"be going to" in Future Perfect

Question: I can say:

By that time, I will have taken ten tests.

I want to know, can I in Present Perfect substitute will with be going to?

By that time, I am going to have taken ten tests.
Answer: There is nothing to prohibit this construction, and if you use it it will neither raise eyebrows nor be misunderstood. Here are a couple of examples:

A lot of people graduating with an MPH are going to have taken the same classes, so you'll have an advantage if you can show that you have been responsible for data analysis.  — Beth Seltzer, 101 Careers in Public Health, 2010
And if, like Nick, you were in the front line and not merely a blanket stacker stuck back at base, then of course it's going to have taken its toll. —Jan Evans, A Maid of Kent: A Novel Set Against the Backdrop of the Falklands War, 2011

But this is a very rare usage. Outside of formal texts on linguistics, those are the only two instances of "going to have taken" actually reported by Google Books.
If you run across it, you will know what it means; but there is no need to incorporate it in your working vocabulary.
Answer: The "be going to do something" construction is similar to "will do something" for the future tense, and thus they both can be used with non-perfect (to do) and perfect (to have done) infinitives.
For example, the sentences

By next June I will have gone to Spain

and

By next June I am going to have gone to Spain

will express the same idea. So they may be regarded as interchangeable, and if there is any difference between them, it would lie solely in choosing between "I will" and "I am going to", depending on the reasons you have in mind in favor of either the former or the latter.
At the same time, you should bear in mind that "will have finished" is undoubtedly more economical and smooth, so it's up to you to decide whether there's any profit in using the longer version.
In my opinion, similar to that of @StoneyB's, simply knowing that such a construction is grammatically valid  and recognizing it in texts (should you come upon it again), would be just about enough for an advanced ESL learner.
Answer: When you use the future perfect tense, you use 'will' only, and not 'be going to'.
That is a grammatical rule, so no further explanation is necessary.
Comment: I think this answer is going to be downvoted.

"be going to" in Future Perfect


How to set a dateTimePicker value to DateTime.MaxValue

Question: This generates an error at runtime:
dateTimePicker.Value = DateTime.MaxValue;

Answer: You can't.
The maximum date supported by DateTimePicker is DateTimePicker.MaximumDateTime, which is 12/31/9998; DateTime.MaxValue is 12/31/9999 23:59:59, which is one year and one day later.
Can you use that DateTimePicker.MaximumDateTime instead of DateTime.MaxValue?
Comment: Any idea why these are different? I couldn't find any explanation of it on Google.
Comment: Sure I can now that I know :)
Comment: I don't know; I took a quick look through the source and found no obvious reason.
Comment: Perhaps it is because one might want to some "math" with DateTime and possibly end up with something out of range of the 2 inputs.
Answer: You need to use the DateTimePicker.MaximumDateTime property. The maximum value allowable for the datetime picker is 31/12/9998, as represented by DateTimePicker.MaximumDateTime. Whereas the value of DateTime.MaxValue is 31/12/9999.
Answer: Yes you can, but it is quite dirty (use it at your own risk). Basically, it overwrites the MaxValue defined in the DateTimePicker with the MaxValue from the DateTime object.
Paste this code into the Main (or any method run during startup):
var dtpType = typeof(DateTimePicker);
var field = dtpType.GetField("MaxDateTime", BindingFlags.Public | BindingFlags.Static);
if (field != null)
{
    field.SetValue(new DateTimePicker(), DateTime.MaxValue);
}

Answer: Perhaps this is helpful:

The value of this constant is
  equivalent to 23:59:59.9999999,
  December 31, 9999, exactly one
  100-nanosecond tick before 00:00:00,
  January 1, 10000.
Some calendars, such as the
  UmAlQuraCalendar, support an upper
  date range that is earlier than
  MaxValue. In these cases, trying to
  access MaxValue in variable
  assignments or formatting and parsing
  operations can throw an
  ArgumentOutOfRangeException. Rather
  than retrieving the value of
  DateTime..::.MaxValue, you can
  retrieve the value of the specified
  culture's latest valid date value from
  the
  System.Globalization.CultureInfo.DateTimeFormat.Calendar.MaxSupportedDateTime
  property.

blatantly copied from msdn


How many submissions a month per Cognito free tier account?

Question: How many submissions a month are we able to have with a free Cognito account? What is the storage limit and what is actually stored? Is that the amount of forms and data collected? Or would that only be uploads?
Answer: I am a developer for Cognito Forms. Currently, we have unlimited forms, unlimited fields, unlimited entries and unlimited storage. We store all of your submission data, including any uploads.
However, at some point next year we will roll out some tiered data and entry plans, which you can find out more about in our blog post.
We wanted to make our pricing very simple and representative of how much people actually use their forms. With tiered plans, free users will be limited to 100 MB of data and 500 entries per month. The first paid tier (at just $5 per month) will give them 1 GB of data and 5,000 entries per month – ten times more than the free plan.
All plans, however, will always have unlimited forms and unlimited fields.


Why is plastic deformation a non-linearity if I am using Bilinear hardening to model it in FEA?

Question: Attached you may find a picture for isotropic bilinear hardening up until the ultimate tensile strength. The first line is the elastic region while the second one is plastic. I couldn't understand that why is plasticity even a non-linearity in FEA? I mean if I just consider the graph below, then a point in a FEA model will just move over this graph only. If it switches from first line to the other, then there is just a change in the elastic modulus. If I am conducting a geometrically linear analysis, then how could inputting a material plasticity model, like the one showed below, make the analysis still be non-linear?
Comment: Err its clearly nonlinear on account of it having two line segments. Everything that is not a single line in its whole domain is not linear. You need a whole different class of solvers to solve nonlinear equations because you now need to keep track of the actual path that was taken for the solution whereas for a linear solution is guaranteed to be a simple solution. You can just disregard the path and jump directly to the solution.
Comment: "LInear" means "if you double the loads, you get exactly twice the displacements". It should be obvious this is not true for your stress-strain curve. Also, in a structure with this type of material behavior and redundant load paths, there may not be a *unique* solution for every possible set of applied loads.
Comment: Understood. Makes sense. Thanks, to both of you.
Comment: I am curious about where you get this diagram, can you please provide the source? Thanks.
Answer: In the plastic range, the stress-strain relationship is non-linear as shown in the graph below. With consideration of geometric changes after yield, the true stress-strain curve (dotted line in the graph) shall be used instead of the normal curve, and non-linearity needs to be considered in the analysis.

Note: Due to the shrinking of section area and the ignored effect of developed elongation to further elongation, true stress and strain are different from engineering stress and strain.
$\delta_t = \delta(1 + \epsilon)$, and
$\epsilon_t = ln(1 + \epsilon)$
Comment: The question has nothing to do with plastic behaviour. The stress-strain curve in the OP's example is completely reversible. A real material showing a similar effect, but with the graph curving the other way, is rubber.
Comment: @alephzero On your mentioning of "rubber material", please read this https://www.quora.com/What-does-the-stress-vs-strain-curve-for-rubber-look-like.
Comment: For the downvoters, please indicate your dissent for a material that possesses linear elastic behavior up to the yield and will have some degree of permanent distortion upon unloading after stressed beyond the yield point (non-linear). And please provide the type of material that will deform linearly after yield. Thanks.
Comment: @alephzero I read the OP's question several times and failed to understand why a straight line was shown after the yield point unless it was an idealization for the convenience of analysis (I doubt). Also, in the opening, the OP stated "...a picture for isotropic bilinear hardening up until the ultimate tensile strength. The first line is the elastic region while the second one is plastic....", why is "plastic" if the stress and strain is linear within that range?
Comment: I guess I couldn't get a straight answer then. So disappointing.


Take screenshot of wpf popup window

Question: I try to take a screenshot of an application writen in WPF and the application is not captured, must I use a special tool to take the screenshot?
Answer: You can use RenderTargetBitmap to generate an image from your WPF control.
<code>    public const int IMAGE_DPI = 96;

    public Image GenerateImage(T control)
        where T : Control, new()
    {
        Size size = RetrieveDesiredSize(control);

        Rect rect = new Rect(0, 0, size.Width, size.Height);

        RenderTargetBitmap rtb = new RenderTargetBitmap((int)size.Width, (int)size.Height, IMAGE_DPI, IMAGE_DPI, PixelFormats.Pbgra32);

        control.Arrange(rect); //Let the control arrange itself inside your Rectangle
        rtb.Render(control); //Render the control on the RenderTargetBitmap

        //Now encode and convert to a gdi+ Image object
        PngBitmapEncoder png = new PngBitmapEncoder();
        png.Frames.Add(BitmapFrame.Create(rtb));
        using (MemoryStream stream = new MemoryStream())
        {
            png.Save(stream);
            return Image.FromStream(stream);
        }
    }

    private Size RetrieveDesiredSize(T control)
    {
        if (Equals(control.Width, double.NaN) || Equals(control.Height, double.NaN))
        {
            //Make sure the control has measured first:
            control.Measure(new Size(double.MaxValue, double.MaxValue));

            return control.DesiredSize;
        }

        return new Size(control.Width, control.Height);
    }
</code>
Note that this will generate a PNG image ;) If you wish to store it as a JPEG, I suggest you use another encoder :)
<code>Image image = GenerateImage(gridControl);
image.Save("mygrid.png");
</code>
Answer: You can simply press PrtScr button (windows will copy whole descktop image to buffer), then paste it in Power Point and crop if you like.
Answer: I'm having the same issue, I need to take screenshots to document my tests but can't seem to get there.
The Window in question is a Borderless modal Window with rounded corners / transparency allowed. Here's my report:

HP Quality Center's Screenshot tool doesn't recognize it as a window and thus takes its screenshots as if the window weren't there.
SnagIt utilizes a keycombo to enter the capture mode. Once stroke is hit, the popup vanishes. It reappears after the capture has ended.
Standard Windows capture works OK (Alt + Prt Scr) and captures the window as it was intended to be captured.

Next thing I tried was capturing the window with an opened dropdownlist. None of the approaches mentioned above seems to work (the last approach captures the Window the same way it did before, without the open dropdown).
As far as I have understood all the talk correctly, the only thing you can do is implement this into the applications...

Take screenshot of wpf popup window


What is a "pedagogical reflection" in a teaching statement?

