running apache on fedora/selinux/no setroubleshoot messages on desktop

Question: I have installed fedora 24 installed from scratch via iso image.
I have httpd started and can see the default page if I access "localhost".
Now I want to add a directory which should contain files for download. I
simply added these files to the new directory like:
<code>/var/www/html/tar-packages/
</code>
I tried to access from browser: "localhost/tar-packages"
apache error log:

[Mon Jun 27 18:28:57.903136 2016] [autoindex:error] [pid 24823] (13)Permission denied: [client ::1:53204] AH01275: Can't open directory for index: /var/www/html/tar-packages/

OK, the file permissions and httpd.conf is fine. I have a look in selinux:

type=AVC msg=audit(1467044937.902:1659): avc:  denied  { read } for  pid=24823 comm="httpd" name="tar-packages" dev="dm-0" ino=1453837 scontext=system_u:system_r:httpd_t:s0 tcontext=unconfined_u:object_r:user_home_t:s0 tclass=dir permissive=0

OK, the problem is related to selinux.
But now I am wondering!
Q: Why I got no alert message on my desktop and how can I configure that? On fedora 23 there comes up a little message box with a simple info which selinux command I can enter to get the problem fixed. How can I enable this tool on my new fedora 24 system?
BTW: If someone can also fix the access problem on my http server is also fine.
But more important is to get the alert messages again on my desktop system. It was really helpful for the older fedora distributions.
Answer: try running <code># restorecon -rv /var/ww/</code>
Comment: http://serverfault.com/help/on-topic, httpd in a desktop environment is hardly an on-topic question here. Maybe in superuser you will have more luck with your linux desktop question
Comment: Thanks, that's enabled my new path in the apache config, but the important part of my question "how to enable the pop up messages" are still open...


Is it possible to export LinkedIn contacts with city and state?

Question: I'm following the directions to export LinkedIn contacts and it does work, but the resulting export file has blank values for most of the fields, including city and state.  Is there a way to export that does include this information?
Answer: No. You are getting all the possible data now. Sorry
Answer: As a recruiter, I've been trying to find an answer for this for years. There was at one point a way to do this with a LinkedIn API token but LinkedIn blocked this functionality in 2015.  LinkedIn will never download the locations with the candidates and doing it manually would take 80+ hours of manual entry.
Here at Moonlight we worked on this problem for over a year and thoroughly searched for a company or software that can do this. To our knowledge, there is no one that can do this
Moonlight Strategic Search has developed a way to take any LinkedIn excel contacts file and fill out the locations of the people. You can order the service here:
http://www.moonlightstrategicsearch.com/linkedin-data-locations/
Comment: I'm still not enthralled with this answer, either.   While you disclose your affiliation with the product, this answer seems to exist solely to promote your service.  The question is asking how to export *from* LinkedIn with that information intact.
Comment: @Logan: are you saying that your service does some localization work unrelated to LinkedIn?
Comment: Once you have the company name you can just do a lookup on Google Places API and throw out any with multiple matches (uncertain location).


How to navigate easily in aarch64 assembly listing

Question: I have an obfuscated aarch64 (64 bits ARM, aka armv8) binary that I am trying to understand. This program decodes/decrypts machines instructions from its .data section, stores them into memory and then jumps to this address.
I am able to retrieve the machine intructions using the following gdb commands. As mentioned above, these intructions cannot be obtained using objdump because they are encoded/encrypted and the binary decrypts them at runtime.
set log on
x/2000i 0x******
set log off

This produces a gdb.txt file in the working dir containing an aarch64 assembly lisiting :
[...]
0x400ee4:   svc #0x0
0x400ee8:   orr x3, x0, x0
0x400eec:   mov w2, w3
0x400ef0:   mov w1, #0x1                    // #1
0x400ef4:   orr x0, x20, x20
0x400ef8:   bl  0x402660                    // Jump instr
0x400efc:   mov w1, #0x3                    // #3
0x400f00:   orr x0, x20, x20
[...]

I would like to able to :

Jump to an address using a shortcut : For example, I would like to able to click 0x402660 in the instruction bl  0x402660 and press F3 to jump to the line starting by 0x402660. I would also like to be able to go back to where I was using another shortcut.
Generate a control flow/graph

Of course, you can suggest any combination of tools/scripts that would work (i.e. if you think the best way to do this would be to import the listing in Excel and write VB macros, that's fine). However, keep in mind I have an aarch64 binary (so many tools are not compatible with this architecture) and that my binary decodes its machine code at runtime.
Comment: are you using ARM Foundation models or Qemu ? I'm trying to use gdb to debug a binary of mine running on the Foundation models but so far I can't manage to attach it the way I do with Qemu.
Answer: The best tool for this would be IDA Pro Advanced.
There is a specific stack exchange site for this kind of questions : https://reverseengineering.stackexchange.com/
For your specific binary, it's not a normal binary, obfuscation is there to make the challenge more interesting :) (for those wondering what this is about)


Get rid of stray dog's urination

Question: I am venkat, from Chennai,India, staying in a Apartment. We are facing a problem with our neighbhour pet dog which urniates in our car&bike parking area. I have requested the owner of the don in this regards but thet least bother about it. Is there any way to stop this? Pls advice.
Comment: Nothing that doesn't involve chasing the dog or the owner, no. The dog is marking it's territory so other dogs know it is in the area. Unless you move the territory line somehow (for example but putting up a fence) of the dog's owner does so (by keeping it off your parking area,) the dog will continue to want to mark there. Generally a bit of dog pee doesn't harm anything though...
Comment: If that dog don't do it. Another one will come up. Actually more then one will come up. It is good to have one instead of more.
Answer: Dogs tend to frequent certain spots to go potty, and nowhere else. Hopefully, this is just a minor issue and this post was geared towards increasing rep rather than trying a list of suggested ways to repel this dog from your parking area... So if nothing else works, before taking the hose to him (effective 100% of the time) , mix a little water in with some chili pepper flakes and apply to desired area a little while before the dogs usual potty break.  Dogs identify their toilet with the nose, and he'll soon find another area that he'll mark as his.

Get rid of stray dog's urination


If a bowler's front foot is on the line and no part of the foot is behind the line, is it a fair delivery?

Question: If a bowler's front foot lands on the line and some part of the foot is outside the line and some part of the foot is on the line but no part of the foot is behind the line, is it a fair delivery?
Answer: The way you describe it, its a no ball.  To be a legitimate delivery some part of the foot whether raised or grounded must be behind the popping crease No Ball.
Answer: Here's what the official Laws of Cricket documentation by the MCC says on no-balls:

the bowler's front foot must land with some part of the foot, whether grounded or raised

I don't see how what you're saying is physically possible. Even if some part of his foot is behind the line, whether on the ground or in the air, it's a fair delivery. The alternative to that would be a player having his entire foot directly above the line, which doesn't sound like a plausible situation to me.
Answer: 21.5 Fair delivery – the feet
For a delivery to be fair in respect of the feet, in the delivery stride
21.5.1 the bowler's back foot must land within and not touching the return crease appertaining to his/her stated mode of delivery.
21.5.2 the bowler's front foot must land with some part of the foot, whether grounded or raised
-       on the same side of the imaginary line joining the two middle stumps as the return crease described in
21.5.1, and
-       behind the popping crease.
If the bowler's end umpire is not satisfied that all of these three conditions have been met, he/she shall call and signal No ball.  See Law 41.8 (Bowling of deliberate front foot No ball).


Override cache-control header on client side using JavaScript?

Question: Is it possible for a client to override and/or ignore HTTP Cache-Control headers of dynamically-loaded content (e.g. images loaded asynchronously) using JavaScript?
My JavaScript-based GIS application requests images dynamically from an outside server who sends the following header with its response:
<code>Cache-Control:max-age=0,must-revalidate
</code>
This results in the browser sending duplicate requests for the same images (along with If-None-Match request header) which always results in an HTTP 304 Not Modified response, so the cache is used anyway but only after a delay.
I already know the images have not changed, but I don't have any control over the cache-control header sent by the server, so I would like to force use of the local browser cache when displaying the image without having to first revalidate with the server.
Is it possible to change this on the client side?
Answer: You should be able to override the local cache from javascript by doing a location.reload(true) but not all browsers behave properly - use a frame to repopulate non html content


