii) sulfate in such acidified water (prepare saturated mixture), stir very well, let impurities settle down and after decantation filter using very fine filter paper (slow filtration).
Then make first crystallization. If it does not start, you have probably not saturated, but diluted mixture, you can promote crystallization with evaporating (do not boil!), ventilation or cooling (do not freeze!). Finally you should obtain small light-green crystals.
Then wash crystals with ethanol ($96 \%$).
If you are not doing second crystallization immediately, then store intermediate product in vacuum bag to avoid reaction with air (without any desiccant!).
For second crystallization (i.e. re-crystallization), prepare the same acidified water, but with high purity $\ce{H2SO4}$ (p. a. or chemically pure), heat to max. $\pu{55-60 °C}$, and dissolve intermediate product, prepare saturated mixture.
Filter until hot using fine filter paper to crystallization dish and put dish to thermally isolated box, leave it overnight. You should obtain very nice and pure crystals. If not, the solution was not saturated, you can help using cooling (do not freeze), or ventilation, or if you are not satisfied with the result, you can do another recrystallizations.
Gently dry the crystals and put them in vacuum bag, without desiccant.


Is hardening off necessary whenever you uppot a plant?

Question: Is hardening off necessary everytime you uppot the plant? Otherwise, how do you let the plant recover from transplant shock? Or won't the high temperature kill the plant whose roots are not established? Here temperatures reach 42 degrees celsius.
Answer: You don't need to worry about hardening off when it comes to repotting. What you need to worry about is basically transplant shock (which is generally caused by sun exposure to a plant with damaged roots). It causes plants to wilt and sometimes die. Here are some things you can do to reduce the odds of sun damage after repotting, for most plants:

Don't repot between the hours of 9 AM and 6 PM. The sun can be too strong during those hours. It isn't always, but if you want to be sure, this is a good idea. Also, check the UV index; ideally, it should be 0 (or as close to it as you can get). You can ask Alexa 'What's the UV index?' and she should tell you a number most of the time (every once in a while she'll just look up what UV index means, though; if that happens, just ask again). How strong the sun looks and feels to a human in the moment isn't a good measure of how it will affect a plant; so, that's why it can be good to transplant during specific hours, and when the UV index is 0. The temperature doesn't really matter a terrible lot (a cold sunny day can sometimes be worse than a hot sunny day, and vice versa). It's the specific kinds of light that the sun produces (and the difference between kinds of light isn't always obvious.)
Give the plant some potassium sulfate or monopotassium phosphate. (This helps plants absorb more water, and it strengthens the roots. While it's not required, it can prevent shock, and help shocked plants to recover.)
Water the plant generously (don't waterlog it, though).
Don't give the plant nitrogen. Nitrogen makes transplant shock worse.
Answer: "Hardening off" in most cases refers to taking a plant with soft, weak tissues generated by growing in a protected environment and gradually exposing those tissues to outside effects such as lower temperature and wind. A sudden exposure to these effects can break or disturb a plant even if it is not moved to a larger pot.
The main reason to move a plant into a larger pot is because the existing pot is too small to accommodate the expanding root ball. If there is still room for roots to expand then there is no need to move to a larger pot, and indeed there are good reasons not to pot "up". Far better to wait until the existing pot of soil is fully explored by the roots; that way when you do move to a larger pot the existing root ball comes out in one piece and is easily placed in the new pot. Otherwise a very loose root ball can easily fall apart with consequent physical damage to the fine roots, a very different kind of damage compared to wind or low temperatures.
When moving a plant to a higher temperature, might be better to gradually expose it in its existing pot for a week or two and let the pot fill with roots. If it is already fully expanded into the pot then it can be transplanted immediately without concern for shock since it should come out in one piece with minimal damage.


Are there sha 512 rainbow tables available?

Question: Are there sha 512 rainbow tables available for download or what kind of dimensions and processing power would be required to generate them?
Comment: Do you mean SHA-512 or SHA-512 crypt? Rainbow tables only work against unsalted hashes, and even then it's dubious if they're actually better than directly using a GPU based cracker.
Answer: Possibly, but given their size - much more likely to download a generation tool and a word pattern list.
Rainbow tables are a carefully comprised collection of dictionary words and probable combinations in order to save on space.
A rainbow table sufficient for alphanumerical passwords of up to 9 characters is 864 GB in size. A rainbow table for this level entropy will be the size for any hash (MD5, SHA-1, SHA-512, etc) as rainbow tables are actually hashes hashed down to the entropy of the passwords (say, 254). The uniformity distribution requirement of the cryptographic hash makes this possible, but hashes with much larger bit space than the password entropy will have some collisions when hashed down to lower entropy level. Hence the "success rate" column of the rainbow table.
As 900 GB is tolerable for a determined hacker and as people that use alphanumeric passwords less than 10 characters exist, websites will use random salting to foil a rainbow table plus often use a slow key derivation function like PBKDF2 or scrypt.
None of these truly stop matching of a hash to password in a (much slower "sparse" meta-mega) rainbow table if the attacker got their hands on the server's user table. Which is why not using the same password across multiple sites is important.
Comment: @CodesInChaos Yes, I've not deeply looked into rainbow table construction, but I'd assume that the success rate column (e.g. 99.9%) refers to hashes that are themselves hashed to smaller space 2^54, with only a few collisions. I'll update answer.
Comment: I don't think output size of the hash is relevant to rainbow tables. There is no reason for a rainbow table to store full hashes.
Comment: @CodesInChaos I thought rainbow table stored the hash of the last reduction function for each line of the table. What does it store? The last reduction function result?
Comment: @FredericoSchardong You could simply truncate the hash. Using the same reduction as everywhere else should work as well. I'm no expert on rainbow tables and I don't know what actual implementations use, but storing a full 512 bit hash strikes me as obviously silly.


Intranet GIS app with JS web app builder?

Question: Is there a work-around for building an intranet GIS app with ESRI JS web app builder (without sharing data to the public)?  Does it mean that I have to create a web map in ArcGIS com or is there an alternative?
Answer: Akis,
I think the answer to "Q3" on the blog post Clarifying 3 questions about Web AppBuilder for ArcGIS probably best answers your question.
Just an added note that you can certainly author a Web Map that does not share data to the public, and then use Web AppBuilder to build an app based on that web map. Either:

create a web map that contains a Hosted Web Layer that is not shared to the public, or
create a web map where you "add layers from the web" referencing internally hosted ArcGIS Server Services. A reference to the data (the url) is stored in the webmap, but your data is still protected behind your network firewall.


Question on output of an FPGA

Question: I have been trying to solve this basic FPGA problem with multiplexers, but I cannot garner the meaning of the notation 0/1. Can someone throw some light in this regard? What do notations like 0/1 mean? Is it that the input can be either 0 or 1?
Answer: You are correct in your understanding. The [0/1] represents a 1-bit ROM (or Lookup Table). Each of these 1-bit ROMs are programmed by a bit-stream when the device is turned on in order to configure the behaviour of the logic.
In this case all four 1-bit ROMs can be programmed to allow all possible outputs based on the two inputs to be configured.
For example if you set the value in the four ROMs to [0 0 0 1], you would form an AND gate. Set to [0 1 1 1] you form an OR gate. You can make any of the sixteen possible outputs.
In terms of solving the question, I presume you are given more information as to the value in the ROMs.
Comment: So, just as an addendum, for inputs like 0/1, we cannot have any definite output in this case, right?
Answer: Yes, the input can be either 0 or 1. This is a lookup table, the fundamental unit of FPGAs; when programming the FPGA you program in what each of these inputs is.
I don't think this question is solvable without more information. You would need to know what at least one of the programmed values is.
Comment: Or at least you need to name the ROMs, so you can answer something like "When A=1 and B=1, the output is whatever is in ROM number 3".

Question on output of an FPGA


Why do my tires keep losing air, even after having the tubes replaced?