Question: I am in the process of applying for an academic position in Europe. They have asked for a short pedagogical reflection in teaching statement, but I do not understand that. In the college that I am working now they have designed an online questionnaire to get students' feedback. The report is not available for public and it is in fact an internal report. Can I just copy that tables including the results? If so, how can the hiring committee validate that reports and results? Or they just rely on what I have written?
Answer: I would guess that they are asking more about your teaching philosophy than about feedback per se. Stating that you get good student feedback is fine, but I'd think they want more.
How do you interact with students? What sorts of exercises do you use? What is your grading philosophy (perhaps)? What do you expect outside of class? How do you manage questions in lecture? What sorts of materials do you provide?
But the above are just elements of a general teaching philosophy. For some universities teaching is a much more important element of the job than in others. Perhaps that is the case here.
Comment: Good answer, only want to add: there are lots of resources for writing teaching statements. Here's [one](https://cft.vanderbilt.edu/guides-sub-pages/teaching-statements/).
Comment: Think about how you teach. Are the classes you run _Socratic_ (you ask questions, trying to force the answers to the points you want to make)? Do you pick up a piece of chaulk when you walk in the door, and then write on the board for 55 minutes? Can every test question be found in a chapter you assigned for reading (or in the stuff you wrote on the board)? Do you value "the points I made in class" or a more general understanding of the subject? Do you believe in closed or open book tests? Caveat: I'm not a teacher
Answer: Pedagogical reflection means to critically review your teaching methods in order to improve upon them. What worked? What didn't? How can you improve?
Here's link to a recent paper from the Journal of Effective Teaching in Higher Education (vol. 4(1)) by Emily E. Virtue, "Pedagogical Reflection: Demonstrating the Value of Introspection."
DOI: https://doi.org/10.36021/jethe.v4i1.213
Note: This was found via a Google search using the phrase 'pedagogical reflection'


Standardizing data (mean = 0, SD = 1) while avoiding look-ahead bias

Question: I'm running a predictive model. Over 60 months, every month I get a median value from a data set. To avoid look-ahead bias, I can only use the current and prior median values found up until this current month. I need to standardise the current median value every month to have a mean = 0 and std.dev = 1. The formula I use in excel is: =IFERROR((A1-AVERAGE(A$1:A1))/STDEV.P(A$1:N1),0)
Since the average and stdev values used in the formula are not based on the entire sample of 60 months' data, the standardisation is not perfect. But how else can this be achieved if look-ahead bias is to be avoided?
Answer: I'm not an expert in Excel but it seems that if you establish a window of time across a fixed number of past periods -- e.g., one quarter or one year (3 and 12 periods, respectively) -- and roll that forward as a function of the current period, then you would have something that does not use the full 60 months of information. In initializing this "time window," you can choose to lose the first x months of your data or, if you choose to retain these "initialization" periods, recognize that those first months will likely have higher volatility.
Another suggestion, since you are analyzing median values, why use mean standard deviation? This paper on outlier detection proposes using the median absolute deviation (MAD) instead:  http://www.sciencedirect.com/science/article/pii/S0022103113000668
As a moderator to this site noted on an earlier thread, it's a nonstandard approach. But at least it's consistent with the median values you're working with whereas mean standardizing is not.
Sorry @sjoerd, your answer was posted as I was writing mine...
Comment: Thanks for suggesting MAD. I will implement and take note of the improvement. As mentioned below, I do not use a fixed window, but grow the window as more data becomes available. Should I use a fixed window and roll it forward instead?
Comment: If I understand you correctly by *growing* the window, you mean that with each successive period, you simply add another period to your window. So, if you're predicting time *t*, your window would be from 0 to t-1, and at time *t+1*, your window would be *0* to *t* and so on? Yeah, I wouldn't do that and would recommend including a fixed number of time periods in your window for each new *t*.
Comment: Correct, I did a few test runs - fixed period works much better. That clears it up. Thanks!
Comment: @nelus Thanks for the "check" for a correct answer. How about a +1 too? (I'm new to CV and trying to amass points.)
Comment: Sure. I hope it worked. Doesn't show publicly yet.
Comment: @nelus Thanks! It will appear eventually...once you get enough points!
Answer: An alternative to your approach is to keep a rolling mean and standard deviation in memory which you use to update your mean and standard deviation over time as more information becomes available.
The advantage of this is that it may reduce fluctuations in the mean and standard deviation as more information becomes available, and therefore may better allow your model to account for this aspect.
Have a look at http://jonisalonen.com/2014/efficient-and-accurate-rolling-standard-deviation/
Comment: thanks for suggestion. I currently do update mean and std.dev as more data becomes available. I do not however use a rolling approach with fixed N. My N is incremented as more data becomes available. i.e.(x0,…,xN−1) to (x0,…,xN). and not (x0,…,xN−1) to (x1,…,xN). Is there any benefit to using rolling approach with fixed N as apposed to an ever growing sample set?


How do I know when evaporative/swamp cooler pads should be replaced?

Question: This is my first experience with an evaporative cooler because we just moved into our house. I have no idea how long these pads have been it he cooler. We never noticed any smells come from the cooler and the cooler seemed pretty cool to us. How do I know when the pads should be replaced? My understanding is that these cardboard type ones last longer than the fiber based ones.
Answer: You're going to be up there at least twice a year, to put on and remove the jacket, so check the state of the pads each time.
You won't need to replace them every year, but treat them like any filter - if it looks dirty or clogged, it probably needs replacing.
The pads in your photo don't look bad - I'd leave them for now, and check again in Spring.
Answer: we use the same pads on our greenhouses they run all year round and last us around 5 years i find dosing periodicaly with clorine or hydrogen peroxide helps prevent alge buildup that clogs the pasageways but id your housing keeps light off the pads that should be less of a problem
Comment: Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably [take our tour](//diy.stackexchange.com/tour) so you'll know how best to contribute here.


Why are the sewage pipes "backed up" if much capacity still exists?

Question: My sewage system is way in the green for capacity (76.1 needed, 123.0 capacity). Yet every now and then I get a yellow alert that I have "backed up pipes", and the Treatment Plant shows the "Sewage Problems!" icon. No problems are apparent aside from the yellow alert; the plant has never lost power, and as far as I'm aware there has never been a lack of workers. The alert stays for a few minutes and goes away on its own with no apparent cause. I've had this issue in every city once it reached a certain point. What is the deal here?
Comment: 'Rush' Hour....
Answer: I agree with Robotnik in the comments, its probably Rush hours causing this. Have another Treatment tank in the plant but keep it deactivated to save money. Then activate it when rush hour occurs. Also check the roads leading to the plant, is there no way you can create a bit of a "shortcut" for further laying areas.
Comment: By "rush hour" I presume you mean "the time of day when work shifts change and all the workers are moving between R and C/I". How is that related to water usage/sewage production?
Comment: And even if sewage production is increased during rush hour, why doesn't the demand/capacity gauge tell me so?
Comment: I found that industrial areas create more sewage that residential areas, is it not maybe in the middle of work shifts? When all the industrial areas are functioning?
Answer: If all else has failed (your roads are all connected, you've eliminated all pollution, and you have tons of free capacity) your sewage plant may be too far away (in road-driving distance). If that's the case, the buildings with the longest driving distance to your plant will not be serviced or service will be spotty. Move the plant closer along the road, or add another one nearby.


How to troubleshoot high kernel time (high network usage; high interrupts)

Question: I've noticed that I have high kernel time when doing a lot of network traffic in Linux. I also noticed that 45% of my CPU is spent doing interrupts. How can I further troubleshoot this?
Comment: Do you have a lot of firewall rules that have to be processed?
Comment: Wired or WiFi? If WiFi, is your MTU 1500, as shown by `ip link`? Your WiFi MTU should be 1492 or you'll waste time on packet fragmentation/defragmentation.
Answer: The systemtap stuff is supposed to let you drill down into the kernel, and lately also applications, for tracing, troubleshooting, and debugging. Haven't used it myself.
High interrupt traffic for high network traffic might be due to less-than-bright network card or driver, perhaps a higer-end card gives better results. The kernel's handling of networking has also improved, perhaps updating the kernel helps.
OTOH, if 50% of CPU usage goes to interrupts, and CPU utilization is 3%, there should be nothing to worry about... review the data you have (and how you collected it, what the exact meaning of the numbers is) and think it over.
In the end, the question shouldn't be "Measuring foo gives bar", but start with "Performance is bad/unacceptable, what do I need to measure to find out where the bottleneck is, so I can remove it". If that leads to the above question, fine, but then you know where you are going.


How antiviruses name malwares

Question: While analyzing a binary online through the virustotal service , I found out that different AVs named the binaries differently.For instance, for that same binary Norman named it  Obfuscated_A, Symantec named it WS.Reputation.1 and another AV named it Malware-Cryptor.General.2 .Is there any specific naming convention adopted by the AVs?
Answer: Different AV vendors use different naming conventions. Many of them describe these conventions on their websites. For example:

http://www.microsoft.com/security/portal/mmpc/shared/malwarenaming.aspx
http://www.symantec.com/security_response/virusnaming.jsp
http://www.avira.com/en/support-malware-naming-conventions

AV vendors will sometimes try to use the same names as other AV vendors for well-known malware families, but this is not guaranteed and is becoming less and less common. For example, Microsoft, Sophos, CA, and McAfee all refer to the well-known Conficker family as "Conficker", but Symantec refers to it as "Downadup".
Even when AV vendors agree on a family name, they will hardly ever be in-sync on variant names. So for example, a file detected by Microsoft as Conficker.B might be detected by CA as Conficker.C.
This is why whenever you want to refer to a specific malware variant, it's always best to give the detection name and the AV engine name. Or better yet, just give the file hash and let people look it up on a site like VirusTotal.
Comment: To add to this slightly, many AV companies directly avoid using common names/strings found in the binary as the direct name of the malware (they often use embedded strings as a starting point though), as they believe it gives the malware authors "celebrity" and they don't want to promote their work.
Answer: Something to take into consideration is generic detection names. Generic detections are designed to catch as many malware samples as possible while avoiding false positives. They can be made to trigger packers or obfuscation, unorthodox behaviors etc. While this improves coverage the end result is that you can have multiple, unrelated malware samples detected under the same name. This makes it harder to identify which specific malware you are facing. Microsoft usually does a good job of detecting samples with their specific name so I usually look at their detection name first.
In the example you give all the names are generic : Obfuscated_A probably triggers on obfuscated code, WS.Reputation.1 is most likely based on file reputation and Malware-Cryptor.General.2 probably detects a packer.
Answer: I want to add that the malware gets named after what is detected within. For example MyDoom

Schmugar chose the name after noticing the text "mydom" within a line of the program's code. He noted: "It was evident early on that this would be very big. I thought having 'doom' in the name would be appropriate." (Source: Wikipedia)