Plasma Stability

Question: Plasma consists of positive(ions) and negative(electrons) charges. Ions repel each other, so do the electrons, in the mean time ions attract electrons and vice versa, what will be the net result? Does the plasma tend to collapse or expand or stay in constant density? Why is it stable?
Comment: You might want to specify the boundary conditions a bit more - are you asking about what will happen if you put a blob of plasma into vacuum?
Comment: Yes "what will happen if you put a blob of plasma into vacuum", Thanks.
Answer: If you start with a blob of hot plasma in vacuum without any internal structure, the kinetic energy of electrons and ions will be too large in comparison with the energy of EM interaction for such blob to exist in equilibrium, so the plasma will expand rapidly -- like a gas --  at about the speed of individual particles.
However, one can form from plasma more interesting type of configurations, if one remembers that there can exist considerable currents in plasma and hence magnetic fields. The magnetic field generates its own form of pressure that can stabilize plasma structure. In plasma confinement structures (tokamaks, tandem mirrors etc.) such magnetic field is generated by external sources, but it is possible for the magnetic field to be generated by currents inside the plasma itself. Such structures are called plasmoids. Such plasma structures can form in astrophysical conditions, in laboratories and even in atmosphere (presumably ball lightning is such).
There are some general results (most notably Chandrasekhar-Fermi virial theorem) that tell that absolute stability for such structures in the absence of external fields is impossible, but lifetimes of plasmoids could be considerable.
Finally if the blob is large and massive enough -- astrophysical scale -- it can be stabilized by gravity. This will result in formation of a star or star-like object (such as brown dwarf).
Answer: Well, plasmas are actually inherently unstable.  Meaning, they will not relax to a Maxwellian velocity distribution in many cases unless the collision rates are very high (e.g., in the sun's chromosphere and below).
Plasmas tend to have sources of free energy (e.g., non-Maxwellian features like relative streaming of two groups of particles or temperature anisotropies) because they are not in thermodynamic equilibrium.  These sources of free energy can result in plasma instabilities, which do not necessarily act to relax the plasma to a Maxwellian.  They do, however, act to remove the source of free energy that caused them in the first place.  This is accomplished through the radiation of electromagnetic waves, which then reduce the free energy source further by acting on the particles responsible for the free energy.
To address your question directly, we must start a little simpler.  For an ionized gas to be considered a plasma, there are several requirements but the two most relevant to your question are related to the Debye length, $\lambda_{De}$.  The first is that the gas satisfy $N_{D} \lambda_{De}^{3} \gg 1$, or that the number of particles in a Debye sphere be very large such that the gas can exhibit a collective behavior.  The second derives from the first and is called quasi-neutrality.  This requires that $n_{e}$ = $\sum_{s} Z_{s} \ n_{s}$, where, $Z_{s}$ is the charge state of ion species $s$ and $n_{s}$ is the number density of particle species $s$.  Both of these requirements/assumptions imply that on scales larger than $\lambda_{De}$, the collective Coulomb fields of the charged particles will shield each other out.  Meaning, on scales larger than $\lambda_{De}$ there should be no collective quasi-static electric fields.
This is why a plasma would not endlessly expand or collapse.
Answer: If you just put a blob of plasma into vacuum it will expand. Since the electrons and ions are not bound together and just moving chaotically it will be similar to using a mixture of two fluids (which is actually one of the ways of looking at plasma - as two fluids interacting together through collisions and EM field). You'll get some recombinations, some electrons/ions will escape as they are. In case of atomic ions some can even lose additional electrons in the collisions. The exact ratio of the final products will depend on the initial state - higher temperature plasma will expand more rapidly, colder will end up with more recombinations.
If you put in an initial EM field, the situation changes entirely - again depending on the particular conditions. In some cases it may resemble for example what happens in a tokamak.
Comment: Charges are not bound together but at least we know that the plasma does not let the charge separation. So the electric forces cause a sort of collective bound state! Now the question is that can these forces prevent the plasma from expansion?
Answer: Basically, there is an industrial process based on the expansion of a plasma in vacuum: pulsed laser deposition. It forms a kind of plume that deposits material on a substrate, to grow special films like large mono-crystal superconducting films. Very beautiful phenomenon, by the way.

Plasma Stability


Power Series Solution of $y''+y=0$, and Summation Indices

Question: I have a general question about this following problem \begin{equation} y''+y=0\end{equation} The required method to solve this problem is based on generating the power series solution, using the power series method. I began my problem by setting up the summations. \begin{align}\sum_{n=2}^\infty(n)(n-1)c_nx^{n-2}+\sum_{n=0}^\infty x^nc_n&=0\end{align} Then I did two substitutions, and then got to the following equation: \begin{equation}\sum_{k=0}^\infty[(k+2)(k+1)c_{k+2}+c_k]x^k=0\end{equation} Then I set the part that I know could zero out which was the inner portion of the sum: \begin{equation}(k+2)(k+1)c_{k+2}+c_k=0 \end{equation} Then I get the following equation: \begin{equation} c_{k+2}=-\frac{c_k}{(k+2)(k+1)}\end{equation} After that I decided to do the following and break it apart into a table: \begin{array}{|c|c|}k=0&k=1\\c_2=-\frac{c_0}{2\cdot1}&c_3=-\frac{c_1}{3\cdot2\cdot1}\\ \hline k=2 & k=3 \\ c_4 = \frac{c_o}{4\cdot 3\cdot 2 \cdot 1} & c_5 = \frac{c_1}{5\cdot 4\cdot 3\cdot 2\cdot 1}\end{array}
Based off the pattern I that sgn changes, and that there is factorial in the denominator is my attempt right thus far, and how to collaborate them into a power series solution?
Comment: Are you just trying to find a formula for the general $c_k$ term? You seem to have a good idea of the formula, so why not use induction?
Comment: In my note book I figured out its sine and cosine but I get lost with how to isolate them into those two solutions
Comment: You need to use Taylor series of sine and cosine functions +1
Answer: From your work it follows inductively that for $n\geq0$,
$$c_{2n}=\frac{(-1)^n c_0}{(2n)!}, \qquad c_{2n+1}=\frac{(-1)^n c_1}{(2n+1)!} .$$
So we find that
$$\begin{align}y(x)&=\sum_{n=0}^\infty c_nx^n
=\sum_{n=0}^\infty  c_{2n}x^{2n}+\sum_{n=0}^\infty  c_{2n+1}x^{2n+1}\\
&=c_0\sum_{n=0}^\infty \frac{(-1)^nx^{2n}}{(2n)!}+c_1\sum_{n=0}^\infty \frac{(-1)^nx^{2n+1}}{(2n+1)!}=c_0\cos(x)+c_1\sin(x).\end{align}$$
Comment: Yeah its at ordinary points so your answer is right I am just waiting.
Answer: Your attempt looks  correct to me. You can use the Taylor series definition of:
$$\cos (x)=\sum_{n=0}^\infty (-1)^n\dfrac {x^{2n}}{(2n)!}$$
$$\sin (x)=\sum_{n=0}^\infty (-1)^n\dfrac {x^{2n+1}}{(2n+1)!}$$


Can an opponent make me discard a Miracle card before I cast it, after it is revealed?

Question: For example, if my hand is empty and I draw and reveal Temporal Mastery, can an opponent cast Funeral Charm and make me discard it before I have a chance to cast it for its Miracle Cost?
Answer: Yes. Miracle triggers upon revealing the card when you draw it. You cannot cast the card until the triggered ability resolves and you pay the cost. Until that time, the card is in your hand and subject to the effects of discard.

702.93. Miracle
702.93a Miracle is a static ability linked to a triggered ability (see rule 603.10). "Miracle [cost]" means "You may reveal this card from your hand as you draw it if it's the first card you've drawn this turn. When you reveal this card this way, you may cast it by paying [cost] rather than its mana cost."
702.93b If a player chooses to reveal a card using its miracle ability, he or she plays with that card revealed until that card leaves his or her hand, that ability resolves, or that ability otherwise leaves the stack.
Comment: Won a game once by using Surgical Extraction on Bonfire of the Damned in response to my opponent revealing a second Bonfire. Good times.
Answer: It depends on whether the Miracle card is a Sorcery or Instant
It would be correct to say: Your opponent can make you discard a Miracle card before you can cast it for its Miracle cost, as user1873 already pointed out.
If the card is a sorcery, you can't usually play it outside the main phase or with a non-empty stack, so for your specific example, he could make you discard before you can cast it in any way.
If it's an Instant, however, you can still play it for its regular cost in response to the Funeral Charm.
Comment: If you are casting it as a Miracle the Avacyn restored FAQ says specifically that you ignore timing restrictions.  I am not sure the Sorcery vs Instant applies to this question.  [Restored FAQ](http://www.wizards.com/magic/magazine/article.aspx?x=mtg/faq/avr)
Comment: @Akedren We already established that the Charm is faster than the Miracle alternative cost. The original question asked whether the card can be played at all, and if the Miracle card is an Instant, it can be played for its *regular* cost rather than its Miracle cost, in response to the Charm. You can **choose** between Miracle and regular cost, you are not forced to play it for its Miracle cost if you reveal the card.
Comment: Indeed, I was wondering about paying the Miracle Cost. I have clarified the question to reflect that.


Can anyone explain C code of a condition variable's signal being broadcast to all waiting threads using pthread_cond_broadcast()?

Question: Can anyone explain C code that demonstrate the use of a condition variable's signal being broadcast to all waiting threads using pthread_cond_broadcast() ?
Comment: Section 3.3 of Dave Butenhof's famous book (http://www.amazon.com/Programming-POSIX-Threads-David-Butenhof/dp/0201633922) has a great explanation. Also, you can find very good discussion of signal/broadcast in http://www.domaigne.com/blog/computing/condvars-signal-with-mutex-locked-or-not.
Answer: pthread_cond_broadcast() should be used when multiple threads may be waiting on the condition variable, but some of those threads may not be ready to proceed.  pthread_cond_signal() might wake up one of those threads; pthread_cond_broadcast() wakes them all, so that if any can proceed, one will.
For example, we might have a mutex protecting two variables x and y.  Some threads wait on this condition:
pthread_mutex_lock(&mutex);
while (x < 10)
    pthread_cond_wait(&cond, &mutex);

whereas others wait on this condition:
pthread_mutex_lock(&mutex);
while (x < 10 || y < 5)
    pthread_cond_wait(&cond, &mutex);

If a thread increases x above 10 but leaves y less than 5, then it should use pthread_cond_broadcast(&cond), because any threads waiting on the second condition aren't ready to run yet, so we have to ensure that at least one thread from the first condition is woken (if there are any waiting on that condition).
The other situation in which pthread_cond_broadcast() can be used is when all waiting threads can proceed (eg. when a group of threads should stop waiting and exit).
One thing to keep in mind for correct code is that pthread_cond_signal() is an optimisation, nothing more - if your code is correct, then it should also work if every pthread_cond_signal() were replaced by pthread_cond_broadcast() (but perhaps not as efficiently).


Which classes in a JSF web application need to be Serializable?

Question: Does the User class from the question JSF Controller, Service and DAO need to be serializable?
Answer: Once the server throws java.io.NotSerializableException, then the class name will just appear in the exception message. It's sufficient hint that the server expects the class to be Serializable.
Usually, it are those classes which (in)directly end up in the HttpSession, because the server may need to convert (serialize) all HttpSession instances to InputStream/byte[], so they can be saved to local disk file system to remember open sessions during a restart, or transferred over network when being placed in a cluster.
In a JSF (+CDI) web application, all @ViewScoped, @FlowScoped, @ConversationScoped and @SessionScoped beans will (in)directly be saved in the HttpSession. So, it's obvious that at least those beans and all their properties need to be Serializable.
As to general design practice, anything which is classified as "Java Bean" throughout the codebase needs to implement Serializable. This is even mentioned in JavaBeans Specification. This only won't be actively used when it concerns e.g. a @RequestScoped or @ApplicationScoped bean, so that's why most developers just omit them from those beans. From the other side on, a java.io.NotSerializableException could be a good hint prevent the developers/maintainers from (re)using backing beans in the "wrong" scope than where the backing bean is originally designed for.
See also:

java.io.WriteAbortedException: writing aborted; java.io.NotSerializableException
What is a JavaBean exactly?
Answer: Every Class in your JSF application has to implement the serializable interface.
If you want to override this, use the transient keyword to skip serialization of unserializable classes.
Additional info :

Serialization of Objects explained:

It lets you take an object or group of objects, put them on a disk or send them through a wire or wireless transport mechanism, then
later, perhaps on another computer, reverse the process: resurrect the
original object(s). The basic mechanisms are to flatten object(s) into
a one-dimensional stream of bits, and to turn that stream of bits back
into the original object(s).
Like the Transporter on Star Trek, it's all about taking something complicated and turning it into a flat sequence of 1s and 0s, then
taking that sequence of 1s and 0s (possibly at another place, possibly
at another time) and reconstructing the original complicated
"something."
isocpp.org(Serialization and Unserialization)

What is the use of transient variables?