Question: I had a problem a few weeks ago where my tires were flat and needed air every time I took my bike out of the garage. I brought it to the local bike shop, and they replaced my tubes.
This made a difference for a little while, but unfortunately, I seem to be back where I started. I have to fill up the tires before each ride, and then the wheels are flat after just a few minutes.
The bike is about seven years old, but I like it and this is the only problem it's ever had. Do I need a new bike, or is there something other than a bad tube that could cause this to happen?
Comment: See the following questions.  http://bicycles.stackexchange.com/questions/8073 http://bicycles.stackexchange.com/questions/6753
Comment: Take it back to the shop -- likely either the tube was defective or they damaged it while mounting it.
Comment: I have this problem and the inner tube ( expensive one) and tyre are brand new. Deflated the first night and not even ridden it yet?
Comment: It would help adding the following information to the question: all the text on the sidewall of the tire(look closely it's hard to read even when clean); pumping pressure(if unknown You can probably use a gas station pump - they have pressure gauges and tend to be free of charge).
Answer: It's not unusual for narrower tires to need pumping up every day or two, but if they really are losing air after "a few minutes" then the tubes have been holed somehow.
Did anyone check the tires for small pieces of wire, etc, sticking in them?  A tiny piece of wire can puncture a new tube within minutes.  Did anyone check the rims to make sure that the rim strips were intact, and no spoke ends were sticking out?  A missing or miss-positioned rim strip can cause a tube to puncture in short order.
At seven years old your bike is a mere adolescent, and there's no need to replace it on account of this problem.
Comment: Take the tube out, mark the tire and tube so you know exactly how they were aligned to the rim and each other. Pump up the tube and stick in some water/soap - look for bubbles. Once the puncture is found, go back to the tire/rim, and find whatever it is that made the hole.  If you can't do this yourself, go to a different bike shop than the last one and ask them to do it.
Comment: I've never needed to use water/soap to find a leak.  Just inflate the tube to near twice normal diameter and listen/feel for leaks.  Your face is particularly sensitive to the feel of the escaping air.
Comment: Last time I had to dig the wire out with a knife.
Comment: I agree with these guys, there is definitely something on your wheels or tyre that is wearing a small hole (or holes) into the tube. Use @mattnz method to find where the hole is (probably don't need soap, just a sink or bucket of water). Instead of marking the tube/tyres it is common to make sure the brand/logo on the tyre is in the same position as the valve for pumping the tyre up. If you religiously follow that (most bike shops do) you will not need to mark the tube/tyre. Last time this happened to me there was a *tiny* piece of wire sticking slightly out the inside of the tyre.
Comment: I agree with the suggested refinements, I was going for the idiot-proof version of finding the cause of punctures :)
Comment: +1 re: tiny piece of wire.  Minuscule filaments can become embedded in the tire and only present themselves rolling under high pressure (that is, you won't find them running your thumb around the inside of the tire.)  +1 to mattnz for the technique to find the things!
Comment: If the wire is ferrous you might be able to get it out with a magnet in a plastic bag (the plastic bag is so you can get it off the magnet and dispose of the rascal).
Answer: I had this problem, and I found that there was a small piece of glass in the tire that was puncturing every inner tube I put on the bike as soon as I inflated it.
Don't just run your finger inside the tire you will cut your hand.
Comment: You can mark your own answer as "correct" or you can mark the top answer (which has a number of good insights) as correct. It's good karma (and adds to your own point count).
Comment: I don't appear to have a mark this answer as correct button. Maybe the question is too old?
Answer: You don't mention the type of bicycle you're referring to, but if you look at your wheels with the tube out and the tires off, you can probably see what the root cause is.
Bicycle wheels should have rim tape or a rim strip that protects the tube from the spoke holes in the rim. Of the two approaches, the rim strip is the more modern. The rim strip can be rubber, or plastic, or a slightly stretchable woven material (polyester fabric, for example).
Usually if you have an undamaged rim strip of the correct size for your wheel, it is highly unlikely that your tube is being punctured by contact with the spoke holes/spoke nipples. It might be cut by the hole where the valve stem goes through the rim, but if so it should be obvious.
However if you have rim tape, even if it is the correct width, it's possible the rim tape is not adhering to the rim in one or more locations, and could be moving around under the tube, thus exposing the spoke holes, and causing your tubes to pop.
The leak you describe-- taking a few minutes to become flat-- suggests a small hole, and this is not inconsistent with a tube cut by a spoke hole, but usually such a cut is big enough to let the air out almost immediately.
To find out, inspect your leaky tube. Remove it from the wheel, and pump a bit of air into it. Where is the hole? If it is on the valve side of the tube-- the portion which comes into contact with rim tape/rim strip/spoke holes-- then this may be your problem. Hold the tube under water, if necessary, to see where bubbles emerge.
If the hole is on the outside of the tube, where the tube is in contact with your tire, you need to check the tire carefully. One might expect the bike shop did this, but you never know. Run your fingers over the inside of the tire. As the other responder suggested, you can get a small hole from a piece of wire (a "michelin thorn") that has punctured your tire casing, or a goat-head thorn, or a piece of glass. You need to remove that from the tire casing, or it will puncture every new tube you put in.
Comment: It's a hybrid bicycle, made by Raleigh.
Comment: Good quality rim tape should adhere for many years, but manufacturers don't always use good quality tape. Take a look at this: http://sheldonbrown.com/flats.html
Answer: As well as the good advice given by others, sometimes the valve leaks. This should show up on the water test.
I have this problem on one of my wheels but not on the other. At the moment, I can get away with pumping up once or twice a week.
Comment: Probably not the cause as he's replaced the tubes and presumably the valves are built-in.
Answer: Try using a different pump. I had the same problem and couldn't find a leak, replaced the tube and still had the same problem. Eventually I tried a different pump and no problems. The pump I had must have been damaging the valve.
Comment: Gidday and welcome to SE Bicycles.  Good contribution, I look forward to your future answers and questions.
Comment: Never encountered this, how could that even happen? :O
Answer: One thing I've read is that if you ever ride on under-inflated or flat tires, doing that can give you a pinch flat.
Answer: Make sure your valve core is tight. You can buy a valve tool at your local auto parts store. If the valve core is tight, you have a hole if it goes flat in a few minutes. Replace the tube and check your rim strip to make sure it is covering all the spoke ends. I prefer thorn resistant tubes. They last about 10 times longer between flats and hold air longer. They are heavier and more expensive but it beats changing flats all the time.
Answer: The most likely cause is a poor quality valve, one variant of built-in obsolescence. The idea is you buy good stuff and can take it easy, or you buy cheaply and suffer.
Unable to accept that modern marketing could be so manipulative, I rode on cheaper (department store bought) tyres for many years. No fun.
Since switching to high-quality touring tires a year or so ago, I find they remain rock-hard for months at a time AND I have yet to have a puncture (that includes 4 week's cycling in the thorny Extremadura in Spain).
My wife uses a similar tyre (different brand), and claims to have been cycling on the same tyres for two years without a single puncture.
Comment: I can't ever recall encountering a bad valve, either on a bike or a car.  Occasionally you'll run into one with a *very* slow leak, but usually just operating it a few times will seat it properly.  You can easily destroy a Presta valve, though, by wrenching it down too tight.  (But definitely getting good quality belted tires will reduce punctures to virtually nil in most circumstances.)
Comment: Welcome to Bicycles! You may want to clarify when you are talking about the Tyre, and when you are talking about the Inner Tube. Other than a puncture, the tyre would seem to have nothing to do with a slow loss of pressure.
Answer: I had the same problem, and with the use of reading glasses I finally
found a very small hole in my tire.  Use some super glue, JB Weld or similar to fill the hole in the tire.
Comment: Welcome to Bicycles SE. A tiny hole in the tire isn't likely cause this problem. As others have mentioned, it's more likely that there is a small object embedded in the tire. A piece of wire from an automobile tire is a frequent culprit.
Comment: Tyre or tube?  A hole in the tyre / tire is generally okay, unless you're on some kind of tubeless system.


Any recommentadions of DAWs that can interact with external piano?

Question: I must say that I don't even know how to explain my problem, but here I go. The thing is: I have an piano digital (yahama 36keys), but it's been a while since I got bored with reading sheets and just playing along. So, with a MIDI cable, I decided to donwload a simple DAW where I could play and actually see the notes/modify them if possible. Just like synthesia does, but recording. I'm afraid that if I just look for some software which does the recording, I won't be able to use the "styles" that came with the piano. 8 beat, jazz, flute, etc. Plus, it would be a pain to record with X, add some drums with Y, then finally mix them together with Z. There has to be something that does all of that...
Comment: I prefer trackers, and my favourite one is [Renoise](https://www.renoise.com/). But I have a background in chiptune, so it might not work for everyone. It's a bit more of a technical program, but they have a great community and their FAQ section is extremely extensive. Also, it's pretty damn cheap for an amazing DAW/tracker.
Answer: Just about any standard DAW you get will do what you're asking. Pretty much any software package you get will come bundled with a decent set of virtual instruments. I personally use Cubase which came with a decent virtual sound set, but Pro Tools, Ableton Live, and FL Studio are other common DAWs you might look into. You can get lite or basic versions of just about any of them too which would probably still include some of your virtual instrument sounds. Most of them should be pretty much plug-and-play with your keyboard too.
Comment: Since Cubase is the one I know, I can tell you that it has a fantastic MIDI editor tool where you can edit each individual MIDI note that you play (velocity, pitch, length, etc.). And I only have the Elements version of Cubase (the lite, cheaper version, not Pro) I would assume the others I mentioned have similar capabilities but I'm not as familiar with them.


Concatenate text and number fields

Question:
Hi all I am using a flow to update a record which is a text field(Name__c).In the assignment section in the picture I am assigning a number to a variable varNum.Now I have to concatenate this number with a text "Modification" and use this combined variable in the update record and update field(Name__c) with this value Modification-01 for eg.I tried using a formula but not working.
"Modification" & " " &{!VarNum}
Answer: You have the following situation

a number variable (VarNum)
Text you'd like to use (Modification)
You want to combine the two as one text value

The obvious conflict is that you can't combine a number and text directly. Since your goal is text, you need to convert the number to text in your formula. You'll want to most likely go through Use Text Formulas trailhead which covers this exact scenario:

TEXT() converts a Percent, Number, Date, Date/Time, picklist, or Currency field into Text. TEXT() returns output without any formatting, commas, or currency signs

As such, just adding that should allow you to do what you want
"Modification-" & TEXT({!VarNum})

Comment: Thanks @Kris Gonclaves. Consider i have to add a lookup field as well.For eg Here my record is Grant Contract Modification and I have a related object Grant Contract.Master contract given in grant Contract Modification to Grant Contract.I can only get the name of the related field.I can only get the id if I fetch the lookup.

