Will a compromised cable modem inherently compromise any router connected to it under any router config?

Question: I'm planning on setting up a network with a custom-built router with pfsense. If I assume the cable modem connected to the router is compromised can a properly configured router ensure security or do I need to turn my custom router into a custom cable modem? I'm only concerned about my data sent and received through the modem being read unencrypted or the modem having access to my LANs on my router.
Answer: A compromised modem would only be able to compromise the router if it can exploit some vulnerability in the services that are exposed to it (which should be minimal, because there's no reason to expose the administrative interface on the WAN side of the router). Alternatively, if the router did anything insecure like installing updates of unencrypted HTTP, then those could be intercepted and modified (using something like evilgrade.
However, it will be able to intercept and modify any traffic that flows though it. If all that traffic goes down a properly configured and encrypted VPN tunnel then there would be fairly limited scope for attacks (although it could still gather metadata, or cause a denial of service).
It's basically the same position as having an untrusted ISP or being connected to a dodgy wireless network - as long all your traffic is well encrypted and you have mutual authentication, it's hard for them to directly compromise you.
Answer: If the modem is a separate device being connected via Ethernet or some serial link, then Gh0stFish's answer holds (all the modem could do is tamper with unencrypted traffic or exploit a vulnerability in some protocol parser), but if the modem is in the form of a PCI or PCIe card in the router (which is very common with modem routers), then all bets are off. Most routers do not have the hardware necessary to protect against DMA attacks by devices on the PCI bus, and a PCI modem may be compromised through a malicious firmware update using TR-069.
If the modem is connected using Ethernet, PPP, or something similar and the traffic is encrypted and authenticated (i.e. not vulnerable to MITM attacks) and the router's network drivers are not seriously outdated and vulnerable, you should be fine.


Do the septons and septas of the Seven have magic powers?

Question: In Game of Thrones, the priests of the Red God and the Old Gods of the Forest exhibit magic powers. Do the devotees of the Seven exhibit similar power?
Comment: possible duplicate of [Are any magical acts ever claimed on behalf of The Seven?](http://scifi.stackexchange.com/questions/47005/are-any-magical-acts-ever-claimed-on-behalf-of-the-seven) The other question is newer yes, but is broader, asking about magic generally, not just the septons/septas. It also asks about the Drowned God.
Comment: The priests of the Drowned God can also have visions...
Answer: If they do, they are considerably more subtle powers than those of R'hllor and the Old Gods. During my re-reads of the A Song of Ice and Fire series I have seen no such overt examples of magic powers. It would seem most of their power is non-magical, in the sense that they have many (zealous) followers, martyrs and a strict code of conduct.
In A Feast for Crows there is a chapter when Brienne and her small party visited the Quiet Isle, where believers of the Seven go to atone for their sins. The Elder Brother there had an aura of mysticism about him, was said to be a great healer and did... (Mystery Spoiler)

...apparently heal Sandor "The Hound" Clegane from his wounds, and his volatile personality. The Hound is dead, he said, but what he meant was that Sandor Clegane was purged of his evil persona called "The Hound".

When I read this chapter, I get a sense of mystery and magic surrounding the Quiet Isle, but of course it is nothing as explicit as the miracles performed by R'hllor.
The stories told by the Elder Brother are fascinating. At one point, I was wondering if he was someone important, since he said he had been at the Trident when Rhaegar and Robert met, and that he "died" there, and was reborn on the Quiet Isle.
More on topic, it has been said that the Silent Sisters - an order of the Faith of the Seven - have the power to speak with the dead. But no such thing has been demonstrated, and moreover, the Silent Sisters have sworn vows of silence, so it would be a one-way communication.
Comment: @BinaryWorrier Oh, I'm sure you do. It is the place where they have to go through a swamp-maze to enter, where Brienne has a long talk with the Elder Brother about her quest, the Hound, Sansa, and she confesses everything to him.
Comment: No, I even looked up the Wiki on the Quiet Isle and I'm still drawing a blank. I've read the first 3 books several times, but I met my wife around the time Feast was published, and my time hasn't quite been my own since :) - but in a very lovely way, obviously. Now that I've been Kindled I could pick up e-copies and peruse them again :)
Comment: @BinaryWorrier *Feast* is a difficult read, I think. At times, it is boring, but the great value of the book is its many references to backstory, most of which is told by Maester Aemon. If you've read the Dunk & Egg novellas, its even more interesting.
Comment: +1: I may have a re-read of the books, I have no memory of the Quiet Isle!
Comment: It is important to point out that all religions that show "magic" powers are somewhat similar. For example the old gods have weirwood paste to induce prophetic dreams while the warlocks have shade-of-the-evening to do the same.
Answer: In the books, the question on the existence of magic is a recurring theme. Most characters don't believe in magic, and the beginnings of the books don't lend much credibility to hedge wizards and the like. After a while though (end of first book/season) it becomes obvious that something is going on.
While the followers of R'hllor exhibit the flashiest and most powerful "magic", the other religions should not be counted out. In particular, the Old Gods and the House of Black and White seem to have followers with special powers. Furthermore, there are many other religions that may or may not exhibit these types of powers in times to come (Drowned God, Starry Wisdom, etc.)
With regards to the Seven, I think the strongest example yet actually isn't Quiet Isle, but is Davos' conviction that the seven kept him alive so that he could stop Melisandre's corruption of Stannis.
Answer: The "powers" that any of the religions have in the series can be best explained via Varys' anecdote about "the sellsword in the middle." The Faith of the Seven, in particular, gain their power from the people as the people perceive them as powerful. As far as any one religion being more powerful than an other, it's clear that there is a "force" (lack of a better word) within the metaphysics of the story that can be accessed by a character(s) consciousness.
Remember, GRRM hated the ending to LOST and proclaimed his disdain for it, so following that logic one can deduce that the "magic" won't be "other-worldly" and instead will revolve around a responsible agent, thus avoiding the writers cop-out of the Deus ex Machina.
Answer: One concrete example was Cats visit at Renlys camp and visiting the sept.
There she was given guidance, but was too thickheaded to pick up the hints or act on them.
ie saw Arya as the warrior. But not in the stranger! (ie she will always be a someone ;) )
Saw Cersei as the mother
Saw both Rickon and Bran needing their mother, and Robb requiring her presence too.
So yes, very subtle. No wonder one needs a clear conscience to be able to pick up the hints or act on them. And thus the punishments for sins are very much appropriate. Otherwise the seven are just painted idols to you.
Comment: Brilliant answer! But can you quote from the books?
Answer: No the clergy of the Seven have never displayed any magical abilities so far in the series.
The event about Hound has got to do more with the personal skills of the Elder brother rather than his magical powers. He got even someone as reserved and shy as Brienne to open up to him. He is a former warrior who found his peace at the monastery so naturally other lost warriors such as Sandor and Brienne can relate to him in certain manners, in order to give themselves hope of peace if nothing else.
As for Silent Sisters' powers to talk to the dead, while admittedly it has been stated in the books, it has never been stated as a fact. It has always been a rumor, a fantasy.
There have also been two instances of clergymen, who supposedly performed miracles. One was Septon Murmison, who if could have performed miracles by praying, might have done himself a lot of good by praying for the right temperament for managing the realm as Hand of the King. The second one was the eight years old boy who was made High Septon on King Baelor's insistance, as the King claimed that the boy could perform miracles. Yet, when the King had finally brought himself close to death in his final fast, the boy couldn't perform a miracle to save his life.
TLDR, there is no evidence that the clergy of the Faith have any magical powers. And given the lack of evidence, we can assume that they in fact have no powers at all.


What are the historical reasons that France adopted civil rather than common law?

Question: The story I heard is that revolutionaries thought that judges were corrupt and thus should be left to interpret the law, and thus should closely follow codified rules. Is that historically accurate?
Comment: I'm voting to close this question because history questions belong on https://history.stackexchange.com/
Comment: @BlueDogRanch no, the history of law is on topic here
Comment: This is history of French politics, though, not French law - the changes were led by sociopolitical reason, not legal reason.
Comment: I have to agree with @DaleM. What do people get from deletionism? If you don't find a question of interest then just skip it over. Why do you have to advocate for the elimination of something that others may find of interest, and think up reasons to support why it should be deleted or ejected from the site? It would understand if it had nothing to do with legal systems at all but some very rich discussions of legal history have been had here and I was very grateful to have read them.
Answer: Yes.
France invented the civil law system and adopted it in connection with the French Revolution. Napoleon commissioned it in 1804.
The summary of the story is here. As Wikipedia explains:

Before the Napoleonic Code, France did not have a single set of laws;
law consisted mainly of local customs, which had sometimes been
officially compiled in "custumals" (coutumes), notably the Custom of
Paris. There were also exemptions, privileges, and special charters
granted by the kings or other feudal lords. During the Revolution, the
last vestiges of feudalism were abolished.
Specifically, as to civil law, the many different bodies of law used
in different parts of France were to be replaced by a single legal
code. The Constituent Assembly, on 5 October 1790, voted for a
codification of the laws of France, the Constitution of 1791 promised
one, and the National Assembly adopted a unanimous resolution on 4
September 1791, providing that "there shall be a code of civil laws
common for the entire realm." However, it was the National Convention
in 1793 which established a special commission headed by Jean-Jacques
Régis de Cambacérès to oversee the drafting process. His drafts of
1793 (for which he had been given a one-month deadline), 1794, and
1796 were all rejected by a National Convention and Directory more
concerned with the turmoil resulting from the various wars and strife
with other European powers. The first contained 719 articles and was
very revolutionary, but was rejected for being too technical and
criticized for not being radical or philosophical enough. The second,
with only 297 articles, was rejected for being too brief and was
criticized for being a mere manual of morals. The third, expanded to
1,104 articles, was presented under the Directory, a conservative
regime, but never even came up for discussion.
Another commission, established in 1799, presented that December a
fourth scheme drafted in part by Jean-Ignace Jacqueminot (1754–1813).
Jacqueminot's draft, the so-called loi Jacqueminot, dealt almost
exclusively with persons and emphasized the need to reform the
Revolutionary divorce laws, to strengthen parental authority and
increase the testator's freedom to dispose of the free portion of his
estate. It was, of course, rejected.
Napoleonic reforms
Napoleon set out to reform the French
legal system in accordance with the ideas of the French Revolution,
because the old feudal and royal laws seemed confusing and
contradictory. After multiple rejected drafts by other commissions, a
fresh start was made after Napoleon came to power in 1799. A
commission of four eminent jurists was appointed in 1800, including
Louis-Joseph Fauré and chaired by Cambacérès (now Second Consul), and
sometimes by the First Consul, Napoleon himself. The Code was complete
by 1801, after intensive scrutiny by the Council of State, but was not
published until 21 March 1804. It was promulgated as the "Civil Code
of the French" (Code civil des Français), but was renamed "the
Napoleonic Code" (Code Napoléon) from 1807 to 1815, and once again
after the Second French Empire.
The process developed mainly out of the various customs, but was
inspired by Justinian's sixth-century codification of Roman law, the
Corpus Iuris Civilis and, within that, Justinian's Code (Codex). The
Napoleonic Code, however, differed from Justinian's in important ways:
it incorporated all kinds of earlier rules, not only legislation; it
was not a collection of edited extracts, but a comprehensive rewrite;
its structure was much more rational; it had no religious content, and
it was written in the vernacular.
The development of the Napoleonic Code was a fundamental change in the
nature of the civil law system, making laws clearer and more
accessible. It also superseded the former conflict between royal
legislative power and, particularly in the final years before the
Revolution, protests by judges representing views and privileges of
the social classes to which they belonged. Such conflict led the
Revolutionaries to take a negative view of judges making law.
This is reflected in the Napoleonic Code provision prohibiting judges
from deciding a case by way of introducing a general rule (Article 5),
since the creation of general rules is an exercise of legislative and
not of judicial power. In theory, there is thus no case law in France.
However, the courts still had to fill in the gaps in the laws and
regulations and, indeed, were prohibited from refusing to do so
(Article 4). Moreover, both the code and legislation have required
judicial interpretation. Thus a vast body of case law has come into
existence. There is no rule of stare decisis
Answer: prussia

The story I heard is that revolutionaries thought that judges were corrupt and thus should be left to interpret the law, and thus should closely follow codified rules. Is that historically accurate?

For Prussia, where the General State Laws for the Prussian States (PrALR) came into force in 1794, this would be accurate.

Protokoll Friedrich des Großen [II] vom 11.12.1779
Darnach mögen sich die Justiz-Collegia in allen Provinzen nur zu richten haben, und wo sie nicht mit der Justiz ohne alles Ansehen der Person und des Standes gerade durch gehen, sondern die natürliche Billigkeit bei Seite setzen, so sollen sie es mit Sr.K.M. zu thun kriegen. Denn ein Justiz-Collegium, das Ungerechtigkeiten ausübt, ist gefährlicher und schlimmer, wie eine Diebesbande, vor die kann man sich schützen, aber vor Schelme, die den Mantel der Justiz gebrauchen, um ihre üblen Passiones auszuführen, vor die kann sich kein Mensch hüten. Die sind ärger als die größten Spitzbuben, die in der Welt sind, und meritiren eine doppelte Bestrafung.

Minutes of Friedrich the Great [II] of December 11, 1779
Therefore the judiciary colleges [judges] in all provinces may only give judgements, and where they do not go straight through with the judiciary without any regard for person and status, but put natural equity aside, they will have to deal with His Majesty. For a judiciary that practices injustice is more dangerous and worse than a gang of thieves, one can protect oneself from them, but no one can guard against rogues who use the cloak of justice to carry out their evil passions. They are worse than the greatest rascals in the world and deserve double punishment.

On the 14th of April 1780 Friedrich II commissioned the new law which was compleated in 1792.

Auf Meinungen der Rechtslehrer, oder ältere Aussprüche der Richter, soll, bey künftigen Entscheidungen, keine Rücksicht genommen werden.

In future decisions, no consideration should be given to the opinions of the legal teachers or older statements of the judges.

§ 6 der Einleitung zum PrALR

In some areas, certain portions of this law is still used today.
The last case known to me was in 2011:

Zivilkammer des Landgerichts Neubrandenburg vom 15. September 2011 - 1 S 100/10

Essay in English: Allgemeines Landrecht für die Preußischen Staaten (ALR) - Max-EuP 2012
1. Historical background
Allgemeines Landrecht für die Preußischen Staaten (ALR) of 1794 (Prussian territorial law), the French Code civil of 1804, and the Allgemeines Bürgerliches Gesetzbuch (ABGB) of 1811 (Austrian civil code) emerged towards the end of the age of enlightenment and the natural law movement. Together, they are the natural law codes (Naturrechtskodifikationen) and the first modern European codifications.
...
2. Origin
...
Frederic II became increasingly discontent with Prussia's judicial system. Yet, his new Grand Chancellor Carl Joseph Maximilian Freiherr von Fürst und Kupferberg did not meet his requests for reform. As a result of the famous Arnold case - Frederic II believed that the rights of the miller Arnold were infringed by partial judges - Frederic II released Fürst in 1779 from his office and appointed Johann Heinrich Casimir Graf von Carmer as his successor.
...
4. Content
The ALR consisted of 19,194 sections. Prima facie, it appears to be very voluminous. However, in contrast to the Code civil and the ABGB it contained the entirety of private law, the entirety of public law, including constitutional law and criminal law, and it contained also feudal law.
...

Sources:

Allgemeines Landrecht für die Preußischen Staaten – Wikipedia

Müller-Arnold-Fall
General State Laws for the Prussian States - Wikipedia
Essay in English: Allgemeines Landrecht für die Preußischen Staaten (ALR) - Max-EuP 2012

Allgemeines Landrecht für die Preußischen Staaten (01.06.1794)

Einleitung (in German)
Erster Theil (in German)
Zweyter Theil (in German)


UAC: Autohotkey calling the Windows 10 command window; es.exe by Voidtools Everything

Question: New readers please (just) read my second edit.
(Original title: "UAC: Cannot use the command window anymore with Autohotkey (Windows 10)", intermediate title: "UAC: Cannot run es.exe (Voidtools Everything) in the command window from Autohotkey anymore (Windows 10)")

In the past, I have used the command window with AHK; this is not possible anymore, without UAC interfering. Seems there have been "updates" with the most recent W10 (and/or AHK?) update(s).
Even very simply things are not possible anymore, the AHK help is not understandable ( https://www.autohotkey.com/docs/commands/Run.htm ).
I run the following AHK command, always from an administrator account:
runwait, %comspec% /c dir c:\ >>d:downloads\000.txt, , min
(This is identical to an example in the linked help file, except for the fact that in the example, they write the output to c:\, and I want to de-complicate things as much as possible.)
This just opens the command window but does not write any command to it, and thus, there is no output. (You can verify this by leaving the command window open, without the /c attribute: runwait, %comspec% dir c:\ >>d:downloads\000.txt, , min )
So, I have to write
runwait, *runas %comspec% /c dir c:\ >>d:downloads\000.txt, , min
This is as before, except for the *runas "key" as they call it. With this, there is "success", incl. the writing of the output, BUT this command first opens the UAC dialog, which asks, "Do you want to allow the app to make changes to your device?", the only "change" obviously being the writing of the output file; the same would occur if I just piped the output to the clipboard, or if I triggered another program which would just display its help within the command window.
It is obvious that for such things, nobody would want to have to interact with that UAC dialog, but would simply have done this automatically, in order for the output then to be further processed.
Thus, I tried by changing my security settings in the UAC (in the UAC dialog, there is "Show more details", and when you click that, you can read, "Change where these notifications appear", clicking on that then bringing up a slider) from 4/4 to 3/4, then 2/4, then 1/4, and in all these cases (which also would harm my web browsing security), the UAC dialog continued to interfere, so I reset it to 4/4, since that's obviously not the way to get rid of it in my use case (= sending harmless comspec commands from AHK to my system); I probably would have got rid of it if I did the setting to 0/4, which would have left me without any security to third-party attackers.
Thus, what can I do in order for the command window to accept and process my AHK commands, but without my system stopping the processing by displaying the UAC dialog?
(I could make manual changes to the registry if necessary.)

EDITS:
Thank you, harrymc. In fact, after several hours of trying, I hadn't seen this - new - error of mine at all (this line was correct first, then I got it wrong somehow); in my trial script, outcommented, I had previous tries for that with the correct syntax though, which did not work; now that one works indeed; I don't know why this is not persistent.
Also, this trial script is just some (working) lines (the other ones being out-commented), and this simple thing, now, even works from there, without the script being elevated.

Thank you, user3419297. As said above in my edit, for the simple task, this is not even needed, but this scriptlet works fine, I now have to answer the UAC dialog upon loading the AHK script, but can live with that.
Unfortunately, my real task does not work, even now, the command window remains empty, the command is not put into it, so is not processed there.
My real problem is Everything search, by command line, so one of these should work, but NONE of them do, in the amended, elevated script, variant 2 would be the correct syntax I think:
+^F2::
msgbox, variant 1: ; *
runwait, %comspec% "c:\Program Files\Everything\ES\es.exe -h"
; send, {enter}
msgbox, variant 2:
runwait, %comspec% "c:\Program Files\Everything\ES\es.exe" -h
; send, {enter}
msgbox, variant 3:
runwait, %comspec% "c:\Program Files\Everything\ES\es.exe" "-h"
; send, {enter}
msgbox, variant 4:
runwait, %comspec% ""c:\Program Files\Everything\ES\es.exe" -h"
; send, {enter}
msgbox, variant 5:
runwait, %comspec% ""c:\Program Files\Everything\ES\es.exe" "-h""
; send, {enter}
return

(* = BTW, variant 1 should bring an error message for the space in "Program Files", but since the command is not even written into the command window, even the mandatory error message will not appear.)
(The additional {enter}" commands are certainly not necessary, but with or without, the command text of the "runwait" (or "run") command is NOT written into the command window; all this, as said, sent from my now elevated main AHK script.)
It goes without saying that if I put the command
"c:\Program Files\Everything\ES\es.exe" -h
directly into a (non-elevated) command window (and then press Enter, of course), the Everything help is displayed in the command window.
Of course, the problem is now considerably complicated, since for checking out, you would have installed the Everything command line ("es.") exe, or possibly some other program.
Before saying it comes down to an Everything / es.exe problem ( https://www.voidtools.com/forum/viewtopic.php?t=1745 and https://www.voidtools.com/forum/viewtopic.php?t=7518 ) I would pretend that the command line should at least be written into the command window, with possible problems afterward, but as said, the command itself does not appear within the command window.
And, even from a non-elevated (extra) script, all this worked fine, incl. real searches, just days ago. (And I had no Everything update in-between, but possibly an AHK update (I did do that recently and may not have done es.exe searches afterwards indeed before today), and possible W10 updates anyway.)