And Flamer had a lot of functions named "Flame" in it's program code.
While I was working at an anti-virus company I always had a great fun with the naming practice. The reason for the names is to make sure you are talking about the same malware (md5 hashes talk really difficult). Also to decorate the families (malware that is 'just' a bit different but mainly the same). This is why you get Conficker.A and Conficker.B (like @JasonGeffer said) . The reason Microsoft's B is Sophos A is because Microsoft found a different sample of the family first in its honeypots :)
other websites that might interest you: http://www.caro.org/ and http://www.eicar.com
Comment: it's actually rare that we pick something from the contents, because it's rare to find anything good.  Usually we just pick words out of the air - that we haven't used already, of course.
Comment: @Stolas: I guess AV researchers got burned by picking *something*. Company lore has it that at one point someone picked a word that meant something really rude in a foreign language. Everybody outside our company attributed it to a particular researcher. Until that researcher noticed the name first and informed the other (unwitting) researchers what it meant in a certain group of languages. So the more abstract, the better.
Comment: @peterferrie Funny to see that even Anti-Virus companies differ. But then again, Conficker was called Kido when I first heard of it. After I learned the entire planet it Conficker someone named it DownAUp.
Answer: Generally Antivirus companies follow the naming convention proposed by CARO (Computer Antivirus Research Organization).
A malware usually gets a name based on the strings found in it. In some cases based on Mutex/ file name/server name/registry keys and very rarely based on its action.
In some AV companies they give certain names to track the detections made by generic/ heuristic detection methods (eg:Obfuscated_A, WS.Reputation.1)
Comment: CARO -> Computer Antivirus Research Organization?
Comment: @Stolas yes you are right :)
Comment: @PalaniyappanBala: actually that's untrue. All efforts to unify the naming schemes have been busted. Those specifications of course exist, but there are too many exceptions to claim that they "follow" it. This is as much for practical reasons as for competitive ones. Disclosure: I work for an AV company myself.

How antiviruses name malwares


What all content PKCS#7 can have and what is the purpose of each?

Question: When signed data is packaged as PKCS#7,
what all content PKCS#7 could be there(Ex. certificates, signature, etc.)?
And what are the purpose of packaging all those contents?
Answer: You can embed any data within a PKCS#7/CMS structure.
The Cryptographic Message Syntax (which is the new name for PKCS#7) knows the types EnvelopedData for encrypted data and AuthenticatedData for signed/MACed data.
That way, you can create an enveloping signature, thus storing the signature and the signed data in a single file even when the format of your data does not support it.
Comment: When I sign a data and package it as PKCS#7 file, what all data should be there? and what is the reason behind it?
Comment: It it optional, if you actually do it, is up to the requirements of your application. As I wrote in my answer: You might want to do it, if you do not want to have a detached signature (a signature in a seperate file), but your file type does not allow to embed a signature directly.


Why noise canceling headphones do not attenuate the signal itself?

Question: Noise canceling headphones use a microphone to capture noise in order to cancel the same. The microphone will capture whatever acoustic signal reaches it. Since it is in the vicinity of the speaker, it must capture the sound coming from the speaker apart from the noise, particularly low frequency components. This should result in not only removal of noise but also of some portions of the signal. How it is ensured that only noise is removed?
Answer: It's not clear what you are asking.  Noise cancelling headphones measure the noise to be cancelled, then actively produce the negative of that noise at just the right volume so that the two cancel.
There is no issue of "recording" anything here.  The microphone data is used real time, with perhaps a tiny delay to account for the propagation of the waves it measured across the distance to the emitter.  The speed of sound is roughly 3 µs/mm, so even if the mic and speaker were 10 mm apart (a lot), then that would only be 30 µs of "recording" before the recorded information would be discarded.  In practise, this would only require a single sample anyway.
As for "attenuate the same", it is unclear what you are talking about.
A better answer requires a better question.
Comment: Please see the edited question, hopefully it is better now.
Answer: Consider that the noise is being 'cancelled' by your perception because of the speaker in your ear. Most headphones of this type also have some sort of material to absorb vibrations so that the microphone couldn't pick up any sound coming from the speaker.
If the microphone could somehow collect sound from the speaker, the antiphase sound through the speaker would be out of phase with the original sound that was picked up by the microphone, and the microphone would then not pick up any background sound. The computer in the headphones would not produce any antiphase sounds, then the microphone would pick up the ambient noise again in the next iteration. This would simply result in very poor quality headphones that would probably hardly cut any ambient noise at all by human perception.
That being said, the speaker in any headphone that does not have some sort of noise absorption material (passive noise cancelling) is going to be far enough away from the microphone that the microphone couldn't pick up the sound. You shouldn't be listening to anything greater than 80dB for a prolonged period of time, and the inverse square law
$$\frac{I}{{I}'}= \left ( \frac{{d}'}{d}  \right )^{2}$$
Shows pretty clearly that simply the distance between the speaker and the microphone isn't enough to reduce the dB at the microphone substantially.
Simply
It would be terrible headphone design, so they don't make them that way. They use noise absorbing material such as padding on over-ear headphones and rubber on earbuds.
Answer: Noise cancelling headphones work by measuring external nose, inverting the signal produced and adding it to the speaker output. This either produced a net effect of 'quiet' or eliminates noise from the audio feed. Separating and audio input from external noise is an inherent part of this and can be achieved through microphone placement, acoustic insulation, electronic/digital filtering or any combination of the above.
There is also the fact if the system 'knows' what the desired audio output is it can be added after any nose cancellation takes  place and it is also possible to predict what frequencies are likely to be problematical in terms of noise in advance, depending on context.
But the simple answer is that the whole system is designed so that the external noise and desired audio output are separated.
Noise cancellation tends to work less well for low and mid frequencies, apart form anything else because there is often a residual need or verbal communication and allowing audible warnings to work, especially in an industrial context. But having said that it is often high frequency noise which is most annoying and hazardous in industrial applications to there is a lot of scope for specific tuning with filters and parametric and graphic EQ especially where software allows this to adapt to ambient conditions.
Comment: Microphone placement and insulation will not keep away the low frequency components. How electronic filtering works?


Addressfield entries not showing up when entityform sends an email

Question: I have an Entityform that uses the Address Field module. Viewing a submission in the interface is fine. However, when the admin email goes out, only labels are shown; the address fields are empty. Has anyone had this problem?
Answer: This was addressed in an issue on Drupal.org. Which version of Entity2Text are you using? The fix was added to 7.x-1.0-alpha2.
Comment: I had alpha2 and just up'd to alpha3, and it's working now, all addressfield fields with data are in the email.
Comment: I'm having a similar problem with files attached via the entityform. The email contains the "Files:" label but no data follows. It would be nice to see the filename and/or Description for each file. I don't know that it's an E2T issue but thought I'd mention it. BTW, I forgot to say THANKS!


Is there any way to know about fake reputation?

Question: Let suppose if someone has fake reputation which he has made using multiple accounts then is there any way to check for normal user? For example I'm normal user.
Comment: All reputation here is fake ...
Comment: @rene how  can you say?
Answer: No, there isn't a way for a "normal user" to check these.
Moderators have tools that give them indication of voting irregularities.
Stack Exchange employees have access to more detailed information.
Comment: Thanks for sharing knowledge...


With respect to what quantities do I vary Lagrangians in field theory?

Question: I have recently been wondering, with respect to which quantities (covariant or contravariant) one should vary QFT Lagrangians and whether there is some rule regarding this. Let me give an example which will hopefully clarify what my problem is.
Let's take the source-free EM Lagrangian:
$$
\mathcal{L}=-\frac{1}{4}F^{\mu\nu}F_{\mu\nu}
$$
One can now compute:
$$
\frac{\partial\mathcal{L}}{\partial(\partial_\mu A_\nu)}=F^{\nu\mu}\\
\frac{\partial\mathcal{L}}{\partial(\partial^\mu A^\nu)}=F_{\nu\mu}\\
\frac{\partial\mathcal{L}}{\partial(\partial^\mu A_\nu)}=F^{\nu}{}_{\mu}\\
\frac{\partial\mathcal{L}}{\partial(\partial_\mu A^\nu)}=F_{\nu}{}^{\mu}
$$
If I want to arrive at the correct equation of motion now, I have to choose $\partial _\mu$ or $\partial ^\mu$ according to how I varied $\mathcal{L}$ (btw: is "varied" the correct word here?).
My question is: is there a "correct" way to do this? Can I write the equation of motion in a way, which will work for all Lagrangians without me having to "manually" pick the $\partial$? Most textbooks seem to have:
$$
\partial_\mu \frac{\partial\mathcal{L}}{\partial(\partial_\mu \phi)}-\frac{\partial\mathcal{L}}{\partial \phi}=0
$$
The example above seems to suggest, that varying w.r.t. a covariant quantity returns a contravariant quantity so to say and vice versa. Is that true in general? I do unfortunately not have any theoretical background on this so far and am being thrown into the cold water.
Comment: Isn't the Lagrangian supposed to be of the form $\mathcal{L}(\phi,\partial_{\mu}\phi)$? In that case you see you should vary wrt. $\partial_{\mu}$
Answer: Let us suppose that we are in a Minkowski (flat) space-time with a diagonal (symmetric) metrics $\eta_{\mu\nu} = Diag(-1, 1, 1, 1)$, and $\eta^{\mu\nu} = Diag(-1, 1, 1, 1)$,
The standard Euler-Lagrange equations for a Lagrangian $\mathcal L(A_\nu, \partial_\mu A_\nu)$, is : $\partial_\mu \dfrac{\partial\mathcal{L}}{\partial(\partial_\mu A_\nu)}-\dfrac{\partial\mathcal{L}}{\partial A_\nu}=0$, because the field variables are $A_\mu$, and its first derivatives $\dfrac{\partial A_\nu}{\partial x^\mu} = \partial_\mu A_\nu$ .
The relation between contravariant ($v^\nu$) and covariant coordinates ($v_\mu$),  is simply $v_\mu = \eta_{\mu\nu}v^\nu$, or $v^\nu = \eta^{\nu\mu} v_\mu$. This is the natural relation between "lower" and "upper" indices, and you may generalise it to tensors also, so, for instance your Lagrangian could be written :
$\mathcal{L}=-\frac{1}{4}F^{\mu\nu}F_{\mu\nu}= -\frac{1}{4} \eta^{\mu\alpha}\eta^{\nu\beta} F_{\alpha\beta}F_{\mu\nu}$
Now, you may transform the Euler-Lagrange relations in : $\partial_\mu \dfrac{\partial\mathcal{L}}{\partial(\partial_\mu A^\nu)}-\dfrac{\partial\mathcal{L}}{\partial A^\nu}=0$ or $\partial^\mu \dfrac{\partial\mathcal{L}}{\partial(\partial^\mu A_\nu)}-\dfrac{\partial\mathcal{L}}{\partial A_\nu}=0$ or $\partial^\mu \dfrac{\partial\mathcal{L}}{\partial(\partial^\mu A^\nu)}-\dfrac{\partial\mathcal{L}}{\partial A^\nu}=0$, if you want, but this will bring nothing new or useful to you, so it is better to stay with the "standard" expression of the Euler-Lagrange equations.
The "standard" expression of the Euler-Lagrange equations is more natural too, because $A_\mu$ (as a "connnection") has a "natural" covariant nature (like $p_\mu$), and a coordinate $x^\mu$ has a natural contravariant nature, so a derivative relative to $x^\mu$, that is $\partial_\mu$ has a natural covariant nature. This will become important in curved space-times, where the relation between contravariant and covariant quantities is more complex.
Comment: Thanks! Is there an easy way to see, why the field and the momentum are naturally covariant? Or if you can recommend an introductory text on the topic, I'll gladly read it up myself.
Comment: Think to quantum mechanics. In Heisenberg representation, the momentum operator $P_\mu$ is associated to the differential operator $-i \partial_\mu = -i \frac{\partial}{\partial x^\mu}$, so $P_\mu$ is naturally covariant. Think now to the Schrodinger equation in presence of the electromagnetic field, and you know that you have to do the substitution $P_\mu \to P_\mu + e A_\mu$. It is a sign that $A_\mu$ is naturally covariant. The true reason is that $A_\mu$, is mathematically, a connection.
Comment: If you have a matter field coupled to the electromagnetic field (Quantum electrodynamics), the total Lagrangian would be ${L}=\bar \psi(i\gamma^\mu\nabla_\mu -m)\psi \mathcal-\frac{1}{4}F^{\mu\nu}F_{\mu\nu}$, where $\nabla_\mu = -i\partial_\mu+ eA_\mu$ corresponds to a covariant derivative.
Answer: Varied is the correct word.  Finding the equations of motion, as you have, is done by applying calculus of variations to the action and demanding that the variation be an extremum.  If you were to do precisely that then you would not encounter choices and the confusion you highlight.
However you have applied the concept at the level of the Lagrangian.  That is fine and you will never get anything totally wrong but you may run into little caveats exactly as you did.
Varying the action involves an extra step where you apply integration by parts and that correctly chooses for you the covariant or contravariant derivative based on which type of field you varied with respect to.