What does it mean when your male dog asks to be mounted by your female dog?

Question: For a while now my male dog (blue heeler) will ask to be mounted by my female dog (blue heeler/lab mix). He will rub up against her and then push his butt into her face. He will do this several times until she mounts him. He's only a year and a few months old and has not yet been neutered. It's very odd and he will do it many times a night. Why is he doing this?
Answer: I have a female Labrador Retriever. The frequency of her unconventional sexual behavior decreased after getting her spayed.
At around 10-11 months old she had her first heat cycle and started behaving quite strangely around the house, most specifically to her bedding (round bed about 4 feet in diameter). She would flip the edge of the bed up under herself and start grinding/humping it for 5 seconds, then jumping away from it while growling and repeat the process 1-2 more times. She would do this multiple times per day. The act of humping most commonly is the action of a male dog, so it was extra strange to witness this.
Once we had her spayed, we thought the behavior would go away completely, but it didn't. She does however do it less frequently (1-2 times a week, that we witness).
She has been spayed for a year now, and the behavior has lessened but not completely gone away. In your case, if you plan to neuter him, it may decrease the frequency like it did for us.
UPDATE
She's over 4 years old now and still continues to do this. It most commonly occurs when she is overly excited about something (wrestling, chasing, just finishing getting a bath, coming in from a walk, etc...)


What is ant build file and maven build file?

Question: Can somebody please tell me in simple words what exactly is ant build file and maven build file?
Answer: They are XML files that describe how to build and package software (usually Java software).
Ant files are used by the Ant tool, which provides more flexible, free-form builds.  An Ant build file is much like a program in its own right (only encoded as verbose XML).
POM files are used by Maven, which has a different philosophy and imposes more structure.  The Maven approach is more declarative than Ant.  Writing a Maven build is less like writing a procedural program to build the software.
Comment: The tools provide the functionality (e.g. compilation, archiving, running unit tests) and the XML files define how this functionality is used.
Comment: So basically, they are sort of a template for us to build on...they do not provide any ready-made functionality! right?
Comment: Suppose I am developing a Struts2 Web app...then how will they help me?
Answer: They're just like any other build files (NAnt, make, ...).
They describe the steps taken to produce some kind of artifact - an executable file, a test run, etc.
The build file will describe how to create a clean build environment, what to compile, where the dependencies are that you need to compile, where to put the executables, DLLs, and the like, any additional programs you need to execute (like running your testrunner on your project, or instrumenting your code so a coverage tool can analyse your test coverage).


Passport validity to enter Canada

Question: I need some information. I intend to travel to Canada from 13-29 October. I am a Pakistani national and I am traveling from Germany to Calgary by KLM Airlines. My passport validity is until 12 January and my visa validity is until 11th January. Can I travel with my existing passport or should I renew my passport?
Comment: Will you be returning to Germany after you leave Canada?  Will your passport validity be sufficient to return to Germany?
Answer: You will be fine.
According to this website of the Government of Canada, if your passport expires before the end of your intended visit, the immigration officer can limit the length of your permitted stay to the length of your passport validity.  You're leaving before your passport expires, so you'll be fine.
The "expiry" date of your visa is the last day you may arrive; it isn't actually your maximum visit end date.  But if you came on January 11, you'd be turned around since your passport would expire that night.
Comment: Not to mention that Canada typically does not issue visas which expire after the passport they are placed in.

Passport validity to enter Canada


Which yum group(s) contain a given package?

Question: Is there a way to ask yum which group(s) contain a given package? I know how to ask what packages are in a given group, and could write a quick script to trawl over all of the groups, but it would be nice to have a simpler mechanism than that.
Answer: If you are only looking for a 'simpler mechanism' to be used by a human and don't need it in some kind of script or so, you might get by with this one:
yum groupinfo '*' | less +/sendmail-cf

Of course, replace sendmail-cf with the package name you're interested in.
Comment: Thanks, yes just human usable is what I was looking for, so this fits the bill!
Answer: You can find a group to which the specified package belongs, by using yum-list-data plugin.
$ sudo yum -y install yum-plugin-list-data

$ yum -C list-groups ftp
Loaded plugins: fastestmirror, list-data
==================== Available Packages ====================
Console internet tools      1 (100%)
list-groups done

Or, if you are not allowed to install the plugin, please save the following script and try to run it with one argument, the name of the package you try to find:
#!/bin/sh

search_name=$1
LANG=C yum grouplist -v | grep "^  " | awk -F'(' '{print $1}' | sed -e 's/^ *//' | while     read line
do
    if [ "${search_name}" != "" ]; then
        yum groupinfo "${line}" | grep -q "^ *${search_name}$"
        if [ $? -eq 0 ]; then
            echo ${line}
            break
        fi
    fi
done

Answer: I don't know about yum, but remember that it sits on top of rpm. The rpm command you're looking for is:
rpm -q --qf %{group} yourRPM

You might want to add a \n at the end, depending on that you are up to:
[root@Niflheim ~]# rpm -q --qf %{group} setarch
System Environment/Kernel[root@Niflheim ~]# rpm -q --qf "%{group}\n" setarch
System Environment/Kernel
[root@Niflheim ~]#

Comment: Interesting thought, but it does not return a group name that matches anything given by 'yum grouplist'


Is there an arithmetic book similar to "Teach Your Child to Read in 100 Easy Lessons" by Siegfried Engelmann?

Question: I have found Engelmann's book (mentioned in subject) to be extremely effective.  Is there an equivalent to this book for teaching Arithmetic?  I believe the overall approach or method is called Direct Instruction.
Comment: At amazon.com [this book](https://www.amazon.com/dp/0671631985) currently has 5,209 ratings! I haven't paid attention to which book I've viewed at amazon.com over the past 15+ years has the most number of ratings, but surely this book surpasses the maximum I've ever seen by a factor of at least 100.
Comment: @DaveLRenfro yes that's the book for teaching children to read I referenced above. I'm looking for the arithmetic equivalent of that book.
Answer: I decided to write my reply as an answer because I feel strong about both reading instruction and early math education. I hope that neither the original question nor this reply will be edited, because the question is very typical to how many approach education. But feel free to skip the rant below to the recommendation of a book.
Listicles in education
The listicle-style title of the reference book is a tell-tale sign of a cookbook-style instruction. Listicles are fine for presenting a collection of disparate unrelated items, like 50 Italian pasta recipes or 100 best American poems. But when used in education, this approach forcefully squeezes or more often extends the subject matter and pedagogy into a Procrustes bed of arbitrary number of steps. This usually results in a bloated course with boring, repetitive and often nonsensical steps students have to follow.
Engelmann's book is 400-page long. Does it really take this long to learn to read? The book refers to "Why Johnny Can't Read" by Rudolf Flesch as an inspiration. Well, Flesch's is a good book. The first two thirds of it is a seething critique of Look-Say / Whole Language / Balanced Literacy approach, and the last twenty pages or so is a compact yet very methodical primer to teach reading phonetically. His book is a much better choice both as an insight into phonetic reading instruction as well as a reading primer.
Engelmann's book, on the other hand, is bloated with repetitive "direct instruction" script, but what ruins it completely in my opinion is non-standard grammar. To represent sounds the book uses symbols that are neither from English alphabet nor from International Phonetic Alphabet. The pronunciation guide recursively defines these funky symbols using the same symbols, like "ē" must be pronounced as "ēēē" (IPA symbol is /iː/), "sh" is pronounced as "shshsh" (IPA symbol is /ʃ/), "th" is pronounced as "ththth" (IPA symbol is /ð/ for voiced and /θ/ for voiceless consonant). Such nonsense. The symbol "ɪ" is used to represent the same sound as in the word "I" with complete disregard that in IPA the same symbol represents a sound like in "bit". Instead of giving clear instructions how to read open syllables in words like "take" (for example, "letter 'e' at the end makes preceding vowel sound like it is spelled in alphabet") Engelmann's book diminishes the terminating "e" and puts a bar over "A" to indicate that it is a long vowel, like "TĀKe". "A" in the word "take" sounds like /eɪ/ not like /ɑː/, throwing off anyone who may think that the bar means simply elongated sound.
What does the bar mean then? The book uses the bar for words like "for", "shore" and "go", writing them as "fōr", "shōre" and "gō", but is the "o" pronounced the same in these words? Regional dialects may be different, it can be something like /fɔr/, /ʃɔːr/ and /goʊ/ — these are three different sounds: "short o", "long o", and a diphthong. Between inconsistent symbols and non-standard grammar, how kids are supposed to switch to regular English? It does not have bars over letters. Does the book implicitly suggest that kids will memorize the words with the bar so they would be able to read them later without the bar? How is this better than explaining how the sound changes depending on other letters around?