SECOND EDIT
It does NOT seem to be a UAC problem, it all works identically from my now elevated main AHK script, and from any other, seemingly non-elevated script.
It seems it is NOT possible currently to execute a persistent command window from AHK, hence the impossibility to run even "simple" commands in such a window from AHK, without the /c attribute, hence the impossibility to display even the es.exe help there. See:
runwait, %comspec% /c dir c:\ >>d:\downloads\000.txt, , min ; works fine, but

runwait, %comspec% dir c:\ >>d:\downloads\0000.txt, , min ; does NOT work

On the other hand, even the slightest syntax error in es.exe OR in AHK will leave the command window empty, but see:
; the data to be retrieved is always identical:
progvar := "c:\program files\everything\ES\es.exe"
attrvar := "c: parents:1 -export-txt d:\downloads\0both.txt"

; no var used here, works:
; runwait, %comspec% /c "c:\program files\everything\ES\es.exe" c: parents:1 -export-txt d:\downloads\0none.txt

; ditto with persistent command window, command is NOT written into command window, so NO output either:
; runwait, %comspec% "c:\program files\everything\ES\es.exe" c: parents:1 -export-txt d:\downloads\0nonebutpersistent.txt

; only progvar used here, works:
; runwait, %comspec% /c "%progvar%" c: parents:1 -export-txt d:\downloads\0progonly.txt

; both vars used here, works:
runwait, %comspec% /c "%progvar%" %attrvar%

; ditto with persistent command window, command window (persistent) remains empty again:
; runwait, %comspec% "%progvar%" %attrvar%

return

It's obvious the missing functionality of AHK commands in a persistent command window will regularly mislead users since it (here: falsely) appears as "natural" to try out new commands in a persistent, "viewable" command window first, with then only when they work there, having them processed within a non-persistent window, with the /c attribute: Who could guess this "natural" way of doing things was a fallacy with AHK?

THIRD EDIT:
I can confirm that it's NOT a UAC problem, since for other reasons (additional tools didn't work anymore as expected with my AHK script elevated), I out-commented the additional script part again, and (after reboot) the indicated commands above continue to work.
(It goes without saying that putting the prog-calling part into a variable, whilst not doing so for the attributes part, wouldn't make sense, whilst the other way round would make sense; I put both parts into variables.)
For further processing, piping the output into the clipboard would be preferable, in most cases:
progvar := "c:\program files\everything\ES\es.exe"
attrvar := "c: parents:1 |clip"
runwait, %comspec% /c "%progvar%" %attrvar%

Answer: I think the problem is that the output file is badly specified.
Instead of d:downloads\000.txt you should have d:\downloads\000.txt.
Your formulation may fail if the current folder on D: is not the root.


How to access user account fields?

Question: When I look at $user like this
global $user
dpm($user);

I do not see the user account fields I added. How can I access them?
Answer: You need to use:
$account = user_load($user->uid);

Then, dump the $account object and you will see profile field.
Answer: The global variable $user doesn't contain all the properties you would find in a user object; in particular, it doesn't contain the fields associated with the user entity. If you need the complete user object, you need to use the following code.
$account = user_uid_optional_load();

Without any argument, user_uid_optional_load() returns the user object loaded from the database for the currently logged in user. If you have a user ID (e.g. you don't need the user object for the currently logged in user, but the user ID is passed to your function as parameter), then it is better to use the following code.
$account = user_load($uid);

How to access user account fields?


What is the role of Key Grips and Best Boys in nearly every movie?

Question: I have noticed there are always these two roles mentioned in the final credits of every movie. What do these people do?
Answer: Key Grip

In North American filmmaking, the key grip supervises all grip (lighting and rigging) crews and reports to the director of photography.
Before filming begins, the key grip attends location scouts and meets the director of photography to determine what additional tools (location-specific motor vehicles, dollies, cranes, mounts, etc.) will be needed, orders and prepares required equipment, and transports equipment to the filming location. Once on set, the key grip coordinates with the electric and camera departments alongside the director of photography to control lighting and camera movement and setup. As a supervisor, the key grip directs the crew of grips, many with specialized skills such as dolly grips, crane operators, or special equipment operators.

Best Boy

In a film crew there are two kinds of best boy: best boy electric and best boy grip. They are assistants to their department heads, the gaffer (in charge of electricals) and the key grip (lighting and rigging), respectively. In short, the best boy acts as the foreman for the department. A woman who performs the duties of a best boy may be called best girl. All are sometimes called best person.
Best boys are responsible for the day-to-day operation of the lighting or grip department. Their many responsibilities include the hiring, scheduling, and management of crew; the renting, ordering, inventory, and returning of equipment; workplace safety and maintaining discipline within their department; completing timecards and other paperwork; stocking of expendables; loading and unloading production trucks; planning and implementing the lighting or rigging of locations and/or sound stages; coordinating with rigging crews and additional photography units (if applicable); handling relations with the other production departments; overseeing the application of union rules (where relevant); and serving as the day-to-day representative of the department with the unit production manager and coordinator of their department.
Comment: There might be some confusion about gaffers and grips. Gaffers are in charge of the electricals for the lighting, but they also determine where lighting goes and how it works, along with the director, DP, cinematographer, and/or other crew depending on how the team works. A gaffer is a lighting tech, not merely an electrician. A grip is fundamentally someone who carries or moves things. The key grip is the head of all the grips. To me it seems like the key grip quote here doesn't make it so clear what grips do, and the parenthesis after gaffer doesn't explain that gaffers work on lights.


What happens to the data distribution and results if we calculate z-score of a z-scored data?

Question: The data that I am using is already z-scored and batch normalized. I accidentally calculated the z-score again and then performed further analysis and calculated results. Does it make sense to take z-score of a z-scored data distribution? Does it affect the distribution and the results? Thank you
Answer: Pretty much nothing happens. The mean of your z-score data is $0$, and the standard deviation is $1$. Thus, when you run your points through the formula, you subtract $0$ and then divide by $1$.
$$
z=\dfrac{x-\bar x}{s}
$$
Because you're likely doing this on a computer, it is possible that your $\bar x = 0$ and $s=1$ are stored as something like $0.0000000710008$ and $1.00000004000502203$. I would ignore that in every situation that comes to mind. Because you did something unusual, however, my recommendation is to redo your work with only the one z-score calculated, knowing that almost nothing is going to change. (You are setting yourself up for criticism that you can avoid.)
A simulation in R shows all $1000$ second z-scores to be within about $10^{-16} = 0.0000000000000001$ of the first z-scores. Since I simulated an exponential distribution, this fact does not depend on the data being normal.
set.seed(2021)
N <- 1000
z_score <- function(x){
  return((x - mean(x))/sd(x))
}
x <- rexp(N)
z <- z_score(x) # Calculate the z-scores
z2 <- z_score(z) # Calculate the z-scores of the z-scores.
summary(z - z2)
     Min.   1st Qu.    Median      Mean   3rd Qu.      Max.
0.000e+00 9.368e-17 1.110e-16 9.113e-17 1.110e-16 1.110e-16


What's the difference between "equery depends" and "equery depgraph"?

Question: xi@localhost /usr/src $ equery depgraph gcc | wc -l
872
xi@localhost /usr/src $ equery depends gcc
 * These packages depend on gcc:
app-admin/eselect-python-20100321 (>=sys-devel/gcc-3.4)
sys-devel/llvm-3.0-r2 (>=sys-devel/gcc-3.0)
sys-libs/glibc-2.15-r3 (>=sys-devel/gcc-3.4.4)
                       (arm ? >=sys-devel/gcc-4.1.0)
                       (x86 ? >=sys-devel/gcc-4.3)
                       (amd64 ? >=sys-devel/gcc-4.3)
                       (ppc ? >=sys-devel/gcc-4.1.0)
                       (ppc64 ? >=sys-devel/gcc-4.1.0)
xi@localhost /usr/src $ equery depgraph
Display a direct dependency graph for a given package

xi@localhost /usr/src $ equery depends
List all packages that depend on a atom given query

Comment: "depends" - those 2 packages depend on gcc? How few!
Comment: What are direct dependencies? What are indirect dependencies? Direct of gcc - those which depend on gcc (to be dependent - is to require gcc). Indirect of gcc = gcc are dependent of those packages? That is all the difference?
Comment: how to undertand directly and what's the difference . Depgraph indirect - there is a separate option. So it is not strict the difference. May be it's better to say in what purpose do they serve?
Comment: How they are usually used, in what context of thought and mind. This is my first experience with linux I use emerge to install and emerge --unmerge to uninstall. +may be some USE flags USE="" emerge, that's all. I've read a lot. But I don't know the way of thought in general.
Answer: equery depgraph <atom> will list you a graph of the dependencies  needs to be installed
equery depend <atom> lists all packages that directly need  to be installed.
Answer: equery depgraph <atom> outputs all the required dependencies for atom.
Use case: pre-install considerations

Where is software based on
Is it worth the extra amount of packages?
Prevent a whole tree of additional dependencies by USE flag tuning

Example: qt and kde libraries can  be pulled in while you are gnome user. You may be able to prevent it by disabling qt and kde USE flags. Or choose to find an alternative package offerings a similar solution.
equery depends <atom> gives reversed dependency resolution. So what other packages are pulled in by atom.
Use case: blocked packages
An installed package can prevent an update.