Concatenate text and number fields


Integral variable substitution using Hausdorff measure

Question: Suppose we have positive density $q$ with "good" qualities (continuity, etc..). I need to calculate this integral:
$$\int_B q(\textbf{z}) d \textbf{z},\ \textbf{z} \in \mathbb{R}^d,$$
where $B \subset \mathbb{R}^d$ is a Borel set that is bounded away from the origin.
In order to do that it is necessary (in my case) to make a d-dimensional "polar coordinate" substitution, where $r=||\textbf{z}||$ ($||\cdot||$ is $L_2$ norm) and $\textbf{w}=\textbf{z}/r$, respectively are "radius" and "direction".
$$\int_B q(r\textbf{w}) r^{d-1} drd\lambda(\textbf{w}),$$
where $\lambda(\textbf{w})$ is Hausdorff measure (I assume the "surface area" on d-dimensional hypersphere).
The question is how do I prove  that Jacobian is $r^{d-1}$? I found that this is the right Jacobian for this transform in this article p. 1818 and also intuitively the idea looks fine, but I could not find a mathematical proof anywhere. I know how to find Jacobian in the simple cases like d=2, or d=3, but I don't really know how to deal with this Hausdorff measure.
Comment: It's not really trivial. You may proceed by induction on the dimension. But the cleanest proof is by the co-area formula.
Comment: You can think as it being the Riemann integral since you q is continuous. If q is positive and  symmetric radial you may use the distribution function $\omega(\alpha)=|{|q|>\alpha}|$ and integrate it from zero to infinity to obtain the result desired!
Answer: Easiest way is to use really simple idea - two dimensional polar coordinates. Vector $\mathbf{z}$ can be mapped to vector $(r \cos \phi,  r \sin \phi, rw_3, rw_4, \dots, rw_d)$, where $\phi$ and $r$ are such that $w_1=r \cos \phi$ and $w_2=r \sin \phi$. Then the Jacobian is
$$
\left|
\begin{array}{ccccc}
    \frac{\partial r \cos \phi}{\partial r} &
    \frac{\partial r \cos \phi}{\partial \phi} &
    \frac{\partial r \cos \phi}{\partial w_3} &
    \cdots  &
    \frac{\partial r \cos \phi}{\partial w_d}  \\
    \frac{\partial r \sin \phi}{\partial r} &
    \frac{\partial r \sin \phi}{\partial \phi} &
    \frac{\partial r \sin \phi}{\partial w_3} &
    \cdots  &
    \frac{\partial r \sin \phi}{\partial w_d}  \\
    \frac{\partial r w_3}{\partial r} &
    \frac{\partial r w_3}{\partial \phi} &
    \frac{\partial r w_3}{\partial w_3} &
    \cdots  &
    \frac{\partial r w_3}{\partial w_d}  \\
    \vdots   & \vdots   &\vdots    & \ddots  & \vdots \\
    \frac{\partial r w_d}{\partial r} &
    \frac{\partial r w_d}{\partial \phi} &
    \frac{\partial r w_d}{\partial w_3} &
    \cdots  &
    \frac{\partial r w_d}{\partial w_d}
\end{array} \right| . $$
Then by taking derivatives and evaluating determinant we get that Jacobian equals $r^{d-1}$
Answer: What we have before us is an instance of "Fubini" in disguise.
I assume your $B$ is a ball of radius $R$ centered at ${\bf 0}\in{\mathbb R}^d$. Since the integrand $q(\cdot)$ is well behaved we can use an approximation by Riemann sums in order to arrive at the correct formula.
Partition the interval $[0,R]$ into $M$ subintervals $I_i:=[r_{i-1},r_i]$. Likewise, partition $S^{d-1}$ into $N$ essentially disjoint patches $\Omega_k$, and for each $k\in[N]$ choose a sampling point $\omega_k\in\Omega_k$.
In this way you obtain a partition of $B$ into $MN$ essentially disjoint pieces $$B_{ik}:=\{{\bf x}=r \omega\,|\, r\in I_i, \ \omega\in\Omega_k\}\ .$$
The $d$-dimensional volume of $B_{ik}$ is given by (this is elementary geometry)
$$\eqalign{\mu(B_{ik})&={1\over d}(r_i)^{d-1}\lambda(\Omega_k)\cdot r_i -{1\over d}(r_{i-1})^{d-1}\lambda(\Omega_k)\cdot r_{i-1}\cr &={1\over d}(r_i^d-r_{i-1}^d)\lambda(\Omega_k)=\rho_i^{d-1}(r_i-r_{i-1})\lambda(\Omega_k)\ ,\cr}$$
where a suitable value $\rho_i\in I_i$ is guaranteed by the MVT of differential calculus. In particular $\rho_i\,\omega_k\in B_{ik}$ for all $i$ and $k$..
Now we approximate our integral as a Riemann sum:
$$\eqalign{\int_B q({\bf x})\,{\rm d}({\bf x})&\doteq \sum_{i,\, k} q(\rho_i \omega_k)\ \mu(B_{ik})=\sum_{i,\, k} q(\rho_i \omega_k)\ \rho_i^{d-1}(r_i-r_{i-1})\lambda(\Omega_k)\cr
&=\sum_k\left(\sum_i q(\rho_i \omega_k)\ \rho_i^{d-1}(r_i-r_{i-1})\right)\lambda(\Omega_k)\cr
&\doteq\sum_k\left(\int_0^R q(r \omega_k) \,  r^{d-1} dr\right)\lambda(\Omega_k)\cr
&\doteq\int_{S^{d-1}} \int_0^R q(r\,\omega)\, r^{d-1}\ dr \ {\rm d}\lambda(\omega)\ .\cr}$$
Since the used approximations can be made as precise as desired, the integrals on the LHS and the RHS of this chain have to be of equal value.
Comment: Although, I forgot to mention that B is a Borel set that is bounded away from the origin and not necessarily a ball set, I see the point in your proof.


YouTube comments notification

Question: I used to get notifications from various comments that were replying to me or were in the same comment chain. But suddenly the notification (little bell icon) started displaying only YouTube videos that were uploaded by my sub channels (the ones where I chose to get notified). To avoid that I disabled the notification from upload. But the notifications don't change at all. If I click on a notification for a video and I see the video the notification doesn't go away. Those specific notifications have gotten stuck in there. The settings don't have anything to address this and I just cant get notifications from comments anymore.
Is this a bug? This didn't happen gradually. One day I went to my notifications and they are just stuck that way ever since ,the same specific notifications. Even though I had enabled the video notifications much earlier in various channels. But they just got there all together and they cant be deleted.
Answer: The old bell was part of Google+. Google+ is getting removed from YouTube, so the bell, too, had to go. The new bell does feature videos (ie it mirrors push notifications you might get on your phone), and doesn't support in-line replies yet.
You can set upload notification on a per-channel basis on youtube.com/subscription_manager (the bells next to the subscribe button), and you can set whether you want comments on your videos and comment replies in your bell on youtube.com/account_notifications.
If you have feature requests or discovered a bug, do send feedback to let the developers know. You can send feedback at the bottom of any YouTube page (old design) or at the bottom of the sidebar (new design).

YouTube comments notification


How to improve joint cartilage thickness

Question: Does anyone know of exercise or modality(ice/heat/tens) protocols that are supposed to increase joint cartilage bed thickness? This is excluding stem cell injections. I imagine that such a protocol would be more effective with children and younger athletes who still have stem cells present in their joints to create the repair. However I don't know if any research that measures stem cell density inside of joints for different age populations or for different exercise programs.
Answer: Articular cartilage, which covers the ends of bones in all synovial joints is avascular.  Without a blood supply it is unable to heal or regenerate.  Over time the loss of this cartilage is what causes the condition known as osteoarthritis.
The modalities you've listed are indicated for swelling / healing and pain management.  So they'll only help with secondary symptoms that are seen with cartilage loss.
Stem Cells seem to offer the most promise but nothing has been approved yet.
Kobe Bryant had a non FDA approved treatment called Regenokine done in Russia, you can read about the procedure here.
Answer: Physician and Professor of Medicine David Rabago (Penn State University) has published multiple articles suggesting the modality known as prolotherapy stimulates cartilage re-growth, including a review article, a clinical study with pre/post-arthroscopic images of cartilage growth, and a basic science study on molecular mechanisms of which the poster is a co-author.
Comment: I'd give more specific suggestion but I feel like the question approaches medical advice, and I'm a bit uncomfortable with an answer that suggests a treatment that seems outside the mainstream. Perhaps an answer that focuses more on the biology as well as the lack of medical clarity would be best.
Comment: To avoid being accused of spam, you should disclose when you have a relationship with links you post, like when you're an author of the papers or have worked with the author. Also, importantly, Stack Exchange answers must *stand for themselves*. Though it is fine to link to and *required* to cite outside resources here at MedicalSciences.SE, readers shouldn't have to leave the site for a complete answer.
Comment: @BryanKrause I appreciate you helping me to improve my first post to StackExchange. What additional information do you think would be helpful for a more complete answer? How physicians administer prolotherapy in practice? Background on the history of the procedure? More details on cartilage biology? Potential differences in therapeutic effectiveness across age groups?