There are many books like this intended for math education. Their writers are often former elementary school teachers who have discovered a well-known practice on their own, and being happy of this amazing achievement they want to share their newly-found knowledge with everyone else, giving it a new fancy name in the process. Clearly, the job of a consultant in education pays better than of a regular teacher and comes with no burden of creating a year-long course or grading homework. But because just one or two successful practices "discovered" by those "experts" are not enough for a book, they invent intermediate steps to bloat the content, to add more pages, to get the clout of respectability through sheer weight and number of pages. (Does my previous sentence sound more trustworthy because of the repetition?)
My book recommendation
I recommend Arithmetic For Parents by Ron Aharoni as a good starting point in teaching your child the basics of arithmetics. Ron taught at college, but then decided to try teaching young kids in elementary school. He had to find pedagogical approach different from teaching in college, but this gave him an insight to how young kids should be taught. In short, from concrete to abstract, without skipping even the smallest step.
Really, nothing new, most stuff in the book is common knowledge, but at least he does not give these centuries-old practices new names. It is not a cookbook, but it does have specific teaching advice. It does not suggest how to cut and arrange flash cards for addition facts or multiplication table, but it talks about what number is, what operations mean and why well-known algorithms work.
Also I recommend taking a look at Math-U-See course. I have never bought any products from them, I just watched their videos on YouTube, and they served as inspiration to helping my own son learn math. I did not homeschool him, but I augmented whatever he had in school with my own instruction. For example, here is a Place Value workshop — mesmerizing!
If you are not swamped by your day job and have time to devise math games and playdates and contests and whatnot, I recommend Math from Three to Seven: The Story of a Mathematical Circle for Preschoolers, written by a Russian parent who ran a "math circle" for his children and children of his friends for several years.
Comment: I have heard good things about Math U See.
Comment: So, do you have a recommendation for a book about teaching arithmetic that is similar in approach to Engelmann's? You've mentioned some books and given some opinions about the text/method in question, but where is the answer to the OP's question?
Answer: I wish there were more answers to this!! I agree I love this reading program and I've been looking for a no-brainer math approach that requires little to no lesson prep. I think I'll probably use a traditional workbook. I also found this video helpful. I'm curious about brilliant.org and a friend recommended Mathnasium learning center. I wish there was something like the 100 lesson math book!!

Is there an arithmetic book similar to “Teach Your Child to Read in 100 Easy Lessons” by Siegfried Engelmann?


Is it common to pronounce 'only' as 'own-knee'?

Question: I personally find it very hard to pronounce the 'L' sound right after 'N'. Would you say it is quite common or at least understandable to pronounce 'only' as 'own-knee' (fastly)?
Comment: It is not common in any dialect of English I'm familiar with. As to understandable: context is a very powerful thing and can bear some heavy burdens. That said, by pronouncing it that way you may be opening yourself up to some ridicule, as the only people who say "ownee" are toddlers.
Comment: @DanBron Have a look at sumelic's answer below. Dropping the /l/ (or indeed the /n/) is exceedingly common and done by almost all native English speakers in most environments. It's definitely not just a toddler thing.
Comment: Yes, I think it is common to omit the [l].  I do it in casual conversation.  After the [l] is lost, the [n] is in a flapping environment, so one is left with just a nasal flap as the only consonant in the word.
Comment: @JanusBahsJacquet I'm going to have to reserve judgment on that answer until I do a mini personal study and see if the people say the Ls as frequently as I currently believe they do. If skipping the L was as common as that answe suggests, without some kind of substitute sound, I don't think "ownee" would be as characteristic of toddler-speech as it is.
Answer: To start with, what DanBron said. You are going to have problems if you leave it at that.
In my considerable experience of being a furriner with an accent, I find that it takes two to tango: that is, you have 1) the quality of the furriner's pronunciation and the effort zie puts into it, but also 2) the courtesy and the effort put into it by the native listener. This varies very widely. A linguist once told me that the British are tops at understanding their language when it is phonetically mistreated, by a process of extrapolation. Like when a Japanese in Switzerland asked me the way to "the rake". Some nations and individuals, however, will take no prisoners – they will resolutely refuse to understand a word if you are just ever so slightly off. In the same situation they are going to repeatedly tell the Japanese gentleman that there are no garden tools round here, and consider their duty done.
A similar predicament: for many years I suffered from the East Norwegian inability to understand a person with a non-rhotic or ulvular R. It is no good exhorting me to learn to trill my Rs, I just can't, the way I can't waggle my ears.   The OP may empathise. I seriously thought about making a big badge with the letter R and tapping it, but moved to Bergen where they tend to a throaty R like a Parisian. Which I can do.
Maybe xiver77 can make a badge with the letter L? But seriously, some listeners are never, ever, going to make even the slightest effort to extrapolate from "ownee" or "ownree" to "only". Just avoid them if you can. They're the dummies not you.
Answer: According to the phonetician Jack Windsor Lewis, this pronunciation is commonly used by native speakers but can only occur when "only" comes before another word ("How English is Really Pronounced"). Also, as the other answers and comments on this page indicate, most native speakers don't think that they use this pronunciation. I certainly didn't.

An example of the many words which have weakforms which cause no
  stylistic problem is the word only. This is normal-sounding as given
  in EPD, LPD and ODP as containing an /l/ and it is invariably so
  pronounced in its prepausal occurrences but, whether stressed or not,
  on every other occasion it is overwhelmingly most often uttered
  throughout the whole educated native-English-speaking world without
  any /l/. There is little gain for the EFL learner to be given this
  information and the only admission of the existence of this majority
  form without /l/ is in LPD which quite wrongly categorises it as
  "non-RP". Another word very frequently to be heard without the /l/
  with which it's spelt is certainly which is as often as not pronounced
  /`sɜːtn̩i/ or in a further reduction when not isolated as /`sɜːtni /
  with not even a syllabic /n/. Another such word is occasionally which
  is often /ə`keɪʒni/.

Note that he doesn't think it's useful for non-native speakers to know this information. I've just posted this answer because some people might be interested in knowing this.
Comment: This is the correct answer. I can't imagine myself pronouncing both the /n/ and the /l/ in _only_ unless I'm deliberately enunciating very clearly. In fact, I'd have to disagree with Windsor Lewis that it is "invariably so pronounced in its prepausal occurrences". Perhaps in the specific set of data he was working with that happened to be the case, but even in prepausal position, I would venture that the most common pronunciation, at least in American English, is [ˈoʊ̃ɾ̃i ~ˈoʊ̃ni ~ ˈoʊ̃l̃i], with only one surface consonant present (though I'd say frequently nasalised even if it's the /l/).
Comment: @JanusBahsJacquet: I also wondered about the "invariably" part, but I am certainly less knowledgeable than Lewis. I assume he'd classify [ˈoʊ̃l̃i] as one of the variants that contains an /l/: even if it is nasalized, it's still a lateral.
Comment: Ah, good point—I mentally read "containing an /l/" as meaning "containing both an /n/ and an /l/", but it doesn't necessarily, of course. Even so, "invariably" does seem a strong word to use here.
Answer: With difficult consonant clusters, often the burden of pronunciation is pushed to the next syllable.  A common way people say "only" is "oh-nlee".  This is because there is a desire in English to reduce pauses between consonant sounds.  (None of this is true for compound words, where emphasis often causes the word to still sound like two separate words: boatman, downhill, overboard)
You are probably less likely to be noticed to mispronounce the word "only" if in fact it is said as "oh-lee" than your suggested option (still spoken quickly, as you mentioned).


iPhone 4 camera roll "time created" information

Question: I recently took a photo with my iPhone 4 and soon after e-mailed it to someone. When I downloaded my photos to my computer I noticed that the "time created" information showed a time that was after I had e-mailed the photo. How is that possible?
Comment: What OS downloaded the photos? What software catalogs / shows the time? Can you log in to iCloud.com and verify the info separately?
Answer: Time created means time transferred to your computer. It is the time when the photo landed to whichever folder you downloaded it to, on your computer.
So if you transferred the photo on Monday 1st August 2015, then that is the Date Created shown.
Try downloading an mp3 file from the internet to your computer. You will see that the Date Created is the date that the file enters your computer. While the date of its creation was (obviously) earlier.


Does Air Europa require a tourist visa to Cuba?

Question: Does Air Europa require you to have a tourist visa for Cuba to get on board or can I buy it at Havana Airport?
Comment: Is your nationality one of the ones that's allowed to get a visa on arrival? (That'll certainly make a difference!)
Comment: It totally does not depend on the airline, only on Cuba and your citizenship/residence country.
Comment: The airline *could* make a difference, to the extent that Cuban law and practice treat different airlines differently. And Cuba being Cuba I would not necessarily assume it works like most other countries in the world (where, indeed, the airline does not matter much) but I really don't know if it is actually the case.
Answer: Air Europa would do what all airlines do - ensure you're legally permitted to visit the country (in this case, Cuba).
This would usually mean a check of your passport, nationality, and whether you require a visa before boarding - ie, whether or not you're able to get one on arrival in Havana.
This will depend entirely on Cuba's relationship with your country and whether or not they require you to have visas in advance.
You'll need to check with the relevant government department for your country, or one of the online visa check services. For example, New Zealanders require a visa for entry to Cuba.


What is AssemblyInfo.cs used for?

Question: My question is pretty basic: What is the AssemblyInfo.cs file used for?
Comment: But remember this version number is used along with name, public key token and culture information only if the assemblies are strong-named signed. If assemblies are not strong-named signed, only file names are used for loading.
Answer:
AssemblyInfo.cs contains information about your assembly, like name,
  description, version, etc. You can find more details about its content
  reading the comments that are included in it.
If you delete it, your assembly will be compiled with no information,
  i.e., in the Details tab of the file properties you will see no name,
  no description, version 0.0.0.0, etc.
The value associated with assembly:Guid is the ID that will identify
  the assembly if it will be exposed as a COM object. So, if your
  assembly isn't COM-exposed, you don't need this. It is randomly
  generate. In any case, normally, you don't need to modify it.

Credits goes to : http://social.msdn.microsoft.com/Forums/en/csharpgeneral/thread/8955449f-71ac-448e-9ee6-5329fceecd3c
Comment: What if I want to automate update of version every release.  Is this possible?
Comment: So, if I never change the version number in my AssemblyInfo file then no matter how many deployments I perform it will always show as 126.96.36.199?
Comment: After successfull build in project settings, you can call some .exe to update this number (so it will be the version number for next release, not the one just built). Have a look at: http://www.codeproject.com/Articles/31236/How-To-Update-Assembly-Version-Number-Automaticall
Answer:
In AssemblyInfo file Informational Attributes contains the information about product Name, description, Trademark, copyright. In general this information's are either hardcode or store in database or flat file. .NET assembly provides to store this information in AssemblyInfo file and after compilation it becomes the part of assembly. So at run time one can read this information.
Part of Assembly Information
1 AssemblyTitle : Title name from the assembly.
2 AssemblyDescription: It provides the detail description from the assembly.
3 AssemblyCompany: It Provides the company information from the assembly.
4 AssemblyProduct: It provides the production information from the assembly.
5 AssemblyCopyright: It Provides the copyright from the assembly.
6 AssemblyTrademark: It Provides the trademark from the assembly.
Each of these attributes has a defined class, which is used to read the information from the AssemblyInfo file.