What other packages pulled this atom in?
Is it an absolute requirement or can we get rid of it by disabling an USE flag?
Consider if we need the package asking for this atom or if we really want to update.

Some more use cases for both commands:

portage tree dependency bug hunting
System cleanup


How to select login user with keyboard?

Question: I have a 4K monitor and before I have logged in, the mouse moves really slowly on the user login screen.  Once logged in, I have configured the Tracking speed in the Mouse System Preferences to move fast.  Since there is no known way to configure the default Tracking Speed before I've logged in, is there a way to select a login user without clicking on the user and using the keyboard to select a login?
Answer: You should be able to choose any of the login users either with an arbitrary arrow key (if the user name is somewhere in the middle more than one hit is necessary) & enter or by entering the first letter of the user name (or the first two if you have several names starting with the same letter) & enter.
Then enter the password.

How to select login user with keyboard?


Should Document library versioning be enabled when storing XML files?

Question: Should Document library versioning be enabled when storing XML files? I know the advantages of turning it on for MS office documents. Does it do any good turning it on for XML files and folders?
Answer: The benefits of versioning are the same no matter what type of file it is.  You should use versioning when:

The contents of the document are going to change, and
You want to be able to have access to previous versions of the document, for whatever reason (to see what changed, restore to a previous version if the current version is no longer valid, etc.)
Answer: You can always get the benefits of versioning in SharePoint whether you are adding versioning on word documents or on XML files.
When to enable:
So whenever your file contents or its metadata going to be changed and you want to see the changes made or restore the previous version then you should enable versioning.
Benefits:

Ability to audit the history of an item:
Version history allows you to retrace the history of an item or a document, since the date and time it was first created till present.
Ability to track metadata changes:
Any metadata changes are perfectly visible in the version history log.
Ability to track content changes:
If you enable versioning on a document library, you can access any previous versions of the document just by clicking on a previous version link.
Ability to restore previous versions:
You can also restore older versions if need be.
Ability to compare SharePoint versions:
This is not necessarily a SharePoint feature, but more of a Word feature. Essentially what you can do is compare different SharePoint versions of the document in Word using MS Word Compare feature.


Travel from Ohare Airport to Delevan WI

Question: Can I arrange an Uber directly from O'Hare airport ?   If so where do they generally pickup from?
Answer: Yes:

For most requests, you'll meet your driver upstairs on the Departures level.
Riders requesting Uber Black or SUV, and those in the International Terminal, please meet your driver downstairs on the Arrivals level.

The app will ask you for your location within the airport and will prompt you where to go when you do this.
Keep in mind that this is a considerable distance and will likely cost $100+. You might find it cheaper to get a car service or shuttle, rent a car, take the train part of the way, or use other transport options.

Travel from Ohare Airport to Delevan WI


Is a batsman out when any of his things slip away and hit the stumps?

Question: Is a batsman out if his helmet, bat or any of his equipment slip away from him and hit the stumps?It always confuses me
Answer: Yes, it would be out hit wicket under Law 35.1 (a). Law 28.1 indicates that the wicket can be put down by the ball, the bat, any part of the bat becoming detached, the striker's person, or "any part of his clothing or equipment becoming detached."
Comment: @msh210 http://sports.stackexchange.com/questions/11908/what-if-an-opposing-player-uses-part-of-the-batsmans-clothing-to-put-down-the-w
Comment: What if a batsman puts his helmet behind the stumps, while a spinner is bowling and an opposing player uses it to knock off the bails?
Answer: The answer from Spinner, noting that "any part of his clothing or equipment" can cause a dismissal by Hit Wicket, is correct. I would just like to add a few examples of things that have actually fallen onto the batsman's wicket, causing the batsman to be out Hit Wicket.

A dropped bat. This happened to Kumar Sangakkara in a match against India in 2009.
A helmet. This has happened to Adam Parore after being hit by a short ball from Brett Lee, and to Kevin Pietersen, similarly dismissed by Dwayne Bravo
A cap. A gust of wind blew the cap of Warwickshire's MJK Smith at Edgebaston onto his own wicket.
A glove. This happened to Alf Revill in 1953

I searched for "Hit Wicket shoe" and "Hit wicket Toupee", but couldn't find any reports, but they would of course also be covered by "any part of his clothing or equipment".
Comment: what if? http://sports.stackexchange.com/questions/11908/what-if-an-opposing-player-uses-part-of-the-batsmans-clothing-to-put-down-the-w
Comment: Regular TMS listeners will of course be wondering what the law is for a detached beard.


Problems with xlr mic

Question: So for about 2 months now i've owned a Audiotechnica  AT2020, which has been working fine for the whole time i've owned it. It is hooked up to a Newer NW-100 power supply, and uses an xlr cable to get power to the mic, and a XLR to USB to help with getting the mic to work with my PC. Recently, i've been having an issue where the mic becomes really low in sound and my friends can hardly hear me. I have to move it and do other things before it works, but today it just started not working flat. I have to yell to even get any sort of sound out of it. Would love some help here, thank you.
Comment: Test with another phantom power source. Test other cables.
Comment: I'm voting to close this question as off-topic because it is not about sound design, but electrical/electronic diagnosis.
Answer: As Tetsujin commented, you should test it with a different phantom power source and different cable to identify where the problem is. I'm rather doubtful it's the cable but I would test it anyway. Do make sure that you check it isn't a gain knob turned down, a pad button pressed or a dynamic processor (compressor etc.) on the channel.
Most likely, your power supply is failing. If you have a multimeter handy, you could test it to make sure it gives 48V (48V is the standard voltage for phantom power but do check the spec sheet of your power supply because I think some manufacturers can use as low as 5V).
If it doesn't, you can either get a new one or repair it. Repair-wise, I would change all the electrolytic capacitors and check the voltage regulator(s).
If it isn't the cable or power supply, I would open the microphone very carefully and give it a cleaning with a soft brush. Take pictures of the process to make sure you don't have any bits left when you put it back together. Although I've never looked into the electronics inside a microphone, I would have a look for obviously damaged components. Hopefully, it will be something you can spot with a naked eye.
P.S. I forgot to mention: do none of the above if your equipment is within warranty.

Problems with xlr mic


A combinatorial identity with Pochhammer's symbol

Question: Let $m,k$ be an positive integers with $k\le m$. I am trying to prove $$\sum_{j=0}^k{\frac{1}{2}\choose k-j}\frac{2^{2j}(m+j)!}{(m-j)!(2j)!}=\frac{P(n,k)}{(2k)!}$$
where $n=2m+1$ and $P(n,k)=\prod_{i=0}^{k-1} (n^2-(2i)^2)$. We can use Pochhammer's symbol and write the left side as
$$(-1)^k\sum_{j=0}^k\frac{(-1/2)_{k-j}(m+1)_j(-m)_j}{(1/2)_j(k-j)!j!}$$
We can also write the right hand side as $$(-1)^k\frac{(-m-\frac{1}{2})_k(m+\frac{1}{2})_k}{(\frac{1}{2})_kk!}.$$ So I think the identity must follow from some identities in hypergeometric functions.  Does anyone see a way to do it?
Comment: Note: Recently duplicated [on MathOverflow](http://mathoverflow.net/questions/129792) and treated there.
Answer: Treating both sides as coefficients of $x^k$ in a power series with variable $x$, the left-hand side turns into a power-series product, one factor representing $\sqrt{1-x}$. We end up with a special case of the known hypergeometric identity
$$(1-x)^{a+b-c} {}_2F_1(a,b;c;x) = {}_2F_1(c-a,c-b;c;x)$$
with $a = m+1$, $b = -m$, $c = 1/2$.
Cf. (34) of this MathWorld entry.
Comment: This formula can be found in: Abramowitz, M. and Stegun, I. A. (Eds.). "Hypergeometric Functions." Ch. 15 inHandbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables, 9th printing. New York: Dover, pp. 555-566, 1972. The formula is 15.3.3 on page 559.


What do you call the act of two separate teams within an organization meeting together to increase cooperation?

Question: Is there a word like that that can be used to describe such an action, event? I used to work at a software firm where there were a lot of separate teams and they would sometimes work together for a big project and before that we would meet up to know each other.
Answer: You could call this event confluence:

a coming together of people or things; concourse.

From vocabulary.com:

Confluence means a flowing together. In a literal sense, it's about rivers. But it's more often used to talk about the coming together of factors or ideas, or of cultures in a diverse city.
Comment: I have seen "Confluence" mostly in its original, literal meaning: the joining of two rivers. Metaphorically, it is most often used for things that can be thought of as streams or flows. It would seem odd to use it for teams of people, to me.
Comment: @DavidSiegel I think you're right about this. I see this used a lot in the context of ideas or culture, so I assumed it was fine to ignore the flow connotation. I didn't consider that ideas or culture could be seen as a flow.
Answer: I work in a company not unlike the one you describe, and meetings where groups get together at the start of a project or a period of joint work are often called "kick-off" meetings, because they start the project, whatever it is. (A sports analogy.) Sometimes they are just called "introductory"  or "getting-to-know-you" meetings. Not very eloquent terms, but they are pretty clear.