Arduino diy wireless

Question: Is it possible to do simple wireless on an Arduino, digital, or analog (SDR)? I would like to hook one pin to an antenna (or piece of wire) and generate signals with simple modulations (analog or digital).
Comment: You really need to expand on your question: what is it you are trying to achieve, what data rates are you looking for, what range. Be more specific
Comment: "[AVR-based FM-transmitter](https://spritesmods.com/?art=avrfmtx)" describes a FM audio transmitter implemented by an overclocked ATTiny45. Within limits, this idea should be adaptable to an unmofdified Arduino but probably this would cause an FM transmission on a frequence not covered by common receivers.
Comment: "[Hook an antenna to your Propeller, and listen to the radio! (New shortwave prog)](http://forums.parallax.com/showthread.php/105674)" describes a shortwave receiver implemented unsing a Parallax P32x8A controller. Maybe some other readers here can estimate the power needed for this hack... perhaps a DUE could do this too?
Comment: You might also like this (quite unrelated) [raspberry PI PWM FM modulation](http://www.icrobotics.co.uk/wiki/index.php/Turning_the_Raspberry_Pi_Into_an_FM_Transmitter).
Answer: here there's a nice tutorial on how to obtain it.
Basically it sets the registers so that a pin outputs a PWM signal at 800 kHz and then modulates that signal in code by just switching the pin and off (pinMode set to INPUT or OUTPUT). If you plug a cable (20 cm and on) to pin 8, and tune your radio to 800Khz you'll hear some noise going on and off.
If you read down the forum you'll see people suggesting how to actually send tones, by putting a very small delay (delay(1)) between the on/off of the pin.
In this link they guys have ogn further and they even implemented a morse code library.
Now I am trying to figure out a way to do the same for a receiver.
Answer: Based off of what you have said, the simplest way to achieve what you want to do with your Arduino would be to use a WiFi shield, and setup the Arduino to function as a web server. I have included two links: the first link shows you Arduino's sponsored WiFi shield and explains the basics of how to use it. The second link addresses your question of using the Arduino+WiFi shield to generate WiFi signals, by setting it up as a web server. Both links contain sample codes from Arduino that you can copy and paste. Assuming that you are using the native Arduino software, you can also go to: File > Examples > WiFi > WiFiWebServer, and the same code from the Arduino websites that I listed will be there for you to use.
http://arduino.cc/en/Tutorial/WiFiWebServer
http://arduino.cc/en/Guide/ArduinoWiFiShield
Personally, I would always recommend that whenever you want to accomplish a certain task, such as WiFi signal generation, displaying characters on a LCD, or anything else, you search for a shield to use for that application. Shields always make life extremely easier. I hope this helps. :)

Arduino diy wireless


Streaming from VLC to Android via Multicast

Question: I've built a media player using VideoView to stream from VLC using multicast. I've provided the url and the application does stream the video. But when I check the Network Activity (In the resource monitor) it shows that VLC is connected to both the multicast address as well as the IP of the android device therefore the application is streaming in unicast.
The code I'm using:
VideoView videoView = (VideoView) findViewById(R.id.video);

Uri uri= Uri.parse("rtsp://192.168.137.159:8554/test.sdp");
videoView.setVideoURI(uri);
videoView.start();

I've also made sure that multicast packets are not filtered out using this code:
WifiManager wifi = (WifiManager)getSystemService( Context.WIFI_SERVICE );
if(wifi != null)
{
    WifiManager.MulticastLock lock = wifi.createMulticastLock("Log_Tag");
    lock.acquire();
}

Is there something else I'm missing in order tell the VideoView to stream from the multicast address and not directly from the server?
I've set up VLC to stream to a multicast address using these parameters: #rtp{mux=ts,dst=184.108.40.206,sdp=rtsp://:8554/test.sdp}
Answer: I think the whole point of RTSP consists of setting up unicast streams on demand. This works as expected. Use RTP multicast, nor RTSP, if you want that.


Smart Contract Interfacing - Best Practices

Question: what is a general rule of thumb for creating interfaces? Why would I want an interface i.e. IAugur.sol instead of the entire Augur.sol file? Can someone shed light on interface best practices and pros/cons.
Answer: There are two main reasons.

To minimize contract size
To ensure compliance

If you make the smallest possible contract and use Augor.sol, then your contract will be at least as big as Augor.sol.
contract Mine {
  Augor a;
}

You have defined a as an instance of Augor and that means all of the Augor bytecode is rolled up into yours. It's not evaluated for usefulness, so the fact it isn't used doesn't reduce the size of your contract.
If you, instead say:
IAugor a;

Your contract will include the code for the interface which should be much smaller. The interface is all that is required. It's a black box and its internal workings are not relevant. Only the function signatures and expected responses.
Interfaces are also useful for ensuring and demonstrating compliance. For example, one might say "My contract is an ERC20 token." Is it? Does it implement all the required functions?
You can say:
contract MyIncompleteToken is ERC20 {} // where ERC20 is the standard interface

It will compile but it will not deploy. It won't deploy because the interface laid out some functions and they have no implementation. This can help catch developer oversight. The inherited interface is a commitment to implement all the promised functions. It is not a catch-all for every compatibility concern, but it is helpful.
Hope it helps.
Comment: I think the 1 part of this answer is not correct, the size of your compiled contracts does not change whether you use and interface or the whole contract.
Comment: Interfaces are always smaller than the contracts they describe. Importing either will tell a client contract how to connect. Importing the smaller of the two options, the interface,  will make the client contract as small as possible. Importing the larger of the two options means that the internal logic of the functions, including the internal and private functions is all imported into the client contract. Most of it will be unreachable code, but it will be there.
Comment: Maybe we're talking of different things, I'm talking about the file bytecode, the part that actually makes it into the Tx. I've, tried both scenarios and, for example using "hardhat size-contracts" yields the same size. I think the compiler is "intelligent" enough to only include the minimum required to fulfill the necessary interactions, no more.
You can also try importing many contracts and not using them, the size doesn't change.
Answer: Because often when you're writing contracts which interact with other contracts, the internal workings of those contracts are not relevant, just the externally exposed functions. By providing an Interface, other developers can write code that interacts perfectly with yours, without needing to see/include your entire codebase.


Why did the width collapse in the percentage width child element in an absolutely positioned parent on Internet Explorer 7?

Question: I have an absolutely positioned div containing several children, one of which is a relatively positioned div. When I use a percentage-based width on the child div, it collapses to 0 width on IE7, but not on Firefox or Safari.
If I use pixel width, it works. If the parent is relatively positioned, the percentage width on the child works.

Is there something I'm missing here?
Is there an easy fix for this besides the pixel-based width on the child?
Is there an area of the CSS specification that covers this?
Answer: The parent div needs to have a defined width, either in pixels or as a percentage. In Internet Explorer 7, the parent div needs a defined width for child percentage divs to work correctly.
Answer: Here is a sample code. I think this is what you are looking for. The following code displays exactly the same in Firefox 3 (mac) and IE7.

#absdiv {
  position: absolute;
  left: 100px;
  top: 100px;
  width: 80%;
  height: 60%;
  background: #999;
}

#pctchild {
  width: 60%;
  height: 40%;
  background: #CCC;
}

#reldiv {
  position: relative;
  left: 20px;
  top: 20px;
  height: 25px;
  width: 40%;
  background: red;
}

Answer: IE prior to 8 has a temporal aspect to its box model that most notably creates a problem with percentage-based widths. In your case here an absolutely positioned div by default has no width. Its width will be worked out based on the pixel width of its content and will be calculated after the contents are rendered. So at the point, IE encounters and renders your relatively positioned div its parent has a width of 0 hence why it itself collapses to 0.
If you would like a more in-depth discussion of this along with lots of working examples, have a gander here.
Answer:
Why doesn't the percentage width child
in absolutely positioned parent work
in IE7?

Because it's Internet Explorer.

Is there something I'm missing here?

That is, to raise your co-workers' / clients' awareness that IE is not good.

Is there an easy fix besides the pixel-based width on the child?

Use em units as they are more useful when creating liquid layouts as you can use them for padding and margins as well as font sizes. So your white space grows and shrinks proportionally to your text if it is resized (which is really what you need). I don't think percentages give a finer control than ems; there's nothing to stop you specifying in hundredths of ems (0.01 em) and the browser will interpret as it sees fit.

Is there an area of the CSS specification that covers this?

None, as far as I remember em's and %'s were intended for font sizes alone back at CSS 1.0.
Answer: I think this has something to do with the way the hasLayout property is implemented in the older browser.
Have you tried your code in IE8 to see if works in there, too?
IE8 has a Debugger (F12) and can also run in IE7 mode.
Answer: The div needs to have a defined width:

Answer: The parent
 tag doesn't have any width specified. Use it for the child
 tags, it could be percentage or pixel, but whatever it would be,it should link to its appropriate positions:

        ...

        ...

    ...


Am I liable for 20 year old water bill for a house I bought?

