Are umbral moonshine and umbral calculus connected?

Question: In a 2013 article, Cheng, Duncan and Harvey introduce the concept of umbral moonshine as a generalization of monstrous moonshine. The terminology they use, starting with the title, is common in umbral calculus of Rota, Roman and others. The articles by Cheng et al. lack any clarification on the homonymy, or links to works on umbral calculus, which suggests that the similarity in terminology may be coincidental. At the other hand, q-calculus emerges in texts on umbral calculus here and there, and a 2009 PhD thesis by Robinson loosely connects umbral calculus to the theory of vertex operator algebras, so it is not impossible to imagine that a common ground for umbral moonshine and umbral calculus could exist. Since the article treats pretty complex material I am not familiar with, I wasn't able to immediately understand from the text, if any analogy to the classical umbral calculus is present, so, before dedicating a substantial amount of time to further attempts, I would like to ask if anyone else already knows the answer.
Answer: We used the word "umbral" because umbral moonshine involves mock modular forms whose lack of modularity is characterized by another function known as the shadow of the mock modular form. Umbra is the Latin word for shadow. We did not mean to imply any connection to umbral calculus.
Answer: Despite the authors not intending to imply a link to umbral calculus per se, there is indeed a connection of the umbral calculus / Sheffer polynomial operator calculus to monstrous moonshine as I noted in my MO-Q "Combinatorics for the action of Virasoro / Kac–Schwarz operators: partition polynomials of free probability theory":
The association with monstrous moonshine is via the noncrossing partition polynomials of OEIS A134264, which are related to the compositional inversion (CI, or series reversion) of Laurent series with the free cumulant partition polynomials of free probablility theory as numerators and also the CI of o.g.f.s / formal power series via their shifted reciprocals.
The (formal) Laurent series for the Riemann mapping
$$\mathit{LC}(z) =  \frac{1}{z} + c_1+c_2z+c_3z^2+\cdots$$
$$= \frac{1}{z} + m_1+(m_2-m_1^2)z +(m_3 -3m_2m_1+2m_1^3)z^2 + \dotsb$$
has the CI
$$\begin{align*}
\mathit{LC}^{(-1)}(z)={} & \frac{1}{z} +   \; \frac{m_1}{z^2} +   \; \frac{m_2}{z^3} +\;\frac{m_3}{z^4}+\dotsb \\
={} & \frac{1}{z} +   \; \frac{c_1}{z^2} +   \; \frac{c_2 + c_1^2}{z^3} +\;\frac{c_3 + 3\; c_2c_1 + c_1^3}{z^4}+\dotsb.
\end{align*}.$$
$LC(z)$ has the form of the elliptic modular invariant of eqn. 1.1 of the pdf by Harvey et al. and the q-expansion of the modular invariant j-function of eqn. 10 on p. 6 of "Modular Matrix Models" by
Yang-Hui He and Vishnu Jejjala.
The multivariate polynomials in the numerators of $\mathit{LC}^{(-1)}(z)$ are the partition polynomials of A134264, which I usually call the noncrosssing partition polynomials or the refined Narayana partition polynomials or the refined h-vectors of the associahedra but also the free cumulant partition polynomials or Voiculescu polynomials of free probability / random matrix theory. See, e.g., eqns. 35 an 36 on p. 11 of H&J. (See also "Three lectures on free probability" by Novak and LaCroix and "A Simple Introduction to Free Probability Theory and Its Application to Random Matrices" by Xia.)
Of the various sets of CI partition polynomials I've come across, this is the only one that is an Appell Sheffer polynomial sequence in a distinguished indeterminate. Taking the derivative w.r.t. $c_1$ gives a simple spot check of this assertion, illustrating the iconic property of Appell sequences, the lowering operation
$$D_{c_1} P_n(c_1,c_2,...,c_n) = n \cdot P_{n-1}(c_1,c_2,...,c_{n-1}),$$
e.g.
$D_{c_1}P_3(c_1,c_2,c_3) = D_{c_1}(c_3 + 3\; c_2c_1 + c_1^3) = 3(c_2+c_1^2) = 3P_2(c_1,c_2)$.
So, $D_{c_1}$ is a lowering operator. The umbral calculus formalism of Appell sequences then implies
$$(P.(c_1,c_2,...) + \alpha)^n = \sum_{k=0}^n \binom{n}{k}P_k(c_1,..,c_k) \alpha^{n-k}= P_n(c_1+\alpha, c_2,...)$$
as long as $\alpha$ commutes with all the indeterminates in multiplication, analogous to the Hermite and Bernoulli polynomials. An Appell raising op can be formed as well and this gives rise to an associated differential evolution equation for the e.g.f. of the sequence--in umbral notation, $e^{tP.(c_1,c_2,...)} = e^{tP.(0,c_2,...)}e^{tc_1}$--and recursion relations.
The numerator polynomials of $\mathit{LC}(z)$ are the free moment partition polynomials of A350499. They do not form an Appell sequence in a distinguished indeterminate.
On a more basic level, the SL_2 group is related to the ops $D_z, zD_z,$ and $z^2D_z$, which can be related via normal ordering to the Pascal, Bell, and factorial-normalized Laguerre polynomials of order -1, or the Lah polynomials, all binomial Sheffer sequences with associated binomial convolution properties and raising and lowering ops easily described with umbral calculus in terms of umbral compositional inverses (or pairs of invertible triangular matrices). See, e.g., this MO-A, this MSE_A I, and this MSE-A II. The associated Laguerre polynomial diff ops, which can be derived from the Laguerre diff ops of order -1 by conjugation, are related to automorphic/modular forms and to general Sheffer polynomial sequences and, therefore, to umbral calculus as well.
Naturally, these machinations are also related to the Dedekind eta function. See my pdf in my post "Infinigens, the Pascal Triangle, and the Witt and Virasoro Algebras" and search on Dedekind.
Comment: Umbral moonshine is gently introduced in a later portion of the Youtube vid "Mock Modular Forms are Everywhere" by Miranda Cheng (https://youtu.be/dOY_MzmS0Zk?si=FetB4kc3EhKHysAi)  and in the expository vid "Rogers-Ramnujan and Umbral Moonshine" by Ono (https://youtu.be/NNa_njwB5l8?si=u8ig2F3ybXvKS2hU).
Comment: For connections among theta series and associated Laguerre polynomials and Hermite polynomials, see "Square roots of central values of Hecke L-series" by Villegas and Zagier (https://people.mpim-bonn.mpg.de/zagier/files/mpim/92-68/fulltext.pdf).
Comment: For connections of generalized umbral calculus via Ramanajun's master formula to theta functions, see links in the section "F) Mellin transform of the Gaussian, Mellin transform interpolation of the coefficients of the Gaussian" of my answer to the MO-Q https://mathoverflow.net/questions/40268/why-is-the-gaussian-so-pervasive-in-mathematics/383402#383402.


Archiving tables with Access frontend and linked SQL Server

Question: I'm working on a project where the user has an Access 2013 MDB database with forms, reports, and queries. We're converting it to use linked tables to SQL Server 2008 R2. All the linked tables seem to be working well.
The user needs the ability to archive some tables annually, and be able to read the data. These are not particularly large tables (the whole MDB is 27MB). Currently, the users make a copy of the MDB file every year and use that as their archive. They need the old data for comparison with the current information.
How do you archive linked tables via Access? It's not feasible to copy the entire SQL Server schema every year. Maybe if we just back up the tables and link again? What's the recommended approach to this? Thanks.
Answer: Try creating a separate historical file with nothing but the archived data table. In the example below you can see there is a linked table. I imagine your linked SQL table appears similar but pictured as a blue globe and is connected. Right click the linked table and select Convert to Local Table. This will sever the link and create a local table. Name it <code>[tblYourTable_2016]</code> for example.
OR
You could create a Make Table Query and recreate it that way as well. Either way I would keep the history files in a separate and secure file.
[]


How do you configure RadRails to use Rails installed through RVM?