Inject javascript into a page from a feature

Question: I want to add a verb (link in the top left menu of a web part) to all the web parts in Sharepoint 2010. Is there a way to inject javascript into a all the pages from a custom feature?
Answer: You can write a custom control that uses the SharePoint scriptlink control and furthers registers your JS file using the ScriptLink.Register method on the page.
Next you can deploy this custom control as a delegate control. You can use any existing delegate control like AdditionalPageHead inside the master page or create a new one.
Answer: somehow injecting javascript into all the pages just sounds like a bad idea, you could however alter the master page to include a javascript file and deploy the updated master page as part of the feature.
Comment: This sounds good, but what if the user has customized his master page already? I will overwrite it.
Answer: Do you really need to add your action as a webpart verb?
Is Ribbon UI or a Site Action acceptable?
How to: Modify the User Interface Using Custom Actions
This series of articles goes into more depth.
Customizing Ribbon UI - Part 1
Comment: This new verb will perform and action based on the content of the web part. So, I need a way to know which web part the user wants to perform this action on. I think I can use a ribbon button or site action as long as there is a way of knowing the specific web part.
Comment: Ribbon UI can interact with the currently selected webpart.


Charge and discharge LiPo batteries with BMS 3S

Question: I am looking for a solution to power a Raspberry Pi connected to a LCD screen 10 inch with three LiPo batteries 3.7V 5000mAh connected to two BMS 3S for charge and discharge. I designed the following circuit but I have doubts on its correctness. In case this is correct what is the expected battery life in hours?
Comment: Does the BMS manual really say that you can connect them in parallel?
Comment: hello, currently I don't found this information in the BMS data sheet.
Answer: Without the manual for the BMS it is hard to give an authoritative response, but I really don't think that you can connect these devices in parallel.
A BMS typically want "single access" to the batteries in question to control current and/or voltage. One BMS does not know how much current to add to the flow if there is another one which it has no control over.
It could work if there was a secondary communication of some sort between the boards, but it appears to lack such a feature.
Answer:
In case this is correct which is the battery life in hours?

Your battery has MAX 63WH, your load is 7.5WH, so roughly 7.5 hours max runtime. You also have to factor-in efficiency losses, 10~15% and LiPo cycle health.
LiPo battery life cycle drops significantly when discharging them all the way down to 0% capacity. It's better to leave at least 30% in them, then recharge. Also they are not happy sitting full charged (4.20v per/cell), this also kills the life of the battery. Take these two factors in account for life cycle longevity.
Regarding the BMS question, the other posters are correct in "they/we" don't know for sure if they are OK with paralleling them, seek the answer to that or seek another single BMS that will do the job.


How to solve the overlap between a rectangle and a circle that collide

Question: I have two figures - a circle and a rectangle and i have a method that checks whether the two figures collide. How to prevent them  from overlapping during collision?
Comment: Check whether they are _going_ to collide instead of if they _are_ colliding maybe.
Comment: If you are able to check if they are colliding/overlapping, you should be able to calculate by how much. If you are doing a reactive collision, then you should shift either the circle or the rectangle away by that calculated amount.
Comment: Very important: is this physically accurate motion, or is it kinematic motion (i.e. controlled purely by player input, without momentum etc.)? -- This impacts on the answer in several ways.
Answer: One solution would be to use raycasting collision for the circles, and traditional box-collisions for rect-rect collisions.
Answer: if the speed of the objects is constant (or you can predict it accurately) you can check if they are going to collide, if yes don't move object (or move them so they touch side to side)
one other thing you can do is save previous location, calculate object's new location, if objects collide, move to previous location


Arduino components

Question: I'm teaching and learning coding with MicroBit and was wondering if these components are compatible with MicroBit. The specific kits labeled for MicroBit are twice the price but the components look similar. Just trying to save a few bucks. Would this kit work with my MicroBit?
Comment: That is a whole collection of components, most of them simple electronic components not specific for Arduino. Some components are more complex, but they also should work with the microbit. This is seen from the first glance, I didn't looked into everything in detail. What can be done simultaneously on the microbit depends more on what you try to build. What components did you see, that where marked compatible with Microbit? It might be easier to point out devices, that are microbit specific instead of the one which are not.
Answer: It looks like the MicroBit runs on 3.3V versus 5V for most Arduino boards. You'd need to use 3.3V components.
It looks like the kit you linked to is built for (and includes) a 5V Arduino, so those accessories would not work with your MicroBit.
There are other Arduino boards that run on 3.3V. Look for 3.3v accessories. Those should work.
EDIT:

I assume that the MicroBit is capable of I2C interfacing. If so, you should look at the SparkFun Qwiic system. It's a setup with 3.3V I2C serial interface in a 4-wire ribbon cable with a standard connector. You can easily daisy-chain Qwiic devices by just plugging Qwiic cables between them, and they are reasonably priced. I bought some of them thinking I could use them with my Arduino projects, only to discover that they use 3.3V, so I can't use them without I2C voltage translation interfaces, which makes them much less appealing.
Comment: Thanks. For speedy response
Comment: See the edit to my answer, talking about SparkFun Qwicc devices.

Arduino components


Consider synonymizing [technique] and [skills]

Question: All of the skills questions could reasonably be retagged under the tag guidance for technique, with the possible exception of one about group-rides.
Comment: Isn't [skills] just a meta-tag which should be deleted?  It doesn't seem to be able to stand alone on a question.
Comment: @Chenmunka Reasonable question. Could one say the same of [technique]? Feel free to add "Just remove it" as an answer with your justification.
Answer: I would suggest that skills is a meta-tag.  It cannot stand as the only tag on any question as it is too vague in itself.
It seems to be a prime candidate for the burnination process rather than synonimize it with anything.
Comment: This is actually a good point.  There are probably useful tags _within_ [skills], but the tag itself is too broad to be very useful.  We could probably usefully split out something like [riding-skills], but that would be a manually curated process.  (We'd also want to decide we don't want to call it [riding-techniques].)  Are there enough skills specific to the sub-discipline to have a [mtb-skills]?


huge size of debug.log file in Magento2

Question: I have created a cronjob which will create or update a number of products(around 2000 products, runs cron two times in a day). When the cron runs and update the products data, huge amount of "cache-invalidated" logs are written to debug.log file which largely increases the size of the debug.log. My system is in production mode. How can we block the system generated "cache-invalidated" logs.
Answer: It is an bug in magento 2.0 -2.1 version.
You need to upgrade your system to 2.2 version than issue will be resolve.
I have face same problem and for resolve this issue, i have run a cron job which is deleted that file 5 min interval.

huge size of debug.log file in Magento2


Is there any book on the philosophical implications of Theoretical Computer Science?

Question: I find some books about computers, but all of them are about technology. I want something more linked to theory.
Comment: [Gödel, Escher, Bach](https://en.wikipedia.org/wiki/G%C3%B6del,_Escher,_Bach) comes to mind, but I'm not sure whether that's the kind of stuff you're looking for.
Comment: Is [Impagliazzo's Five Worlds](https://www.researchgate.net/publication/3653458_Personal_view_of_average-case_complexity) the kind of thing you're looking for?
Answer: Try the 50+ page essay "Why Philosophers Should Care About Computational Complexity" https://arxiv.org/abs/1108.1791
Comment: It's apparently not on that essay, but Aaronson tends to quip that [computer science should be called quantitative epistemology](https://www.scottaaronson.com/democritus/lec13.html), which brings it closer to philosophical grounds.
Answer: Quantum Computing Since Democritus by Scott Aaronson is the closest match I can think of. I don't think there is a single book completely devoted to philosophical implications of TCS.
Answer: Opening and doing a quick search in the (classic) Computational Complexity book of Arora and Barak (online draft here), there are 19 occurrences of the word "philosophical", including such subsections as

"On the philosophical importance of $\mathrm{P}$"
"The philosophical importance of $\mathrm{NP}$"
a discussion of randomness in Chapter 16 ("Derandomization, Expanders and Extractors").
Answer: To complement some of the above answers, Avi Widgerson's recent book Mathematics and Computation briefly discusses philosophical interplays between computer science and philosophy in section 20.5. More broadly, the entire book contains a lot of material of philosophical interest, as it focuses mainly on the interplay between seemingly different fields, and does so by explaining the underlying structure and meaning of various concepts of ToC (randomness, knowledge, interaction, evolution, induction, learning... Among many others). While not a book about philosophy in itself, it makes the reader wonder about the new light shed by ToC on all these concepts. And it significantly departs from standard schoolbooks (indeed, that's not what this book is), as it contains no proofs. I highly recommend it.
Answer: Here is another essay of a philosophical nature by Scott Aaronson. The Ghost in the Quantum Turing Machine
Answer: John Searle in his book "The Rediscovery of the Mind" among other things raises the question what a computation is. In particular he states that "being computational" is not a property inherent to any process. Rather, there must be some observer attributing the "meaning" to the process.
This influential hypothesis has created quite some literature though mostly in the form of articles, not books, I think.
Answer: Avi Wigderson, in Knowledge, Creativity and P versus NP, argues that the philosophical question: Can creativity be automated? is equivalent to P = NP?.
Answer: The Philosophy of Computer Science, in the Stanford Encyclopedia of Philosophy: https://plato.stanford.edu/entries/computer-science/ with an interesting bibliography.
Answer: I highly recommend Pudlak's Logical Foundations of Mathematics and Computational Complexity.
Answer: As far as I know, there is no book dedicated exclusively to philosophical implications of theoretical computer science. However, there is some philosophical work done around complexity theory and related topics, mostly in the context of philosophy of mathematics. That is, more about philosophical applications. Keep in mind that, due to the way theoretical computer science has historically developed (in computer science departments rather than in math of logic departments), philosophers have not paid much attention to it and have instead remained on the more mathematical logic side of things. As a result, the existing literature is scattered and not necessarily linked so precise results.
Nevertheless, the following are some pointers that come to mind (on top of the ones other users have suggested):

Walter Dean, who is perhaps the contemporary analytic philosopher who was written the most about this, has a nice survey about computational complexity published on Philosophia Mathematica, but this is more for philosophers who don't know about complexity theory

Dean is also the author of the Standford Encyclopedia of Philosophy entry on this same topic. Section 4 contains references to some nice philosophical considerations.

The main philosophical connection between philosophy of mathematics and complexity theory is perhaps through issues related to ultrafinitism and proof complexity. Dean's SEP entry above outlines some of this, but if you want to go into more detail, the following might be relevant:

Dean's paper on how computational complexity brings light into the sorites paradox

I have myself written about this in the past. This is from a 2020 unpublished manuscript of mine on the relation between complexity theory, philosophy of mathematics and strict finitism.