Question: I bought a house in Florida in 2017 and when I went to get the water service turned on they told me there is a water bill from 1998 and I need to pay it. Is it my responsibility even if I didn't own the house and there had been 6 other owners before me?
Comment: How is it none of the previous 6 owners were required to pay this bill?  Did no one have water in this house for the past 19 years?
Answer: To get an answer tailored to your problem, you need to get a lawyer. The general answer is that the water bill goes with the property, not the person using the water. The unpaid bill can become a lien on the property, and the house can be taken and sold to satisfy the lien.
There are other factors / questions. Under Florida law (180.135), if the debt arises from a renter who incurred the debt directly with the utility, a lien cannot be placed against the property. Any lien must be perfected (filed with the courts), and the point of a title search is to find such liens – assuming that a title search was done. There is a limit to how long you can wait to collect on a debt (7 years).
Comment: If there's a lien, it seems to me that should be something that title insurance should cover.
Comment: Yes, except if the court is at fault (that is, the court clerk messed up and failed to register something).


strange potential plagiarism case(missed the acknowledgement page)

Question: Forgot to mention supervisor's name in the thesis(due to pressure) and submitted it and got an A for it. Can I be accused of plagiarism at a later date, if this professor wishes to push it forward? This professor was my thesis advisor or guide.There were some portions of the thesis which we both worked on it and some portion was mine. I missed the acknowledgment section
Comment: What kind of thesis, PhD, master, ...?
Comment: Master's thesis
Answer: First of all, the Ph.D candidate is always considered the only author of the thesis and the only one to respond legally in case of plagiarism. Despite all the input introduced by your supervisor along your research, he will never be entitled to accuse you of plagiarism due to the lack of acknowledgements. This is just an impolite thing to do, nothing more.
Comment: I think it depends on the field as to whether advisors' names go on theses. Not in math, usually.
Comment: @paulgarrett are you talking about publications during the PhD (in that case it's pretty common) or the actual thesis, which might contain the papers but even if that case I've never seen more than one author on the thesis itself. I also checked about 150 random theses on proquest right now and not a single one with more than a single author.
Comment: @paulgarrett really? Every thesis in every field I've ever seen lists the student as author and the advisor as advisor (sometimes in combination with an advisory board, the commitee, the reviewers or something similar)
Comment: @DSVA,  I understand your point. For a long time, that was my experience, too (I'm a mathematician). But in the last 10-20 years I've encountered many situations in engineering and computer science where, because the advisor supplied equipment and a room and a stipend, the students listed them as authors. There has been much discussion of such things on this and other similar sites.
Comment: @DSVA, ah, yes, the distinction between "thesis" per se, and "papers in it or derived from it" are two different things. Maybe it's not so clear what exactly the issue is for the OP...


How to prevent against booby-traps

Question: When attacking a base my troops have been decimated with booby traps (springs, bombs). Is there any way to counter this? I would space my troops out but this lessens the troops affected by spells such as rage and healing.
Comment: You could throw down a few barbarians down at the spots you expect traps to pop up. Other than that there is no reliable way to deal with them.
Comment: @Izzo this is very hard to do if you had already deployed giants to destroy the walls. Maybe it's a thought that you could deploy giants and barbarians at the same time and since barbarians move faster the traps would be "wasted" on them.
Answer: It's important to anticipate where you think traps are.  For instance, if you notice there are holes inside the base where there are no defenses, chances are a trap is there.  You can guess at what kind of trap by the size and shape of the hole - big bombs and teslas both require a 2x2 area to deploy in.
If you don't see any holes in the base at all, chances are the traps are around the outside.
Once you kind of have an idea as to where the traps are, it's time to bait them as best you can.  It's hard to bait traps deep inside a base, but relatively easy around the outside.
For traps around the outside of a base, dropping cheap troops or dropping a small first wave usually helps.  For instance, if they're outside the base, drop a couple of barbarians strategically around and see if you can trip them.  If barbarians won't immediately walk to where the traps are (ie, they are protecting other defenses and there are trash buildings in the way) drop one giant in the area you plan to attack and let him walk up to the base.
Once you've baited the traps, you can drop the bulk of your army, which will group them together enough for spells to be effective.  You're basically sacrificing the initial troop(s) to protect the rest of your troops from getting hit.  It's much better to have one giant hit a spring trap than 10, for instance.
If the traps are really deep inside the base, there may not be anything you can do - you can try to reserve a few troops for a last-minute push, and let the others attack and potentially get hit by the traps.  However, if you're evenly matched and the enemy has a smart base design, chances are the traps are going to be effective no matter what precautions you take.
As a side note, if you see that the person hasn't logged in in a long time (ie, all builders are idle, no league shield, lots of tombstones, etc), chances are their traps aren't even armed anymore.  Someone else has probably already jumped on that (literal) grenade for you.  Therefore, you can attack with a bit more confidence.
Also, note that you should learn from your raiding failures - the things you see that are particularly effective in other people's bases can help you design your own impenetrable trap maze.
Comment: Nicely put. And also triggering traps depends on what sort of troops you have. Say you have trained hogs, then you need to watch out for those giant bombs, rest are not that harmful.
Answer: In general, you need to focus on these key points to disarm Traps effectively:

Know where to anticipate Traps (this can depend what on what kind of troops you're using)
Know how to disarm the traps

I think the best way to address these points is to just start and you will get it pretty fast.
Find more details about this strategy here:
Prevent your attacks getting blasted by Traps Part 1
Prevent your attacks getting blasted by Traps Part 2
Hope this helps!
Comment: It's better to summarise the information from links in your answer than just post the links. That way, if the links change or break, your answer will still be useful.

How to prevent against booby-traps


Should I buy an aftermarket cooler?

Question: I need a solution for cooling the i7-4790k.
I am worried about the temperature of the CPU core going beyond 95°C (not fahrenheit).
Should I buy an aftermarket liquid cooling for my CPU for lowering the temperature or should I buy an air based cooler? The ambient temperature in the room is around 32°C - 37°C.
Comment: What temperature does the room reach without aircon? Before investing in a new cooler, I'd be inclined to replace the thermal paste with some high quality & see if it does any better - old, cracked or cheap paste is often a cause of high temps.
Comment: Thats higher than usual. There isn't really enough information though - are you running the system overclocked? Would adjusting the overclock be an option? What options have you looked at so far?
Comment: @JourneymanGeek - semi overclocking condition you can say .... i think the stock cooler is not up to the mark in cooling down the temps..
Comment: @Tetsujin normal temps 32 to 37 max .
Answer: From personal experience, for mid/heavy tasks, the stock cooler while it does do the job at preventing the CPU from overheating and shutting down the system (in most cases) doesn't keep it that cool.
If you really want very low temps even at high loads, I would recommend an aftermarket cooler in a heartbeat.
Comment: yeah .. somewhat heavy multi tasking .. i guess the stock cooler is not doing the job .. so is there any suggestion on best cooler for cpu like - corsair or cooler master or any ???
Comment: Well first up you need to decide whether you want air cooling or move over to liquid. Liquid tends to get EXTREME cool temps, hence why overclocks love it. The only downside is that it might not fit in some cases. Air is great because it fits almost any config, some bulky ones though might interfere with the RAM (which is why low profile RAM is a thing). Tower style coolers work real well as they go with the airflow of the overall case and some support multiple fans for increased cooling performance.
Comment: My personal preference is Corsair as I have used it in many builds and am satisfied with their cooling performance in many scenarios and build quality as well. In the end though it does come down to personal preference and price as well. Doing a quick Google on the cooler you chose for reviews on them is a good idea to get a ROUGH idea on how they preform against other coolers alike.
Comment: Alrighty then i will go for hydro cooler .. thanks for briefing me about the pros of it .. appreciate for your valuable time ! Cheers ...
Answer: just get a good fan (around 50 USD). and redo the thermal paste as suggested in the comment.
that should work in 99% of the cases
for that 1% that it doesn't work you should just replace the CPU assuming that intel's lifetime warranty will be honored where you bought it.
any hydro / nitro whatever fans are meant for non-standard use like overclocking etc.

Should I buy an aftermarket cooler?


Source that Rashi doesn't ask "why" questions

Question: I've heard it said many times regarding Chumash and Gemara that Rashi comments only when there is a technical problem with the text, and isn't offering analytic answers to "why" questions. I'm wondering if there are any Achronim who make this observation/claim explicitly. Thanks!
Comment: Maybe in כללי רש"י - Klalei Rashi, by the Lubavitcher Rebbe? See: https://hebrewbooks.org/30463 Klalei Rashi is the Rebbe's famous sefer on the principles of Rashi's commentary on the Torah.
Comment: 1) On page 67 "general principles" of the sefer כללי רש"י, the Rebbe explains that Rashi's commentary has one goal: give the peshat-meaning of a posuk, and to eliminate any difficulty that may arise for students in understanding. This is why Rashi passes over the more analytical insights. He won't give them, because Rashi tends to give commentary that a "five year old can understand", as the Rebbe writes many times.
Comment: 2) On page 75 "Rashi's way of interpretation" of the sefer כללי רש"י, the Rebbe explains that when Rashi does not point out the difficulty in great detail. He tends to just give the peshat-meaning. This maybe answers your question as to why Rashi does seem to not give answers to the "why" questions.
Comment: 3) Another reason why according to the Rebbe, Rashi does not give "why" answers, is because that sort of questions normally does not come up in a five year old studying Chumash.
Comment: Ah, Rashi, very very wise we should all learn from him. Most of the time we are asking why, is because we don't know what! Once we know what, the why falls away. Why are there mishpatim, chukim and edut, asks the first son. "What's that"? What's a mitzva? Once you know what a mitzva is, then the "chacham"'s questions all fall away (based on ma'amar of the Lubavitcher Rebbe). As for where is it stated, I don't know I've never heard it but I bet you can find everything you need in your nearest "What's bothering Rashi" sefer (see it in a lot of B"Ms)
Answer: Rashi himself wrote about his approach and stated he was only trying to explain the simple meaning of the verse, and he would quote agadda that would settle the meaning of the verse.
See for instance in Bereishis 3:8

וישמעו. יש מדרשי אגדה רבים וכבר סדרום רבותינו על מכונם בבראשית רבה (יט
ו) ובשאר מדרשות ואני לא באתי אלא לפשוטו של מקרא ולאגדה המישבת דברי
המקרא דבר דבור על אפניו.