How to remove vent assembly from Kenmore 665.16262400 dishwasher

Question: Can anyone tell me how to remove the vent assembly from a Kenmore 665.16262400 dishwasher.  It looks like it should just turn, but I can't get mine to move.
Comment: A photo may help.
Comment: I dug up the user's manual [here](http://www.manual-hub.com/manuals/kenmore-66516262400-pdf-manual.html) ...and the repair manual [here (It's $10 though.)](http://www.allrepairmanuals.com/kenmore-dishwasher.htm?model_number=66516262400)
Answer: Photos would definitely confirm but I believe your Kenmore is manufactured by Whirlpool and has an "open vent" style vent that is not electrically activated. From your description it seems that you already figured out to remove the top 6 T-15 torx screws on the upper inside of the door panel and lower the control panel to reveal the rectangular outer portion of the vent.
If you shine a flashlight into the rectangular "throat" of the outer vent piece you will see how the round inner piece interlocks with it. Your intuition is correct, this two piece assembly simply unlocks and locks together when you rotate the round inner vent piece. If it is stuck you might spray the rim of the inner piece with a penetrating lube and use a hand towel to improve your grip upon it. Wipe off the spray lube afterwards to prevent any damage to the plastic. It is supposed to be tight because both pieces have a rubber seal which prevents water intrusion.


Select Cylinder into Equal Sections?

Question: I'm making a mesh that requires about 6 extrusions from the base model. And Each extrusion needs to be equally spaced apart around the cylinder. Before, I would have to count over and over again the amount of faces in between each selected face "clumps" and it just became really tedious. Is there a way to select (for example) 7 out of every (another example) 33 faces equally spaced apart around a cylinder?
Comment: If the mesh already has those faces cut in then Checker Deselect with propoer setup of Skip and Nth selection will select you according to any pattern. It won't make anything evenly spaced obviously, it will only select existing geometry.
Comment: Possible duplicate: https://blender.stackexchange.com/questions/116534/how-do-you-add-orderly-wrinkles-to-faces/132203#132203
Answer:
You could select all the outside faces, and from the header 'Select'
menu, use 'Checker Deselect', which, starting from your active face,
will skip the deselection of the number of faces set in 'Skip' and
leave a gap of N-1 faces entered in the 'Nth Selection' field, before
skipping again. Sometimes, though, that's surprisingly counterintuitive.
If you've got a lot of rotationally symmetrical work to do, it's worth considering cutting a segment out of your cylinder, and recreating the whole with an Array modifier, set to 'Object Offset', with a rotated Empty at the center of the cylinder as the modifier's target. Then, by working on one segment, you're working on them all.

But for one-off operations like this, it's often quicker to make a jig: a temporary helper object you can delete later.
In the illustration, I've ShiftD duplicated a chunk of faces, E extruded it SZ, scaled it down in Z, and again, ShiftD duplicated it, this time immediately following up with RZ60 rotating the thickened chunk by 60 degrees. Now hitting ShiftR repeatedly will send copies round the cylinder. In this case, they're just markers to save you counting, but they could be snap targets, or view targets.

It may seem a silly amount of work, but once your favorite shortcuts are under your belt, this kind of operation for stashing lengths an angles can become very straightforward, and speed modelling up a lot.
Comment: Thanks Man! This is exactly what I was looking for!

Select Cylinder into Equal Sections?


power4gear for Linux alternative

Question: I have switched to Ubuntu 16.04 and I have installed all drivers. I am using an Asus laptop (n56vz). In order to use its maximum power, I had to install and use Power4gear when I was running Windows.
I would like to know if there is any alternative software which is working like Power4gear but for Linux. Alternatively, is there any way to boost/force my laptop to use all its capabilities?
Right now, when I open 5-6 YouTube videos it starts lagging.
My specs are:

2 GB 650gt mobile
16 GB RAM
core-i7
512 SSD
Comment: Thank you for editing but is there anyone who can help me ? I already checked few apps for Ubuntu which were able to help me for CPU performance control like Jupiter and Cpufreq but both of them are now supported/working anymore...
Answer: CPU control is done via inbuilt intel_pstate thats in the kernel. This effectively controls the CPU power as per need basis. Apart from that TLP as suggested above will help you optimize your system as per the power source. In battery mode it goes on saving mode and turns off turbo on CPU. In power mode all power saving optimizations are turned off. Power4Gear basically would run the CPU at full frequency under Windows. No need for that as Intel's own pstate takes care of that well.
Answer: The linux world offers less 'pseudo optimization tools' from my point of view
What you might consider is - and that doesn't covers everything for sure:
TLP regarding battery usage
TLP brings you the benefits of advanced power management for Linux without the need to understand every technical detail. TLP comes with a default configuration already optimized for battery life, so you may just install and forget it. Nevertheless TLP is highly customizable to fulfill your specific requirements.
You can install TLP via
<code>sudo apt install tlp
</code>
So tlp will most likely not boost your power (however you might define that) - but help optimize battery usage.
GFX Driver regarding graphic power
Ubuntu comes with a GUI which lets you choose 'Additional drivers'. Usually this covers primarily the graphic drivers - check what you are currently using and consider testing others.

It really depends what hardware you are using here - feel free to add this info to your initial post.
Regarding flash
Flash support on Linux isn't perfect - to be honest the best working solution i know for that area is using Google Chrome with its in-build flash version and in addition try to prefer HTML5 on Youtube instead of flash itself to reduce the amount of flash usage in general.

power4gear for Linux alternative


How accurate are constants in cgs units?

Question: I am just curious that if constants in cgs units change the answer of an equation. For example, Coulomb's constant, in SI units it equals to $8.98...\times 10^9 \,\mathrm{N\,m^2\,C^{-2}}$. However in cgs units it equals to 1. I think the difference between an answer calculated with Coulomb's constant in SI units and Coulomb's constant in cgs units would be a lot. I don't know if my logic is right.
Comment: Neither the Newton nor the Coulomb are units in the version of the cgs system where k= 1...
Comment: $k_e$ is absorbed into the units for $q$.
Comment: Coulomb's constant is an exact defined value in both SI and Gaussian-cgs units.
Comment: @StanLiou I mean let's use Coulomb's law. Let's say there are two point charges which is 1 C and 1 cm apart from each other. If we calculate the force in cgs units $k_e\bullet \frac {1 C\times 1 C} {1^2 cm^2} = 1 N$ When we use SI units $k_e\bullet \frac {1 C\times 1 C} {0.01^2 m^2} = 8.98\times 10^{15} N$ There is a huge difference between these answers right? Can you tell me where I am wrong?
Comment: @User58220 Sorry I couldn't find the transformed units for N and C. Could you tell me what the correct ones are?
Answer: I think there's a genuine and interesting physical point to be made here.
Taking a slightly different example, the gravitational acceleration of a massive body on a test particle is $a = GM/r^2$. If you can measure $a$ and $r$ accurately then you can find $GM$ to equal accuracy. But to find $M$ you also need to know $G$, and $G$ is rather difficult to measure. So it's entirely possible in principle to know $GM$ for an astronomical body with better accuracy than $M$, which would make $GM$ a more useful description of the object's mass than $M$, and might make the mass unit in units with $G=1$ more useful than the SI or cgs mass unit. I don't know whether there was any historical era where this was actually the case for any astronomical body, though.
More generally, the measurability/reproducibility of the base quantities of a unit system affects the maximum accuracy of other quantities stated in those units, so some unit systems are actually better than others.
(Edit: according to Wikipedia, "For several objects in the solar system, the value of $\mu$ [= $GM$] is known to greater accuracy than either $G$ or $M$.")
Comment: The [Gaussian gravitational constant](http://en.wikipedia.org/wiki/Gaussian_gravitational_constant) is $$k\equiv\sqrt{G} = 0.01720209895\,\mathrm{AU}^{3/2}\,\mathrm{day}^{-1}\,\mathrm{M}_\odot^{-1/2}$$
which has been introduced with this value in 1809 and has a much higher precision than either $G$ or the solar mass alone. Also, the quantity $\mu = GM$ of a body is usually called the [standard gravitational parameter](http://en.wikipedia.org/wiki/Standard_gravitational_parameter).
Comment: I would think that for *most* major solar system bodies, $GM$ is known far better than $G$ or $M$, and this isn't going to change any time soon. The only non-$GM$ ways of getting mass I can think of are compositional inference and shoving the thing with a known force.
Answer: Take a specific example: two charges of 1 coulomb separated by 1 meter.
In MKSA, (now better known as SI) the force between them is given in Newtons, by:$$F=\frac{k q_1q_2}{r^2}=8.98\times10^9\text{ Newtons}$$since all the variables are 1.
So now you want to do the same problem in cgs-electrostatic units.  $k=1$, $r=100$, and most importantly, $q_1=q_2=2.997925\times 10^9 \text{ stat-coulombs}$, the value of one coulomb in cgs-esu units.
So, the force equation becomes::$$F=\frac{k q_1q_2}{r^2}=\frac{1\times (2.997925\times 10^9)^2}{100^2}=8.98\times10^{14}\text{ dynes}$$which is the same as the previous result in Newtons...
Answer: benrg makes an excellent point that frequently combinations of constants are known better precision than individual constants. We also have the fact that both the cgs and SI units for electromagnetism are, to some extent, historical accidents that predate the modern understanding of the theory. The "natural" units for electromagnetism take advantage of the dimensionless fine-structure constant $\alpha$, defined by
$$
\frac{e^2}{4\pi\epsilon_0} = \alpha\hbar c
$$
Consider that