In another unpublished manuscript of mine, amongst other things, I make some unorthodox philosophical remarks on the quest for faster matrix multiplication algorithms in the context of the philosophy of mathematical practice (see Section 3.2).

Thomas Tymoczko's New Directions in the Philosophy of Mathematics is a volume of collected works on alternative approaches to the philosophy of mathematics, some of which are inspired by issues involving tractability and computers. All of the essays there are really interesting, but in particular the ones by Lipton and Chaitin might the closest ones to TCS topics.

In a less analytic tradition (though not strictly continental, in case you are allergic to that), and also concerned with issues of strict finitism, computational complexity can be hinted at in some works by philosopher Brian Rotman. In particular, his books Ad Infinitum and Mathematics as Sign might be of interest.

Another area where computational complexity comes up sometimes is cognitive science. Two pointers come to mind:

This article by Pantsar connecting tractability and descriptive complexity to cognition.

This other paper by Patricia Rich, Ronald de Haan, Todd Wareham and Iris van Rooij suggested looking at computational complexity and parameterized complexity in cognitive science. This in particular addresses the common concern some of us have that computational complexity is too idealistic and precise to be used to model real-world phenomena.

Hope this helps a bit!
Answer: I haven't done much reading myself but i find the book "Structure and Interpretation of Computer Programs" very eye opening.
Gerry Sussman has done an amazing work with that book.
It's worth a read. :-)
Full Book Here
Answer: lance fortnow "the golden ticket" , it deals with the consequences of what happens in case P=NP and other issues in a very lighter manner.


Numbering subsubsections in Lyx

Question: I need to number subsubsections i used in my Lyx document. I have tried to use the unnumbered subsubsection and the numbered default one, but it is does not matter whhich one i select . It is always unnumbered anyway.
Comment: [Welcome to TeX.sx!](http://goo.gl/z69vm) Your post was migrated here from [so]. Please register on this site, too, and make sure that both accounts are associated with each other (by using the same OpenID), otherwise you won't be able to comment on or accept answers or edit your question.
Answer: Generally you can go to "Document > Settings... > Numbering & TOC" and slide those sliders to the position you need. The table below shows the expected result of the sliders.
This may depend on your chosen document class and style. If it still doesn't work, you should provide the class/style/template.

Numbering subsubsections in Lyx


Should I train all combat skills a bit or just one skill a lot?

Question: I've been training magic a lot on RS 3 lately reaching level 22 while my normal attack and strength are at level 4 and ranged is even at level 1. Is this normal? or should I be training all of these skills to around the same level?
Answer: Leveling up your skills tied to combat will increase your overall combat level a detailed description on what this does and the benefits can be found here
But for the sake of ease I will highlight the important bits here
which skills and the formula used to calculate the combat level:

Attack and Strength or Ranged or Magic
Defence
Constitution
Prayer
Summoning (not applied toward combat level in free worlds)

The effect of your combat level:

Normally, aggressive NPC's will stop attacking a player if the player
  has  double the NPC's combat level +1. There are exceptions, however -
  for  example, some monsters in the Wilderness that are normally not
  aggressive will be aggressive to players no matter what their combat
  level is. Also, normally aggressive monsters that are level 69 or
  above will always attack a player, since the maximum combat level for
  players is 138.

So to answer your question, no it is not needed if you want to but it can be recommended as it does help you.
Answer: I would suggest to take a look at this OSRS Combat Calc. As this tool will help you to determine what level for which combat level you need. So using this tool you can easily plan ahead on which combat level to lvl up first.
Answer: I will preface this answer with the assumption that you have a "main" combat skill which is the one you like the most and which your combat level is based on.  Defence, HP, Prayer, and Summoning help in various situations regardless of your preferred combat method and you definitely will want to train those (unless you are going for a pure account or want to have a low combat level for your main stats for PvP).
This depends on your goals when playing.  If you are only interested in fighting things and getting loot or PvP, then your non-main combat skills do not matter very much.  Melee can be useful when you run out of runes and ranged is good for certain enemy types and PvP strategies, but magic is already the most useful with teleport abilities, buffs, and enchantments.  Regardless, you will rarely if ever be forced to use a combat type other than your preferred one if you pick your battles.
If you just want to max out your combat level, the formula provided in KevinTheGreat's answer shows that it only uses the maximum level of your magic OR ranged OR attack/strength.  Therefore the other combat types don't matter whatsoever, though you will need to train Def, HP, Prayer, and Summoning.
If you want to explore all of the games quests, mini-games, and achievements however, you will need to have levels in every skill.  Desert Treasure requires 50 magic, Temple of Ikov needs 40 ranged, and Legends Quest demands 50 strength, and these aren't even the highest level quests!  A lot of this game is exploring the world and setting your own goals, so there's no there's no right answer to this question, but if you want to do and see everything, you gotta train every skill.


What would prevent two black holes from hitting speed of light in the flowing scenario?

Question: If two super massive black hole are 10 l.y away and completely still relative to one another... They will start moving towards each other due gravity but they will never reach each other due universal expansion, in this case they will accelerate for an infinite amount of time, what will prevent them from reaching the speed of light once they reach 99,999...%  light speed  (and still accelerating)?
Comment: If the expansion counteracts their attraction, they will not get any velocity at all.
Comment: Possible duplicates: https://physics.stackexchange.com/q/24319/2451 and links therein.
Answer: You are making a wrong assumption that the space expansion "pulls" matter apart with a force. It does not. When two heavy objects are attracted to each other with a gravitational force, it is the only force that acts on them. The space expansion does not apply a counteracting force. In other words, in the universe expanding without acceleration, the space expansion is manifested by the recession speed, but not by force or acceleration. Therefore, in your example, nothing would "pull apart" the black holes, other than their initial speed.
At a 10-ly distance, the recession speed due to the space expansion is approximately 2.4 cm/sec, not a significant amount. However, the gravitational acceleration of a black hole of 2 solar masses at this distance is 0.000,000,000,000,03 m/s^2. It would take approximately 25,000 years for the black holes to stop moving apart and start moving toward each other with no effect from the space expansion.
According to the recent data, our universe may be expanding with a small acceleration. In this case the scenario would be slightly different. However, the acceleration is so small, that it would not produce a significant effect. So the overall picture would remain the same.
You can find more details here: Why does space expansion not expand matter?


What are the storage and lodging capacities for the towns and cities in the game?

Question: I'm considering my options for a couple of towns to heavily invest contribution in. While I certainly have a slew of variables to consider, I'm trying to narrow things down a bit and a large consideration for me right now is lodging and storage space. What are the max lodging and storage capacity for the various towns in Black Desert Online? I'm only interested in large towns/cities. Random farms need not apply.
Comment: I can give you a great answer of how worker type and location should be "computed" if you choose to ask about it (with speed formulas etc, but answer is long and is not really related to the original question). Choosing investing by storage and lodging alone is not optimal.
Comment: @zozo That's not really a question that concerns me in particular because I'm not online enough to maximize the benefits of managing workers like that. But I'm sure someone somewhere on the internet would find it interesting.
Comment: say hello to Eilton
Answer: For storage, The largest city is Calpheon, this has the most building options, and is centrally located if you plan to stay on the "life side" of the map.
Another option, which most players seem to prefer, is Heidel. It is smaller than Calpheon (making it much easier to navigate), and still has plenty of options for building opportunities. Heidel is also more central to the entire map, making accessing every area a bit easier.
As for the lodging side of your question, you can have workers Live in Velia but still do work somewhere else entirely, it will just take a little bit longer. So again, Calpheon or Heidel will be your best option (there's no reason not to do both, it's cheaper contribution point investments that way anyway)
You can always permanently increase the storage/lodging units of cities with pearl/loyalty items as well.
Personally, I tend to stick around Calpheon more than Heidel, but that's because I do more work in Port Epheria nearby.
Comment: Then your best bet would be Calpheon, It has by far the most houses for storage and lodging, with many farm nodes nearby (the plantations) for workers. Velia also has great farm choices, but barely any space for buildings.
Comment: In regards to sending workers to any connected node regardless of where they are lodged, I agree. However, a factor there is that the worker will drop off what they produce in the city that are lodged in. One of my goals is to try to reduce how much traveling and/or shipping I have to do to centralize the assets being generated.
Answer: All the inventories are limited at 192 slots. And all major cities can get to that.
Regarding lodging the largest you could get is from Calpheon, followed by Heidel, Altinova and Valencia (didn't count the exact the number but they looked rather similar to me), while Velia is totally worker deprived (for Balenos area you need to use workers from both Olvia and Velia to properly cover it).
As a side note thought (not requested by the question but I think is really important), you should consider the CP investment for what you need, and what nodes you want to send your workers to. Heidel is popular because Heidel lodging is really cheap (1 cp / lodging, even less for some). Valencia and Grana for example are really expensive. Also Heidel is near center of the map so you can cover more ground with it. There are more things to consider when choosing investing options.
Answer: The four largest would be Veila, Heidel City, Calphaleon, and Altinova. If you are leveling quickly and hitting the desert soon, I recommend Altinova. If you are working on your life skills instead, any of the other three are fine.
Comment: So, this doesn't really answer my question. Of the towns you've listed, I'm asking what their max storage capacities are if I decide to commit the contribution points.


Proximity Sensor Browser Support

Question: I haven't tracked down any browsers that support proximity sensors. Is anybody aware of any browser that supports access to proximity sensors?
Answer: The only mobile browser I'm aware of with support for Proximity sensors will be the BB10 browser using WebWorks.  That said, the spec went into Last Call working draft status today (ends January 24).  Hopefully we'll see some support in Android soon.

Proximity Sensor Browser Support


What is the drift velocity of an electron in a superconductor?