In fact, Ramban in Noach 8:4 uses Rashi's approach as an allowance for his own attempts to explain the text without the words of Chazzal

אבל כיון שרש"י מדקדק במקומות אחרי מדרשי ההגדות וטורח לבאר פשטי המקרא
הרשה אותנו לעשות כן כי שבעים פנים לתורה (אותיות דרבי עקיבא) ומדרשים
רבים חלוקים בדברי החכמים.

And of course there is the famous Rashbam in the beginning of Vayeshev stating Rashi had intended to redo his commentary with an even stronger focus on the simple meaning.
Answer: I would like to begin with what Rashi himself says (as mentioned in the first answer). He says:

I have only come to (arrive at or help explain) pshuto shel mikra, the plain meaning of the text, and to (bring at times) the agadic works that settle the words of the Torah, each word in its place.

Rabbi Tuvia Bloy  in the sefer כללי רש"י - Klalei Rashi, the principles of Rashi, explains that the commentary of Rashi has one goal, namely: to give the peshat-meaning (simple meaning) of  a posuk. Rashi also wants to eliminate any difficulty that may arise for a student, in understanding a posuk. This is why Rashi passes over the more analytical insights. He won't give them, because Rashi tends to give commentary that a "five year old can understand", as the Rebbe writes many times.
On page 75 of sefer כללי רש"י, the author explains that in his commentary, Rashi does not tend to give answers that goes deeply, in great detail, in explaining a posuk. That is why, on Bereishis 3:8, Rashi points out that he came to explain the posuk according to the most simple meaning.
In כללי רש"י it is also explained, and it builds on the fact that Rashi writes commentary that even a "five year old" can understand, that Rashi does not answers "why" questions, because a five year old does not come up with that sort of questions (usually).
The Rebbe wrote also a sefer on Rashi and his principles. The sefer is called "Biurim L'Peirush Rashi Al Hatorah". In the introduction, the author writes:

רש"י מפרש את המקרא כך שהוא מבאר ומסלק כל קושי בפשוטו של מקרא ולפי זה רש"י עובר בשתיקה על ענין מסויים או קושי בולט כאשר פשוטם של דברים מובנים למעיין אם מידיעה טבעית וסביבתית ואם מפסוקים קודמים או פירוש קודם של רש"י
Rashi interprets the Torah in such a way that it clarifies and removes any difficulty in the simplicity of the Torah itself. According to this, Rashi passes over a certain subject if it can be understood by the simple meaning of it.

See also the Rebbe in Likkutei Sichos, vol. 5, p. 1, footnote 2, where the Rebbe explains why Rashi sometimes say "I do not know". This is explained in the answer of @Menachem on this post.


Smart Links in Objective-C

Question: I have an Objective-C application that uses WebKit for rendering and I would like a system to automatically detected the NSRanges of links and create them into the proper HTML anchor links. Currently I use a touchy regex to do this, but I am seeking a more sophisticated-like system that can tell the difference between links like http://wikipedia.org/test_(whatever) and that link being wrapped in parenthesis instead. Is there some de-facto framework I can use for Objective-C?
Answer: AutoHyperlinks does it well.

Smart Links in Objective-C


How to setup OS X Server to not to be accessed via localhost, but other different host?

Question: I have installed MAMP on my MacBook, and I use localhost to manage my website repositories. Previously once I installed OS X Server I was not able to manage my websites because there was OS X Server. Is it possible to configure OS X Server under the different name than localhost (example: osxhost)?
Comment: Looks like an [xy-problem](http://xyproblem.info/). Please mess around with MAMP but not with your system (which **IS** localhost). Use virtual hosts in MAMP, different ports for your repositories or the **integrated** dns server of OS X Server.
Answer: I think that the issue may be that both MAMP and OS X Apache (VIA the Server.app) are both listening on the default port 80. If you use SCUTIL to set the host name it will change the hostname for all servers on that Mac, I believe.
What I would do is check the settings in MAMP and make sure it is not listening on port 80 and if it is change it to something else. I believe if you restore defaults it will listen on a different port. Then you will have two independent web servers each listening on a different port. The server.app web server will listen on port 80 and MAMP on whatever port it is set to.
Now you can get to the MAMP site by adding a colon and the port number after localhost. Assuming MAMP is set to port 8080 it would look like this:
http://localhost:8080
and for the server.app server instance:
http://localhost
If you don't specify a port, it defaults to port 80.
Answer: maybe this command can help you: scutil –setHostName <new hostname>
source: krypted


Rip audio DVD on Ubuntu?

Question: Is there a way to rip audio DVD into 24bit AIFF or ALAC files on Ubuntu?
Comment: Does this answer your question? [How do I rip audio from a DVD?](https://askubuntu.com/questions/24326/how-do-i-rip-audio-from-a-dvd)
Answer: This works for mp3 files by my understanding but could be useful:
Pop in your DVD of choice and inspect the disc using dvdrip, Mplayer, VLC or something else of your liking.

Scan the disc TOC for title, chapter, and audio track numbers using the utilities from the transcode package; note the dvd device can be a real dvd device or the directory where you copied the VOB files:
Issue Following command:
$ tcprobe -i /dev/dvdrw1

This should be the output (or something like it)
[tcprobe] DVD image/device
(dvd_reader.c) mpeg2 ntsc 16:9 only letterboxed U0 720x480 video
(dvd_reader.c) lpcm en 16bit 48kHz 2Ch
(dvd_reader.c) ac3 en drc 48kHz 6Ch
(dvd_reader.c) subtitle 00=
(dvd_reader.c) DVD title 1/2: 16 chapter(s), 1 angle(s), title set 1
(dvd_reader.c) title playback time: 01:54:21.07  6862 sec
(dvd_reader.c) [Chapter 01] 00:00:00.000 , block from 0 to 293870
(dvd_reader.c) [Chapter 02] 00:09:04.367 , block from 293871 to 532255
[...]
(dvd_reader.c) [Chapter 15] 01:43:07.832 , block from 3340117 to 3703349
(dvd_reader.c) [Chapter 16] 01:54:20.832 , block from 3703350 to 3703357
[tcprobe] summary for /dev/dvdrw1, (*) = not default, 0 = not detected
import frame size: -g 720x480 [720x576] (*)
aspect ratio: 16:9 (*)
frame rate: -f 23.976 [25.000] frc=1 (*)
audio track: -a 0 [0] -e 48000,16,2 [48000,16,2] -n 0x10001 [0x2000] (*)
audio track: -a 1 [0] -e 48000,16,2 [48000,16,2] -n 0x2000 [0x2000]
[tcprobe] V: 164524 frames, 6862 sec @ 23.976 fps
[tcprobe] A: 107.22 MB @ 128 kbps
[...]

Note, the important info above is:

Which title has all the chapters and how many
Which audio tracks are which format

Typical music DVDs seem to have at least one LPCM stereo track and one AC3 surround track, and you'll generally want the PCM stereo track (although transcode will automatically convert the surround track if you want). You just have to specify which title, chapter(s), and audio track you want.
Scan the desired audio track for the recommended scale parameter; if you go above this value you run the risk of clipping the signal, but if you don't scale at all it might not sound very loud compared to other mp3s:
$ tccat -T 1,1,1 -i /dev/dvdrw1 -t dvd -a 0 -L -d 2 | tcextract -t vob -x pcm | tcscan -x pcm -d 1