Question: How do I properly setup Aptana RadRails if I've installed Rails through RVM?
I followed the install on http://railstutorial.org/ but my script paths don't work: e.g.:

'rails' path: /home/marius/.rvm/gems/ruby-1.8.7-p302@rails3gemset/bin/rails
Detected path: Not Detected
Comment: Got any luck..? I am also having the same problem...
Answer: try to run this in the command line. It will show you real path to the available rail script for current environment.
$ which rails
Answer: After installing ruby through rvm, I was able to get eclipse to use that install by:
In Eclipse, go to Window -> Preferences.
In the Ruby/Interpreters tab click "Search"

For me this found all of the ruby installs from rvm, and it added them to the interpreters list. I edited the "Name" field to include the version number for convenience.
Answer: In Aptana Studio 3 (build: 18.104.22.168201201658) there is no Window -> preferences. If you have a .rvmrc in your project work directory, stating for instance:
rvm use ruby-1.9.3-p0@mygemset

... then Aptana should pick up the correct environment; in this case using ruby-1.9.3-p0 with gemset mygemset. Don't forget to run build install or build update (when you updated your Gemfile) from your project working directory path.
I must add that Aptana Studio 3 seems a bit buggy when it comes to picking up the correct environment, especially when trying to use ruby-debug-ide19.
Answer: Did you try with just /home/marius/.rvm/gems/ruby-1.8.7-p302/bin/rails ?
Answer: You have to run eclipse/aptana from a terminal session.
Answer: Without RVM  :
Please type command whereis ruby in console.
you will get the path like /usr/bin/ruby or /usr/local/bin/ruby to check which is correct  interpreter path /usr/bin/ruby -v if you get version. that is your interpreter.
With RVM  :
Please type command: rvm info
binaries:
    ruby: "/home/<USERNAME>/.rvm/rubies/ruby-2.0.0-p247/bin/ruby"

copy this path and paste wherever you need enter you interpreter path.
It worked for me. and I hope it will help others as well.
Cheers!


Google Webmaster Tools show only common words in the keywords list

Question: I have a greek site with greek domain (gr) and even so, the keyword list of google shows in the first places the greek equivalent words of the common words like "in", "a", "and",etc.
All them would be greek's Stop Words
Thanks for any help
Comment: Are you talking about "Optimization" -> "Content Keywords" or "Traffic" -> "Search Queries"?
Comment: Google Webmaster Tools/optimization/content keywords
Answer: My Greek site has similar data.  My top keywords under "Optimization" -> "Content Keywords" are το, για, and της, the Greek words for it, for, and of.
I've spot checked my site in several other languages.  Spanish, Italian, and Arabic don't appear to exhibit this behavior.
This appears to be a bug in Google Webmaster Tools.  It appears that for Greek sites, they are not properly identifying important words compared to common words.  Since this issue affects multiple Greek sites, I wouldn't worry to much about it.  Google should be able to fix it at some point.  In Webmaster Tools you could tell Google about this problem using "Help" -> "Send Feedback".
Comment: Thanks Stephen! That not solve the problem but your answer save a lot of time of research. Thanks a lot


Connected, maximal compact, but not $T_2$

Question: Is there a connected topological space that is maximal compact, but not $T_2$? (A space $(X,\tau)$ is said to be maximal compact if for any topology $\tau'$ on $X$ with $\tau'\supseteq \tau$ and $\tau'\neq \tau$ we have that $(X,\tau')$ is not compact.)
Answer: Let $X$ be any compactly generated connected Hausdorff space that is not locally compact and let $Y=X\cup\{\infty\}$ be its one-point compactification.  Then $Y$ is compact, connected, and not Hausdorff.  To show $Y$ is maximal compact, we must show that every compact subset $K\subseteq Y$ is closed in $Y$.  If $K\subseteq X$, then $K$ is closed in $Y$ by definition.  If $\infty\in K$, it suffices to show that $K\cap X$ is closed in $X$.  Since $X$ is compactly generated, it suffices to show that $K\cap A$ is closed for every compact subset $A\subset X$.  But any such $A$ is closed in $Y$, so $K\cap A$ is closed in $K$ and hence compact.  Since $X$ is Hausdorff, this implies $K\cap A$ is closed in $X$.
Answer: Yes. Let Y be any compactly generated connected Hausdorff space such that Y fails to be locally compact. Let X be the one point compactification. X is maximal compact (since compact subsets of X are closed), but X is not Hausdorff.
See for example, Example 99 from Counterexamples in Topology by Steen and Seebach.
Comment: The one-point compactification will not be maximal compact unless $Y$ is compactly generated.  Indeed, if $A\subset Y$ has closed intersection with every compact set but is not closed, then $A\cap \{\infty\}$ is compact but not closed in the one-point compactification.


How do Spectre patches work?

Question: How could Intel/Microsoft provide software patches to Spectre, which exploits the speculative execution nature of superscalar processors, which is a hardware feature that cannot be modified or disabled (at least not without massive loss of IPC gains stemming from speculative execution)? How do these "patches" actually work?
Comment: Why do you think it's a hardware feature, or why do you think the hardware is fixed? It may be a software layer such as microcode that actually implements x86 architecture on a RISC type CPU, or the hardware is implemented as a programmable logic like FPGA and microcode patches alter how the programmable logic works or just tells the hardware to disable that feature.
Answer: There are various techniques to mitigate Spectre-style vulnerabilities in software without patching microcode or changing hardware, but they do incur some performance cost. I'm not familiar with how Microsoft implement these mitigations, but the Linux documentation is comprehensive.

For the Spectre variant 1, vulnerable kernel code (as determined by code audit or scanning tools) is annotated on a case by case basis to use nospec accessor macros for bounds clipping [2] to avoid any usable disclosure gadgets.

For Spectre variant 2 mitigation, the compiler turns indirect calls or jumps in the kernel into equivalent return trampolines (retpolines) [3] [9] to go to the target addresses. Speculative execution paths under retpolines are trapped in an infinite loop to prevent any speculative execution jumping to a gadget.

The references here describing the mitigation techniques aren't inherently ways to prevent Spectre-style information leakage, but they are practical solutions to the problem that come from the way the affected processors are implemented.
Comment: Also important to note that Intel's and AMD's microcode updates don't mitigate Spectre at all *on their own*.  They provide hooks that software (such as a kernel) can use at certain points to make later branches not depend on the history of earlier branches, and stuff like that.  (And for AMD, a way to set LFENCE to be a barrier to (speculative) execution; previously AMD's LFENCE was a no-op (could run 4/clock) since they didn't previously document an execution-barrier behaviour for it the way Intel did.  Which is what made LFENCE useful for ordering RDTSC wrt. code being timed.)
Answer: In some sense you are right. This is a hardware issue that can only be solved in hardware.
In fact, I would even go one step further: this is a mindset issue in the entire industry. The entire industry as a whole has made the mistake of emphasizing performance over security and of not properly considering the insanely complex interactions caused by piling complex optimization features on top of mountains of other complex optimization features each of which interacts with every other feature in highly complex, non-obvious ways.
Not only were CPUs from both major vendors of AMD64 CPUs (Intel and AMD) affected, despite having completely different microarchitectures. CPUs with completely different ISAs were affected as well. For example, every single Apple Silicon CPU at that time was also vulnerable to a very similar exploit, as were many other ARM-based CPUs as well as MIPS- and POWER-based ones. (In fact, Apple was hit pretty hard with every single Intel-based Mac as well as every single Apple Silicon-based iPhone, iPad, iPod touch, and Apple TV being vulnerable – the only "safe" device being the Apple Watch which at the time did not yet use the same hardware and software platform as the other iDevices.)
So, this does not "just" require a change in hardware, but actually a fundamental shift of priorities in the entire industry.
Spectre and Meltdown were only the beginning, there have been two dozen vulnerabilities and variants in that same family published by now.
However, there are still things that can be done without changing the hardware. Starting from the top of the stack:
User programs
User programs can turn off speculative execution for (parts of) their own code.
Security Libraries
Libraries that deal with sensitive data can implement defenses against having their memory read out.
This may not be 100% perfect and it may not be possible in all circumstances. But doing something is better than doing nothing. There is a reason most of these efforts were labelled as "mitigations", not "fixes".
System Libraries
Similar to the previous point: you can introduce features into the system libraries that mitigate the exploit. This does not help if attackers can run their own statically-linked code which doesn't use the system libraries, but it can help in some situations.
Operating Systems
Operating Systems can implement mitigations such as flushing the Branch Target Buffer between context switches of threads that run on the same physical core.
Virtual Machine Hypervisor
Similar to an OS, Hypervisor can clear / flush caches and buffers on context switches.
Compiler
Changing the compiler to not generate code that would be vulnerable and not generate code that can exploit the vulnerability.
Of course, the second one only works if you can make sure that all code running on the machine is actually compiled by a patched compiler. In other words, it does not protect against the scenario where someone runs some exploit code in a cloud VM and can read out secret data from other VMs. And whether the first one is possible depends on exactly how the vulnerability works on the specific platform.
But it still protects against some other possible attacks. For example, researchers found that they could exploit this vulnerability over the web by specially crafted JavaScript that would be compiled by Google's V8 compiler into code that exploits the vulnerability. In response, Google changed the JIT compiler in V8 to introduce mitigations. Since all JavaScript code running on your machine is always compiled by a compiler that is under your control, you can be sure that these mitigations will always be applied.
An example of this is the retpoline feature in GCC. The basic functionality of that feature was proposed in the original papers about the vulnerability, so pretty much every compiler has implemented some version of this.
The basic idea is to "trick" the CPU into not using the branch predictor but the return stack predictor. So, what the retpoline ("return trampoline") does is to replace a branch with a sequence which places a fake return address on the stack (pointing to a simple infinite loop), calls a subroutine (at which point the code which will be speculatively executed is the infinite loop at the fake return address) which fixes up the return address and returns to the "real" target.
This applies specifically to Spectre variant 2, which is based on the attacker "poisoning" the Branch Target Buffer. Retpolines trick the CPU into not using the BTB, so the part of the CPU which is under the attacker's control is bypassed.
Retbleed
But wait, there's more!
It turned out that return instructions are also vulnerable to a very similar attack. This was published in 2022. And what was it again that we did to mitigate the attacks on indirect branch prediction? Oh, that's right, put returns in there …
So, this vulnerability absolutely smashed most of the efforts to mitigate those earlier vulnerabilities in software.
Microcode
Not all functionalities in modern CPUs are implemented in hardware. In fact, a lot is implemented in microcode, and even functionality which is implemented in hardware can sometimes be overridden with microcode. Microcode is, essentially, just code loaded onto the CPU which can be upgraded and fixed.
The CPU vendors have mostly done three things:

Make changes that mitigate the exploits always, for cases where these mitigations only have minuscule (or no) performance impacts.
Introduce mitigations that can be turned on or off, for cases where theses mitigations have non-negligible performance impacts. That way, for example, cloud providers which run untrusted code from many different users in the same physical CPU cores can turn them on, whereas someone running a render farm running only trusted code can turn them off.
Introduce new instructions that allow user code to protect itself.

Performance
In general the performance impact is higher, the higher in the stack you perform the mitigations. That's why, even if you can mitigate it in software, it should still be fixed in the next CPU generation.
But even when fixing it in the CPU, it is not guaranteed that there won't be an impact. After all, many of these vulnerabilities strike at the very heart of what makes modern high-performance CPUs fast.
All of the above
And, of course, you can combine all of the above. For example, the compiler can use some of the new instructions to generate non-vulnerable code. Kernels, libraries, and applications can publish new versions that have been compiled with the new compiler features turned on. System libraries can provide access to the new CPU instructions using system functions. Applications and security libraries can make use of those new system functions. And so on.
But still … you are right
At the end, though, the industry needs to thoroughly re-think their approach to security as well as their cavalier attitude to the ever-increasing complexity of modern mainstream high-performance CPUs.
Retbleed is a good example. It is a very similar vulnerability to the original Spectre and Meltdown ones, and yet, it wasn't fixed by the compiler tricks, it wasn't fixed by the hardware changes that were made, it wasn't fixed by most of the mitigations, in fact.
Comment: It's only been about 5 years since Spectre was made public, a previously unanticipated kind of vulnerability, so it's not surprising hardware is still finding new cases where the assumption that security of the architectural state was the only thing that mattered, not mis-speculation.  No CPU architect realized there was even the possibility of such a problem until then, so it seems a bit unfair to characterize them as reckless and cavalier, and expect to have had new CPUs designed from the ground up not to have any of that whole class of vulnerabilities (Spectre or MDS).
Comment: Timing side-channels are essentially impossible to close in general, unless you make everything run the slowest it possibly could.  Disabling optimizations every time someone notices that one exists (like https://travisdowns.github.io/blog/2021/06/17/rip-zero-opt.html) isn't a viable path forward for CPU architecture as BeeOnRope points out.  The real problem is trying to strongly isolate tasks from each other including performance effects, despite sharing lots of shared resources.  Most obviously SMT (hyperthreading) where multiple tasks can share a physical core simultaneously.
Comment: One interesting development is Intel's "Data Operand Independent Timing Mode" (DOITM) bit that an OS can toggle. (See [Are any instructions affected by IA32\_UARCH\_MISC\_CTL\[DOITM\] in existing CPUs?](https://stackoverflow.com/q/76309278) for links and comments.)  This could be a way to let CPUs run fast when maximum paranoia isn't needed.  (e.g. when separate security domains aren't sharing the same physical core.)
Comment: @Peter Cordes Superscalar architecture was originally introduced in P6, and that was quite a while back. The fact that Spectre is caused by unintended interference between superscalar and the original memory privilege mechanism and no one spotted it for so long should give everyone pause.
Comment: @MeatballPrincess: out-of-order speculative execution is the key thing, not superscalar.  For x86, superscalar was new in P5, dual-issue in-order.  According to https://en.wikipedia.org/wiki/Out-of-order_execution, IBM S/360 in 1966 was the first processor with out-of-order exec using register-renaming with Tomasulo's algorithm and a scheduler (reservation stations).  POWER1 in 1990 was the first with precise exceptions and out-of-order exec + register renaming.  PowerPC 601 in 1993 (same year as Intel P5, 2 years before P6) was another early OoO exec CPU.  But yes, P6 was an early example.

How do Spectre patches work?


Texmaker unable to compile

Question: I'm trying to compile and run a textmaker document however I keep getting this error even though I have already installed miktex. Any solutions?
Comment: Note that is will also be useful to know exactly which operating system you're using. MikTeX is mostly used on windows, but is also available on other systems where installation can be tricky and this thus often not recommended on those systems.
Answer: The most possible cause of this problem is that MikTeX isn't add to PATH. To solve this problem, you can open the MikTeX Console. There should be a warning, prompting you to add MikTeX to PATH.
As an alternative, you can go to Control Panel, and search for "Edit the system environment variables".

Click on "Environment Variables...".
In the "User variables for [username]" section, double click "Path". Then click "New", and enter the path to your MikTeX installation folder. The default path is C:\Users\[username]\AppData\Local\Programs\MiKTeX\miktex\bin\x64\. (WARNING: it might be different.)
If it still doesn't work, you can consider switching to TeXstudio, which in my opinion is better than TeXmaker.
You can also see this question, for more possibilities.

Texmaker unable to compile


Libre Office spellchecking actions gone after reloading

Question: I'm working on a Libre Office Writer Document where I want to be able to use multiple languages. 10 % of the document are in language X and 90 % are written in language Y. So I set my Writer Language to Language Y and start the spellchecker. Naturally all the words in language X are marked red. So I do 'Ignore All' for each of those words. But as soon as I reload the document (after saving) Writer again marks those words with a red line. What am I doing wrong?
Comment: Why not simply split the document in two, by language? Assuming they're not intertwined...
Comment: The point of the question is my assumption, that the spell check seems to be obsolete. The same problem would happen in a single languge document.
Answer: I'm unsure if you want to completly disable the spell check. It is an odd document and yes there are problems with persisting the spelling vocabulary.
What you can do is choose the Base Language for the spelling check which looks like you know how to do. You can then, by going to Tools -> Options -> Language Settings -> Writing Aids, under user-defined dictionaries you can add your secondary language.
Then, what you do is, as you write, whenever you have the need to write something in the secondary language, once you have typed it, you can select the words with your mouse and leaving them selected you can go over to Tools -> Language -> For Selection and you should have a list of languages to choose from and your secondary language should be there.
This will tell the document that the selected piece of text is meant to be written in this other language and the spelling check will behave accordingly, plus this will persist.
If you reopen the document this will persist, this is assuming that you save it a .odt format, I'm not sure which formats will work with this because that information that persist I beleive would be saved in the contents of the file, so if you were to for example save it as a pure .txt type file, where there is close to no Meta-information within the file's content, this will likely not work, but I can't say I have tested different formats.
If you instead wish to disable the spellchecker for some reason to make things less frustrating that can be gone through:
Tools -> Options -> Language Settings -> Writing Aids

You can disable all of them or as required, you should also check the "live spell check" settings under Autocorrection, called While writing.
At least that way you can write in peace and when you hit a milestone you can enable it again and double check instead of contantly be worrying about that, but the first method is probably the one I would go for.
Hope this is helpful :)
Comment: Thanks that sounds like a good solution. Still I m wondering whether it is possible to tell writer not to double check things that you marked with "Ignore Once" or "Ignore All".
Comment: Hmm not sure, I might be wrong but to me it sounds that is functionanily of the spell checker itself on the writer Application, not on the document, so it wouldn't make sense for that to persist, that function is really just meant be used while you are editing in a short term, not to persist on reopening, that would require additonal meta data to be saved on the document itself to prevent thos ignores to persist (even if they could) for every document.


How can I be as anonymous as possible while on Tor?

Question: I've started browsing the deep web recently and have seen a lot of illegal content. Now while I have no interest in any of the illegal content, I don't want to be caught on one of these sights because of a misclick, clicking on a misleading link, or clicking on an unknown link and get in trouble. Plus I guess I would feel safer being anonymous.
Comment: Read the guide that should be on the first page of Tor about changing your habits also think about using tails
Comment: Also take a look at this article on it, http://lifehacker.com/how-can-i-stay-anonymous-with-tor-1498876762 but this is very extreme
Answer: Use an alternate identity. Browse on TOR using a public connection and computer that is wholly separate from your home network. A VPN to hide your location might be a good idea as well.
Do not mix your identities in any way shape or form.
That will give you the most anonymity.
Answer: I think it is a good idea to use special linux distributions like
Tails

Tails is a live operating system, that you can start on almost any computer from a DVD, USB stick, or SD card. It aims at preserving your privacy and anonymity.

or Whonix

Whonix is an operating system focused on anonymity, privacy and security. It's based on the Tor anonymity network, Debian GNU/Linux and security by isolation. DNS leaks are impossible, and not even malware with root privileges can find out the user's real IP.