Question: How is it,when compared to drift velocity in a conductor?
Comment: Related? [Relativistic drift velocity of electrons in a superconductor?](https://physics.stackexchange.com/q/36053/)
Answer: Drift velocity of electrons is a concept dependent on the solid state model assumed for a solid. Here is a microscopic view of current

Where drift velocity can be defined .
Even though conductors are best described with the band theory of solids, this microscopic view makes sense as charge moves in steps in the lattice dimensions.
For superconductivity, models exist where the behavior of electrons carrying the charge is not as the above picture.

BCS theory applies directly to superconductors such as Nb3Ge (Tc = 23K) in which the electrons are bound together by their interaction with the vibrations of the underlying lattice: one electron in the pair polarizes the lattice by attracting the nuclei towards it, leaving a region of excess positive charge (a potential well) into which a second electron is attracted - the positively charged nuclei thus mediate an attraction between the negatively charged electrons. Only electrons within the vibrational frequency of Ef can be paired by this interaction, and so only a small fraction of the electrons become superconducting.

I suppose that for the not bonded electrons, if a field is applied the drift velocity will be the one defined at the top. Otherwise a specific model is needed for the drift velocity of charge carriers in a superconducting circuit. Note that Ohms law does not apply as the resistance is zero, and an applied electric field will destroy superconductivity.
This paper uses the drift velocity of charge carriers in a superconductor in a specific model.
This measurement states :

The
  drift
  velocity,
  in
  agreement
  with
  the
  theory,
  turned
  out
  to
  be
  proportional
  to
  the
  current
  density
  and
  independent
  of
  the
  configuration
  of
  the
  normal
  and
  superconducting
  layer.

Thus the drift velocity is the one of the material, of course at the low temperatures of superconductivity. There exists a temperature dependence :

This is for a semiconductor, Gemanium, but a7 slight dependence exists also in metals as far as I can check.
Comment: So, short answer is about 10Km/s which is a huge difference with the few microns per second we have in normal solid conductors.
Comment: Please summarise the paper which you linked or at least tell me what to read. I am just starting to study superconductors.
Comment: you should read the linked paper, it is simple enough  https://arxiv.org/ftp/arxiv/papers/1012/1012.0879.pdf
Answer: Below I copied part of the Wiki article that explains drift veolcity.
The term σ refers to the conductivity which for a material in superconducting mode would be very large. Therefore it would seem that the drift velocity would be much higher than for ordinary conducting materials. The rest of the variables are of course important, but you did not specify the specific counductor material. Ordinary materials only drift at a less than a millimeter per second so even in a superconductor it would still be very much less than the speed of light.
From wiki:
In terms of the basic properties of the right-cylindrical current-carrying metallic ohmic conductor, where the charge-carriers are electrons, this expression can be rewritten as[citation needed]:
where,
u is again the drift velocity of the electrons, in m⋅s−1;
m is the molecular mass of the metal, in kg;
ΔV is the voltage applied across the conductor, in V;
ρ is the density (mass per unit volume) of the conductor, in kg⋅m−3;
e is the elementary charge, in C;
f is the number of free electrons per atom.
ℓ is the length of the conductor, in m; and
σ is the electric conductivity of the medium at the temperature considered, in S/m
drift velocities in superconducting materials were about the same as for good conductors like copper wire. So somewhere in the neighborhood of .1 to 1 mm/sec.


How do I extract the address from a scriptPubKey?

Question: I am creating a block parser and just learned about Scripts in Bitcoin yesterday which is kind of confusing so far. I want to extract the addresses involved in each transaction. Right now, I am able to read the script for each output. To extract the address, am I correct in thinking that my code will need to handle all of the different formats of scriptPubKeys?  Is there any sample code out there to guide me? If I am completely wrong, how should I do it?
Answer: Yes, to get addresses from scriptPubKeys, you will need to do a pattern match. There are only a small number of address types each with their own fixed scriptPubKey pattern. Keep in mind that not all scriptPubKeys map to an address so you will find scriptPubKeys that have no address and you will need to handle those.
Bitcoin Core has a pattern matcher for going from scriptPubKeys to address types in the solver function. The MatchPayToPubkey, MatchPayToPubkeyHash, and MatchMultisig can be found higher up in that file. The IsPayToScriptHash and IsWitnessProgram functions can be found here.
One thing to note about the solver is that it does not return just address types. Some of the types it returns do not map to addresses. These are TX_NULLDATA, TX_MULTISIG, TX_PUBKEY, and TX_NONSTANDARD.
It may also be useful for you to see how you get the scriptPubKey from an address. Bitcoin Core does it here.
Comment: Thanks a lot Andrew. I'm not great at C++ (only been programming for a year) but I think I can use it as a guide. One more question: why would a scriptPubKey not map to an address? For the purposes of my block parser, would I just discard it?
Comment: A scriptPubKey can be literally any sequence of bytes; it doesn't have to be a valid script, the output will just be unspendable. Those standard scriptPubKeys that don't have addresses occur because there was/is no reason for them to have addresses. A very common one that you will see are Pay to Pubkey outputs. These are in basically all of the early blocks because the original Bitcoin client created coinbase transactions with P2PK outputs. Some block explorers will convert these to addresses, but that is incorrect.
Comment: I recommend that you do not discard them because you will be losing information. It is useful to know exactly what the scriptPubKey for an output is. So you should still just store them. Maybe decode them into opcode notation instead of storing the bytes themselves, but you should still keep the scripts around in some form.
Comment: Regarding the handling of segwit txns, is my understanding correct?

1) Check if it's non-native or native.

2) If the former, check if it's p2sh-p2wpkh or p2sh-p2wsh and then handle it like any other p2sh.

3) If the latter, determine if it's p2wpkh or p2wsh.

4) After extracting the script hash, perform the appropriate hashing and base58check encoding to extract the addresses?
Comment: You won't be able to tell if an output is non-native segwit. The scriptPubKey will not contain the segwit script at all, you will just see a p2sh output. So you should treat all p2sh outputs the same, because, as outputs, they are.
Answer: With library https://github.com/petertodd/python-bitcoinlib
a P2WPKH address derivation example:
from bitcoin import SelectParams
from bitcoin.core import x
from bitcoin.core.script import CScript
from bitcoin.wallet import P2WPKHBitcoinAddress

SelectParams('mainnet')
# Create an address from that private key.
scriptPubKey = CScript(x('Paste_scriptPubKey_Here'))
address = P2WPKHBitcoinAddress.from_scriptPubKey(scriptPubKey)
print(address)


Rober Bresson's notes on sound

Question: http://filmsound.org/articles/bresson.htmw
Sight and Hearing
To know what business that sound (or that image) has there.
What is for the eye must not duplicate what is for the ear.
If the eye is entirely won, give nothing or almost nothing to the ear*. One can not be at
the same time all eye and all ear.
When a sound can replace an image, cut the image or neutralize it. The ear goes more toward the within, the eye toward the outer.
A sound must never come to the help of a image, nor an image to help the of sound.
If a sound is the obligatory complement of an image, give preponderance either to the sound or to the image. If equal, they damage or kill each other, as e say of colors
Image and sound must not support each other, but must work each in turn through a sort of relay.
The eye solicited alone makes the ear impatient, the ear solicited alone ,makes the eye impatient. Use these impatiences. Power of the cinematographer who appeals to the senses in governable way. Against the tactics of speed, of noise, set tactics of slowness, of silence
What is the forum's general consensus on these notes?  Have they been useful to you?  I have learned a lot from sound books and reading and re-reading old theory is fun and useful, I'm also hoping there is a new theory book that comes out of modern times.
Answer: These have been influential for me for a very long time... especially "Against the tactics of speed, of noise, set tactics of slowness, of silence"
re more recent film sound theory books, I can reccomend Michel Chions book Audio Vision

Rober Bresson's notes on sound


Why Frege thinks geometry is synthetic?

Question: Frege believes that arithmetic is analytical. Why not Frege thinks geometry can be reduced to arithmetic by coordinate system or something else?
Comment: Some references would help.
Comment: "*There is accordingly a noteworthy difference between geometry and arithmetic in the way in which their fundamental principles are grounded. The elements of all geometrical constructions are intuitions, and geometry refers to intuition as the source of its axioms. Since the object of arithmetic does not have an intuitive character, its fundamental propositions cannot stem from intuition…*", Frege, 1874, see [SEP](https://plato.stanford.edu/entries/frege/#FreLif). That one can build arithmetic models of geometry is moot, they are part not of geometry, but of arithmetic.
Comment: Spinoza used a geometric method to present his 'Ethics' and because there are so many interpretations of what precisely geometry consists in there are multiple interpretations of the origin and nature of geometry. Why it may be considered synthetic results from something I term, human geometry.  In my Book, 'To Discern Divinity", on page 35, you will find;  'On Human Geometry and the 'More Geometrica'. It can be downloaded at Academia.edu. The method of human walking and circumlocution daily, involves a barely perceptible gyroscopic sensitivity which guides us. This is the origin of synthetic.
Answer: In Frege's time, geometry had exploded as a discipline. Descartes' invention of the "Cartesian" coordinate system had been analytic, even founded analytic geometry, but over the centuries since then the nature of geometry had broadened vastly.
Leibnitz envisaged a "geometry of position" in which the relations between objects would be captured without any need for Cartesian numbers. Euler's polyhedron formula, concerning the numbers of corners, edges and faces of a polyhedron such as a cube, founded that discipline. In Frege's time, Poincaré greatly advanced it and it became known as topology, sometimes described as "rubber-sheet geometry".
Meanwhile Gauss among others had independently discovered non-Euclidean geometries, in which the angles of a triangle do not add up to 180 deg. Poincaré chipped in with his own ideas there, too. Euclid's axioms came under fire, with each geometry requiring its own set of axioms. These axioms involved things like points, lines and planes, and one thing meeting another. This mode of reasoning is known as synthetic, in contrast to the analytic mode. Klein was systematising the whole thing while Poincaré was doing the same for topology.
All this would have been in Frege's mind when he made his remark.
I do not think he was entirely correct, but that is one for the maths StackExchange.