The above command grabs the first title,chapter,angle with the -T parameter, from the dvd drive (with the -i parameter, which could also be a directory with VOB files). The -a parameter asks for track 0 (the linear PCM stereo track) while the -L parameter loops through all the chapters, and -d increases the verbosity of the output. This gets piped to the tcextract command which looks for a pcm stream (note this parameter would be ac3 for the surround track 1). This in turn gets piped to tcscan, which scans the pcm data and will spit out the proper normalize value for the given audio track (or the whole disc). Without looping through all the chapters, the output from scanning just the first chapter looks like this:
$ tccat -T 1,1,1 -i /dev/dvdrw1 -t dvd -a 0 -d 2 | tcextract -t vob -x pcm | tcscan -x pcm -d 1 T=3 1 1 1 1
(dvd_reader.c) DVD title 1: 16 chapter(s), 1 angle(s)
(dvd_reader.c) DVD playback time: 01:54:21.07
[tccat] (pid=12865) processing chapter (1/16)
(iodump.c) PAL DVD image/device
[tcscan] audio frames=13620.67, estimated clip length=544.83 seconds
[tcscan] (min/max) amplitude=(-0.996/0.996), suggested volume rescale=1.004
[tcscan] V: 13620 frames, 544 sec @ 25.000 fps
[tcscan] A: 8.50 MB @ 128 kbps
[tcscan] CD:  650 MB | V:  641.5 MB @ 9892.1 kbps
[tcscan] CD:  700 MB | V:  691.5 MB @ 10663.1 kbps
[tcscan] CD: 1300 MB | V: 1291.5 MB @ 19915.2 kbps
[tcscan] CD: 1400 MB | V: 1391.5 MB @ 21457.3 kbps

The rescale value in this case may seem rather low at only 1.004, but each disc is different, so it's worth doing this step in the vast majority of cases. Make sure to scan all the chapters, and we'll use the suggested volume rescale value in the actual transcode command below.
Now we can actually do the ripping, transcoding, and audio encoding all in one command, at least for mp3 output:
$ transcode -i /dev/dvdrw1 -x null,auto --no_split -T 1,-1 -s 1.004 -a 0 -y null,raw -m zappa_plays_zappa.mp3

Source with extra tips and tricks.
Comment: One thing first some audio DVDs also have DTS tracks but no LPCM, You may want to use that track over AC3. Now, may be I got it wrong, but by volume rescaling you are changing the loudness of the audio signal? Wouldn't adding [replaygain](http://en.wikipedia.org/wiki/Loudness_war#Replay_volume_normalisation) metadata be preferable (when encoding to lossless)?

Rip audio DVD on Ubuntu?


Keyboard and touch pad is not working on a Dell XPS 15z

Question: I am new linux user, I dont anything about how linux works, i am working on that, but mean while, i installed ubuntu on my Dell xps 15z, it works fine, except for the keyboard and the touch pad mouse. I searched for the solution but no success, please anyone have solution for this, I am very excited about linux, it very beautiful, very user friendly, I want to replace my windows with it.
Ps. Please be specific in your answer 'couse i dont know anything about linux, keep in my I am a very new user.
Answer: I have a XPS 15z too and I will tell you what I did on my xps. First, about the keyboard i don't know what happend with yours, on my notebook it works very well, i think that you will have to reinstall ubuntu to fix this.
But for the touchpad has a simple solution, you will open the terminal (ctrl+alt+T), type sudo gedit /etc/rc.local and edit the file wich opened. Before the line exit 0 you will add the following lines:
sudo modprobe -r psmouse
sudo modprobe psmouse proto=imps

Save the file and reboot the computer, i believe after this the touchpad will work. Another thing is about the videocard, it not works in ubuntu, i try so many solutions but anyone works.
I hope i could help you, sorry about my "english', its not my native language.
Comment: Thanks for the quick answer, I tried this but no luck, may be it is a problem with my installation, I will try reinstallation, hope it orks this time.
Comment: I just reinstalled Ubuntu, and applied your commands, now it is not working, but when I close the laptops lid and open it after a while, the touch pad and the keyboard will work, I don't know what is the problem, but right now it is better than nothing, if you know how to fix this i will appreciate it, Thanks again.
Answer: I've got DELL XPS 15z too, and I just installed ubuntu 12.04.
About videocard, I install Bumblebee with this commands :
sudo add-apt-repository ppa:bumblebee/stable

Then, I reloaded with :
sudo apt-get update && sudo apt-get upgrade

Just to be sure the system was up to date, and I installed :
sudo apt-get install bumblebee bumblebee-nvidia

One more thing to do :
sudo usermod -a -G bumblebee $USER

Where $USER is your username. This is to allow you to choose the videocard later.
Now restart your laptop, and enjoy ! To test it, that's very simple : try this to command lines :
glxspheres
optirun glxspheres

And see ! for me in the first case I have 1 to 2 fps, and in the second case I have more than 150 fps. So if you need to use the nvidia card, just add "optirun" at the beginnin of your software launcher.
Answer: About keyboard and touchpad, I had the same problem you have, I mean : keyboard was working on grub loading page, but not after, on the login shell, and the touchpad was not working too. It take 5 minutes to do it.
I solve the problem by adding acpi=noirq at the end of the boot line.
The way I did the modifications was this :
1/ During the first boot, I press [e] when I was on the grub loading page, then I gone to the begin of the last line and I came back by the left arrow. Then I just added there :
acpi=noirq

But take care, maybe you have qwerty keyboard instead  of azerty one (like me) so press [q] instead of [a]...
Then, press [ctrl]+[x] to execute this command line.
2/ Now you should be able to log in.
3/ To keep this modification once for all, you should edit the grub command. Execute this in a terminal :
sudo gedit /etc/default/grub

And modify the line :
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

It to obtain this line :
GRUB_CMDLINE_LINUX_DEFAULT="acpi=noirq quiet splash"

Then, save, close, and back in the terminal, execute :
sudo update-grub

Now restart your computer, and all should be great... See above my post for the videocard... Enjoy !
Answer: When i was using ubuntu 11.10 i did almost like this you did. Now on 12.04 i didin't do anything yet, i'm still look for something wich make my HDMI works, did your HDMI work?
When i using 11.10 i found the solution on post #118 of this link http://ubuntuforums.org/showthread.php?t=1776254&page=12
an then i turned off my videocard, as it did not work, at least the autonomy of my battery increased double.
Thanks man
Comment: HDMI is not working for me as well, but actually I do not need that, but you can use an adapter for the mini-HDMI to HDMI, it will be working that way, I did not try this but I so it some where, I do not remember.
Answer: May this help you, open your terminal and type:
sudo gedit /etc/default/grub

updating the GRUB_CMDLINE_LINUX_DEFAULT line to:
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash i8042.reset i8042.nomux"

Don't forget to save and close, go back in the terminal run sudo update-grub
Source


Can we be really confident about confidence intervals?

Question: I created a population of a normally distributed value. Then I pulled 100 000 samples out of it. For each of them I calculated 95% confidence z-interval. I expected to see that at least 95% of intervals would contain a population mean, but in fact only about 94% did. I tried this many times, and there was 94% again and again. I also tried t-intervals with the same result. How can it be explained?
Comment: Just a note: in practice, a method that claims 95% confidence but achieves 94% would be, in my opinion, **great**. This is because all models have a assumptions required to achieve this 95% level. The question is not whether your data meets these assumptions, but how badly it fails these assumptions. If these assumptions are only mildly inaccurate (or, moreover, breaking these assumptions only mildly affects your inference), maybe your method results in 93% true confidence level. If these assumptions are terrible, maybe you have 63% true confidence level.
Comment: I am unaware of any authoritative reference that claims it *does* give a 95% confidence interval.  It's only an approximation that was superseded when  William Gosset proposed using the Student t distribution in a 1908 paper.
Comment: The method you are using doesn't actually achieve 95% confidence.  Use the correct method, which employs the Student t distribution.  You will definitely *not* get the same result: if you do, there must be an error in the calculation.
Comment: @whuber You were right, I've tried t-intervals from Scipy and they are correct. But why that first method doesn't achieve 95% confidence?
Comment: @whuber Thank you! Your answers are great as always.
Answer: The zconfint() function takes its critical values from the standard normal distribution, instead of from the $t$ distribution (which is appropriate for small samples such as yours). The normal critical values tend to be smaller, which yields narrower confidence intervals, and explains why your intervals seem to succeed in covering less frequently. If you increase the size argument from 30 to something like 300 then you should see coverage closer to (but still slightly less than) 0.95.
If you really want to construct a $t$ confidence interval, you should create a DescrStatsW object and call the tconfint_mean() function:
import numpy as np
from statsmodels.stats.weightstats import DescrStatsW

pop = np.random.randn(1000000)

true = 0.
mean = pop.mean()
nsim = 10000
for i in range(nsim):
    sample = np.random.choice(pop, size=30)
    d = DescrStatsW(sample)
    interval = d.tconfint_mean()
    if interval[0] <= mean <= interval[1]:
        true += 1

print true/nsim


Is discussing the meaning of terms as it applies to the workplace off-topic?