How do you reference a dissertation that is turned into a book?

Question: I recently reconfigured my dissertation to publish as a book.  How do you properly cite, reference, or acknowledge the original dissertation (or is that even necessary)? I obviously want to avoid self-plagiarism, but also think it is silly to cite my dissertation at the end of every paragraph in the book.  Any thoughts?
Comment: What do other similar books in your field do?
Comment: In my field (in which publications are normally in the form of journal articles), a dissertation is treated more like a preprint (or a collection of preprints) and not an independent formally published work. In my understanding, citing the earlier preprint version of the article is not necessary. At most the relationship between the two versions might be noted in the acknowledgement.
Comment: Related question: [How to avoid self-plagiarism when adapting dissertation into a paper?](https://academia.stackexchange.com/questions/46022/how-to-avoid-self-plagiarism-when-adapting-dissertation-into-a-paper).
Answer: Assuming that you still hold copyright to the dissertation, it is enough to say, perhaps in the forward to the book, that it draws heavily from the dissertation including long passages taken directly from it, giving a citation to the dissertation.
The important thing is that a researcher is pointed to the original work to get complete context on the ideas including what you don't put in the book.
It is much harder if you have given copyright to someone else, the university or a publisher. Then it isn't a question of plagiarism but of copyright infringement. But some publishers who hold the copyright might permit such things if asked.


VHDL: Simulating Delay for ISE UNISIM components

Question: I have extracted VHDL source of my design from Xilinx ISE.
It uses UNISIM library to model Look-Up Tables and Flip-Flops and other components.
When I simulate my VHDL design (a combinational circuit) using ModelSIM, there are no delays displayed in simulated WaveForms.
I want to know how can I add delay to elements of UNISIM library and then see its effect on MODELSIM simulation?
Comment: There are three types of simulation: (a) behavioral simulation, (b) post map simulation and (c) post place&route simulation. Depending on the type, the tools use different libraries and delay models. Which type do you use?
Comment: I guess I have run behavioral simulation, however how can I run post map simulation in ModelSIM for Xilinx/UNISIM components?
Answer: Each synthesis step generates it's own simulation model. So start start place&route and select 'generate post par simulation model' afterwards. Now you can launch your selected simulator iSim or vSim from ISE.
Answer: You need to attach the generated SDF file when invoking the simulator (On ModelSim : Start Simulation ... / SDF panel")
http://en.wikipedia.org/wiki/Standard_Delay_Format
This file looks like EDIF netlists or LISP code (full of parentheses), its purpose is to tag each primitive with delay parameters.
Answer: The right way to do simulation considering components delay in ISE is to:

Compile simprim and XilinxCoreLib  using compxlib command
Do post-route simulation e.g. (anything other than behavioral simulation have built-in delays involved)


Is email an example of public-key cryptography?

Question: It seems like email is at least analogous to public-key cryptography, the public portion of the key being your email address, and the private portion of the key being the password to the email account. Is this merely an analogy, or is email in fact an instance of public-key cryptography?
Comment: As Neil stated, email is not an instance of PK crypto because anyone looking at the email in transit, or even your email provider, can see the message sent to you. Also there is no way to prove an email sent from you is indeed from you without a digital signature, but this line of reasoning quickly gets blurred by practical concerns. Until you introduce the concept of security or authentication, email is a better initial and intuitive analogy to PK crypto, in the sense that worse analogies (eg. box locked with two keys) are being used.
Comment: No more than your home is an example of Public Key Cryptography. Anyone can mail a package to your home address but only you can receive the package.
Comment: The components being compared are not analogous in that they do not serve the same purposes, or similar processing or similar behaviour in the two systems being compared. I think the link you are making between them is too weak to be called an analogy, but there is a degree of metaphor regarding secret versus published components, and the consequences for the secrecy failing.
Comment: The lockbox analogy is usually used for symmetric encryption or commitments, and it is a little off for public key encryption (everynoe can create the lock, but only the owner has the key to unlock it). However, I think email is an even worse example, since it provides a false sense of confidentiality or is based on wrong assumptions about email. There is no confidentiality for transmission of emails. There is no proof that an email actually came from a certain email address or that the email wasn't tempered with. Email doesn't fulfill any security definition on its own.
Comment: I kinda like that analogy of a house. Especially if you have a mail slot and not a box.
Answer: This is a very abstract and wrong analogy and I assume you are talking about encryption. Often for introducing public key encryption one encounters the "box with lock" example: You publish a box and a lock (your public key) and everyone can put something in the box and close the lock and send it to you. You (the only guy that has the key to the lock  - the private key) can unlock the lock and get the stuff that has been put in there, but no one else ( because you are the only guy with the key to the lock) can do so.
But your email example lacks the main desired feature of this analogy (which is called confidentiality), i.e., anyone who runs your email server or listens in the wire can read all the mails intended to you without the need to know your password. Public key encryption relates the public and private key in a mathematical way (by means of some hard to compute function) such that decryption without knowledge of the private key is computationally infeasible, which is obviously not the case in your example.
Interestingly, identity based encryption does something that comes near to what you describe although cryptographically secure. There your email address (or any arbitrary string) can be your public key. But your private key is not an arbitrary independently chosen password, but some secret that is derived from some trusted party based on your email address. Then, anyone can use your email address to encrypt messages for you and only you knowing the corresponding private key can decrypt.


How is 4G LTE encrypted?

Question: After a few quick searches for 3G security I was able to learn that this standard uses the KASUMI block cipher, of which several weaknesses have been identified (although apparently none of practical use in decrypting 3G traffic?). Anyway, this made me curious - what kinds of security measures are in place for 4G LTE?
Answer: Information regarding the current implementation of "4G" LTE, as well as the soon to be deployed true 4G LTE-A, can be found at the European Telecommunications Standards Institute (ETSI) website and portal.
3G networks use the KASUMI block cipher with the UEA1 confidentiality and UIA1 integrity algorithms. As you said, there have been several demonstrated weaknesses, which has prompted the use of a new cipher / algorithm.
The 4G LTE successor is the SNOW 3G stream cipher and the UEA2 confidentiality and UIA2 integrity algorithms. To quote the specs page:

SNOW 3G is a word-oriented stream cipher that generates a sequence of
  32-bit words under the control of a 128-bit key and a 128-bit
  initialisation variable. These words can be used to mask the
  plaintext. First a key initialisation is performed, i.e. the cipher is
  clocked without producing output, see 4.1. Then with every clock tick
  it produces a 32-bit word of output.
Comment: None of the "weaknesses" in KASUMI are of any relevance to the security of 4G in practice, so talking about weaknesses of KASUMI in this context is (I think) misleading.
Comment: @D.W. According to ETSI, that was one of their reasons for choosing SNOW over KASUMI (I cannot find the direct quote at the moment).
Comment: Unfortunately, it seems that all of the links in this answer are broken. The first 2 return 404's, the last two never loaded for me.
Answer: At a high level, 4G uses symmetric-key cryptography to (1) authenticate the subscriber (phone), and (2) encrypt data sent over the 4G wireless link.
While there have been academic "weaknesses" in KASUMI found, none of them have any practical relevance to the security of 4G in practice.  For instance, one of the known "weaknesses" is a related-key attack.  However, related-key attacks are only of relevance if the system uses the block cipher in an inappropriate way.  4G does not make this mistake, so related-key attacks are of no relevance.  As Wikipedia says, "The authors note that this attack may not be applicable to the way A5/3 is used in 3G systems" (and the same applies to 4G).
The primary weakness in 4G security is that its use of cryptography does not provide end-to-end security.  It only encrypts the traffic between the phone and the base station, but there is no encryption while the data is communicated over the wired network.  This means that there is no security against a malicious or compromised carrier (or a carrier who is sharing all of your data with the local government), and no security for your data when it transits the Internet or the rest of the path.  So, if you want security for your data, you need to do your own end-to-end encryption, e.g., using SSL/TLS, SSH, a VPN, or a similar mechanism.
Comment: I don't think anyone would expect their data to be secured while transmitting over standard HTTP, so I wouldn't call that a weakness of 4G.
Comment: @mgjk, yes, that's right.
Comment: symmetric-key?  i.e. shared secrets?
Answer: To certain extent, LTE provides "somewhat" end to end security. Contrary to what @D.W said, (I am assuming what he meant by wired network is probably core network - i.e. after base stations), 4G/LTE would use Diameter protocol and hence IPSec. So the legacy Signalling System no. 7 (SS7) like core network protocols will be replaced in LTE and hence authentication along with hop-to-hop access control is in place at least as per the specification.
Comment: "This means that there is no security against a malicious or compromised carrier (or a carrier who is sharing all of your data with the local government), and no security for your data when it transits the Internet or the rest of the path" still applies, so your point is moot.
Comment: Yes. For that an attacker not necessarily be a compromised carrier: it would be enough if he has an cracked edge device such as Femtocells. If you have access to core network, one can play around as that is how telecommunication system is built. Its worse in case of SS7, but Diameter is somewhat better is my point.