$c$ and $\epsilon_0$ are defined constants, with zero uncertainty
charge is quantized, in integer multiples of $e$
angular momentum is quantized, in units of $\hbar$

If you're interested in precision, then, instead of cgs or mks units you should use $e\hbar c$ units where many of your quantities of interest are exact integers. Note that the error on $\hbar$ doubles if you insist on using joule-seconds rather than MeV-seconds. If you can choose not to infect your problem with macroscopic units, the uncertainty on the dimensionless $\alpha$ is nearly a hundred times smaller than the uncertainty on the joule-second value for $\hbar$.
However between CGS and MKS there is no difference in precision, nor in the accuracy of the predicted dynamics, since the two systems also use different units for charge and for force.
Answer: The set of constants currently maintained by CODATA goes back as far as 1929 in varying degrees.  These in general have been improving in precision, because this is something of metrological importance.
Measures like $\hbar$ and $e$ are generally derived, there are an assortment of other points that are generally more exact than these.  What the CODATA table reflects, is that the errors are actually pre-linked, so something like $\hbar / m$ is more exact than $\hbar$ or $m$.  It's the other way, really:  $\hbar = m \cdot \hbar/m$.
One can deconstruct the CODATA tables, especially for the electron, into something like C.L.M.T.Q.Þ, where C is a hundred-like number 137.036, and Þ the temperature unit.  Units derived from these base units (rydberg length, electron mass, speed of light, electron charge), are more exact than values like $\hbar$, and even though where the rydberg constant is $4pi$ L, the bohr orbit is L/C, and the classical electron radius is L/C³, is more exact than using $e$ and $m$ to derive these.
The older tables are in CGS, then the current system.  The transition to SI occured after 1947, but the bulk of the conversions in 1960s or so.  So data expressed in SI units are from fresher data, and that is what makes them seem more accurate than the CGS.
CGS and SI use different formulae.  You can construct a common theory by supposing that where $S=U=1$ in SI, and $S=4\pi$, $U=c$ in CGS.  Note that c has dimensions of velocity, and appears when both electric and magnetic quantities appear in the same equation.
$S$ does not appear in the CODATA tables, but it does appear when converting electric flux from cgs to SI, since the correct dimensions here is $QS$.
$U$ makes some appearence, since one sees in older tables $e/c$ as a magnetic quantity, comes as $e/U$.  The equation $\epsilon\mu c^2 U^2 = 1$ is the correct form here.  Since $U=c$ in cgs, it is a constant which has units, dimensions, experimental values and error, so a value known exactly in esu is not exact in emu.
A set of tables from ancient times in CGS units, might be updated using the most exact values of the 2010 CODATA, the values for the missing constants calculated, is as every bit as exact as the current SI data.


camel cxf proxy doesnt work with http endpoint

Question: My requirement is to have a  proxy  web service which will receive the request from clients and then route through camel,enrich it and forward it to real webservice at other clients place ,get response and send it back to the original requestor.
i basically looked at camel-cxf-proxy example (http://camel.apache.org/cxf-proxy-example.html) and camel-cxf-example in camel distribution.Its exactly similar to camel-cxf-proxyand came up with this route
<from uri="cxf:bean:soapMessageEndpoint?dataFormat=MESSAGE" />
<camel:convertBodyTo type="java.lang.String"></camel:convertBodyTo>
<to ref="XService"></to>

where endpoints are
<endpoint id="XService" uri="http://xx.xx.xxx.xx:8080/X_Service" />

<cxf:cxfEndpoint id="soapMessageEndpoint" address="http://localhost:8181/ProviderInformationDirectoryService"  wsdlURL="wsdl/HPD_ProviderInformationDirectory.wsdl" endpointName="s:ProviderInformationDirectory_Port_Soap" serviceName="s:ProviderInformationDirectory_Service" xmlns:s="urn:ihe:iti:hpd:2010"/>

As you can see the second service is http endpoint.And first is the camel-cxf proxy.I just have the wsdl and at this point there is no need for impl.the dataformat is MESSAGE as i need the entire soap envelope to be sent to second web service and there are some useful headers in request from client.But when i run this route with a sample soap envelope it always comes up with 500 response.I am thinking that message sent to real webservice is not what it expects.
I tried trace on camel route but it didnt show much.I was hoping it will show real request to http endpoint.i tried to configure interceptor but that didnt work either.Trace only shows following
 Failed delivery for (MessageId: ID-ALHCAN0437-63941-1354828653539-45-2 on ExchangeId: ID-ALHCAN0437-63941-1354828653539-45-1). Exhausted after delivery attempt: 1 caught: org.apache.camel.component.http.HttpOperationFailedException: HTTP operation failed invoking http://X:8080/X_Service with statusCode: 500

I also tried the following which seems to be working.
<from uri="cxf:bean:soapMessageEndpoint?dataFormat=MESSAGE" />
<camel:convertBodyTo type="java.lang.String"></camel:convertBodyTo>
<to uri="bean:callRemoteWS"></to>

callRemoteWS (callRemoteMethod) gets the soapenvelope as string and makes a HTTPPost request to above endpoint , returns back the response.
public String callRemoteMethod(String request) throws Exception{

            HttpClient client = new HttpClient();

            BufferedReader br = null;

            PostMethod method = new PostMethod("http://x.x.x.x:8080/X_Service");

            RequestEntity entity =new StringRequestEntity(request);

            method.setRequestEntity(entity);

            try{
              int returnCode = client.executeMethod(method);

              if (returnCode != HttpStatus.SC_OK) {
                  System.err.println("Method failed: " + method.getStatusLine());
                  return "Error";
                }

                // Read the response body.
                byte[] responseBody = method.getResponseBody();

                System.out.println(new String(responseBody));

                // Deal with the response.
                // Use caution: ensure correct character encoding and is not binary data
               return new String(responseBody);
            } finally {
              method.releaseConnection();
              if(br != null) try { br.close(); } catch (Exception fe) {}
            }

          }

I am  confused why the simple camel-cxf proxy with http webservice didnt work and the second one works (it should and it does :P).Is the code i have ok.It doesnt seem right to me.I am pretty sure some exchange property is set wrong or content sent to real webservice is wrong.The content got from the proxy is used to make the Httppost call in second route.so the content  from proxy cannot be wrong.when it is got from exchange and send to real webservice something goes wrong. Can anybody throw some light on it.
Answer: I think it was a silly mistake on my part .Soap action header had a different operation and the payload was for a different method.I was invoking the wrong operation with the payload
Comment: don't delete, was useful to me
Comment: Can you please suggest, how you manage to specify SOAP action header as when I am routing to a different endpoint am getting previous operation resulting in same error as you encountered.
Comment: if you find this question not to be useful for others, feel free to delete it :)


Wireless not working in spite of following every locatable work-around

Question: I have a Broadcom 802.11 wireless pci card in my laptop, chipset 4318. I have followed all the instructions to replace the delivered driver with ndiswrapper with the appropriate Windows driver bcmwl5. I've just loaded Ubuntu so the kernel is 3.5.0-17. I had to use ndiswrapper-1.58rc1 to circumvent a problem with modprobe but now when I follow all the steps given for install ndiswrapper I get no errors but still no luck. Driver b43-pci-bridge is listed in /etc/modprobe.d/blacklist.conf but it is still the driver associated with the device according to lshw and I can't find any reference as to where that association is being made. When Ubuntu boots the wireless assistant button on the keyboard is not lit and I can't find any combination of keys or command to get it to light, I assume because the installed driver is wrong. So in short Ubuntu help - Wireless trouble shooting has used up the better part of 3 days but still not produced the desired outcome. Any ideas? I'm sure that if I could find out where that driver is being associated with the device I could make ndiswrapper work instead.
Answer: Ndiswrapper is the least desirable option, in my opinion. Please get a temporary wired ethernet connection, open a terminal and do:
<code>sudo apt-get install linux-firmware-nonfree
sudo modprobe -r b43 && sudo modprobe b43
</code>
Your wireless should now be working.
Comment: you are a genius. It works fine. So why all this fuss on so many sites about ndiswrapper? (rhetorical question of course) If I had found this solution I wouldn't have wasted 3 days
Comment: Many seemingly reliable authorities don't actually understand Broadcom devices as they are driven in Linux in 2013. I barely understand myself because a new chip seems to come out every week, including one new one that has NO way to get working, not even ndiswrapper. I am aware of no Broadcom for which ndiswrapper is the best answer.
Comment: After I installed the latest updates I now have to re-issue sudo modprobe -r b43 && sudo modprobe b43 every time I re-boot. Any ideas what needs to be plugged?
Comment: Please try this terminal sequence: sudo su; echo b43 >> /etc/modules; exit. Does it work now?
Comment: nope, still not working
Comment: Does b43 load on boot without manual intervention now? lsmod Is there some other blacklist? cat /etc/modprobe.d/blacklist.conf or ls /etc/modprobe.d


Does raising the FPS in Fraps cause the video to go faster?