From: https://www.dotnetspider.com/forum/157292-assemblyinfo-file.aspx
Answer: Go to your Project Properties, the Application tab, and click the Assembly Information button.
That's what is stored in AssemblyInfo.cs.
In Windows Explorer, right click your project's .exe output, select Properties, and go to the Details tab. That is the information generated by AssemblyInfo.cs.
Answer: In AssemblyInfo file you can store informations which you can get from every place in the project, so you don't have to update all the places but just the assemblyInfo.
For example - in this file you update the version number, and it is updated automatically in your site.
 In the html page, to get the version number, write:
Assembly assembly = Assembly.GetAssembly(typeof(ProjectName.WebSite.Controllers.MyController));
string version = assembly.GetName().Version.ToString();

and it will be updated each time you upload a new version.
Answer: It is a convenient location for assembly level attributes, such as the version, company name etc.
Answer: AssemblyInfo.cs contains general information about the application you are building, some of these information includes the title of your application, copyright etc, for instance if the title of your application is "MyApplication" you should see something like this:
[assembly: AssemblyTitle("MyApplication")]
Comment: Welcome to Stack Overflow. It's nice to see you involved but please avoid adding answers which don't bring anything new to the topic.

What is AssemblyInfo.cs used for?


How to create a Roll up summary field, activity on leads

Question: I am trying to create a roll up summary field on the lead object that looks up to activity object and counts the number of activities that are not closed. But for some reasons it cannot do that, because the lead object is not the master of a master detail relationship. Are there any alternatives to this? A formula field perhaps?
Answer: The Declarative Lookup Rollup Summary Tool (dlrs for short) is the workaround that you're looking for.
It was originally created by Andrew Fawcett, but control was given to the Salesforce.org Open Source Commons program a few years ago.
It accomplishes that using triggers and/or async apex, but it manages those for you (as well as creating the required unit tests).


Did the Centaurs participate in the Battle of Hogwarts?

Question: Centaurs are the magical creatures lived in the Forbidden Forest, at Hogwarts School of Witchcraft and Wizardry. In Sorcerer's Stone a centaur, named Firenze who rescued Harry in the Forbidden Forest and offers to give him a ride back to the school. Did the Centaurs participate in the Battle of Hogwarts and whose side were they on?
Answer: Not initially, but they joined the fight before the end.
When Hagrid is bringing Harry back from the Forest, he's seen by a procession of centaurs, and Hagrid makes it clear that they didn't fight:

"BANE!"
Hagrid's unexpected bellow nearly forced Harry's eyes open. "Happy now, are yeh, that yeh didn' fight, yeh cowardly bunch o' nags? Are yeh happy Harry Potter's — d-dead…?"
Hagrid could not continue, but broke down in fresh tears. Harry wondered how many centaurs were watching their procession pass; he dared not open his eyes to look. Some of the Death Eaters called insults at the centaurs as they left them behind. A little later, Harry sensed, by a freshening of the air, that they had reached the edge of the forest.
— Deathly Hallows, chapter 36 (The Flaw in the Plan)

Honourable mention must go to Firenze, who did join the fight. As a Hogwarts teacher and outcast from the Hogwarts centaur herd, he was motivated more by his duty to the school and students, than to the whims of the herd:

Behind her stood the remaining teachers, including the palomino centaur, Firenze, and the members of the Order of the Phoenix who had arrived to fight.
— Deathly Hallows, chapter 31 (The Battle of Hogwarts)

Hagrid's speech clearly motivates them to action, because when Hagrid reaches the castle and Voldemort is monologuing, the centaurs charge the castle (accompanied by Grawp). Here are a few excerpts from the book that mention centaur action:

They heard uproar from the distant boundary of the school as what sounded like hundreds of people came swarming over the out-of-sight walls and pelted toward the castle, uttering loud war cries. […]
The slash of the silver blade could not be heard over the roar of the oncoming crowd or the sounds of the clashing giants or of the stampeding centaurs, and yet it seemed to draw every eye. […]
Chaos reigned. The charging centaurs were scattering the Death Eaters, everyone was fleeing the giants' stamping feet, and nearer and nearer thundered the reinforcements that had come from who knew where. […]
The centaurs Bane, Ronan, and Magorian burst into the hall with a great clatter of hooves, as behind Harry the door that led to the kitchens was blasted off its hinges.
— Deathly Hallows, chapter 36 (The Flaw in the Plan)

It includes the three named centaurs from the books, and Bane, who Hagrid called out earlier. So they fought for the defenders of Hogwarts, but initially kept themselves out of it until Harry was (apparently) killed.
Comment: Wish they were included in the movie more, would have been cool to see them in the fight at the end.
Answer: According to an exchange between Harry Potter and Bane in Harry Potter and the Cursed Child, not only did the Centaurs fight bravely, but they were gifted the Forbidden Forest as reward for their timely intervention.

HARRY: I have always respected the centaurs. We are not enemies. You fought bravely at the Battle of Hogwarts. And I fought beside
  you.
BANE: I did my part. But for my herd, and our honor. Not for you. And after the battle, the forest was deemed centaur land. And if
  you're on our land — without permission — then you are our enemy.
Comment: I seem to recall this being said in some interview, though I can not find it. FBaWtFT does imply though that the Forbidden Forest was always set aside for centaurs.
Comment: DAM i was just looking for this question ugugugugug, 4 left


how to prove the complexity of an algorithm mathematically

Question: I know the fundamental algorithms and it's complexities. for e.g if Binary Search has Complexity O(log n), then how I can mathematically prove this?
Comment: This isn't a subjective question in any way, and doesn't belong on programmers.se.
Comment: If you truly know something, then why ask a question?
Comment: Might be appropriate for math.se or cstheory.se
Answer: Big Oh isn't really a description of algorithm complexity, as in how many decisions and branches are made, Big Oh is a description or measure of computing resources used by an algorithm.
Anyways you'll have to become familiar with all the complicated math behind complexity theory, learn about P, NP, EXPTIME complextity classes, and all that fun stuff.
http://en.wikipedia.org/wiki/Computational_complexity_theory
Comment: @Thorbjørn, not strictly true. Big-O is an upper bound: Big-theta is a tight bound.
Comment: @rreeverb: Big Oh is also commonly used to describe memory usage for an algorithm. Hence I used computing resources because time and memory are common limits to a machines capability.
Comment: Big O is a measure of the time an algorithm takes (time complexity). I assume this is what Sarath means by complexity.
Comment: Big O is a measurement of the relative scalability of the algorithm as a function of the input size.  O(n^3) scales with a factor 8 when n doubles.
Comment: @Peter, ok, forgot to write "worst case".
Answer: I assume you're asking about how to measure algorithm time complexity with regards to its input (how the algorithm time grows as N grows). One way is to model the algorithm in the form of a recurrence equation and then solve via a number of techniques. Common techniques are master theorem, substitution, recurrence trees, ...
The binary search algorithm can be seen as recurrences of dividing N in half with a comparison. So T(n) = T(n/2) + 1.  Solve this by the master theorem to show the function is log n.
For a complete overview of this type of stuff I suggest working through these two classes:
http://aduni.org/courses/discrete
and
http://aduni.org/courses/algorithms
Answer: Informally, you would use an argument such as: let f(n) be the number of operations needed to perform a binary search on n elements. Then first argue that the relationship
f(n) = 2 f(n/2) + c
holds, and then use the Master Theorem.
Formally "proving" complexity is something that has always bothered me, since this area of theory seems (at least as presented in introductory computer science) to be trying to apply formal mathematics to a vague, informal foundation. (For instance, what exactly counts as an "operation"?)
Comment: "What counts as an operation" depends on the context. There was an interesting question recently on one of the SE sites about bubble sort being faster than quicksort when sorting on a tape, because then the cost of accessing an arbitrary element of the array isn't constant but depends on the position relative to the tape head - so the partition step of quicksort went from being O(n) to O(n^2).
Comment: I think you have to agree beforehand on a set of operations that make sense. E.g. +, -, *, /, and function application.
Answer: For an introduction to data structures and algorithms, Cormen & al Introduction to Algorithms is really great.
As for the specific case of computing complexities, it is generally a matter of expressing it as a recursive relation, then proving that relation is true, then reducing this recursive relation to a more manageable formula.
The Master Theorem comes handy in the latter step, read the wikipedia article, it should be sufficient for your simple example.
Answer: For Binary Search Only!
Here is my way of doing it:
To implement binary search on a sorted list that contains N elements, we keep dividing the list in halves until we 'corner' the key. This tells us that the problem size decreases by half, [Eg. 100 : 50 : 25 : 12 : 6 : 3 : 1], until it reaches (worst case) 1!
This gives us Geometric progression with a Common ratio = 1/2 and the Nth term being 1.
GP formula is:
An = A1rn-1
which leads to
1 = A1(1/2)n-1
It gets easier after this: Divide both sides by A1, Multiply by Log 2 and solve for N!
Should give you the number of steps to reach An which is Log 2A1 + 1 which in turn is O(log n)
Answer: There are mathematical techniques to prove big-oh. IIRC there where some difference equations involved. Any decent textbook on the topic should be able to teach you the ropes.


How to tell if a SSL certificate is deployed correctly and check if it is working?

Question: I have installed a SSL certificate on a server. Now, I want to check if it is correctly installed and is working. I have heard from my friend that when you are installing your own certificates in keystore the alias should be same as it is in the application code which communicates using port 443 with its partners having same chain of certificates.
Can you tell me how we check if a certificate is correctly installed?
Comment: Well... access to you web server and see the result. If the certificates are wrongly installed, the connection will be most probably dropped, or another certificate will be used. Otherwise, if the right certificate is used, then it means that is correctly installed. Moreover, I think this configuration question would be more suitable on [ServerFault](http://serverfault.com/) which deals with general server configuration issues.
Answer: Use SSL Labs
For a first test, run the URL through SSL Labs:

https://www.ssllabs.com/ssltest/ (Be sure to check the Do not show the results on the boards checkbox.)
Or try HTBridge: https://www.htbridge.com/ssl/ (Be sure to check the Do not display test results in statistics checkbox.)