Why Frege thinks geometry is synthetic?


React Native Dev Menu not Appearing

Question: I'm debugging a React Native app in the AVD Android Emulator running a Nexus 5X API 27 Oreo on Windows 10, and the developer menu will not show using the steps mentioned in this StackOverflow question How do you debug React Native?

Using Ctrl + M on the emulator enables the multi-gesture action instead of the dev menu. Windows + M minimizes all open windows. I have also tried going into Settings > Send keyboard shortcuts to > Virtual device.
Using the adb shell input keyevent 82 command does not do anything. I tried going into adb shell and running the command input keyevent 82.
Shaking the device using Virtual Sensors > Accelerometer does not bring up the menu by shaking the device.
Upgraded from API 27 Oreo to API 28 Pie.

So far I was able to open the Dev Menu using Step 2, but it stopped working all of a sudden, without any changes to the React Native code as far as I know. I tried running it on a physical device and shaking it worked as expected.
Answer: For me this happened when I connected a real device at the same time as the simulator was running.
After real device was disconnected and app was rebuilt Cmd+M (Mac OS) worked again.

React Native Dev Menu not Appearing


What are some ways to check metagenomic bin quality?

Question: I am new to metagenomic binning. I've used CheckM in order to estimate completeness and contamination values, and most of my bins of interest appear to have good values. My workflow was pretty straightforward (BBDuk for quality control > Megahit for assembly > vamb for binning). What else could I do / where do I go from here? (especially regarding quality control)
Answer: Some papers check 5S, 16S, 23S and ≥18 tRNA genes for completeness. For example, you can see this paper.
Answer: There are many other tools. If you want to get nice statistics and graphs I recommend Amber, there is also Anvio for manual refinement of the bins.


Postgresql fatal error

Question: I am using postgresql. By mistake i gave permission to the postgresql folder through the command
chmod -R 777 /var/lib/postgresql/

Now that when i am trying to connect to postgresql it is giving me the following error.
The PostgreSQL server failed to start. Please check the log output:
2013-09-19 07:21:48 GMT FATAL:  data directory
"/var/lib/postgresql/8.4/main" has group or world access 2013-09-19
07:21:48 GMT DETAIL:  Permissions should be u=rwx (0700).

tried restarting postgresql server through command
/etc/init.d/postgresql restart

but getting the same error.
what shall i do?
Comment: chmod -R 700 /var/lib/postgresql/ ?
Comment: Doesn't the message already tell you what you should do …?
Answer: PostgreSQL requires exclusive access to the files in the data directory.  This is fixable depending on your operating system by using chmod 700 on the data directory or by right-clicking, and selecting various options on Windows.

Postgresql fatal error


Is there any wisdom behind "and", "or" operators in Ruby?

Question: I wonder why ruby give and, or less precedence than &&, || , and assign operator? Is there any reason?
Answer: My guess is that's a direct carry-over from Perl. The operators or and and were added later in Perl 5 for specific situations were lower precedence was desired.
For example, in Perl, here we wish that || had lower precedence, so that we could write:
try to perform big long hairy complicated action     || die ;

and be sure that the || was not going to gobble up part of the action. Perl 5 introduced or, a new version of || that has low precedence, for exactly this purpose.
An example in Ruby where you could use or but not ||:
value = possibly_false or raise "foo"

If you used ||, it would be a syntax error.
Comment: Is there a name for the idiom of do_something or die? Does it get used in ruby?
Comment: I don't know of any name for it, but it's fairly common in Ruby.
Comment: Perl leans heavily on die, whereas Ruby uses raise. The advantage of an exception is you can rescue it.
Comment: Although technically you can rescue from a die, people don't usually bother unless it's really important. It's too much of a nuisance.
Answer: The difference is precedence. ||, && have higher precedence than =, but and, or have lower. So while you can do:
a = nil || 0

You would have to do:
a = (nil or 0)

to get same effect. If you do:
a = nil or 0

The result of expression would still be 0, but a value would be nil.
Answer: They have very low precedence so that the operands don't have to be wrapped in parentheses, as is sometimes the case with && and ||.
Answer: Being able to control the precedence of your operators is sometimes useful, especially if you are concerned with readability -- extra parenthesis in conditional statements can sometimes obscure the actual logic.
To be frank, though, I think the reason Ruby has the boolean operator precedence levels it does stems mostly from the fact that Matz was a Perl programmer before he ever wrote Ruby, and borrowed much of the core syntax and operators from that language.
Comment: hmm, that explains why ruby is so immature and at the same time so much bloated. Still hard to wrap my head around that..
Answer: I believe the idea is specifically to get them below the assignment operators, so you can write logic tests with assignments but without parens.


8386 Ferrari F1 Racer convert to an RC

Question:
Help convert 8386 Ferrari F1 Racer to an RC
Comment: It probably wouldn't be too hard to replace the steering yoke with a Power Functions Servo Motor, and the engine block with a Power Functions motor. Although battery pack and IR receiver might have to sit on top. I don't have this model myself to experiment with though.
Comment: Alexander thank you for the advice! Before I begin with the conversion, ideas and suggestions from you guys with experiences would lesser the job. I am just starting collecting some pieces available from my place. That is why I got interested more and more with lego.
Answer: If you are looking for direct instructions converting this set to RC you won't probably find it here. It is just a big of a job for such a simple request.
However I could suggest placing PF Servo motor where the steering wheel is and PF L-motor where fake engine sits. You can probably fit smaller PF battery box in one of the side covers with fake radiators. And PF IR-receiver can be placed wherever it is convenient. Don't forget you need PF remote control to drive your model. There shouldn't be a need for extra gears if motors placed in suggested places.
I can also suggest to try converting such set to RC on your own. It has plenty of space, a lot of potential to gain experience and shouldn't be a big of deal to convert. It might not look great on the first iteration, but with a bit of persistence and more practise you can make it look much better.
Comment: Alex thank you for detailed instructions. I just bought a new set of +power functions (8293) however I still don't have the remote control piece and another motor. I wished I could upload a picture of it here in comment section, is this not possible? Again thank you!
Comment: @allan 8293 set won't be much of a help here, unfortunately. The M-motor, this set has, isn't powerful enough to move the model. There's also other bits missing required for motorization. PF elements provided in the answer are quite expensive. So the most cost efficient way of getting them is by finding used 9398 or 42030 set. These contain all the elements you need for motorization, except small PF battery box, since both sets come with a larger one. But it can be fit into model too.

8386 Ferrari F1 Racer convert to an RC


How to compute certificates using Diffie-Hellman key exchange with certificates and Elgamal signature scheme

Question: We consider the Diffie–Hellman key exchange scheme with certificates. We have a system with the three users Alice, Bob and Charley. The Diffie–Hellman algorithm uses p = 61 and α = 18. The three secret keys are a = 11, b = 22 and c = 33. The three IDs are ID(A)=1, ID(B)=2 and ID(C)=3.
For signature generation, the Elgamal signature scheme is used. We apply the system parameters p= 467, d= 127, α= 2 and β. The CA uses the ephemeral keys kE = 213, 215 and 217 for Alice's, Bob's and Charley's signatures, respectively.
To obtain the certificates, the CA computes xi = 4*bi +ID(i) and uses this value as input for the signature algorithm. (Given xi, ID(i) follows then from ID(i) ≡ xi mod 4.)

Compute three certificates CertA, CertB and CertC.
Verify all three certificates.
Compute the three session keys kAB, kAC and kBC.

I am confused on how to solve for this problem. The book does not really clarify how to do it well.
In particular I have no idea what the 'bi' used to solve for xi in the signature is.
For Example: to get certificate A I know that I need to find CertA = [(kA,IDA),sig(kA,IDA)]
To find kA(the public key), I do α^a mod p (which I found to be 10)
To find the signature, I do Sa = (x-d*r)*kE^(-1) mod p-1, where r=  α^(ke)mod p
The question says that xi = 4*bi +ID(i), which would be the x, but I don't know what the bi is referring to, so I don't know how to solve for the signature.
And for the verification step, it says ver_subK_subpub,CA(CertB), but it does not say what the verification function is anywhere. How do I verify if it does not say how to?
Answer: I am currently working through this myself. I believe that the variable $b$ refers to the public key, which you will find using the $\alpha^a \bmod p$ equation you mentioned. Given that, you have all the information you need to find $x$.


Could information be transferred through a wormhole?

Question: There was a paper published recently about the possibility of sending messages through a wormhole,see reference here. It has also been speculated that any entangled pair of particles—even particles not ordinarily considered to be black holes, and pairs of particles with different masses or spin, or with charges which aren't opposite—are connected by Planck scale wormholes  see reference here. We also know that quantum reflection involves the Casimir - Polder interaction. Putting these things together,  is it possible that the  wedge-modified path-entangled EPR experiment with variable entanglement in the Herbert - Cramer paper, section 6 might have something to do with these phenomena ? The signal is very weak, but a statistical reproduction of the experiment could in principle detect such a signal, see figure 8 in the Herbert-Cramer paper. I realize the question is highly speculative,but I am interested in a hunch, not a full complete answer,  coming from someone with proper expertise in the physics involved, which I don't have.
Answer: In your 1. and 2. link they require ghost matter, which is unphysical. Nevertheless, if you had enough of this ghost material you could compensate for the collapsing effect real matter would have on the wormhole.
So you could either send a ghost particle through without risking to collapse the throat, or send a real particle accompanied by one or two ghost particles. Since there is no ghost matter in this universe that won't work for real though.
Your 1. link is amateur nonsense by the way, since they claim "Theoretically, ghost matter responds to gravity in exactly the opposite way to normal matter. That is, a ghost matter apple would fall up from a tree branch instead of down. While allowed by Einstein's theory of general relativity..." which is wrong since gravity is not a force but geometry.
Relativity only allows for (also unphysical) negative matter which itself is gravitationally repulsive, but an apple made of negative matter would still be attracted to the earth while slightly repelling the earth, which in the case of opposite masses with the same magnitude would lead to the formation of a so called runaway pair.