Question: When I change the FPS in fraps to 30, my recording FPS becomes 30, and when I make it 60, my recording FPS is 60 FPS. However, I was wondering; does raising the recording framerate make the video go faster in the end? I mean, will it speed up my video? (as in, 2 times speed)
Comment: It won't make the video any faster, but it *might* make your video go slower, if your PC is not able to keep up with those 60FPS. Fraps recording is extremely ressource hungry, and relies on a reasonably fast storage.
Comment: Do note that your file size get marginally larger when using a higher fps!
Answer: If Fraps is like any sane recording software, no.
FPS stands for frames-per-second, and when initially recording a video it's a measure of how many still images the software/camera will capture per second. You're not condensing the playing time, you're taking more images for each second.
Depending on the frame rate that your playback device (TV, monitor, etc.) runs at, higher FPS may look better - although as I understand FRAPS is specifically designed to record your screen or a game, it can only record the rate that your games are playing at (so it will record in 60fps but as it may be recording something playing at a lower fps, it won't look any better).
It will, however, dramatically increase the size of your recorded files and slow down your load times.
Answer: No, the FPS setting only sets how many frames per second Fraps will capture. The "speed" remains totally unaffected. Note that if you're not getting 60 FPS you may be making your video file larger than necessary (and taxing an already resource-hungry system). I've recorded in both modes, recording FPS never makes the video "faster" and is actually independent of the actual FPS the game is getting (if the game is getting 10 FPS fraps will simply record the same frames 6 times unless you drop frames).
Using 60 FPS to record is generally preferable, but note it will roughly double the file size over 30FPS and many video software suites and websites don't actually support/play back 30 FPS video anyway. I do not believe Youtube generally supports 60 FPS videos for instance.
Answer: I haven't used Fraps but in theory no, because the game would be running on its rate or fps. You're only modifying the rate at which Fraps records the game. So let's take for example Street Fighter 4 which runs at 60fps. Recording at 30fps means you'll miss half of the frames (i.e. looks choppy). Recording at 60fps means in theory you're capturing every single frame the game is running (i.e. smooth). Now recording at 120fps for a 60fps game should not get you any additional benefit.


Does A Good Listing Agent Really Make A Difference?

Question: Considering the agent is providing the same service to all of his/her clients. What other factors do you need to consider in looking for the best listing agent?
Comment: the market makes a huge difference - perhaps mention at least the country here ?
Comment: This other question actually has a great list of questions to ask selling agents. Not a duplicate because that Q is actually about how to choose a buying agent. You haven't noted country, so there might be some other things to consider. https://money.stackexchange.com/questions/16603/what-are-the-most-important-things-to-ask-a-real-estate-agent-before-hiring-them?rq=1
Answer: Yes, a listing agent can make the difference.
I had just experienced this recently in Sydney, Australia. Basically, we had some 2 agents appraise a 4 bedroom house between $2.4M to $2.6M and a 3rd agent appraise it between $2.6M to $2.8M back in July. We had a family member offer $2.5M off-market, but due to them taking more than 3 months to try and get their finances in order, we got another 2 agents to appraise it. They both came back at $2.7M to $2.8M. All 5 agents recommended for us to take it to Auction.
So we decided to negotiate with the 3 agents offering the higher appraisals. We told them what our terms were:

No Auction, listing for sale instead.
Agent to pay for marketing fees ($5k to $7k)
We would only accept $2.9M net (so the agent would have to get over $2.94M to get their full commission or reduce their commission.
If the agent could not achieve $2.9M net for us we had no obligation to sell and we would not be liable for any costs.

Two of the agents were comfortable at paying the marketing fees upfront and getting us $2.8M net and the 3rd agent (he was actually the 2nd agent we negotiated with) agreed to our full terms and to get us $2.9M net, with no costs to us if we didn't sell.
We signed an agreement with him, he listed the property, and in less than 2 weeks of listing the property was sold for $2.945M, with us getting our $2.9M and the agent getting $45k commission.
The thing is that that $2.945M was a record for that area. There had only been one property sold for just over $3M but that one was right on the water, our house was 4 blocks away from the water.


Honeywell thermostat oozing yellow and programing not working

Question: I installed a Honeywell thermostat last year for our boiler and it worked perfectly. This year we were having issues with it not following the program schedule. The thermostat should be sleeping and then will turn on. I took the faceplate off and there is yellow goo inside on the components. Is this just a faulty thermostat or is something else going on? Honeywell has been no help when I have tried to contact them. Thanks!
Comment: Oh, that's just the "honey" that the "Honeywell" thermostat runs on.  But seriously, does it look like the goo came out of the wall or out of the thermostat?
Comment: It came out of the thermostat and I don't see it on the other thermostats. It sounds like this wouldn't be causing the issues that the thermostat is having though.
Answer: That appears to be dielectric grease. It keeps the pins from corroding. I wouldn't have expected to see it on an interior thermostat, but it's not a concern. (It was probably there when you installed the thermostat.)
You can wipe some of it up, but try to leave a thin film on each pin.


Can I set up each space to be a different file location?

Question: I have five spaces that I use regularly. I was wondering if there was any way to link each space to a different location; for example, Space 1 would be Users/Me/Desktop, and the others would be locations of my choice, i.e. folders that I have created. Is this possible?
Comment: A Space/Desktop is a container for *windows*, not files. They're not related to any position in the filesystem, except for the incidental detail that the *desktop* itself happens to expose a filesystem location. I don't believe there's any way to do what you're asking, but what exactly are you trying to achieve?
Answer: It's not possible to achieve multiple desktop locations.
Spaces are not a replacement for desktops. On Stock Mac OS there is only one desktop per user and multiple spaces "above" the desktop.
Additionally it seems there are no tools to achieve this either with Spaces or independently.
Comment: Oh, fine. Sniffle.


The 2011 Nobel Prize in Chemistry

Question: As far as I understand a new pattern of crystal growth has been found experimentally. How does it relate to the known 2D and 3D nucleation and growth of crystals? The dominating theory of crystal growth nowadays is that initiated by Cabrera and Frank. How is the new finding related to what we know so far or is it at odds with what we know and how?
Comment: ""As far as I understand a new pattern of crystal growth has been found experimentally."" No, what he found were new patterns of crystal structure! Laws for seed and growth are the same as for a classic crystals, because that is plain thermdynamics and kinetics.
Answer: The Cabrera-Frank theory is strictly speaking valid for crystals only. Quasicrystals – which were awarded by the Nobel prize – are strictly speaking not crystals. Crystals, by definition, have to be periodic while quasicrystals are not. So details of the theory for crystals of course don't have to hold for quasicrystals. But there are still many similarities in their growth and structure.
Indeed, Shechtman's 1982 discovery falsified some assumptions that people used to believe, e.g. that non-periodic quasicrystals with five-fold symmetries (otherwise behaving just like crystals for which five-fold symmetries are forbidden) were impossible. He was being humiliated by many people before he was admitted to be clearly right.
Comment: thanks for the link where the new definition of a crystal goes as "any solid having an essentially discrete diffraction diagram." I wonder how the discovery at hand relates to superstructures found in amorphous materials and even in water.
Comment: With your definition, amorphous materials are not crystals (these "superstructures" make the diffraction diagram essentially continuous) but quasicrystals are crystals. Concerning the latter point, quasicrystals show that the assumption/proposition that "discrete diffraction diagrams imply periodic arrangement of atoms" was a widely believed myth.
Comment: I am not sure about this. Any structure, if there is such, should give discontinuous diffraction. Otherwise it would go against the essence of waves.
Comment: I think that the adjective "essentially discrete" doesn't mean just "discontinuous". It means a more constraining thing, maybe even a sum of a countable number of delta functions.

The 2011 Nobel Prize in Chemistry


Welcome banner not seen

Question: I am not seeing the welcome banner as show on the design for RPG.se .  Is it my browser (Chrome) or something that is not yet done?
Answer: I can see it just fine.
My guess is that you have only looked at the site while logged in, correct? The welcome banner is only shown to anonymous users. Open RPG.se in an incognito window (Ctrl-Shift-N) and you should see it.
Comment: That is correct.  Thank you for pointing this out.

Welcome banner not seen


How to delete rows from MS Excel which has >65000 rows?

Question: My Excel sheet seems to have 65555 rows - though we're only using the first few hundred. If I delete rows from the bottom it doesn't seem to change anything. How can I resize it back down to what we're using?
Comment: You can't, you can only hide them
Comment: Hide the excess rows.
Comment: Excel supports maximum 1048576 rows, [at least since Excel 2007](https://support.office.com/en-us/article/excel-specifications-and-limits-1672b34d-7043-467e-8e27-269d656771c3#ID0EBABAAA=Office_2007)
Answer: As far as Excel is concerned the unused cells don't exist. It doesn't store them in memory and it doesn't save them in the spreadsheet file. So the number of rows could be infinite without causing Excel any problems. I'd guess the limit of 65536 was just a number sufficiently large that Microsoft thought no-one would ever need that many.
That's why your attempts to delete empty rows have no effect, because those rows don't exist anyway.
If you want to hide all the unused rows for cosmetic purposes the usual strategy is to turn off the gridlines so the unused cells just look blank white. Then you can manually format borders around the cells that you are using.
Answer: This sometimes happens when those cells have formatting but no data

When you save a workbook, Excel stores only the part of each worksheet that contains data or formatting. Empty cells may contain formatting that causes the last cell in a row or column to fall outside of the range of cells that contains data. This causes the file size of the workbook to be larger than necessary and may result in more printed pages when you print the worksheet or workbook.

Locate and reset the last cell on a worksheet

The most common cause of the last cell being set outside the worksheet range that is currently in use is excessive formatting. When you format whole rows and columns, some types of formatting can cause the last cell to be set to a cell far below or to the right of the actual range that is in use.