This will tell you if the certificate is correctly installed when looking at it from the outside.
Keystore alias probably won't matter
Now concerning the "keystore alias": That is only visible from inside the server. So you will have to ask the developers of your specific software if their software cares about the alias. (I don't think it should care about it.)
Comment: I was going through some posts on stackexchange and I found one post suggesting the use of below command to check connectivity: [openssl s_client -connect servername:443 ] will it work in my case?
Answer: I just wanted to point/link to something that I find very useful.
This page, on top of providing a very good explanation of some of the warnings we do get using SSL Test from SSL Labs (they do the same), also provides Windows powershell snippets (or the full script) that will help you getting a better configuration in case you are using Windows in the webserver.


For chemical reactions occurring in the interstellar medium, which involve metal-ions, will the metal ions be solvated or not?

Question: Usually, metal-ions in terrestrial chemistry will be solvated - either by gas-phase solvent molecules or by liquid-phase solvent molecules. But the interstellar medium (ISM) is never in local thermodynamic equilibrium. Moreover, the solvation of any system is driven by the system's proclivity to attain thermodynamic stability. But given the lack of local thermodynamic equilibrium in the ISM, solvation should not at all be an important factor in the ISM. Is it right or wrong? Any reference from the Astrochemistry/Astrophysics community will also be highly appreciated.
Comment: I'm not exactly seeing what you'd imagine as solvation in sth like this.
Answer: Per Wikipedia, the upper bound on the particle density in the interstellar medium is approximately $\pu{E6}$ molecules per cubic centimeter, in "cool, dense regions."
In the context of terrestrial aqueous solvation, where the concentration of water is approximately $\pu{55M}$, the particle density is on the order of $\pu{3.3E22}$.
So, even if every single particle in the vicinity of a metal ion in the ISM were a water molecule, the ISM would be roughly $\pu{E18}$-fold more dilute in neighboring water molecules as compared to aqueous solution.
No, metal ions in the interstellar medium will never be solvated.
Note that this does not imply that it is impossible for aquo-complexes of transition metal ions to occur in the ISM, given their significant affinity for ligands in the first coordination shell and for the appreciable organizing influence (thanks, MaxW!) such ions have on more distant coordination shells. It's just highly improbable that one would find a metal ion associated with a sufficiently statistically large number of water molecules to be considered solvated.

Further, to address the portion of the question about thermodynamic equilibrium: I don't think that's a particularly significant factor, no. On Earth, it's frequently the case that ions are solvated but not in thermodynamic equilibrium: the proton gradient that is sustained in the aqueous milieu of biological organisms to drive ATP synthase is one of the most significant examples that comes to mind. Thus, an absence of thermodynamic equilibrium does not necessarily entail a lack of solvation.
Comment: It is even more improbable. Solvation isn't just about ligands. Because of the dipole moment of water there will be a number of "spheres" (layers)of oriented water molecules around the complex before the water molecules are oriented randomly.
Comment: your answer is enlightening. I fully get your point. Can you please tell if the qualitative thermodynamic argument I listed - ISM not being in thermodynamic equilibrium; can also be a suitable reason for the lack of solvation in the ISM?
Comment: Interstellar medium **is** in equilibrium all right (when they say it isn't, they mean an entirely different thing, mostly related to radiation). But this has nothing to do with solvatation. With densities that low, the equilibrium state would not be solvated either.


Do any academic institutions publish objective surveys of alumni satisfaction?

Question: Having seen some questions asking about the costs/risks/benefits of doing a PhD I wonder if any academic teaching organisations actually contact their students after graduation and seek structured feedback (qualitative and quantitative) about the perceived or actual longer-term costs and benefits of their degree (bachelor's, master's or doctorate).  And if so, do any of them publish the results?  My own alma mater have never asked for feedback (just contributions!).
Comment: I took part in a survey for my *alma mater*, but I have not seen the results yet. [Only the plans to measure success](http://old.northcarolina.edu/reports/index.php?page=download&id=1931&inline=1). And yes, they asked for contributions :). My earlier *alma mater* [did ask a question](http://www.nes.ru/dataupload/files/alumni/NES-Graduate-Barometer/NES-Graduate-Barometer-2012.pdf) about how prepared the alumni felt for the job, with good approval ratings, but it is a small, ridiculously selective institution in a not-so-Western country, and is hardly generalizable to anything.
Comment: @Stask. The plans look quite serious. I suppose that any interest in performance measurement is better than no interest. But the value of self-assessed performance reports is always questionable, e.g. who reports on the students who dropped out along the way?
Comment: One learns from failures more than from successes. So yes, the dropouts should be in the picture. But they are impossible to get -- alumni are hard enough.
Comment: *"objective survey of [...] satisfaction"* Hmmm ... I am *so* glad I'm not in a people science.
Comment: @dmckee. Ha! I guess life must be so much simpler in Physics... dealing with all those concrete concepts like spin, charm, light, virtual photons, ... ;-).
Answer: Yes, here is an example.
A quantitative assessment of the 'long-term costs and benefits' is complicated by the subjective aspects of many parameters. For example, some individuals value salary over independence, other don't. But my alma mater, the Swiss Federal Institute of Technology (EPFL) does objective surveys and statistics on alumni employment. These numbers should be interpreted knowing that answers are given on a voluntary basis and, the EPFL being modest in size, n is small.
Some examples of the results (for 2011):
"One year after graduation, MSc graduates who did not start PhD studies are employed at 90.9% by the industry in Switzerland. It took them an average of 9.5 weeks and 12 job applications to find a job (less than in 2010). Their average entry-level salary (in Switzerland) was CHF 77,967 in the private sector and CHF 76,591 in the public sector (slightly more than in 2010).
One year after PhD graduation, 90.5% of graduates have a job. However, finding a job was harder: they needed an average of 14.9 weeks and 19 job applications (significantly more than in 2010). Salaries are also lower than before, average entry-level salaries were CHF 93,716 in the private sector and CHF 82,720 in the public sector."
They also asked PhD graduates if they think their degree is 'useful for their careers':

29% said it was mandatory,
29% that it gave them significant advantage over non-PhDs,
40% that it was sometimes an advantage, sometimes detrimental depending on the employer,
4% that it gave them no advantage
whatsoever, and
1% had no idea.

Some more data on work satisfaction of PhD graduates:
<code>                    very high    high    average     low     very low
overall sat.        21%          54%     23%         1%      1%
interesting job     19%          51%     24%         4%      1%
adequate training   22%          41%     22%         14%     1%
degree recognition  24%          38%     28%         9%      0%
salary              8%           29%     51%         10%     1%
</code>
Here is the link to the original document (in French).
Notes: translations are mine, 1CHF=~1US$, the MSc is considered the 'undergraduate degree', global unemployment in Switzerland is <4%, PhD studies are funded with a salary of roughly CHF 50'000 with negligible tuition, these are numbers for PhD in sciences and engineering, numbers for humanities are very different.
Comment: Very informative, thanks for abstracting it so clearly. I guess its always going to be difficult to get meaningful data unless enforced by government.  But this does at least seem to show that 75% of PhD graduates were more than averagely satisfied.  It would be interesting to compare different institutions and (as you indicate) the "very different" results for humanities.  By the way CHF 50,000 salary for a PhD student sounds rather good even considering high living costs in Switzerland.
Comment: @steveOw, yes the PhD salaries are good in Switzerland, the 'sacrifice' is much smaller than, say in the US, where you live on meager stipend and lose many years of good pay.


How to save large chat history of WhatsApp in Android phone

Question: I'm not able to store my WhatsApp chat of single contact in email chat because of large amount of messages so how is it possible?
Comment: Sync with Google drive or save locally. WhatsApp > Settings > Conversation > Save conversation > Add your address or save locally
Comment: Why is it a problem to save large files in your email? Are you getting some errors when trying? If so, what are they?
Comment: @esQmo_ are you on the latest version of whatsapp? Cuz i remembered there used to be something similar to what you're saying, but apparently WhatsApp stopped that option, and the only option if saving a single chat with one person is only possible by emailing the chat to yourself. I'm Google drive you can only backup all the chats, and u can't view them unless u restore all at once. Is there something I'm missing?
Answer: Your WhatsApp chats are automatically backed up and saved daily to your phone's memory. You can also periodically backup your WhatsApp chats to Google Drive.
To backup your chats, go toWhatsApp > Menu Button > Settings > Chats> Chat backup > Back Up.
Now, to export a copy of the history of an individual chat or group, use the Email chatfeature instead:
Open the chat for the individual or group.Tap the Menu Button.Tap More.Tap Email chat.Choose whether to Attach Media or not
Note: When sending with media, you can send up to 10,000 latest messages. Without media, you can send 40,000 messages. These constraints are due to maximum email sizes.

Soure: WhatsaApp FAQ


Does supervisord ("supervisorctl start") wait for a command to finish, or fork it off asynchronously?