How is 4G LTE encrypted?


Error: Truffle Box at URL https://github.com/truffle-box/bare-box.git doesn't exist. Even after updating truffle

Question: I am getting the Error: Truffle Box at URL https://github.com/truffle-box/bare-box.git doesn't exist. If you believe this is an error, please contact Truffle support. Even after updating of truffle to 5.1.49.
Comment: @Moosy Do you want to create a Truffle project directory with that?
Comment: Yes I want to create a Truffle project dir
Comment: @Moody I just tried with truffle 5.1.48, node 12.19 and it works. Is your connection behind a proxy? Perhaps it was a temporary network connection issue. Try again if that works or report it to the Truffle project on github.
Answer: You used this URL to get Truffle boxes for a project. There is another method to get them. Moreover, because you mentioned that you want to create a Truffle project i provide this answer to you. However, i think this URL doesn't create a directory. Anyways, you can follow this answer to create it perfectly.

In terminal ,go to your folder or directory you want the project be created there.
Enter the command mkdir projectName. This creates the project directory.
Enter the command cd projectName to go in the project directory.
Now, you need to have Truffle boxes. Get them by entering truffle unbox pet-shop .

By this way, now you have a directory with all required boxes and tools. There are some contracts in contracts folder in the updated project directory that you should replace them with your own contract. And there are some migration js files in migratoins folder that you should replace or set them with your required cases. Also, you can use Truffle document to more and better information.
You should always pay attention to the fact that Truffle boxes are not digitally signed that makes a security warning or error. So, a related error maybe emerges.In this case, you should fix it in your OS.
Good Luck
Comment: @Moody I hope this answer eliminates your problem. Please tell me the result. Thanks
Comment: @Moody Could you create the directory successfully by this guide?


Using sysdate in Cognos Report

Question: My cognos report uses sysdate-n to retrieve records for a specified date. The report execution time varies. Suppose my report runs into the next day i.e past 12:00 am would that mess up records received or do the records retrieved depend only on the time the report was executed?
Comment: Is the value of sysdate set during run time or prior to execution?
Answer: That's a difficult question to answer without seeing how complex the Cognos generated SQL in the report is.
As Sana comment implies, generally the SQL will be executed and the value of sysdate is set during the first hit, however we have seen some very odd logs in the database when there are complex reports where different sections of SQL are executed for different filters - this would mean that when those snippets of SQL run then it might cause problems for you.
If you can post the sql of the report that would help, but probably the best option is to test it out - run the report at 11:55pm and see how the results differ to when run at 12:01am

Using sysdate in Cognos Report


About the speed of light and gravity

Question: I read (I think ) that part of relativity theory is that a strong gravitational field distorts the uniform passage of time. If this is true and a lightwave 'travelling' to Earth  passes a star near its intense gravitational field (a gravity 'lens') does the gravitational field distort the 'timing' of the speed of light and for a small duration of time the light-wave slows a bit until it leaves the influence of the star's gravity? If this is so could you say the speed of light itself was slightly less while the lightwave was passing through the star's gravity?
Comment: Possible duplicates: http://physics.stackexchange.com/q/98980/2451  and links therein.
Answer: We need to be a bit cautious about making over simplified statements in this area because it is a minefield for the unwary. However it is true that as observed by observers far from the star, the gravitional field does affect the elapsed time for objects within it and it also affects the distances travelled by those objects. The net result is that the speed of light does vary with distance from the star.
For more details you might want to look at the questions Photons emitted at the event horizon? and Speed of light originating from a star with gravitational pull close to black-hole strength? for a more detailed discussion of this.
The time dilation is a real effect and has been experimentally measured. In 1971 Hafele and Keating measured the affect of the Earth's gravity on atomic clocks. You ask about this in your comment to user3138766's answer, and the answer is that the time dilation slows everything. If you hovered near a black hole for a while then returned to Earth you would find you were younger than your contemporaries on Earth.
Gravitational lensing is due to the curvature of spacetime. The change in the speed of light in effect changes the refractive index of the space it's travelling through, and this bends the light in an analogous way to the bending of light by a lens.
Answer: Gravitational fields in space distort light. The speed of light is constant, so if light is passing through this gravitational field, it does not slow down but rather time itself relative to the observer, slows down. This is how Einstein explained how the speed of light is constant, regardless of other acting forces.
Comment: If time relative to the observer slows down, would that mean any observable phenomenon in the observer's frame of reference would also slow down? Does the lightwave bend because the gravity distorts the local space-time continuum? Is a distortion in space-time an event    where any time measurements are distorted for any observer?
Answer: Constant $c$ is the framework of entire Relativistic Physics. You start from here. Meaning, any Time Dilation is derived from constant $c$. You can't go in reverse to alter $c$ using Time Dilation.
Think it another way: When you say someone's time is dilated, you actually compare results of own reference frame to the results of that someone's reference frame. For photons, reference frame isn't defined because there's no reference frame in which photons are at rest. So, you can't really calculate time dilation for photons.
Note: This is a strong answer. Any other answer saying different thing is plain simple wrong.
For fun, if you think about Time Dilation for photons, it's already dilated to Infinity whether it's in Gravity well or not (remember, time is dilated due to speed and they have got topmost speed possible). Now, how much further would you like to push dilation using Gravity?
Comment: Relativistic Physics is a great true Theorem and Quantum Mechanics is a great true Theorem. Both have great success with predicting experimental outcomes yet both Theorems have not been resolved as being mutually 'compatible' or consistent I think. Is this part of what the unified field theory is trying to attain? If there is an issue of any compatibility problems between these great theorems might it be that one or both have to be altered 'slightly'?
Comment: @user128932 Any theory can fail in the future. No theory comes with guarantee. Why are you asking this? Your question is concerned about Relativistic Physics. Right?
Comment: What I'm saying is if relativistic physics 'can fail in the future' or it is incomplete maybe the speed of light can be different in certain extaordinary situations. Maybe after the Big Bang in the early Universe c was faster than about 300,000 km/s. There was supposed to be great inflationary expansion of the early Universe. Is Constant c an axiom of relativity physics ?
Comment: @user128932 Yes, constant $c$ is axiom of Relativistic Physics. And, the approach is successful so far to describe the universe (except Quantum Realm).
Answer: Time appears to slow down as light passes a strong object of gravity. Time is not really a physical property, time is simply a unit of measure invented by earthlings.
Time appears to change because gravity bends light and it actually travels further to get to the observer so it takes longer to get there.
Time is actually distance travelled. The light that was headed straight for us was bent and crashed into the source of gravity, the light we see was actually headed at a slight angle away from us and it was then bent toward us taking the longer route.
Answer: If there is an increasing redshift of light as it moves further away from mass and a center of gravity, and a blueshift when light moves in towards the same center of gravity, the only possible explanation is that a photon has to accelerate to match the speed of mass. Since a photon is massless it cannot fall into a gravity well, and without mass a blueshift can only be caused by increased speed.
As a photon is separated from mass and there is a redshift, the conclusion must be that mass has higher speed than light.
If time dilate with increased gravity, remembering that time dilates with increasing speed, gravity would be connected to mass being accelerated to a higher speed than the surrounding space and pulling the fabric of spacetime.
I agree with time being a subjective local perspective of distance travelled, as the only real difference between two points in time is change in position in relation to surrounding bodies in space.
If time is distance travelled, and time dilate with increasing gravity, distance dilate with increased mass because increasing mass is basically an increase in speed. When a photon blushifts approaching mass, it is caused by the acceleration needed to catch up with mass.
Is it possible that light doesn´t move? And the constant property of energy as light, actually is the relation between accelerated mass and static energy, with light being the transformation of energy into mass as it is accelerating?
There is no denying that any mass has the energy of being accelerated to squared lightspeed. No mass is at rest. I see no way around the obvious conclusion that increasing mass is increasing acceleration, and that the energy that is the origin of light is at rest.
Then gravity is similar to the effect on your body as it is pushed against the seat in an accelerating car. Not an attracting property, but inertia of matter in relation to acceleration. More like pressure.
Mass exhibit properties that could be expected from Special relativity if we interpret E=mc^2 literally as mass always being the accelerated state and massless energy stands still. If c^2 is constant, then mass is nothing but a measure of light being accelerated. Isn´t that correct?
It is the only possible solution, since mass is only increase in energy in relation to c. Mass is c accelerating if c is constant without mass.
Gravity must be the inertia of the massless universe interacting with a point where there is a difference in speed of mass and light. The force acts in direction of acceleration, just like gravity acts attracting towards increasing mass.
What is the reason for interpreting E=mc^2 as the energy needed for acceleration of mass to lightspeed squared, instead of accepting the fact that all mass must exist in a state of c^2 since it´s energy is equal to that acceleration?
If mass emerged after the initial expansion of big bang, the acceleration was already achieved when mass condensed in spacetime. The only way mass can have the energy of m*c^2 is if it emerged after acceleration was a fact, since the energy needed for accelerating mass to c^2 is unrealisticly large.
If energy is equal to mass at c^2, then there is no doubt that mass travels at c^2. And gravity must be the difference in energy from the difference in speed between points of different density of mass.Acceleration is movement towards higher density, as time dilate then also distance travelled has to dilate, which must be connected to increasing speed, which makes gravity part of the same energytransformation that is always present in the relation between light and matter. A geometric volume, like a gravity well, seems like a perfect expression of how energy transforms by stretching out(dilating) space time when there is an acceleration directed towards a point in otherwise uniform space.