How to reset the last cell in Excel
If pressing Ctrl+End brings you far beyond your data range then try resetting the last cells. There are 2 ways to do that

Manually clear the formatting

Select all columns to the right of the last column that contains data, or select all rows below the last row that contains data. A quick way to that is press F5 and type F:IV to delete columns F to IV, or 5:65536 to delete rows 5 to 65536
On the Home tab, in the Editing group, click the arrow next to the Clear button then click Clear All.
Save the worksheet and close it

Use VBA

Press Alt+F11 to open VBA
Select Insert > Module, then paste below snippet
Sub ResetLastCell()
    ActiveSheet.UsedRange
End Sub

Press F5 or click Run

For more information

Why does my excel document have 960,000 empty rows?
Ctrl-End doesn't bring me to the last cell
How to reset last cell in Excel?
Comment: The latter VBA option does not seem to do anything in Excel 365.
Answer: Strange thing. None of the above work for my situation. I have sheet with 43498 rows and when in an unfiltered View the last cell is fine and I have no 'extra' rows below, and the vertical scrollbar behaves as expected, i.e. it will take me down to the last row in the table and no further. But when I am in a filtered view (showing 973 rows) then the vertical scrollbar suddenly thinks there are 85559 rows and the scrollbar becomes for all practical purposes, unusable.
This seems like a different issue, or is it?
[EDIT]
Solved, although it remains a strange phenomenon. What worked for me was this answer: https://superuser.com/a/1408570. In short: reset the location of all comments to their natural postition.
Sub ResetComments()
    'Update 20141110
    Dim pComment As Comment
    For Each pComment In Application.ActiveSheet.Comments
        pComment.Shape.Top = pComment.Parent.Top + 5
        pComment.Shape.Left = pComment.Parent.Offset(0, 1).Left + 5
    Next
End Sub

Answer: Actually you can't, but select all rows you want to delete then hide them in view tab and save file. Now you won't see them anymore.
Comment: Considering others have already answered the question with more information. Hiding isn't the same as deleting them.


iOS Multiple Targets For Multiple Customers

Question: Yes i did do some research first... I got a app that need to be released for multiple customers... Currently the API web service URL for them together with other settings are stored in a Constant.h file but off course if we forget to update that file we can release a version to the wrong customer.
I found alot of references to creating multiple targets but only for free ("Lite") or paid apps: http://niharvaidya.blogspot.com/2012/06/how-to-create-multiple-targets-in-xcode.html
What I wanna do: Create multiple targets for each customer, each target share the same functionality, same classes, same research etc... The only thing that is different is the .plist file that is different since it have entries for different customers.
My concerns are:

I can use the Duplicate feature but that also duplicate the .plist file and doesn't create a new one...
If I add new resources to the project I need to check it for all the targets (customers), what if later on i add a new customer target... Do I need to go back to ALL those resources and re-add them to the new targets?

Thanks
Answer: basically I'm facing the same problem...
but take a look at this guide, using Xcode 5:
iOS Mobile Development: Using Xcode Targets to Reuse the Code
although it doesn't answer the 2 issues you mentioned, maybe you'll find it helpful using variables in the .plist files, as it's done there... for example:
<code>${APP_BUNDLE_ID}
${YOUR_USER_SETTING}
</code>


For the purposes of building credit, does dividing up a loan help?

Question: I want to enhance my credit with share secured loans (I'm a member of a credit union).  All else being equal, will paying off 5 $200 loans give my credit score more of a boost than one $1000 loan?
Answer: Having worked at a credit union, I have some input:
The things that have the greatest impact on your credit score are:
What is your oldest line of credit, and how old is it?
The older a line of credit (think your first Credit Card still open), the more lift to your score.
What is your total debt to available credit when the report is pulled?
The more of your 'credit' that you have utilized, and the less 'credit' you have left, the lower your score.
Are you "paying as agreed" on all of your lines?
Making payments past due definitely hurts your score, as it indicates a difficulty/inability to replay, meaning you're more risky to an institution.
How many credit "inquiries" have you had recently?
Have you been looking for credit at multiple locations and frequently? This can be a red flag to a lender.
How many new accounts have you open, and how many do you currently have open?
Too many new, and too many accounts in general may indicate that you rely heavily on credit v. cash/assets. This also indicates risk.
I'd advise you to open just ONE loan, and pay it on the schedule. Otherwise, you'd be opening several new accounts simultaneously, which is highly unusual for these purposes, especially if they are all of the same type.
It will take time, but your credit will build. Right now, if you have new/no credit, they have nothing to base their decision on. Once they can see your history of repayment, you look like more of a 'safe decision' in terms of lending. That's really what credit score is all about, IMO.
Secondly, I'd highly advise a line of credit v. a personal/installment loan. A line of credit may remain open indefinitely, and you can have the credit line increased. Both of those things are HUGELY positive on your credit score. It shows you can utilize credit responsibly and repay what you take as a loan.
Also, keep in mind that there are 3 credit reporting agencies, all with their own proprietary formulas and methods, and I believe at last check, only 2 have published their formula's publicly.
Comment: If you happen to know, would you mind defining how long "recently" is for recent inquiries, and also "new" for new accounts?
Comment: I would try to not open more than 1 account every 6mo, and try to have fewer than 10 lines of credit, loans, etc. at any one time. Also, anything more than 1-2 inquiries every 4-5 months will definitely have a negative affect on your credit score. Of course this is generalizing, and assuming typical size loans.


Persisting Google Drive Session Data across University networks

Question: This seems to be an issue I've been seeing multiple people having issues with and has yet to be solved effectively. How can one maintain Google Drive at an enterprise level?
I'm working as a student programmer for my University and they just switched to Google Apps for Education and want to use Google Drive to allow students access to campus computer data anywhere.
Our campus system is called Labnet and it boots a fresh copy of Windows 7 using iSCSI and a logical volume manager. Every time students boot up a box, its the exact same fresh new PC smell. Because of this, the oAuth key google drive adds to the registry is blown away at reboot as is the drive folder and app data folder, all which like being on the C drive.
We built a wrapper for first time users to set up Drive on campus which redirects the default install location to the network drive and copies the app Data folder containing the sync_config.db and snapshot.db files to a network backup and exports the drive key to the network drive. At login, we have a script check for the backups, restore them all to C:\users\admin\appdata\local\drive, and import the oAuth token into the registry.
In theory, it works fine. In practice, its so so. The setup works fine in one lab where all the machines run the exact same hardware and are booting the same image file. When we try the importing the keys and appdata to a lab running slightly different hardware and software, we get Error -2146893813 CryptUnprotectData, 'Key not valid for use in specified state'. or invalid data.
I didn't think the oAuth was in anyway tied to the hardware or software of the machine, but it seems like it is.
Does anyone know of a way to persist this data in such a fashion that would allow users to access data without having to constantly setup drive at login?
I'll attach the full code here. It's a more than standard code block, So here's a link.
GoogleDriveLabnetConfig.py is the custom wrapper that changes the default Drive location to the H: drive.
https://www.dropbox.com/s/fb27936jmm87w0l/GoogleDriveLabnetConfig.py
MUNGoogleDriveDaemon.py is a wrapper that copies the user's Appdata back and forth between C: and H: and actually launches Google Drive. We don't allow users to launch Google Drive independantly of this daemon because the snapshots won't be backed up.
https://www.dropbox.com/s/z32t3bjluwl0wf5/MUNGoogleDriveDaemon.py
If anyone can help solve this, feel free to reuse the code in your own setups.
Edit: It might be possible to check the hardware and software of each computer at start-up and import a key generated for a specific hardware/software pairing, but that would result in users having to renter credentials every time they change labs and if we change the image, again in old labs. Not a very elegant solution.
Answer: A long shot, but try checking the system time on the machines. Oauth requires that all clients and servers have synchronised time.


How can i disconnect part of mesh, reconnect it to another part and make it a part of different UV island?

Question: I was modifying a boot model consisting of several meshes and ran into a big problem. I have two main mesh parts: the sock (top image on the left) and the boot (top image on the right). I need to disconnect a part of sock (bottom image on the left) and reconnect it to the boot mesh. I tried doing this by hitting the Y short key but this creates additional vertices which messes with the export script. So i need to disconnect and reconnect without changing the total vertex/edge/face count.. I also need the repositioned bit to become a part of a different UV island (bottom image on the right - i sort of drag-and-point where i want the piece to move to). Again, i can't unwrap because blender creates a totally different layout.. I'm almost positive that it's just impossible to do all that but maybe i'm missing something. I've spent 6 hours modifying the model before i realized there was a problem...
Answer: This is old question but I'd figure I'll post possible answer anyways because someone else might google this.
I'd just pin (select these verts and press p) the vertices in uv editor that need to stay put. Leave all seams unpinned. Then just press u and do basic uvunwrap the whole mesh. Only those vertices that you wanted to move should move. If you get weird result then you probably have a missing seam, wrong vertice pinned, hidden geometry in edit mode or something else. After the uvunwrap press alt-p in uv editor to get rid of the pin tool.


WD Caviar Green freezes server before boot

Question: I have a server with an Asus P8Z68-V motherboard, running Ubuntu Server. The system boots fine with the boot disk on SATA-0, and a 2TB Hitachi HDD on SATA-1. However, when I replace the 2TB Hitachi with a 3TB WD Caviar Green hard drive, the system freezes during boot at the splash screen (ASUS motherboard, press DEL to enter UEFI BIOS setting, etc). The SATA controller is set to IDE mode. The disk does not appear if it is connected after the system is booted. I have updated to the latest BIOS image, an 05/2012 release.
Comment: Can you try to change your controller from IDE to ACHI? I've seen this a few years back and there was an option for delaying the boot while the hard drives spin up. It wasn't a huge delay, just a couple of seconds. If you had your Green as the primary drive, you would probably get a OS Not Found error.
Comment: Sorry I should have said that, the freeze happens in both IDE and AHCI modes. Also, since I posted the question, I tried the following: Unplug the Caviar. Power on the system, and stop GRUB from auto-selecting the OS. Plug in the Caviar, wait for it to spin up, then allow GRUB to continue with lé boot. This had no effect, the drive never showed up in /dev.
Also, it probably doesnt matter, but the drive is exFAT formatted. I have the Ubuntu exFAT driver installed, but the machine isn't even getting to Ubuntu, so...
Answer: well i would first try to change the hdd mode in bios if its a sata drive you want the controller to read sata not ide. so switch the mode. usually press enter on the mode and - or + to change then press F10 then enter to save. reboot see if it shows up in the post screen. also some asus boards, IE: mine you also have to enable sata mode in bios settings.on the selected sata ports:
for example: mine is under main tab / IDE Configuration /
SATA 1:      [Disable] [Enable]
SATA 2:      [Disable] [Enable]
nVidia RAID Function:          [Disable] [Enable]
SATA 1 Controller:             [Disable] [Enable]
SATA 2 Controller:            [Disable] [Enable]
{Unless you want to use raid}.
After you make these changes F10 / enter for YES to save changes.
Hope this Helps, Chem


Proving that number is least upper bound

Question: I am to find supremum and infimum of given set, and prove they are in fact supremum and infimum.
$$A=\lbrace x\in \Bbb{R}:x^2-5|x|+4\lt0\rbrace $$
$$\sup A = 4, \inf A = -4$$
I tried to prove it in the following way, let $\varepsilon\gt0, a\in A$,
then if $a\gt 4-\varepsilon$, $4-\varepsilon$ is no upper bound, so I can set $a$ to be equal to $4-\frac{\varepsilon}{2}$ and therefore $4-\varepsilon$ is not upper bound what proves that 4 is least upper bound. Proof for greatest lower bound is similar.
My question is, is my proof correct?
Comment: How do you know $\exists a \in A$ such that $a > 4 - \epsilon?$
Answer: Equivalently, $A = \{x \in \mathbf {R} | 1 < |x| < 4 \}$. This proves that $$\inf A = -4 \qquad \sup A = 4.$$


Chlorine Fluoride, why not Fluorine Chloride

Question: Why is Chlorine Fluoride called "Chlorine Fluoride" rather than "Fluorine Chloride"? As I was taught in school that normally that when nonmetal combine with nonmetal then we write the compound with lower atomic number first.
Comment: Think about electronegativities.
Comment: Anionic part is written in the suffix.
Answer: Basically, with interhalogen compounds (and possibly most of binary inorganic compounds) are named like "element" "element'ide'", where no suffix is used for the electropositive part (eg: sodium, oxygen, nitrogen), and a suffix "ide" is used for the electronegative part (eg: chloride, oxide, nitride, phosphide, carbide).
Regarding $\ce{ClF}$, fluorine is clearly the electronegative atom here. Thus the name would be Chlorine fluoride.
Another example of this is from my personal favorite compound, $\ce{O2F2}$
Here, we have subscripts to indicate the number of atoms. In such cases, we add prefixes "di" or "tri" or "tetra" to the name.
$\ce{O2F2}$ would be correctly called as Dioxygen difluoride.
Comment: +1 for FOOF. Have a relevant blog link: http://blogs.sciencemag.org/pipeline/archives/2010/02/23/things_i_wont_work_with_dioxygen_difluoride
Comment: FOOF is tremendously amazing and terrifying
Comment: @DoktorJ I read that article too. FOOF is a pretty interesting compound indeed.