Question: I'm running supervisorctl start in a shell script and am wondering if I can count on that operation being finished by the time the next line in the shell runs. Thanks!
Answer: You cannot guarantee that supervisorctl start will finish what it's doing.
In fact, if you're running a web server, you should be very thankful that you cannot be sure that the web server has closed once supervisorctl start returns. :)


Seeking Advice: Combining Control Theory, Machine Learning, and Applied Math in Graduate Studies

Question: I'm an electrical and computer engineering undergrad in Portugal, considering a switch to machine learning or applied math for my master's. I've completed Andrew Ng's deep learning specialization and have worked on deep learning projects, including those with transformers. Currently, I'm exploring reinforcement learning and plan to study game theory. My goal is to understand these fields better before deciding on my master's focus. I particularly enjoy signal and control theory in my studies, alongside complex analysis and differential equations, though I don't plan to work directly in these areas. Instead, I aim to apply this mathematical knowledge in programming, avoiding complex proofs.
I'm contemplating a Ph.D. and a career in either industry or government, discouraged by the competitive and flawed academic career path. I'm leaning towards a master's in electrical engineering with a focus on control theory but want to keep options open for deep learning and applied math. I'm curious if it's possible to combine control theory and machine learning in a master's, possibly within a single department, and whether a master's in applied math might be more inclusive of my interests.
I'm also concerned about learning unique subjects like control theory at a level not offered by online courses, while also wanting to maintain the ability to engage with and apply self-learned topics like game theory in my advanced studies. I'm questioning which department (CS, math, or electrical engineering) would best suit a master's or Ph.D. combining control theory and machine learning, if such programs exist in Europe, and how online learning in game theory could integrate into my postgraduate studies.
Any advice on navigating these decisions would be greatly appreciated.
Answer: Don't worry too much about the label of the program or degree.
Find professors who do the kind of work you want to do. Apply to work with them or to the programs that they take students from.
Answer: If you want to do a Master's rather than a PhD, I'd recommed apply to a program with good reputation, where:

a significant part of your graduation requirements can be completed with 'free electives' (i.e. those without any restrictions, incl. department which offers the course); and/or

a significant part of your graduation requirements can be completed with a master's thesis/project if you do find a professor whose research has a major overlap with your focus.


For linear regression, if the theoretical coefficients and the variance of the error is known, is the theoretical R squared value, F statistic known?

Question: For linear regression, suppose we know the true, theoretical coefficients of the predictors (say, for a simulation) and the standard deviation of the error term (sigma). For instance, suppose we know the true relationship is:
y=5 + 4 * x1 + 8 * x2 + error, where error is N(0, variance = 4)
If we are given n values for the predictors x1, x2. We would also know the theoretical variance of the estimated coefficients, and can also obtain the theoretical confidence interval for the coefficients and predictions.
But what about R squared and the F-statistic? Is there a way to calculate the "theoretical" or expected value for those given that we know the real coefficients and sigma? How is R squared and F-statistics distributed? For instance, we know for any given coefficient, it is normally distributed with the mean corresponding to the true value, and the standard deviation depends on sigma.
Thanks
Comment: "If we are given n values for the predictors x1, x2." So you know the values of the regressors?  $F$ & $R^2$ depend on the distribution of $\bf X$, so if you do, then yes, otherwise, no.
Answer: In this very artificial situation, the "F" statistic has a scaled chi-squared distribution, because sigma is known. R squared can be written as a function of the F statistic, so it has a related distribution.


Ultimaker Original+: print has lumps and small gaps are being filled

Question: Brand new to 3D printing and have an Ultimaker Original + using PLA (2.85mm).
The nozzle/extruder temperature is 200C and the bed/plate is 60C.
I installed the Cura software on my Windows 10 box. I then head on over to tinkercad.com to make a model of a comb. I then exported my .STL file and loaded it up in Cura. I hit the print button. I waited a bit, but noticed that my print was getting lumps in it. Not crazy drastic lumps, but because the object was small, gaps (between the comb teeth) were being filled... not all of them, just some.
I tried adjusting the flow rate from 100% to 90% and it seemed a little better (not perfect, still filling gaps), but when I dropped it lower, it got worse.
I also tried to lower the print speed from the default of 60mm/s to 50mm/s - no change. (travel speed at 120mm/s)
I tried to adjust the bed height multiple times, trying to make sure that it was 100% flat at 180 degrees.
What is wrong here? Is the printer over extruding? Is the temperature too high? Is the flow rate wrong? Am I missing something else?
Check out my prints:

I also tried printing something else:

Any help would be really appreciated.
Update
Okay, so thanks to macs answer, I took another look at the nozzle and noticed a massive leak - I actually dismissed this earlier as "glue" - OMG.
Anyways, here is the picture of the leakage:

It's very bad. It leaks down and runs over the nozzle. The nozzle also leaks... Is that normal? All I did was turn the printer on, heat up the nozzle to 200C and it started to leak. I suspect that it should not do this... I'm not ready to change the nozzle just yet - I've no idea which one to buy or even where to buy it from (I'm in the UK), so I'd like to get this one working (if possible).
On another note, I have checked the filament settings - All good. Heat settings all good too:
Comment: Did you lower the temperature? I use 190-195 degrees for PLA and 50 degrees for printing bed. It looks like the object does not stick well to the printing bed. Am I right?
Comment: @Marco I didn't try to lower the temperatures, no. However, the object actually sticks very well to the bed... I need to pry it off.
Comment: What nozzle diameter?    And have you played with the retraction setting?
Comment: Are you sure your nozzle isn't dripping?
Answer:
What is wrong here? Is the printer over extruding? Is the temperature too high? Is the flow rate wrong? Am I missing something else?

It is always difficult to diagnose problems from a set of pictures only, and without the original model to compare it with, but yes, from the pictures it looks like your printer has a severe case of over extrusion, possibly in conjunction with a thermal problem.
The first picture in the set is particularly interesting for a number of reasons:

The chequered pattern of the top layer looks like being generated by the nozzle "digging" in the layers below and rising the plastic around it.  A well calibrater printer should have a top surface with a very subtle texture instead.

The teeth of the comb and the gap between them are inconsistent, as are the shape of the tip of the teeth.  This let me think your printer actually doesn't operate consistently, over-extruding in some places a lot more than in others.  A pinter should be able to accurately replicate its performance along the full length of the comb instead.

The plastic has a different finish and colour in different places.  Namely, it looks burnt and glossy where the worse print quality is, white and matte where the problems are not so bad.  Both the colour and the finish let me thing the plastic in the dark spots have been heated way over its operational range and/or for too long.

In essence what I think it is happening (mind it: this is just a theory) is that your printer is over-extruding and in addition your hot end may have issues with keeping its own temperature constant and within the designed limit.  Other factors that may also play a role could be:

Wrong settings in the slicer as for example a nozzle diameter set to 0.5 mm when it really is 0.4 mm instead, or the filament diameter being wrong.
Blobs of over-extruded material forming and sticking to the nozzle, where they take too much heat for too long and burn before "falling" in the print and damaging it.
Filament that is old/of bad quality and that has impurities in it, or has an inconsistent diameter along its length (thus causing over-extrusion in places, but not in other).
A nozzle that is not well fixed to the heating block, thus allowing molten plastic to seep out from the joint and run down on the outside of the nozzle and ultimately on the print itself.
A nozzle that got damaged and whose opening is not circular and/or not matching its nominal diameter.
The extruder hobbed gear not e"biting" in the filament and thus the filament slipping at times, thus being inconsistent in the quality of material being extruded.

So, here's the the trouble-shooting I would go through at this stage:

Check your printer setting in the slicer.  Doh! :)
Take a close look at how the print works while in operation.  Do you see blobs forming and sticking to the nozzle?  Plastic seeping out from places it shouldn't?  Is the nozzle round and true?  In case of doubts, just change the nozzle with a new one (it is a less-than-1€ part anyways), easily outspent by the cost of filament in a failed print.
Calibrate you extrusion (and thus your flow-rate) by performing accurate measurements over at least 3 length of filament.  Matterhackers has a nice how-to that you can follow for this.
Manually check the diameter of your filament (at least 5 measurements at at lest 200 mm distance between them) and adjust the corresponding "filament diameter" setting.
Calibrate your temperature by using a test tower.  This one has extensive instructions on how to use it in the thing description, plus is customizable directly from thingiverse.
Print again your model and see how/if your changes affected the print quality in any way.

If the above fails, you could also try to use another slicer, but it's unlikely the problem is with the software.
UPDATE
I'm not familiar with your printer model, but the updated pictures seems to show the leakage happening between the heat block and the heat break, rather than between nozzle and "whatever". ;)
This can actually be caused by two different problems (or the two of them compounding).

The two parts, which are normally just screwed together have come loose.
If your extruder is not "all metal" (which is normally not the case in most printer), the PTFE tube (the whitish plastic tube the filament slides into) may have dislodged upwards, so instead of being a tight fit in the heat block, it leaves room for the molten filament to seep upwards.

In both cases, a reassembly and thorough clean-up of the head is in order.  I would suggest trying to find specific documentation for your printer online, but the general process is:

warm up the head to printing temperature.  All subsequent steps will have to be done at this temperature (wearing protective gloves is highly  recommended)
remove the filament
remove the PTFE tube
remove the nozzle
remove the the heating block from the heat break
wipe as much the plastic as possible (bit drills work well for the hole in the heat block
increase the temp a further 20-30 degrees
reassemble everything
profit

Please note:

the heat break is relatively fragile: be gentle when unscrewing.  When removing/attaching the nozzle is worth keeping the heat block in place with a spanner to prevent twisting the heat break
if you can't remove the plastic when molted, you can try letting it cool and scrape it
it essential that the re-assembly be done while hot.  Metal expands with heat, so what feels firm while cold will eventually become loose at high temperature
Comment: Hey, thank you for the detailed response. Your question `Plastic seeping out from places it shouldn't?` caught my eye - I do indeed see leakage. I took a closer look... turns out it is leaking very badly between the nozzle and the tube/pipe/whatever. I'll add a picture to show.
Comment: @pookie - I updated my answer above, let us know how it goes and mind that disassembling the hot end is probably the trickiest maintenance operation to be done on a printer, so don't get discouraged should you find it difficult to perform!  Take your time (or find a friend/hackerspace that may show you how it is done). :)
Comment: Thank you :) I will go through the process of removing, cleaning and reassembling the unit and let you know how I get on. I've read a lot of stories about people snapping the tube... It's my wife's work printer, so what the heck? I've got nothing to lose! :)


What's the difference between a single-contact alveolar trill and alveolar flap/tap

Question: is there any difference between the two? is it even possible to produce an alveolar trill with a single vibration of the tongue?
Comment: No difference, except that if there's only one contact it's not a trill, just a tap.
Comment: It's not possible to produce a trill with just one vibration/contact, because _that is a tap_. The definition of a trill is multiple taps in rapid succession; if there's only one, it fails the definition.
Comment: What you're asking is like asking about a difference between a one-storeyed cottage and a one-storeyed skyscraper. :-)
Answer: I suggest consulting Ladefoged & Maddieson The sounds of the world's languages, p. 217 ff for the distinction. They state that

The primary characteristic of a trill is that it is the vibration of
one speech organ against another, driven by the aerodynamic
conditions. One of the soft moveable parts of the vocal tract is
placed close enough to another surface, so that when a current of air
of the right strength passes through the aperture created by this
configuration, a repeating pattern of closing and opening of the flow
channel occurs

...

a sufficiently narrow aperture must be created and an adequate airflow
through the aperture must occur. The aperture size and airflow must
fall within critical limits for trilling to occur, and quite small
deviations mean that it will fail

Therefore, they note that

trills tend to vary with non-trilled pronunciations. So with trills,
as with voicing, there is a potential conflict between an acoustic
definition (more than one period of actual vibration) and an
articulatory definition (positioning of the articulators in a
configuration such that, given the right aerodynamic conditions,
vibration would occur).