Question: This recent post I made was found to be off-topic.  In my mind, the meaning of many terms is intimately connected to the context in which they are expressed.  I asked for help validating my intuition that workplace bullying is not equivalent to making demands or giving an ultimatum.  It is important to know what workplace bullying is vs. the normal processes organizations go through to hold employees accountable.  I think this would be an entirely relevant topic for discussion.
Answer: Your question was not closed because it asked about the meaning of a term. Your question was closed because it was just story about your situation and didn't really ask much of a question. Your post basically amounted to "Look at this thing my boss did! Isn't that weird?" You want us to validate that you are right and your boss is wrong.
As the close reason cited, Real questions have answers. Instead of asking a question which invites answers like "Yeah man, that's weird," it's better to ask a question that has a specific goal in mind. You could have asked, "I know my email was unprofessional. How should I have better handled it?" Or "I'm being accused of bullying behavior. How should I respond?"
Additionally, your question about the definition of bullying and whether a bully always needs to be in a place of power is not specific to the workplace. It is really a question about the meaning of a word and whether your boss used it correctly or not. That is a question better suited for sites like the English SE, though you would need to cut out a lot of the backstory before it would be appropriate for that site as well.
Comment: And as to your deleted comment, yes, sometimes the Workplace can be perceived as unwelcoming. Even more-so when some of us "higher-power" users don't always have the energy to kindly explain to the dozens of off-topic questions a day from new users, and instead just turn to being straightforward and possibly blunt. There's been [some discussion](http://meta.workplace.stackexchange.com/questions/3549/is-the-workplace-unwelcoming) on this already.
Comment: @mrsuttonsaiditfirst "Is delivering an ultimatum in this context bullying as we normally understand bullying in a workplace?" Even that wording is a much clearer and answerable question. I still think it would be off-topic, because answers would be too opinion-based and it would invite a discussion. And in fact it would be an interesting discussion, but [Stack Exchange isn't about discussions](http://meta.workplace.stackexchange.com/a/3597/16983), it's about concrete questions and answers.
Comment: Speaking to the community to validate your own opinion usually results in a bad question, precisely because it's about opinion.
Comment: Thanks for the clarification.  I apologize for my first comment.  I deleted it.  In my mind, these rigid definitions and proscriptive requirements are not conducive to welcoming people into the online community.  On the other hand, I do understand the need to maintain focus on the goals of the community.  In my mind, i did ask a question with a real answer in my mind.  Is delivering an ultimatum in this context bullying as we normally understand bullying in a workplace?  If this is not the forum discussing that, that is OK.
Comment: I appreciate the ongoing dialog and openness to it.  I'm aligned with an epistemological tradition that knowledge is not opinion.  However, I'm also in a tradition that acknowledges the possibility of error (a form of fallibilism).  The meaning of words in various contexts is an extremely challenging area.  I was appealing to this community to validate my intuitions about bullying in a workplace context.  Please don't take this as an attempt to win favor or anything else.  I respect the authority of users who are administering the community to define the boundaries.
Answer: The reason your question was closed is actually revealed by the way you started this one. You said "The recent post..." It was wasn't supposed to be a post, it was supposed to be a question.
If that wasn't enough of a clue you ended this question with the phrase "I think this would be an entirely relevant topic for discussion." again the purpose of the site is to ask questions, not to have discussions.
Answer: You wrote "The main thing I really want to know is if anyone finds this a little humorous."
So perhaps asking "Am I funny?" is not considered appropriate at The Workplace?
Comment: We dont like fun here... https://blog.stackoverflow.com/2010/01/stack-overflow-where-we-hate-fun/
Comment: Which question are you looking at? This user's only question says nothing about something being humorous.
Comment: It was in one of the comments.
Comment: Yes, I did do that.  I realize now it was my mistake.  This is probably not the best forum for this type of discussion.


What do I use the coffee beans for?

Question: In "Animal Crossing: New Leaf," the owner of Roost Cafe lets you work part-time and gives you some beans, according on how well you served the customers. The problem is, I don't know how to use them! Can someone help?
Answer: The coffee beans are completely useless except for selling purposes. You do also get a coffee maker from Brewster, but it is purely for decoration.
All of the beans can be sold for up to four times more (minus one) via the flea market than to Reese - for example, the superb beans fetch 2000 with Reese and up to 7999 on the flea market.
Answer: They are useless unless you sell them. I recommend you selling them on the flea market,you get more bells! I have tried it myself.
Answer: Go to        http://www.thonky.com/animal-crossing-new-leaf/the-roost-cafe/    they give you a whole list of how to make coffee for all customers, including special ones like Isabelle and DJ KK. If you get all customer's orders right Brewster will give you Superb Coffee Beans, the best ones he stocks. They are of course, only given to you to be sold, and are basicly purposeless. Brewster will occasionally give you special furniture that looks like you could actually make your own coffee with the beans, but they are only for displaying.

What do I use the coffee beans for?


Stairs railing restoration

Question: I have noticed that some of my stair railing coating has been chipping off, clearly due to wear and tear uses. I have an elderly person living in the house and has to hold the railing right to use stair. Is there Polish or coating that I can use to restore the look of it? Attaching pictures for the reference. First time homeowner in the States so really appreciate your help. Thank you so much in advanced.
Answer: Yes, sand it down and re-apply a suitable finish.
Looks like it is the damage from a ring worn by someone though, given how is is on the "corner"...
Comment: or until you are ready to sand it down, find a varathane and just feather it into the areas that are most chipped.

Stairs railing restoration


Hello Word Device Tree Based device driver

Question: I have read and almost gone through all the linux kernel documentation on the device tree and device tree overlays.I am not able to understand if we have to create a new entree in the device tree of the platform or to create a new overlay for the device for a new driver based on device tree.
I am looking for a simple led glowing driver example where led is connected to GPIO pin and its configuration is mentioned in the device tree overlay or device tree fragment on the board's platform.How can it be build/pushed and tested using the user space application.
Comment: I had a similar issue and solved it with the example of `kernel_src/drivers/uio/uio_pdrv_genirq.c`. The information from device tree is received through the `of` functions (Open Firmware). You need a Kernel stub as well, where I recommend `Hans J. Koch: Userspace I/O drivers in a realtime context` (generally this author wrote several papers about UIO).
Comment: can you please post the dts file content  you inserted into the platfrom dtsi?and how did you do and build/test it?
Comment: I just used a custom dtsi with custom compatible and the appropriate reg properties. In the device driver I fetched the compaitble in the `struct of_device_id`
Comment: can you please elaborate with the example in the answer section ?About the dtsi file as well?
Comment: I think my knowledge is too vague and I don't know if it will help you.
Comment: Still , no harm in sharing ! I will use my discretion :) ! Thanks in advance !
Answer:
I created a custom device in my device tree:
my_device@ffdf0000 {
    compatible = "my_driver";
    reg = <0xffdf0000 0x1000>
    /*
     * reg = address of device and size
     * (Minimum is System's Pagesize = 0x1000 Byte in my case
     */
}

I wrote a Kernel stub for this Device:
(Here I took kernel_src/drivers/uio/uio_pdrv_genirq.c and Hans J. Koch: Userspace I/O drivers in a realtime context (device driver tutorial) as basis.)
This stub has following two structs:
The of_device_id struct:
static struct of_device_id my_match_table[] = {
     {
             .compatible = "my_driver",
     },
     {0}
};
MODULE_DEVICE_TABLE(of, my_match_table);

and the driver struct itself:
static struct platform_driver my_platform_driver = {
        .probe = my_probe,
        .remove = my_remove,
        .driver = {
                .name = "my_driver",
                .owner = THIS_MODULE,
                .of_match_table = of_match_ptr(my_match_table),
        },
};

Now I have access to the properties of the device tree in my probe function:
static int my_probe(struct platform_device *dev)
{
        struct uio_info *uioinfo;
        struct resource *r = &dev->resource[0];
        [...]
        uioinfo->name = dev->dev.of_node->name /* name from device tree: "my_device" */
        uioinfo->mem[0].addr = r->start; /* device address from device tree */
        uioinfo->mem[0].size = resource_size(r); /* size from device tree */
        [...]
}

When there is a match in compatible with both the kernel stub's entry and the device tree, the probe function is called.
Comment: please pm me at raulpblooper at the rate gmail dot com with the subject line  your user name : h0ch5tr4355 : Device tree.I want to discuss more on it.Thankss for sharing the example !!Waiting for your mail.Thanks once again !
Comment: I'm a newbie on device tree as well. I just wonder how you got the address of the `reg` property?. Or can I set an arbitrary address?
Answer: Use QEMU with a minimal custom hardware device
I recommend you code up your own minimal platform device, to also control the hardware and have a full understanding.
I have provided a full runnable Buildroot QEMU example with source code on GitHub as detailed on this answer: How to program Linux .dts device tree files?
The example is also documented on the GitHub repository.


Noise Characterization

Question: I am working on characterization of noise in an experimental signal from an accelerometer, mounted on a beam. Normally, white gaussian noise is considered by several researchers to add noise in the simulated model. I want to find out, what is the noise type in real scenarios, whether it is gaussian or non-gaussian.
Comment: Could you please review my answer? If it fits you, could you mark it?
Answer: There are 2 properties which are important to know about your noise:

Its Self Correlation
What usually called Auto Correlation. This will tell you the relation between 2 noise samples which are apart (On time) from each other (I'm assuming the signal is stationary, namely its properties doesn't change over time).
Best thing to hope for is White Noise.
Its Distribution
Sometimes, in order to be able to do estimations of the data one should also know the distribution of the noise. The most wide spread model is Gaussian Noise as you wrote. Yet on Image Processing it could be Poisson Noise.

If you have access to "Pure" noise samples analyzing those properties of the noise is really easy.
For the first you just calculate the Auto Correlation Function.
For testing Gaussianity / Normality Test (Reference - Tests of Gaussianity) things gets a little tricky.
As you can see in the Wikipedia Page of Normality there are many tests.
Though poor man's (Yet effective) test would be just looking at the Empiric Histogram and compare it to the model (Curve of Normal PDF based on the data Mean and Variance).

Noise Characterization