WebService IOS design optimization

Question: Im using a web service to populate a tableview, but the data in my web database changes very rarely, and i don't need to always download the same data.
I need to storage the data in the device, and verify if the data on the device is different than the one on the web.
What is the best practice to do that? Parse a JSON object, containing the last version and comparing to the local version and then parsing the data if its needed ?
Is there a way to automate the last version?
Answer: I personally used local storage for the same situation on iOS and it worked great.
You just need to provide an URL which responds with the last version of the data (maybe a date) and then locally in JavaScript you first check if version online is newer than your local stored one, if it is you redownload data and place it into localstorage, otherwise you just keep old data (and don't download anything at all).
Of course everything must be done through Ajax.
Answer: If you have control over the web APIs then have a separate api that returns a timestamp for the last web data change and check this. If the date is not newer than the date of last download use the local data. imho.

WebService IOS design optimization


Will Ubuntu 16.04 LTS have a 4.5.2 kernel update?

Question: Will Ubuntu 16.04 LTS have an update for kernel version 4.5.2? I have an AMD GPU installed, and I heard this would fix AMD driver problems.
Answer: Ubuntu 16.04 will never have a 4.5.2 kernel update.
Ubuntu does not update with mainline kernel versions.
Canonical Kernel Team backports bug fixes and some support of new hardware from upstream kernels to Ubuntu kernels.
Important fixes get into Ubuntu kernels 4.4.0-xx from 4.4, 4.5, etc mainline kernels.
You can see the source of Ubuntu 16.04 kernel HERE.
It is possible that the fix you need has been already backported.
Answer: No, Ubuntu 16.04 will not have version 4.5.2 of the kernel. As you can see from a picture (taken from 16.04.x Ubuntu Kernel Support) of the kernel timeline for Ubuntu 16.04 below, the next version of the kernel will be a fork of version 4.8 of the mainline Linux kernel.
Comment: This is not 100% correct. It will not be `4.8.x`. It will be a fork of 4.8 ;-)
Comment: @Pilot6 `x` was meant to denote the versioning on Ubuntu's side, but you are right ;). Let me fix it.
Comment: As you're a reputation 21 user: if this answers your question, don't forget to click the grey ☑ under the "0" at the left of this text to [accept it](/help/someone-answers), which means "yes, this answer is valid"!


Replacing switch with dimmer switch - 2 red wires and 1 yellow wire

Question: I'm trying to replace an existing single pole switch with a dimmer switch for a 4 bulb vanity light.  Trying to replace with a Lutron DVCL-153PR-WH switch.  Upon opening the box I am faced with 2 red wires and a yellow wire.  No ground and the beige wire is capped off in the box.  New switch has a red, black, red/white striped, and green ground wire coming off it.
Existing switch appears to be single pole as it doesn't control anything else except vanity light.
The presence of the 2 red and a yellow is throwing me off.  Looking for some help.  I have included photos:
Comment: Good to see you replaced that switch because it was not wired very well. The wire should have been looped around the screw. Looks like the switch may have a clamp style screw on there which is why there's no loop. I point this out as you may have other switches/outlets that are a potential fire hazard.
Comment: Beige is almost certainly aged white (and neutral, for sure, in conduit, barring code violations.)
Comment: To reinforce what @PlatinumGoose said, please see [this pic](https://imgur.com/a/K0cyFGB). As that wire was tightened down, the screw was forcing it out of the clamping area (see red arrow). The wire should have been inserted into the slot in the blue plastic (green rectangle) in the direction of the green arrow, and gone _under_ the brass plate. Then when the screw tightened, the wire is _clamped_ under the brass plate. (This would apply to _all_ the wires on this switch. There's even a **big yellow sticker** that says how to do it...
Comment: Fortunately several other switches have been replaced with home improvements over time but this is something I will keep in the back of my mind.  Installing this dimmer switch really exposed me to some electrical knowledge.  Thanks!
Comment: While I'm at it... I just noticed that in the next to last pic, there is some [copper showing](https://imgur.com/a/3zaXjKe) in the neutral wire bundle. That's a no-no. Either that one wire wasn't pushed up far enough into the nut (and electrical contact it minimal at best) or it was stripped too far and needs to be trimmed to match the length of the other wires.
Answer: Whites are neutral. If your new switch needs neutral, add a short white wire (pigtail) and connect it to the others.
Metal conduit + metal boxes = strange wire colors and grounded automatically. All switches, better quality receptacles ground automatically with metal boxes.
In the old switch, one red is incoming hot, one is outgoing hot, yellow is switched hot.

Connect the two reds to black of the new switch with a wire nut.
Connect yellow to red of the new switch.
Cap the striped red.
Connect the green ground wire from the new switch to a grounding screw in the metal box. If the green wire is removable (not clear with a quick look at the instructions) then you can remove it as the switch will ground to the metal box through the yoke.
Comment: Perfect!  just wired the dimmer switch and it works exactly as desired.  Thanks for the help and explanation.  It made a ton of sense!
Comment: @Bueller, note that _in **this** case_ red is incoming/outgoing hot and yellow is switched hot. The colors could be different in other boxes in your house, though one would _hope_ the electrician was consistent. There is no _requirement_ that he be consistent (other than the general "workman like manner" for doing work). If he ran out of yellow, he may have used any other color (except white, grey & green) as a switched hot...
Comment: @FreeMan thanks for calling that out. I've already thought the same thing.  I just recently replaced 2 light fixtures in the hallways and they were wired with he appropriate color wires.  My initial thought was the electrician ran out of a color and just kept going.  House is 40 years old, so who knows going back that far.


Understanding a negative sentence

Question: "I don't like anything that's not expensive"
Can anyone explain what this means? Do they only like expensive things or they don't?
Comment: I don't think the sentence of interest contains a double negative.  Yes, it contains two negatives but they apply to different parts of the sentence.
Comment: Double negatives are culturally relative, so any answer may be right or wrong depending on culture. In some (English speaking) cultures, a double negative is an emphatic negative ("I'm sure I don't know nothing at all") but in most (English speaking) cultures, the negatives cancel out.
Comment: Remove the negatives from the sentence and the gist is similar - *I like anything that's expensive*.  Note, however, that the meaning is not the same.
Answer: Yes, the speaker only likes things which are expensive.  The sentence is syntactically acceptable and entirely clear.  Perhaps, to make it clearer to yourself you could replace not expensive with cheap and see how that works.
Comment: As I said on a earlier deleted answer, the sentence only states that they don't like cheap things. Without further information you cannot be sure that "the speaker only likes things which are expensive" - they might dislike expensive things as well.
Comment: @KillingTime That is strictly true, but nit-picky. The intent of a typical speaker saying this would be to discriminate between what they like and what they don't like. If they didn't like anything, they'd say that instead.
Comment: @DMac They could dislike cheap things and be *ambivalent* about expensive things. Not disliking something doesn't necessarily mean liking it. And I think it's essential to be *nit-picky* in this case, since the question is asking for us to analyze it. The intent behind this statement, to me, has nothing to do with discriminating between two things. It's just a simple statement of dislike, Nothing is being said about anything else.

Understanding a negative sentence


Contact deleted from phone but still visible in WhatsApp

Question: First i deleted chat from WhatsApp, then i deleted contact from my phone. Then i refreshed WhatsApp 2-3 times but when i type name in search bar, that contact is visible in WhatsApp without any previous chats.
Answer: Whatsapp (like some other apps) makes clones of contacts.  So, for a particular contact, there is a Phone/Sim entry and there is a Whatsapp entry.
To delete from Whatsapp.

Search for Contact on Whatsapp
Press on 3 dots
Select View Contact

Then

You can block the Contact

Or

Press on 3 dots
Select View in Address Book
Select More
Select Delete

If you have a whole lot to do then a Contact Manager App can make it easy.  I use Contacts Optimizer (I am not associated with it)

To prove it, here is a screenshot from Contacts Optimizer.  This is page 2 of the accounts, I am showing this page to show Whatsapp.


What connection do Mars rovers use to send data to Earth?

Question: How do Mars rovers send data back to Earth? Do they have some kind of built in WI-FI routers or is there any other connection?
Comment: Please ask only one question per question. If you have two questions, ask two questions. It would also help if you could explain what research you have done, what answers you found, and why those answers were unsatisfactory to you. That way, you avoid people wasting their time telling you stuff that you already know.
Comment: "How do Mars rovers send data back to Earth?" can be answered by looking through this site. Even requiring three tags gets enough answers to answer this. [`communication` + `mars` + `rovers`](https://space.stackexchange.com/questions/tagged/communication+mars+rovers)
Comment: Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
Comment: World's longest Ethernet cable.
Answer: Generally what happens is that radio signals are sent from the Martian surface to a spacecraft orbiting Mars, which then sends the data to Earth.
As an example, the current NASA missions on the Martian surface (Perseverance, Curiosity, and InSight) send data via radio signals to the Mars Relay Network, which consists of various NASA and ESA Martian orbiters. This network then relays the radio signals to Earth that is picked up by a network of three radio antenna facilities known as the NASA Deep Space Network.
Update: Directly sending a radio signal to Earth from a Mars rover is also possible through a High Gain Antenna, albeit at a lower data rate (ex. Curiosity and Perseverance).