They then resolve this conflict, saying that

we will consider trills to be sounds made with an articulatory
configuration appropriate for vibration, regardless of whether
vibration actually occurs.

Accordingly, a single-trill trill is not the same as a flap/tap, but only if you accept their articulatory definition of a trill. As for flaps and taps,

a flap is a sound in which a brief contact between the articulators is
made by moving the active articulator tangentially to the site of the
contact, so that it strikes the upper surface of the vocal tract in
passing; a tap is a sound in which a brief contact between the
articulators is made by moving the active articulator directly towards
the roof of the mouth.

So it depends on how you define tap, flap and trill.
Catford, in A Practical Introduction to Phonetics, does not "define" trills, but his description of them (p. 66) is based on articulation, not acoustic result – I would say that there is no disagreement between Catford and Ladefoged & Maddieson on what a trill is.


What's the by-the-rules difference between a Heavy Crossbow and a Large-Sized Light Crossbow?

Question: I'm not particularly clear on how this is supposed to work, but it seems like a Large-Sized Light Crossbow is better in most respects.
Answer: Using an inappropriately sized weapon applies a -2 penalty to hit, and raises the weapon by one 'category' (light->one-handed->two-handed->unusable). So, to use your example, a Large Light Crossbow, while it would do the same damage as a Heavy Crossbow, would have a penalty to hit and a shorter range. There's no good reason to do it.
Further, depending on your GMs interpretation of the RAW, it can be argued that an oversized crossbow requires two hands to shoot, and cannot be reloaded, as those tasks require one hand and two hands respectively with a properly-sized weapon.
Comment: Exactly, a heavy cross bow essentially *is* a 'large light crossbow'.  An unassisted person isn't capable of loading one.  That's why they have the ratchet/winch assisting devices for loading.


Thomson scattering on the electrons does not produce any circular polarization?

Question: All references on CMB polarization has this statement as if it is a trivial fact. But I have to admit that I completely don't understand what this sentence is telling us.
Answer: Unpolarised light can be regarded as an equal mixture of perpendicular polarisations with random phases. The perpendicular polarisations cause perpendicular oscillations in an electron which then re-radiates in all directions except along the axis of an oscillation. The resultant scattered light is partially linearly polarised (because the two polarisation components, although still having a random phase relationship, are not scattered equally in all directions) or completely linearly polarised if observed at right angles to the incoming radiation.
For example, see the animations here.
To get circular (or elliptical) polarisation would require a fixed phase relationship between the two polarisation components of the light that is being scattered. The only way to arrange this is if the light that is being scattered is already circularly (or elliptically) polarised and even then, the scattered light has a reduced circular polarisation unless observing in the exact forward or back-scattered direction.


How can I predict the last element of the fixed length=8 sequence after I get each element?

Question: There are fixed length lists [X1, X2, X3, X4, X5, X6, X7, X8] like this.
I have many lists like them from the past. In the future, I will get new element of current list on weekly bases. one new element for each week.
what machine learning model can I use to predict the last element as soon as I get new element ?
Answer: This can be modelled as a Markov Chain.
Let us say each element in your list can take N states. You can then represent a first order markov chain by build an N x N matrix - where each cell represents a state transition probability.
You can use this state transition probability to predict the most likely value X9 takes based on the known value from the previous timestep X8.
You also have the option of using a higher order markov chain - for e.g. a second order chain could allow you to predict X9 based on values from the previous 2 timesteps - X7 and X8.


Can AIs manage elements of my company for me?

Question: I recently found an AI for OpenTTD that sets up feeder bus stops in cities and sends them to an airport. What I'd like to be able do is not compete against this AI, but rather have this AI manage cities for me for which I have an airport built. Is such a thing possible, or do AIs exist strictly as competition?
Comment: I've a *feeling* you might be able to share a team (company) with an AI player during a multiplayer game, to get an effect something like this. But it's not something I've tried before, and I'm at work so can't test at the moment. It might be than joining an AI team removes the AI control, I don't know... consider this speculation for now...
Answer: At present, AIs are exclusively for competition. This is probably in part because OpenTTD, more so than its progenitors, is a multiplayer game, and giving players access to that kind of automated tools would damage game balance.
There might exist patches that'll let you offload certain aspects onto AIs, but that carries with it its own set of problems (compatibility with trunk saves, for one, and also the fact that quite a few patches appear in one version, remain supported for a few version, and then wither).
Additionally, half the fun of a game like OpenTTD is all the micromanagement. ;)
Side note:
One patch designed to alleviate some micromanagement issues, albeit in a different maner from what you describe, is cargodist, which is well-supported and popular, but the above notes on versions and support still applies.


Shutting down or ringing an alarm when the phone leaves a certain range

Question: I need to make the phone available for all people in a building, for example.  If someone were to try to walk outside of the building with the phone, the phone would shut down or a loud alarm would sound. Any thoughts?
Comment: Do you mean by accident (forgot that you had the phone in your pocket) or on purpose (theft)? Most answers so far only work for the first case. For the second case you need something that will survive the user doing a factory reset on the phone before walking out. Not aware of anything that can do that.
Comment: In this case I don't think you can do much against a factory-reset and walk-out. Your best bet may be to have the phone have a constant network connection to one of your servers telling the server where it is and the server sounding an alarm if it loses contact or doesn't approve the location. However this does not tell you where the phone is or who has it and it also may cause frequent false alarms if the network drops out for other reasons.
Comment: Yes, on purpose.  We are trying to use the android platform for patients to fill out forms in an office, but need to find a way to keep them from leaving the premise.
Answer: As Lie says, you can achieve most of this with Tasker (Market link or Dev's Site) .  Tasker can detect your phone's location using GPS or based on the cell towers or wifi access points it can see.
I don't think you can set the phone to shut itself down based on this, but you could definitely make it play a loud sound, or even send an SMS message or a voice call to a particular number.
Answer: Matt H's answer in conjunction with Prey might be useful for you.
Have Tasker send an E-mail when the phone leaves the building.  You read the E-mail and mark the phone as "stolen" in Prey.  Prey gives you a lot of options about how you want your phone to react to being marked as stolen.  You can lock it down and force the GPS to stay active as long as the battery isn't dead, letting you know where the device is.
Yay for daisychaining answers, btw.
Answer: You can probably do this with Tasker or Locale.


Transpose of an operator with respect to a fixed but arbitrary orthonormal basis

Question: I've read an article which features the transpose of a bounded linear operator $A$, denoted by $A^{t}$. I have no idea what is this $A^{t}$ all about. Is this actually an adjoint? Are the transpose of an operator and the adjoint of an operator the same thing? Can you please help me on this. I'm a bit confused. Kindly look at Theorems 3.3 and 3.4 of this article. http://www.scielo.cl/pdf/proy/v33n4/art04.pdf
Comment: Just look up the definition: https://en.wikipedia.org/wiki/Hermitian_adjoint
Answer: In a finite dimensional vector space the adjoint $A^\dagger$ of a linear operator $A$ is represented by the complex conjugate of the transpose matrix that represents $A$ ( and this is true in any basis). This implies that in a real vector space theadjoint is simply the transpose.
For an infinite dimensional space the ''transpose'' of an operatore cannot be defined in terms of representative matrix, so we define the adjoint of a linear operator $S$ as the vector $A^\dagger$ such that
$$
\langle A^\dagger x, y\rangle = \langle  x,A y\rangle
$$
where $\langle \cdot, \cdot \rangle $ is the inner product in the Hilbert space.
With an abuse of language, if the Hilbert space is over the reals, we can call this operator $A^\dagger$ the ''transpose'' of $A$.
As an example, if $A=\frac {d}{dx}$ on the space of real valued continuous functions  on $[0,1]$  and such that $f(0)=f(1)=0$, with the inner product $\langle f(x),g(x)\rangle=\int_0^1 f(x)g(x)dx$, we can prove, using integration by part, that $A^\dagger =-\frac{d}{dx}$ and we can call this the ''transpose'' of $A$.
But note that the   $A^\dagger$ depends not only from the operator, but also from the vector space and from the inner product.
Comment: so what's gonna happen if the Hilbert space is over the field of complex numbers? the so-called "transpose" is no longer the adjoint?
Comment: I think that in this case the use of ''transpose'' is misleading.
Comment: in an infinite dimensional Hilbert space (or any vector space in general), does a "transpose" still need an orthonormal basis of the space? That's what has been written on the article that i cited in my question, particularly on Theorems 3.3 and 3.4.
Comment: I have read one definition about the transpose. It looks like the adjoint but not quite. The definition goes something like this. The transpose of $A$ is the operator $B$ such that $\langle Ax, y \rangle = \langle By, x \rangle$. This is for the field of complex scalars. But for the field of reals, the transpose becomes the adjoint since the conjugate of $\langle By, x \rangle$ is just $\langle x, By \rangle$. How do you find this definition? is this precise?
Comment: Well,since the inner product is commutative, it seems the same definition as in my answer, with your $B$ as my $A^\dagger$.


Drop ceiling in a bathroom

Question: I'm thinking of installing a drop ceiling with acoustical tiles in a basement bathroom.
Will this be a problem with moisture even with an exhaust fan installed?
Answer: This should not be a problem. While a drop ceiling is not as well sealed as a typical drywall ceiling, as long as the panels are in place it is good enough. There are many varieties available. While most should be fine with moisture, you may want to look at vinyl or other materials that specifically mention waterproof/water resistant capabilities.

Drop ceiling in a bathroom