About the speed of light and gravity


Does WordPress allow me to mark posts as private?

Question: Suppose I want to start a blog.  I would like the "professional" stuff to be public, but the "personal" stuff should only be accessible to friends and family (i.e., accessible only to those users to which I give permission).  Can WordPress do this?
Comment: Seems to me this would be better posted in Webmasters when it goes public.
Comment: Off topic (it wouldn't have been if you ask for a service which allows you to blog, a software you install yourself on your server is).
Comment: Maybe you should rephrase and to make it a bit more specific, I have blog (wordpress, blogger, etc) how can I make it accessible only to those users to which I give permission. I do not see it as off topic as an end user can be a wordpress.com user. `Is the question not appropriate because I'm asking about back-end administration vs. front-end usage? ` Yes it is not appropriate based on the definition of this site from area51. If it is about privacy in posting similar to privacy in posting to say Facebook I would say in that case this question is appropriate.
Comment: @neo: That's an interesting take on this question.  Are CMS not generally web apps?  Is the question not appropriate because I'm asking about back-end administration vs. front-end usage?
Comment: You guys are right.  This wasn't a good question.  Since I can't delete it, I rewrote to better fit the site.
Answer: WordPress for sure. See Set blog content visibility (Classic Editor):

Content visibility is about controlling who can see your blog content. WordPress allows you to control the visibility of your posts and Pages on an individual basis. By default, all posts and Pages are visible.
There are several ways to set the visibility for your blog content. You can set it on a per post/Page basis for public, private, or Password Protected, or make the entire blog private and Password Protected through the use of WordPress Plugins.
Answer: I've used Posterous in this way; I have a public blog and a private blog, and I can mark posts on the public blog as private...


How do I know what patterns to play under a melody?

Question: So I made a melody in my head and translated it to a keyboard. I'm not sure which key it's in but I think it's in D# minor. But I just CAN'T, for the life of me, add a bass to it... I really like this one and I'd love to not cast it aside with all the others. I did my research on arpeggios and stuff and some famous left-hand patterns but I still don't know.
I'd like an algorithm that tells me a good pattern to play under any melody; at least as a placeholder till I find something better. How do I go about learning that? I'm really new to this so please bear with me.
Comment: At the moment, it may be easier theory and playing wise to change its key so it's in, say, D minor for simplicity.
Comment: You seem to have caught a virus: the andalusian cadence! Reading some basics of chord theory will be a short cut to further composing. https://en.wikipedia.org/wiki/Chord_progression
Comment: As a clarification, are you asking how to harmonize the melody -- that is, how to find notes/chords that work well with it -- or are you asking how to arrange those chords into satisfying left-hand / accompaniment patterns ... or both?
Comment: The most usual bass line that many beginners had in mind was  i VII VI V. In d#m this is d#, c#, b, a#. Play it in a minor or em. You will better understand what you're doing.
Answer: This is where your musicianship skills become useful.   (Or where you realise you need some!)
Write down the melody and show it to us as notation.  Then we know what we're talking about.
Hint:  You'll probably find it much easier to notate with an E♭ minor key signature.
I'm really not trying to belittle you.  But if you want to work with music, LEARN THE LANGUAGE!
If I'm misjudging you, I look forward to seeing your melody!
Later....
OK.  You've put some work in.  I'll offer some too!
First thing I did was re-write your tune to make it more readable.  All the notes still start at the same times, but it's easier to read with a key signature (yes, I'll buy E♭ minor) longer note values and without all those fiddly rests.
Then I transposed it down to A minor.  Simply because it's an 'easier' key to think in.   You can transpose it back up of course if you like.
Now, the harmony.  Well, if it's in A minor, I guess Am might be a good first chord.   Yes, that sounds OK.
Now, what's changed in the second bar?  Basically the same melody, but A has moved to G.  What's an Am chord become if the A moves to G?  Yes, a C major chord.  Try it out - yes that's pretty.
We're getting towards halfway in the first 4-bar phrase.  Shall we try a bog-standard sub-dominant moving to a dominant?  That's Dm and E7. Yes, I like that.
The next 4 bars are almost the same as the first 4, with a more elaborate ending.   Exactly the same chords would be boring, let's try another cliche, a 1, 6, 2, 5 bassline.  If we keep it diatonic, you'll see what we get. Maybe you like the Fmaj9 chord, maybe you don't.  Just give it a chance to grow on you. It could alternatively be a C chord as before.
I've spiced the E7 up with the 'Hendrix' ♯9 plus a suspension.  (Ok, I'll be honest.  It fell under my fingers and sounded good.  The analysis came afterwards.)
You've given me just 3 more bars.  OK let's do the same as we started with, but get to the E7 a bit sooner, and I'll add an extra bar to round it off back home on Am.

We could have done other things.  We could have taken that A, G, F, E line from the melody and doubled it as the bass line.  But that's not really adding any value.
Hope I've given you something to think about!
Comment: I can't figure out which type of note to use haha another problem xD
Comment: Okay I added the first page of the melody. It's not full and it changes a little but this should be enough to work with. Now, what did you want to say when you see this?
Comment: I agree with Laurence: look up first some basic chord theory. You can build triads on each degree and learn which patterns and chord progressions are mainstream.
Answer: Here is one trick if you just want to lay down a series of chords under your melody.
Work out what key you are playing in, then write out all the triads (1st, 3rd, 5th) in that key.  There should be seven of them, with one starting on each note of the scale.
Pick a group of notes to lay a chord under.  This could be a bar, but doesn't have to be.  Pick two important notes in that group (but try to avoid two notes that are a 2nd or 7th apart as that messes up this system).  It's entirely a judgement call as to which are the important notes, but an example would be the two ends of a run of notes.
Find the chords that contain those two notes.  There may well be two to choose from.  Try playing each of the chords, and pick the one that sounds best.
For bonus points, use inversions of the chords to avoid the bass line leaping around too much.  If you use a simple triad under the root note of your key, you can produce all the other chords as triads, first inversions or second inversions, barely moving up or down the scale at all.
Answer: This answer is assuming you meant the bass, but the same techniques apply to laying chords beneath your melody with any groove you want
This answer will probably amount to "Music theory is a useful tool in a musicians tool belt, so learn it to speed up your workflow, and to know what to do at certain situations," and while this is true, I don't think just telling you that would be a productive answer, especially because you may already know more than I do.
Here's my step 1
What I always do is create chords first, and then melody, and that way I can use the root of the chords as the bass and I can add groove later. Obviously, you created the melody first, and I think the next best step is to find out the chords beneath your melody before you figure out the bass.
Annnd... step 2
So you should have the chords laid out under your melody now! Now if you know your theory, or how to use google well enough, you should be able to find the root of each chord. At this point, you can make your bass the root of each chord. Your bassline wont have any groove to it or anything, but you have a bass that is 100% technically correct and under most circumstances, won't sound bad.
At this point, you have completed  your "algorithm" for bass, and the next step will bring you to more artistic choices.
Step 3
Now the "groove". Just for clarity, I use the word groove VERY loosely here. By groove I mean the rhythm and note changes that the bass has in order to break up the root note. You said you have done research, and I would apply all of the techniques you have found online using the chords and bass we have come up with in the last step. If none of that works, you can always keep your groove simple, and just one note per chord, or you could have the groove match the rhythm of the melody. You have complete musical freedom so I wouldn't be afraid to try things until they work.
Now we have no clue what genre of music you are working on so I will spare you specific examples of grooves and artistic choices, but one thing that never fails is to listen to other pieces of music in the same genre and just take inspiration from what they do. Pay deep attention to detail when listening as well, because some of the most important things hide in the details.
Answer: Like I supposed in my comment it is the pattern descending from the root of the major scale: la so fa mi. Actually the bass line is integrated in the melody. If you cut the first note of each bar and let it play by the bass you have this line (in a minor A-G-F-E).
Chords accompaniment:
You can keep the primary triad la do mi (d# f# a#).
or you can play the triads of the progression d#, C#, B, A#. Both harmonizations will fit.
It is the most popular progression:

https://en.wikipedia.org/wiki/Andalusian_cadence

But I just CAN'T, for the life of me, add a bass to it... I really like this one and I'd love to not cast it aside with all the others. I did my research on arpeggios and stuff and some famous left-hand patterns but I still don't know. I'd like an algorithm that tells me a good pattern to play under any melody

Here is a list with about 200 songs using the same pattern. Listening to some of them you'll get  some ideas for your research:
https://en.wikipedia.org/wiki/List_of_popular_music_songs_featuring_Andalusian_cadences
Edit:
If you keep the primary triad you'll have (in a- minor):
am am7/G Fmaj7 ?... E
(the dominant of am will be better than am/E.)
The notation in yor melody is unusual: after a 16th note we write first the 16th rest and then the eighth rest.
So you really must learn first the language - like Laurence says. The grammar of triads and the orthography of rhythm. You'll find many easy instructions for beginners about basic theory if you look up chords, rhythm notation, bass riffs etc.


Generate test data bulkly in drupal 8

Question: I setup a website based on Drupal8,create some content type(with several fields),Now I want to enter some test data in my site.
How can I generate test data bulky in drupal8?
Answer: Devel module will Do it for you and happy Devel module is ported to Drupal 8 https://www.drupal.org/project/devel
Enable Devel and Devel Generate
go to "<code>/admin/config/development/generate/content</code>" give the number of content it will generate bulk content for you.
Comment: but when I have video file `Error: Class 'Drupal\video\Plugin\Field\FieldType\Random' not found in Drupal\video\Plugin\Field\FieldType\VideoItem::generateSampleValue() (line 1` .

Generate test data bulkly in drupal 8


Doubt about Cauchy-Lipshitz theorem use

Question: I'll show my doubt with the Cauchy problem $\begin{cases} y'=1+y^2  \\ y(0)=0 \end{cases}$. I know the solution is $y(t)=tg(t)$, but let's say I don't know the explicit solution. If I look at $1+y^2$, then I have all the hypothesis for the application of Cauchy-Lipshitz Theorem in $[0, 2\pi]$ for instance, because it is lipshitz there (or not?). So I have a unique solution in $[0,2\pi]$, but now if I wonder if I can prolong the solution, how can I understand that in fact I cannot prolong the solution to $2\pi$ but at best to $\pi/2$ without solving  the differential equation?
I mean, where do I commit a mistake in using the Cauchy-Lipshitz Theorem? If you have some other (not simple like mine) examples that have the same problem, I would like to see how to solve them in the right way. Thanks for the help.
Comment: The right hand side $1+y^2$ is indeed Lipschitz continuous for $y \in [-M,M]$ for any $M$. (note that right hand side does not depend on $t$). But the Lipschitz constant goes to infinity if $M \to \infty$. Therefore the solution is indeed unique, but it could go to infinity in finite time, just as $y = \tan t$ does.
Comment: Sorry, could you explain it? I don't understand why it can go to infinity finite times. I mean, the theorem states that I have a unique solution defined on all the interval (which is $\mathbb{R}$ in this case), but $tg(t)$ is not always defined. What am I missing?
Comment: @tommy1996q, false. You have only *local* existence: https://en.wikipedia.org/wiki/Picard%E2%80%93Lindel%C3%B6f_theorem.
Answer: Here is the statement of Cauchy-Lipschitz:
Suppose we are given an ODE, $$y'(t) = f(y(t)), \ \ \ \ \ \ \ y(0) = y_0,$$
where $f$ is a real function defined for $y \in [y_0 - b, y_0 + b]$, obeying the boundedness condition
$$ |f(y)| \leq  m,$$
and obeying the Lipschitz condition
$$|f(y_1) - f(y_2)| \leq k |y_1 - y_2 |.$$
Then for any
$$a < \min \left(\tfrac b m, \tfrac 1 k \right),$$
there exists a unique solution $y(t)$ to the ODE, valid for $t \in [-a, a]$, with $y(t)$ taking values in the range $[y_0 - b, y_0 + b]$.
Note that Cauchy-Lipschitz does NOT give us a solution for all values of $t$! It only gives us a solution for $t$ in the range $[-a, a]$, where $a$ is restricted by (i) the range of $y$ on which $f(y)$ is defined compared to how big $f(y)$ gets on this range of $y$, and by (ii) how "contracting" the function $f(y)$ is.
Let's now apply this theorem to our ODE. In our ODE, $f(y) = 1 + y^2$ and $y_0 = 0$. For the time being, let us fix a value of $b$ (so we are looking for solutions such that $y(t)$ always stays within the interval $[-b,b]$ at all values of $t$.)
On the interval $[-b,b]$, we have
$$ |f(y)| \leq 1 + b^2,$$
so $|f(y)|$ is bounded by $m = 1 + b^2$. Furthermore,
$$ |f'(y)| = 2|y| \leq 2b,$$
so, by the mean value theorem, we learn that $f$ is $k$-Lipschitz with $ k = 2b.$
Taking $$a < \min \left( \tfrac{b}{1 + b^2}, \tfrac 1 {2b} \right) = \begin{cases} \tfrac{b}{1 + b^2} & b \in (0, 1); \\ \tfrac 1 {2b} & b \in (1,\infty),\end{cases}$$ Cauchy-Lipschitz tells us that there exists a solution, valid for $t \in [-a, a]$, which takes values within the range $y(t) \in [-b,b]$.
The largest possible bound on $a$ is obtained when we take $b = 1$: in this case, we learn that there exists a solution valid for $t \in (-\tfrac 1 2, \tfrac 1 2)$ (and this solution takes values in the range $y(t) \in [-1,1]$, though this is less interesting).
In fact, the solution is
$$ y(t) = \tan t,$$
which is valid for $t \in (- \tfrac \pi 2, \tfrac \pi 2)$. So our method of applying Cauchy-Lipschitz has given us an under-estimate for the range of $t$ on which the solution is valid.
Comment: I have looked at the wiki page of the theorem and I think I got it now. Long story short, the proof is based on a contraction, and the values $b/m$ and $1/k$ are needed because the former makes you fall into the interval you chose for $y$, while the latter gives you a contraction. Thank you very much, you helped a lot.
Comment: I think I have understood now. Tell me if I'm wrong. The problem is that I have local existence, so once fixed $b$, that is the maximum variability of $y$ allowed, I am bound to take $a$ like that, and the interval I described couldn't be used for the theorem. Just one thing, I knew you needed local lipshitz for $y$ and uniform continuity for $t$, never heard about finiteness of $f$, is this hypothesis equivalent to the uniform continuity in this case?
Comment: @tommy1996q Yes, that's exactly right! :-)
Answer:
So I have a unique solution in $[0,2\pi]$...

False. We have only local existence:

$$\cdots$$
Then, for some value $\epsilon > 0$, there exists a unique solution $y(t)$ to the initial value problem on the interval $[t_0-\epsilon ,t_0+\epsilon]$.

Doubt about Cauchy-Lipshitz theorem use


How does the jiva or soul control the body?

Question: Are there any scriptures about this? For instance, how would a jiva move the arm of the body, or walk?
Answer:
Whatever action a man performs with his body, speech and mind whether right or the reverse these five are its causes.Bhagavad Gita 18.15 Translation Swami Gambirananda

For moving the hand or walking (as in instance) , the five stakeholders are Golaka(physical gross organ), Indriya (corresponding subtle organ),Antahkarana(Mind),Prana(Vital energy), Daivam(Presiding deity .. Past karma.. other forces of nature .. that which is incalculable).

अधिष्ठानं तथा कर्ता करणं च पृथग्विधम् ।
विविधाश्च पृथक्चेष्टा दैवं चैवात्र पञ्चमम् ॥

Adhisthanam, the locus, the body, which is the seat, the basis, of the manifestation of desire, hatred, happiness, sorrow, knowledge, etc.; tatha, as also karta, the agent, the enjoyer [The individual Self which has intelligence etc. as its limiting adjuncts, due to which it appears to possess their characteristics and become identified with them.] who has assumed the characteristics of the limiting adjuncts; prthak vidham, the different kinds of; karanam, organs, the ears etc. which, twelve [The five organs of knowledge (eyes, ears, nose, tongue and skin), the five organs of actions (hands, feet, speech, organ of excertion and that of generation), the mind and the intellect.] in number, are of different kinds for the experience of sound etc.; the vividhah, many; and prthak, distinct; cesta, activities connected with air-exhalation, inhalation, etc.; ca eva, and; daivam, the divine, i.e. the Sun and the others who are the presiding deities of the eye etc.; is atra, here, in relation to these four; pancamam, the fifth-completing the five.Sri Shankaracharyas commentary ,Translation Swami Gambirananda.BG 18.14

Sarva vedanta sidhantha Sara sangraha , Sri Shankaracharya , Verses 420,421,422 Translation Swami Tatvananda RK mutt

Presiding deities avail
themselves of the various sensory
organs to hinder or to help one's
progress. All that depends upon
the nature of one's past actions.(svsss 420)(anugraha or nigraha of devatas is a factor)

Therefore, these five viz, thebody, the senses, the vital breath,
the ego, and the various presiding
deities should all the regarded as the ultimate cause of all that is performed. (svsss 421 , as in BG 18.4)

It is according to the bent of
one's past actions that the gunas make themselves manifest. The inclination of the mind in its turn, follow the gunas. That is how both the organs of knowledge and
those of action impel a person
here on earth to perform various
kinds of actions, both those that are meritorious and those that are sinful.(svsss 422)

PS :
Sri Shankaracharyas commentary, Brihadaranyaka upanishad 4.3.7 Translation Sri SN Saastri

Just as an emerald or any other gem, dropped into a vessel of milk, imparts its lustre to the milk, so does this luminous self(atma), being subtler than even the mind and the intellect, impart consciousness to the whole body, mind and organs. (When an emerald is dropped into milk, the latter gets a green hue. Similarly, the self, being pure consciousness, makes the insentient mind, body and organs sentient.)


Hardware recommendations for heavy beam mounted to wall

Question: I am forging 3 mantel brackets out of mild steel for a 99"x 9" x 4 1/2" old barn timber that weighs 90 lbs.  What type of hardware would you recommend to secure it to the studs?  Each bracket will have 2 holes on the vertical run to attach to the wall/stud and will be 1/4" thick.  I can get #20 (5/16 shank) pyramid head wood screws that are 2 1/2" long.  Or, should I go with a 3/8" to 1/2" lag bolt?  What would be an ideal length for these?
Comment: I would go with a structural wood screw instead of the lags.
Comment: _That_ is a _big_ mantle! That will look excellent whether you put a finish on it or hang it exactly as is!
Answer: I think your choice of 5/16" size lag screws, 2-1/2" long, is fine.  I would say 3/8" is overkill but if you just like the look of the bigger fastener, it would be fine.
I'd actually use something a little smaller, but longer - 1/4" size, and 3" long. (And washers, whatever size you use, I'd use washers.)  One of those is adequate to support 90#.  I'd also drill a pilot hole, 3/16" bit works well for 1/4" fasteners in most wood.
Comment: I want to use the 2 1/2" because they are decorative and I won't have to make them.  I wish they had some longer ones though.  I have to find out if the client has drywall or not but even so, if the drywall is 1/2" and the bracket is 1/4', I'll still have 1 3/4" penetration into the stud with a 5/16".  So hopefully these will still be okay.  Thank-you!


Book series about a boy who runs away from his walled city and finds his sister in a hidden city in the wasteland outside

Question: I can't for the life of me remember the book series. A boy and his brother live with their father in a world where there are clusters of cities and everyone outside of them lives in poverty and disease. He eventually meets his sister and he joins the circus act in it.
Answer: Are you thinking of Pure by Julianna Baggott?  But there isn't a circus, and I'm pretty sure you would remember a dome instead of clusters of cities.
Comment: No I`m sorry thats not it, his brother joins their worlds version of the army and eventually destroys the city at the end of the first book, the cover was a triangle with swirls at each point.


How often do artifacts appear in Temple Run 2?

Question: Do artifacts appear based upon time, distance run, or something else like that? Also I've noticed I seem to get artifacts faster when there are holiday artifacts to collect. Is that also a variable? If anybody knows the spawn rate of artifacts that would be nice.
Answer: My experience is that artifacts appear based upon distance but I do not know more specifically than that.  There can only be one chest grabbed per run, but if you miss the first one, other chests will continue to appear intermittently until you successfully jump to grab one, after which no more chests will appear that run.
I have also noticed that when there is an uncompleted holiday artifact quest, the rate of chests seems to increase until the quest is completed.  My experience is that once the relevant holiday quest is completed, the chests revert to containing ring and mask artifacts only with no more holiday artifacts appearing.
Edit: to add some data to this, I worked out for a game that has been played entirely since the introduction of artifacts that there were a total of 78 artifacts found over 1.7 million meters, giving a rate of about 1 every 22k meters.  I think powerups appear about once every 750 meters or so, so assuming that about 80% of those chests that appear are grabbed, that gives a rate of 1 in 25 powerups being a chest.  That includes periods when there were holiday quests active and not active, and it includes gameplay before the  Pickup Spawn was fully upgraded, so that is good to keep in mind.  Since long runs can have at most one chest, that pushes the average downward.  Perhaps for the initial chest it is something like 1 in 10 during the holiday quest active period, and 1 in 20 when there isn't a holiday quest active, if indeed they appear at different rates.
Comment: Update: I think that early on in the game, the chests appear more frequently.  I started from scratch on a new tablet and it seemed like there were more than one chest every 22k meters, so maybe the incidence is increased when the player is a low level.  I didn't think to measure it carefully and now I'm back to level 9 again and seeing about the same frequency as listed above.  (this game, about 100 items in 2 million meters is about 20k meters per item, with some long runs in there and some missed jumps.)
Comment: Another update: I haven't conducted experiments yet, but I think that the December 2014 update affected the rate of chest appearance.  That is, they seem to be more common now.
Answer: I have noticed that the number of chests increase when a holiday quest is available. Also, I've noticed that when a holiday quest is going on, it is more likely to get an artifact you already have.
It is difficult to get the last ring artefact because it is less likely to be in chests than other artifacts such as holiday artifacts and floral artifacts, so it's more likely that your going to get those hats before you get the other hats.
When you unlock a hat, you can equip it to your character, and you can have it equipped to more that one character, but it's more common the most of your hats or your hat is a holiday hat because, since these special quests are out for a while, but not forever like the other quests will be.


How can you reset / restore localstorage using Cucumber/BDD

Question: I am writing a HTML5 / Backbone.js application which will store data using localstorage. I would like to BDD this application using Cucumber, but can't figure how to reset localstorage between tests, and in particular setup certain data before certain tests.
The only way I can do this is to maintain several Firefox profiles, each with their own state of local storage, and use these profiles dependent on what tests to run, but this seems quite brittle, complex and slow.
Any ideas?
Answer: this should help you problem :
<code>describe 'Favourites View ', ->
  beforeEach ->
    localStorage.clear()
</code>


My story moves too fast

Question: I finally sat down and wrote the first chapter of my planned novel. Reading back through it, I realized that there is so much that happens in only 2000 words. People die, the protagonist is captured, dialogue happens, but it all happens so fast, one event after another. How do I write in a more expansive way?
Comment: How many chapters like that do you have planned?  If you've got 32 of those breakneck-speed chapters planned out, then your plans are probably too complicated.  You wouldn't write a historical novel that covers 2000 BC to 2000 AD.  (Unless you're James Michener!)  Besides, you need to leave room for sequels.
Answer: 1) Don't worry about it for this draft.
Write your entire book. Get it down on paper. Then put in a drawer for a month.
Then, when it's finished and you have a little distance, you can go back and see where there's room to insert other scenes and slow events down. You don't want to kill the momentum of your writing by spending so much time fussing over editing.
The first draft will by definition be rough. That's fine. As you are writing the book, plots and bits of character information will come to you which you didn't have planned. These can be part of what you can use to slow things down in the editing process. But you can't discover those things until your book is written.
2) When you are editing and you need to insert things:
Take the time for descriptions. Describe the setting. Make sure there are little character moments to show the reader what your world and your characters are like. Give us a sense of how people speak, of the smell of the air, the composition of the buildings. Show us the technology. Show us affiliations of politics, geography, religion, race, marriage, and family.
When an event happens (someone is captured), show us the reactions of the other characters. Let us see how the ripples of this event are starting to spread outward (particularly since that's what's going to move your plot forward).
Comment: I would also add two things. Firstly, while you definitely need Lauren's second point, don't overdo it. Pages of description and setting (unless done right) will bore. Make sure whatever the reader wants to read is there in plenty (this may not be action - it's just what the reader wants to read). Secondly, **drafts do not work for everyone.** I am finding that I cannot - and indeed apparently do not need to - write drafts. I believe I am in the extreme minority in this matter, however.
Comment: @TommyMyron Gosh, hi, Ms. Cartland! Nice to see you with us again! ;)

My story moves too fast